Forza Engineering Division (closed)

[Vitaphone Racing]

closed thread, don't post

Armoured Vehicle Diesel Powerplants
FB-12TSD-SHO - Out of production
FB-12TSD-HO-UL - Out of production
FB-12TSD-HO - Out of production
FB-12TSD - Out of production

Amoured Vehicle Diesel-Electric Powerplants
FB-6TSDH - Out of production
DFB-12ETDH "GreenTank" - Concept
DFB-12ETDH Serie A

Locomotive Diesel-Electric Powerplants
DD020-X

Commerical Vehicle Diesel Powerplants
K-Series

[Vitaphone Racing]

Forza GreenTank Project

Introduction

The Forza GreenTank project is a design study to create a propulsion system for an Armoured Fighting Vehicle operating where carbon-based fuel is at a premium. GreenTank uses technologies that have been pioneered on race cars, small passenger cars and diesel-electric trains to work towards a fuel consumption goal of 1.5 Litres per kilometer.

Internal Combustion Engine

The Forza HDrive uses two internal combustion engines. Each is a Flat-6 unit displacing a relatively small 8 litres, forcibly inducted by Forza's eCharge aspiration system and teamed with Forza's HybriDrive technology which altogether creates the hybrid diesel-electric drivetrain.

Due to requirements to use a hybrid drivetrain, the engines needed to be kept physically small to maximise available space in order to fit the generators and battery packs required for the hybrid system. This led to the demand for a small-displacement engine which would keep external dimensions to the minimum and that would also be more efficient than a larger engine when at light load, such as speeds above idle. Maximum power produced by the ICE does not need to be as high to equal other vehicles for power to weight ratio, as the power provided by the motor generators in parallel to the ICE would be sufficient to address the diffence in power levels.

The two Flat-6 engines are stacked on top of one another to form what resembles a flat-H engine, except with no mechanical connection between the two crankshafts.

The engine has a specific output of 52 kw per litre, to put this into perspective the HDrive engine yields roughly the same amount of power per litre compared to the FB-12TSD which powers the AY2-1E Panthera Tigris MBT, one of the most powerful engines ever fitted to an MBT, despite consuming half of the fuel. The output is a product of the engine's low compression ratio, relatively high maximum engine speed and very high staged boost levels which are explained later. Each cylinder displaces 1,333 cubic centimetres. The total power of just the two ICE's alone is a mere 832kw however the hybrid system can contribute an extra 800kw to this total when the engine is at it's maximum output, giving a total output of 1632kw or over 2150 horsepower.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

Combined with the more efficient fuel burn and the increased flexibility of the forced induction system, this drivetrain increases specific power while reducing fuel consumption.

Low Compression Ratio

The engine itself makes use of an extremely low compression ratio of 14:1, putting it on equality with the lowest compression diesel engines fitted to passenger cars and possibly the lowest ever seen on an AFV. Diesel engines generally have a very high compression temperature and pressure at piston top dead center. If fuel is injected under these conditions, ignition will take place before an adequate air-fuel mixture is formed, causing heterogeneous combustion to occur locally which essentially results in an inefficient combustion reaction.

When the compression ratio is lowered, compression temperature and pressure at top dead centre decrease significantly. Consequently, ignition takes longer when fuel is injected near top dead centre which allows for a more desireable mixture of air and fuel. This alleviates the formation of NOx and soot because the combustion becomes more uniform throughout the cylinder without localized high-temperature areas and oxygen insufficiencies. Furthermore, injection and combustion close to top dead centre result in a highly-efficient diesel engine, in which a higher expansion ratio is obtained than in a high-compression-ratio diesel engine, thus meaning the engine can produce more force with a single stroke.

Due to its low compression ratio, the maximum in-cylinder combustion pressure for this diesel engine is lower than other typical heavy diesels which allows for significant weight reduction through structural optimization, essentially lightening the engine where possible and reducing it's exterior dimensions. Because the stresses placed on the cylinder block by compression are much less than other diesels, the engine does not need to be engineered to withstand these forces and thus weight and exterior size can be shedded.

Also due to the lower combustion ratio, internal componenets such as the crankshaft were also able to be adapted due to a lesser stroke being required. This in particular reduces mechanical friction by a considerable percentage. Because the internal components and the engine block have much less stress placed upon them, they are able to last longer than components of other diesel engines, which results in not only a more fuel efficient engine but also one which is more reliable.

Cold starting and misfiring

There are only two primary problems that have been preventing the spread of low-compression-ratio diesels in modern applications regardless of their numerous advantages. The first is the fact that when the compression pressure is reduced, the compression temperature during cold operation is too low to cause combustion, which means the engine cannot be started. The second is the occurrence of misfiring during warm-up operation due to lack of compression temperature and pressure.

Forza engineers decided that the problem of a reduced compression temperature could be fixed by simply altering the amount of fuel injected when the engine is starting, thus calling for a variable fuel injection system which would be electronically controlled. The newly adopted multi-hole piezo injectors allow for a wide variety of injection patterns and can inject fuel in increments of 10^-9 of a litre and at temepratures of up to 2000 bar. Precision in injection amount and timing increases the accuracy of mixture concentration control which means the engine can start in all conditions no matter how cold the temperature is.

Ceramic Fast Glow Plugs developed by NGK also help the cold start capability. As opposed to a metal pin-type glow plug, the heating coil of a ceramic glow plug has an especially high melting point. It is also sheathed in silicon nitrite, an extremely robust ceramic material. The combination of the heating coil and ceramic sheath enable higher temperatures and extremely short preheat times due to excellent thermal conductivity. Also, ceramic glow plugs have a more compact design. This is important, because there is very little free space in today’s engines. NGK NHTC glow plugs achieve a temperature of 1,000°C in less than two seconds and can after-glow for more than ten minutes at temperatures of up to 1,350°C. Optimum combustion is ensured even at low compression ratios. In addition, the NHTC glow plug can glow intermediately to prevent cooling of the particle filter in deceleration phases.

The commonrail fuel injector is capable of a maximum of 9 injections per combustion, injecting at up to 2000 bar in very precise amounts. Along with the three basic injections: pre-injection, main injection, and post-injection, different injection patterns will be set according to driving conditions which are controlled and governed automatically by the engine control unit. Definite engine-start even with a low compression ratio is attributable to this precise injection control and also the adoption of ceramic glow plugs.

Any misfiring that may occur during warm-up operation after engine-start is prevented by adopting a variable valve timing system for the exhaust valves, similiar to the one seen on other Forza engines. From studying diesel engines, it was noted that just a single combustion cycle is sufficient for the exhaust gas temperature to rise. Given this, the exhaust valves are opened slightly during the intake stroke to regurgitate the hot exhaust gas back into the cylinder, which increases the air temperature. This promotes the elevation of compression temperature which in turn stabilizes ignition and greatly reduces if not eliminates the chance of a misfire.

Dual engine layout

The use of two seperately controlled internal combustion engines is designed to reduce the fuel consumption and emissions of an internal combustion engine during light load operation. In typical light load driving the driver uses only around a quarter to a third of an engine’s maximum power. In these conditions, the throttle valve is nearly closed and the engine needs to work hard to draw air for combustion. This causes an inefficiency known as pumping loss. Some large capacity engines need to be throttled so much at light load that the cylinder pressure at the zenith of the cylinder is approximately half that of a small engine half the size. Low cylinder pressure means low fuel efficiency and fuel consumption begins to sky rocket.

Deactivating one engine at light load means there are fewer cylinders drawing air from the intake manifold which works to increase its fluid (air) pressure. Operation without variable displacement is wasteful because fuel is continuously pumped into each cylinder and combusted even though maximum performance is not required. By shutting down effectively half of vehicle's cylinders the amount of fuel being consumed is much less. Between reducing the pumping losses which increases pressure in each operating cylinder and decreasing the amount of fuel being pumped into the cylinders. Fuel consumption for large capacity Forza engines can be reduced by 20 to 35 percent in highway conditions.

The two internal combustion engines are identical flat-6 engines designated #1 and #2 as discussed above. One engine is designated the primary engine while another is designated as the secondary; due to wear and tear issues, the designations switch automatically on the hour to ensure an adequate amount of down time for each engine.

The primary engine will operate whenever the tank is not relying on battery power for movement or to provide power to the systems which make up the tank. The secondary engine only activates on demand; ie when the primary engine can not sustain the amount of power required by the vehicle at the present time.

Each ICE is connected to a motor/generator as will be discussed later. The two engines power the generator which stores the energy created in the battery packs, relying on the remaining electric motor/generators to convert the electrical energy into motion.

Forced Induction

The GreenTank project debuts Forza's eCharge system, using electrically powered compressors to forcibly aspirate the engine rather than using exhaust powered turbochargers or mechanically driven superchargers. The eCharge system is not only more efficient than typical methods, but the lesser number of moving parts in extreme conditions also improves the reliability of the system.

Each engine mounts two compressors; one for each bank of cylinders, amounting to a total of four for this particular drivetrain. The system also mounts a total of two turbines which are used to recollect energy from the exhaust gases.

Using ultra-high voltage wires to minimize power loss, stored battery power is transferred to a series of electric motors in one of the system's compressors. There, the motors are used to accelerate the compressor to full operating speed to ensure the maximum amount of boost is available. The Forza EMS (Engine Management System) controls the air flow rate and boost pressure via control of the compressor speed which allows for a precise and effective fuel flow rate for combustion.

The compressors used are Variable Geometry Turbochargers which are well suited to diesel engines and were first used by Forza on the Corio series of commercial truck. VGT's allow the effective aspect ratio of the turbo to be altered as conditions change. This is done because optimum aspect ratio at low engine speeds is very different from that at high engine speeds. If the aspect ratio is too large, the turbo will fail to create boost at low speeds; if the aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust manifold pressures, high pumping losses, and ultimately lower power output. By altering the geometry of the turbine housing as the engine accelerates, the turbo's aspect ratio can be maintained at its optimum. Because of this, VGTs have a minimal amount of lag, have a low boost threshold, and are very efficient at higher engine speeds. VGTs do not require a wastegate.

At high engine speeds there is more energy generated by the turbine than is required by the compressor. Under these conditions, the excess energy can be used to recharge the energy storage for the next acceleration phase or used to power some of the auxiliary loads such as an electric air conditioning system.

The system can operate in what is commonly known as a 'steady state,' where the power produced by recycling the energy from the exhaust gases through the exhaust turbines matches the power consumed by the compressors. This prevents the system from draining the batteries.

Signature Reduction

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are particualrly ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY1 is much quieter inside and out than any other MBT.

Hybrid Drivetrain

The Forza HybriDrive replaces a normal geared transmission with an electromechanical system. Because an internal combustion engine (ICE) delivers power best only over a small range of torques and speeds, the crankshaft of the engine is usually attached to an automatic or manual transmission by a clutch or torque converter that allows the driver to adjust the speed and torque that can be delivered by the engine to the torque and speed needed to drive the wheels of the car. For classification purposes, the gearbox can be described as an Electronic Continuously Variable Transmission, or EVT.

The HybriDrive system replaces the gearbox, alternator and starter motor with a three-phase brushless alternator serving as a generator, two powerful motor-generators, a computerized shunt system to control the afforementioned devices, a mechanical power splitter that acts as a second differential, and a battery pack that serves as an energy reservoir. The motor-generator uses power from the battery pack to propel the vehicle at startup and at low speeds or under acceleration. The ICE may or may not be running at startup. When higher speeds, faster acceleration or more power for charging the batteries is needed the ICE is started by the motor-generator, acting as a starter motor.

When the operator wants the vehicle to slow down the initial travel of the brake pedal engages the motor-generator into generator mode converting much of the forward motion into electrical current flow which is used to recharge the batteries while slowing down the vehicle. In this way the forward momentum regenerates or converts much of the energy used to accelerate the vehicle back into stored electrical energy.

The sole purpose of the brushless alternator is to convert mechanical energy generated by the ICE and convert it into electrical energy which is stored in the battery pack. In addition, by regulating the amount of electrical power generated, the alternator also controls and regulates the transmission of the vehicle by changing the internal resistance of the alternator. The pair of motor generators drive the vehicle in tandem with the ICE. The two roles are not interchangeable. When the four motor generators are in operation, they create an extra 800kw of power between them.

The two ICE are geared independantly to the EVT transmission where their power and torque is combined and then split.

The mechanical gearing design of the system allows the mechanical power from the ICE to be split three ways: extra torque, extra rotation speed, and power for an electric generator. A computer program running appropriate actuators controls the systems and directs the power flow from the different engine and the electric motor sources. This power split achieves the benefits of a continuously variable transmission (CVT), except that the torque/speed conversion uses an electric motor rather than a direct mechanical gear train connection. The vehicle cannot operate without the computer, power electronics, battery pack and motor-generators, though in principle it could operate while missing the internal combustion engine.

The transmission contains a planetary gear set that adjusts and blends the amount of torque from the engine and motors as it’s needed. Special couplings and sensors monitor rotation speed of each track and the total torque on the tracks, for feedback to the control computer.

Advantages of a Hybrid

In summary, the HybriDrive system works by the brushless alternator feeding electric power to the battery pack where it is stored, before it is supplied to the two motor generators which rectify the electric energy into mechanical energy, where it is then used to drive the tracks. Furthermore, during normal operation the engine can be operated at or near its ideal speed and torque level for power, economy, or emissions, with the battery pack absorbing or supplying power as appropriate to balance the demand placed by the driver. During stoppages the internal combustion engine can be turned off for a greater fuel economy.

Two other advantages are made possible by this set up.

The first is "Stealth Mode," where the vehicle can travel at slow to medium speeds without using the ICE for power, thus running silently. This gives an assaulting force an enourmous advantage as an enemy will generally not be able to hear the AFV approaching, except over rough ground which would cause noise. However, the absence of an engine note will mean that the noise of the tracks on the ground alone will not alert the enemy to the presence of an AFV. In this mode, the alternator spins freely and the engine is de-coupled from the rest of the drivetrain. Stealth Mode can be run for up to fourty minutes or fifty kilometres running off the battery power. After this, the ICE will need to recharge the battery pack.

The second is the "Overboost" function. When accelerating, the vehicle teams the powerful ICE with the pair of motor-generators to combine their power and torque, resulting in a huge boost to acceleration. The Overboost function can also be employed for the vehicle to act as a tug, by either pushing or pulling an otherwise immobile vehicle, up to an eighty tonne MBT, to a safer position.

The drivetrain can also be programmed to switch off the ICE and rely soley on electric power when travelling for periods of time at constant speeds to conserve fuel. Although this doesn't do much to help fuel economy during combat manuevers, a great amount of fuel can be saved when the vehicle is (not sure how to word this part, basically whenever the tank is cruising but not in an area where the speed is likely to fluctuate greatly). In a world first for a tank, the ICE is fitted with a start/stop mode which automatically kills the engine when the engine comes to idle to conserve fuel further. If the engine is still set to "on," the driver simply needs to increase the throttle and the engine will quickly restart, or the engine will automatically restart when the reserve battery power dips below 10%.

Maximum Power: 1632kw
Maximum Torque: 8900nm (@idle, electric motors)
Weight (system): 5,700kg
Engine Type: 2x Flat-6 Engines + 2xElectric Generator, 4x Electric Motors
Displacement: 15.988 litres
Induction: Quad Electronic Turbocharger
Fuel Diesel

Applications: None as of 1st September 2011

OOC: Credit goes to:
General Electric
Detroit Diesel-MTU Australia
Siemens
Mazda
Volkswagen
Toyota
NGK
Borg Warner
And any other source I used for research that I have forgotten.

[Vitaphone Racing]

Powertrain system for the AY1 Serenity MBT, produced by Yohannes

Engine: Forza FB-12TSD Flat-12 Cylinder Boxer Twincharged (Supercharger + Twin Turbocharger)
Fuel consumption: 2.2L/km
Transmission: Forza 8GDCT Automated Double Clutch Transmission, (8 forward 4 reverse)

The primary propulsion system of the AY1 MBT is the Forza FB-12TSD, a twelve cylinder water-cooled powerplant, capable of a variety of different fuels and being boosted by a forced induction mechanism.

At first, a six cylinder engine was considered as the powerplant, although this was discarded in favour of the twelve cylinder by Forza engineers. Twelve cylinder engines are reknowned for their superb mechanical balance, something which a six cylinder won't have without counterweights, and their relative symmetry. Another factor was reliability; should a piston fail and be lost in a six cylinder engine, one sixth of the engines power is lost which would make a sizable difference and detraction from performance. If a cylinder fails in a twelve cylinder engine, only one twelth of power lost which is a far lesser detraction from mobility.

The pistons are arranged in a boxer layout. A flat layout is near identical in appearence and theory to a boxer engine; there is still a 180 degree angle between the two seperate banks of pistons, however a boxer engine mounts two opposing pistons on two different crank pins as opposed to a flat engine which mounts two pistons on the same crank pin. Thus, a flat layout is best described as a 180 degree V engine and not a true boxer engine. Boxer engines are reknown for having superb balance and are unique in that a boxer engine does not require counter balances at all on the crank shaft as the engine has superb natural balance. This is further enhanced by the use of twelve cylinders. Boxers are so named because when one looks at the engine from down the crankshaft, the two banks of cylinders will appear to be boxing one another.

The induction system is a variant of Forza's TwinCharger system; a single Roots-type Superchager is used to aspirate the engine at low RPM's with two Turbochargers, one for each bank of cylinders, aspirating the engine further down the rev-range. TwinCharging systems have a number of advantages over other forms of forced induction. Unlike Turbocharged engines, Twincharged engines do not experience turbo-lag, where the turbochargers are ineffective because they are not at operating speeds. Unlike supercharged engines, Twincharged engines can decouple the supercharger from the engine so that it won't drain power to operate while still maintaining boost from the turbochargers. The two forms of forced induction do not operate in parallel in a bid to avoid the extremely high manifold temperatures which would be produced by the supercharger blowing into the turbocharger. As such, the supercharger is decoupled as soon as the turbocharger activates on the FB-12TSD. The TwinCharger system allows the AY1 to have constant boost and thus give exceptional acceleration at all engine speeds; something crucial for a battlefield environment.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

All up, the engine has a total displacement of 32,240 cubic centimetres or 32.24 Litres, which equates to 2.687 Litres per cylinder, and a total power output of 1500 kilowatts, which equates to a specific output of nearly 47kw per litre.

In addition to the primary powerplant, a secondary Auxiliary Power Unit is also provided. This APU is a four litre Inline four multi-fuel engine which provides 100kw of power. The APU can be used to slowly move the tank out of danger and power any high-priority electric systems should the primary powerplant fail, but is also used to provide power to move the main turret, reducing some of the strain on the primary powerplant.

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are normally ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY1 is much quieter inside and out than any other MBT.

The transmission in the AY1 is a specialized gearbox made for the tank especially. The Transmission, dubbed the 8GDCT, has eight forward gears and four reverse gears in a double clutch system. In Double Clutch Transmissions the two clutches are arranged concentrically with the larger outer clutch drives the odd numbered gears (1,3,5,7) whilst the smaller inner clutch drives the even numbered gears (2,4,6,8). Shifts can be accomplished without interrupting torque distribution to the driveshaft, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear. This means the Double Clutch Gearbox can change gears much faster than any single clutch transmission and much more smoothly. The transmission is also responsible for splitting some of the engine power from the demand for mobility to power the multitude of electronics that make up the AY1. The transmission shifts gears automatically and is programmed to keep the tank in the optimum gear for the conditions being experienced. This, when matched with the wide torque band, gives the AY1 unparalleled mobility at any given engine speed. The 8GDCT also has an overtorque function which liberates an extra 400nm from the engine, which allows the AY1 to act as a tug, pulling or pushing other vehicles (including other MBT's) out of dangerous situations.

Maximum Power: 1500kw
Maximum Torque: 6750nm (@1200rpm)
Weight (system): 5,200kg
Engine Type: Boxer 12
Displacement: 32.240 litres
Induction: Supercharger + Two Turbochargers
Fuel Diesel with Multifuel capability

Applications: AY1 MBT (Yohannes)
AY1 Howitzer (Yohannes)

[Vitaphone Racing]

Powertrain system for the AY2 Tiger MBT, produced by Yohannes

Engine: Forza FB-12TSD Flat-12 Cylinder Boxer Twincharged (Supercharger + Twin Turbocharger)
Fuel consumption: 2.1L/km
Transmission: Forza 8GDCT Automated Double Clutch Transmission, (8 forward 4 reverse)

Following the path of the heavier AY1, the primary propulsion system of the AY2 is the Forza FB-12TSD, a twelve cylinder water-cooled powerplant, capable of a variety of different fuels, and is being boosted by a forced induction mechanism.

At first, a six cylinder engine was considered as the powerplant, although this was discarded in favour of the twelve cylinder by Forza engineers. The VMK Bureau of Development and Research has previously designed its own engine designated towards the initial prototype of the heavier AY1 Serenity model. Further observation regarding Forza's apparent superiority in the field of engine development and propulsion has however altered the balance towards the proposed Forza engine considerably towards the use of the lighter AY2 project.

As a result, and under the supervision and approval of the Anago-Yohannesian Imperial and Royal Bureau of Procurement, the Forza FB-12TSD engine was chosen as the primary propulsion system of the AY2 Tiger, and all its future variants. A week passed when Forza finally finalized the deal, and the Forza FB-12TSD was chosen and selected officially as the primary propulsion system of the AY2 Tiger.

Because the FB-12TSD was designed to power a much heavier and considerably more expensive Main Battle Tank rather than the more general purpose AY2 Tiger, engineers lowered the compression ratio of the engine which would not only crop the immense power of the engine, but would also improve the fuel economy of the AY2 and the structural integrity of the engine block due to the lesser stresses being placed upon the cylinder walls. The compression ratio was lowered simply by shortening the relatively long stroke of the existing FB-12TSD powerplant by 10mm. In addition to this, the redline was lowered by 200rpm from 4500rpm to 4300rpm.

Twelve cylinder engines are known surreptiously for their superb mechanical balance, a feature which a six cylinder engines lack without the existence of counterweights and their relative symmetry. Another factor which was being put into consideration was the issue of the engine's reliability itself. If a single piston fail and/or suffered any form of major damage within the previously mentioned six cylinder engine, approximately one sixth of the engine's power will be lost.

In a crucial tactical field of operation and counting the ever progressive anti-tank countermeasure capabilities of most of the present militaries, such a blow would result as a serious blow to the performance of the armoured fighting vehicle to maintain its operation effectively within its tactical field of combat zone. As the VMK Bureau of Research and Development, together with the assistance of the Forza engineers discovered however, if a cyclinder fails and/or is damaged within a twelve cyclinder engine, only one twelfth in approximation of the engine's power would be lost, and thereby providing a far lesser detraction from the armoured fighting vehicle's overall mobility within its tactical field of operation.

The pistons are arranged in a boxer layout which is a layout seldom seen except for several high performance sports cars. A flat layout, which is more commonly seen, is near identical in appearence and theory to a boxer engine; there is still a 180 degree angle between the two seperate banks of pistons, however a boxer engine mounts two opposing pistons on two different crank pins as opposed to a flat engine which mounts two pistons on the same crank pin. Thus, a flat layout is best described as a 180 degree V engine and not a true boxer engine. Boxer engines are reknown for having superb balance and are unique in that a boxer engine does not require counter balances at all on the crank shaft as the engine has superb natural balance. This is further enhanced by the use of twelve cylinders. Boxers are so named because when one looks at the engine from down the crankshaft, the two banks of cylinders will appear to be boxing one another.

The induction system is a variant of Forza's TwinCharger system; a single Roots-type Superchager is used to aspirate the engine at low RPM's with two Turbochargers, one for each bank of cylinders, aspirating the engine further down the rev-range. TwinCharging systems have a number of advantages over other forms of forced induction. Unlike Turbocharged engines, Twincharged engines do not experience turbo-lag, where the turbochargers are ineffective because they are not at operating speeds.

Unlike supercharged engines, Twincharged engines can decouple the supercharger from the engine so that it won't drain power to operate while still maintaining boost from the turbochargers. The two forms of forced induction do not operate in parallel in a bid to avoid the extremely high manifold temperatures which would be produced by the supercharger blowing into the turbocharger. As such, the supercharger is decoupled as soon as the turbocharger activates on the FB-12TSD. The TwinCharger system allows the AY2 to have constant boost and thus give exceptional acceleration at all engine speeds; something crucial for a battlefield environment.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

In total, the engine has a total displacement of 32,240 cubic centimetres or 32.24 Litres, which equates to 2.687 Litres per cylinder. This detuned version of the FB-12TSD, with its slightly lower compression ratio, extracts a still potent 37kw per litre (10kw per litre down on the standard engine) for a total power output of 1170kw.

In addition to the primary powerplant, a secondary Auxiliary Power Unit is also provided. This APU is a four litre Inline four multi-fuel engine which provides 100kw of power. The APU can be used to slowly move the tank out of danger and power any high-priority electric systems should the primary powerplant fail, but is also used to provide power to move the main turret, reducing some of the strain on the primary powerplant.

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

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Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are normally ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY2, similar to the AY1, is much quieter inside and out than the majority of most other main battle tanks.

The transmission in the AY2 is a specialized gearbox made for the armoured fighting vehicle especially. The Transmission, dubbed the 8GDCT, has eight forward gears and four reverse gears in a double clutch system. In Double Clutch Transmissions the two clutches are arranged concentrically with the larger outer clutch drives the odd numbered gears (1,3,5,7) whilst the smaller inner clutch drives the even numbered gears (2,4,6,8).

Shifts can be accomplished without interrupting torque distribution to the driveshaft, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear. This means the Double Clutch Gearbox can change gears much faster than any single clutch transmission and much more smoothly. The transmission is also responsible for splitting some of the engine power from the demand for mobility to power the multitude of electronics that make up the AY2.

The transmission shifts gears automatically and is programmed to keep the tank in the optimum gear for the conditions being experienced. This, when matched with the wide torque band, gives the AY2 unparalleled mobility at any given engine speed. The 8GDCT also has an overtorque function which liberates an extra 400nm from the engine, which allows the AY2, similar to the heavier AY1, to act as a tug, pulling or pushing other armoured fighting vehicles (including other main battle tanks) out of dangerous situations.

Maximum Power: 1170kw
Maximum Torque: 6000nm (@1250rpm)
Weight (system): 5,200kg
Engine Type: Boxer 12
Displacement: 32.240 litres
Induction: Supercharger + Two Turbochargers
Fuel Diesel with Multifuel capability

Applications: AY2 MBT (Yohannes)

[Vitaphone Racing]

Powertrain system for the AY2-1D King Tiger MBT, AY2-1E Panthera Tigris MBT, AY2-E1 Armoured Howitzer, AY2-AVEE Engineering Tank, produced by Yohannes

Engine: Forza FB-12TSD Flat-12 Cylinder Boxer Twincharged (Supercharger + Twin Turbocharger)
Fuel consumption: 2.2L/km
Transmission: Forza 8GDCT Automated Double Clutch Transmission, (8 forward 4 reverse)

Following the path of the heavier AY1, the primary propulsion system of the AY2 is the Forza FB-12TSD, a twelve cylinder water-cooled powerplant, capable of a variety of different fuels, and is being boosted by a forced induction mechanism.

At first, a six cylinder engine was considered as the powerplant, although this was discarded in favour of the twelve cylinder by Forza engineers. The VMK Bureau of Development and Research has previously designed its own engine designated towards the initial prototype of the heavier AY1 Serenity model. Further observation regarding Forza's apparent superiority in the field of engine development and propulsion has however altered the balance towards the proposed Forza engine considerably towards the use of the lighter AY2 project.

As a result, and under the supervision and approval of the Anago-Yohannesian Imperial and Royal Bureau of Procurement, the Forza FB-12TSD engine was chosen as the primary propulsion system of the AY2 Tiger, and all its future variants. A week passed when Forza finally finalized the deal, and the Forza FB-12TSD was chosen and selected officially as the primary propulsion system of the AY2.

For the AY2-1D King Tiger, Forza engineers sought to extract extra power and torque from the existing powerplant designed for the AY1 Serenity MBT without any significant re-design of the engine itself.

The main reason for the immense power output of the Forza FB-12TSD engine is the teaming of it's high-boost forced induction system along with it's very high compression ratio. For a direct commonrail injected diesel engine, this version of the FB-12TSD posseses a ratio of 23.5:1, essentially meaning the engine compresses 2670 cubic centimetres of fuel and air mixture into 111 cubic centimetres in every cycle. The compression ratio was raised simply by extending the already long stroke of the existing FB-12TSD powerplant by 5mm. Because of this very high ratio, this called for the cylinder block to be manufactured with very thick cylinder walls in order to maintain it's structural integrity. Despite it's low displacement, the FB-12TSD weighs no less than a similarly powerful 45 litre engine although consuming much less fuel.

To further boost power, the maximum boost of the turbochargers was raised from 1.4 bar to 1.6 bar, which creates a significant increase in power when the turbochargers are active higher up the rev range, but due to the nature of a twincharger engine, makes no difference in low engine speeds due to the supercharger being the sole provider of forced induction. Combined, these two factors extract an additional 250kw over the existing 1500kw FB-12TSD engine, a 16% increase in power, for a total of 1750kw.

Twelve cylinder engines are known surreptiously for their superb mechanical balance, a feature which most types of six cylinder engines lack without the existence of counterweights and their relative symmetry. Another factor which was being put into consideration was the issue of the engine's reliability itself. If a single piston was to fail and/or suffer any form of major damage within the previously mentioned six cylinder engine, approximately one sixth of the engine's power would be lost which would have a disastrous impact on performance.

In a crucial tactical field of operation and counting the ever progressive anti-tank countermeasure capabilities of most of the present militaries, such a blow would result as a serious blow to the performance of the armoured fighting vehicle to maintain its operation effectively within its tactical field of combat zone. As the VMK Bureau of Research and Development, together with the assistance of the Forza engineers discovered however, if a cyclinder fails and/or is damaged within a twelve cyclinder engine, only one twelfth in approximation of the engine's power would be lost, and thereby providing a far lesser detraction from the armoured fighting vehicle's overall mobility within its tactical field of operation.

The pistons are arranged in a boxer layout which is a layout seldom seen except for several high performance sports cars. A flat layout, which is more commonly seen, is near identical in appearence and theory to a boxer engine; there is still a 180 degree angle between the two seperate banks of pistons, however a boxer engine mounts two opposing pistons on two different crank pins as opposed to a flat engine which mounts two pistons on the same crank pin.

Thus, a flat layout is best described as a 180 degree V engine and not a true boxer engine. Boxer engines are reknown for having superb balance and are unique in that a boxer engine does not require counter balances at all on the crank shaft as the engine has superb natural balance. This is further enhanced by the use of twelve cylinders. Boxers are so named because when one looks at the engine from down the crankshaft, the two banks of cylinders will appear to be boxing one another.

The induction system is a variant of Forza's TwinCharger system; a single Roots-type Superchager is used to aspirate the engine at low RPM's with two Turbochargers, one for each bank of cylinders, aspirating the engine further down the rev-range. TwinCharging systems have a number of advantages over other forms of forced induction. Unlike Turbocharged engines, Twincharged engines do not experience turbo-lag, where the turbochargers are ineffective because they are not at operating speeds.

Unlike supercharged engines, twincharged engines can decouple the supercharger from the engine so that it won't drain power to operate while still maintaining boost from the turbochargers. The two forms of forced induction do not operate in parallel in a bid to avoid the extremely high manifold temperatures which would be produced by the supercharger blowing into the turbocharger. As such, the supercharger is decoupled as soon as the turbocharger activates on the FB-12TSD. The TwinCharger system allows the AY2 to have constant boost and thus give exceptional acceleration at all engine speeds; something crucial for a battlefield environment.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

In total, the engine has a total displacement of 32,240 cubic centimetres or 32.24 Litres, which equates to 2.687 Litres per cylinder. This uprated version of the FB-12TSD, with its slightly higher compression ratio and increased boost pressure increased the specific output of the engine by 7kw per litre, up to 54kw/litre, which combines to form a total output of 1750kw.

In addition to the primary powerplant, a secondary Auxiliary Power Unit is also provided. This APU is a four litre Inline four multi-fuel engine which provides 100kw of power. The APU can be used to slowly move the tank out of danger and power any high-priority electric systems should the primary powerplant fail, but is also used to provide power to move the main turret, reducing some of the strain on the primary powerplant.

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are normally ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY2, similar to the AY1, is drastically quieter inside and out than the majority of most other main battle tanks.

The transmission in the AY2 is a specialized gearbox made for the armoured fighting vehicle especially. The Transmission, dubbed the 8GDCT, has eight forward gears and four reverse gears in a double clutch system. In Double Clutch Transmissions the two clutches are arranged concentrically with the larger outer clutch drives the odd numbered gears (1,3,5,7) whilst the smaller inner clutch drives the even numbered gears (2,4,6,8).

Shifts can be accomplished without interrupting torque distribution to the driveshaft, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear. This means the Double Clutch Gearbox can change gears much faster than any single clutch transmission and much more smoothly. The transmission is also responsible for splitting some of the engine power from the demand for mobility to power the multitude of electronics that make up the AY2.

The transmission shifts gears automatically and is programmed to keep the tank in the optimum gear for the conditions being experienced. This, when matched with the wide torque band, gives the AY2 unparalleled mobility at any given engine speed. The 8GDCT also has an overtorque function which liberates an extra 400nm from the engine, which allows the AY2, similar to the heavier AY1, to act as a tug, pulling or pushing other armoured fighting vehicles (including other main battle tanks) out of dangerous situations.

Maximum Power: 1750kw
Maximum Torque: 7500nm (@1200rpm)
Weight (system): 5,200kg
Engine Type: Boxer 12
Displacement: 32.240 litres
Induction: Supercharger + Two Turbochargers
Fuel Diesel with Multifuel capability

Applications: AY2-1D MBT (Yohannes)
AY2-1E MBT (Yohannes)
AY2-E1 Howitzer (Yohannes)
AY2-AVEE (Yohannes)

[Vitaphone Racing]

Powertrain system for the AY151 IFV, produced by Yohannes

Engine Forza Boxer 6 Cylinder Twincharged (Supercharged - Turbocharged) Diesel Hybrid Engine - FB-6TSDH
Fuel Consumption 0.9L/km

The FB-6TSDH engine is a diesel-electric hybrid six-cylinder boxer engine displacing only a mere 9.2 Litres yet producing nearly 500kw of power employing the Internal Comustion Engine only, and over 700kw with electric power boost. The hybrid system, Forza's own HybriDrive technology, not only ensures that the vehicle is one of, if not the, most powerful, fastest and fastest accelerating IFVs in it's class, but, when teamed small displacement internal combustion engine, also makes it one of the most fuel efficient armoured fighting vehicles ever produced.

The main reason for the immense power output of the Forza FB-6TSDH engine is the teaming of it's high-boost forced induction system along with it's very high compression ratio. For a direct commonrail injected diesel engine, this version of the FB-HTSD posseses a ratio of 23.5:1, essentially meaning the engine compresses 1540 cubic centimetres of fuel and air mixture into 63 cubic centimetres in every cycle. The compression ratio is acheived by long stroke of the existing FB-6TSDH powerplant. Because of this very high ratio, this called for the cylinder block to be manufactured with very thick cylinder walls in order to maintain it's structural integrity. Despite it's low displacement, the FB-6TSDH weighs no less than a similarly powerful 20 litre engine when one factors in the additional weight of the HybriDrive system, although consuming much less fuel.

To further boost power, the maximum boost of the turbochargers was set 1.6 bar, which creates a significant increase in power when the turbochargers are active higher up the rev range, but due to the nature of a twincharger engine, makes no difference in low engine speeds due to the supercharger being the sole provider of forced induction.

Forza engineers designed the FB-6TSDH as a six cylinder boxer, although a twelve cylinder was the preferred choice by the Anago-Yohannesian Kaissereich, simply because it allowed more space for the HybriDrive system to be fitted. The risk of a cylinder failing was more or less written off as a risk due to the presence of the battery pack and electric motors which could propel the vehicle to safety in case the worst came to the worst.

The pistons are arranged in a boxer layout which is a layout seldom seen except for several high performance sports cars. A flat layout, which is more commonly seen, is near identical in appearence and theory to a boxer engine; there is still a 180 degree angle between the two seperate banks of pistons, however a boxer engine mounts two opposing pistons on two different crank pins as opposed to a flat engine which mounts two pistons on the same crank pin.

Thus, a flat layout is best described as a 180 degree V engine and not a true boxer engine. Boxer engines are reknown for having superb balance and are unique in that a boxer engine does not require counter balances at all on the crank shaft as the engine has superb natural balance. This is further enhanced by the use of twelve cylinders. Boxers are so named because when one looks at the engine from down the crankshaft, the two banks of cylinders will appear to be boxing one another.

The induction system is a variant of Forza's TwinCharger system; a single Roots-type Superchager is used to aspirate the engine at low RPM's with two Turbochargers, one for each bank of cylinders, aspirating the engine further down the rev-range. TwinCharging systems have a number of advantages over other forms of forced induction. Unlike Turbocharged engines, Twincharged engines do not experience turbo-lag, where the turbochargers are ineffective because they are not at operating speeds.

Unlike supercharged engines, twincharged engines can decouple the supercharger from the engine so that it won't drain power to operate while still maintaining boost from the turbochargers. The two forms of forced induction do not operate in parallel in a bid to avoid the extremely high manifold temperatures which would be produced by the supercharger blowing into the turbocharger. As such, the supercharger is decoupled as soon as the turbocharger activates on the FB-6TSDH. The TwinCharger system alone allows the vehicle to have constant boost and thus give exceptional acceleration at all engine speeds; something crucial for a battlefield environment.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

In total, the engine has a total displacement of 9,240 cubic centimetres or 9.24 Litres, which equates to 1.54 Litres per cylinder. This version of the FB-6TSDH, with its high compression ratio and boost pressure creates a specific output of 54kw/litre, which combines to form a total output of 499kw. This is only the power of the internal combustion engine.

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are normally ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the vehicle, similar to the AY1 MBT, is drastically quieter inside and out than the majority of most if not all other infantry fighting vehicles.

The Forza HybriDrive replaces a normal geared transmission with an electromechanical system. Because an internal combustion engine (ICE) delivers power best only over a small range of torques and speeds, the crankshaft of the engine is usually attached to an automatic or manual transmission by a clutch or torque converter that allows the driver to adjust the speed and torque that can be delivered by the engine to the torque and speed needed to drive the wheels of the car. For classification purposes, the gearbox can be described as an Electronic Continuously Variable Transmission, or EVT.

The HybriDrive system replaces the gearbox, alternator and starter motor with a three-phase brushless alternator serving as a generator, two powerful motor-generators, a computerized shunt system to control the afforementioned devices, a mechanical power splitter that acts as a second differential, and a battery pack that serves as an energy reservoir. The motor-generator uses power from the battery pack to propel the vehicle at startup and at low speeds or under acceleration. The ICE may or may not be running at startup. When higher speeds, faster acceleration or more power for charging the batteries is needed the ICE is started by the motor-generator, acting as a starter motor.

When the operator wants the vehicle to slow down the initial travel of the brake pedal engages the motor-generator into generator mode converting much of the forward motion into electrical current flow which is used to recharge the batteries while slowing down the vehicle. In this way the forward momentum regenerates or converts much of the energy used to accelerate the vehicle back into stored electrical energy.

The sole purpose of the brushless alternator is to convert mechanical energy generated by the ICE and convert it into electrical energy which is stored in the battery pack. In addition, by regulating the amount of electrical power generated, the alternator also controls and regulates the transmission of the vehicle by changing the internal resistance of the alternator. The pair of motor generators drive the vehicle in tandem with the ICE. The two roles are not interchangeable. When the two motor generators are in operation, they create an extra 200kw of between them.

The mechanical gearing design of the system allows the mechanical power from the ICE to be split three ways: extra torque, extra rotation speed, and power for an electric generator. A computer program running appropriate actuators controls the systems and directs the power flow from the different engine and the electric motor sources. This power split achieves the benefits of a continuously variable transmission (CVT), except that the torque/speed conversion uses an electric motor rather than a direct mechanical gear train connection. The vehicle cannot operate without the computer, power electronics, battery pack and motor-generators, though in principle it could operate while missing the internal combustion engine.

The transmission contains a planetary gear set that adjusts and blends the amount of torque from the engine and motors as it’s needed. Special couplings and sensors monitor rotation speed of each track and the total torque on the tracks, for feedback to the control computer.

In summary, the HybriDrive system works by the brushless alternator feeding electric power to the battery pack where it is stored, before it is supplied to the two motor generators which rectify the electric energy into mechanical energy, where it is then used to drive the tracks. Furthermore, during normal operation the engine can be operated at or near its ideal speed and torque level for power, economy, or emissions, with the battery pack absorbing or supplying power as appropriate to balance the demand placed by the driver. During stoppages the internal combustion engine can even be turned off for even more economy.

Two other advantages are made possible by this set up.

The first is "Stealth Mode," where the vehicle can travel at slow to medium speeds without using the ICE for power, thus running silently. This gives an assaulting force an enourmous advantage as an enemy will generally not be able to hear the IFV approaching, except over rough ground which would cause noise. However, the absence of an engine note will mean that the noise of the tracks on the ground alone will not alert the enemy to the presence of an IFV. In this mode, the alternator spins freely and the engine is de-coupled from the rest of the drivetrain. Stealth Mode can be run for up to fourty minutes or fifty kilometres running off the battery power. After this, the ICE will need to recharge the battery pack.

The second is the "Overboost" function. When accelerating, the vehicle teams the powerful ICE with the pair of motor-generators to combine their power and torque, resulting in a huge boost to acceleration. The Overboost function can also be employed for the vehicle to act as a tug, by either pushing or pulling an otherwise immobile vehicle, up to an eighty tonne MBT, to a safer position.

Maximum Power: 700kw
Maximum Torque: 4000nm (@idle, electric motors)
Weight (system): 3,500kg
Engine Type: Flat 6 + Electric Generator, 2 Electric Motors
Displacement: 9.240 litres
Induction: Supercharger + Two Turbochargers
Fuel Diesel with Multifuel capability

Applications: AY151 IFV (Yohannes)

[Vitaphone Racing]

Powertrain of the Forza Corio Heavy Truck, produced by Vitaphone Racing

K-Series Diesel Engine

The Corio truck is powered by Forza's K-Series of diesel engines, a line of straight six engines of various displacement yet sharing the same core technology. The K-Series of engines were designed specifically for the Corio Class of truck and were designed to meet the market demands of United Coronado and the remaining region of Maredoratica which is tipped to be the largest market for the Corio Class. As a result, the K-Series were designed to propel the Corio trucks to highway speeds, comply with the strictest emissions laws regarding NOx emissions and offer impeccable reliability.

The K-Series feature Common rail direct fuel injection featuring very high pressure fuel rail feeding individual solenoid valves in contrast to a typical system where a low-pressure fuel pump feeds unit injectors. Common rail engines do not have to be heated up before use, produce lower engine noise and supresses the signature diesel rattle, and also produces less CO2 and NOx than other diesel engines.

The commonrail engines uses very precise piezo injectors which inject fuel rapidly at 1800 bar into the cylinder. To match the increased amount of fuel which can be pumped into the cylinder, the turbocharger aspirating the engine is electronically controlled to ensure the right amount of air is able to enter the cylinder to combust with the fuel, a process which can be summed up to yield more power in every stroke. Ceramic fast glowplugs improve the 'cold running' behaviour of the engine while two Lanchester balancer shafts enhance smoothness of operation, creating a more comfortable environment for the driver and a noticeably more refined ride experience.

The K-Series uses a Variable Geometry Turbocharger manufactured by Borg Warner. VGT's alter the geometry of the turbine housing as the engine accelerates so that the turbocharger's aspect ratio can be maintained at its optimum. The advantages of VGT's are near non-existant turbo-lag, high engine speed efficiency and a low boost threshold. VGT's are well suited to diesel engines due to the typically lower exhaust temperatures produced.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

BlueLine is Forza's brand of AdBlue diesel technology available on the K-Series of engine. BlueLine engines, in a nutshell, use their fuel more efficiently to reduce fuel consumption and emissions but create more power and torque than non-AdBlue counterparts. BlueLine engines have increased boost pressure into the engine and a slightly higher compression ratio to improve the combustion, but when exhaust gas leaves the engine, AdBlue reacts with the dangerous NOx particles that have been caught in the SCR catalytic converter to break down NOx into nitrogen and water vapour. The result in an engine in compliance with Euro 5/6 level of emission standard. AdBlue is widely available in most markets.

Across all engines, Forza offers it's EMS or Engine Management System which ties into to the Command function. EMS monitors, controls and supervises the engine, transmission and driven axles and will alert the driver if any faults or critical incidents are about to occur by monitoring such things as fuel injection, load weight and CoG, traction control and the engine brake. This system also allows the driver to adjust the settings of their truck to select the best mix between performance and economy or to select a setting which best allows for the situation they are currently experiencing.

The K780 produces 225kw and 1100nm
The K880 produces 250kw and 1400nm
The K1020 produces 298kw and 1750nm.
The K1140 produces 360kw and 2100nm
The K1480 produces 420kw and 2500nm.


The Corio offers manual and automatic transmissions that are available with varying amounts of ratios to best suit the buyer's requirements. Gearboxes ranging from five to eight ratios with high/low range capability are available for manual transmissions, while gearboxes from twelve to sixteen speed are available for automatic gearboxes.

The automatic transmission in the Corio is a specialized double clutch gearbox made for the truck especially. In double clutch transmissions, the two clutches are arranged concentrically with the larger outer clutch driving the odd numbered gears whilst the smaller inner clutch drives the even numbered gears. Gears can be selected without interrupting torque distribution to the driveshaft, by connecting the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear, this means the DCT can change gears much faster than any single clutch transmission and much more smoothly, hence minimising the time that the engine is disengaged from the wheels and allowing a smoother, less interrupted and more linear application of torque.

Maximum Power: 420kw
Maximum Torque: 2500nm (@2200rpm)
Weight (system): 1,200kg
Engine Type: Inline 6
Displacement: 14.20 litres
Induction: VGT Turbocharger
Fuel Diesel

Applications: Forza Corio Heavy Truck (Vitaphone Racing)
SR590 Bus (Mikoyan-Guryevich)
K490 Bus (Mikoyan-Guryevich)
KR500 Bus (Mikoyan-Guryevich)

[Vitaphone Racing]

Powertrain of the LR550-H Alcantara Heavy Freight Locomotive, LR575-M General Service Locomotive, LR650-S Express Passenger Locomotive produced by Mikoyan-Guryevich

The most powerful diesel engine commercially available on the market

The LR550-H is powered by a twenty cylinder opposed piston diesel with a bi-turbochager system, displacing over fifty litres and producing 4000kw. An opposed piston was selected because of its capability to employ compression ratios which are appreciably higher than those of conventional piston engines. An opposed piston engine mounts two pistons at each end of a cylinder, driving two different crank shafts. The weakest point of a cylinder block is the zenith of the cylinder; something that is missing on the opposed piston as the concave cylinder wall is replaced by another piston. Two pistons utilize the same inlet and exhaust valves.

The engine features Common rail direct fuel injection featuring very high pressure fuel rail feeding individual solenoid valves in contrast to a typical system where a low-pressure fuel pump feeds unit injectors. Common rail engines do not have to be heated up before use, produce lower engine noise and supresses the signature diesel rattle, and also produces less CO2 and NOx than other diesel engines. The commonrail fuel injector is capable of a maximum of 9 injections per combustion, injecting at up to 2000 bar in very precise amounts. Along with the three basic injections: pre-injection, main injection, and post-injection, different injection patterns will be set according to driving conditions which are controlled and governed automatically by the engine control unit.

Naturally, the compression ratio is very high, of 25:1. This is lower than other opposed piston diesels due to the use of direct fuel injection and commonrail technology. The DD020-XX can shut down 16 of its cylinders when it is at idle, leaving four remaining, resulting in much improved fuel economy for stop/start routes. Commonrail technology allows the cylinders to be re-fired almost instantaneously without an extended warming or cranking period as common with other large diesels. The engine also employs a dual stage particle filter on the exhaust, bring it into compliance with strict emissions laws.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the engine’s operative characteristics.

A special additive known as AdBlue reacts with the dangerous NOx particles that have been caught in the SCR catalytic converter to break down NOx into nitrogen and water vapour. The result in an engine in compliance with Euro 5/6 level of emission standard. AdBlue is widely available in most markets.

The engine is fitted with EMS or Engine Management System which ties into to the electronic throttle control. EMS monitors, controls and supervises the engine, transmission and driven axles and will alert the driver if any faults or critical incidents are about to occur by monitoring such things as fuel injection, load weight and CoG and traction control. This system also allows the driver to adjust the settings of their locomotive to select the best mix between performance and economy or to select a setting which best allows for the situation they are currently experiencing.

The power generated by the engine is used to drive a three-phase brushless alternator. The three phase electrical supply is rectified to DC to supply a pulse width modulator, which in turn generates a three phase electrical supply to the induction traction motors, the four traction motors being connected in parallel. Because the LR550-H is a six axle Co-Co locomotive, it uses one pulse width modulator per bogey amounting to two in total.

Pulse-width modulation (PWM) is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches.

Electrical taps from the main DC power supply also provide power to other electronically controlled power supplies including those that power the cooling fans (also known as 'blowers') at 440V 3phase 60Hz. The power supply for passenger operations (coach heating, lighting etc.) is optional and is located separately under the main frame whereas the rest of the electronic equipment is mounted in the body of the vehicle. This is available upon special request.

In addition the electrodynamic brakes can charge both a battery pack, as well as high capacity capacitors, meaning that energy absorbed on de-acceleration can be re-used later on. This feature slightly saves harmful emissions and fuel consumption, if the batteries and capacitors are full a roof mounted set of resistors provides the remainder or additional rheostatic braking. The maximum electrical braking effort is 125 kN. For additional braking a pneumatic braking system is included which can bring the total braking effort to an astounding 250kn.

Maximum Power: 4500kw
Maximum Torque: 490kN (@idle, electric motors)
Weight (engine): 25,500kg
Engine Type: Opposed 20 Cylinder + Electric Generator, 6 Electric Motors
Displacement: 52.988 litres
Induction: Two Turbochargers
Fuel Diesel

Applications: LR550-H (Mikoyan-Guryevich)
LR575-M (Mikoyan-Guryevich)
LR650-S (Mikoyan-Guryevich)

[Vitaphone Racing]

Powertrain system for the AY2-1G Serenity MBT, produced by Yohannes

Engine: Forza FB-12TSD Flat-12 Cylinder Boxer Twincharged (Supercharger + Twin Turbocharger) Ultima Ligero
Fuel consumption: 2.2L/km
Transmission: Forza 8GDCT Automated Double Clutch Transmission, (8 forward 4 reverse)

The primary propulsion system of the AY2-1G MBT is the Forza FB-12TSD-UL, a twelve cylinder water-cooled powerplant, capable of a variety of different fuels and being boosted by a forced induction mechanism. The UL variant of the FB-12TSD employs high-tech and lightweight materials in the pursuit to remove as much weight from the engine as possible.

At first, a six cylinder engine was considered as the powerplant, although this was discarded in favour of the twelve cylinder by Forza engineers. Twelve cylinder engines are reknowned for their superb mechanical balance, something which a six cylinder won't have without counterweights, and their relative symmetry. Another factor was reliability; should a piston fail and be lost in a six cylinder engine, one sixth of the engines power is lost which would make a sizable difference and detraction from performance. If a cylinder fails in a twelve cylinder engine, only one twelth of power lost which is a far lesser detraction from mobility.

The pistons are arranged in a boxer layout. A flat layout is near identical in appearence and theory to a boxer engine; there is still a 180 degree angle between the two seperate banks of pistons, however a boxer engine mounts two opposing pistons on two different crank pins as opposed to a flat engine which mounts two pistons on the same crank pin. Thus, a flat layout is best described as a 180 degree V engine and not a true boxer engine. Boxer engines are reknown for having superb balance and are unique in that a boxer engine does not require counter balances at all on the crank shaft as the engine has superb natural balance. This is further enhanced by the use of twelve cylinders. Boxers are so named because when one looks at the engine from down the crankshaft, the two banks of cylinders will appear to be boxing one another.

The induction system is a variant of Forza's TwinCharger system; a single Roots-type Superchager is used to aspirate the engine at low RPM's with two Turbochargers, one for each bank of cylinders, aspirating the engine further down the rev-range. TwinCharging systems have a number of advantages over other forms of forced induction. Unlike Turbocharged engines, Twincharged engines do not experience turbo-lag, where the turbochargers are ineffective because they are not at operating speeds. Unlike supercharged engines, Twincharged engines can decouple the supercharger from the engine so that it won't drain power to operate while still maintaining boost from the turbochargers. The two forms of forced induction do not operate in parallel in a bid to avoid the extremely high manifold temperatures which would be produced by the supercharger blowing into the turbocharger. As such, the supercharger is decoupled as soon as the turbocharger activates on the FB-12TSD. The TwinCharger system allows the AY1 to have constant boost and thus give exceptional acceleration at all engine speeds; something crucial for a battlefield environment.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 6% Scandium 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

The addition of Scandium to the alloy as well as the redesign of the external engine block to remove or redesign any parts which add any extra weight contribute for a total loss of 600kg over the weight of the previous unmodified engine, earning it the Ultima Ligero designation, Coronadan-Spanish for Ultra Light.

All up, the engine has a total displacement of 32,240 cubic centimetres or 32.24 Litres, which equates to 2.687 Litres per cylinder, and a total power output of 1500 kilowatts, which equates to a specific output of nearly 47kw per litre.

In addition to the primary powerplant, a secondary Auxiliary Power Unit is also provided. This APU is a four litre Inline four multi-fuel engine which provides 100kw of power. The APU can be used to slowly move the tank out of danger and power any high-priority electric systems should the primary powerplant fail, but is also used to provide power to move the main turret, reducing some of the strain on the primary powerplant.

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are normally ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY1 is much quieter inside and out than any other MBT.

The transmission in the AY2 is a specialized gearbox made for the tank especially. The Transmission, dubbed the 8GDCT, has eight forward gears and four reverse gears in a double clutch system. In Double Clutch Transmissions the two clutches are arranged concentrically with the larger outer clutch drives the odd numbered gears (1,3,5,7) whilst the smaller inner clutch drives the even numbered gears (2,4,6,8). Shifts can be accomplished without interrupting torque distribution to the driveshaft, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear. This means the Double Clutch Gearbox can change gears much faster than any single clutch transmission and much more smoothly. The transmission is also responsible for splitting some of the engine power from the demand for mobility to power the multitude of electronics that make up the AY1. The transmission shifts gears automatically and is programmed to keep the tank in the optimum gear for the conditions being experienced. This, when matched with the wide torque band, gives the AY2 unparalleled mobility at any given engine speed. The 8GDCT also has an overtorque function which liberates an extra 400nm from the engine, which allows the AY2 to act as a tug, pulling or pushing other vehicles (including other MBT's) out of dangerous situations.

Maximum Power: 1500kw
Maximum Torque: 6750nm (@1200rpm)
Weight (system): 4,600kg
Engine Type: Boxer 12
Displacement: 32.240 litres
Induction: Supercharger + Two Turbochargers
Fuel Diesel with Multifuel capability

Applications: AY2-1G MBT (Yohannes)

[Vitaphone Racing]

DFB-12ETDH Serie A

Introduction

The Serie A of the DFB-12ETDH is a production version of the GreenTank project engine which was not fitted to any applications. The Forza GreenTank project is a design study to create a propulsion system for an Armoured Fighting Vehicle operating where carbon-based fuel is at a premium. GreenTank uses technologies that have been pioneered on race cars, small passenger cars and diesel-electric trains to work towards a fuel consumption goal of 1.5 Litres per kilometer.

The Serie A represented several major design advantages over the GreenTank system which increased the powerplant's reliability, capability and it's performance in the field. Most crucial to this was reducing the size and weight of the battery pack which worked in tandem with the system, as the presence of the battery pack negated every packaging advantage made possible by the dimensionall small engine and also help to reduce the weight penalty that DFB-12ETDH powered tanks faced over their FB-12TSD engined counterparts.

Internal Combustion Engines

The Forza HDrive uses two internal combustion engines. Each is a Flat-6 unit displacing a relatively small 8.4 litres, forcibly inducted by Forza's eCharge aspiration system and teamed with Forza's HybriDrive technology which altogether creates the hybrid diesel-electric drivetrain.

Due to requirements to use a hybrid drivetrain, the engines needed to be kept physically small to maximise available space in order to fit the generators and battery packs required for the hybrid system. This led to the demand for a small-displacement engine which would keep external dimensions to the minimum and that would also be more efficient than a larger engine when at light load, such as speeds above idle. Maximum power produced by the ICE does not need to be as high to equal other vehicles for power to weight ratio, as the power provided by the motor generators in parallel to the ICE would be sufficient to address the diffence in power levels.

The two Flat-6 engines are stacked on top of one another to form what resembles a flat-H engine, except with no mechanical connection between the two crankshafts.

The engine has a specific output of 58 kw per litre, to put this into perspective the HDrive engine yields roughly the same amount of power per litre compared to the FB-12TSD which powers the AY2-1E Panthera Tigris MBT, one of the most powerful engines ever fitted to an MBT, despite consuming half of the fuel. The output is a product of the engine's low compression ratio, relatively high maximum engine speed and very high staged boost levels which are explained later. Each cylinder displaces 1.4 cubic centimetres. The total power of just the two ICE's alone is a mere 1008kw, much lower than the 1750kw produced by the best of the FB-12TSD series, however the hybrid system can contribute an extra 800kw to this total when the engine is at it's maximum output, giving a total output of 1808kw or over 2426 horsepower.

The Serie A version of the DFB-12ETDH extracts more power per litre than the initial GreenTank version due to increased boost setting and a re-calibrated fuel injection pattern which helps to provide maximum mechanical energy with every stroke of the piston. Improved transmission systems also mitigate the loss of power throughout the system as a whole which keeps the power at the tank's tracks almost the same as the power at the crank of the engine.

The engine block itself is made from aluminium alloy, comprised of 11% silicon, 4% manganese and 0.5% magnesium. This Al-Alloy has a high thermal conductivity and hence is able to dissipate heat quicker than cast iron. Also, it leads more thermal efficiency, cooler running engines and are lighter thereby improving the overall vehicle’s operative characteristics.

Combined with the more efficient fuel burn and the increased flexibility of the forced induction system, this drivetrain increases specific power while reducing fuel consumption.

Low Compression Ratio

The engine itself makes use of an extremely low compression ratio of 14:1, putting it on equality with the lowest compression diesel engines fitted to passenger cars and possibly the lowest ever seen on an AFV. Diesel engines generally have a very high compression temperature and pressure at piston top dead center. If fuel is injected under these conditions, ignition will take place before an adequate air-fuel mixture is formed, causing heterogeneous combustion to occur locally which essentially results in an inefficient combustion reaction.

When the compression ratio is lowered, compression temperature and pressure at top dead centre decrease significantly. Consequently, ignition takes longer when fuel is injected near top dead centre which allows for a more desireable mixture of air and fuel. This alleviates the formation of NOx and soot because the combustion becomes more uniform throughout the cylinder without localized high-temperature areas and oxygen insufficiencies. Furthermore, injection and combustion close to top dead centre result in a highly-efficient diesel engine, in which a higher expansion ratio is obtained than in a high-compression-ratio diesel engine, thus meaning the engine can produce more force with a single stroke.

Due to its low compression ratio, the maximum in-cylinder combustion pressure for this diesel engine is lower than other typical heavy diesels which allows for significant weight reduction through structural optimization, essentially lightening the engine where possible and reducing it's exterior dimensions. Because the stresses placed on the cylinder block by compression are much less than other diesels, the engine does not need to be engineered to withstand these forces and thus weight and exterior size can be shedded.

Also due to the lower combustion ratio, internal componenets such as the crankshaft were also able to be adapted due to a lesser stroke being required. This in particular reduces mechanical friction by a considerable percentage. Because the internal components and the engine block have much less stress placed upon them, they are able to last longer than components of other diesel engines, which results in not only a more fuel efficient engine but also one which is more reliable.

Cold starting and misfiring

There are only two primary problems that have been preventing the spread of low-compression-ratio diesels in modern applications regardless of their numerous advantages. The first is the fact that when the compression pressure is reduced, the compression temperature during cold operation is too low to cause combustion, which means the engine cannot be started. The second is the occurrence of misfiring during warm-up operation due to lack of compression temperature and pressure.

Forza engineers decided that the problem of a reduced compression temperature could be fixed by simply altering the amount of fuel injected when the engine is starting, thus calling for a variable fuel injection system which would be electronically controlled. The newly adopted multi-hole piezo injectors allow for a wide variety of injection patterns and can inject fuel in increments of 10^-9 of a litre and at temepratures of up to 2000 bar. Precision in injection amount and timing increases the accuracy of mixture concentration control which means the engine can start in all conditions no matter how cold the temperature is.

Ceramic Fast Glow Plugs developed by NGK also help the cold start capability. As opposed to a metal pin-type glow plug, the heating coil of a ceramic glow plug has an especially high melting point. It is also sheathed in silicon nitrite, an extremely robust ceramic material. The combination of the heating coil and ceramic sheath enable higher temperatures and extremely short preheat times due to excellent thermal conductivity. Also, ceramic glow plugs have a more compact design. This is important, because there is very little free space in today’s engines. NGK NHTC glow plugs achieve a temperature of 1,000°C in less than two seconds and can after-glow for more than ten minutes at temperatures of up to 1,350°C. Optimum combustion is ensured even at low compression ratios. In addition, the NHTC glow plug can glow intermediately to prevent cooling of the particle filter in deceleration phases.

The commonrail fuel injector is capable of a maximum of 9 injections per combustion, injecting at up to 2000 bar in very precise amounts. Along with the three basic injections: pre-injection, main injection, and post-injection, different injection patterns will be set according to driving conditions which are controlled and governed automatically by the engine control unit. Definite engine-start even with a low compression ratio is attributable to this precise injection control and also the adoption of ceramic glow plugs.

Any misfiring that may occur during warm-up operation after engine-start is prevented by adopting a variable valve timing system for the exhaust valves, similiar to the one seen on other Forza engines. From studying diesel engines, it was noted that just a single combustion cycle is sufficient for the exhaust gas temperature to rise. Given this, the exhaust valves are opened slightly during the intake stroke to regurgitate the hot exhaust gas back into the cylinder, which increases the air temperature. This promotes the elevation of compression temperature which in turn stabilizes ignition and greatly reduces if not eliminates the chance of a misfire.

Dual engine layout

The use of two seperately controlled internal combustion engines is designed to reduce the fuel consumption and emissions of an internal combustion engine during light load operation. In typical light load driving the driver uses only around a quarter to a third of an engine’s maximum power. In these conditions, the throttle valve is nearly closed and the engine needs to work hard to draw air for combustion. This causes an inefficiency known as pumping loss. Some large capacity engines need to be throttled so much at light load that the cylinder pressure at the zenith of the cylinder is approximately half that of a small engine half the size. Low cylinder pressure means low fuel efficiency and fuel consumption begins to sky rocket.

Deactivating one engine at light load means there are fewer cylinders drawing air from the intake manifold which works to increase its fluid (air) pressure. Operation without variable displacement is wasteful because fuel is continuously pumped into each cylinder and combusted even though maximum performance is not required. By shutting down effectively half of vehicle's cylinders the amount of fuel being consumed is much less. Between reducing the pumping losses which increases pressure in each operating cylinder and decreasing the amount of fuel being pumped into the cylinders. Fuel consumption for large capacity Forza engines can be reduced by 20 to 35 percent in highway conditions.

The two internal combustion engines are identical flat-6 engines designated #1 and #2 as discussed above. One engine is designated the primary engine while another is designated as the secondary; due to wear and tear issues, the designations switch automatically on the hour to ensure an adequate amount of down time for each engine.

The primary engine will operate whenever the tank is not relying on battery power for movement or to provide power to the systems which make up the tank. The secondary engine only activates on demand; ie when the primary engine can not sustain the amount of power required by the vehicle at the present time.

Each ICE is connected to a motor/generator as will be discussed later. The two engines power the generator which stores the energy created in the battery packs, relying on the remaining electric motor/generators to convert the electrical energy into motion.

Forced Induction

The GreenTank project debuts Forza's eCharge system, using electrically powered compressors to forcibly aspirate the engine rather than using exhaust powered turbochargers or mechanically driven superchargers. The eCharge system is not only more efficient than typical methods, but the lesser number of moving parts in extreme conditions also improves the reliability of the system.

Each engine mounts two compressors; one for each bank of cylinders, amounting to a total of four for this particular drivetrain. The system also mounts a total of two turbines which are used to recollect energy from the exhaust gases.

Using ultra-high voltage wires to minimize power loss, stored battery power is transferred to a series of electric motors in one of the system's compressors. There, the motors are used to accelerate the compressor to full operating speed to ensure the maximum amount of boost is available. The Forza EMS (Engine Management System) controls the air flow rate and boost pressure via control of the compressor speed which allows for a precise and effective fuel flow rate for combustion.

The compressors used are Variable Geometry Turbochargers which are well suited to diesel engines and were first used by Forza on the Corio series of commercial truck. VGT's allow the effective aspect ratio of the turbo to be altered as conditions change. This is done because optimum aspect ratio at low engine speeds is very different from that at high engine speeds. If the aspect ratio is too large, the turbo will fail to create boost at low speeds; if the aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust manifold pressures, high pumping losses, and ultimately lower power output. By altering the geometry of the turbine housing as the engine accelerates, the turbo's aspect ratio can be maintained at its optimum. Because of this, VGTs have a minimal amount of lag, have a low boost threshold, and are very efficient at higher engine speeds. VGTs do not require a wastegate.

At high engine speeds there is more energy generated by the turbine than is required by the compressor. Under these conditions, the excess energy can be used to recharge the energy storage for the next acceleration phase or used to power some of the auxiliary loads such as an electric air conditioning system.

The system can operate in what is commonly known as a 'steady state,' where the power produced by recycling the energy from the exhaust gases through the exhaust turbines matches the power consumed by the compressors. This prevents the system from draining the batteries.

Signature Reduction

Exhaust fumes and gases are passed out the rear of the tank, through a double muffler and particle filter. Exhaust gases are diluted with outside air to reduce their heat signature. This is done by sucking air through a small inlet flush against the tank and mixing the cool outside air with the exhaust gases. Exhausted and outside air meet in a special Y tube, with a radiator being mounted on the stem of the Y, sucking air from both stems through to the exhaust.

Sound-deadening engine covers are also fitted to the engine to reduce the noise both inside and outside the cabin. Forza engineers are particualrly ardent at reducing the NVH of large luxury cars but found the same basic principles applied to armoured vehicles. Double-insulated sound covers are placed in a box to cover the engine, which is itself mounted on springs to quell vibrations. The top of this box can be easily removed to lift the whole engine out. As a result, the AY1 is much quieter inside and out than any other MBT.
Hybrid Drivetrain

The Forza HybriDrive replaces a normal geared transmission with an electromechanical system. Because an internal combustion engine (ICE) delivers power best only over a small range of torques and speeds, the crankshaft of the engine is usually attached to an automatic or manual transmission by a clutch or torque converter that allows the driver to adjust the speed and torque that can be delivered by the engine to the torque and speed needed to drive the wheels of the car. For classification purposes, the gearbox can be described as an Electronic Continuously Variable Transmission, or EVT.

The HybriDrive system replaces the gearbox, alternator and starter motor with a three-phase brushless alternator serving as a generator, two powerful motor-generators, a computerized shunt system to control the afforementioned devices, a mechanical power splitter that acts as a second differential, and a battery pack that serves as an energy reservoir. The motor-generator uses power from the battery pack to propel the vehicle at startup and at low speeds or under acceleration. The ICE may or may not be running at startup. When higher speeds, faster acceleration or more power for charging the batteries is needed the ICE is started by the motor-generator, acting as a starter motor.

When the operator wants the vehicle to slow down the initial travel of the brake pedal engages the motor-generator into generator mode converting much of the forward motion into electrical current flow which is used to recharge the batteries while slowing down the vehicle. In this way the forward momentum regenerates or converts much of the energy used to accelerate the vehicle back into stored electrical energy.

The sole purpose of the brushless alternator is to convert mechanical energy generated by the ICE and convert it into electrical energy which is stored in the battery pack. In addition, by regulating the amount of electrical power generated, the alternator also controls and regulates the transmission of the vehicle by changing the internal resistance of the alternator. The pair of motor generators drive the vehicle in tandem with the ICE. The two roles are not interchangeable. When the four motor generators are in operation, they create an extra 800kw of power between them.

The two ICE are geared independantly to the EVT transmission where their power and torque is combined and then split.

The mechanical gearing design of the system allows the mechanical power from the ICE to be split three ways: extra torque, extra rotation speed, and power for an electric generator. A computer program running appropriate actuators controls the systems and directs the power flow from the different engine and the electric motor sources. This power split achieves the benefits of a continuously variable transmission (CVT), except that the torque/speed conversion uses an electric motor rather than a direct mechanical gear train connection. The vehicle cannot operate without the computer, power electronics, battery pack and motor-generators, though in principle it could operate while missing the internal combustion engine.

The transmission contains a planetary gear set that adjusts and blends the amount of torque from the engine and motors as it’s needed. Special couplings and sensors monitor rotation speed of each track and the total torque on the tracks, for feedback to the control computer.

Advantages of a Hybrid

In summary, the HybriDrive system works by the brushless alternator feeding electric power to the battery pack where it is stored, before it is supplied to the two motor generators which rectify the electric energy into mechanical energy, where it is then used to drive the tracks. Furthermore, during normal operation the engine can be operated at or near its ideal speed and torque level for power, economy, or emissions, with the battery pack absorbing or supplying power as appropriate to balance the demand placed by the driver. During stoppages the internal combustion engine can be turned off for a greater fuel economy.

Two other advantages are made possible by this set up.

The first is "Stealth Mode," where the vehicle can travel at slow to medium speeds without using the ICE for power, thus running silently. This gives an assaulting force an enourmous advantage as an enemy will generally not be able to hear the AFV approaching, except over rough ground which would cause noise. However, the absence of an engine note will mean that the noise of the tracks on the ground alone will not alert the enemy to the presence of an AFV. In this mode, the alternator spins freely and the engine is de-coupled from the rest of the drivetrain. Stealth Mode can be run for up to fourty minutes or fifty kilometres running off the battery power. After this, the ICE will need to recharge the battery pack.

The second is the "Overboost" function. When accelerating, the vehicle teams the powerful ICE with the pair of motor-generators to combine their power and torque, resulting in a huge boost to acceleration. The Overboost function can also be employed for the vehicle to act as a tug, by either pushing or pulling an otherwise immobile vehicle, up to an eighty tonne MBT, to a safer position.

The drivetrain can also be programmed to switch off the ICE and rely soley on electric power when travelling for periods of time at constant speeds to conserve fuel. Although this doesn't do much to help fuel economy during combat manuevers, a great amount of fuel can be saved when the vehicle is (not sure how to word this part, basically whenever the tank is cruising but not in an area where the speed is likely to fluctuate greatly). In a world first for a tank, the ICE is fitted with a start/stop mode which automatically kills the engine when the engine comes to idle to conserve fuel further. If the engine is still set to "on," the driver simply needs to increase the throttle and the engine will quickly restart, or the engine will automatically restart when the reserve battery power dips below 10%.

Forza EMS

Essential to the operation of the DFB-12ETDH is Forza's EMS or Engine Management System, a computer which monitors the performance of the engine and the conditions which the tank is experiencing.

The EMS for this powerplant controls which of the two ICE's will be operating at any one time and determines whether or not assistance from the non-operating ICE is needed or electric boost is needed. This is done by measuring the load of the engine at any one time and by calculating the throttle response from the driver.

EMS also controls and governs the complex commonrail fuel injection pattern of the two ICE's and also provides the computing power to run the variable valve timing system.

Ignatz-Ewald PND

Field performance of the Forza FB-12TSD utilised by that of the L variant is monitored by the Ignatz-Ewald Powerplant Network Detection (PND) system. Ignatz-Ewald PND detect engine fault and problems at the vehicle's corresponding field of tactical engagement. Its system utilised neural network to present accurate related information of the engine's components into a computerised analysis collection. The said network of neural analysis will then be used by the crew of the vehicle to analyse the likelihood of engine technical problems and performance fault which may arise at the vehicle's duration of operation.

The Ignatz-Ewald PND system is divided into that of an encoding and decoding network. PND encoding network will receive sensor information and automatically verify a primary component analysis to establish a significantly reduced space data presentation of the analysed powerplant sensor. The feature is that of a principal plural analysis towards the component.

The decoding network will then receive the input verified from the the encoding process, reconstruct the aforementioned information and calculate the output acquired from the accumulated information. In the event that a field problem and technical fault will occur towards the engine, its probability will be known by calculating the difference between the sensor-detected analysis and the de-construction process' reconstructed information.

As a result, prevention of engine fault within the vehicle's tactical field of engagement may manually be prevented, thus significantly increase the corresponding vehicle's survival rate and operational longetivity.


Maximum Power: 1808kw
Maximum Torque: 8900nm (@idle, electric motors)
Weight (system): 5,250kg
Engine Type: 2x Flat-6 Engines + 2xElectric Generator, 4x Electric Motors
Displacement: 16.788 litres
Induction: Quad Electronic Turbocharger
Fuel Diesel

Applications: AY2-1L Panthera Leo (Yohannes)

[Vitaphone Racing]

Forza Deltic

The Forza Deltic engine is the first designed by the company to take the highly unusual, rare and exotic layout that has been called the deltic for the distinctive trianglar layout of it's six cylinders. While popular in the early 50's amongst many powers and considered to be a worthy contender for future aircraft engines, the size and weight of the deltic engine as well as the development of jet engines saw it quietly dropped from planning boards until the late 50's when it was almost unheard of and discarded as a future option. Possibly the best known application of the deltic engine was an application which nobody thought it would appear, railroads. The famous British Rail Class 55 engine was powered by a 1230kw deltic engine. When first introduced, the Class 55 was designated as a high speed express locomotive on busy east coast line routes. With a service speed of 100mph, the Class 55 was certainly one of the fastest locomotives of it's day and still remains impressive even by today's standards.

The Forza Deltic is an engine again designed to serve on mainline express trains as railroad applications suit the nature of the Deltic engine far better than any other possible operation. The great size and weight of the engine doesn't matter as it simply adds to the locomotives' adhesive factor. The compactness of the design allows the engine to easily fit inside the body of the locomotive while still allowing room for the countless other systems and operations necessary to make the train run and run smoothly. While the Deltic was primarily designed for air and sea operations, the packaging of the engine only adds to the complexity and thus in the open spaces of most modern sea transports, the Deltic bore no advantage. Likewise on modern aircraft where emphasis on reducing weight is crucial, the heavy Deltic had no place in an age dominated by jets.

The Deltic engine uses six pistons shared between three cylinders per bank. Essentially, this means that a cylinder bank of the deltic engine is comprised of three opposed piston engines arranged into a triangle, with additional banks of cylinders then being added on to form the engine. This layout is demonstrated below.

http://upload.wikimedia.org/wikipedia/c ... _large.gif
Note: The bottom left input and output ports are shown incorrectly as reversed

As can be deduced from this description, the deltic engine has the advantage of being able to package a very powerful engine efficiently so that it doesn't take up as much room as what a V-layout or an opposed piston design would. The disadvantage to this however is weight with the Deltic being a very heavy engine as caused by it's frame as well as the cylinder design from the inherently heavy opposed piston layout.

As has been touched on previously, one of the core aspects to the deltic engine is the opposed piston layout, a layout seldom seen amongst smaller engines but favoured among larger marine diesels. The primary advantage of the opposed psiton engine is it's ability to deal with immensely high combustion pressures due to it's headless cylinder design. The head of the cylinder is the weakest point and is placed under considerable stress during the compression and expansion strokes of a four stroke cycle, when the forces pushing against the cylinder head and walls are at their greatest. Due to the rest of the cylinder being a perfect circle, pressure in these walls aren't felt because of the circle's ability to absorb pressure equally right around the circle, making it natures strongest shape when dealing with internal pressure. The opposed piston eliminates this problem by mounting two pistons inside one cylinder, with the piston heads pressing up against one another to achieve compression.

The deltic's unique engine layout makes terminology commonly used to describe engines difficult to understand. Forza has given the engine unique bearings to make describing it more easy. The front of the engine, distinguished by the turbine system is the "north" of the engine while the opposing end is the "south" of the engine. If one were to look at the engine from the north, towards the south straight down the crankshaft, the "west" of the engine would be on the right and the "east" would be on the left. The "Primary" cylinder which is used to describe the motion of the engine is the cylinder mounted paralell to the ground while "secondary" cylinders are mounted at a 30 degree angle to the vertical to complete the equilateral triangle shape of the engine.

Two-stroke internal combustion engines are more simple mechanically than four-stroke engines, but more complex in thermodynamic and aerodynamic processes. In a two-stroke engine, the four "cycles" of internal combustion engine theory (intake, compression, ignition, exhaust) occur in one revolution, while in a four-stroke engine it occurs in two complete revolutions. In a two-stroke engine, more than one function occurs at any given time during the engine's operation.

Intake begins when the east piston of the primary cylinder is near the "bottom" dead center or to the east point of the cylinder. Air is admitted to the cylinder through ports in the cylinder wall (there are no intake valves). All two-stroke Diesel engines require artificial aspiration to operate, and will either use a mechanically-driven blower or a hybrid turbo-supercharger to charge the cylinder with air. In the early phase of intake, the air charge is also used to force out any remaining combustion gases from the preceding power stroke, a process referred to as scavenging.

As the piston moves to the west of the engine, the intake charge of air is compressed. Near top dead center or the very middle of the cylinder, fuel is injected, resulting in combustion due to the extremely high pressure and heat created by compression, which drives the piston eastward. As the piston moves eastward in the cylinder it will reach a point where the exhaust port is opened to expel the high-pressure combustion gasses. Continued downward movement of the piston will expose the air intake ports in the cylinder wall, and the cycle will start again.

Due to the opposed piston layout of the engine, it was decided that using uniflow exhaust scaveging would be preferred. In a uniflow engine, the mixture, or air in the case of a diesel, enters at one end of the cylinder controlled by the piston and the exhaust exits at the other end controlled by an exhaust valve or piston. The scavenging gas-flow is therefore in one direction only, hence the name uniflow.

Due to the nature of the two stroke opposed piston layout of the engine, valves aren't typically be able to be controlled as they are in passenger cars as the valves are exposed by the movement of the cylinders. This means the engine is unable to hold valves closed or open to better suit the amount of air entering the cylinder. Forza combatted this by the design of their own variable valve timing mechanism to suit the engine while still allowing the valves to be opened and closed in a way normally associated with the opposed two stroke layout.

Not yet completed

For reference only: can be made available for locomotive and other very heavy vehicle purposes