The new Series 890 Diesel Engine: Top performance through new, patented design

• Highly integrated engine
• Key technologies: injection, turbocharging and electronics
• Systems Engineering: PowerPack includes a number of subcomponents

Washington - The new Series 890 engine introduced at the AUSA annual meeting in Washington represents a quantum leap in diesel engine technology. With 0.60 kg/hp and a 1848 hp/m3 it is the most powerful diesel engine series in the world in terms of power-to-weight and power-to-volume ratio. Key to the high performance at low weight and small size is a new, patented design of the engine, combined with high engine speeds and high pressures. Various parts of the engine which have normally been located at the outside of the engine are now integrated in the crankcase thus making the engine smaller and lighter. The entire dry sump oil system, including oil volume, oil pumps, oil heat exchangers, oil filter and oil ducts, is now integrated in the crankcase. All free spaces at the sides of the crankcase have been used to insert components of the oil system or oil. The oil pan itself is very flat and contains only a minimum of oil. It is made of cast aluminum and integrates all necessary piping for the different oil flows so that no extra tubes are necessary. The air intake manifolds are integrated in the crankcase as well, which is made of a specially treated, hardened and very rigid aluminum.

Unusual for engines of that size are the high speeds and the high pressures utilized. HPD runs at maximum 4250 rpm, double the speed of truck engines. The mean effective pressure, with many diesel engines no higher than 20 bar, reaches 26 bar for the Series 890. A high temperature engine cooling system working at up to 266 °F (130 °C) makes sure that the components of this system remain small.

Key technologies: injection, turbocharging and electronics

The Series 890 is the fourth generation of mtu combat vehicle engines and includes various of the tried-and-true technical solutions of existing modern diesels. These technologies are being applied on the Expeditionary Fighting Vehicle's engines (EFV / AAAV), have been tested and are of low risk. Among them are common rail injection, powerful turbocharging and an advanced electronic engine management. They are a precondition to high performance, low fuel consumption and low emissions.

The Common Rail injection system of the Series 890 has very successfully been employed on mtu's Series 880 tank engines as well as on the company's commercial engine series 4000 and 8000. Up to now, DaimlerChrysler Off-Highway has sold nearly 7000 engines with this system. The Common Rail injection employed on the Series 890 engines builds up pressures of 1800 bar, a prerequisite for efficient combustion. The system allows all fuel injection parameters that affect fuel combustion to be independently controlled. That includes variables such as timing, the period and the pattern of injection as well as injection pressure. This is a decisive advantage when it comes to reducing fuel consumption and exhaust emission levels - and not just at a specific running speed but across the entire power curve.

The Common Rail injection system of the Series 890 has very successfully been employed on mtu's Series 880 tank engines as well as on the company's commercial engine series 4000 and 8000. Up to now, DaimlerChrysler Off-Highway has sold nearly 7000 engines with this system. The Common Rail injection employed on the Series 890 engines builds up pressures of 1800 bar, a prerequisite for efficient combustion. The system allows all fuel injection parameters that affect fuel combustion to be independently controlled. That includes variables such as timing, the period and the pattern of injection as well as injection pressure. This is a decisive advantage when it comes to reducing fuel consumption and exhaust emission levels - and not just at a specific running speed but across the entire power curve.

The electronic engine management CDS (Control and Diagnostics System) has been developed and manufactured by mtu and is an integral part of the engine. It has been designed in a way which provides optimum interfaces to the different components of the engine. CDS contains the controlling, governing and monitoring functions for the engine. A diagnostic function of the electronics explains when, why and how a failure occurred, an optional prognostic function provides information about the expected future status of the engine and its components. One of the electronics functions is to temporarily reduce the power of the engine in case of irregularities and shut down the engine altogether if this is necessary to prevent major damage. An override function is provided for emergencies. Finally, CDS allows the integration of the Series 890 into PowerPacks. There are interfaces to all components of complete drive systems.

The turbochargers of the Series 890 have - like those of many other mtu engine series, too, - been specially developed and are being manufactured at the company factory. They build up air pressures of 1:4,5 and push up the power output of the engine considerably. With a flexible turbine geometry, they raise torque at low engine speeds and improve fuel consumption. At part load, the fins inside the inlet part of the turbine partially close and push more pressurized air into the combustion system.

Systems Engineering: PowerPack includes a number of subcomponents

One of the strengths of mtu and DDC is the ability to build complete PowerPacks. This know-how is equally being applied to the FCS drive system. The PowerPack for FCS consists of the engine, a starter/generator to produce the energy for the electric drive motors, power electronics, a cooling system and an efficient air filtration system. Here an efficient pre cleaning system is used and a fine filter further down the air stream. It is self cleaning without using moving parts. mtu has had many years of experience with such PowerPacks and uses this design principle in a wide range of vehicles, military and non-military.

Technical Data of the FCS 6V 890 Diesel Engine

Number of Cylinders	6 in a 90 degree Vee
Bore	4.29 inches
Stroke	4.21 inches
Displacement per cylinder	3,66 in3
Power at rated speed, maximum	750 hp at 4250 rpm
Torque, maximum	1235 Nm at 4250 rpm
Injection system	Common Rail
Max. Injection pressure	1800 bar/26.125 psi
Weight (dry)	470 kg
Dimensions (height x width x length)	22.8 in. x 27.6 in. x 34.8 in. / 590 mm x 700 mm x 760 mm