mtu develops new MT 890 heavy-duty engine

• Diesel electric version 50% lighter and smaller than current engines
• Common rail injection ensures efficient combustion
• Hot cooling reduces the volume of the cooling system
• Flexibility for installation
• High availability due to low maintenance requirement

Paris - MTU Friedrichshafen is currently developing a new engine range, MT 890 (HPD - High Power Density) for armored vehicles. The "890" engines will achieve an unprecedented power to size ratio and therefore be particularly small and light. The company is planning to cover the output range of 550 to 1470 kW (750 to 2,000Hp) with five different cylinder variants (6V - 16V). By increasing the output and reducing the size of the components of the drive system, it has been possible to maximize the power to size ratio of the entire drive. In comparison with the 12V MT 883 engine for armored vehicles in the same power category, the diesel electric version of the 12V MT 890 will attain a reduction in weight and volume of approximately 50%. The lowest possible power/weight ratio will be 0.81 kg/kW and the power-to-bulk-volume ratio an unprecedented 1,360 kilowatt per m3. This extraordinary compactness is produced primarily by reducing the basic engine, the cooling system and other characteristic subsystems. A particularly efficient exhaust-gas turbocharger, high engine speed and above all a highly integrated design contribute significantly to the reduction of the volume of the basic engine. For example, the oil filters, oil heat exchanger, dry sump and air manifolds are integrated into the crankcase. A considerable reduction in double walls and bolted connections is thus achieved. The crankcase has an extremely compact and rigid design and its weight is optimized by the aluminum construction.

Common rail injection ensures efficient combustion

The new engine range, MT 890, is fitted with a common rail high-pressure injection system. The procedure allows all injection parameters to be set as required and flexibly adapted to the respective operating conditions. The timing, duration and course of the injection and the level of the fuel pressure can be defined as required. Therefore, unlike engines with conventional injection systems, high injection pressures are also available at low engine speeds, allowing efficient combustion in this operating range in particular.

Hot cooling reduces the volume of the cooling system

The weight and volume of the cooling system have also been considerably reduced. This is made possible by the use of a dual-circuit cooling system and by increasing the maximum coolant temperature. The maximum permissible coolant temperature in the basic engine is thus approximately 20 °C higher than in previous mtu engines for armored vehicles. This technological milestone means that the temperature equilibrium in the basic engine is improved and the flow of heat into the coolant is therefore smaller. This allows a considerable reduction in the volume of the cooling system. In terms of cooling, the high temperature of the coolant in relation to the ambient air ensures that there is a significant drop in temperature.

The cooling system consists of a high temperature and low temperature circuit and therefore makes better use of the available cooling capacity. In addition, low temperatures can be achieved for those components for which it is necessary in the cooling circuit. The high temperature circuit therefore achieves a high cooling capacity in a small space. Despite a relatively low cooling capacity, the low temperature circuit produces low temperatures in the charge-air cooling tract.

Flexibility for installation

The extremely compact design of the basic engine with options for connecting charge air and exhaust gas to both ends of the engine offers considerable flexibility with regard to installation in the respective vehicle. The vehicle manufacturer is therefore given as much design freedom as possible. The MT 890 can be installed in the engine compartment longitudinally or transversely, and the arrangement of the peripheral components such as the cooling system and the air filter system is also flexible. Due to the compact design, it is also possible - if required - to use two six-cylinder engines instead of one twelve-cylinder engine, for example.

The new MT 890 engine range is equally suitable for Diesel-electric and conventional transmissions. Extremely high flexibility is achieved in installation by using a Diesel-electric drive. New drive concepts are expected in future, especially for military vehicles, as a result of electric drives in particular. For wheeled vehicles, it is expected that the electric motors will be incorporated into the wheel hubs. For crawling, for example, electric motors allow almost silent vehicle movement, "silent watch". However, the MT 890 is also suitable for conventional drives. In these drives, it has sufficient high torque rise for the drive to qualify as a mechanical drive.

High availability due to low maintenance requirement

In contrast to other engines for armored vehicles in the same power category, the mtu heavy-duty engine, MT 890, has the significant advantage of a low maintenance requirement. Topping up the lubricant and coolant is the only regular check required. A major overhaul is not required until after 1500 operating hours. These advantages are achieved through hydraulic valve clearance compensation, an auto-cleaning air filter and the extremely compact design, thanks to which a significantly reduced number of interfaces is required. The absence of maintenance not only saves time and money, but also increases the availability of the vehicles.