Mahle Behr

In diesel engines, steel pistons provide significant potential for reducing CO2 emissions in comparison with the aluminum pistons that have been typical up to now. After a long history of positive results in commercial vehicles, MAHLE has therefore developed steel pistons for passenger car diesel engines to the point of series production readiness. Significant advantages result from the frictional loss. Thermodynamic conditions additionally result in advantages in combustion that lead to a reduction in fuel consumption and emissions levels. The lower compression height of a steel piston can also be utilized to increase the swept volume or to decrease the height of the engine.

Critical package constraint situations present a formidable challenge to the development of air filters for commercial vehicles. MAHLE air filter modules are individually customized according to customer requests with regard to package constraint, weight, and interfaces to other systems. Another development focus of MAHLE is on achieving long maintenance intervals. Mechanical and electrical sensors reliably display the maintenance status of the filter system. The filter is freely accessible and tool-free maintenance is possible.

Fuel management in commercial vehicles is mainly governed by fuel preparation, i.e., filtration and water disposal. The trend toward a so-called world engine, or engine platform for use in every region of the world, gives rise to considerable technical challenges. On the one hand, the engine must meet the partly strict exhaust gas legislation, which leads to a high level of technological advancement. On the other hand, it is this sophisticated level of technology that is confronted with different biofuel shares and fuel quality levels. It is therefore necessary to enable optimal separation of contaminants and water even under these conditions.

MAHLE fuel injection systems match the fuel quantity and timing to the specific operatingload condition so that the engine delivers the required performance, coupled with low emissions and low consumption. The MAHLE system comprises the electronic control unit, sensors, fuel pump, injectors, and throttle valve. MAHLE fuel injection systems are available in a battery-powered or battery-free concept.

One approach to meeting the new NOx (nitrogen oxide) emissions limits is to incorporate cooled exhaust gas recirculation (EGR). This involves extracting a portion of the main exhaust flow between the engine outlet and the turbine, cooling it in a special heat exchanger, and feeding it back to the intake air downstream of the charge air cooler. The combustion temperature in the engine is thereby lowered, thus reducing the formation of NOx. Our EGR coolers offer exceptional thermomechanical strength, reduced tendency to sooting, and outstanding specific performance. Thanks to the use of high-performance winglet tubes, extremely stable EGR temperatures—and thus improved EGR control—can be achieved.

Thanks to re-engineered geometries and enhanced manufacturing processes, we have succeeded in keeping the weight of the new air-cooled EURO 6 charge air cooler constant, in spite of larger cooling surfaces and significantly improved component robustness and durability. Performance density was increased at the same time. The charge air coolers also reduce the installation depth of the cooling module by a further 14 mm, hence optimizing air flow throughout the system. As a result, the power requirement of the fan can be reduced without impairing cooling performance. Furthermore, new design measures must accommodate the increasingly higher thermal and pressure loads that charge air coolers are subjected to. Indirect charge air cooling systems use extremely compact coolers that are cooled by the coolant of the separate low-temperature cooling circuit. Since the low-temperature radiator has a large front surface and is swept by the cold cooling air flow, very low charge air temperatures can be achieved. Due to their superior efficiency (as compared to a charge airair cooler), they can be designed with very compact dimensions and mounted onto the engine. In transient driving conditions, they provide for a much more stable intake air temperature and thus help reduce fuel consumption.