Auxiliary units, such as the coolant pump, the compressor for the air conditioning system, the oil and water pump and, in passenger cars, the power steering pump, are coupled to the speed of the combustion engine with a fixed ratio. Due to the wide speed range of the combustion engine, the design of the auxiliary units cannot be optimal. It is expected that a significant increase in the efficiency of the auxiliary units can be achieved by decoupling them from the speed of the combustion engine. This would result in savings in resources such as fuel and, not least, lower emissions of the climate-damaging gas CO2.

Decoupling auxiliary units - Development of a method for improving the efficiency of drives in mobile machines by regulating the auxiliary units according to demand.

The aim of this research project is to investigate the potential for increasing the efficiency of the overall vehicle system of a mobile machine by means of demand-oriented control of auxiliary units. The determination of the power consumption of the individual auxiliary units is of decisive importance here. The investigations are intended to show at which operating points which outputs of the individual units are required in order to then regulate them according to demand and operate them with optimum efficiency with regard to the overall system.
The work at the IFKM focuses on metrological investigations on the combustion engine and the determination of the maps of the auxiliary units. Mobima contributes typical load cycles of selected machines, from which the load requirements for the engine can then be determined. In addition, the design and optimization of the new system is supported with the help of simulation technology.
The investigations carried out as part of this research project should help to make the operation of auxiliary units significantly more efficient and represent a considerable potential for fuel savings through demand-based control.