Integrated pulley gearbox for auxiliary units

Project name

Integrated belt pulley transmission for auxiliary units

Project duration

01.08.2006 - 30.11.2007

Brief description

Developments in the automotive industry are aimed at both compliance with future emissions legislation and a further reduction in fuel consumption and thus CO2 emissions. The commitment of European vehicle manufacturers to achieve a fleet consumption of 140g CO2/km by 2008 and 120g CO2/km by 2012 represents a major challenge. In addition to improving the combustion engines, a major focus is on system optimization in the operation of auxiliary units such as water pumps, generators, air conditioning compressors and hydraulic pumps (steering assistance, roll stabilization). Depending on the operating state, the energy consumption for driving the auxiliary units in the vehicle is 10 percent or more of the energy required to drive the vehicle. The auxiliary units are generally designed to deliver a high output even when the combustion engine is idling. The energy requirement of the auxiliary units must already be covered at this speed in order, for example, to air-condition the vehicle even when stationary, to charge the battery and to provide sufficient steering assistance (parking). However, this design leads to poor efficiency at higher engine speeds and low auxiliary unit loads. One approach to reducing these losses is to switch from mechanically driven auxiliary units to electrically driven auxiliary units. Although these auxiliary units do not consume any energy when they are not needed, they have a significantly poorer energy balance under load, as the efficiencies of the generator and electric drive are multiplied (around 10% to 70% each). Further disadvantages of electrically driven auxiliary units are the high costs (motor drives, control), additional mass and larger installation space. In contrast, the mechanical drive (belt drive) has an overall efficiency of well over 90%. By integrating a switchable mechanical gearbox, the speed of the auxiliary units can be adjusted as required, thereby achieving a significant consumption advantage. As part of the project, a minimum two-stage transmission integrated into the pulley of auxiliary units is to be developed, which will be tested and optimized under practical conditions on the highly dynamic engine test bench at TU Dresden. The aim is to achieve a significant fuel consumption advantage.

Cooperation partner

• MBM Maschinen- und Metallbau GmbH & Co KG, - (Germany)

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