Electric Vehicle, Scroll Compressor, Numerical Simulation, Efficiency Study
With the development of electric cars the cooling and heating of the passenger compartment is even today a major challenge for the automotive industry. Apart from the passenger compartment, the A/C system in today’s electric vehicles cools and heats auxiliary devices like the battery and the power electronics. The high demand of heating and cooling power leads to a significant reduction in cruising range. In the A/C systems of electric vehicles, electric driven scroll compressors are widely used. These compressors have several advantages compared with axial piston compressors used in conventional cars, e.g. easy controllability as well as good efficiencies at high speeds. However, there are also some disadvantages like the higher production costs. Apart from these two mentioned compressor types, other compression principles are rarely investigated for the use in electric vehicles. Therefore, this contribution compares and evaluates different compressor types for this application, e.g. scroll, axial piston, rotary piston and radial piston compressors. The benchmarks are aspects like the mass flow rate, the pressure pulsation, the torque fluctuation and the compressor efficiencies at different operating conditions. The contribution starts with a short overview of the specific requirements for refrigerant compressors in electric vehicles. Then the mentioned compressors are investigated in detail on the basis of geometric and physical based numerical simulation models. Moreover, their influence on the entire A/C circuit is presented, followed by an evaluation by means of a main vehicle model for different driving cycles and environmental conditions. The paper closes with some recommendations for the application of the compressors as well as future development concepts.