The development of energy efficient air conditioning systems for electric vehicles is an ever increasing challenge, because the cooling as well as the heating of the passenger compartment reduces the cruising range dramatically.
Electric cars are usually equipped with a scroll compressor and a separate electric motor with appropriate power electronics. However, this solution is critical in terms of the installation space, the weight and also the costs. Therefore, an innovative and energy efficient drivetrain structure for electric vehicles was developed, which integrates the motor of the A/C-compressor directly into the drivetrain.
Thus it is possible to switch off the compressor motor and to use the main motor for the drive of the compressor at certain driving situations. As a result, the operating point of the main motor can be shifted to a better efficiency. Moreover, in urban traffic the compressor motor can be used to drive the vehicle if the efficiency of the compressor motor is higher than the efficiency of the main motor. Thereby the efficiency and the cruising range of the vehicle can be increased.
This contribution presents a new powertrain concept which realizes the above mentioned mechanical coupling of the main motor and the compressor motor. This new concept is compared with a standard electric car which is equipped with a separate scroll compressor. Both systems are evaluated by means of the achievable cruising range for different driving cycles and environmental conditions.