Experimental results of a novel electronic Expansion valve

Experimental results of a novel electronic Expansion valve For BEV and Hybrid Vehicles, sophisticated Thermal management Systems have been introduced. They serve several needs such as • optimal conditioning of the Battery to ensure high efficiency and lifetime, • increased operational range due to efficient heat pump operation and also • ensuring high comfort in the passenger cabin by avoiding disturbances due to very different behaviours of air conditioning profiles and simultaneous battery conditioning needs. A light weight electronic expansion valve is discussed, which can be used in natural and chemical refrigerants, providing absolutely noiseless operation at an outstanding low weight. The structure of the valve and the actuation forces enable the use in CO2 Refrigerant circuits as well. The electronic control transfers the input signal to a suitable control signal for the noiseless SMA (shape memory alloy) wire, which actuates this valve. The needle position is instantaneously measured by a Hall Sensor, having the magnet directly connected with the valve needle. The valve needle ist the only moved part in the system, leading to a high simplicity. The structure and the control behaviour of the valve in different refrigerants is demonstrated. All relevant validations have been conducted and passed successfully. Especially the excellent control behaviour, including extreme fast operation modes leads to a very simple implementation in Refrigeration and thermal management systems.