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The rapid evolution of electric vehicles (EVs) has considerably forced the automotive industry to design compact and highly efficient heat exchangers due to low-temperature applications. The plate type heat exchanger (Also known as “Chiller” in automotive industry) is one of the most important components in EVs thermal management systems. It is a type of heat exchanger, which uses metallic plates arranged like a staggered sandwiched structure and brazed together to exchange heat between two working fluids. The heat transfer between the plates occurs due to highly compact structural design as compare to any conventional heat exchangers. The chiller is having very large surface area, which is exposed to the working fluids as the distribution happens all across the plates. The chillers are more suitable design for transferring heat between ranges of working fluids pressure varying from low to high. Various types of welded, semi-welded plate heat exchangers are available in the market.

The aim of this paper is to establish the optimized control of external variable displacement compressor (EVDC) for the automotive air conditioning (AC) system in various operating modes. The control logic was developed, calibrated and experimentally verified on test vehicle. The developed control strategy ensures the stability of AC system while achieving the desired climate control and yielding the maximum possible fuel economy. The influence of cooling load, compressor speed and icing of evaporator have been investigated theoretically and validated with test data. The proposed control strategy ensures the safety of compressor and stabilizes the AC system under high engine torque demand, cold start conditions, engine shutdown or under electrical failures reported by on board diagnostics services (OBD). The results reveal improved thermal comfort and improvement in fuel economy with the use of established baseline control logic presented in the paper.