The air conditioning system is crucial for automotive thermal management. Both drivers and passengers desire comfort in their vehicles. A key function of automotive air conditioning is to regulate the temperature, humidity, and airflow within the passenger compartment to create a comfortable driving and riding environment. The mainstream principle of automotive air conditioning is based on the thermophysical principle of evaporation absorbing heat and condensation releasing heat, thus cooling or heating the cabin. When the outside temperature is low, it delivers heated air into the cabin, making the driver and passengers feel less cold; when the outside temperature is high, it delivers cooler air into the cabin, making the driver and passengers feel even cooler. Therefore, automotive air conditioning plays a vital role in cabin air conditioning and passenger comfort.
1.1 Traditional Fuel-Powered Vehicle Air Conditioning System and Working Principle Traditional fuel-powered vehicle air conditioning systems mainly consist of four components: evaporator, condenser, compressor, and expansion valve. Automotive air conditioning comprises a refrigeration system, a heating system, and a ventilation system; these three systems make up the overall automotive air conditioning system. The principle of refrigeration in traditional fuel-powered vehicles involves four steps: compression, condensation, expansion, and evaporation. The heating principle of traditional gasoline-powered vehicles utilizes the waste heat from the engine to heat the passenger compartment. First, the relatively hot coolant from the engine's cooling water jacket enters the heater core. A fan blows cool air across the heater core, and the heated air is then blown into the passenger compartment for heating or defrosting the windows. The coolant then returns to the engine after leaving the heater, completing one cycle.
1.2 New Energy Vehicle Air Conditioning System and Working Principle
The heating mode of new energy vehicles differs significantly from that of traditional gasoline-powered vehicles. Traditional gasoline-powered vehicles use engine waste heat transferred to the passenger compartment via coolant to raise its temperature. However, new energy vehicles do not have an engine, so there is no engine-driven heating process. Therefore, new energy vehicles employ alternative heating methods. Several new energy vehicle air conditioning heating methods are described below.
1) Positive Temperature Coefficient (PTC) Thermistor Heating: The main component of a PTC is a thermistor, which is heated by a heating wire, directly converting electrical energy into heat energy. PTC (Potentially Transmitted Central) air-cooled heating systems replace the traditional heater core in gasoline-powered vehicles with a PTC heater. A fan draws outside air through the PTC heater, heats it, and then delivers the heated air into the passenger compartment. Because it directly consumes electricity, the energy consumption of new energy vehicles is relatively high when the heater is on.
2) PTC water heater heating: Like PTC air heater systems, PTC water-cooled systems generate heat by consuming electricity. However, the water-cooled system first heats the coolant with a PTC heater. After the coolant is heated to a certain temperature, it is pumped into the heater core, where it exchanges heat with the surrounding air. The fan then delivers the heated air into the passenger compartment to heat the seats. The coolant is then heated again by the PTC heater, and the cycle repeats. This heating system is more reliable and safer than PTC air-cooled systems.
3) Heat Pump Air Conditioning System: The principle of a heat pump air conditioning system is the same as that of a traditional automotive air conditioning system. However, a heat pump air conditioning system can switch between cabin heating and cooling. Because heat pump air conditioning does not directly consume electrical energy for heating, its energy efficiency is higher than that of PTC heaters. Currently, heat pump air conditioning systems are already in mass production in some vehicles.
Post time: Dec-01-2025
