New energy vehicle air conditioning system
There are differences in system composition between new energy vehicles and traditional vehicles, and different types of new energy vehicles have different characteristics. As far as pure electric vehicles are concerned, there is no engine as the power source for the air conditioning compressor, and it is impossible to use the engine waste heat to achieve heating and defrosting effects. For hybrid vehicles, the engine cannot be used as a power source for refrigeration and compression or a heat source for heating at any time due to its control strategy. Therefore, the air conditioning systems of the two are not exactly the same.
In principle, the air conditioning system of new energy vehicles is basically the same as the air conditioning system of traditional fuel vehicles. The difference is mainly reflected in the driving method of the air conditioning compressor and the source of warm air. New energy vehicles currently generally use electric compressors for refrigeration, and high-voltage electric air conditioning compressors are driven by power batteries. Electric vehicle heaters usually use electric heating. There are two electric heating methods: one is to heat the coolant and then circulate it to provide heat to the hot water tank (currently the mainstream); the other is to directly heat the evaporator through the evaporator. The air achieves warm air. For strong hybrid vehicles, the source of warm air uses engine coolant as the heat source when the engine is working; in EV mode, electrically heated PTC is generally used to provide the heat source.
New energy vehicle air-conditioning systems generally use electric air-conditioning compressors for refrigeration. The refrigeration principle is the same as that of traditional vehicle air-conditioning, which will not be described here. It is worth mentioning that the cooling of high-voltage batteries on many models now also removes heat through air-conditioning pipelines.
Heating is more complex and critical for new energy vehicles, because the warm air heat source of the air conditioning system of fuel vehicles is mainly provided by engine coolant, which consumes almost no power, is relatively simple and very efficient. But it is more troublesome for new energy vehicles, so an extra PTC heater is usually installed to complete the heating function. The PTC heater can be simply understood as a large resistor. When current passes through Q=I2R, heat is generated. The problem is that the thermal efficiency is low and the energy consumption is large. In extreme cases in winter, the power consumed by the electric air conditioner is half the vehicle's cruising range. Therefore, many drivers dare not turn on the air conditioner in winter, which is why new energy vehicles need to bring warm babies with them in winter. What is worth looking forward to is that heat pump air conditioners are attracting more and more attention due to their high heating efficiency. At present, major OEMs are actively conducting relevant research and development, and a small number of mass-produced models already have heat pump air conditioners.
