What are the effects of the two types of automobile air-conditioning compressors on fuel consumption and performance

　　Turning on the car's air-conditioning compressor will increase the fuel consumption of the engine, so how to reduce fuel consumption has become a topic that engineers need to study. The final result of the research is a variable displacement or variable compression ratio compressor, which is the air conditioning compressor of an automatic air conditioning system; this system can use AUTO mode to set the temperature to a certain standard (assuming 20 ℃), at this time, starting the engine electronic control system will default to "compressor maximum compression ratio" operation, which is the state with the highest power consumption.

　　The higher the compression ratio, the higher the speed of driving the movement of the refrigerant, the faster the cooling speed, and the faster the cooling speed in the car. After the temperature in the car reaches 20°C, the electronic control system will adjust the compression ratio of the compressor to reduce the rate of refrigerant. At this time, the intensity of refrigeration is not high, but the slight cold air can already maintain the 20°C standard in the car-constant temperature Not high-intensity refrigeration. The point is here: reducing the compression ratio of the compressor is equivalent to reducing the power consumption of the compressor. The popular explanation is that the engine drives the compressor "not tired"; the maximum compression ratio assumes that the engine needs to lose 3.5PS of horsepower, and when the constant temperature is Only need to consume 1PS horsepower, will the fuel consumption be reduced a lot?

　　The answer is obvious. It is important to save fuel and reduce emissions and improve the power experience of the vehicle. This is the important meaning of variable displacement compressors. The concept of this type of machine can be summarized by "inverter air conditioners". The fixed-displacement compressor is a "fixed frequency air conditioner". Even if the temperature is set at 20°C after turning on, the compressor will still be cooled by a fixed compressor after the temperature in the car reaches the standard, and the temperature in the car will become lower and lower. Cause discomfort. Therefore, variable displacement compressors also have the advantage of improving user experience, and constant temperature is the most ideal state.

　　So how to distinguish whether the compressor of the engine is a fixed displacement or a variable displacement? Generally speaking, manually controlled air conditioners have fixed displacement, while automatic air conditioners have AUTO mode and are basically variable displacement. There is another way to test. Turn on the A/C switch immediately after starting the vehicle in a cold car. At this time, the “full cooling” of the air-conditioning compressor will cause a substantial increase in the engine speed; however, as the temperature in the car gradually decreases, compression The constant change of the compression ratio of the engine will reduce the power consumption and the engine speed will decrease synchronously. The variable displacement compressor will experience a drop in idle speed, while the fixed displacement compressor will not change. This is the difference.