Two main output temperature control methods and their characteristics
At present, the mainstream automatic control mode of air conditioning system, there are two main types in the industry: automatic control of mixed damper opening and variable displacement compressor adjustment mode.
Automatic control of the opening of the hybrid damper
"The method of automatically controlling the opening of the mixing damper" is to use the mixing damper to mix the cold air on the evaporator side with the warm air on the core side to output a compromise temperature. The defects of this control mode are as follows:
1. Frequent on-off of compressor has a great impact on the stability of engine output power.
2. Continue to work in the excessive refrigeration state, in order to offset the low air temperature caused by strong refrigeration, the warm air needs to be mixed with it, in fact, resulting in a large waste of power.
3. The temperature control damper of automatic air conditioning needs to be adjusted continuously during use, which requires very high durability and high motor failure rate.
Adjustment mode of variable displacement compressor
"Variable displacement compressor adjustment mode" is through the variable displacement compressor displacement change control, to achieve the change of cooling capacity output. Its problems are mainly reflected in the high cost of variable displacement compressors, and it is difficult to carry out automation system transformation for basic models that are not equipped with automatic control air-conditioning systems.
Variable temperature control mode characteristic description
The technical problems to be solved by "variable temperature control mode" are: Provides a temperature control logic calculation method, which does not increase any cost on the basis of traditional air conditioning system, only through the control means of compressor, to achieve more energy-saving temperature control and avoid the compressor to work in the inefficient excessive refrigeration interval for a long time. It reduces the number of compressor on and off, when the refrigeration is sufficient, by appropriately increasing the compressor cut-off temperature read by the evaporator surface temperature sensor, the purpose of appropriately increasing the evaporator surface temperature is to achieve the purpose of appropriately increasing the evaporator surface temperature, rather than using the hot air to mix the cold air like the traditional automatic air conditioning risk control method, so as to reduce the fuel consumption waste of the automobile air conditioning system in the working condition without full load.
Control input
In order to achieve the above purpose of "low cost, high performance and lower energy consumption", the following technical solutions are adopted to control the cut-off point of the compressor with variable temperature. Its main signal inputs are as follows:
The outdoor temperature is read by the outdoor temperature sensor;
Read the room temperature by the room temperature sensor;
The sunlight intensity is read by the sunlight intensity sensor;
Evaporator temperature sensor reads the evaporator surface temperature;
The vehicle bus network provides engine and vehicle signals such as engine water temperature and vehicle speed to compensate for subsequent calibration.
Closing remarks
Variable temperature control air conditioning system for the air outlet adjustment mode is to control the compressor operating temperature range to make the evaporator surface temperature output a temperature similar to the required temperature. During this whole process, the mixing damper is fixed in the coldest position, no warm air mixing.
Post time: Oct-07-2023