Press the "A/C" button and "Blower" button of the air conditioner at the same time, or press the "Automatic Control" button, the air conditioner ECU will engage the electromagnetic clutch and the compressor will start to work. The MGC terminal of the air conditioner ECU first sends a compressor working signal to the engine ECU, and the A/C MG terminal of the engine ECU is grounded immediately, so that the magnetic suction relay is pulled in, and the current flows into the magnetic suction to make the compressor run. At the same time, the current is also added to the A/C end of the air-conditioning ECU, and the magnetic suction work signal is fed back to the air-conditioning ECU.
During automatic control, if the ambient temperature or the evaporator temperature drops below a certain value, the air conditioner ECU will control the compressor to work intermittently, that is, the magnetic attraction turns on and off alternately to save energy.
When the air conditioner is working, the air conditioner ECU simultaneously collects the engine speed and compressor speed signals from the engine igniter and the compressor speed sensor, and compares them. If the deviation rate of the two speed signals exceeds 80% for 3s in a row, the ECU will determine that the compressor is locked, and at the same time disengage the electromagnetic clutch to prevent further damage to the air conditioner; and make the A/C indicator on the control panel flash to remind driver.
.png)
