Section 3 A/C Controlling System - Geely CK Series 2007 Workshop Manual

I. Introduction and Composition
In order to ensure the effective opeation of the A/C system in any operating condition, some advanced
electric control devices are used to protect the A/C system in adverse engine operating condition.
The electrical control part consists of: A/C switch, relay, evaporator temperature sensor, water temperature
sensor, pressure switch, ECU...etc.
A/C system circuit diagram is shown in Figure 6.
II. controlling system feature
(1) The condenser fan's power is 90W;
(2) The performance of the condenser fan is controlled by ECU, pressure switch;
(3) Cut off the electrical power of the A/C compressor clutch when the water temperature reaches 109°C;
(4) Connect blower switch 9 to rotate the blower motor 6 to ensure A/C normal operation. Connect A/C
switch 10 to output A/C request signal to ECU.
(5) After ECU receives the request signal and the one from the evaporator temperature sensor 17, if the
engine is at idle, ECU first increases the engine speed to 950 ± 50r/min, lest the A/C operation enhance
the load and lower the engine speed or result in engine off. And then the ECU can respond. If the engine
is in accelerating condition, ECU does not respond immediately either, and respond 5 seconds later after
the end of the accelerating condition. ECU send out a A/C control signal from pin 22 to relay 7, command
the relay to suction in. With the low pressure switch 11 closed, the compressor 12 starts to work when the
magnetic clutch suction on. The condenser relay holds in and condenser blower 13 rotates. When high
pressure switch 15 is closed, have the relay 7 hold in and the water tank fan 14 rotates. When the water
temperature sensor 16's temperature is higher than 109°C, ECU shut off the output signal of the pin 22
and A/C stops operation.
(6) When the Refrigeration system pressure is over 1.7MPa, radiator fan will rotato. Disconnect A/C
compressor Refrigeration system power supply when the pressure is over 2.6MPa or less than 0.25MPa;
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Section 3 A/C controlling system