Contents: Communication between the air…🠛 Air Conditioning Compressor Startup…🠛 Engine Start Strategy 🠛 Overheating protection strategy 🠛
Communication between the air conditioner and the injection system ECU
The injection system ECU allows the compressor to be switched on taking into account the power consumed by the compressor and the refrigerant pressure in the circuit.
The information used for the air conditioning system is transmitted via a multiplex network:
- contact A AZ kakal CAN L multiplex network (UCS);
- contact A A4 channel CAN H of the multiplex network (UCHBS).
When the air conditioner switch is pressed, the air conditioner control panel requests permission to turn on the compressor. The injection system ECU allows or does not allow the compressor to turn on, controls the electric fan of the engine cooling system and sets the corresponding fast idle speed, which is 896 min⁻¹ for the F4P engine and 848 min⁻¹ for the K4M engine.
Caution! The refrigerant pressure and power consumption are never equal to 0, regardless of whether the compressor is on or off.
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Air Conditioning Compressor Startup Strategy
Note: In some engine operating modes, the injection system ECU prohibits the air conditioning compressor from turning on.
Engine Start Strategy
The operation of the air conditioning compressor is prohibited for 10 seconds after the engine has started.
Strategy to achieve maximum performance within a 5 second time delay.
Conditions for starting execution
The throttle valve is fully open.
Engine crankshaft speed is below 3800 min⁻¹.
2nd or higher gear is engaged.
Termination Conditions
The throttle valve is not fully open.
Or after a time delay of 5 s.
Or at crankshaft rotation speed.
Engine overspeed protection strategy.
The compressor switches off if the engine speed is higher than 6016 min⁻¹ for the F4P engine and 6500 min⁻¹ for the K4M engine.
Overheating protection strategy
The compressor does not turn on if the coolant temperature is above 115°C for the F4P engine and 119°C for the K4M engine at high speeds and under heavy engine load.