Compressor Control
The Compressor is directly controlled by the EMS2000 through a compressor relay.
When a request is received at the IHKS for compressor activation, a signal is sent to the BC1. The BC1 looks at blower status (output from the blower resistor pack) and evaporator temperature. If the blower is operational and the evaporator temperature is above 20°C, the BC1 changes the Compressor "OFF" signal it sends to the EMS2000 to a Compressor "ON" signal.
The Compressor "ON" signal is sent via the K-Bus through the IKE over the CAN Bus to the EMS2000. When this "ON" signal is received by the EMS2000, it checks the status of the pressure transducer, and if the transducer is in operating range (1.6 - 30 Bar) the compressor clutch relay is energized.
The BC1 is advised of the compressor activation (or no activation) and the illumination in the compressor request button of the IHKS remains illuminated. (No activation causes the LED to flash.)
Hard acceleration can cause the compressor clutch to be disengaged. After three occurrences in a single ignition cycle the ECM 2000 disregards further hard acceleration occurrences and leaves the compressor clutch engaged.
The air conditioning will be automatically suspended if:
- The engine speed is above 6016 rpm.
- The evaporator temperature falls below 2 °C - to prevent freezing.
- The coolant temperature goes above 118 °C - to protect the engine.
- The AC system pressure goes above 30 Bar - to protect the system.
- The AC system pressure goes below 1.6 Bar - to protect the system.
- The accelerator pedal is fully depressed (continuous full pedal demand) for more than 5 seconds.
- The accelerator pedal is depressed rapidly (instantaneous full pedal demand) for more than 2 seconds.
- The engine speed is below 500 rpm (engine stall).