ERL (Energy Requirement Level)

Main status variable Energy Requirement Level (ERL)
When the air-conditioning system is in a regulated operating state, all of the control functions of the system are dependent on this ERL status variable.

The main status variable used to determine the thermal energy requirements in the vehicle (the EPL signal) is derived from the most important parameters:
- Nominal temperature of the passenger compartment
- Actual temperature of the passenger compartment
- Ambient temperature
- Solar radiation energy.

The status variable ERL varies across the digital range .... 255 (8 bit).

This corresponds to the extreme cases max. cooling requirements and max. heating requirements.

In special cases, e.g. climate controller start-up, cold/warm-start of the vehicle, the parameters coolant temperature and vehicle cycle time are used to adjust the regulating and control functions.