Determining extent of coolant underfilling in vehicle air conditioning system involves evaluating state parameter signal representing compressor switch-on time/unit time or stroke volume

摘要

The method involves determining a physical parameter constituting a measure of the load on the air conditioning system, and a state parameter representing the cooling power of the system and deriving a degree of underfilling from these parameters. The state parameter is a signal representing the switch-on time per unit time (Tein/T) of a compressor in the air conditioning system or the stroke volume of the compressor.