Monitoring internal combustion engine cooling liquid circuit involves setting second error signal indicating possibility of faulty frost protection if starting temperature below freezing point

摘要

The method involves setting a first error signal if a measured engine temperature differs from a desired value from a model by more than a defined value. A second error signal is set indicating possible faulty frost protection if the starting temperature is below water freezing, a first error signal was and is no longer present after a period that is a function of starting temperature and an energy balance is introduced in excess of a threshold. The method involves comparing the measured actual value of the engine temperature with a desired value from a stored model dependent on the energy throughput of the engine and setting a first error signal if the deviation exceeds a defined value. A second error signal is set indicating the possibility of faulty frost protection if the temperature at the start is below the freezing point of water, a first error signal was present and is no longer present after a period that is a function of the starting temperature and an energy balance is introduced in excess of a starting temperature threshold.