Method for monitoring a coolant circuit of an internal combustion engine

Abstract

The invention is based on a method for monitoring a cooling fluid circuit (16) of an internal combustion engine (10), in which an electronic control unit (42) compares a measured actual value of a temperature of the engine (10) to a desired value of the temperature, which is determined from a stored model that depends on the energy throughput of the engine (10), and the control unit (42) sets a first error signal if the deviation of the actual value of the temperature from the desired value of the temperature exceeds a predetermined amount. The invention proposes that a second error signal be set, which indicates a possible lack of antifreeze if a starting temperature is below the freezing point of water, a first error signal was present, the first error signal is no longer present after a predetermined time, which is a function of the starting temperature of the engine (10), and a built-in energy balance exceeds a threshold, which is a function of the starting temperature of the engine (10). Reference Numeral List 1 10 internal combustion engine 12 cylinder head 14 cylinder block 16 cooling fluid circuit 18 radiator 20 fan 22 heat exchanger 24 bypass line 26 regulating valve 28 return line 30 suction line 32 pressure line 34 cooling fluid pump 36 temperature sensor 38 signal line 40 signal line 42 control unit 44 characteristic field 46 display device

Dependencies are inferred from the claim text.