Patent ID: 6804588
Filing Date: 2004-10-12
Classification: F01P

Abstract:
A system for discriminating malfunction of a radiator having an inlet pipe connected to an internal combustion engine and a thermostat fitted in the inlet pipe to open the inlet pipe to pass engine coolant in the radiator to cool, comprising:engine operating condition detecting means for detecting operating conditions of the engine including at least an outside air temperature and a coolant temperature; outside air temperature decline amount calculating means for calculating a decline amount of the detected outside air temperature since starting of the engine; malfunction discrimination execution condition establishing deciding means for comparing the calculated decline amount of the detected outside air temperature with a threshold value and for making a decision that conditions for execution of malfunction discrimination of the radiator are established, when the calculated decline amount of the detected outside air temperature is less than the threshold value; estimated coolant temperature calculating means for calculating an estimated coolant temperature based on at least the detected coolant temperature and a thermal load parameter contributing to coolant temperature rise, when the malfunction discrimination execution condition establishing deciding means makes the decision that the conditions are established; and malfunction discrimination executing means for comparing the estimated coolant temperature and the detected coolant temperature with predetermined values and for discriminating whether the radiator has malfunctioned based on results of comparison; wherein the improvement comprises: malfunction discrimination execution condition non-establishing preventing means for preventing the malfunction discrimination execution condition establishing deciding means from making the decision that the conditions are not established, utilizing a parameter related to a quantity of intake air.