| 摘要 |
Provided is a diagnosis device which effectively diagnoses coolers without providing a temperature sensor upstream of the coolers. A diagnosis device for coolers (16, 22) for cooling fluid flowing through the intake and exhaust systems (11, 12) of an engine (10) comprises: downstream temperature sensors (34, 37) for detecting fluid temperature downstream of the coolers; fluid temperature calculation units (42, 52, 53) for calculating fluid temperature upstream of the coolers on the basis of a fluid state quantity; sensor output value calculation units (44, 54) which assume upstream temperature sensors detecting fluid temperature upstream of the coolers, reflect a delay in sensor response in the calculated fluid temperature, and calculate estimated sensor output values from the upstream temperature sensors; and cooler diagnosis units (45, 55) for diagnosing the cooling efficiency of the coolers on the basis of actual sensor input values inputted from the downstream temperature sensors (34, 37) and on the basis of the calculated estimated sensor output values. |
