Patent ID: 9534985
Date: 2017-01-03
CPC Classifications: F01P,G01M

Claim:
1. A fault diagnostic system for an internal combustion engine, the internal combustion engine including a cooling device having a radiator and a cooling water passage configured to circulate cooling water between the internal combustion engine and the radiator, the fault diagnostic system comprising: a first cooling water temperature sensor configured to detect a temperature of cooling water flowing in the internal combustion engine through the cooling water passage; a second cooling water temperature sensor configured to detect a temperature of cooling water flowing in the radiator through the cooling water passage; and a processor configured to: learn a first temperature difference between a detected value of the first cooling water temperature sensor and a detected value of the second cooling water temperature sensor at a first time when it is determined that the detected values of the first and second cooling water temperature sensors are stable while the internal combustion engine is at a stop; at a second time after the first time, determine a corrected temperature difference between a water temperature detected by the first cooling water temperature sensor and a water temperature detected by the second cooling water temperature sensor, wherein the corrected temperature difference is determined through use of the first temperature difference; and perform a fault diagnosis for the internal combustion engine based on the corrected temperature difference.