On-Board Diagnosis of Vehicles Cooling System

On time recognition of vehicle cooling system faults prevents excessive air pollution and un-compensable engine damages. Lack of water, pump defect, thermostat malfunction, fan system failure and radiator clogging are among the most common types of faults; some of them are so critical that must be fixed immediately. In this paper, a diagnostic algorithm based on isolating of the cooling system fault from engine functioning is introduced, where the measurable engine body temperature stands for the most of the combustion parameters and their uncertainties. The fault isolation is also partially accomplished by introducing three distinctive temperature zones. An engine thermal simulator, which mimics a real engine, generates both nominal and faulty system states considering complete engine and cooling system tolerances. Extensive simulations are conducted for determination of the fault thresholds and certification of the validity of the algorithm.