Abstract
Keywords Critical, points, engine, cooling, systems.
Abstract - In this study a practical methodology to find the most critical points in a vehicle engine cooling systems is proposed. The criterion to define these critical points is based on the radiators coolant inlet temperature and engine oil temperature. Three vehicles of different engine characteristics where tested on a wide set of operating points and conditions during the present study.
Results indicate that the most critical points, those of higher coolant and engine oil temperatures, are present at high regimes in low gears; that their values become more critical as the ambient temperature raises and also that as we shift to upper gears the number of critical points is lessened.
It was also noticed that as the vehicle speed is increased without shifting gears the coolant and engine oil temperatures increase, meaning that even if the airflow to the radiator and coolant flow are increased the effect of augmenting the heat generated by the engine is stronger than the increase in the heat rejected in the radiator.
The methodology proposed is simple, can be applied to vehicles of different engines types and power, when the power demand curve is close to one of the tractive power curves.
Further studies are currently conducted for cases where the power demand curve is between the tractive power curve of different gears.