Impact of the Fast Engine Cooling of a Gasoline Engine on Exhaust Emissions and Fuel Consumption 2008-01-2441

European regulations requires a minimum duration of 6 hours between two approval tests; however, as this duration is not sufficient for a complete engine cooling, most car manufactures use a duration of 24 hours. This higher duration implies larger cooling rooms and thus increased cost. In this work, different modes of fast cooling based on ventilators were tested in the case of a passenger car equipped with a gasoline engine. The best mode, for development but also for industrial purposes, is the one with the ventilator at the front of the vehicle with open hood and two smaller ventilators blowing in the engine. Using this cooling mode, the engine respects European regulations. A comparison between this mode of fast cooling and a mode of natural cooling of 24 hours shows that the two modes have very similar fuel consumption (expressed as CO₂ emissions) and engine-out emissions of regulated pollutants (CO, HC and NOx). The tail-pipe emissions of the fast engine cooling are lower than the natural cooling at 24 hours; however these differences are within the repeatability limits. The results of this study shows that a fast cooling mode can be used for engine tuning and industrial purposes with a significant gain of time and cost.