Potential of exhaust heat recovery for intake charge heating in a diesel engine transient operation at cold conditions

In this paper, an experimental facility is implemented with the aim of improving the performance of internal combustion engines working at low ambient temperatures. Pollutant emissions and fuel consumption are one of the major issues that automotive engineers have to face. Cold engine start and warming up analysis have become important topics for researches. In this work, an exhaust heat recovery system for a diesel engine has been proposed as a solution to cold operation negative effects. The energy obtained from the exhaust gases was used to increase the intake air temperature. The experiments were carried out in transient load conditions at three different levels of ambient temperature (up to −7 °C). Exhaust heat recovery was combined with different strategies of exhaust gas recirculation. Intake air heating results with the heat recovery system show a reduction of 65% in unburned hydrocarbons, 40% in carbon monoxide and 10% in fuel use compared to standard air-air intercooler.