Throttling effect on the availability and sustainability of a gasoline-fuelled spark ignited multi-cylinder engine

Large energy waste is one of the internal combustion engine challenges, making it unsustainable and unfriendly to the environment. Charging the spark ignition engine with the required fuel-air mixture is associated with a particular quantity of energy loss due to flow throttling. Throttle position effect on the availability, sustainability, and environmental trends of a gasoline, spark-ignited engine was evaluated based on thermodynamic analyses of real experiments. The availability and sustainability analyses were performed utilizing the relations governing the thermodynamic system under various engine speeds (1500–4000 rpm) at part and wide-open throttle ( POT and WOT ) conditions. The results indicated that the WOT position mostly ensures the best sharing of useful availability, i.e., 2% greater, more sustainable, i.e., 3% better, and environmentally friendly, i.e., 16% healthier, engine operation for the entire tested speed range. On the other hand, an optimum engine speed, mostly 3000 rpm, of the tested engine yielded the maximum efficiencies, i.e., 3% higher, lowest entropy production, i.e., 15% lower, and best availability proportions, as well as the most sustainable and environmentally friendly operation mode. Furthermore, a considerable perspective of the waste heat recovery of the associated availability with exhaust gases was achieved under POT and WOT conditions. The acquired improvement in engine efficiency based on the recovery potential was in the range of 3% to 19.7% and 13.6% to 24% for the WOT and POT conditions, respectively. However, the detected recovery rate and efficiency improvement were randomly tended with engine speed variation. In terms of the recovery potential, the highest engine efficiencies were about 46% and 50% at 3000 rpm, for the POT and WOT conditions, respectively. Finally, in average around 10% and 52% increment with 20% and 24% reduction was detected for the environmental impact of the CO 2 , NO x , CO and HC, respectively, under the WOT condition in comparison with POT condition.