Thermodynamic analysis of gasoline-fueled electronic fuel injection digital three-spark ignition (EFI-DTSI) engine

Numerous researchers have devised various strategies to improve the combustion efficiency of the internal combustion engine. Despite continuous improvement during past decades, there is still scope for further development in engine performance. This paper analyzes the energy and exergy distribution of a single-cylinder 199.5 cc electronic fuel injected three-spark ignited high-speed petrol engine. The engine is operated at 25%, 50%, 75%, and 100% throttle positions for different speeds of 4000–10,000 rpm with an increment of 2000 rpm. From the detailed heat balance analysis, the best results obtained are: maximum brake thermal efficiency of 34.9% corresponding to 6000 rpm at 50% throttle opening, minimum heat carried away by exhaust gas of 18.5% at 4000 rpm and 25% throttle position, minimum heat carried by cooling water as 13% for 10,000 rpm and 25% throttle, and the minimum unaccounted energy loss of 26.6% under the condition 8000 rpm and 75% throttle position. However, the best results of exergy analysis are: second law efficiency of 51.93% corresponding to 4000 rpm and 25% throttle, maximum exergy transfer for useful work as 33.7% concerning 6000 rpm and 50% throttle, minimum exergy transfer for exhaust gas as 15.7% for 6000 rpm and 25% throttle, minimum exergy transfer associated with coolant of 4.6% at 4000 rpm and 25% throttle, and minimum exergy destruction of 39.4% corresponding to 8000 rpm and 50% throttle, respectively.