Experimental Study of Performance of Spark Ignition Engine with Gasoline and Natural Gas

The tests were carried out with the spark timing adjusted to the maximum brake torquetiming in various equivalence ratios and engine speeds for gasoline and natural gas operations. In thiswork, the lower heating value of gasoline is about 13.6% higher than that of natural gas. Based on theexperimental results, the natural gas operation causes an increase of about 6.2% brake special fuelconsumption, 22% water temperature difference between outlet and inlet engine, 3% exhaust valve seattemperature, 2.3% brake thermal efficiency and a decrease of around 20.1% maximum brake torque,6.8% exhaust gas temperature and 19% lubricating oil temperature when compared to gasolineoperation. The results also revealed that, over the entire range of engine speed and equivalence ratio, theexhaust gas temperature and the lubricating oil temperature for gasoline operation is higher than that ofnatural gas operation while the exhaust valve seat temperature for natural gas operation is higher.