Effect of fuel-air mixture dilution on knock intensity

Abstract

Effect of fuel-air mixture diluted by inert gas on knock intensity was investigated by using a rapid compression and expansion machine. Dilution of fuel-air mixture decreased knock intensity. As the dilution ratio became high, increase in input heating value did not affect knock intensity too much although it shortened auto-ignition delay. Knock intensity is assumed to correlate with the pressure rising rate when the auto-ignition occurs. Knock intensity was shown as a function of the maximum pressure and the maximum temperature which affect the high temperature oxidation reaction rate.