Effect of injection strategies on preignition tendency in a turbocharged single cylinder engine

Preignition is an abnormal combustion that has recently emerged as a bottleneck to downsizing, and efficiency improvement in spark ignited engines. Fuel-oil interaction on the cylinder liner is thought to be a major cause of the phenomenon. In this context, the current work uses varying injection strategies, leading to varying levels of homogeneity and fuel impingement on the cylinder liner, to (understand) establish potential causes of the preignition phenomenon. The injection is varied from one extreme of fuel-liner interaction to another; going from central direct injection to port injection of gaseous fuel and various combinations thereof. It was observed that preignition tendency is heavily dependent on the amount of fuel hitting the cylinder liner. As the phenomenon is stochastic, the frequency of its occurrence can be correlated with the fuel-liner interaction, provided all other test variables are held constant. The results motivated us to test the engine for maximum preignition-limited indicated mean effective pressure (IMEP) using dual fuel mode of gasoline and methane.