How to Put the HCCI Engine to Practical Use: Control the Ignition Timing by Compression Ratio and Increase the Power Output by Supercharge

In this study, compression ratio for controlling ignition and combustion for HCCI engine is proposed. Compression ratio can be changed higher for leaner mixture or lower for richer mixture to prevent misfire and rapid combustion respectively. In order to increase the power rate of the HCCI engine to a practical use level, supercharge can be combined with various compression ratio. To ascertain the efficacy on ignition and combustion, a series of bench tests and combustion simulations with constant pressure were conducted. The testing result shows that compression ratio is very useful for HCCI control: the engine can run over a wider load range of equivalent ratio without misfire or rapid combustion, and the power rate is comparable to a DI (Direct Injection) engine when a supercharger is installed. The findings from the combustion simulation are: progress (or degeneration) of low temperature oxidation is highly dependent on pressure but pressure does not affect the reaction rate of high temperature oxidation.