Development And Application Of Transient Combustion Analysis System For HCCI Engine

HCCI (Homogeneous Charge Compression Ignition) combustion controlled by complex chemical kinetics is influenced by many sensitive factors. So not only steady conditions but also transient operation conditions are important to learn the characteristics of HCCI. A real-time multi-function system to do measurement, control and analysis in combustion processes is crucial in HCCI engine experiment.With AC6111 high-speed data acquisition card, a transient combustion analysis system has been established. The object-oriented method and a number of program tools such as C++ Builder 6.0 and SQL Sever 7.0 were applied to develop a software system. It could sample multi-parameter at the same time, realize real-time combustion monitoring and analysis, including ignition timing, maximum pressure, COV (Coefficient of Variation) of IMEP. This system provides valuable information to further HCCI combustion control, effectively improves experiment precision and reduces the expense.The competitive experiment between gasoline oil and PRF, Preference Research Fuel was carried out to do research in ignition timing, combustion duration, COV of IMEP and so on with the aid of the new real-time data acquisition and analysis system. The results show that, competed with PRF at same RON, the component of gasoline oil has strong influence on combustion, which results in advanced ignition timing, shorted combustion duration, but lower thermal efficiency at the beginning. There would be other parameters to evaluate the ignition capability, not only RON. As for the influence of inlet mixture temperature, it connected with density of mixture and characteristics of fuel. With the increase of density, the influence of temperature on combustion parameters become weaker; with the decrease of temperature the density has smaller effect on combustion parameters.