The Study Of Hcci Characteristics And Engine Performance With Low-ron Gasoline Surrogate Fuels

With the development of the world economy, the automobile emission pollution has become an important source of urban pollution. On this basis, the vehicle engine is the main battle field of energy saving and emission reduction. Perfecting the combustion process of engine, improving the energy utilization can yet be regarded as an effective way to solve environmental problems.HCCI combustion, with the method of homogeneous mixture compression ignition, is a kind of high combustion efficiency, low emission pollution way for engines. Nowadays the HCCI concept has become a hot research topic in this field. The low-RON surrogates,with a better dispersbility and low aromatic hydrocarbon pollution, is a new kind of efficient, clean, and environmental protection fuels. In this article, the low-RON surrogates would be combined with the HCCI technology, and the preliminary study will be conducted with the low-RON surrogates in an HCCI simulation.The combustion of HCCI was mainly controlled by the chemical kinetics. Studying the chemical kinetics of fuels was meaningful for the combustion charge. At present, the primary reference fuel(PRF), which contained of iso-octane and n-heptane, was a kind of substitution of gasoline. On this basis, putting toluene into PRF would be formed as a new surrogate as toluene reference fuel(TRF). In this article, a simplified TRF kinetic(142species and 468 reactions) was proposed based on a kind of typical TRF kinetic by researchers abroad, which was added by other simplified PRF kinetics. The ignition delay time modified prediction of the new kinetic in a shock tube and the HCCI engine seemed as a closer result compared with the experimental data, which was proved the veracity of the new kinetic.Using the new TRF kinetic into the simulation of a HCCI engine model with the low-RON surrogates was an efficiency way to analyze the influence of different engine working condition. The change of heat production, pressure, and temperature of the engine would be clearly expressed using different initial conditions. The results showed that the higher inlet pressure, higher inlet temperature, larger compression ratio, and the leaner mixture could lead improved combustion efficiency in an HCCI engine. But the engine structure and the strength would be limited. Using multi-zone model shows a close to theactual engine. In this article the nine-zone model was used to simulate the combustion and emission performance, which was closer to the actual HCCI engine.To analyze the performance of an HCCI engine which used the low-RON surrogates, a whole HCCI engine model was built in one-dimensional whole engine software. The model was based on a GDI gasoline engine. The TRF surrogates kinetics was put into the combustion module in the software. An intact characteristic could be concluded. Compared with the origin GDI gasoline engine, the low-RON HCCI engine showed a much better economy, emission and power performance. However the HCCI engine which used the low-RON surrogates could be only used in the low-load or moderate-load situation, so that the operation condition was limited.