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在一台改进的单缸发动机上实现了乙醇火花点火燃烧和均质压燃两种燃烧方式。通过进气预热的方法得到了乙醇HCCI燃烧方式的工作区,并定义了燃烧的爆震边界和失火边界。研究结果表明,在采用进气预热的方式下,仅靠空气稀释,乙醇燃料的HCCI燃烧工作上限最大达到了SI工作方式下的50%。在乙醇HCCI燃烧的工作区域内,与SI燃烧方式相比,混合气很稀,因此缸内温度低,NOx的排放降低幅度最大可达58%以上。随着负荷的越小,混合气变得更稀,缸内燃烧温度进一步降低,NOx的降低幅度越大。但在整个负荷变化范围内CO和HC的排放都比较高。
In an improved single-cylinder engine to achieve ethanol spark ignition and homogeneous combustion two combustion methods. The work area of the ethanol HCCI combustion mode is obtained by the method of preheating the intake air, and the detonation boundary and the fire boundary of the combustion are defined. The results show that under the mode of intake preheating, the upper limit of HCCI combustion of ethanol fuel can reach 50% under SI mode only by air dilution. Compared with the SI combustion mode, the mixed gas is very lean in the HCCI combustion working area, so the in-cylinder temperature is low, and the emission of NOx can be reduced by more than 58%. As the load becomes smaller, the mixture becomes leaner, the combustion temperature in the cylinder is further reduced, and the reduction of NOx is larger. However, emissions of CO and HC are high over the entire load range.