【摘要】 针对某电控高压共轨重型柴油机,研究了二级增压及EGR系统对燃烧、排放及动力性能的影响规律。研究结果表明,相同EGR率下,二级增压柴油机CO,HC和炭烟排放均低于单级增压,且随EGR率增大,缸内燃烧压力、放热率峰值及缸内平均温度均有所降低,滞燃期变化不大。相比单级增压,二级增压能够实现更大的EGR率,在更宽的EGR率范围内保持发动机良好的动力性和经济性;随EGR率增大,EGR对二级增压柴油机NOx排放的抑制效果更为明显,且能够在更宽的EGR率范围内维持较低的炭烟排放;NOx与燃油消耗率和烟度的平衡关系也明显优于单级增压。更多还原

【Abstract】 The effect of EGR and two-stage turbocharging on combustion,emission and power performance was investigated on a electronic control high-pressure common rail heavy duty engine.The result shows that the CO,HC and soot emissions of two-stage turbocharged diesel engine are lower than the original under the same EGR rate.With the increase of EGR rate,the maximum in-cylinder pressure,the peak heat release rate and the in-cylinder average combustion temperature decrease and the ignition delay period almost keeps unchanged.Compared with the original engine,two-stage turbocharged engine can achieve the higher EGR rate and can keep good power and economy performance in a wider range of EGR rate.With the increase of EGR rate,the inhibition NOxemissions become more obvious and the lower soot emissions can be maintained in a wide range of EGR rate.The compromise between NOxemission and fuel consumption rate as well as soot emission is also significantly better than the single-stage turbocharged engine.更多还原