不同工况下EGR率对发动机性能的影响

韩立伟，史明杰，徐金辉，旷云龙

比亚迪汽车工业有限公司，广东 深圳  130022

摘要：为研究不同工况下EGR率对发动机性能的影响，调整EGR阀开度、节气门开度和点火角，对某1.5 L自然吸气发动机进行台架试验，分析不同EGR率下发动机的泵气损失、爆震趋势、燃烧持续期。试验结果表明：在低负荷时，随着EGR率增加，泵气损失降低，燃烧持续期增加，EGR率为10%时，泵气损失和燃烧持续期达到平衡，比油耗最低；在中负荷时，随着EGR率增加，节气门接近全开时，泵气损失最低，比油耗最低；在外特性时，EGR率小幅度增加（由0增加到4%），抑制爆震趋势明显，燃烧中心显著提前，比油耗显著降低。该研究可为发动机性能优化和EGR的标定提供参考。

关键词：EGR率；比油耗；泵气损失；燃烧持续期

Influence of EGR rate on engine performance under different operating conditions

HAN Liwei, SHI Mingjie, XU Jinhui, KUANG Yunlong

BYD Auto Industry Company Limited, Shenzhen 130022, China

Abstract：In order to study the effect of EGR rate on engine performance under different operating conditions, a 1.5 L naturally aspirated engine is tested on the bench to analyze the pumping loss, knock trend and combustion duration of the engine under different EGR rates by adjusting the EGR valve opening, throttle valve opening and ignition angle. The test results show that at low load, with the increasing of EGR rate, the pumping loss decreases and the combustion duration increases. When the EGR rate is 10%, the pumping loss and the combustion duration reach a balance, and the fuel consumption is the lowest. At medium load, with the increase of EGR rate, when the throttle valve is close to full opening, the pumping loss is the lowest, and the fuel consumption rate is the lowest at this time. At full load, the EGR rate is slightly increased (4%), which can result that the knocking suppression trend is obvious, the combustion center is significantly advanced, and the fuel consumption rate is significantly reduced. The study can provide a reference for engine performance optimization and provide guidance for EGR calibration.

Keywords:EGR rate; fuel consumption rate; pumping loss; combustion duration