进气加入CO2对直喷式柴油机燃烧的影响

在直喷式柴油机上研究了进气加入CO2气体对其燃烧特性以及发动机性能和排放品质的影响.研究结果表明,进气加入CO2,柴油机的混合气形成过程几乎不受CO2气体加入量的影响,主要反映在着火延迟期随着CO2加入量的增加而变长,燃烧持续期缩短,燃烧最高温度降低.同时导致柴油机的最大爆发压力和压力升高率降低,并且其出现的位置后移,充气效率下降,排气温度上升.加入CO2后,NOx排放有较大下降,HC、CO稍有增加,烟度受到的影响不大.

EFFECT OF CO2 ADDED IN INTAKE AIR ON COMBUSTION PROCESS IN DI DIESEL ENGINE

The paper reports the investigations in the effect of CO2 added in intake air on combustion process in direct injection diesel engine. The tests were carried out on a single cylinder optical engine and 4-cylinder product diesel engine respectively. The experimental results in the optical engine showed that the mixing process of engine remained unchanged when CO2 was added in the intake air. However, the ignition delay would be extended and the periods of visible flame be shortened, and the flame spread rate reduced as well as the highest combustion temperature in cylinder decreased as CO2 added in intake air. The testing results on the 4-cylinder engine revealed that the maximum pressure and the rate of pressure rise in cylinder would be lowered and the occurring time of highest pressure would be deferred, meanwhile the volumetric efficiency of intake air be decreased and the exhaust temperature gone up while CO2 added in intake air. The investigation also illustrated that the engine exhaust emissions changed much, NOx lower, HC and CO higher, soot remained the same.