电喷汽油机过渡工况排放的测量与分析

测量了某车用电喷汽油机在冷起动、冷加/减速、空载热突减速及热加速等工况下排气中CO,HC,NOx,CO2和O2的体积分数,并分析了原因。结果表明,发动机冷起动时排出大量的HC和CO,而此时催化转化器尚未起燃,需从混合气制备和燃烧过程优化等方面对该阶段着重控制;冷加/减速工况下,CO,HC和NOx排放均出现了峰值,实际运行时应尽量减少此类操作;空载热突减速工况下,HC排放出现了较大的峰值,表明减速断油策略仍需进一步研究;而热加速工况的控制重点则是NOx排放。

Measurement and Analysis on Emission from EFI Gasoline Engine under Transient Conditions

The volumetric proportions of CO,HC, NOx,CO2 and O2 from the exhaust of EFI gasoline engine were measured and analyzed under the working conditions of cold-start,cold acceleration/deceleration,no-load warm sudden deceleration and warm acceleration.The results show that a great deal of HC and CO is emitted during its cold-start phase of the engine.However,the catalytic converter doesn't begin to work yet in this phase.So the control of exhaust emission depends mainly on the preparation of composite gas and the optimization of the combustion process.During its cold acceleration/deceleration,there are peak values in the curves of CO,HC and NOx emissions,showing that it is necessary to avoid these operations as much as possible in the actual running.During its no-load warm sudden deceleration,there is a large peak value in the curve of HC emission,showing that the strategy of cutting off oil need be researched further.During its warm acceleration,the key of exhaust control is controlling NOx emission.