残余废气

内部EGR是利用进排气门配气相位的变化，使发动机气缸内的残余废气量增加，达到降低最高燃烧温度和减小NOX排放的目的。

Internal EGR is the use of intake and exhaust valves with gas phase changes so that the residual gas inside the engine cylinder increased , lowering the maximum combustion temperature and reducing NO_X emissions purposes .

研究发现残余废气中含有较多种类的醛、酮类化合物，但大部分醛、酮类化合物的浓度都低于1ppm，只有甲醛和乙醛的浓度较高。

The analysis results indicated that there were many kinds of carbonyl compounds in residual gas but only the concentrations of formaldehyde and acetaldehyde were high while the concentrations of other carbonyl compounds were lower than 1 ppm .

而调整后再燃用汽油时就可能引起爆震或残余废气过高。因此应尽可能缩短汽油/CNG两用燃料汽车的过渡时间，加快CNG加气站的建设，将两用燃料汽车改为纯CNG汽车。

It may cause cylinder-knocking and more residual exhausting gas if gasoline is used again after adjustment , so bi-fuel vehicle is modified into mono-fuel CNG vehicle to shorten period of gasoline / CNG bi-fuel vehicle and step up construction of CNG gas station .

其中结构参数包括楔形燃烧室角度、活塞顶形状和火花塞位置，运行参数包括点火时刻、混合气浓度和残余废气量。

The structure parameters include wedge-shaped combustion chamber angle , piston top shape and the locations of dual-spark .

设计了几种具有小持续角的特殊进、排气凸轮轴，以满足高内部残余废气率。

Two kinds of camshafts with short duration angle and small lift cam profile were designed to meet the high residual gas rate .

阐述了为捕捉残余废气而改变气门正时过程中存在的泵气损失和回流损失问题。

The problems ( such as pumping loses and backflow loses ) which are caused by changing valve timing in order to trapping residuals are illustrated .

结果表明，对汽油机有效功率影响显著的参数为残余废气量和混合气浓度，其次是楔形燃烧室角度。

The results showed that the most significant parameters impact active power were mixture concentration and residual concentration , followed by the wedge-shaped combustion chamber angle .

由于缸内残余废气较多且燃烧温度较低，因而发动机在低负荷时的燃烧与排放性能通常较差。

Because of the high residual gas fraction and low combustion temperature , SI engines always gain the dropped combustion and emissions performance at low speed and load conditions .

排气门关闭越早，缸内的残余废气量增加，每循环进气量减少，燃烧持续期变长，PIMEP减小，然而泵气损失减小；

Early exhaust valve closing ( EVC ) timings result in high residual fractions in the cylinder , decreasing air mass in cylinder per cycle , increasing combustion duration , and decreasing IMEP while the pumping loss is decreased .

该系统通过在负气门重叠期进行燃油喷射并利用残余高温废气热氛围促进燃油蒸发实现均质混合气的制备，通过外部冷却EGR实现燃烧相位和速率的控制。

In this system , fuel is injected in negative valve overlap ( NVO ) and the high-temperature residual gas benefits the fuel vaporization .