用扩散及准均质混合气压燃的组合燃烧降低柴油机碳烟与NOx排放的研究

在柴油机的一部分工况采用现有的扩散燃烧方式，另一部分工况采用柴油引燃醇燃料均质混合气的组合燃烧方式，利用醇燃料的高汽化潜热和含氧的特性，达到同时降低柴油机碳烟及氮氧化物(NOχ)的目的，并且避免在小负荷燃烧醇燃料带来的高醛类排放问题。在一台4缸水冷直喷式发动机上采用上述组合燃烧法进行试验，从发动机进气管处喷进乙醇形成均质混合气，然后由柴油引燃。由电控装置控制乙醇喷入量及其喷入时刻。试验结果表明，与原机相比，碳烟和NOχ排放分别减少了50％和30％，同时燃料的消耗率也有大幅度降低。

Study on Reduction of PM and NOx by Compound Combustion of Diffusion Combined with Quasi-HCCI

A new compound combustion method is proposed, which is composed of two modes of the combustion occurring in diesel engine, one mode adopts conventional diffusion combustion using diesel fuel at low load and starting as well as warm up periods, and the other utilizes Quasi-HCCI (homogenous charge compression ignition) formed by ethanol mixture combined with diesel fuel at other operating conditions. The method is used for diesel engines to simultaneously reduce soot (PM) , nitride oxidation (NO_x) emissions, and acetaldehyde emissions. The experiments were conducted on a DI 4-cylinder diesel engine. Ethanol mixture was formed through an injector with low pressure fixed at intake manifold, and the amount and time of ethanol injected controlled by an electronic unit. The experimental results showed that soot and NO_x emissions of the engine decreased by 50% and 30% respectively, and the engine fuel economy also improved compared with the conventional combustion.