高压共轨直喷式柴油机混合气浓度场对快速NO生成影响的研究  

Investigate on Effect of Fuel-Air Mixture Equivalence Ratio on Prompt NO Generation in HPCR-DI Diesel Engine

作　　者：林学东[1] 袁方恩[1] 高莹[1] 

机构地区：[1]吉林大学汽车动态模拟国家重点试验室,长春130025

出　　处：《内燃机工程》2012年第3期33-39,44,共8页Chinese Internal Combustion Engine Engineering

基　　金：国家'八六三'高技术研究发展计划--汽车开发先进技术资助项目(2008AA110101)

摘　　要：利用商用CFD软件FIRE,建立轻型车用高压共轨直喷式柴油机燃烧系统的仿真计算模型。在通过试验验证仿真模型和计算方法的基础上,仿真计算分析了燃烧室内混合气浓度场的动态分布特性对快速NO和碳烟生成规律的影响。研究结果表明:直喷式柴油机燃烧过程中快速NO的生成与混合气浓度场的分布特性密切相关,在混合气较稀薄区NO的生成速率对温度的依赖性较强;而在混合气较浓区NO的生成速率对该区温度的依赖性较小,只与浓度场分布特性有关,说明在温度低于1 800K的较浓混合气区域也会生成快速NO。通过虚拟采样计算结果绘制出快速NO生成的Φ-T图,有利于完善直喷式发动机NO的生成机理。A numerical model of combustion system in high pressure common rail direct injection （HPCR-DI） diesel engine for light vehicle was built up by using commercial CFD software FIRE. Validated the model and numerical method by experiment, the effect of transient equivalence ratio distribution of fuelair mixture in combustion chamber on generation of prompt NO and SOOT was investigated. Results show that, the formation of NO in DI diesel engine combustion process is closely dependent on the fuel-air mixture equivalence ratio distribution. The dependence of NO generating rate on temperature is stronger in lean mix- ture zone than in rich mixture zone, and the NO generating rate in rich mixture is related only to the equivalence ratio distribution. It shows that there will generate prompt NO in rich mixture zone below 1 800 K. And the Ф-T figure of prompt NO is calculated from results of virtual sampling. These achievements are of great significance to consummate NO generation mechanism in DI engine.

关 键 词：内燃机 高压共轨直喷式柴油机 混合气形成 浓度场 快速NO 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]