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Clean High-speed Combustion with Two-phase Stratification into Rich and Lean Mixtures

通过两相分层形成浓混合气和稀混合气的清洁高速燃烧

基本信息

批准号：
09650216
负责人：
OGAWA Hideyuki
金额：
$ 2.11万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650216/
关键词：
Internal combustion engine Stratified charge engine Stratified charge combustion Lean burn Nitric oxide Exhaust gas emission Lean limit Thermal efficiency

项目摘要

A direct injection stratified charge engine with two-stage fuel injection determined by the piston phase was proposed, and combustion and exhaust gas emissions are discussed in this research. The formation of two-phase stratification of rich and lean mixtures was realized with the two-stage fuel injection into a double cavity in the piston top at suitable timings : the first-stage injected into an outer cavity for the lean mixture and the second-stage into an inner cavity for the rich mixture. An premium gasoline for automobiles was used as the tested fuel. A multi-dimensional CED engine simulation code "FIRE" was used to analyze the mixture formation process in the combustion chamber before the experiments in the engine. The simulation showed that the rich mixture was formed in a part of the inner cavity while the mixture almost in the entire combustion chamber is heterogeneous and leaner than the mixture strength expected from the injected amounts. The simulation predicted that the mixture was very lean near the spark plug at the cylinder head, and the position of the plug gap was changed to near the bottom of the cavity with extended electrodes in the experiment and the stability of combustion was significantly improved. The injection timing in the inner cavity should be during the compression stroke rather than the intake stroke to prevent the diffusion of fuel out of the inner cavity. The injection timing in the outer cavity should be during the intake stroke to insure a homogeneous mixture in the entire combustion chamber.

提出了一种基于活塞相位控制的两级燃油喷射的缸内直喷式分层进气发动机，并对其燃烧和排放进行了研究。通过在合适的时刻将燃料分两级喷射到活塞顶部的双腔中，第一级喷射到贫混合气的外腔中，第二级喷射到富混合气的内腔中，实现了富混合气和贫混合气两相分层的形成。以一种优质车用汽油为试验燃料。在发动机试验前，利用多维CED发动机模拟软件FIRE对燃烧室内混合气形成过程进行了模拟分析。模拟结果表明，富混合气形成的内腔的一部分，而几乎在整个燃烧室的混合气是不均匀的，比从喷射量预期的混合气强度稀薄。模拟结果表明，气缸盖火花塞附近的混合气非常稀薄，实验中将火花塞间隙位置改为靠近腔底，并采用延长电极，燃烧稳定性得到明显改善。内腔中的喷射正时应在压缩冲程而不是进气冲程期间，以防止燃料扩散出内腔。外腔中的喷射定时应在进气冲程期间，以确保整个燃烧室中的均匀混合物。