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Studies on Improvement of Combustion with an Accumulator-type Fuel Infection System Coupled with Pilot Injection

蓄能器式燃油喷射系统与引燃喷射改善燃烧的研究

基本信息

批准号：
01550178
负责人：
WAKURI Yutaro
金额：
$ 1.34万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01550178/
关键词：
Compression Ignition Engine High pressure fuel injection Pilot injection Particulate Pre-mixed Combustion Diffusion Combustion Fuel spray Combustion Noise

项目摘要

Studies have been carried out to examine both the effects of high pressure fuel injection and pilot injection on the improvement of Combustion, that means reductions of BSFC and exhaust smoke density without increase in NO emission, in a Diesel Engine. The effects were clarified not only by operation tests with the test engine equipped with a newly developed accumulator-type fuel injection system, but also from analyses of high sped photographs of fuel spray and flames taken in another test engine with a visualized combustion chamber. As the results of experiment following Conclusions have been obtained.(1) It is effective on the improvement of combustion characteristics to use the injection nozzle with smaller hole diameter corresponding to the high injection pressure, because of the increase in the excess air ratio of fuel spray.(2) The pilot/pre injection followed by high pressure injection is effective on reductions of BSFC and exhaust smoke density without increase of NO emission.(3) Residual fuel spray is more difficult to be dispersed by air swirl and needs high swirl intensity for the optimum combustion than marine diesel oil.(4) Combustion of impingement of fuel spray on the piston wall and air swirl is an effective means to improve the combustion of residual fuel spray in the diffusion combustion period by talking off the gaseous part and small droplets from the liquid core and supplying the spray with fresh oil.(5) Increase of combustion air temperature in the combustion chamber improves the combustion of residual fuel spray by accelerating the evaporation of distillate components.(6) Attention should be paid to the fact that the heat release rate of residual fuels goes down extremely with the increase of ignition delay at low compression air temperature.

研究了高压燃油喷射和预喷射对改善柴油机燃烧性能的影响，即在不增加NO排放的情况下降低燃烧室容积和烟度。不仅通过配备新开发的蓄压器型燃油喷射系统的试验发动机的操作试验，而且还通过分析在另一台具有可视化燃烧室的试验发动机中拍摄的燃油喷雾和火焰的高速照片来阐明这些效果。根据实验结果，得出了以下结论。(1)采用与高喷射压力相对应的小孔直径的喷嘴，可以有效地改善燃烧特性，这是因为燃油喷雾的过量空气系数增大。(2)预喷射和高压喷射相结合的喷射方式能有效降低燃烧室容积率和烟度，且不增加NO排放。(3)与船用柴油相比，残余油雾更难被空气旋流分散，需要更高的旋流强度才能达到最佳燃烧。(4)燃油喷雾撞击活塞壁面和空气旋流燃烧是改善扩散燃烧期残余燃油喷雾燃烧的有效手段，它可以将气态部分和小液滴从液核中分离出来，并向喷雾中补充新鲜油。(5)燃烧室中燃烧空气温度的升高通过加速馏出物组分的蒸发来改善残余燃料喷雾的燃烧。(6)应注意的是，在低压缩空气温度下，随着着火延迟期的增加，残余燃料的放热率急剧下降。