点火定时对增压直喷汽油机燃用甲醇汽油混合燃料微粒排放的影响研究

Investigation on the Effect of Ignition Timing on Particulate Emissions from a Turbo Charged GDI Engine Fueled with Gasoline/Methanol Blends

在一台增压直喷(T-GDI)汽油机上,燃用甲醇体积分数分别为0%、10%、25%、100%的甲醇汽油混合燃料(依次记为M0、M10、M25、M100),进行其微粒排放特性研究,分析了点火定时对微粒排放的影响规律。试验结果表明:燃用M10、M25燃料时,增压直喷汽油机微粒数浓度主要集中在核态区域,微粒质量浓度主要集中在积聚态微粒区域;相同点火定时下,随着甲醇掺混比的增大,微粒数浓度和质量浓度均显著降低,点火定时(以上止点前曲轴转角计)为38°时,M0燃料微粒总数浓度是M100燃料的68倍,总质量浓度为49倍;对于相同燃料,随着点火定时的推迟,微粒数浓度和质量浓度均呈现明显的下降趋势,燃用M25燃料时,点火定时为38°时的微粒总数浓度是18°时的5倍,燃用M0燃料时,点火定时为38°时的微粒总质量浓度是18°时的4倍。

The effect of ignition timing on particulate emissions from a turbo charged gasoline direct injection （T-GDI） engine fueled with gasoline/methanol blends was investigated experimentally. Results show that when the engine is fueled with gasoline-methanol blends of M10 and M25 respectively. The particle number emission is mainly concentrated in the nucleation mode area, but the particulate mass emission is mainly concentrated in the accumulation mode area. For the same ignition timing, the particle number concentration and particulate mass concentration decrease significantly with the increase of mixture ratio. The particle number concantration and particulate mass concentration, with M0 fuel operation are 68 times and 49 times as much as that with M100 fuel operation when the ignition timing is 38° BTDC. For the same fuel operation, the particle number concentration and particulate mass concentration show a significant downward trend with the delay of ignition timing. When using M25 fuel, the total particle number concentration with the ignition timing of 38° BTDC is 5 times that with the ignition timing of 18° BTDC. When using M0 fuel, the total particulate mass concentration with the ignition timing of 38° BTDC is 4 times that with the ignition timing of 18° BTDC.