采用双球挤流燃烧室的汽油机缸内燃烧特性的测试

Tests of In-cylinder Combustion Characteristics of Gasoline Engine with Dual-ball Squish Combustion Chamber

在150FMI汽油机挤流环面半球形燃烧室结构基础上,开发了双球挤流燃烧室。燃烧测试表明:双球挤流燃烧室能获得更高的平均有效压力,抑制爆燃效果明显;但燃烧放热率较低,循环变动有所增加。将双球挤流燃烧室与半球形燃烧室、挤流环面半球形燃烧室、蝶形挤流燃烧室的燃烧放热规律进行综合比较,发现双球挤流和蝶形挤流燃烧室的着火落后期明显长于半球形和挤流环面半球形燃烧室,带挤流环面半球形燃烧室的速燃期明显短于双球挤流和蝶形挤流燃烧室;强烈压缩挤流有延缓缸内燃烧过程的趋势。适当增大点火提前角,可使双球挤流燃烧室速燃期放热明显加快,平均有效压力提高,循环变动率降低,并保持抑制爆燃的良好特性。

Dual-ball squish combustion chamber is developed based on the semi-spherical combustion chamber with squish ring for 150FMI gasoline engine.Combustion tests show that dual-ball squish combustion chamber can get higher mean effective pressure and suppress knock more effectively but with lower heat release rate in combustion and more apparent cyclic variation.The comparison between heat release rules of four types of combustion chambers reveals that the ignition lags for dual-ball squish chamber and butterfly squish chamber are longer than that for semi-spherical chamber and semi-spherical chamber with squish ring,and the rapid-burning period of semi-spherical chamber with squish ring is obviously shorter than that for dual-ball and butterfly squish chambers.It is considered that intense squishing has a tendency to retard in-cylinder combustion.However,properly increasing spark advance angle can raise the heat release rate,increase the mean effective pressure,reduce the cyclic variation and maintain the good feature of detonation suppression of dual-ball squish combustion chamber.