正丁醇-汽油HCCI发动机燃烧特性

Combustion Characteristics of a HCCI Engine Fuelled with n-Butanol-Gasoline Blends

在一台单缸4冲程发动机上利用负气门重叠角方法,研究了燃用不同掺混比的正丁醇-汽油混合燃料时,均质充量压缩着火(HCCI)发动机的燃烧特性.结果表明,排气门关闭时刻对缸内残余废气率和平均指示压力(IMEP)影响较大.进气门开启时刻通过有效压缩比影响缸内温度和着火时刻,进气门开启时刻对着火时刻的影响与转速有关.在相同条件下,随着正丁醇掺混比的增加,正丁醇-汽油HCCI发动机的着火时刻提前,燃烧持续期缩短,但IMEP下降.而且HCCI发动机使用正丁醇-汽油混合燃料时比使用汽油时更容易发生爆震.

Combustion characteristics of a homogeneous charge compression ignition （HCCI） engine fu- elled with n-butanol-gasoline blends were investigated on a single cylinder four stroke engine using the negative valve overlap. Results show that exhaust valve closing timing evidently affects the residual gases in the cylinder and indicated mean effective pressure （IMEP）. Intake valve opening （IVO）timing affects the in-cylinder temperature and ignition timing through changing the effective compression ratio. The ef- fect of IVO timing on ignition delay is dependent on engine speed. Furthermore, with the increase of n- butanol volume fraction in the blends, ignition is advanced, combustion duration is shortened and IMEP is decreased under the same operating condition. In addition, the n-butanol-gasoline HCCI engine is prone to knock compared to the gasoline counterpart.