液化石油气与汽油燃烧特性的对比试验研究

在点燃式发动机上分别燃用液化石油气和汽油,通过采集示功图并进行放热规律计算,对两种燃料在相似工况、相同过量空气系数下的燃烧特性进行对比分析。结果表明,在不改变样机结构和点火提前角的情况下,燃用液化石油气造成样机最大输出功率下降了7.64%。标定工况下,过量空气系数的变化对样机燃用汽油时的功率影响较大。两种燃料标定工况下的比热耗均随过量空气系数的增大而降低,但液化石油气降低的幅度较小。相似工况、相同过量空气系数下,相对于汽油,液化石油气的滞燃期短,燃烧持续期短,燃烧速度快。

Comparative Researches on Combustion Characteristics of Liquefied Petroleum Gas and Gasoline

Experiments were separately carried out on liquefied petroleum gas （LPG） and gasoline as fuel for a spark ignition （SI） engine. According to the indicator diagram and the calculation of corresponding heat re- lease, combustion characteristics of the two fuels were analyzed. The results showed that using LPG would lead to 7.64% power reduction when the structures and ignition advance angle of the engine were remained. At ra- ted speed and full load, the change of excess air ratio has a greater effect on the engine fueled with gasoline than that fueled with LPG; the specific heat consumption of both fuels decreases with the increase of load. Be- sides, under the same excess air ratio, LPG has a shorter combustion delay period, faster combustion speed and shorter combustion period than gasoline.