对汽油机掺烧代用燃料，其动力性会受到影响的问题进行了理论分析，说明影响动力性能的几个参数，得到了一个可以反应混合燃料混合气热值变化情况的参数．在进行了汽油机少量掺氢燃烧的试验得出的结果表明，在低速时有功率损失，随着发动机转速的提高，功率损失减少，额定工况功率有所提高，与理论分析结果比较吻合。 A theoretical analysis is made on the problem that the kinetic energy will be affected when the alternative fuel is blended into the gasoline engine. Several parameters that affect the dynamic performance are explained and a parameter that can reflect the change of the calorific value of the mixed fuel gas mixture is obtained. The results of experiments with a small amount of hydrogen-fueled gasoline engine showed that there was power loss at low speed, power loss decreased and power at rated condition increased with the increase of engine speed, which was in good agreement with the theoretical analysis.