自由活塞汽油直线发电机起动过程研究

Study on Starting Characteristics of Free-Piston Gasoline Engine for Linear Alternator

为获得自由活塞汽油直线发电机起动过程主要工作特点,对自由活塞汽油直线发电机主要起动方式进行了研究。耦合动力学及热力学方程,建立了起动过程数学模型,理论分析了起动过程中能量的传递与转换关系,并结合试验样机对两种典型起动方式进行了试验研究。研究发现:采用恒定加速度起动模式和恒定推力起动模式均可实现自由活塞汽油直线发电机的起动燃烧,其中采用恒定加速模式有利于第一次压缩气缸实现起动燃烧,然而采用恒定推力起动模式更有利于对侧发动机气缸完成起动燃烧;起动过程中摩擦损失所消耗的能量较少,漏气损失所占的比例较大,在起动设计时不应被忽视。

In order to obtain starting process characteristics of a spark ignited free-piston linear alternator,a starting process simulation model based on coupling the alternator dynamics and thermodynamics equa- tions was established to analyze theoretically energy transference and conversion relationship in starting process. By using the model and actual test way, two typical starting methods were investigated. Results indicate that both start modes of constant acceleration and constant thrust can realize the alternator starting burning; the former is beneficial to the first time compression starting combustion, and the latter beneficial to the opposite cylinder starting combustion. It is revealed that in starting process, gas leakage loss is more than friction loss fraction, that should not be ignored in design.