The operation characteristics of a liquefied petroleum gas (LPG) spark-ignition free piston engine
The operation characteristics of a liquefied petroleum gas (LPG) spark-ignition free piston engine
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DOI：
10.1016/j.fuel.2016.06.060
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发表时间：
2016-11-01
期刊：
影响因子：
7.4
通讯作者：
Kim, Gangchul
中科院分区：
文献类型：
--
作者：
Kim, Jaeheun;Bae, Choongsik;Kim, Gangchul
建立了一台用于发电的双活塞式火花点火自由活塞发动机样机。使用由98%丙烷（和2%丁烷）组成的液化石油气作为燃料。由于发动机的工作范围有限，选择气体燃料与空气进行更好的混合制备。研究了空气流量和交流发电机负荷对自由活塞发动机工作特性的影响。最终的电功率输出由交流发电机负载（或电路内部的电导值）确定。由于感应电流和电压的变化，交流发电机负载改变了活塞动力学。高感应电流恶化的活塞动能，由于高磁阻力施加在活塞上。因此，当增大的交流发电机负载（增大的电流）被劣化的活塞速度（降低的电压）抵消时，就在之前存在最佳电功率输出值。相对于交流发电机负载的发动机功率输出变化也主要是由于活塞动力学的变化。在较低的交流发电机负载条件下，由于较高的活塞动能，活塞功的循环变化较高。工作频率的变化与行程的变化是耦合的。它们随着交流发电机负载的增加而同时降低。在点火时刻的瞬时活塞速度是控制和发动机性能的关键因素。(C)2016爱思唯尔有限公司版权所有
A prototype of dual-piston type spark-ignition free piston engine coupled with a linear alternator was built for electric power generation. Liquefied petroleum gas consisting of 98% propane (and 2% butane) was used as the fuel. A gas fuel was selected for better mixture preparation with air due to limited operation range of the engine. The effects of air flow rate and the alternator load on the operation characteristics of the free piston engine were studied. The final electric power output was determined by the alternator load (or the electric conductance value inside the electric circuit). The piston dynamics was varied by the alternator load due to the changes in the induced current and the voltage. High induced current deteriorated the piston kinetic energy due to high magnetic resistive force applied on the piston. Therefore, an optimum electric power output value existed right before when the increased alternator load (increased current) was cancelled out by the deteriorated piston velocity (decreased voltage). The engine power output change with respect to the alternator load was also mainly due to the changes in the piston dynamics. The cyclic variation of the piston work was higher at lower alternator load condition due to higher piston kinetic energy. The variation of the operation frequency and the stroke were coupled together. They decreased simultaneously with respect to the increase of the alternator load. The instantaneous piston velocity at the spark timing was derived to be a key factor for the control and engine performance. (C) 2016 Elsevier Ltd. All rights reserved.