单气缸自由活塞膨胀机-直线发电机试验研究

Experimental Investigation of a Novel Single Cylinder Free Piston Expander-linear Generator

为了提高内燃机能量利用率,自主研发了1台可用于有机朗肯循环余热回收系统的单气缸自由活塞膨胀机-直线发电机(FPE-LG)。在压缩空气试验平台上实现了FPE-LG的连续稳定运行,验证了单气缸FPE-LG工作原理的可行性。在大量试验基础上,分析了驱动压力、外接负载电阻对单气缸FPE-LG输出特性的影响机制。研究结果表明:FPE-LG输出功率呈现较为规律的正弦波动,对于该试验样机而言,当驱动压力为0. 6 MPa、外接负载电阻为50Ω时,峰值输出功率可达到58. 7 W;提高驱动压力可以明显提高均方根电压和峰值电流,但驱动压力的提高对FPE-LG自由活塞膨胀机膨胀功-直线发电机输出电能转换(简称功-电转换)效率影响很小;当外接负载电阻小于60Ω时,随着外接负载电阻的增大,FPE-LG的功-电转换效率从13. 4%上升到24. 7%;对于该FPE-LG而言,当外接负载电阻为60Ω时,单气缸FPE-LG的实际膨胀功最大,功-电转换效率最佳。

A single cylinder free piston expander-linear generator （FPE-LG） used for organic Rankine cycle （ORC） waste heat recovery system is developed to improve the energy efficiency of the internal combustion engines. FPE-LG can operate continuously and stably under the condition of high driven pressure, which indicates that the working principle of single cylinder FPE-LG is feasible. The eftects of driven pressure and external load resistance on the output characteristics of single cylinder FPE-LG are investigated through experiment. The experimental test results show that the power output of FPE-LG exhibits a regular sinusoidal fluctuation, and the peak power output can reach 58.7 W when the driven pressure is 0.6 MPa and the external load resistance is 50 Ω. The increase in driven pressure can in- crease the RMS voltage and peak cmTent significantly. However, it has little effect on the power-electric conversion efficiency of FPE-LG. When the external load resistance is less than 60 Ω, the power-electric conversion efficiency ＊/of FPE-LG increases from 13.4% to 24.7% with the increase in external load resistance. When the external load resistance is 60 Ω, actual expansion work （AEW） , 1FAEW, of the single cylinder FPE-LG is the largest and the power-electric conversion efficiency is the best. The continuous in- crease in the external load resistance value has little effect on 1FAEw and η.