气动发动机的试验研究

为优化气动发动机的设计,提高气动发动机的工作性能,在一台由R175柴油机改装的二冲程气动发动机上进行详细的台架试验研究,并提出两个评价气动发动机性能的新指标--比质量流量和总能量效率.采用变压器机油、冷冻油和特制机油等三种不同的润滑油进行气动发动机的润滑油试验,试验结果表明润滑油对气动发动机的经济性和动力性影响很大.针对水套中无水、注入常温水和开水等三种不同换热条件进行气动发动机的换热试验,试验结果表明加强换热条件对气动发动机的经济性和动力性帮助有限,但多级利用压缩空气可以提高气动发动机的总能量效率.利用三种不同进气提前角的进气凸轮,进行三种不同配气相位的速度特性和负荷特性试验.试验表明:气动发动机在低速阶段拥有较好的经济性和动力性,进气提前角为10 ℃A时,气动发动机性能最好.

EXPERIMENTAL STUDY ON AIR-POWERED ENGINE

To optimize the design of air-powered engine and enhance its performance, an extensive experimental study on engine performance of a two-stroke air-powered engine that is modified from R175 diesel engine is carried out. Two evaluat- ing indicators are newly defined to evaluate the performance of the air-powered engine, namely specific mass flow and total energy efficiency. The lubricating experiment is carried out, three different lubricating oils, i.e. transformer oil, refrigerating oil and special oil are used. The experimental results show thatthe lubricating oil significantly influences the performance of the air-powered engine. When the water jacket is no water, or filled with room temperature water and hot water, the air-powered engine performance is studied. The experimental results show that the effect of heat exchange on engine per- formance is small and the multi-utilization of compressed air is helpful to enhance the total energy efficiency. To investigate the influence of valve timing on air-powered engine performance, three different inlet camshafts are used. The results of load characteristics and speed characteristics show that optimal per- formance is obtained when the inlet valve opening timing is 10 oCA before TDC. Under the condition of low engine speeds, the power performance and economy characteristic of air-powered engine are better.