回收排气余热能的气动-内燃复合循环理论研究

摘要

In order to improve the efficiency of internal combustion engine,a method of engine exhaust heat recovery through combined pneumatic and internal combustion cycle was proposed.This method used the mixture of exhaust gas and compressed air as working fluid of the pneumatic cycle.The mathematical model of combined cycle working process was built,and the it was used to analyze the influence of the main parameters on the combined cycle performance.The preliminary results show that increasing of the exhaust pressure of internal combustion engine,decreasing of the compressed air proportion,decreasing of the pneumatic engine rotation speed and the stroke/diameter ratio can lead to high exhaust heat recovery rate and high efficiency of combined cycle.The combined cycle can match the working fluid flow rates of the pneumatic cycle and the mixture gas through the regulation of the pneumatic engine rotation speed or the compressed air proportion.%为了提高内燃机能源利用率,提出一种回收排气余热能的气动-内燃复合循环方法,采用内燃机排气和压缩空气混合气作为气动循环工质,建立复合循环工作过程数学模型,分析其主要参数对循环性能的影响规律.研究结果表明:内燃机排气压力的增大、压缩空气占比的减小、气动发动机转速和行程/缸径比的减小均能提高内燃机排气利用率和复合循环效率.复合循环可通过调节气动循环转速或压缩空气占混合工质的比例来实现气动循环工质流量与混合工质流量的匹配.