The pneumatic and internal combustion combined cycle was proposed in order to recycle the exhaust heat of internal combustion engine. The exhaust valve open timing was advanced in this combined cycle,which can raise the exhaust pressure and lead to smoothly full mix of compressed air and exhaust gas. The p-V diagram of combined cycle was built based on the thermodynamics theory, and it was used to analyze the working process and cycle efficiency. The cycle efficiency was preliminarily calculated. Results show that the first law and second law thermodynamics efficiency grow in the beginning and decrease with the increasing of the exhaust valve open timing. The optimum exhaust valve open timing drops as the internal combustion engine speed increases, while the first law and second law thermodynamics efficiency of combined cycle increase in the same condition, but with its increasing rate falling gradually.
XU Huan-xiang, LI Dao-fei, WANG Lei, YE Jin, FAN Zhi-peng, YU Xiao-li. Efficiency analysis of pneumatic and internal combustion combined cycle for exhaust heat recycle. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2014, 48(4): 649-652.
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