车用发动机余热回收的新型联合热力循环

针对汽车发动机排气余热、冷却水余热和润滑油余热的特点,提出了一种新型的适用于车用发动机余热回收的热力循环系统.此系统由用来回收温度较高的发动机排气余热及润滑油余热的有机Rankine循环(Organic Rankine Cycle,ORC)和用来回收温度较低的发动机冷却水余热的Kalina循环耦合而成.基于P-R状态方程,编写了计算程序对此热力循环系统进行了热力学性能分析,还分析了采用不同有机工质对循环整体性能的影响.与传统的只回收发动机排气余热的热力循环系统相比,文中提出的构型其余热回收效率更高.当采用环戊烷为ORC工质时,循环系统的整体效率为20.83%;当采用R113为ORC工质时,循环系统的整体效率为16.51%.

A New Combined Thermodynamic Cycle for Waste Heat Recovery of Vehicle Engine

From the characteristics of waste heat in exhaust, cooling water and lubricant, a new thermodynamic cycle for waste heat recovery of vehicle engines was proposed. The present sys-tem consists of two cycles, organic Rankine cycle (ORC) for recovering the waste heat in high-temperature exhaust and lubricant and Kalina cycle for recovering the waste heat in low-tempera-ture cooling water. Based on P-R equation of state, the thermodynamic performance of the cycle was theoretically calculated with a self-written computing program. Then the overall performance of the cycle with different organic working fluids was analyzed individually. Compared with the conventional cycle configuration used for only recovering the exhaust heat, the present cycle has higher waste heat recovery efficiency. The overall efficiency of the cycle with cyclopentane and R113 is 20.83% and 16. 51%, respectively.