Development Of Test System For ICE Exhaust Gas Energy Recovery Based On Rankine Cycle

As the growth of automobile population, huge amounts of oil was consumed each year. Before new energy vehicle replaces traditional automobile, improving the efficiency of internal combustion engine is an important approach to ease the energy crisis. Some scientists have begun to do research on recovering energy from exhaust gas which contains one third energy of the fuel and Rankine cycle is an effective approach. Relevant experiments have been done by several foreign companies and research institutions.This paper develops an exhaust gas energy recovery testing system based on rankine cycle on the basis of a four cylinder diesel engine. The computational formula of diesel-rankine combined cycle was deduced according to the principles and working process of rankine cycle. Then the factors of combined cycle's efficiency was analyzed. This paper creates a GT-POWER simulation model of the engine used in the testing system. After the confirming the accuracy of the model by experiment, the relation between the engine's power output and back pressure was analyzed. This consequence is useful in waste heat recovery heat exchanger design. High initial pressure and temperature of rankine cycle leads to high efficiency. The experiment condition determined the parameters and working fluid of rankine cycle finally.The study shows that heat transfer area increases faster than steam output. So a relatively high exhaust gas temperature at the outlet of steam evaporator was preferred. According to appropriate design steps, evaporator used in the testing system was designed. This paper also investigates the heat exchangers'performance vary with flow rate and temperature of exhaust gas.Experiments confirmed the security and performance of the experiment system. The steam turbine's rotate speed reach 3800 r/min in the system testing.