Exhaust Recovery of Vehicle Gasoline Engine Based on Organic Rankine Cycle 2011-01-1339
When the global energy consumption continues to increase, the research hotspot in the field of internal combustion engine (ICE) is how to improve the fuel utilization efficiency to achieve the energy saving. But as far as the engine efficiency is concerned, it has been very difficult to improve the fuel utilization efficiency after the Gasoline Direct-Injection (GDI) and Homogeneous Charge Compression Ignition (HCCI) technology were adopted.
In this study, the exothermic distribution of fuel was studied detailedly when a TOYOTA 8A-FE gasoline engine operated at different working conditions through conducting steady-state experiment. Only one third of fuel's chemical energy is converted into effective work by engine, the rest is released to the environment in the form of waste heat generated from cooling and exhaust gas. But except the waste heat that has to be released to the environment according to the second law of thermodynamics, the rest can be theoretically utilized. If the waste heat of the vehicle engine can be recovered, the engine efficiency will be evidently improved.
Results on the exergy analysis show that the exergy in the exhaust gas is about 45-70% and it will evidently increase with the increase of engine load and revolution. So it will have a good effect on exhaust recovery when the engine has a heavy load. Considering the character of exhaust gas, the Organic Rankine Cycle(ORC) is adopted to recover the waste heat of engine's exhaust gas. The thermodynamic performances of the cycle were analyzed and R113 was determined to be the working fluid.
The experimental exhaust gas recovery system used to testify the aforementioned theoretical calculation was designed and established. The system consists of exhaust gas simulation device, expander, condenser, dynamometer, pump and data acquisition and processing system. In experiment, the performance parameter and power output of the Organic Rankine Cycle were measured. The expander show a high isentropic efficiency and the experimental system show a practical thermal efficiency about 14.44%.