Working Process Study On Air-powered And Diesel Hybrid Engine

Due to the pressure of energy saving and environmental protection, people have been making greater and greater efforts on seeking alternative energy source. In this research field, air-powered engine (APE), which using compressed air or liquid nitrogen as its working medium with none combustion and none pollution, has been received a great attention. But restricted by energy density and its translate efficiency, APE has its own disadvantages in power and continues distance of driving, which are just the advantages of internal combustion engine (ICE). So combining APE and ICE to form a new type of hybrid engine, can be an effective solution to solve the conflict above.In this thesis, a series of theoretical and experimental study were carried out, detailed as follow:Numerical simulation on working process of APE A nicety model on in-cylinder process of APE was made on basis of variable mass thermodynamics and flow field analysis. With this model, cylinder structure, valve system, operation parameters'influences on dynamic and economical characteristics of APE were discussed according to local and global sensitive analysis.Numerical simulation on air-powered and diesel hybrid engine Couple models of subsystem such as APE, ICE, heat exchanger and so on, to form the completed theoretical model of air-powered and diesel hybrid engine. Numerical simulation results on this model show working process, exergy distributing, performance and feasibility of the hybrid engine system.Optimization on matching of hybrid engine In allusion on different economical guideline of hybrid engine, corresponding air management principle was brought in and numerical simulation study was carried out, in order to reach the best matching between air-powered cylinder and diesel cylinder of hybrid engine.Experimental study on hybrid system Connect APE and a diesel engine to form the hybrid system, heat up inlet air of APE by exhaust gas of diesel with an heat exchanger. Test-bench on this hybrid system was established and the performance of which was tested. The results of experimental study show the influence on APE and diesel by this connection, and the feasibility was proofed.Chief conclusions of the thesis are:1, States of air in APE are symmetrical.2, Parameters of inlet vavle play the most important part in APE's performance. 3, Exhaust and turbulence are two primary factors resulting the exergy loss of inlet air.4, Form hybrid system, reclaim the exhaust energy of traditional ICE to heat up inlet air of APE, is an effective and feasible way to improve the performance of APE.5, Results of both simulation and experimental show the chief purpose of designing this air-powered and diesel engine, can be achieved. Dynamic and economical characteristics of APE can be improved greatly without worsen the performance of diesel obviously, and the ideal work range of APE can be expanded as a plus.The thesis established numerical simulation and experimental study plat roof of air-powered and diesel hybrid engine, validated feasibility of this hybrid, made a good foundation for the further research.