Experiment Research On RM-HCCI Combustion Based On Plasma High Temperature Anaerobic Fuel Reforming

In the face of energy and environment problems,increasing the thermal efficiency of internal combustion engines and reducing emissions have become the hotspot in the world.In this paper,a new combustion mode reformed molecule HCCI(RM-HCCI)combustion was proposed for the purpose of achieving high thermal efficiency and low emission of engine.According to the demand of high temperature anaerobic fuel reforming HCCI combustion theory,a test device of plasma fuel reformer was designed and built.It was carried in a single-cylinder engine testbench with a compression ratio of 17 and it was subjected to RM-HCCI combustion experiment to explore the law of high thermal efficiency and low emission.In order to meet the test demand of fuel reforming,this paper innovatively designed a plasma fuel reformer with a compact and simple structure,and fast thermal response.For the key components of the device,the external characteristics of the plasma power supply were studied from the aspects of the arc control method.In this paper,the structure and thermal management of the fuel reformer were designed.The cooling water jacket was designed for the plasma generating electrode in the device.The temperature field and velocity field of the cooling water jacket were simulated by Ansys fluent,the conclusions indicated that the simulation fited well with the actual,the cooling effect was well.In order to verify the advantages of RM-HCCI combustion in energy saving and emission reduction,N-heptane fuel was reformed under the reforming temperature of 1050 K of high temperature anaerobic reforming condition and the reformed gas was injected into the engine to control HCCI combustion.The combustion and emission performance of different HCCI combustion from non-reformed fuel and reformed fuel were compared.In comparison with non-reformed gasoline HCCI(G-HCCI)combustion,RM-HCCI combustion that used the reformed n-heptane underwent a later burning start point,faster burning rate,lower heat transfer loss and higher indicated thermal efficiency.For further exploration of high thermal efficiency and low emission law of RM-HCCI combustion,the influence of engine boundary parameters on the combustion and emissions of RM-HCCI were researched.Increasing EGR or reducing the intake air temperature had similar effects.The combustion rate slowed down,the combustion starting point CA10 and combustion phase CA50 were postponed,the combustion duration prolonged,indicating that the thermal efficiency decreased to some extent,and the CO and HC would follow the boundary parameter to increase,NOx would be reduced.The highest indicated thermal efficiency of RM-HCCI reached 53.9% among all the operating points listed through the optimization of indicated thermal efficiency,and at the same time the thermal efficiency of most operating conditions reached more than 52%,and the NOx emission was low at this time.But the maximum indicated thermal efficiency of the G-HCCI only reached 50.5%.This fully illustrated the advantages of RM-HCCI combustion with high efficiency and low emissions.