Experimental Investigation And Chemical Kinetics Simulation On Microwave Ignition For IC Engine

Microwave Ignition is an innovative ignition method with great promisingto achieve high efficiency-clean combustion and expand combustion lean limithighly in internal combustion engines. The technique of Microwave Ignition isnot mature and the working mechanism of Microwave Ignition is not clearcurrently. The project is from the National Science Fundamental Project whichnamed “Experimental and Theoretical Research on Microwave ignition used inIC Engine”. A new microwave plasma-aided-combustion chemical reactionkinetics model was built, and the performance test of a novel Microwave SpaceIgnition method was conducted.Reviewing the studies on microwave ignition for IC engine, it can bedivided into three categories according to ignition method.1) MTI (Microwaveresonator Torch Ignition).2) MAI (Microwave plasma Assisted Ignition).3)MSI (Microwave resonance Space Ignition). All the detail ignition method andcharacteristic was analyzed, and the probably mechanism of microwave ignitionhas been discussed.In this study, a microwave ignition system was developed. Successfulmicrowave ignition in CH4/Air mixture was achieved using microwave plasmaproduced by microwave resonance in a combustion chamber, both thevisualization test and combustion properties test was carried out. Themicrowave is produced by a magnetron microwave source, and the frequency is2.45GHz. It shows that large area of non thermal plasma kernel was generatedwith microwave coupling when the initial pressure of the mixture is less than0.3MPa. The performance of microwave ignition with different equivalenceratio, different initial pressure, and different power supply was study in thispaper. The result shows that the pressure of the mixture has a significant impacton the property of microwave ignition. The CH4/Air mixture with higherpressure would be more difficult to be breakout by microwave. Currently, whenthe mean microwave power is300W, the performance of microwave ignition isnot as good as the traditional spark ignition when the pressure is higher than0.2MPa, while when the pressure is lower than o.2MPa，the performance is almost the same as spark ignition.To obtain chemical mechanistic information relevant to the microwaveignition behavior, the plasma-aided-combustion model, including electron, ions,radicals and molecules was established, which consist of three parts: GRI3.0mechanism, Warnatz ions mechanism, and O3mechanism. The acceleration ofhomogeneous mixture combustion with various active particles (plasmas,radicals and species) which are most likely to be generated and heating energieswas compared under the different working condition. The results show that theplasma O+&e accelerates combustion process mostly. Judging from analysis ofchemical reaction path, the plasmas change the initial chemical reaction path.As a result, hydrocarbon combustion was significantly accelerated.