Research On RCCI Combustion And Emission Performance Of Gasoline/diesel Dual-fuel Engine

As environmental pollution and energy shortages become more and more prominent,key technologies for energy conservation and emission reduction have become hot and difficult issues in the field of power machinery.Reactivity Controlled Compression Ignition?RCCI?technology combines two different reactive fuels to achieve effective control of combustion phase and heat release rate,while maintaining high thermal efficiency while reducing NOx and PM emissions from diesel engines.The gasoline/diesel dual-fuel engine can effectively control the premixed combustion process and the diffusion combustion process to realize the RCCI combustion mode.Therefore,research on the combustion a nd emission process of the dual fuel engine is of great significance for achieving efficient and low pollution combustion of the engine.Based on the in-depth analysis of the physicochemical properties of gasoline and the blending mechanism of gasoline and diesel,the project reconstructed the intake system of a 4-cylinder high-pressure common rail electronically controlled diesel engine and designed a multi-port manifold.The structural scheme of point-sequential injection of gasoline.By analyzing the fun ctional requirements of the dual fuel control system,the control strategy of the gasoline injector was designed.The cylinder operating sequence and gasoline injection sequence for the dual fuel engine are determined.Based on the self-developed dual fuel control system and gasoline injection system,the effects of different gasoline blending ratios on the combustion and emission characteristics of diesel engines under different operating conditions were studied.Research indicates:?1?The designed gasoline/diesel dual fuel control system can reliably switch between the two modes.The gasoline and diesel injection quantities can be coordinated and controlled according to different operating conditions to realize the gasoline/diesel dual fuel RCCI combustio n mode.?2?When the dual fuel mode is adopted,the engine can maintain the power of the original pure diesel engine as the gasoline blending ratio increases;at medium and high loads,as the gasoline blending ratio increases,the effective fuel consumptio n decreases,and when the gasoline blend ratio is 30%⁴0%,effectively reducing fuel consumption by 3%to 6%,high load operation dual fuel mode,the economic advantage of significantly enhance engine.?3?As the gasoline blending ratio increases,the peak cylinder pressure increases,and the peak cylinder pressure increases by 22%when the gasoline blending ratio is increased from 0%to 30%.?4?At medium and high speeds,as the gasoline blending ratio increases,the emission index decreases.When the gaso line blending ratio increases from 0%to 40%,CO₂ emissions are reduced by 8%,smoke emissions are reduced by 50%,and NOX emissions are reduced by 30%smaller;dual fuel mode can effectively reduce CO ₂,smoke and NOx emissions.?5?At medium and small loads,THC?CH₄ and CO emissions are higher than the original machine.When the gasoline blending ratio is increased from 0%to 40%,the emission increase is obvious;t Dual fuel mode emits lower THC,CH4 and CO at medium to high and medium high speeds,and the increase in emissions is less when the gasoline blending ratio is increased from 0%to 40%.