| As the domestic diesel locomotive diesel engine power unceasingly strengthens,the prototype 16V280ZJ diesel engine fuel injector in the practical work in oil leakage,atomization,gradually,and even the phenomenon such as needle valve jammed,its failure reason mainly has long needle valve of impact stress of needle valve seal seat surface is higher,fuel flow cross-sectional area is larger,and severe needle valve and spray pressure drop,etc.Therefore,in order to improve the impact stress on the seal seat of the needle valve body of the prototype injector,improve the fuel injection pressure and fuel atomization quality,this paper puts forward an improvement scheme on the basis of the original16V280ZJ diesel engine injector,and develops a new type of short-needle valve injector.The specific work contents are as follows:The theoretical empirical formula is used to design and calculate.The calculation results show that the cross-sectional area of fuel flow of the new injector is reduced by 0.758 mm~2,the impact stress of the needle valve sealing seat is reduced by 111.022 MPa,and the working pressure of the spring is increased by 30.4 N.Through finite element analysis software,the collision simulation of the needle valve couple of the new fuel injector is carried out,and the collision life of the needle valve couple is predicted.The simulation results show that the maximum impact stress is 815.29 MPa,the maximum deformation is 0.498mm,and the service life reaches 6536 h;The finite element analysis software was used to simulate the maximum stress and deformation of the new type of needle valve coupling under normal working environment.The simulation results show that the maximum equivalent stress of the new type of needle valve is 117.21 MPa,and the maximum deformation is 0.11515 mm;The maximum equivalent stress of the new type needle valve body is 209.01 MPa and the maximum deformation is 0.171 mm,which meets the requirements of working intensity.The fluid analysis software was used to simulate the fuel flow field inside the injector before and after the improvement.The simulation results show that the cavitation phenomenon is improved,and the fuel injection pressure is increased by 5 MPa;The fuel velocity at the outlet of the nozzle is increased by 7 m/s,which improves the atomization quality of the fuel.The new type of short-needle valve injector not only improves the reliability of the injector,fuel injection pressure,fuel atomization quality and fuel flow capacity,but also reduces the fuel consumption and pollutant emission of the diesel engine,bringing remarkable economic and social benefits. |
