| As an accurate instrument, electromagnetic valve injector is the key execution mechanism of electronic-controlled fuel spraying system of auto engine. It receive the fuel spraying signals from the engine's electronic-controlled unit ECU, accurate calculate the fuel spraying amount and spraying time, and spray the fuel particle from distribution pipe to each entrance end to form fuel pulverization combination gas. In this paper the key manufacture technologies of electromagnetic valve injectors of auto engine were detailed researched, the special stainless steel materials YlCr17TiRe used for manufacture of electromagnetic valve injector were developed, the reasonable structure of electromagnetic valve injector was designed, and the application material for manufacture of upper and lower tubes, injector hole plat, pulverization hole plate and injector base were detailed, all components above used the special developed stainless steel Y1Cr17TiRe, co-yoke flake of fuel injector choose iron-nickel alloy 1J50, and spring was made of stainless steel 1Cr18Ni9Ti. After detailed researches on the key manufacture technologies of electromagnetic valve injector of auto engine, main conclusions were summarized as follow:The special stainless steel material YlCr17TiRe used for manufacture of electromagnetic valve injector was developed for the first time in domestic, and the influence of heat treatment temperature upon material organization and magnetic properties was detailed researched. The microscopic structure of casting stainless YlCr17TiRe and of annealing of 420℃is of martenitic. And the most convenient heat treatment process parameters of YlCr17TiRe are: 860℃of heating preservation temperature,3 hours of holding time and cooling in furnace. The stainless material YlCr17TiRe after heat treatment represented ferritic structure of base with tiny Cr-carbonates particles, and the magnetic properties raised a little but not obvious.The best heat treatment process parameters of iron-nickel alloy IJ50 are:300℃/Hour of heating velocity to 1100℃,3 hours of holding time and 200℃/H of cooling velocity to 350℃,and with rapid cooling opening the furnace. The Fe-Ni alloy IJ50 processed crystal order change after 350℃heat treatment, the plan-less and jumbled atoms of Fe and Ni changed to in order of particle of Ni3Fe. After heat treatment, sensitivity of material react to magnetic field was stronger, in a smaller magnetic field strength situation, materials magnetic induction can be quickly reached saturated, and the saturation magnetic induction intensity has significantly improved. After heat treatment, the inductance of magnetic properties increased significantly too.The special laser welding equipment and addendum modification equipment were designed which can satisfy the structural design of electromagnetic valve injector in fuel engine,and the equipments can ensure the assembly error of injector system was limited to 0.01mm. The structural of electromagnetic valve injector was simple, and the design of ball valve form greatly reduced the weight of coupling valve, so that the injector can be opened and closed faster and accurately with a less electro-magnetic force, which formulated the 7 welding and assemblage processes which formed the key know-how points of manufacture of engine's injector.The laser pulse welding process parameters of engine's fuel injector for car had systematically researched for the first time, and analyzed in detail the effect of welding parameters to the fusion characteristics. After a plenty of test and research, the convenient optimization parameters to get the perfect welding bond for most welding seam has been found as follow:welding current 110-130A, focus length -1mm, pulse width 2.0-2.5ms, frequency 60HZ, welding velocity 600mm/min. The best welding parameters for the conjugate flake of Fe-Ni alloy, that is welding seam No.7, has been found as follow: welding current 120A, focus length -1mm, pulse width 5.2ms, frequency 3 HZ, welding velocity 80mm/min. The best welding seam can be got under the process parameters.The micro-structure properties of welding seam was researched. The main micro-structural of fusion zone is austenite dendrite, and the seam centre is equiaxed crystal, while between the two areas is the mixture of austenite dendrite and equiaxed crystal. Some layered phenomenon was discovered in the welding seam microstructure. The characteristics of layered phenomenon have been explained with the calculation of laser welding overlapping and flow characteristics of liquid pool metal. When the power density of pulse peak increased, the weld seam appeared surface depression, pores, cracks and other defects.A detail analysis on the opening and closing processes of injector valve has been carried out, a mathematical calculation model of injector valve has been established,and with the model the time to open or close the injector can be calculated. The opening process of fuel injector can be divided into several parts:such as the resort force,the valve course,the working voltage of electromagnetic valve, the solenoid number and the solenoid resistance has been carried out based on this software. The dynamic opening process of injector has been analyzed in theory and verified in practice. And the calculation formulas of the two opening and closing processes had been established.The whole experiments such as pulverization errors, pulverization quality, reliabilities, properties of high and low temperature of fuel injector had been engaged, which proved be exactly conformed to the state relative standards. The opening time of injector is 1.1ms, with error interior of 3%. The pulse width of 3ms with 2700 times of pulverization was conformed the design standards. In pulverization experiment, the fuel particles presents in foam without fuel column which conformed. In experiments of reliabilities, properties of high and low temperature of fuel injector engaged, after respected 8 hours of temperature 120℃high and -30℃low, and 5.4 X 105 cycles of pulverization experiments, the fuel injector worked very well without any abnormal phenomena which comparing favorably with the world's advanced technologies.
|
PDF Full Text Request