Summary of the invention
The utility model purpose is the function that makes the hydraulic injection pump can realize torque limited among the OBD and still can makes Injection Pump stop oil spout when the stuck fault of Injection Pump generation pull bar to make engine misses.
The utility model adopts following technological scheme for achieving the above object:
A kind of Injection Pump that has automatically controlled fuel limit device comprises oil transfer pump, pump housing assembly, it is characterized in that: be provided with pressure controlled valve and automatically controlled limit fuel tap in the oil inlet passage between described oil transfer pump and pump housing assembly.
It is further characterized in that: described automatically controlled limit fuel tap is proportional electromagnetic valve, described proportional electromagnetic valve comprises piston, spring, armature, coil and housing, spring is installed in the piston back side, the piston lower edge is armature, coil is arranged at the armature below, spring force is opposite with the electromagnetic force direction, and case top is that the piston top is provided with filler opening, is provided with oil outlet in the piston head stroke range of housing side.
Further: the piston-top surface of described proportional electromagnetic valve has aperture, is communicated with internal piston and outside.
Its further feature also is: described pressure controlled valve comprises valve body, piston, compression spring, and the mesopore of perforation is arranged in the valve body, and described piston is installed in the mesopore, and the compression spring is installed in the piston back; The valve body bottom has an oil input channel, sidewall to have an oil road and a draining road to be communicated with mesopore, and oil road links to each other with automatically controlled limit fuel tap, and the draining road links to each other with fuel tank; Oil road and draining road are arranged on the described piston stroke, and the distance of draining track pitch valve body entrance is greater than the distance of oil road apart from the valve body entrance.
The utility model is installed a proportional electromagnetic valve at the oil inlet passage of pump housing assembly, regulates the aperture control fuel flow of proportional electromagnetic valve, thereby reaches the purpose of regulating the Injection Pump fuel delivery.And a pressure controlled valve has been installed between oil transfer pump and proportional electromagnetic valve has been made input pressure keep constant, to guarantee the linear ratio of aperture of fuel flow and proportional electromagnetic valve.
Embodiment
A kind of Injection Pump that has automatically controlled fuel limit device comprises oil transfer pump 1, pump housing assembly 4 as shown in Figure 1, at the oil outlet place of oil transfer pump 1 pressure controlled valve 2 has been installed, and proportional electromagnetic valve 3 is installed on the pump housing assembly 4.Fuel oil enters pressure controlled valve 2 from oil transfer pump 1, and the fuel oil that is adjusted into constant pressure through pressure controlled valve 2 is transported to proportional electromagnetic valve 3 by oil pipe (not drawing among the figure).
As shown in Figure 2, described proportional electromagnetic valve 3 comprises piston of electromagnetic valve 6, spring 7, armature, coil 5 and housing 8, spring 7 is installed in piston of electromagnetic valve 6 back sides, piston of electromagnetic valve 6 lower edges are armature, coil 5 is arranged at the armature below, spring force is opposite with the electromagnetic force direction, and housing 8 tops are that the piston top is provided with filler opening, are provided with oil outlet in the housing 8 side piston head stroke range.Piston of electromagnetic valve 6 end faces of described proportional electromagnetic valve have aperture, are communicated with internal piston and outside, make the suffered fluid pressure balance in piston two sides.
As shown in Figure 5, described pressure controlled valve 2 comprises valve body, piston 11, compression spring 12, and the mesopore of perforation is arranged in the valve body, and described piston 11 is installed in the mesopore, and compression spring 12 is installed in piston 11 backs; The valve body bottom has an oil input channel 9, sidewall to have oil road 10 and draining road 13 to be communicated with mesopore, and oil road 10 links to each other with proportional electromagnetic valve 3, and draining road 13 links to each other with fuel tank; Oil road 10 and draining road 13 are arranged on described piston 11 strokes, and 13 positions, draining road are higher than oil road 10.
Proportional electromagnetic valve 3 working principles are as follows:
Fig. 2: when the driving current of proportional electromagnetic valve 3 was the nominal operation value, coil 5 attracted piston of electromagnetic valve 6 to overcome spring 7 power and reaches range, valve wide open, and oil circuit is unblocked, and the fuel delivery of Injection Pump is unrestricted, can reach the maximum spout oil mass.
Fig. 3: reduce the driving current of proportional electromagnetic valve 3, electromagnetic force reduces, and balances each other with the spring force of spring 7 when a certain compression stroke, and the circulation area of oil circuit reduces, and has limited the fuel flow that enters Injection Pump, has namely limited the moment of torsion that diesel engine can reach.Because fuel pressure is steady state value, just can controls the fuel flow that enters Injection Pump by the aperture of regulating driving current value adjustment valve, thereby reach the purpose of accurate restriction diesel engine moment of torsion.
Fig. 4: when the driving current of proportional electromagnetic valve 3 was zero, piston of electromagnetic valve 6 is throttle down under the spring force effect, and oil circuit is blocked, and fuel oil can not enter Injection Pump, and Injection Pump is fuel feeding not, engine misses.
Pressure controlled valve 2 working principles are as follows:
Fig. 5: fuel oil enters the pressure controlled valve 2 from oil input channel 9, when the pressure of fuel oil is lower than initial tension of spring, can not jack-up piston 11, and fuel oil can not be confessed.
Fig. 6: when fuel pressure reached above initial tension of spring, compression spring 12 was compressed, jack-up piston 11, and fuel oil flows to proportional electromagnetic valve 3 from oil road 10.
Fig. 7: when fuel pressure was too high, compression spring 12 was further compressed, and draining road 13 is opened, and fuel flow returns is avoided overpressure to fuel tank.The cracking pressure of oil road 10 is P1, and the cracking pressure in draining road 13 is P2, remains greater than P1 less than P2 so supply with the fuel pressure of proportional electromagnetic valve 3.