Figure 1.40. High pressure fuel pump design
The booster pump with plunger and leakage sleeve supplies a certain dose of fuel to the distributor head with injection valves that open in accordance with the order of operation of the engine cylinders. The amount of fuel injected is determined by the position of the regulator lever, connected through the control lever and the system of rods and levers to the fuel supply control pedal. Each position of the control pedal corresponds to a certain position of the regulator lever.
The set mode is maintained by an all-mode centrifugal engine crankshaft speed regulator. If, at a set position of the regulator lever, the rotation speed increases for some reason, the centrifugal regulator weights diverge and the regulator shaft, overcoming the resistance force of the regulator lever spring, moves it in the direction of decreasing the amount of injected fuel.
If the rotation speed is accidentally reduced, the centrifugal regulator weights converge and the regulator lever is shifted under the action of the spring towards an increase in the amount of injected fuel. The moment of injection start is regulated by the rotation speed timer depending on the pressure created by the pump. The pump of this design provides for the correction of the volume of injected fuel depending on the pressure difference, i.e. depending on the elevation of the terrain above sea level. This task is performed by a diaphragm pressure difference compensator installed in the regulator cover. The pump provides the ability to adjust the engine crankshaft rotation speed in idle mode (adjusting screw), in full load mode (adjusting screw) and the maximum engine crankshaft speed (adjusting screw) by adjusting the volume of injected fuel using the appropriate adjusting screws. To stop the engine when the ignition is turned off, the pump design includes an electromagnetic valve to shut off the fuel supply. When the ignition is turned off, the valve shuts off the fuel supply. When the ignition is turned on by setting the ignition key to the ON position, the electromagnetic valve power supply circuit is closed, the valve stem is pulled in by the electromagnet and opens the fuel supply channel.
The high-pressure fuel pump is a precision device that requires special equipment and highly qualified service personnel for setup and adjustment. Any work with the high-pressure fuel pump in a garage can only by a lucky chance fail to result in a complete failure, so it is recommended that any work with the high-pressure fuel pump be performed only at a specialized enterprise.