The core principle of the oil pump is to use mechanical movement to generate a pressure difference, thereby completing the suction and pressurized delivery of fuel. It can be specifically divided into electric fuel pumps, plunger oil pumps and new types of Venturi effect oil pumps:
I. Electric fuel pump
Working principle: The DC motor drives the rotor to rotate at high speed, driving the impeller to generate centrifugal force. When the impeller rotates, a vacuum low-pressure area is formed at the oil inlet to suck in the fuel, and after pressurization, it is delivered to the engine through the oil outlet.
Structural features:
It includes a pump body, a DC motor and a housing, and a sealing design is adopted to ensure stable pressure.
The graphite carbon brush contacts the commutator to achieve continuous power transmission.
II. Plunger oil pump
Oil suction and oil pressure process (taking the injection pump as an example):
Oil suction stage: When the plunger moves downward, the volume of the oil chamber increases to form a negative pressure, and the fuel enters the oil chamber through the oil inlet hole.
Oil pressure stage: The plunger moves upward to close the oil inlet hole, the oil pressure increases to open the oil outlet valve, and the fuel is pressed into the high-pressure oil pipe.
Oil volume adjustment: Control the oil supply by rotating the plunger to change the effective stroke length. For example, the longer the plunger bevel covers the oil return hole, the greater the oil supply.
3. New oil pump design (Venturi effect)
Combination of oil storage cup and venturi tube:
The oil pump draws oil from the oil storage cup, and part of the fuel generates negative pressure through the venturi tube, and the remaining fuel in the tank is drawn into the oil storage cup.
The oil storage cup always maintains sufficient fuel supply, and can still supply fuel stably even if the tank level is extremely low.
Advantage: Avoid the problem of traditional oil pumps failing to absorb oil when bumpy or low oil volume, and theoretically drain the last drop of oil in the tank.
4. Other types of oil pumps (supplement)
Gear pump: The gear meshing separation forms a low-pressure area to absorb oil, and the meshing extrusion forms a high-pressure area to discharge oil, but the noise is large and the efficiency is low.
Centrifugal pump: The impeller rotates at high speed to generate centrifugal force, converting the kinetic energy of the fuel into pressure energy output, and is often used in large flow scenarios.
