What is the function of the oil pump?

The function of the gasoline pump is to supply fuel for each injector and cold start injector. There are two types of electric gasoline pumps used in electronic controlled gasoline injection systems: roller type electric gasoline pump and vane type electric gasoline pump. Roller type electric gasoline pump, one end of the pump shell is the oil inlet, the other end is the oil outlet. The roller pump on the side of the oil inlet is driven by a high speed drive motor in the middle of the pump housing. The rotor is mounted eccentrically in the pump body and the rollers are mounted in the grooves of the rotor.

When the oil pump rotates, due to the effect of centrifugal force, the roller in the rotor groove moves outward, closely against the eccentric design of the pump wall. At the same time, under the action of inertial force, the roller is always close to one side of the rotor groove, thus forming several working cavities. In the working process, the working chamber volume on one side of the oil inlet increases to become a low-pressure oil suction chamber, and gasoline is sucked into the working chamber through the oil inlet. The volume of the working chamber on the side of the oil outlet decreases and becomes a high-pressure oil chamber, from which the high-pressure gasoline flows out through the oil outlet.

There is a one-way valve at the oil outlet of the oil pump, which prevents the fuel from flowing back to the fuel tank when the oil pump is not working, so as to maintain the fuel pressure after the engine stops and facilitate the restart. The buffer at the oil outlet is used to reduce the oil pressure pulsation and running noise at the oil outlet. The maximum pump pressure of this kind of oil pump can reach above 0.45mpa. If the oil pressure on one side of the outlet of the oil pump is too high due to blockage of the gasoline filter and other reasons, the pressure limiting valve integrated with the oil pump is pushed open to make part of the fuel return to the side of the inlet to protect the electric gasoline pump.