petrol pump
The function of the gasoline pump is to suck the gasoline out of the fuel tank and press it into the float chamber of the carburetor through the pipeline and the gasoline filter. It is thanks to the gasoline pump that the gasoline tank can be placed at the rear of the car away from the engine and below the engine.
Gasoline pumps can be divided into mechanically driven diaphragm type and electric driven type according to different driving methods.
Introduction
The function of the gasoline pump is to suck the gasoline out of the fuel tank and press it into the float chamber of the carburetor through the pipeline and the gasoline filter. It is thanks to the gasoline pump that the gasoline tank can be placed at the rear of the car away from the engine and below the engine.
Classification
Gasoline pumps can be divided into mechanically driven diaphragm type and electric driven type according to different driving methods.
Diaphragm gasoline pump
Diaphragm gasoline pump is a representative of mechanical gasoline pump. It is used in carburetor engine and is generally driven by the eccentric wheel on the camshaft. Its working conditions are:
① During the rotation of the oil suction camshaft, when the eccentric wheel pushes the rocker arm and pulls down the pump diaphragm pull rod, the pump diaphragm descends to generate suction, and the gasoline is sucked out from the fuel tank and enters the gasoline pump through the oil pipe, gasoline filter room.
②Pumping oil When the eccentric wheel rotates through a certain angle and no longer pushes the rocker arm, the spring of the pump membrane stretches, pushing the pump membrane up, and pressurizing gasoline from the oil outlet valve to the float chamber of the carburetor.
Diaphragm gasoline pumps are characterized by a simple structure, but because they are affected by the heat of the engine, special attention must be paid to ensuring the pumping performance at high temperatures and the durability of the rubber diaphragm against heat and oil.
Generally, the maximum fuel supply of a gasoline pump is 2.5 to 3.5 times greater than the maximum fuel consumption of a gasoline engine. When the pump oil volume is greater than the fuel consumption and the needle valve in the float chamber of the carburetor is closed, the pressure in the oil outlet pipeline of the oil pump increases, which reacts to the oil pump, shortening the stroke of the diaphragm or stopping the work.
electric gasoline pump
The electric gasoline pump does not rely on the camshaft to drive, but relies on the electromagnetic force to repeatedly suck the pump membrane. This kind of electric pump can freely choose the installation position, and can prevent air lock phenomenon.
The main installation types of electric gasoline pumps for gasoline injection engines are installed in the oil supply pipeline or in the gasoline tank. The former has a larger layout range, does not need a specially designed gasoline tank, and is easy to install and disassemble. However, the oil suction section of the oil pump is long, it is easy to generate air resistance, and the working noise is also relatively large. In addition, it is required that the oil pump must not leak. This type is rarely used in current new vehicles. The latter has simple fuel pipelines, low noise, and low requirements for multiple fuel leakage, which is the current main trend.
When working, the flow rate of the gasoline pump should not only provide the consumption required for the operation of the engine, but also ensure sufficient oil return flow to ensure the pressure stability and sufficient cooling of the fuel system.
