Delivery Valves For Fuel Pump is used in modern internal combustion engines to supply fuel from the fuel tank to the injectors. The pump should deliver fuel under high pressure, so that the nozzle can spray it into the engine. For the proper engine operation fuel pressure should be within allowed specifications for a given engine. Too low-pressure can lead to “fuel starvation” engine misfire, excessive vibration or stop the engine under load. Too much pressure causes uneven engine running too rich mixture, and excessive pollution.
Electric fuel pumps are usually install in fuel tank (intake), although some can installed outside. Some cars may equipped with two pumps (one pump inside the tank and the main pump on the outside). The location of the pump in the fuel tank helps mute the buzzing noise of pump’s electric motor. Submersion into the fuel helps lubricate and cool the pump’s engine. Driving with fuel tank filled with less than ¼ of its volume can shorten the life of the pump and cause rapid overheating. It also increases risk of pump left without of gas during rapid acceleration or deceleration.
The pump is usually part of a module that also includes a float that carries electrical signals to the level indicator, located on the dashboard. If the fuel pump needs replacing, it can replaced separately or the complete module assembly (it is expensive, but much easier).
Different electric fuel pumps have different designs. Some older designs used to use forced displacement of the circulation pump chamber. This type of pump can produce very high pressure and constant flow. But at the outlet of the fuel pump has been strong pressure fluctuations, so often in the gas line after the pump was install damper to reduce the amplitude of pulsation of gas pressure. Circulating chamber can also installed outside the tank. And used with the second low-pressure pump installed in the fuel tank.
There is another type of fuel pump – “rotor-type”. This design is similar to design of the oil pump and uses the offset rotor to push the fuel through the pump. Another variation of the roller pump – “vane-type”. The blades are use instead of rollers to push the gas through the pump. Most modern cars use a pump turbine. Blades of the impeller push gas through the pump. Turbine type pumps do not produce the pressure fluctuations these types are less complicated to manufacture and more reliable in operation. It is possible to replace a fuel pump by not original unit. In this case fuel pump’s output should be within original specifications and as consumption the same as the original one. Use of an improper specs can cause deterioration of performance of the car.