Fuel pump

Fuel pump or also known as Fuel Pump is one of the components in the fuel system on a vehicle or other internal combustion engines. Some machines do not require a fuel pump because of its design and the gravity, the fuel will flow by itself in the fuel system. Most of the others had to use pumps to drain the fuel from the fuel tank. In using a carburetor engine, generally using low-pressure mechanical pump mounted outside the fuel tank while engine with fuel injection, some have 2 kinds of pumps in the fuel delivery system,

1. Medium pressure fuel pump / large volume tank or better known as the Fuel Pump. This pump works to supply the fuel injection system. Generally electric pump mounted in the fuel tank.
2. Pump high pressure / low volume or better known as the Fuel Injection Pump (FIP). This pump is in the fuel injection system to pump the fuel to function in a high pressure fuel to supply to the injector.

Most fuel-injected engines do not have fuel pumps. Fuel injection systems suck fuel directly from the tank or FIP pumping fuel from the tank into the injector.

Fuel pump has two types:

1. Mechanical fuel pump. 
2. Electric fuel pump.

Mechanical fuel pump

design

Much of this type of pump is the type of membrane pump. Membrane pump has a pump chamber whose volume depends on the elasticity of the membrane movement. In addition, it is equipped with one-way valve at the inlet and the outlet. Specific designs vary widely, these pumps are generally mounted on the engine block or cylinder head. A shaft with an eccentric shaft and connected to the engine will move the lever on the pump (directly or through axle suppressor / liaison) to move up and down with the movement of the membrane. This movement will make the pump chamber volume will shrink or enlarge, and repeated according to engine speed. When the pump chamber volume decreases, the pump chamber pressure will increase and result in one-way valve on the outlet open as well as one-way valve at the inlet is closed, fuel is pumped out through the channel going out. When the volume of the gas changes from the smallest becoming enlarged, the pump pressure will decrease and result in one-way valve on the outlet is closed and the one-way valve at the inlet open, bajar be sucked material enters the pump through the inlet. When this process occurs continuously, the fuel will flow from the tank into the carburetor or fuel injection system. Mechanical fuel pump pressure generally results in no more than 15 psi, qualified as a low pressure pump. 

Electric fuel pump 

General electric fuel pump mounted on the fuel tank, a small pump installed in the machine. Depending on the design, this type of pump produces pressure varies, from a low-pressure pump up high enough. Some are equipped with sensors to detect the load (supply) excess, which will turn off the pump works because there is generally no channels to flow back to the fuel tank.

application

Modern vehicles especially those already using a fuel injection system, generally using electric fuel pump because:

> It is easier synergy with other systems, eg with the electronic control unit.
> Injection pump will work more effectively if the incoming fuel injection pump in pressurized circumstances sufficient.