Fuel Pump and Fuel Level Sensor Assembly

FUEL PUMP AND FUEL LEVEL SENSOR ASSEMBLY

FUEL PUMP
The fuel pump consists of a motor, impeller, pump casing, pump cover, check valve and filter. It is located in the fuel tank and combined with the fuel level sensor and fuel temperature sensor into a single unit. The operation of this impeller type pump is very quiet.
- When the ignition switch is turned ON, fuel pump relay is activated. Then the motor operates to rotate the impeller.
- As the impeller rotates, fuel in a vane groove of the impeller flows along the fuel passage into the next vane groove by centrifugal force. When fuel flows from one groove to the next, a pressure difference occurs due to friction. This creates a pumping effect.
- The fuel pushed up by rotation of the impeller then passes through the clearance between the armature and the magnet of the motor and is discharged through the check valve.
- When the fuel discharge pressure reaches the specified level, the relief valve opens and excess fuel is released into the fuel tank.In this manner, the relief valve prevents an abnormal increase in fuel pressure.
- When the engine and the fuel pump stop, the check valve operates to close the discharge port, so that the fuel pressure in the fuel delivery line is retained.

FUEL LEVEL SENSOR




The fuel level sensor is integrated with the fuel pump, which is located in the fuel tank. The sensor outputs an electric resistance signal that varies with movement of its float to indicate the level of the fuel remaining in the tank.

JET PUMP




- The jet pump utilizes the velocity of fuel returning from the engine to produce vacuum in it.
- Using the pumping effect produced by the vacuum, the jet pump transfers fuel from the sub-compartment and main compartment of the fuel tank to the fuel pump.
- When the return line nozzle is clogged, the fuel sent back through the return line flows back into the fuel tank via the relief valve.

FUEL FILTER
The fuel filter is integrated with the fuel pump assembly, which is located in the fuel tank.