FUEL PUMP UNIT CONSTRUCTION/OPERATION [L8, LF, L5]


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Fuel Pump Unit

•  Mainly consists of a fuel filter (high-pressure), pressure regulator, fuel pump, fuel reserve cup, and fuel filter (low-pressure).
•  A pressure regulator is built-in due to the adoption of a returnless fuel system.
•  A hard-plastic fuel pump unit, with an integrated fuel filter (high-pressure) and fuel pump, has been adopted to simplify the fuel line.
•  Fuel in the fuel reserve cup is suctioned out through the fuel filter (low-pressure) by the fuel pump, and pumped to the fuel filter (high-pressure). Return fuel is sent back to the fuel reserve cup or the fuel tank through the jet pump.
•  Fuel in the fuel reserve cup is suctioned out through the fuel filter (low-pressure) by the fuel pump, and pumped to the fuel filter (high-pressure). Return fuel is sent back to the fuel reserve cup or the fuel tank through the jet pump.

Pressure Regulator

•  Built into the fuel pump unit due to adoption of a returnless fuel system.
•  Mainly consists of a spring, release valve and diaphragm.
•  Pressurizes fuel discharged by the fuel pump to approx. 390 kPa {3.98 kgf/cm2, 56.6 psi} using the spring, diaphragm and release valve, and then pumps it to the fuel distributor.
•  If fuel pressure exceeds approx. 390 kPa {3.98 kgf/cm2, 56.6 psi}, the release valve opens to discharge unnecessary fuel pressure.