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Returnless Fuel System

Purpose, outline

• Fuel evaporation in the fuel tank is reduced by adjusting the fuel amount (fuel pressure) ejected from the fuel pump and preventing fuel warmed in the engine compartment from returning.

System diagram

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Structure

• The returnless fuel system consists of the following parts:

Operation

• Fuel in the fuel tank is pumped out through the fuel filter (low-pressure) by the fuel pump, filtered by the fuel filter (high-pressure), and then regulated to a specified pressure by the pressure regulator. The regulated fuel is sent to the high pressure fuel pump, and unnecessary regulated fuel is returned from the pressure regulator to the fuel tank.

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Fuel Pump Unit

Purpose, function

• Supplies fuel in the fuel tank to the high pressure fuel pump.

• Based on the control signal from the PCM, the fuel pump operates by the operation of the fuel pump relay and the fuel pump control module.

• A brushless motor has been adopted in the fuel pump unit for improved fuel economy. Using the brushless motor, the fuel pump function is improved and a stabilized fuel supply is achieved.

Construction

• The fuel pump unit is installed to the fuel tank.

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• The fuel pump unit consists of a fuel pump, fuel filter (low-pressure) fuel filter (high-pressure), pressure regulator, and reserve cup.

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Operation

• Based on the control signal from the PCM, the fuel pump suctions fuel in the lower cover and pumps it to the high pressure fuel pump. After fuel is sufficiently filtered through the fuel filter (low-pressure) and fuel filter (high-pressure), fuel pressure is adjusted to approx. 500 kPa {5.10 kgf/cm², 72.5 psi} by the pressure regulator.

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• For fuel pump control details, refer to CONTROL SYSTEM. (See FUEL PUMP CONTROL [SKYACTIV-G (WITHOUT CYLINDER DEACTIVATION (US))].)