Nonreturn Valve Construction/Operation; Returnless Fuel System Outline; Features; Returnless Fuel System Operation - Mazda RX-8 2004 Service Highlights

NONRETURN VALVE CONSTRUCTION/OPERATION

• A single valve type has been adopted.
• The nonreturn valve cannot be removed because it is fixed to the fuel-filler pipe in the fuel tank.
• Under normal conditions, this valve is closed as shown by the dotted line. When refueling, it opens to the
position shown by the solid line due to the flow of fuel. When refueling is finished, the valve returns to the
normal valve position due to spring force.
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RETURNLESS FUEL SYSTEM OUTLINE

Features

• The returnless fuel system reduces fuel evaporation in the fuel tank.
• The pressure regulator located in the fuel tank prevents fuel return from the engine compartment side, thereby
maintaining a low fuel tank temperature. Due to this, formation of evaporative gas produced by a rise in fuel
temperature is suppressed.
• The pressure regulator is built into the fuel pump unit in the fuel tank.
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RETURNLESS FUEL SYSTEM OPERATION

• Fuel in the fuel tank is pumped out through the fuel filter (low-pressure side) by the fuel pump, filtered by the
fuel filter (high-pressure side), and then compressed to a specified pressure by the pressure regulator. The
pressurized fuel passes through the pulsation damper and is sent to the fuel injector.
• The pressure regulator pressurizes fuel to approx. 390 kPa {3.98 kgf/cm
the approx. 390 kPa {3.98 kgf/cm
allow fuel to flow to the fuel tank.
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01–14–4
FUEL SYSTEM
NONRETURN VALVE
VALVE POSITION DURING
REFUELING
FUEL TANK SIDE
NORMAL VALVE POSITION
2
, 56.6 psi}, the pressure regulator valve in the fuel pump unit opens to
FUEL TANK
FUEL
FUEL-FILLER PIPE
2
, 56.6 psi}. If the pressure exceeds
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