Electric Fuel Pump
Civic & Prelude
The fuel pump is an in-line, direct drive type. Fuel is drawn into the pump through a filter, flows around the armature through a one-way valve and is delivered to the engine compartment. A baffle is provided to prevent fuel pulsation.
The fuel pump has a relief valve to prevent excessive pressure. It opens if there is a blockage in the discharge side. When the relief valve opens, fuel only flows from the high pressure side to the low pressure side. A check valve is used to maintain fuel pressure in the line after the pump is stopped to ease restarting.
The pump consists of a rotor and rollers. See Fig 1 . When the rotor turns, the rollers turn and travel along the inner surface of the pump spacer by centrifugal force. The volume of the cavity enclosed by these 3 parts changes, drawing and pressurizing fuel.
Accord
The fuel pump is installed inside the fuel tank. The fuel pump is comprised of a DC motor, a circumference flow pump, a relief valve for protecting the fuel line systems, a check valve for retaining residual pressure, an inlet port, and a discharge port.
When the engine is started, the main relay actuates the pump, and the motor turns together with the impeller. If fuel flow is obstructed at the discharge side of the fuel line, the relief valve will open to by-pass the fuel to the inlet port and prevent excessive fuel pressure. When the engine stops, the pump stops automatically. A check valve closes after engine stops to retain the residual pressure in the line, helping the engine to restart more easily.