Fuel Pump: Description and Operation

Suction Jet Pump, Function


NOTE: The arrow points in direction of travel.







On vehicles with four-wheel drive the fuel tank is divided into a left and a right chamber.

The fuel is delivered from the left fuel tank chamber to the baffle housing -8- of the fuel delivery unit in the right fuel tank chamber by means of a suction jet pump -1-.

A second suction jet pump -7- is located in the right fuel tank chamber and serves to improve the fuel delivery in the right fuel tank chamber to the baffle housing of the fuel delivery unit.

The suction jet pumps operate according to the principle of fluid entrainment: a stream of fuel from the fuel return pipe -3- is passed through a nozzle in each individual suction jet pump -1- and -7-, and is thus accelerated. The accelerated stream of fuel draws off the surrounding fuel and delivers it to the baffle housing of the fuel delivery unit. The right suction jet pump -7- delivers the fuel directly into the baffle housing, the left suction jet pump -1- delivers the fuel via a separate pipe -4-.

The fuel is distributed from the return pipe to the two suction jet pumps via the Y-connector -2-.

At the same time the connecting piece -6- limits the pressure in the lines to the suction jet pumps to approx. 1 bar. Excess fuel is delivered directly to the baffle housing via a pipe.

5 - Fuel supply line