Patent ID: 7231910

Claim:
A fuel pump unit having first and second pump stages characterized in that the first pump stage has a suction connection ( 7 ) connected to a fuel tank ( 8 ) and a delivery connection ( 22 ), and in that the second pump stage has a suction connection ( 17 , 28 ) and a delivery connection ( 32 ) leading to the outlet ( 25 ) of the fuel pump unit, and having a two-way directional control valve ( 13 ) by means of which, in a first switching position, the delivery connection ( 22 ) of the first pump stage is connected to the outlet ( 25 ) of the fuel pump unit and the suction connection ( 17 ) of the second pump stage is connected to the fuel tank ( 8 ), and by means of the two-way directional control valve ( 13 ), in its second switching position, the delivery connection of the first pump stage is connected to the suction connection ( 28 ) of the second pump stage and in that the two-way directional control valve ( 13 ) has a first control slide valve ( 14 ) and a second control slide valve ( 19 ) which can be acted upon by the pressure in an outlet ( 25 ) of the fuel pump unit in a manner such that they can be moved, in each case counter to the force of a control spring ( 15 , 20 ), from their first switching position into their second switching position.