Combined vacuum and engine fuel pump - has vacuum and fuel pump pistons with common drive, one driving fuel pump diaphragm via air chamber

摘要

The mechanically driven pump combination is intended for generating a vacuum and feeding fuel to a motor vehicle engine. It comprises a common housing (1) containing a crank-driven (3) piston (4) in the pump chamber (5) of the vacuum pump (6), and a second piston (9) with axial throttle passage (14), also driven by the crank. The second piston reciprocates in an air-filled chamber (10) which acts as pneumatic spring and is separated from the fuel pump (12) chamber (11) by a diaphragm (13). The two pistons may be interconnected via a cup-shaped element (2). The pump may have two diaphragms instead of pistons.