Fuel pump unit for motor vehicles - has two=stage pump system preventing formation of vapour bubbles

摘要

The fuel delivery system encloses pump system and its driving motor in a common housing. The first pump in two stage pump is a side channel pump and second one is a rolling cell pump. No flow interrupting vapour bubbles are formed in this pump. The nonuseful space between the housing inner part and the baseplate (8) of the first pump stage (3) in the region of the suction connection is reduced by a component (25). The latter is provided with a channel (26) which supplies fuel directly to the suction opening (23) of the pump (3). This component (25) is made of fuel resistant plastics and has bore (27) by means of which it is placed on a projection (22) of the baseplate (8) held within the housing.