Balanced pressure gerotor fuel pump

摘要

A gerotor pump (10) for pressurizing gasoline fuel is capable of developing pressures up to 2.0 MPa with good mechanical and volumetric efficiency and satisfying the durability requirements for an automotive fuel pump. The pump has been designed with optimized clearances (62,62,66,68) and by including features that promote the formation of lubricating films of pressurized fuel. Features of the improved pump (10) include the use of a shadow port (60) in the side plate (14) opposite the outlet port (56) to promote balancing of high fuel pressures on the opposite sides of the rotors. Inner (24) and outer (26) rotors have predetermined side clearances with the clearances (62,64) of the outer rotor being greater than those (66,68) of the inner rotor in order to promote fuel pressure balance on the sides of the outer rotor. Support of the inner rotor and a drive shaft on a single bushing (40) with bearing sleeves (42,44) maintains concentricity. Additional features are disclosed. <IMAGE>