Patent ID: 7217084
Filing Date: 2007-05-15
Classification: F04D

Abstract:
1. A fuel pump for a motor vehicle for pressurizing fuel to be delivered to an engine of said motor vehicle, said fuel pump comprising: a housing; an electric motor mounted in said housing and having a shaft defining an axial direction; a cover attached to said housing and having an internal cover surface defining a cover flow channel extending circumferentially around said internal cover surface, said cover including an inlet for coupling lower pressure fuel to said cover flow channel at an inlet end, said cover flow channel further including an outlet end providing higher pressure fuel; a body member coupled to said cover and having an internal body surface, said body member and said cover cooperatively defining a pumping chamber between said internal body surface and said internal cover surface, said internal body surface defining an outlet passageway to receive said higher pressure fuel for delivery to said engine; and a single-sided impeller mounted to said shaft for rotation therewith and for axial translation along said shaft within said pumping chamber, said single-sided impeller having a body-side surface and a cover-side surface, said cover-side surface defining an impeller flow channel extending circumferentially around said single-sided impeller juxtaposed with at least a major portion of said cover flow channel, said single-sided impeller including a plurality of vanes positioned at least partially within said impeller flow channel, said body-side surface having a plurality of discontinuous undercut regions each coaxially aligned with at least a portion of said impeller flow channel, said single-sided impeller having a plurality of apertures wherein each aperture connects said impeller flow channel with a respective undercut region, whereby pressure forces against said single-sided impeller from said fuel are substantially balanced in said axial direction.