HIGH-PRESSURE FUEL PUMP
A high-pressure fuel pump includes a pump housing which defines a pumping chamber, a fuel inlet which allows low-pressure fuel into the pumping chamber, a fuel outlet which allows high-pressure fuel out of the pumping chamber, and a plunger bore which extends along an axis and opens into the pumping chamber. The high-pressure fuel pump also includes a pumping plunger which reciprocates within the plunger bore along the axis such that reciprocation of the pumping plunger within the plunger bore increase and decreases a volume of the pumping chamber. The pumping plunger includes a sealing ring groove which is concentric with the plunger bore, the sealing ring groove including a sealing ring therein which engages the plunger bore in an interference fit. A diametric clearance greater than 12 microns is provided between the pumping plunger and the plunger bore.
1 . A high-pressure fuel pump comprising:
a pump housing which defines a pumping chamber, a fuel inlet which allows low-pressure fuel into said pumping chamber, a fuel outlet which allows high-pressure fuel out of said pumping chamber, and a plunger bore which extends along an axis and opens into said pumping chamber; and
a pumping plunger which reciprocates within said plunger bore along said axis such that reciprocation of said pumping plunger within said plunger bore increase and decreases a volume of said pumping chamber, low-pressure fuel flows from said fuel inlet to said pumping chamber when said volume increases, and high-pressure fuel is discharged from said pumping chamber through said fuel outlet when said volume decreases;
wherein said pumping plunger includes a sealing ring groove which is concentric with said plunger bore, said sealing ring groove including a sealing ring therein which engages said plunger bore in an interference fit; and
wherein a diametric clearance greater than 12 microns is provided between said pumping plunger and said plunger bore.
2 . A high-pressure fuel pump as in claim 1 wherein said diametric clearance is in a range of 13 microns to 30 microns.
3 . A high-pressure fuel pump as in claim 1 wherein said sealing ring is held in radial compression by said pumping plunger and said plunger bore.
4 . A high-pressure fuel pump as in claim 2 wherein said sealing ring is held in axial compression within said sealing ring groove.
5 . A high-pressure fuel pump as in claim 1 wherein said sealing ring is held in axial compression within said sealing ring groove.
6 . A high-pressure fuel pump as in claim 1 wherein said pumping plunger also includes:
a second sealing ring groove which is concentric with said plunger bore, said second sealing ring groove including a second sealing ring therein which engages said plunger bore in an interference fit.
7 . A high-pressure fuel pump as in claim 1 wherein said sealing ring groove is annular.
8 . A high-pressure fuel pump as in claim 7 wherein said sealing ring is annular.