Fuel pump for an internal combustion engine

A pumping unit for a fuel pump of an internal combustion engine, comprising:

• a pumping plunger positioned in a bore extending along a longitudinal axis of the pumping unit to form a pumping chamber, the pumping plunger mounted for reciprocal movement through an intake stroke to receive fuel in the pumping chamber and a pressure stroke to pump fuel from the pumping chamber;
• an inlet check valve cavity;
• and
• an inlet check valve positioned in the inlet check valve cavity, the inlet check valve including an inlet check valve plunger mounted for reciprocal movement in the inlet check valve cavity, the inlet check valve cavity being positioned to receive an inlet flow of fuel for delivery to the pumping chamber during the pumping plunger intake stroke and positioned to receive a flow of high-pressure fuel from the pumping chamber during the pumping plunger pressure stroke, and the inlet check valve plunger includes a passage to receive high-pressure fuel during the pumping plunger pressure stroke.

A fuel pump for an internal combustion engine, comprising:

• a bore;
• a pumping plunger positioned in the bore to form a pumping chamber;
• a high-pressure fuel outlet;
• an inlet fuel circuit connected to the pumping chamber to provide an inlet flow of fuel to the pumping chamber;
• an outlet fuel circuit connecting the pumping chamber to the high-pressure fuel outlet to provide an outlet flow of high-pressure fuel from the pumping chamber;
• an outlet check valve positioned along the outlet fuel circuit downstream from the pumping chamber and upstream from the high-pressure fuel outlet;
• and
• an inlet check valve positioned along the inlet fuel circuit upstream from the pumping chamber to receive fuel for delivery to the pumping chamber during the pumping plunger intake stroke and positioned along the outlet fuel circuit upstream from the outlet check valve and downstream from the pumping chamber to receive high-pressure fuel from the pumping chamber during the pumping plunger pressure stroke.