Combination outlet valve and pressure relief valve and fuel pump using the same

A fuel pump comprising:

• a fuel pump housing with a pumping chamber defined therein;
• a pumping plunger which reciprocates within a plunger bore along a plunger bore axis such that an intake stroke of said pumping plunger increases volume of said pumping chamber and a compression stroke of said pumping plunger decreases volume of said pumping chamber;
• and
• a combination outlet valve and pressure relief valve for controlling outlet fuel flow of said fuel pump and for relieving over-pressurization downstream of said fuel pump, said combination outlet valve and pressure relief comprising:
• an outer housing having an outer housing passage extending therethrough from an outer housing inlet to an outer housing outlet;
• an inner housing located within said outer housing passage and extending along an inner housing axis from an inner housing first end face to an inner housing second end face, said inner housing having an outlet valve bore extending thereinto from said inner housing first end face and also having a pressure relief valve bore extending thereinto from said inner housing second end face such that said outlet valve bore and said pressure relief valve bore terminate at an inner housing wall which is traverse to said inner housing axis;
• an outlet valve assembly comprising an outlet valve member located within said outlet valve bore, an outlet valve seat located within said outlet valve bore, and an outlet valve spring located within said outlet valve bore, said outlet valve member being moveable between 1) a seated position which prevents fluid communication between said outer housing inlet and said outer housing outlet through said outlet valve bore by way of said outlet valve seat and 2) an unseated position which permits fluid communication between said outer housing inlet and said outer housing outlet through said outlet valve bore by way of said outlet valve seat, said outlet valve spring being grounded to said inner housing wall and biasing said outlet valve member toward said seated position;
• and
• a pressure relief valve assembly and comprising a pressure relief valve member located within said pressure valve bore, a pressure relief valve seat located within said pressure relief valve bore, and a pressure relief valve spring located within said outlet valve bore, said pressure relief valve member being moveable between 1) a seated position which prevents fluid communication between said outer housing outlet and said outer housing inlet through said pressure relief valve bore by way of said pressure relief valve seat and 2) an unseated position which permits fluid communication between said outer housing outlet and said outer housing inlet through said pressure relief valve bore by way of said pressure relief valve seat, said pressure relief valve spring being grounded to said inner housing wall and biasing said pressure relief valve member toward said seated position.