Fuel pump and inlet valve assembly thereof

1. 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

an inlet valve assembly comprising:

a check valve member which is moveable between 1) an unseated position which provides fluid communication between said pumping chamber and a fuel supply passage and 2) a seated position which prevents fluid communication between said pumping chamber and said fuel supply passage; and

a solenoid assembly which includes a wire winding; a pole piece; an armature which is moveable along an inlet valve axis between 1) a first position when said wire winding is not energized with electricity and 2) a second position when said wire winding is energized with electricity; a return spring which biases said armature away from said pole piece; and a control rod which is moveable along said inlet valve axis independently of said armature, wherein said first position of said armature urges said control rod to hold said check valve member in said unseated position and wherein said second position of said armature allows said check valve member to move said control rod to allow said check valve member to move to said seated position.

2. A fuel pump as in claim 1 , wherein:

said armature includes an armature control rod bore; and

said control rod is received within said armature control rod bore such that said control rod is moveable along said inlet valve axis within said armature control rod bore.

3. A fuel pump as in claim 2 , wherein said control rod interfaces with said armature control rod bore in a close sliding interface.

4. A fuel pump as in claim 2 , where said control rod includes a control rod shoulder which limits the extent to which said control rod extends into said armature control rod bore.

5. A fuel pump as in claim 4 , wherein:

said control rod includes a control rod central portion and a control rod bushing such that said control rod bushing is fixed to said control rod in order to prevent relative movement between said control rod central portion and said control rod bushing;

said control rod bushing includes a control rod bushing bore;

said control rod central portion is received within said control rod bushing bore; and

said control rod shoulder is provided on said control rod bushing.

6. A fuel pump as in claim 5 , wherein:

said inlet valve assembly further comprises a valve body having a valve body end wall, said valve body end wall with a valve body central passage extending therethrough and a valve body outlet passage extending therethrough, said valve body outlet passage being blocked by said check valve member when said check valve member is in said seated position and said valve body outlet passage being unblocked by said check valve member when said check valve member is in said unseated position which allows fluid communication through said valve body outlet passage between said pumping chamber and said fuel supply passage; and

said control rod interfaces with said valve body central passage in a close sliding interface.

7. A fuel pump as in claim 6 , where:

said control rod shoulder is a first control rod shoulder; and

said control rod includes a control rod second shoulder which limits the extent to which said control rod extends into said valve body central passage.

8. A fuel pump as in claim 7 , wherein:

said control rod bushing is a first control rod bushing;

said control rod bushing bore is a first control rod bushing bore;

said control rod includes a control rod second bushing such that said control rod second bushing is fixed to said control rod in order to prevent relative movement between said control rod central portion and said control rod bushing;

said control rod second bushing includes a control rod second bushing bore;

said control rod central portion is received within said control rod second bushing bore; and

said control rod second shoulder is provided on said control rod second bushing.

9. A fuel pump as in claim 1 , wherein:

said inlet valve assembly further comprises a valve body having a valve body end wall, said valve body end wall with a valve body central passage extending therethrough and a valve body outlet passage extending therethrough, said valve body outlet passage being blocked by said check valve member when said check valve member is in said seated position and said valve body outlet passage being unblocked by said check valve member when said check valve member is in said unseated position which allows fluid communication through said valve body outlet passage between said pumping chamber and said fuel supply passage; and

said control rod interfaces with said valve body central passage in a close sliding interface.

10. A fuel pump as in claim 9 , where said control rod includes a control rod shoulder which limits the extent to which said control rod extends into said valve body central passage.

11. A fuel pump as in claim 10 , wherein:

said control rod includes a control rod central portion and a control rod bushing such that said control rod bushing is fixed to said control rod in order to prevent relative movement between said control rod central portion and said control rod bushing;

said control rod bushing includes a control rod bushing bore;

said control rod central portion is received within said control rod bushing bore; and

said control rod shoulder is provided on said control rod bushing.

12. An inlet valve assembly for a fuel pump having 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, said inlet valve assembly comprising:

a check valve member which is moveable between 1) an unseated position which provides fluid communication through said inlet valve assembly and 2) a seated position which prevents fluid communication through said inlet valve assembly; and

a solenoid assembly which includes a wire winding; a pole piece; an armature which is moveable along an inlet valve axis between 1) a first position when said wire winding is not energized with electricity and 2) a second position when said wire winding is energized with electricity; a return spring which biases said armature away from said pole piece; and a control rod which is moveable along said inlet valve axis independently of said armature, wherein said first position of said armature urges said control rod to hold said check valve member in said unseated position and wherein said second position of said armature allows said check valve member to move said control rod to allow said check valve member to move to said seated position.

13. An inlet valve assembly as in claim 12 , wherein:

said armature includes an armature control rod bore; and

said control rod is received within said armature control rod bore such that said control rod is moveable along said inlet valve axis within said armature control rod bore.

14. An inlet valve assembly as in claim 13 , wherein said control rod interfaces with said armature control rod bore in a close sliding interface.

15. An inlet valve assembly as in claim 13 , where said control rod includes a control rod shoulder which limits the extent to which said control rod extends into said armature control rod bore.

16. An inlet valve assembly as in claim 15 , wherein:

said control rod includes a control rod central portion and a control rod bushing such that said control rod bushing is fixed to said control rod in order to prevent relative movement between said control rod central portion and said control rod bushing;

said control rod bushing includes a control rod bushing bore;

said control rod central portion is received within said control rod bushing bore; and

said control rod shoulder is provided on said control rod bushing.

17. An inlet valve assembly as in claim 16 , wherein:

said inlet valve assembly further comprises a valve body having a valve body end wall, said valve body end wall with a valve body central passage extending therethrough and a valve body outlet passage extending therethrough, said valve body outlet passage being blocked by said check valve member when said check valve member is in said seated position and said valve body outlet passage being unblocked by said check valve member when said check valve member is in said unseated position which allows fluid communication through said valve body outlet passage between said pumping chamber and a fuel supply passage; and

said control rod interfaces with said valve body central passage in a close sliding interface.

18. An inlet valve assembly as in claim 17 , where:

said control rod shoulder is a first control rod shoulder; and

said control rod includes a control rod second shoulder which limits the extent to which said control rod extends into said valve body central passage.

19. An inlet valve assembly as in claim 18 , wherein:

said control rod bushing is a first control rod bushing;

said control rod bushing bore is a first control rod bushing bore;

said control rod includes a control rod second bushing such that said control rod second bushing is fixed to said control rod in order to prevent relative movement between said control rod central portion and said control rod bushing;

said control rod second bushing includes a control rod second bushing bore;

said control rod central portion is received within said control rod second bushing bore; and

said control rod second shoulder is provided on said control rod second bushing.