Propulsion systems and modules for vehicles

1. A module for a propulsion system of a vehicle having a fuel tank, the propulsion system having an engine, the module comprising:

a retainer housing disposed within the fuel tank;

a fuel pump mounted on the retainer housing and configured to supply fuel flow having a pressure;

a check valve mounted on the retainer housing and configured to receive the fuel flow from the fuel pump and to allow passage of the fuel flow toward the engine; and

a relief valve mounted on the retainer housing, coupled to the fuel pump, and configured to release a portion of the pressure of the fuel flow, the relief valve disposed upstream of the check valve.

2. The module of claim 1 , further comprising:

a fuel filter coupled to the check valve and configured to filter the fuel flow between the check valve and the engine.

3. The module of claim 1 , wherein the relief valve is connected between the fuel pump and the check valve and is not part of the fuel pump.

4. The module of claim 1 , further comprising:

a strainer mounted on the retainer housing and coupled to the fuel pump.

5. The module of claim 1 , wherein the retainer housing comprises a molded plastic.

6. The module of claim 1 , wherein the relief valve comprises:

a valve body;

an inlet formed within the valve body;

a plurality of outlets formed circumferentially around a center of the valve body; and

a spring-loaded valve element disposed within the valve body and configured to control fluid flow from the inlet to the plurality of outlets.

7. A propulsion system for a vehicle having a diesel fuel tank, the propulsion system comprising:

a retainer housing disposed within the diesel fuel tank;

a diesel fuel combustion engine;

a fuel pump mounted on the retainer housing and configured to supply fuel flow having a pressure;

a check valve mounted on the retainer housing and configured to receive the fuel flow from the fuel pump and to allow passage of the fuel flow to the diesel fuel combustion engine; and

a relief valve mounted on the retainer housing, coupled to the fuel pump, and configured to release a portion of the pressure of the fuel flow, the relief valve disposed upstream of the check valve.

8. The propulsion system of claim 7 , further comprising:

a fuel filter coupled between the check valve and the engine and configured to filter the fuel flow between the check valve and the diesel fuel combustion engine.

9. The propulsion system of claim 7 , wherein the relief valve is connected between the fuel pump and the check valve and is not part of the fuel pump.

10. The propulsion system of claim 7 , further comprising:

a strainer mounted on the retainer housing and coupled to the fuel pump.

11. The propulsion system of claim 7 , wherein the retainer housing comprises a molded plastic.

12. The propulsion system of claim 7 , wherein the relief valve comprises:

a valve body;

an inlet formed within the valve body;

a plurality of outlets formed circumferentially around a center of the valve body; and

a spring-loaded valve element disposed within the valve body and configured to control fluid flow from the inlet to the plurality of outlets.

13. The propulsion system of claim 7 , wherein the propulsion system comprises one relief valve for the propulsion system, namely a single relief valve, and the single relief valve is configured to provide pressure relief for the propulsion system both upstream and downstream of the check valve.

14. A vehicle comprising:

a fuel tank;

a drive system; and

a propulsion system coupled to the drive system, the propulsion system comprising:

an engine;

a retainer housing disposed within the fuel tank;

a fuel pump mounted on the retainer housing and configured to supply fuel flow having a pressure;

a check valve mounted on the retainer housing and configured to receive the fuel flow from the fuel pump and to allow passage of the fuel flow to the engine; and

a single relief valve for the propulsion system, the single relief valve mounted on the retainer housing, coupled to the fuel pump, and configured to release a portion of the pressure of the fuel flow, the single relief valve disposed upstream of the check valve, the single relief valve configured to provide pressure relief for the propulsion system both upstream and downstream of the check valve.

15. The vehicle of claim 14 , wherein the engine comprises a diesel fuel combustion engine.

16. The vehicle of claim 14 , wherein the propulsion system further comprises:

a fuel filter coupled between the check valve and the engine and configured to filter the fuel flow between the check valve and the engine; and

a reservoir having a first wall and disposed within the fuel tank;

wherein:

the retainer is surrounded by the first wall of the reservoir;

the fuel tank has a second wall that surrounds the first wall of the reservoir; and

the fuel filter is disposed outside the fuel tank.

17. The vehicle of claim 14 , wherein the single relief valve is connected between the fuel pump and the check valve and is not part of the fuel pump.

18. The vehicle of claim 14 , wherein the propulsion system further comprises:

a strainer mounted on the retainer housing and coupled to the fuel pump.

19. The vehicle of claim 14 , wherein the retainer housing comprises a molded plastic.

20. The vehicle of claim 14 , wherein the single relief valve comprises:

a valve body;

an inlet formed within the valve body;

a plurality of outlets formed circumferentially around a center of the valve body; and

a spring-loaded valve element disposed within the valve body and configured to control fluid flow from the inlet to the plurality of outlets.