Method and system for supplying fuel gas

1. A system for introducing a gaseous fuel to an internal combustion engine, the system comprising:

a fuel storage device;

a compressor; and

an air and fuel conduit in fluid communication with the fuel storage device and with the compressor, the air and fuel conduit including:

a first passage; and

a second passage that includes a first portion and a second portion, the second portion being a venturi portion that includes an inlet opening configured to receive fuel, the venturi portion being configured to receive an entirety of the air that passes through the second passage, the inlet opening being provided on an inner surface of the second passage, the second passage being fluidly connected to the compressor in parallel with the first passage wherein the air and fuel conduit is connected upstream of the compressor.

2. The system of claim 1 , wherein the fuel storage device is configured to supply gaseous fuel to the first passage and to the second passage.

3. The system of claim 2 , wherein the first passage includes an additional inlet opening configured to receive the gaseous fuel.

4. The system of claim 1 , wherein the first passage includes a valve configured to selectively permit and prohibit a flow of air and fuel through the first passage.

5. The system of claim 4 , further comprising an actuator configured to change a position of the valve in response to a change in a pressure of gas compressed by the compressor.

6. The system of claim 1 , further comprising a mixing passage connected between the air and fuel conduit and the compressor.

7. The system of claim 1 , further comprising a storage device storing natural gas, the storage device being in fluid communication with the air and fuel conduit.

8. A fuel system, comprising:

a fuel storage device;

a first passage including:

a first air inlet configured to receive intake air;

a first fuel inlet in fluid communication with the fuel storage device and configured to receive gaseous fuel downstream of the first air inlet; and

a valve configured to open and close the first passage; and

an actuator configured to change a position of the valve in response to a change in a pressure of gas compressed by a compressor;

a second passage connected in parallel with the first passage, the first passage and the second passage being upstream of the compressor, the second passage including:

a second air inlet configured to receive intake air; and

a second fuel inlet configured to receive gaseous fuel downstream of the second air inlet.

9. The fuel system of claim 8 , wherein the actuator is configured to cause the valve to open, from a closed position, when a pressure of gas output from the compressor is at least a minimum opening pressure.

10. The fuel system of claim 9 , wherein the actuator is a pneumatic actuator.

11. The fuel system of claim 9 , wherein the second passage is permanently open to a flow of air.

12. The fuel system of claim 9 , wherein the valve is configured to fully open when the pressure of gas output from the compressor is at least the minimum opening pressure.

13. The fuel system of claim 8 , wherein the valve is disposed downstream of the first air inlet and downstream of the first fuel inlet.

14. A method for supplying fuel and air to an internal combustion engine, the method comprising:

controlling a flow of intake air and fuel through a first passage of an air and fuel conduit;

receiving intake air and fuel with a second passage of the air and fuel conduit, the second passage being connected in parallel with the first passage;

opening the first passage when a pressure of gas from a compressor downstream of the first passage and the second passage of the air and fuel conduit reaches an opening pressure to permit a flow of the intake air and fuel; and

supplying the intake air and fuel from the first passage and from the second passage to the internal combustion engine.

15. The method of claim 14 , wherein controlling the flow of intake air and fuel through the first passage includes blocking the flow of the intake air and fuel through the first passage with a valve positioned within the first passage.

16. The method of claim 14 , wherein the fuel is supplied as a gaseous fuel.

17. The method of claim 16 , wherein the gaseous fuel includes natural gas.

18. The system of claim 1 , wherein the inlet opening is disposed at a narrowest portion of the venturi portion.

19. The system of claim 1 , wherein the first passage has a substantially constant diameter.