Fuel system for an LPG engine

1. A fuel system for an internal combustion engine operated with fuel gas, comprising:

an evaporator in which fuel gas stored in a liquid state is transformed by the application of heat into a gaseous state, the evaporator comprising:

a first heating device for the fuel gas, the first heating device configured to transmit a portion of the waste heat of an internal combustion engine to the fuel gas in the evaporator; and

a second heating device by means of which the fuel gas in the evaporator can be heated regardless of the condition of the internal combustion engine, wherein the second heating device partitions the evaporator into a first evaporator chamber and a second evaporator chamber.

2. The fuel system as claimed in claim 1 , wherein the second heating device includes an electrical heating element.

3. The fuel system as claimed in claim 2 , wherein the electrical heating element of the second heating device is a PTC heating element.

4. The fuel system as claimed in claim 1 , wherein the first evaporator chamber and second evaporator chamber are connected to each other by a valve.

5. The fuel system as claimed in claim 1 , wherein the first heating device is located inside the evaporator.

6. The fuel system as claimed in claim 4 , wherein the first heating device is located so that the fuel gas in the first evaporator chamber and the fuel gas in the second evaporator chamber are heated by the first heating device.

7. The fuel system as claimed in claim 1 , wherein the second heating device is located inside the evaporator.

8. The fuel system as claimed in claim 4 , wherein the second heating device is located so that the fuel gas in the first evaporator chamber and the fuel gas in the second evaporator chamber are heated by the second heating device.

9. The fuel system as claimed in claim 1 , wherein the second heating device is located so that a liquid medium located in the first heating device is heated by the second heating device.

10. A fuel system for an internal combustion engine operated with fuel gas, comprising:

an evaporator in which fuel gas stored in a liquid state is transformed by the application of heat into a gaseous state, the evaporator comprising:

a first heating device for the fuel gas, the first heating device configured to transmit a portion of the waste heat of an internal combustion engine to the fuel gas in the evaporator; and

a second heating device by means of which the fuel gas in the evaporator can be heated regardless of the condition of the internal combustion engine,

wherein the evaporator includes a first evaporator chamber and a second evaporator chamber connected to each other by a valve, and

wherein the second heating device forms a partition between the first evaporator chamber and the second evaporator chamber.

11. The fuel system as claimed in claim 1 , including an evaporator inlet and a magnetically actuated shutoff valve positioned in the vicinity of the evaporator inlet through which the fuel gas enters the evaporator in the liquid state.

12. The fuel system as claimed in claim 1 , including an evaporator outlet through which the fuel gas in the gaseous state exits the evaporator, wherein the outlet is connected with a common rail located on the internal combustion engine.

13. A fuel system for an internal combustion engine operated with fuel gas, comprising:

a common rail located on an internal combustion engine;

an evaporator in which fuel gas stored in a liquid state is transformed by the application of heat into a gaseous state, the evaporator comprising:

a first heating device for the fuel gas, the first heating device configured to transmit a portion of the waste heat of an internal combustion engine to the fuel gas in the evaporator;

a second heating device by means of which the fuel gas in the evaporator can be heated regardless of the condition of the internal combustion engine; and

an evaporator outlet through which the fuel gas in the gaseous state exits the evaporator, wherein the outlet is connected with the common rail located on the internal combustion engine; and

a third heating device located on the common rail.

14. The fuel system as claimed in claim 13 , wherein the third heating device includes an electrical heating element.

15. The fuel system as claimed in claim 14 , wherein the electrical heating element of the third heating device is a PTC heating element.

16. A fuel system, comprising:

an internal combustion engine;

a source of liquid fuel gas; and

an evaporator in flow communication with the liquid fuel gas, the evaporator comprising:

a first chamber and a second chamber;

a first heating element configured to transmit waste heat from the internal combustion engine into at least one of the first and second evaporator chambers; and

a second heating device configured to provide heat to at least one of the first and second evaporator chambers, the second heating device comprising an electrical heating element,

wherein the second heating device forms a partition between the first and second evaporator chambers.

17. The fuel system as claimed in claim 16 , wherein the first and second heating devices are located inside the evaporator.

18. A fuel system, comprising:

an internal combustion engine;

a source of liquid fuel gas; and

an evaporator in flow communication with the liquid fuel gas, the evaporator comprising:

a first chamber and a second chamber;

a first heating chamber element configured to transmit waste heat from the internal combustion engine into at least one of the first and second evaporator chambers; and

a second heating device configured to provide heat to at least one of the first and second evaporator chambers, the second heating device comprising an electrical heating element,

wherein the fuel system further includes a common rail connected to the evaporator and a third heating device configured to transmit heat to the common rail.

19. The fuel system as claimed in claim 18 , wherein the third heating device includes an electrical heating element.