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1. WO2007004379 - FUEL SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

CLAIMS

1. A control device of a fuel system of an internal combustion engine including a low-pressure pump supplying fuel from a fuel tank to a fuel injection mechanism and a high-pressure pump provided between said low-pressure pump and said fuel injection mechanism and increasing pressure of the supplied fuel, comprising:
a detection portion detecting that an operation state of said internal combustion engine is an idle operation state;
a fuel state detection portion detecting a state of fuel in a pipe connecting said high-pressure pump and said fuel injection mechanism; and
a control portion controlling said low-pressure pump and said high-pressure pump,
said control portion controlling said high-pressure pump and said low-pressure pump such that, when said idle operation state is detected, pressure of the fuel discharged from said high-pressure pump and pressure of the fuel discharged from said low-pressure pump are adjusted based on the state of the fuel in said pipe.

2. The control device of a fuel system of an internal combustion engine according to claim 1, wherein said fuel state detection portion detects a state of vaporization of the fuel in said pipe.

3. The control device of a fuel system of an internal combustion engine according to claim 2, wherein said fuel state detection portion detects said state of vaporization based on at least one of a temperature of said internal combustion engine, a temperature of the fuel in said pipe, an engine speed of said internal combustion engine, and a load of said internal combustion engine.

4. The control device of a fuel system of an internal combustion engine according to claim 2, wherein said fuel state detection portion detects said state of vaporization based on a continuation time of the operation state determined by at least one of a temperature of said internal combustion engine, a temperature of the fuel in said pipe, an engine speed of said internal combustion engine, and a load of said internal combustion engine.

5. The control device of a fuel system of an internal combustion engine according to claim 1, wherein said control portion controls said high-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is large, the pressure of the fuel discharged from said high-pressure pump is increased.

6. The control device of a fuel system of an internal combustion engine according to claim 1, wherein said control portion controls said high-pressure pump and said low-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is small, an increase of the pressure of the fuel discharged from said high-pressure pump is stopped and the pressure of the fuel discharged from said low-pressure pump is adjusted in accordance with said degree of vaporization.

7. The control device of a fuel system of an internal combustion engine according to claim 6, wherein said control portion controls said low-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is small, the pressure of the fuel discharged from said low-pressure pump is increased when said degree of vaporization is higher than when said degree of vaporization is lower.

8. The control device of a fuel system of an internal combustion engine according to claim 1, wherein
a low-pressure fuel pipe system including said low-pressure pump is formed in said fuel system, and said low-pressure fuel pipe system is configured to allow adjustment of the pressure of the fuel in the pipe.

9. The control device of a fuel system of an internal combustion engine according to claim 8, wherein
said low-pressure pump is a pump having a discharge amount controllable, and said control portion adjusts the pressure of the fuel in the pipe in said low-pressure fuel pipe system by a mechanism that changes pressure depending on a flow rate.

10. The control device of a fuel system of an internal combustion engine according to claim 9, wherein said mechanism is a pressure regulator that increases the pressure with an increase of the flow rate.

11. The control device of a fuel system of an internal combustion engine according to claim 8, wherein said control portion adjusts the pressure of the fuel in the pipe in said low-pressure fuel pipe system by a variable pressure regulator.

12. The control device of a fuel system of an internal combustion engine according to any of claims 1-11, wherein
said fuel injection mechanism is a first fuel injection mechanism injecting fuel into a cylinder, and
said internal combustion engine further includes a second fuel injection mechanism injecting fuel into an intake manifold.

13. The control device of a fuel system of an internal combustion engine according to claim 12, wherein
said first fuel injection mechanism is an in-cylinder injector, and said second fuel injection mechanism is an intake manifold injector.

14. A control device of a fuel system of an internal combustion engine including a low-pressure pump supplying fuel from a fuel tank to a fuel injection mechanism and a high-pressure pump provided between said low-pressure pump and said fuel injection mechanism and increasing pressure of the supplied fuel, comprising: detection means for detecting that an operation state of said internal combustion engine is an idle operation state;
fuel state detection means for detecting a state of fuel in a pipe connecting said high-pressure pump and said fuel injection mechanism; and
control means for controlling said low-pressure pump and said high-pressure pump,
said control means including means for controlling said high-pressure pump and said low-pressure pump such that, when said idle operation state is detected, pressure of the fuel discharged from said high-pressure pump and pressure of the fuel discharged from said low-pressure pump are adjusted based on the state of the fuel in said pipe.

15. The control device of a fuel system of an internal combustion engine according to claim 14, wherein said fuel state detection means includes means for detecting a state of vaporization of the fuel in said pipe.

16. The control device of a fuel system of an internal combustion engine according to claim 15, wherein said fuel state detection means includes means for detecting said state of vaporization based on at least one of a temperature of said internal combustion engine, a temperature of the fuel in said pipe, an engine speed of said internal combustion engine, and a load of said internal combustion engine.

17. The control device of a fuel system of an internal combustion engine according to claim 15, wherein said fuel state detection means includes means for detecting said state of vaporization based on a continuation time of the operation state determined by at least- one of a temperature of said internal combustion engine, a temperature of the fuel in said pipe, an engine speed of said internal combustion engine, and a load of said internal combustion engine.

18. The control device of a fuel system of an internal combustion engine according to claim 14, wherein said control means includes means for controlling said high-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is large, the pressure of the fuel discharged from said high-pressure pump is increased.

19. The control device of a fuel system of an internal combustion engine according to claim 14, wherein said control means includes means for controlling said high-pressure pump and said low-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is small, an increase of the pressure of the fuel discharged from said high-pressure pump is stopped and the pressure of the fuel discharged from said low-pressure pump is adjusted in accordance with said degree of vaporization.

20. The control device of a fuel system of an internal combustion engine according to claim 19, wherein said control means includes means for controlling said low-pressure pump such that, in the state where the degree of vaporization of the fuel in said pipe is small, the pressure of the fuel discharged from said low-pressure pump is increased when said degree of vaporization is higher than when said degree of vaporization is lower.

21. The control device of a fuel system of an internal combustion engine according to claim 14, wherein
a low-pressure fuel pipe system including said low-pressure pump is formed in said fuel system, and
said low-pressure fuel pipe system is configured to allow adjustment of the pressure of the fuel in the pipe.

22. The control device of a fuel system of an internal combustion engine according to claim 21, wherein
said low-pressure pump is a pump having a discharge amount controllable, and said control means adjusts the pressure of the fuel in the pipe in said low-pressure fuel pipe system by a mechanism that changes pressure depending on a flow rate.

i" 23. The control device of a fuel system of an internal combustion engine according to claim 22, wherein said mechanism is a pressure regulator that increases the pressure with an increase of the flow rate.

24. The control device of a fuel system of an internal combustion engine according to claim 21, wherein said control means adjusts the pressure of the fuel in the pipe in said low-pressure fuel pipe system by a variable pressure regulator.

25. The control device of a fuel system of an internal combustion engine according to any of claims 14-24, wherein
said fuel injection mechanism is a first fuel injection mechanism injecting fuel into a cylinder, and
said internal combustion engine further includes a second fuel injection mechanism injecting fuel into an intake manifold.

26. The control device of a fuel system of an internal combustion engine according to claim 25, wherein
said first fuel injection mechanism is an in-cylinder injector, and
said second fuel injection mechanism is an intake manifold injector.

27. A control device of a fuel system of an internal combustion engine including a low-pressure pump supplying fuel from a fuel tank to a fuel injection mechanism and a high-pressure pump provided between said low-pressure pump and said fuel injection mechanism and increasing pressure of the supplied fuel,
said control device comprising an electronic control unit (ECU),
said electronic control unit (ECU)
detecting that an operation state of said internal combustion engine is an idle operation state,
detecting a state of fuel in a pipe connecting said high-pressure pump and said fuel injection mechanism, and
controlling said high-pressure pump and said low-pressure pump such that, when said idle operation state is detected, pressure of the fuel discharged from said high-pressure pump and pressure of the fuel discharged from said low-pressure pump are adjusted based on the state of the fuel in said pipe.