Fuel injector for internal combustion engine

• US 7,013,872 B2
• Filed: 11/05/2004
• Issued: 03/21/2006
• Est. Priority Date: 11/11/2003
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sakai, Mitsuto, Kurata, Naoki, Akita, Tatsuhiko, Yamazaki, Daichi
• Primary Examiner(s): Gimie, Mahmoud
• Application Number:
  US10/981,510
• Publication Number:
  US 20050098155A1
• Time in Patent Office: 501 Days
• Field of Search: 123/431, 123/510, 123/299, 123/300, 123/446
• US Class Current: 123/431
• CPC Class Codes: F02B 2075/125 Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• CPC Class Codes: F02D 2041/3881 with multiple common rails, e.g. one rail per cylinder bank, or a high pressure rail and a low pressure rail
• CPC Class Codes: F02D 41/3094 the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
• CPC Class Codes: F02D 41/3836 Controlling the fuel pressure
• CPC Class Codes: F02D 41/3854 with elements in the low pressure part, e.g. low pressure pump
• CPC Class Codes: F02M 39/02 Arrangements of fuel-injection apparatus to facilitate the driving of pumps; Arrangements of fuel-injection pumps; Pump drives
• CPC Class Codes: F02M 59/102 Mechanical drive, e.g. tappets or cams F02M45/063 takes precedence
• CPC Class Codes: F02M 59/30 with variable-length-stroke pistons swash-plate type pumps F02M59/04
• CPC Class Codes: F02M 59/366 Valves being actuated electrically
• CPC Class Codes: F02M 59/44 Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
• CPC Class Codes: F02M 63/02 Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
• CPC Class Codes: F02M 63/021 by locking pump pistons
• CPC Class Codes: F02M 63/0225 Fuel-injection apparatus having a common rail feeding several injectors F02M63/0003 takes precedence; Means for varying pressure in common rails; Pumps feeding common rails
• CPC Class Codes: F02M 63/025 from the common rail
• CPC Class Codes: F02M 63/0285 having more than one common rail
• CPC Class Codes: F02M 69/462 Arrangement of fuel conduits, e.g. with valves for maintaining pressure in the pipes after the engine being shut-down
• CPC Class Codes: F02M 69/465 of fuel rails
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A fuel injector for an internal combustion engine including an in-cylinder fuel injection valve and an intake port fuel injection valve. An ECU controls an electromagnetic valve to keep a fuel inlet of a high pressure pump closed during an intake port injection mode during which fuel is injected only from an intake port fuel injection valve. As a result, even if the plunger reciprocates in the high pressure pump, fuel does not flow between the high pressure pump and a low pressure fuel path. Thus, pressure pulsation that would be caused by the operation of the high pressure pump does not occur in low pressure fuel.

Claims

1. A fuel injector for an internal combustion engine including a cylinder and an intake port communicated with the cylinder, the fuel injector comprising:

an intake port fuel injection valve for injecting fuel into the intake port;

an in-cylinder fuel injection valve for directly injecting fuel into a combustion chamber of the cylinder;

a low pressure fuel path for supplying the intake port fuel injection valve with fuel having relatively low pressure;

a pump for pressurizing the fuel having relatively low pressure to supply the in-cylinder fuel injection valve with fuel having relatively high pressure; and

a controller for controlling the intake port fuel injection valve and the in-cylinder fuel injection valve in accordance with an operating condition of the internal combustion engine,

wherein the controller includes a flow restricting means for restricting fuel flow between the pump and the low pressure fuel path during an intake port injection mode in which only the intake port fuel injection valve injects fuel.

2. The fuel injector according to claim 1, further comprising:

a low pressure fuel intake passage for connecting the pump and the low pressure fuel supply path;

wherein the flow restricting means includes;

a shutting valve for selectively closing the low pressure fuel intake passage;

a shut controlling means for controlling the shutting valve, the shutting controlling means opening the shutting valve when the in-cylinder fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running, and the shutting controlling means closing the shutting valve in the intake port injection mode.

3. The fuel injector according to claim 1, wherein the pump includes an adjustment valve for adjusting the amount of the fuel having relatively low pressure that is drawn into the pump, and wherein the flow restricting means controls an open amount of the adjustment valve when the in-take fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running to adjust the amount of the relatively low pressure fuel that is pressurized by the pump and supplied to the in-cylinder fuel injection valve as the fuel having relatively high pressure, the ratio of time that the adjustment valve is open to when it is closed being decreased in the intake port injection mode.

4. The fuel injector according to claim 3, wherein the flow restricting means completely closes the adjustment valve in the intake port injection mode.

5. The fuel injector according to claim 1, wherein:

the pump includes a pressurizing chamber having a volume, and a pressurizing member for changing the volume of the pressurizing chamber when driven;

the pressurizing member changing the volume of the pressurizing member to draw the fuel having relatively low pressure into the pressurizing chamber, pressurize the fuel having relatively low pressure in the pressurizing chamber, and supply the in-cylinder fuel injection valve with the fuel having relatively high pressure that was pressurized; and

the flow restricting means suppressing change in the volume of the pressurizing chamber with the pressurizing member during the intake port injection mode.

6. The fuel injector according to claim 5, wherein the flow restricting means suppresses a drive amount of the pressurizing member during the intake port injection mode.

7. The fuel injector according to claim 6, wherein the flow restricting means stops driving the pressurizing member during the intake port injection mode.

8. A fuel injector for an internal combustion engine including a cylinder and an intake port communicated with the cylinder, the fuel injector comprising:

an intake port fuel injection valve for injecting fuel, into the intake port;

an in-cylinder fuel injection valve for directly injecting fuel into a combustion chamber of the cylinder;

a low pressure fuel path for supplying the intake port fuel injection valve with fuel having relatively low pressure;

a pump for pressurizing, the fuel having relatively low pressure to supply the in-cylinder fuel injection valve with fuel having relatively high pressure; and

a controller for controlling the intake port fuel injection valve and the in-cylinder fuel injection valve in accordance with an operating condition of the internal combustion engine,

wherein the controller executes a flow restricting process for restricting fuel flow between the pump and the low pressure fuel path during an intake port injection mode in which only the intake port fuel injection valve injects fuel.

9. The fuel injector according to claim 8, further comprising:

a low pressure fuel intake passage for connecting the pump and the low pressure fuel supply path; and

a shutting valve for selectively closing the low pressure fuel intake passage,

wherein the controller executes a shut controlling process for opening the shutting valve when the in-cylinder fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running, and for closing the shutting valve in the intake port injection mode.

10. The fuel injector according to claim 8, wherein the pump includes an adjustment valve for adjusting the amount of the fuel having relatively low pressure that is drawn into the pump, and wherein the controller controls an open amount of the adjustment valve when the in-take fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running to adjust the amount of the relatively low pressure fuel that is pressurized by the pump and supplied to the in-cylinder fuel injection valve as the fuel having relatively high pressure, the ratio of time that the adjustment valve is open to when it is closed being decreased in the intake port injection mode.

11. The fuel injector according to claim 10, wherein the controller completely closes the adjustment valve in the intake port injection mode.

12. The fuel injector according to claim 8, wherein:

the pump includes a pressurizing chamber having a volume, and a pressurizing member for changing the volume of the pressurizing chamber when driven;

the pressurizing member changing the volume of the pressurizing member to draw the fuel having relatively low pressure into the pressurizing chamber, pressurize the fuel having relatively low pressure in the pressurizing chamber, and supply the in-cylinder fuel injection valve with the fuel having relatively high pressure that was pressurized; and

the controller suppressing change in the volume of the pressurizing chamber with the pressurizing member during the intake port injection mode.

13. The fuel injector according to claim 12, wherein the controller suppresses a drive amount of the pressurizing member during the intake port injection mode.

14. The fuel injector according to claim 13, wherein the controller stops driving the pressurizing member during the intake port injection mode.

15. A method for supplying fuel to an internal combustion engine, wherein the internal combustion engine includes a cylinder, an intake port communicated with the cylinder, and a fuel injector, the fuel injector including:

an intake port fuel injection valve for injecting fuel into the intake port;

an in-cylinder fuel injection valve for directly injecting fuel into a combustion chamber of the cylinder;

a low pressure fuel path for supplying the intake port fuel injection valve with fuel having relatively low pressure; and

a pump for pressurizing the fuel having relatively low pressure to supply the in-cylinder fuel injection valve with fuel having relatively high pressure, the method comprising;

injecting fuel from at least one of the intake port fuel injection valve and the in-cylinder fuel injection valve; and

restricting fuel flow between the pump and the low pressure fuel path when only the intake port fuel injection valve injects fuel.

16. The method according to claim 15, wherein the internal combustion engine further includes a low pressure fuel intake passage for connecting the pump and the low pressure fuel supply path, and wherein said restricting fuel flow includes:

opening the low pressure fuel supply path when the in-cylinder fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running; and

closing the low pressure fuel supply path when only the intake port fuel injection valve injects fuel.

17. The method according to claim 15, wherein the pump includes an adjustment valve for adjusting the amount of the fuel having relatively low pressure that is drawn into the pump, and wherein said restricting fuel flow includes:

controlling an open amount of the adjustment valve when the in-take fuel injection valve is supplied with the fuel having relatively high pressure and the internal combustion engine is running to adjust the amount of the relatively low pressure fuel pressurized by the pump and supplied to the in-cylinder fuel injection valve as the fuel having relatively high pressure; and

decreasing the ratio of time that the adjustment valve is open to when it is closed when only the intake port fuel injection valve injects fuel.

18. The method according to claim 17, wherein said restricting fuel flow includes completely closing the adjustment valve when only the intake port fuel injection valve injects fuel.

19. The method according to claim 15, wherein:

the pump includes a pressurizing chamber having a volume, and a pressurizing member for changing the volume of the pressurizing chamber when driven, the pressurizing member changing the volume of the pressurizing member to draw the fuel having relatively low pressure into the pressurizing chamber, pressurize the fuel having relatively low pressure in the pressurizing chamber, and supply the in-cylinder fuel injection valve with the fuel having relatively high pressure that was pressurized; and

said restricting fuel flow includes suppressing change in the volume of the pressurizing chamber with the pressurizing member when only the intake port fuel injection valve injects fuel.

20. The method according to claim 19, wherein said restricting fuel flow includes suppressing a drive amount of the pressurizing member when only the intake port fuel injection valve injects fuel.

21. The method according to claim 20, wherein said restricting fuel flow includes stopping the driving of the pressurizing member when only the intake port fuel injection valve injects fuel.