Internal combustion engine with variable compression ratio

• US 20060070605A1
• Filed: 11/04/2005
• Published: 04/06/2006
• Est. Priority Date: 01/21/2004
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kamiyama, Eiichi, Akihisa, Daisuke, Kikori, Shigeo, Kikori, Akio
• Granted Patent: US 7,422,004 B2
• Time in Patent Office: Days
• US Class Current: 123/478
• CPC Class Codes: F02B 75/041 by means of cylinder or cylinderhead positioning
• CPC Class Codes: F02D 13/0203 Variable control of intake and exhaust valves
• CPC Class Codes: F02D 13/0234 changing the valve timing only
• CPC Class Codes: F02D 13/0253 Fully variable control of valve lift and timing using camless actuation systems such as hydraulic, pneumatic or electromagnetic actuators, e.g. solenoid valves
• CPC Class Codes: F02D 13/0261 Controlling the valve overlap
• CPC Class Codes: F02D 15/04 by alteration of volume of compression space without changing piston stroke
• CPC Class Codes: F02D 2200/0411 Volumetric efficiency
• CPC Class Codes: F02D 2200/0614 Actual fuel mass or fuel injection amount
• CPC Class Codes: F02D 41/006 using internal EGR control of valve overlap for internal EGR F02D13/0261; arrangements for internal EGR F02M26/01
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/04 Introducing corrections for particular operating conditions F02D41/14 takes precedence
• CPC Class Codes: F02D 41/14 Introducing closed-loop corrections
• CPC Class Codes: F02D 41/187 using a hot wire flow sensor
• CPC Class Codes: F02M 26/01 Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages
• CPC Class Codes: F02M 26/13 Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In a variable compression ratio internal combustion engine in which the compression ratio is changed by changing the combustion chamber volume, the present invention enables to inhibit irregularities in the air-fuel ratio involved by changing of the combustion chamber volume. In a transition period during which the compression ratio is changed, the actual volume of the combustion chamber realized by a compression ratio changing mechanism is detected. A factor that influences the air-fuel ratio (for example, fuel injection quantity, cylinder intake air quantity or amount of EGR) is controlled based on the actual volume of the combustion chamber thus detected to make the air-fuel ratio substantially equal to that before and after the change of the compression ratio.

Claims

1. An internal combustion engine with a variable compression ratio comprising:

exhaust gas purifying catalyst provided in an exhaust passage

compression ratio changing mechanism for changing the compression ratio by changing the volume of a combustion chamber; and

,

control unit for controlling a factor that influences the air-fuel ratio in such a way that in a transition period during which the compression ratio is changed, the air-fuel ratio of air-fuel mixture in a cylinder becomes substantially equal to the air-fuel ratio before and after the change of the compression ratio.

2. An internal combustion engine with a variable compression ratio according to claim 1, wherein said control unit corrects a fuel injection quantity in such a way that in a transition period during which the compression ratio is changed, the air-fuel ratio of air-fuel mixture in the cylinder becomes substantially equal to the air-fuel ratio before and after the change of the compression ratio.

3. An internal combustion engine with a variable compression ratio according to claim 2, wherein in the transition period during which the compression ratio is changed to a high compression ratio, correction to make the fuel injection quantity smaller than that in the period during which the compression ratio is kept constant is performed.

4. An internal combustion engine with a variable compression ratio according to claim 3, wherein the cylinder in which the fuel injection quantity is corrected is a cylinder that is on the intake stroke in the transition period during which the compression ratio is changed to a high compression ratio.

5. An internal combustion engine with a variable compression ratio according to claim 2, wherein in a transition period during which the compression ratio is changed to a low compression ratio, correction to make the fuel injection quantity larger than that in the period during which the compression ratio is kept constant is performed.

6. An internal combustion engine with a variable compression ratio according to claim 5, wherein the cylinder in which the fuel injection quantity is corrected is a cylinder that is on the intake stroke in the transition period during which the compression ratio is changed to a low compression ratio.

7. An internal combustion engine with a variable compression ratio according to claim 1, wherein in the transition period during which the compression ratio is changed, said control unit detects an actual volume of the combustion chamber, and controls the factor that influences the air-fuel ratio based on the actual volume of the combustion chamber thus detected.

8. An internal combustion engine with a variable compression ratio according to claim 7, wherein in the transition period during which the compression ratio is changed, said control unit controls a fuel injection quantity based on the actual volume of the combustion chamber.

9. An internal combustion engine with a variable compression ratio according to claim 7 further comprising a variable valve actuation mechanism for varying a valve opening characteristic of an intake valve and/or an exhaust valve, wherein in the transition period during which the compression ratio is changed, said control unit controls the variable valve actuation mechanism based on the actual volume of the combustion chamber.

10. An internal combustion engine with a variable compression ratio according to claim 7 further comprising an EGR mechanism for changing an amount of EGR in the internal combustion engine, wherein in the transition period during which the compression ratio is changed, said control unit controls the EGR mechanism based on the actual volume of the combustion chamber.

11. An internal combustion engine with a variable compression ratio according to claims 7, wherein the cylinder in which the factor that influences the air-fuel ratio is controlled based on the actual volume of the combustion chamber is a cylinder that is on the exhaust stroke in the transition period during which the compression ratio is changed.

12. An internal combustion engine with a variable compression ratio according to claims 8, wherein the cylinder in which the factor that influences the air-fuel ratio is controlled based on the actual volume of the combustion chamber is a cylinder that is on the exhaust stroke in the transition period during which the compression ratio is changed.

13. An internal combustion engine with a variable compression ratio according to claims 9, wherein the cylinder in which the factor that influences the air-fuel ratio is controlled based on the actual volume of the combustion chamber is a cylinder that is on the exhaust stroke in the transition period during which the compression ratio is changed.

14. An internal combustion engine with a variable compression ratio according to claims 10, wherein the cylinder in which the factor that influences the air-fuel ratio is controlled based on the actual volume of the combustion chamber is a cylinder that is on the exhaust stroke in the transition period during which the compression ratio is changed.

15. A control apparatus for an internal combustion engine with a variable compression ratio comprising:

a compression ratio changing mechanism for changing the compression ratio by changing the volume of a combustion chamber;

combustion chamber volume detection apparatus for detecting the actual volume of the combustion chamber realized by said compression ratio changing mechanism; and

control unit for controlling a factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus.

16. A control apparatus of an internal combustion engine with a variable compression ratio according to claim 15, wherein said control unit controls a fuel injection quantity based on said actual volume of the combustion chamber.

17. A control apparatus of an internal combustion engine with a variable compression ratio according to claim 16, wherein said control unit controls the fuel injection quantity in such a way that the air-fuel ratio of air-fuel mixture becomes equal to a target air-fuel ratio.

18. An internal combustion engine with a variable compression ratio according to claim 15, wherein said control unit controls an intake air quantity of a cylinder based on said actual volume of the combustion chamber.

19. A control apparatus of an internal combustion engine with a variable compression ratio according to claim 18, wherein said control unit controls the intake air quantity of the cylinder in such a way that the air-fuel ratio of air-fuel mixture becomes equal to a target air-fuel ratio.

20. A control apparatus of an internal combustion engine with a variable compression ratio according to claim 19 further comprising a variable valve actuation mechanism for changing a valve opening characteristic of an intake valve and/or an exhaust valve, wherein said control unit determines a target cylinder intake air quantity corresponding to a operating state of said internal combustion engine and controls an operation of said variable valve actuation mechanism based on said target cylinder intake air quantity and said actual volume of the combustion chamber.

21. A control apparatus of an internal combustion engine with a variable compression ratio according to claim 19 further comprising EGR mechanism for changing an amount of EGR, wherein said control unit determines a target amount of EGR corresponding to a operating state of said internal combustion engine and controls an operation of said EGR mechanism based on said target amount of EGR and said actual volume of the combustion chamber.

22. A control apparatus of an internal combustion engine with a variable compression ratio according to claims 15, wherein said control unit controls the factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus while the compression ratio is changed by said compression ratio changing mechanism.

23. A control apparatus of an internal combustion engine with a variable compression ratio according to claims 17, wherein said control unit controls the factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus while the compression ratio is changed by said compression ratio changing mechanism.

24. A control apparatus of an internal combustion engine with a variable compression ratio according to claims 19, wherein said control unit controls the factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus while the compression ratio is changed by said compression ratio changing mechanism.

25. A control apparatus of an internal combustion engine with a variable compression ratio according to claims 20, wherein said control unit controls the factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus while the compression ratio is changed by said compression ratio changing mechanism.

26. A control apparatus of an internal combustion engine with a variable compression ratio according to claims 21, wherein said control unit controls the factor that influences the air-fuel ratio based on said actual volume of the combustion chamber detected by said combustion chamber volume detection apparatus while the compression ratio is changed by said compression ratio changing mechanism.