Method and Apparatus for Controlling an Internal Combustion Engine

• US 20090007564A1
• Filed: 06/19/2008
• Published: 01/08/2009
• Est. Priority Date: 06/26/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nemoto, Mamoru, SUZUKI, Kunihiko
• Granted Patent: US 7,918,090 B2
• Time in Patent Office: Days
• US Class Current: 60/602
• CPC Class Codes: F02B 29/0412 Multiple heat exchangers arranged in parallel or in series
• CPC Class Codes: F02B 37/013 with exhaust-driven pumps arranged in series
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02B 37/22 by varying cross-section of exhaust passages or air passages , e.g. by throttling turbine inlets or outlets or by varying effective number of guide conduits F02B37/24 takes precedence
• CPC Class Codes: F02B 37/24 by using pumps or turbines with adjustable guide vanes
• CPC Class Codes: F02D 13/0207 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 13/0219 by shifting the phase, i.e. the opening periods of the valves are constant
• CPC Class Codes: F02D 13/0269 Controlling the valves to perform a Miller-Atkinson cycle
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 23/00 Controlling engines characterised by their being supercharged
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A control device for an internal combustion engine, which comprise a turbocharger, of which turbo flow rate is made variable, and an intake valve provided with a variable valve mechanism and in which mirror cycle is performed, the control device comprising: device, which calculates an intake air quantity per unit time and an intake air quantity per cycle on the basis of torque required to the internal combustion engine; device, which controls the turbocharger so that with the intake air quantity per unit time, supercharging pressure is further increased in that range, in which a ratio of supercharging pressure and exhaust pressure is equal to or less than a predetermined value; and device, which controls the variable valve mechanism on the basis of the supercharging pressure and the intake air quantity per cycle.

Claims

1. A control device for an internal combustion engine, which comprise a turbocharger, of which turbo flow rate is made variable, and an intake valve provided with a variable valve mechanism and in which mirror cycle is performed,

the control device comprising:

means, which calculates an intake air quantity per unit time and an intake air quantity per cycle on the basis of torque required to the internal combustion engine;

means, which controls the turbocharger so that with the intake air quantity per unit time, supercharging pressure is further increased in that range, in which a ratio of supercharging pressure and exhaust pressure is equal to or less than a predetermined value; and

means, which controls the variable valve mechanism on the basis of the supercharging pressure and the intake air quantity per cycle.

2. The control device for an internal combustion engine, according to claim 1, wherein the turbocharger, of which flow rate is variable, is a variable turbocharger, in which a flap vane provided on an exhaust turbine inlet portion is operatively opened and closed to change a ratio of (A/R) of an area A of an exhaust turbine inlet nozzle and a distance R from an exhaust turbine inlet position to an axial center of an exhaust turbine, and the turbocharger comprises means, which controls A/R of the exhaust turbine so that with the intake air quantity per unit time, supercharging pressure is increased in that range, in which a ratio of supercharging pressure and exhaust pressure is equal to or less than a predetermined value.

3. The control device for an internal combustion engine, according to claim 1, wherein the turbocharger, of which flow rate is variable, comprises a multi-stage turbocharger, which comprises a plurality of turbochargers having different flow rate-supercharging pressure characteristics and in which waste-gate valves provided on the plurality of turbochargers are operatively opened and closed to select operating modes of the plurality of turbochargers, and the multi-stage turbocharger comprises means, which controls the waste-gate valves of the multi-stage turbocharger so that with the intake air quantity per unit time, supercharging pressure is increased in that range, in which a ratio of supercharging pressure and exhaust pressure is equal to or less than a predetermined value.

4. The control device for an internal combustion engine, according to claim 1, wherein the intake valve comprises a variable intake valve provided with a variable mechanism, which changes at least one of an opening and closing timing and lift of the valve continuously or stepwise, and the variable intake valve comprises means, which sets a closing timing of the variable intake valve to an advance side or a delay side with reference to a lower dead center in a state, in which an intake valve opening timing is substantially fixed to an upper dead center of the internal combustion engine, thereby decreasing the piston compression amount as compared with the piston compression expansion amount.

5. The control device for an internal combustion engine, according to claim 1, further comprising:

means, which calculates torque required to the internal combustion engine on the basis of an amount, by which a driver steps on an accelerator pedal;

means, which calculates a target intake air quantity per cycle of the internal combustion engine on the basis of the required torque; and

means, which controls an opening timing and an opened duration of the variable intake valve on the basis of the target intake air quantity per cycle, the supercharging pressure, and a rotating speed of the internal combustion engine.

6. The control device for an internal combustion engine, according to claim 1, further comprising means, which detects the exhaust pressure with an exhaust pressure sensor provided upstream of an exhaust turbine.

7. The control device for an internal combustion engine, according to claim 2, further comprising means, which deduces or calculates the exhaust pressure on the basis of the intake air quantity, the supercharging pressure, and A/R of the exhaust turbine.

8. The control device for an internal combustion engine, according to claim 3, further comprising means, which deduces or calculates the exhaust pressure on the basis of the intake air quantity, the supercharging pressure, and a state, in which the waste-gate valves of the multi-stage turbocharger are opened or closed.

9. The control device for an internal combustion engine, according to claim 1, further comprising:

either of means, which deduces a turbine rotating speed of the turbocharger on the basis of at least the intake air quantity and the supercharging pressure and means, which detects a turbine rotating speed;

means, which calculates an operation working point of the turbocharger on the basis of the intake air quantity, the supercharging pressure, and the turbine rotating speed; and

means, which controls the turbocharger, of which flow rate is variable, on the basis of the operation working point of the turbocharger.

10. The control device for an internal combustion engine, according to claim 5, further comprising means, which increases an opened duration of the variable intake valve on the basis of the required torque at the time of acceleration of the internal combustion engine, at which variation of an accelerator pedal stepping-on operation by a driver is equal to or more than a predetermined value, and thereafter increases A/R of the exhaust turbine on the variable turbocharger.

11. The control device for an internal combustion engine, according to claim 5, further comprising means, which increases an opened duration of the variable intake valve on the basis of the required torque at the time of acceleration of the internal combustion engine, at which variation of an accelerator pedal stepping-on operation by a driver is equal to or more than a predetermined value, and thereafter controls the waste-gate valves of the multi-stage turbocharger from a mode, in which the turbocharger or turbochargers on the small flow rate side in the flow rate-supercharging pressure characteristics operate, to a mode, in which the turbocharger or turbochargers on the large flow rate side operate.

12. The control device for an internal combustion engine, according to claim 4, further comprising means, which controls an ignition timing of the internal combustion engine to an advance side as a closing timing of the intake valve separates from a lower dead center, with the intake air quantity per unit time.

13. The control device for an internal combustion engine, according to claim 1, further comprising:

means, which connects a generator to a crank shaft of the internal combustion engine to cause the connected generator to generate electrical energy; and

means, which controls the internal combustion engine so that the charging efficiency of the internal combustion engine is held substantially in a high load condition of around 0.5 to 1.5.

14. The control device for an internal combustion engine, according to claim 1, further comprising means including a hybrid system composed of the internal combustion engine, a motor, and a generator, and controlling the internal combustion engine so that the charging efficiency of the internal combustion engine is held substantially in a high load condition of around 0.5 to 1.5.

15. A method of controlling an internal combustion engine comprising a turbocharger, of which turbo flow rate made variable, and an intake valve provided with a variable valve mechanism and in which mirror cycle is performed, the method comprising:

controlling the variable valve mechanism to increase an opened duration of the intake valve as torque required to the internal combustion engine increases stepwise; and

controlling the turbocharger to increase turbo flow rate and at the same time, controlling the variable valve mechanism to decrease an opened duration of the intake valve when torque of the internal combustion engine reaches the required torque.

16. The method of controlling an internal combustion engine, according to claim 15, wherein, the turbocharger is controlled so that a ratio (Pt/Pc) of exhaust pressure (Pt) and supercharging pressure (Pc) is made equal to or less than a predetermined value and supercharging pressure is further increased when torque of the internal combustion engine reaches the required torque.

17. The method of controlling an internal combustion engine, according to claim 16, wherein control is performed so that the supercharging pressure becomes maximum.

18. A control device for an internal combustion engine, comprising:

means, which calculates an intake air quantity per unit time and an intake air quantity per cycle on the basis of torque required to the internal combustion engine;

means, which controls a turbocharger so that with the intake air quantity per unit time, supercharging pressure is further increased in that range, in which a ratio of supercharging pressure and exhaust pressure is equal to or less than a predetermined value; and

means, which controls a variable valve mechanism on the basis of the supercharging pressure and the intake air quantity per cycle.