APPARATUS FOR AND METHOD OF CONTROLLING VARIABLE VALVE MECHANISM

• US 20090088954A1
• Filed: 08/28/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: MACHIDA, Kenichi
• Application Number:
  US12/200,343
• Publication Number:
  US 20090088954A1
• Time in Patent Office: Days
• US Class Current: 701/105
• CPC Class Codes: F01L 13/0015 for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
• CPC Class Codes: F01L 13/0026 by means of an eccentric
• CPC Class Codes: F01L 2013/0073 with an oscillating cam acting on the valve of the "Delphi" type
• CPC Class Codes: F01L 2820/032 Electric motors
• CPC Class Codes: F01L 2820/041 Camshafts position or phase sensors

Abstract

An apparatus for and method of controlling a variable valve mechanism capable of continuously varying an effective opening of an intake valve by driving of an actuator, and also, is provided with a default mechanism which mechanically holds the intake valve at a default opening set to be larger than a minimum effective opening when the driving of the actuator is stopped, while the intake valve is being held at the default opening by the default mechanism, the effective opening of the intake valve is detected, the default opening is detected based on the detected effective opening to thereby learning the default opening, so that a direction of supply of a driving force by the actuator is switched between an increase-direction causing an increase in the effective opening and a decrease-direction causing a decrease therein, from the detected or learned default opening.

Claims

1. An apparatus for controlling a variable valve mechanism capable of continuously varying an effective opening of an engine valve provided for an engine, comprising:

an actuator configured to drive the variable valve mechanism;

a default mechanism provided to be incorporated in the variable valve mechanism to mechanically hold the engine valve at a default opening set to be larger than a minimum effective opening at a time when the driving of the actuator is stopped;

a valve opening detector configured to detect the effective opening of the engine valve; and

a control unit including a default opening learning section that learns the default opening, based on the effective opening of the engine valve detected by the valve opening detector while the engine valve is being held at the default opening by the default mechanism.

2. The apparatus according to claim 1, further comprising;

an operating state detector configured to detect engine operating state of the engine,

wherein the control unit further comprises;

a predetermined operating state judging section that judges whether or not the engine stays at a predetermined engine operating state in which, irrespective of holding of the engine valve at the default opening by the default mechanism, any influence from the engine valve on the engine operability can be neglected, and

wherein the default opening learning section is capable of stopping the driving of the actuator when it is judged that the engine stays at the predetermined engine operating state thereby holding the engine valve at the default opening thereof to implement learning of the default opening.

3. The apparatus according to claim 2, wherein the predetermined engine operating state of the engine is an operating state where an exhaust purifying function of the engine is maintained at a good performance level when the engine valve is held at the default opening thereof.

4. The apparatus according to claim 2, wherein the predetermined engine operating state of the engine is a state selected from a time of starting of the engine operation, a time of stopping of the engine operation, and a time of cutting off of fuel supply.

5. The apparatus according to claim 4, wherein the control unit further comprises;

a throttle opening correcting section configured to correctively increase an opening of a throttle valve disposed in an intake system to compensate for shortage of intake air at the default opening of the engine valve relative to a required amount of the intake air, when the learning is performed by the default opening learning section at the time of starting of the engine operation.

6. The apparatus according to claim 1, wherein the control unit further comprises;

a parameter characteristics correcting section configured to correct characteristics of engine control parameters which depend on the effective opening of the engine valve, based on a result of the learning of the default opening by the default opening learning section.

7. The apparatus according to claim 6, wherein the parameter characteristics correcting section correctively increases a fuel injection amount and corrects ignition timing toward a retarded angle side, when the default opening of the engine valve is deviated to increase with respect to a reference opening thereof, and on the other hand, correctively decrease the fuel injection amount and corrects the ignition timing toward an advance angle side, when the default opening of the engine valve is deviated to decrease with respect to the reference opening.

8. The apparatus according to claim 1, wherein the control unit further comprises;

a default mechanism diagnosing section configured to judge the default mechanism to be in an abnormal state, when the default opening of the engine valve learned by the default opening learning section comes outside a predetermined region for implementing judgment as to whether or not the default mechanism is in the abnormal state.

9. The apparatus according to claim 8, wherein the default mechanism diagnosing section stores, when the judgment indicates that the default mechanism is in the abnormal state, a result of the judgment and implements a warning.

10. The apparatus according to claim 8, wherein the control unit further comprises;

a control changing-over section configured to changes-over control of an intake air amount achieved by mainly a throttle valve disposed in an intake system from that achieved by mainly the variable valve mechanism, when the default mechanism diagnosing section judges that the default mechanism is in the abnormal state.

11. The apparatus according to claim 10, wherein the control changing-over section controls the throttle valve so that an intake pressure is kept at a target intake pressure that is set according to the engine operating state of the engine, when the default mechanism diagnosing section judges that the default mechanism is in a normal state.

12. The apparatus according to claim 1, wherein the control unit further comprises;

an actuator controlling and correcting section configured to switch a direction of supply of a driving force by the actuator between an increase-direction causing an increase in the effective opening and a decrease-direction causing a decrease therein, from the learned default opening of the engine valve.

13. An apparatus for controlling a variable valve mechanism capable of continuously varying an effective opening of an engine valve of an engine, comprising:

an actuator configured to drive the variable valve mechanism;

a default mechanism provided to be incorporated in the variable valve mechanism, which mechanically holds the engine valve at a default opening that is set to be larger than a minimum effective opening of the engine valve at a time when driving of the actuator is stopped; and

control unit comprising;

a default mechanism diagnosing section that judges whether or not the default mechanism is in an abnormal state; and

a control changing-over section that implements an intake air amount controlling by mainly the variable valve mechanism when the default mechanism diagnosing section judges that the default mechanism is in a normal state, and also changes-over the intake air amount controlling to that by mainly an electronically controlled throttle when the default mechanism diagnosing section judges that the default mechanism is in an abnormal state.

14. An apparatus for controlling a variable valve mechanism capable of continuously varying an effective opening of an engine valve of an engine, comprising:

an actuator configured to drive the variable valve mechanism;

a default mechanism provided to be incorporated in the variable valve mechanism, which mechanically holds the engine valve at a default opening that is set to be larger than a minimum effective opening of the engine valve at a time when driving of the actuator is stopped; and

a control unit comprising;

a default opening detecting section that detects the default opening of the engine valve, based on the effective opening detected by the valve opening detector in a state where the effective opening is held at the default opening by the default mechanism; and

a parameter characteristics correcting section that correctively increases a fuel injection amount and/or corrects ignition timing toward a retarded angle side, when the default opening is deviated to increase relative to a reference opening of the engine valve, and on the other hand, correctively decreases the fuel injection amount and/or corrects the ignition timing toward an advance angle side, when the default opening of the engine valve is deviated to decrease relative to the reference opening of the engine valve.

15. An apparatus for controlling a variable valve mechanism capable of continuously varying an effective opening of an engine valve of an engine, comprising:

an actuator configured to drive the variable valve mechanism;

a default mechanism provided to be incorporated in the variable valve mechanism, which mechanically holds the engine valve at a default opening that is set to be larger than a minimum effective opening of the engine valve at a time when driving of the actuator is stopped;

valve opening detecting means for detecting the effective opening of the engine valve; and

default opening learning means for learning the default opening, based on the effective opening of the engine valve detected by the valve opening detecting means.

16. A method of controlling a variable valve mechanism capable of continuously varying an effective opening of an engine valve of an internal combustion engine, the method comprising the steps of:

driving the variable valve mechanism by an actuator while mechanically holding the engine valve at a default opening that is set to be larger than a minimum effective opening of the engine valve by a default mechanism, at a time when driving of the actuator is stopped;

detecting the effective opening of the engine valve in a state where the engine valve is held at the default opening by the default mechanism; and

learning the default opening, based on the effective opening of the engine valve detected while the engine valve is being held at the default opening thereof.

17. The method according to claim 16, further comprising the steps of:

detecting engine operating state; and

judging whether the engine operating state is a state selected from a time of starting of an engine operation, a time of stopping of the engine operation, or a time of cutting off fuel supply, wherein when it is judged that the engine operating state is any one thereof, the driving of the actuator is stopped and the engine valve is held at the default opening to thereby learn the default opening.

18. The method according to claim 16, further comprising the step of;

correctively increasing an opening of a throttle valve disposed in an intake system to correct shortage of intake air in the default opening relative to a required intake air amount, when the learning is implemented by the default opening learning step at the time of starting of the engine operation.

19. The method according to claim 16, further comprising the step of;

correctively increasing a fuel injection amount and correcting ignition timing toward a retarded angle side thereof, when the default opening is deviated to increase relative to a reference opening of the engine valve, and while, correctively decreasing the fuel injection amount and correcting the ignition timing toward an advance angle side, when the default opening is deviated to decrease relative to the reference opening, based on a result of the learning of the default opening of the engine valve by the step of learning the default opening.

20. The method according to claim 16, further comprising the steps of:

judging, when the default opening learned by the learning step is outside a predetermined region for judgment of the abnormal state of the default mechanism, that the default mechanism is in an abnormal state; and

changing-over control of an intake air amount by mainly a throttle valve disposed in an intake system from that by mainly the variable valve mechanism, when the judgment indicates that the default mechanism is in the abnormal state.