JP2005264764A - Valve timing control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid the mismatching of the control of an engine at starting with an actual valve timing by determining whether a variable valve timing mechanism is locked or not to an intermediate phase by a lock pin. <P>SOLUTION: The lock is determined to be performed normally when the actual relative phase is fixed to a fitted position under the condition that the lock pin is projected after being converged to an advance-angle side from the fitted position of the lock pin to a pin hole and then the drive duty of an actuator is changed to a position spark-advanced beyond the fitted position. When the lock is not performed, the actuator is controlled toward the fitted position or a fuel control and an ignition control at start are switched to a characteristic corresponding to the most-spark retard angle at a next start. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is configured to continuously change the valve timing of the engine valve by continuously changing the relative phase of the camshaft with respect to the crankshaft, and locks the relative phase to a predetermined intermediate phase. The present invention relates to a valve timing control device for an internal combustion engine having a lock mechanism.

Conventionally, a variable valve timing mechanism is known when the relative phase of the camshaft with respect to the crankshaft of the internal combustion engine is continuously variable. In the one disclosed in Patent Document 1, an intermediate phase that is a relative phase for starting is known. A configuration is disclosed in which a lock pin for locking in a phase is provided, and the lock is released by hydraulic pressure during operation of the engine, while the lock pin is projected by a spring force and locked to the intermediate phase when the engine is stopped.
JP 2001-050063 A

  By the way, in the past, since it was not determined whether or not the lock pin was actually locked, the relative phase was changed to the most retarded angle side due to the urging force of the return spring without being locked due to the lock pin sticking or the like. Even if the engine is stopped while the relative phase is being changed toward the intermediate phase and cannot be locked as a result, the engine control at the start is based on the assumption that the intermediate phase is locked by the lock pin. As a result, there is a problem that startability and exhaust emission are deteriorated due to inconsistency between the engine control at the start and the actual valve timing.

  The present invention has been made in view of the above problems, and can determine whether or not the lock pin is actually locked to the intermediate phase, so that the engine control at the start and the actual valve timing are inconsistent. An object of the present invention is to provide a valve timing control device for an internal combustion engine that can avoid this.

Therefore, the invention described in claim 1 includes a first rotating body that is pivotally supported by a camshaft, a second rotating body that is arranged coaxially with the first rotating body and rotates in synchronization with a crankshaft, and the first rotation. An assembly angle changing mechanism for continuously changing the assembly angle between the body and the second rotating body by an actuator, and by continuously changing the assembly angle, the relative phase of the camshaft with respect to the crankshaft is continuous. And a locking mechanism that locks the relative phase to a predetermined intermediate phase by locking the assembly angle of the first rotating body and the second rotating body to a predetermined intermediate angle. In the valve timing control device of
After the engine stop request is generated, the actuator is controlled toward the predetermined intermediate phase and the lock mechanism is operated.
Based on the correlation between the operation amount of the actuator after the operation of the lock mechanism and the detection result of the relative phase, it is determined whether or not it is locked to the predetermined intermediate phase.

According to such a configuration, when the lock mechanism is activated and actually locked to the intermediate phase (starting phase), the relative phase is fixed to the intermediate phase even if the relative phase is subsequently changed. Therefore, when the relative phase changes from the intermediate phase, it is determined that the lock by the lock mechanism did not function normally.
Therefore, it is possible to determine whether or not the lock has been normally performed without using a sensor for the lock mechanism, and the determination result can be used for lock control, fuel injection amount, fuel injection timing, ignition timing, etc. at the next start. By reflecting it in the engine control, it becomes possible to avoid deterioration in engine operability.

According to the second aspect of the present invention, when the engine is not locked to the predetermined intermediate phase at the previous engine stop, the relative phase is set to the most retarded angle side at the start, and the engine control at the start is performed to the most retarded angle. The control is switched to the control corresponding to the state.
According to such a configuration, in preparation for the next start, the engine is stopped and locked to the intermediate phase for starting, but if the locking is not possible, the relative phase is set to the most retarded side at the start and the most retarded state The control at the time of start corresponding to is executed.

Therefore, even if the relative phase for starting cannot be locked, the actual relative phase can be matched with the engine control at the time of starting, and a significant deterioration in startability and exhaust emission can be avoided.
Note that setting the relative phase to the most retarded angle side at start includes not only mechanically returning to the most retarded angle side by the urging force of the return spring but also controlling the actuator to the most retarded angle side. And

According to a third aspect of the present invention, when the engine is not locked to the predetermined intermediate phase at the time of the previous engine stop, the actuator is controlled to be the predetermined intermediate phase at the start.
According to such a configuration, when it is determined that the engine could not be locked at the previous engine stop, the actuator is controlled so that the intermediate phase (starting phase) is reached at the time of starting, and at the time of starting suitable for the locked state To be able to apply the engine control.

Therefore, even when the engine cannot be locked normally, a good startability can be realized by executing the engine control at the time of starting normally.
According to the fourth aspect of the present invention, when it is determined that the actuator is not locked to the predetermined intermediate phase, the actuator and the lock mechanism are controlled again to lock the predetermined intermediate phase.

According to such a configuration, when the locking cannot be performed normally, the control for locking to the intermediate phase (starting phase) is executed again.
Therefore, when it is temporarily impossible to lock to the intermediate phase, locking to the intermediate phase can be realized.
According to a fifth aspect of the present invention, a relative phase detection unit capable of detecting the relative phase at an arbitrary timing is provided, and the actuator is feedback-controlled based on a detection result of the relative phase detection unit.

  According to this configuration, the relative phase detection unit can detect the relative phase at an arbitrary timing, and thus can quickly control the relative phase to the target relative phase without causing overshoot.

FIG. 1 is a system configuration diagram of an internal combustion engine for a vehicle according to an embodiment.
In FIG. 1, an electronic control throttle 104 that opens and closes a throttle valve 103 b by a throttle motor 103 a is interposed in an intake pipe 102 of the internal combustion engine 101, and a combustion chamber 106 is connected via the electronic control throttle 104 and the intake valve 105. Air is inhaled inside.
The combustion exhaust is discharged from the combustion chamber 106 through the exhaust valve 107, purified by the front catalyst 108 and the rear catalyst 109, and then released into the atmosphere.

  The intake valve 105 and the exhaust valve 107 are driven to open and close by cams provided on the exhaust side camshaft 110 and the intake side camshaft 134, respectively, but the intake side camshaft 134 side has an intake side cam for the crankshaft 120. A variable valve timing mechanism (hereinafter abbreviated as VTC) 113 that continuously changes the center phase of the operating angle of the intake valve 105 by changing the relative phase of the shaft 134 is provided.

Further, an electromagnetic fuel injection valve 131 is provided in the intake port 130 upstream of the intake valve 105 of each cylinder.
When the fuel injection valve 131 is driven to open by an injection pulse signal from an engine control unit (hereinafter abbreviated as ECU) 114, the fuel adjusted to a predetermined pressure is injected toward the intake valve 105.

The ECU 114 includes a microcomputer, and controls the electronic control throttle 104, the VTC 113, the fuel injection valve 131, and the like by arithmetic processing based on detection signals from various sensors.
The various sensors include an accelerator opening sensor 116 for detecting the accelerator opening, an air flow meter 115 for detecting the intake air amount Q of the engine 101, and a crankshaft 120 for each reference crank angle position (every crank angle 180 ° for four cylinders). ) Of the reference crank angle signal REF and the unit angle signal POS for each unit crank angle, a throttle sensor 118 for detecting the opening TVO of the throttle valve 103b, and a water temperature sensor 119 for detecting the cooling water temperature of the engine 101. A cam sensor 132 for taking out a cam signal CAM for each reference cam angle (a cam angle corresponding to a crank angle of 180 ° every 90 °) is provided from the intake camshaft 134.

The ECU 114 calculates the engine speed Ne based on the rotation signal output from the crank angle sensor 117.
Next, the configuration of the VTC 113 will be described with reference to FIGS.
As shown in FIG. 2, the VTC 113 is assembled to the intake-side camshaft 134 and the front end portion of the camshaft 134 so as to be able to relatively rotate as necessary, via a chain (not shown). A drive ring 303 (drive rotator, second rotator) having a timing sprocket 302 linked to the crankshaft 120 on the outer periphery, and the drive ring 303 and the front side of the camshaft 13 (left side in FIG. 2). An assembly angle operation mechanism 304 (assembly angle change mechanism) for operating the assembly angles of both 303 and 301, and an operation that is disposed further forward of the assembly angle operation mechanism 304 and drives the mechanism 304. A force applying means 305, an assembly angle operating mechanism 304 and an operating force applying means 305 which are mounted across the cylinder head (not shown) of the internal combustion engine and the front surface of the head cover. It includes a non-illustrated VTC cover for covering the front and periphery areas, a.

The drive ring 303 is formed in a short cylindrical shape having a step-like insertion hole 306, and the insertion hole 306 portion is a driven shaft member 307 (driven rotor, first driven body) coupled to the front end portion of the camshaft 13. (Rotating body) is rotatably assembled.
As shown in FIG. 3, three radial grooves 308 (radial guides) having parallel side walls facing each other are provided on the front surface (the surface opposite to the camshaft 13) of the drive ring 303. It is formed so as to be along the substantially radial direction.

Further, as shown in FIG. 2, the driven shaft member 307 has a diameter-enlarged portion formed on the outer periphery on the base side that is abutted against the front end portion of the camshaft 13, and is formed on the outer peripheral surface on the front side of the enlarged-diameter portion. Three levers 309 projecting radially are integrally formed and coupled to the camshaft 13 by bolts 310 penetrating the shaft core portion.
The base end of each link 311 is pivotally connected to each lever 309 by a pin 312, and a columnar protrusion 313 slidably engaged with each radial groove 308 is integrally formed at the tip of each link 311. Is formed.

  Since each link 311 is connected to the driven shaft member 307 via the pin 312 in a state where the protruding portion 313 is engaged with the corresponding radial groove 308, the distal end side of the link 311 receives an external force and receives the radial groove. When displaced along 308, the drive ring 303 and the driven shaft member 307 are relatively rotated by the action of the link 311 by a direction and an angle corresponding to the displacement of the protrusion 313.

In addition, a housing hole 314 that opens to the front side in the axial direction is formed at the tip of each link 311, and the housing hole 314 has a spherical protrusion 316 a that engages with a spiral groove 315 (spiral guide) described later. An engagement pin 316 (rolling member) and a coil spring 317 that biases the engagement pin 316 forward (spiral groove 315 side) are accommodated.
In this embodiment, a movable guide portion that is displaceable in the radial direction is constituted by the protruding portion 313 at the tip of the link 311, the engaging pin 316, the coil spring 317, and the like.

On the other hand, an intermediate rotating body 318 having a disk-like flange wall 318 a is rotatably supported via a bearing 331 in front of the protruding position of the lever 309 of the driven shaft member 307.
The aforementioned spiral groove 315 having a semicircular cross section is formed on the rear surface side of the flange wall 318a of the intermediate rotating body 318, and the engagement pin 316 at the tip of each link 311 can freely roll in the spiral groove 315. Is engaged with the guide.

The spiral of the spiral groove 315 is formed so as to gradually reduce the diameter along the rotation direction of the drive ring 303.
Accordingly, in the state where the engagement pin 316 at the tip of each link 311 is engaged with the spiral groove 315, when the intermediate rotating body 318 rotates relative to the drive ring 303 in the delay direction, the tip of the link 311 becomes the radial groove 308. When the intermediate rotating body 318 is relatively displaced in the advancing direction, it is guided radially by the spiral shape of the spiral groove 315 and conversely moves in the radial direction.

The assembly angle operation mechanism 304 of this embodiment is constituted by the radial groove 308, the link 311, the protrusion 313, the engagement pin 316, the lever 309, the intermediate rotating body 318, the spiral groove 315, etc. of the drive ring 303 described above. Has been.
When the relative rotation operation force with respect to the camshaft 13 is input from the operation force applying means 305 to the intermediate rotating body 318, the assembly angle operation mechanism 304 receives the operation force from the spiral groove 315 and the engagement pin 316. The distal end of the link 311 is displaced in the radial direction through the engaging portion, and at this time, relative rotational force is transmitted to the drive link 303 and the driven shaft member 307 by the action of the link 311 and the lever 309.

  On the other hand, the operating force applying means 305 brakes the mainspring 319 for biasing the intermediate rotator 318 in the rotation direction of the drive ring 303 and the intermediate spring 318 for biasing in the direction opposite to the rotation direction of the drive ring 303. And a hysteresis brake 320 as a mechanism, and by appropriately controlling the braking force of the hysteresis brake 320 according to the operating state of the internal combustion engine, the intermediate rotating body 318 is rotated relative to the drive ring 303, Or the rotation position of both of them is maintained.

The spring spring 319 has an outer peripheral end coupled to a cylindrical member 321 integrally attached to the drive ring 303, while an inner peripheral end is coupled to a cylindrical base of the intermediate rotating body 318, and the whole is intermediate. The rotating body 318 is disposed in the space on the front side of the flange wall 318a.
On the other hand, the hysteresis brake 320 is restricted in rotation by a bottomed cylindrical hysteresis ring 323 attached to the front end portion of the intermediate rotating body 318 via a retainer plate 322, and a VTC cover (not shown) which is a non-rotating member. An electromagnetic coil 324 (actuator) as a magnetic field control means attached in a state, and a coil yoke 325 which is a magnetic induction member for guiding the magnetism of the electromagnetic coil 324, and the electromagnetic coil 324 is in accordance with the operating state of the engine. The ECU 114 is energized and controlled.

As shown in FIG. 6, the hysteresis ring 323 is formed of a hysteresis material (semi-hard material) having a characteristic (magnetic hysteresis characteristic) in which magnetic flux force changes with a phase lag with respect to a change in an external magnetic field. The cylindrical wall 323a is subjected to a braking action by the coil yoke 325.
The entire coil yoke 325 is formed in a substantially cylindrical shape so as to surround the electromagnetic coil 324, and an inner peripheral surface thereof is rotatably supported by the tip end portion of the driven shaft member 307 via a bearing 328.

A pair of circumferential facing surfaces 326 and 327 are formed on the rear surface side (intermediate rotating body 318 side) of the coil yoke 325 so that the magnetic input / output portions face each other with a cylindrical gap.
Also, as shown in FIG. 4, a plurality of concavities and convexities are continuously formed along the circumferential direction on both facing surfaces 326 and 327 of the coil yoke 325, and the convex portions 326a and 327a of these concavities and convexities are formed as magnetic poles. (Magnetic field generator).

And the convex part 326a of one opposing surface 326 and the convex part 327a of the other opposing surface 327 are alternately arrange | positioned in the circumferential direction, and the convex parts 326a and 327a which the opposing surfaces 326 and 327 mutually adjoin are all the circumferential direction. It is shifted to.
Therefore, a magnetic field having an inclination in the circumferential direction as shown in FIG. 7 is generated by the excitation of the electromagnetic coil 24 between the adjacent convex portions 326a and 327a of the opposing surfaces 326 and 327.

A cylindrical wall 323a of the hysteresis ring 323 is interposed in a non-contact state in the gap between the opposing surfaces 326 and 327.
Here, the operating principle of the hysteresis brake 320 will be described with reference to FIG.
8A shows a state in which a magnetic field is first applied to the hysteresis ring 323 (hysteresis material), and FIG. 8B shows a state in which the hysteresis ring 323 is displaced (rotated) from the state (a). Indicates the state.

In the state of FIG. 8A, the direction of the magnetic field between the opposing surfaces 326 and 327 of the coil yoke 325 (the direction of the magnetic field from the convex portion 327a of the opposing surface 27 toward the convex portion 327a of the other opposing surface 326) is met. Thus, a magnetic flux flows in the hysteresis ring 323.
If the hysteresis ring 323 is moved by receiving an external force F as shown in FIG. 8B from this state, the hysteresis ring 323 is displaced in the external magnetic field. At this time, the magnetic flux inside the hysteresis ring 323 is phase-shifted. There is a delay, and the direction of the magnetic flux inside the hysteresis ring 323 is deviated (tilted) with respect to the direction of the magnetic field between the opposing surfaces 326 and 327.

  Accordingly, the flow of magnetic flux (magnetic lines) entering the hysteresis ring 323 from the convex portion 327a of the opposing surface 327 and the flow of magnetic flux (magnetic lines) from the hysteresis ring 323 toward the convex portion 326a of the other opposing surface 326 are distorted. An attractive force that corrects the distortion of the magnetic flux acts between the opposing surfaces 326 and 327 and the hysteresis ring 323, and the attractive force acts as a drag force F ′ that brakes the hysteresis ring 323.

  When the hysteresis ring 323 is displaced in the magnetic field between the opposing surfaces 326 and 327 as described above, the hysteresis brake 320 generates a braking force due to the deviation of the direction of the magnetic flux inside the hysteresis ring 323 and the direction of the magnetic field. However, the braking force depends on the strength of the magnetic field, that is, the magnitude of the excitation current of the electromagnetic coil 324, regardless of the rotational speed of the hysteresis ring 323 (relative speed between the opposed surfaces 326 and 327 and the hysteresis ring 323). It becomes a constant value approximately proportional to.

  The VTC 113 according to this embodiment is configured as described above, and when the excitation of the electromagnetic coil 324 of the hysteresis brake 320 is turned off, the intermediate rotating body 318 is engineed against the drive ring 303 by the urging force of the mainspring spring 319. The position of the engagement pin 316 is regulated at a position where the engagement pin 316 hits the outer peripheral side end face 315a of the spiral groove 315, and this position becomes the most retarded position of the relative phase that can be changed on the mechanism of the VTC 113 (see FIG. 3).

  When the excitation of the electromagnetic coil 324 is turned on from this state, a braking force against the force of the mainspring spring 319 is applied to the intermediate rotating body 318, and the intermediate rotating body 318 rotates in the reverse direction with respect to the drive ring 303, As a result, the engaging pin 316 at the tip of the link 311 is guided into the spiral groove 315, whereby the tip of the link 311 is displaced along the radial groove 308, and the drive ring 303 and the driven shaft member 307 are acted upon by the link 11. The assembly angle is changed to the advance side.

When the exciting current of the electromagnetic coil 324 is increased to increase the braking force, the engagement pin 316 is finally regulated at a position where it abuts against the inner peripheral side end surface 315b of the spiral groove 315, and this position is determined by the VTC 113. It becomes the most advanced position of the relative phase that can be changed on the mechanism (see FIG. 5).
When the exciting current of the electromagnetic coil 324 is reduced from this state and the braking force is reduced, the intermediate rotating body 318 is rotated back in the forward direction by the urging force of the mainspring spring 319 and is linked by the induction of the engaging pin 316 by the spiral groove 315. 311 swings in the opposite direction, and the assembly angle of the drive ring 303 and the driven shaft member 307 is changed to the retard side.

  As described above, the relative phase of the camshaft 13 (the central phase of the operating angle of the intake valve 105) with respect to the crankshaft 120 that is varied by the VTC 113 controls the exciting current value of the electromagnetic coil 324 and the braking force of the hysteresis brake 320. And the phase can be maintained by the balance between the force of the mainspring spring 319 and the braking force of the hysteresis brake 320.

  Further, in the VTC 113 of this embodiment, the lock pin 351 supported on the drive ring 303 side is fitted into the pin hole 352 provided in the intermediate rotating body 318 in which the spiral groove 315 is formed, so that the drive ring The relative rotation of the intermediate rotator 318 with respect to 303 is restricted, and the position of the engagement pin 316 in the radial groove 308 is fixed, so that the intermediate phase determined by the fitting position of the lock pin 351 and the pin hole 352 A locking mechanism is provided for locking.

The intermediate phase is a relative phase required at start-up that is advanced from the most retarded position.
The lock pin 351 is biased in a direction protruding toward the intermediate rotating body 318 by a spring force, and is controlled by an electromagnetic actuator 353 controlled by the ECU 114 (or a hydraulic actuator whose supply hydraulic pressure is controlled by an electromagnetic valve). It is pulled back toward the drive ring 303 against the spring force.

Since the intermediate rotator 318 is biased to the most retarded angle side by the mainspring spring 319, when the engine is stopped in the unlocked state by the locking mechanism and the braking force of the hysteresis brake 320 does not work (the key switch When OFF), the position returns to the most retarded position.
However, if locking is performed by the lock mechanism, the engine is stopped and the position corresponding to the relative phase required at the start is fixed, and at the next start, if the engine is started in the locked state, The engine operation at the relative phase (valve timing) required at the start can be realized from the start of the start.

The VTC 113 is not limited to the one having the above configuration, and may be a hydraulic vane type variable valve timing mechanism as disclosed in Japanese Patent Laid-Open No. 2001-050063.
Here, the control of the lock mechanism (electromagnetic actuator 353) when the engine is stopped by the ECU 114 will be described with reference to the flowchart of FIG.

In step S1, it is determined whether or not the ignition key switch is turned off.
In this embodiment, as will be described later, after the ignition key switch is turned off, the lock control of the VTC 113 is completed, and then the engine is stopped.
When the ignition key switch is turned off, that is, when an engine stop request is generated, the process proceeds to step S2.

In step S2, the target angle of the VTC 113 (target advance value of relative phase) is advanced by a predetermined value α from the target angle for start (relative phase for start) when the lock pin 351 is fitted in the pin hole 352. The value on the side is set (see FIG. 13).
In step S3, the excitation current value of the electromagnetic coil 324 is feedback-controlled so that the actual angle matches the target angle.

The actual angle is detected as the angle from the timing when the reference crank angle signal REF is output from the crankshaft 120 to the time when the cam signal CAM is output from the cam sensor 132.
However, in the configuration in which the relative phase is detected based on the phase difference between the reference crank angle signal REF and the cam signal CAM, the detection result of the relative phase is updated at every constant crank angle, and the detection delay particularly at a low rotation speed. Increases and overshoot occurs.

Therefore, it is preferable to provide means capable of detecting the relative phase at an arbitrary timing, for example, to update and detect the relative phase every minute time and feedback control the excitation current value of the electromagnetic coil 324.
The means capable of detecting the relative phase at an arbitrary timing can be realized by the following configuration.
As shown in FIG. 9, the gap sensor is formed so that the radius of the rotating body 133a that rotates integrally with the camshaft 134 changes continuously in the circumferential direction, and is fixed to face the periphery of the rotating body 133a. As shown in FIG. 10, the output of 133b is configured to change continuously as the distance (gap) between the gap sensor 133b and the periphery of the rotating body 133a changes as the camshaft 134 rotates.

Here, since the relationship between the angular position of the camshaft and the gap is constant, as shown in FIG. 11, the output of the gap sensor 133b and the angular position of the camshaft 134 have a certain correlation, and The angular position of the camshaft 134 can be detected from the output of the gap sensor 133b.
On the other hand, if the number of occurrences of the unit angle signal POS from the reference crank angle signal REF is always counted, the angular position of the crankshaft 120 can be obtained at an arbitrary timing with the minimum unit being 10 °. The relative phase can be obtained at an arbitrary timing (every predetermined minute time) from the angular position of 120 and the angular position of the camshaft 134.

Instead of using the gap sensor 133b, it is possible to use a relative phase sensor whose output changes in accordance with the change in the relative phase.
In step S4, it is determined whether or not the actual angle (actual relative phase) has converged to the target angle (target phase) that is advanced by a predetermined value α from the target angle for starting (relative phase for starting). Determine.

The convergence to the target angle is determined based on whether or not the control deviation is a predetermined value or less.
When it converges to the target angle, the process proceeds to step S5, and control is performed to project the lock pin 351.
However, since the convergence position is an advance side by a predetermined value α from the target angle for starting, even if the lock pin 351 protrudes, the pin hole 352 does not exist at the opposite position, and the lock pin 351 is Then, it is pressed against the end face of the intermediate rotating body 318 (see FIG. 13).

In step S <b> 6, whether or not the lock pin 351 is actually pressed against the end surface of the intermediate rotating body 318 is determined by determining whether or not a predetermined time has elapsed since the control for causing the lock pin 351 to protrude. Determine whether or not.
When the predetermined time has elapsed, the process proceeds to step S7, where the relative phase is gradually retarded by decreasing the duty value (ON time ratio) for controlling the excitation current of the electromagnetic coil 324 at a constant speed (see FIG. 13). ).

In step S8, it is determined whether or not the duty value is smaller than a predetermined value β.
The predetermined value β is a value corresponding to the relative phase on the retard side from the position where the lock pin 351 is fitted in the pin hole 352, and when the duty value is smaller than the predetermined value β, In terms of control, the lock pin 351 has passed the relative phase of fitting into the pin hole 352, and if the lock pin 351 protrudes normally, the lock pin 351 and the pin hole 352 are aligned coaxially. Sometimes the lock pin 351 fits into the pin hole 352 and should be locked.

Therefore, if it is determined in step S8 that the duty value has become smaller than the predetermined value β, the process proceeds to step S9, and the detection result of the relative phase indicates that the target angle for starting at which the lock pin 351 is fitted in the pin hole 352 is obtained. It is determined whether or not.
When it is determined in step S9 that the target angle for starting is reached, it can be determined that the lock pin 351 is fitted in the pin hole 352, and in this case, the process proceeds to step S10 to fix the VTC initial position. Set 1 to the determination flag.

On the other hand, when it is determined that the target angle for starting is not reached, it can be determined that the lock pin 351 does not normally protrude due to the fixing of the lock pin 351 and the like, and the target angle for starting cannot be locked. It progresses to S11 and it is discriminate | determined whether the frequency | count of repetition execution of lock control (step S2-step S7) is more than predetermined value.
If the target angle for starting cannot be locked after repeating the predetermined number of times, the process proceeds to step S12, and 0 is set to the VTC initial position fixing determination flag.

The predetermined value may be set once, and when the lock control in steps S2 to S7 is executed once, the process may immediately proceed to step S12.
In step S13, energization of the electromagnetic coil 324 is stopped.
Even if the energization of the electromagnetic coil 324 is stopped, if the lock mechanism functions normally, the relative phase will remain fixed at the starting target angle. If it does not function, it returns to the most retarded angle side by the urging force of the mainspring spring 319 and is fixed at that position.

In step S14, the engine is stopped (fuel injection / ignition is stopped).
The VTC initial position fixing determination flag is used at the time of starting as shown in the flowchart of FIG.
In the flowchart of FIG. 14, in step S21, it is determined whether or not cranking is in progress.

When cranking is in progress, the process proceeds to step S22, where it is determined whether or not the VTC initial position fixing determination flag is zero.
If the VTC initial position fixing determination flag is 0, the engine cannot be locked to the starting target angle at the previous engine stop, and the relative phase is at the most retarded angle side, the process proceeds to step S23, where the target angle The feedback control of the VTC 113 is performed with the target angle for starting.

Also in the feedback control in step S23, it is preferable to use means (gap sensor 133b) that can detect the relative phase at an arbitrary timing.
Since the fuel injection amount, fuel injection timing, and ignition timing during cranking (starting) are set based on the target angle for starting locked by the locking mechanism, the actual angle (relative phase) Until the target angle for starting (relative phase for starting) converges, the actual relative phase (valve timing) and engine control are inconsistent, but could not be locked when the previous engine stopped Based on this, control toward the target angle for starting can be performed immediately, so that the target angle for starting is quickly converged and the actual relative phase (valve timing) and engine control are matched. Can be performed.

Note that the lock pin 351 is held in the protruding state until the process of releasing the protrusion of the lock pin 351 in step S30 described later, so that the lock pin 351 is fitted into the pin hole 352 by the process of step S23. In some cases.
On the other hand, when it is determined in step S22 that the VTC initial position fixing determination flag is 1, the VTC 113 is controlled because it is normally locked at the target angle for starting (relative phase for starting). Instead, the fuel injection / ignition timing at the start is controlled.

If it is determined in step S21 that cranking is not in progress (after cranking is completed), the process proceeds to step S24.
In step S24, it is determined whether or not the target angle of the VTC 113 set based on the water temperature, the engine load, the engine speed, and the like is the target angle for starting.
Then, while the target angle is the starting target angle, the process proceeds to step S22 and subsequent steps.

On the other hand, if the target angle is no longer the target angle for starting, the process proceeds to step S25, and the protrusion of the lock pin 351 is released by operating the actuator, and it is possible to change to an angle other than the target angle for starting. The VTC initial position fixing determination flag is reset to zero.
In step S26, feedback control of the electromagnetic coil 324 is performed based on the deviation between the target angle and the actual angle (relative phase).

The flowchart of FIG. 15 shows a second embodiment of start control using the VTC initial position fixing determination flag.
In the second embodiment shown in the flowchart of FIG. 15, when it is determined in step S22 that the VTC initial position fixing determination flag is 0, and it has not been possible to lock to the target angle for starting at the time of the previous engine stop, step S23A When proceeding to, the setting of the fuel injection amount, fuel injection timing, and ignition timing during cranking is switched to a setting that matches the most retarded state stored in advance.

That is, the fuel injection amount / fuel injection timing / ignition timing setting characteristics that match the target angle for starting (lock position) in advance and the fuel injection amount / fuel injection timing / ignition timing setting characteristics that match the most retarded angle state Remember.
If the target angle for starting cannot be locked at the previous engine stop, it is determined that the VTC 113 returns to the most retarded angle side by the urging force of the mainspring spring 319 and is fixed at that position. If the engine control at the start is performed with the setting characteristics of the fuel injection amount, fuel injection timing, and ignition timing that match the most retarded angle state, and the target angle for starting can be locked at the previous engine stop Then, the engine control at the start is performed with the setting characteristics of the fuel injection amount, the fuel injection timing, and the ignition timing suitable for the target angle for starting (lock position).

According to this configuration, when the engine cannot be locked at the start of the engine, the valve timing during cranking is not optimally set, but the actual valve timing and the engine control characteristics do not become inconsistent, and startability is improved. A great deterioration can be avoided.
Note that if the target engine angle cannot be locked at the time of the previous engine stop, the fuel injection amount / fuel injection timing / ignition timing is adjusted to the most retarded angle after actively controlling to the most retarded angle. You may make it perform engine control at the time of a start with a setting characteristic.

Here, technical ideas other than the claims that can be grasped from the above embodiment will be described together with the effects thereof.
(A) In the valve timing control apparatus for an internal combustion engine according to any one of claims 1 to 5,
It converges at a position deviated by a predetermined value from the relative phase locked by the locking mechanism, operates the locking mechanism at the convergence position, and then changes the relative phase through the relative phase locked by the locking mechanism. The valve timing control device for an internal combustion engine, wherein the lock mechanism performs locking by controlling to the above.

According to such a configuration, the lock mechanism is locked when passing through the relative phase of locking, and the lock mechanism can be more reliably locked.
(B) In the valve timing control device for an internal combustion engine according to claim (A),
When the operation amount of the actuator indicates the passage of the relative phase locked by the lock mechanism, and the actual relative position at that time is deviated from the relative phase locked by the lock mechanism, the intermediate phase is reached. A valve timing control device for an internal combustion engine, characterized in that it is determined that the engine is not locked.

According to such a configuration, in terms of control, when the relative phase that the lock mechanism locks has passed and should have been locked, if the relative phase detection result is not the lock position, the lock mechanism is not locked. It is assumed that the actual relative phase has changed following the control.
(C) In the valve timing control device for an internal combustion engine according to any one of claims 1 to 5,
A valve timing control device for an internal combustion engine, wherein it is determined whether or not the lock mechanism is locked to the predetermined intermediate phase after a predetermined time or more has elapsed since the operation of the lock mechanism.

  According to such a configuration, it is possible to avoid erroneous determination of the success or failure of the lock during the operation delay of the lock mechanism.

1 is a system configuration diagram of an internal combustion engine in an embodiment. Sectional drawing which shows a VTC (Variable valve Timing Control) mechanism. Sectional drawing which follows the AA line of FIG. Sectional drawing which follows the BB line of FIG. Sectional drawing similar to FIG. 3 which shows the operating state of the said VTC mechanism. The graph which shows the magnetic flux density-magnetic field characteristic of a hysteresis material. The partial expanded sectional view of FIG. FIG. 8 is a schematic diagram in which the component of FIG. 7 is developed linearly, and shows the flow of magnetic flux in the initial state (a) and when the hysteresis ring rotates (b). The figure which shows the structure of a gap sensor. The diagram which shows the correlation with a gap and a gap sensor output. The diagram which shows the correlation with the angle position of a camshaft, and a gap sensor output. The flowchart which shows control of the lock mechanism at the time of an engine stop. The time chart which shows the characteristic of the lock mechanism control. The flowchart which shows 1st Embodiment of the starting time control by lock success / failure determination. The flowchart which shows 2nd Embodiment of the control at the time of start by lock success / failure determination.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Internal combustion engine, 105 ... Intake valve, 113 ... Variable valve timing mechanism (VTC), 114 ... Engine control unit (ECU), 117 ... Crank angle sensor, 119 ... Water temperature sensor, 120 ... Crankshaft, 132 ... Cam sensor, 134 ... Camshaft, 303 ... Drive ring, 318 ... Intermediate rotating body, 351 ... Lock pin, 352 ... Pin hole, 353 ... Electromagnetic actuator

Claims (5)

A first rotating body that is pivotally supported by the camshaft, a second rotating body that is arranged coaxially with the first rotating body and rotates in synchronization with the crankshaft, and a set of the first rotating body and the second rotating body An assembling angle changing mechanism that continuously changes the attaching angle by an actuator, and changing the assembling angle makes the relative phase of the camshaft continuously variable with respect to the crankshaft. In a valve timing control device for an internal combustion engine comprising a lock mechanism that locks the relative phase to a predetermined intermediate phase by locking an assembly angle between the first rotary body and the second rotary body to a predetermined intermediate angle.
After the engine stop request is generated, the actuator is controlled toward the predetermined intermediate phase and the lock mechanism is operated.
The valve timing of the internal combustion engine, wherein the valve timing of the internal combustion engine is determined based on a correlation between an operation amount of the actuator after the operation of the lock mechanism and a detection result of the relative phase. Control device.   When the engine is not locked to the predetermined intermediate phase at the previous engine stop, the relative phase is set to the most retarded angle side at the start, and the engine control at the start is switched to the control corresponding to the most retarded angle state. The valve timing control apparatus for an internal combustion engine according to claim 1.   2. The valve timing control for an internal combustion engine according to claim 1, wherein when the engine is not locked to the predetermined intermediate phase at the previous engine stop, the actuator is controlled to be the predetermined intermediate phase at the start. apparatus.   The actuator and the lock mechanism are again controlled to lock the actuator to the predetermined intermediate phase when it is determined that the actuator is not locked to the predetermined intermediate phase. A valve timing control device for an internal combustion engine according to claim 1.   5. The apparatus according to claim 1, further comprising: a relative phase detection unit that can detect the relative phase at an arbitrary timing, and feedback-controlling the actuator based on a detection result of the relative phase detection unit. A valve timing control device for an internal combustion engine according to claim 1.

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