JP2004162662A - Control device for variable valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a restartability in an engine provided with a variable valve mechanism to change lift quantity of an intake valve capable of avoiding engine failure in quick deceleration with large lift quantity due to response delay of lift quantity control so as to secure restartability. <P>SOLUTION: When change quantity ΔNe per unit time for engine speed Ne (rpm) is more than a prescribed value, a quick speed reduction state is determined. In quick speed reduction, the maximum limiter to limit target lift quantity is set smaller as ΔNe is larger for changing the target lift quantity to be smaller. Reduction change speed of lift quantity by feedback control is thus increased, thereby response delay of the lift quantity change is reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a variable valve mechanism that changes a lift amount of an engine valve (an intake valve, an exhaust valve) provided in an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a variable valve mechanism configured to continuously change a valve lift amount of an engine valve with a change in a valve operating angle (see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2001-012262
[Problems to be solved by the invention]
By the way, in the variable valve mechanism that changes the lift amount of the engine valve as described above, the lift amount is generally controlled to be high in the high rotation range of the engine, but the engine rotation rapidly decreases from the high lift state. If an abnormal state occurs in which the engine stalls as it is, the engine may stall before changing to a low lift amount suitable for a low rotation range due to a response delay of a change in the lift amount.
[0005]
In the variable valve mechanism, since the lift amount cannot be changed when the engine is stopped, the restart is performed in a state where the lift amount is larger than usual.
[0006]
However, when the lift amount of the engine valve is large, the friction of the variable valve mechanism becomes large. Therefore, when restarting in a state where the lift amount is large, a large starting torque is required, and a problem that the startability is deteriorated. Occurs.
[0007]
The present invention has been made in view of the above problems, and even if an abnormal state occurs in which the engine speed suddenly decreases from a high rotation range and stalls as it is, the lift amount of the engine valve can be minimized, An object is to ensure startability at restart.
[0008]
[Means for Solving the Problems]
Therefore, according to the first aspect of the invention, the speed of change of the lift amount is increased and corrected in accordance with the deceleration during the deceleration operation.
[0009]
According to the above configuration, in a state where the lift amount is to be reduced and changed in association with the deceleration operation, the change speed of the lift amount is increased and corrected in accordance with the deceleration, so that the response delay to the lift amount change request is reduced.
[0010]
Therefore, even during rapid deceleration, it is possible to prevent the engine from stopping in a state where the lift amount is large, and thus it is possible to ensure the startability at the time of restart.
According to the second aspect of the present invention, the maximum change rate of the lift amount is corrected by changing the maximum limiter of the lift amount according to the deceleration.
[0011]
According to the above configuration, by changing the maximum limit of the lift amount during deceleration, the target lift amount corresponding to the rotation speed at that time is limited by the maximum limiter and changed to a smaller target lift amount.
[0012]
Therefore, as compared with the case where the variable valve mechanism is feedback-controlled according to the target lift amount corresponding to the rotation speed at that time, the decrease change speed of the lift amount is corrected to be increased by an amount corresponding to the target being set smaller. .
[0013]
According to the third aspect of the present invention, the speed of change in the lift amount is increased and corrected by changing the control gain of the lift amount in accordance with the deceleration.
According to the above configuration, the control gain for changing the actual lift amount to follow the target lift amount during the deceleration operation is changed according to the deceleration.
[0014]
Therefore, by increasing and correcting the control gain at the time of sudden deceleration, the response delay with respect to the target lift amount is reduced, and the change speed of the lift amount is increased and corrected.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a system configuration diagram of a vehicle internal combustion engine provided with a variable valve mechanism.
[0016]
1, an electronic control throttle 104 for opening and closing a throttle valve 103b by a throttle motor 103a is interposed in an intake pipe 102 of an internal combustion engine 101, and a combustion chamber 106 is provided via the electronic control throttle 104 and an intake valve 105. Air is sucked into the interior.
[0017]
The combustion exhaust gas is exhausted from the combustion chamber 106 via an exhaust valve 107, purified by a front catalyst 108 and a rear catalyst 109, and then released into the atmosphere.
The exhaust valve 107 is opened and closed by a cam 111 supported by an exhaust camshaft 110 at a constant valve lift and a valve operating angle.
[0018]
On the other hand, the intake valve 105 is provided with a variable valve event and lift (VEL) mechanism 112 that continuously and variably controls the valve lift amount together with the operating angle as a variable valve operating mechanism.
[0019]
The intake valve 105 may be provided with a variable valve timing mechanism for changing the valve timing by changing the phase of the operating angle with respect to the crank angle together with the VEL mechanism 112. A configuration in which a variable valve mechanism is provided may be used.
[0020]
An engine control unit (ECU) 114 containing a microcomputer controls the electronic control throttle 104 and the VEL mechanism 112 according to the engine operating state (for example, accelerator opening and engine speed).
[0021]
The ECU 114 includes an air flow meter 115 for detecting an intake air amount Q of the engine 101, an accelerator pedal sensor APS 116 for detecting an amount of depression of an accelerator pedal, and a crank for extracting a reference crank angle signal Ref for each crank angle 180 ° from the crank shaft 120. Detection signals are input from an angle sensor 117, a throttle sensor 118 for detecting an opening TVO of the throttle valve 103b, and a vehicle speed sensor 119 for detecting a vehicle speed VSP.
[0022]
In addition, an electromagnetic fuel injection valve 131 is provided at the intake port 130 on the upstream side of the intake valve 105 of each cylinder. When the fuel injection valve 131 is driven to open by an injection pulse signal from the ECU 114, Fuel is injected in an amount proportional to the injection pulse width (valve opening time).
[0023]
2 to 4 show the structure of the VEL mechanism 112 in detail.
The VEL mechanism 112 shown in FIGS. 2 to 4 includes a pair of intake valves 105, 105, a hollow cam shaft 13 (drive shaft) rotatably supported by a cam bearing 14 of the cylinder head 11, and the cam shaft. 13, two eccentric cams 15 and 15 (drive cams), which are rotatable cams, a control shaft 16 rotatably supported by the same cam bearing 14 above the cam shaft 13, and a control shaft 16 A pair of rocker arms 18, 18 rotatably supported by a control cam 16 via a control cam 17, and a pair of independent rockers arranged at the upper ends of the intake valves 105, 105 via valve lifters 19, 19. Moving cams 20 and 20 are provided.
[0024]
The eccentric cams 15, 15 and the rocker arms 18, 18 are linked by link arms 25, 25, and the rocker arms 18, 18 and the swing cams 20, 20 are linked by link members 26, 26.
[0025]
The rocker arms 18, 18, the link arms 25, 25, and the link members 26, 26 constitute a transmission mechanism.
As shown in FIG. 5, the eccentric cam 15 has a substantially ring shape and includes a small-diameter cam main body 15a and a flange portion 15b integrally provided on an outer end surface of the cam main body 15a. The camshaft insertion hole 15c is formed therethrough, and the axis X of the cam body 15a is eccentric from the axis Y of the camshaft 13 by a predetermined amount.
[0026]
Further, the eccentric cam 15 is press-fitted and fixed to both sides of the cam shaft 13 which do not interfere with the valve lifter 19 via the cam shaft insertion holes 15c.
As shown in FIG. 4, the rocker arm 18 is bent substantially in a crank shape, and a central base 18a is rotatably supported by the control cam 17.
[0027]
A pin hole 18d into which the pin 21 connected to the distal end of the link arm 25 is press-fitted is formed through one end 18b protruding from the outer end of the base 18a, while the inner end of the base 18a is formed. The other end portion 18c protruding from the portion has a pin hole 18e into which a pin 28 connected to one end portion 26a of each link member 26 described later is press-fitted.
[0028]
The control cam 17 has a cylindrical shape and is fixed to the outer periphery of the control shaft 16, and the position of the axis P 1 is eccentric from the axis P 2 of the control shaft 16 by α as shown in FIG.
[0029]
The swing cam 20 has a substantially horizontal U-shape as shown in FIGS. 2, 6, and 7, and the cam shaft 13 is fitted into a substantially annular base end portion 22 and is rotatably supported. A support hole 22a is formed to penetrate, and a pin hole 23a is formed to penetrate an end 23 located on the other end 18c side of the rocker arm 18.
[0030]
On the lower surface of the swing cam 20, a base circular surface 24a on the base end portion 22 side and a cam surface 24b extending in an arc from the base circular surface 24a to the end edge side of the end portion 23 are formed. The circular surface 24a and the cam surface 24b abut on a predetermined position on the upper surface of each valve lifter 19 according to the swing position of the swing cam 20.
[0031]
That is, from the viewpoint of the valve lift characteristics shown in FIG. 8, the predetermined angle range θ1 of the base circle surface 24a becomes the base circle section as shown in FIG. 2, and the predetermined angle range θ2 from the base circle section θ1 of the cam surface 24b. This is a so-called ramp section, and further, a predetermined angle range θ3 from the ramp section θ2 of the cam surface 24b is set to be a lift section.
[0032]
The link arm 25 includes an annular base 25a and a protruding end 25b protruding at a predetermined position on the outer peripheral surface of the base 25a. The cam body of the eccentric cam 15 is provided at a central position of the base 25a. A fitting hole 25c rotatably fitted to the outer peripheral surface of 15a is formed, and a pin hole 25d through which the pin 21 is rotatably inserted is formed through the protruding end 25b.
[0033]
Further, the link member 26 is formed in a linear shape with a predetermined length, and the pin holes 18d of the other end 18c of the rocker arm 18 and the end 23 of the swing cam 20 are formed at both ends 26a and 26b of the circular shape. , 23a are respectively formed with pin insertion holes 26c, 26d through which the ends of the pins 28, 29, which are press-fitted, are rotatably inserted.
[0034]
At one end of each of the pins 21, 28, and 29, snap rings 30, 31, and 32 that regulate the axial movement of the link arm 25 and the link member 26 are provided.
[0035]
In the above configuration, as shown in FIGS. 6 and 7, the valve lift varies depending on the positional relationship between the axis P2 of the control shaft 16 and the axis P1 of the control cam 17, and the control shaft 16 is rotated. By driving, the position of the axis P2 of the control shaft 16 with respect to the axis P1 of the control cam 17 is changed.
[0036]
The control shaft 16 is configured to be rotationally driven within a predetermined rotation angle range by a DC servomotor (actuator) 121 by a configuration as shown in FIG. , The valve lift amount and the valve operating angle of the intake valve 105 continuously change (see FIG. 9).
[0037]
In FIG. 10, the DC servo motor 121 is arranged so that its rotation axis is parallel to the control shaft 16, and a bevel gear 122 is supported at the tip of the rotation shaft. On the other hand, a pair of stays 123a and 123b are fixed to the distal end of the control shaft 16, and a nut 124 is swingably supported around an axis parallel to the control shaft 16 connecting the distal ends of the pair of stays 123a and 123b. You.
[0038]
A bevel gear 126 meshed with the bevel gear 122 is rotatably supported at the tip of a threaded rod 125 meshed with the nut 124. The rotation of the DC servomotor 121 causes the threaded rod 125 to rotate. The position of the nut 124 meshing with the shaft 125 is displaced in the axial direction of the screw rod 125, so that the control shaft 16 is rotated.
[0039]
Here, the direction in which the position of the nut 124 approaches the bevel gear 126 is a direction in which the valve lift amount decreases, and conversely, the direction in which the position of the nut 124 is away from the bevel gear 126 is a direction in which the valve lift amount increases. ing.
[0040]
As shown in FIG. 10, a potentiometer-type operating angle sensor 127 for detecting the operating angle of the control shaft 16 is provided at the tip of the control shaft 16, and the ECU 114 detects the operating angle of the control shaft 16 with the operating angle sensor 127. The DC servomotor 121 is feedback-controlled so that the actual operating angle matches a target operating angle (target lift amount) set based on, for example, the accelerator opening and the engine speed.
[0041]
In addition, basically, the target operation angle is set such that the lift amount increases as the rotation speed increases.
Further, the ECU 114 corrects the speed of change of the lift amount during the rapid deceleration operation by increasing the speed so that even if the engine stalls, the restart is not performed in a state where the lift amount is large. , The control as shown in the flowcharts of FIGS.
[0042]
The flowchart of FIG. 11 shows a routine for measuring the engine speed (engine speed) Ne.
The routine for calculating the engine speed Ne is executed every time the reference crank angle signal Ref is output from the crank angle sensor 117. In step S101, the cycle T of the reference crank angle signal Ref is read.
[0043]
In step S102, the engine speed Ne (rpm) is calculated based on the cycle T.
The flowchart in FIG. 12 shows a routine for setting the maximum limiter of the target lift amount (periodic processing routine) that is executed every fixed time (for example, 10 ms).
[0044]
In step S201, the amount of change ΔNe of the engine speed Ne per execution cycle of this routine is measured.
Details of step S201 are shown in the flowchart of FIG.
[0045]
In step S211, a deviation ΔNe between the engine speed Nez before the predetermined time and the latest value of the engine speed Ne is calculated.
ΔNe = Nez−Ne
In the next step S212, the latest engine speed Ne is updated and stored as Nez for the next ΔNe calculation.
[0046]
In the flowchart of FIG. 12, when ΔNe is measured in step S201, a rapid deceleration determination is performed in the next step S202.
Details of the sudden deceleration determination in step S202 are shown in the flowchart of FIG.
[0047]
In step S221, by comparing ΔNe indicating the deceleration of the engine speed with a predetermined value (> 0), it is determined whether or not the engine speed Ne has decreased at a speed higher than a predetermined speed (the deceleration above a predetermined speed). Is determined).
[0048]
If it is determined in step S221 that ΔNe> predetermined value, the process proceeds to step S222, and 1 is set to the rapid deceleration determination flag fKG.
On the other hand, when it is determined in step S221 that ΔNe ≦ predetermined value, the process proceeds to step S223, and 0 is set in the rapid deceleration determination flag fKG.
[0049]
In the flowchart of FIG. 12, after the sudden deceleration determination in step S202, the process proceeds to step S203, in which a maximum limiter for limiting the target lift amount in the VEL mechanism 112 is set.
[0050]
Details of the setting of the maximum limiter in step S203 are shown in the flowchart of FIG.
In step S231, it is determined whether or not the rapid deceleration determination flag fKG is 1, that is, whether or not the vehicle is in a rapid deceleration operation that is equal to or more than a predetermined speed.
[0051]
When the rapid deceleration determination flag fKG is 1, the process proceeds to step S232, and the maximum lift amount limiter is set according to the ΔNe.
The maximum limiter is set to a smaller value as ΔNe is larger, in other words, as the vehicle is suddenly decelerated.
[0052]
When the target lift amount is larger than the maximum limiter, the maximum limiter is set as the target lift amount.
At the time of rapid deceleration, the target lift amount decreases and changes as the rotation decreases, but the actual lift amount is delayed with respect to the change in the target lift amount.
[0053]
Therefore, if the engine is suddenly decelerated and stalled, the actual lift amount is stalled with a higher value than the target, and the VEL mechanism 112 cannot change the lift amount when the engine is stopped. Therefore, when the engine is stopped, the lift amount is kept larger than it should be.
[0054]
In a state where the lift amount is large, the friction by the VEL mechanism 112 is large, and the startability is reduced.
Therefore, in the present embodiment, at the time of rapid deceleration, the target lift amount is forcibly made smaller than a value corresponding to the original rotation speed by the limitation by the maximum limiter, so that the target lift amount in feedback control of the lift amount and the actual lift amount are reduced. The deviation from the lift amount is increased to increase the speed at which the lift amount decreases.
[0055]
Therefore, even if the engine stalls as it is suddenly decelerated, the amount of lift at the time of engine stall can be reduced, and startability at the time of restart can be ensured, as compared with a case where no limit is imposed by the maximum limiter.
[0056]
Note that the maximum limiter does not need to be finely changed according to ΔNe, and may be configured to use a constant value at the time of sudden deceleration determination.
By the way, in the above-described embodiment, the target lift amount is limited to a smaller value by the maximum limiter of the lift amount at the time of rapid deceleration, so that the rate of decrease of the lift amount is increased. However, as shown in the flowchart of FIG. By changing the gain in the feedback control according to the deceleration (ΔNe), the speed at which the lift amount decreases can be increased.
[0057]
In the flowchart of FIG. 16, in step S301, ΔNe is measured in the same manner as in step S201.
In step S302, rapid deceleration determination is performed in the same manner as in step S202.
[0058]
In step S303, the control gain is set as shown in the flowchart of FIG.
In the flowchart of FIG. 17, in step S331, it is determined whether or not the rapid deceleration determination flag fKG is 1, that is, whether or not a rapid deceleration operation that is equal to or more than a predetermined speed is performed.
[0059]
When the rapid deceleration determination flag fKG is 1, the process proceeds to step S332, and the control gain of the lift amount is set according to the ΔNe.
The control gain is set to a larger value as the ΔNe becomes larger.
[0060]
As described above, if the control gain is increased during the rapid deceleration, the overshoot of the lift amount due to excessive gain during the normal deceleration is avoided, and the target lift amount during the rapid deceleration that may lead to engine stall is avoided. By delaying the response delay of the actual lift amount to the change, it is possible to prevent the engine from stopping in a state where the lift amount is large.
[0061]
Note that the control gain does not need to be finely changed according to ΔNe, and may be configured to use a constant value at the time of sudden deceleration determination.
Further, the change of the control gain includes forcibly outputting a predetermined control signal (for example, a maximum current signal) in the direction in which the lift amount decreases to the DC servo motor 121 during rapid deceleration.
[0062]
Further, in the above embodiment, the deceleration is determined from the variation ΔNe of the engine speed Ne per unit time. However, as shown in the flowcharts of FIGS. 18 to 23, the vehicle speed VSP is used instead of the ΔNe. , The amount of change ΔVSP is calculated, and the deceleration is determined based on the ΔVSP.
[0063]
FIG. 18 shows a routine for calculating the vehicle speed VSP with high accuracy.
The routine shown in the flowchart of FIG. 18 is executed every time a vehicle speed signal is output from the vehicle speed sensor 119.
[0064]
Then, first, in step S401, the generation cycle T of the vehicle speed signal is read.
In step S402, the vehicle speed VSP is calculated based on the cycle T.
On the other hand, the flowchart of FIG. 19 shows a routine for setting the maximum limiter (or control gain) of the lift amount executed at regular intervals (for example, 10 ms) (routine routine).
[0065]
In the flowchart of FIG. 19, in step S501, a change amount ΔVSP indicating the deceleration is measured.
The measurement of the ΔVSP is shown in detail in the flowchart of FIG.
[0066]
In the flowchart of FIG. 20, in step S511, ΔVSP is calculated as the deviation between the vehicle speed VSPz at the time of the previous execution of the routine shown in FIG. 19 and the latest vehicle speed VSP.
[0067]
ΔVSP = VSPz−VSP
In step S512, the latest vehicle speed VSP is set to the previous value VSPz for the next calculation of ΔVSP.
[0068]
In the flowchart of FIG. 19, in step S502, rapid deceleration determination is performed as shown in the flowchart of FIG.
In the flowchart of FIG. 21, in step S521, it is determined whether or not the ΔVSP is larger than a predetermined value.
[0069]
If ΔVSP is larger than the predetermined value, the process proceeds to step S522, and 1 is set to the rapid deceleration determination flag fKG. If ΔVSP is equal to or less than the predetermined value, the process proceeds to step S523, and the rapid deceleration determination flag fKG Is set to 0.
[0070]
In the flowchart of FIG. 19, in step S503, the maximum limiter of the lift amount or the control gain is set based on the sudden deceleration determination flag fKG. The flowchart of FIG. 22 shows the setting of the maximum limiter. In step S531, it is determined whether or not the rapid deceleration determination flag fKG is 1, and if fKG = 1, the process proceeds to step S532A.
[0071]
In step S532A, the larger the ΔVSP is, the smaller the maximum limiter is set.
On the other hand, the flowchart of FIG. 23 shows the setting of the control gain. In step S531, it is determined whether or not the rapid deceleration determination flag fKG is 1, and when fKG = 1, the process proceeds to step S532B.
[0072]
In step S532B, the larger the ΔVSP is, the larger the control gain is set.
In the above embodiment, the maximum limiter or the control gain is set from ΔNe or ΔVSP indicating the deceleration. However, the maximum limiter and the control gain are set from ΔNe or ΔVSP indicating the deceleration. At the time of sudden deceleration that may lead to, the target lift amount may be limited to a smaller value by the maximum limiter and the control gain may be increased.
[0073]
Further, in the sudden deceleration determination, the predetermined value to be compared with the aforementioned ΔNe or ΔVSP is changed according to the engine speed Ne and the vehicle speed VSP at that time, so that the lower the rotational speed and the lower the vehicle speed, the easier the rapid deceleration determination. good.
[0074]
Further, the variable valve mechanism for changing the valve lift amount is not limited to the above-described VEL mechanism 112. If the lift characteristics are difficult to change while the engine is stopped, the same control as in the above embodiment is performed. It is clear that the engine valve provided with the variable valve mechanism is not limited to the intake valve.
[0075]
Further, when the deviation between the target lift amount and the actual lift amount during the deceleration operation is equal to or greater than a predetermined value, or when the speed of increasing the deviation is equal to or more than a predetermined value, the larger the difference, or the faster the speed of increasing the difference. As the maximum limiter value decreases, the control gain may increase.
[0076]
Here, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects.
(A) The control device for a variable valve mechanism according to any one of claims 1 to 3, wherein the deceleration is determined based on an amount of change in the engine speed per unit time. Control device for variable valve mechanism.
[0077]
According to the above configuration, the deceleration is determined based on the amount of change in the engine speed per unit time, and the change speed of the lift amount is increased and corrected.
Therefore, when the engine rotational speed sharply decreases, the change speed of the lift amount is increased and corrected in accordance with the decrease in the rotational speed, and the response delay of the change in the lift amount is reduced, so that the engine stall with a large lift amount can be avoided. .
(B) The control device for a variable valve mechanism according to any one of claims 1 to 3, wherein the deceleration is determined based on an amount of change in vehicle speed per unit time. Mechanism control device.
[0078]
According to the above configuration, the deceleration is determined based on the change amount of the vehicle speed per unit time, and the change speed of the lift amount is increased and corrected.
Therefore, when the vehicle speed suddenly decreases, the change speed of the lift amount is increased and corrected in accordance with the decrease in the vehicle speed, and the response delay of the change in the lift amount is reduced, so that the engine stall with a large lift amount can be avoided.
(C) In the control device for a variable valve mechanism according to the above (a) or (b), the change amount of the engine speed per unit time or the change amount of the vehicle speed per unit time is compared with a predetermined value. A variable speed detecting means for determining whether or not the vehicle is suddenly decelerating, increasing and correcting the change speed of the lift amount at the time of sudden deceleration, and changing the predetermined value according to the engine speed or the vehicle speed. Control device for valve mechanism.
[0079]
According to the above configuration, by comparing the change amount per unit time of the engine rotation speed or the vehicle speed with a predetermined value, it is determined whether or not a sudden deceleration that causes a large delay in the change in the lift amount is performed. It is determined whether or not the change speed is to be increased, but by changing the predetermined value according to the engine speed or the vehicle speed, the change amount region in which the rapid deceleration determination is made for each speed range is changed.
[0080]
Therefore, while avoiding an excessive increase in the change speed of the lift amount in the high speed range, the rapid deceleration determination is appropriately performed in the low speed range where the possibility of engine stall is high, and the engine is stopped while the lift amount is high. Can be reliably avoided.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an internal combustion engine.
FIG. 2 is a sectional view showing a VEL mechanism (variable valve lift mechanism) (a sectional view taken along line AA in FIG. 3).
FIG. 3 is a side view of the VEL mechanism.
FIG. 4 is a plan view of the VEL mechanism.
FIG. 5 is a perspective view showing an eccentric cam used in the VEL mechanism.
FIG. 6 is a cross-sectional view (a cross-sectional view taken along the line BB in FIG. 3) illustrating the operation of the VEL mechanism during a low lift.
FIG. 7 is a cross-sectional view (a cross-sectional view taken along the line BB of FIG. 3) illustrating the operation of the VEL mechanism during a high lift.
FIG. 8 is a valve lift characteristic diagram corresponding to a base end surface and a cam surface of a swing cam in the VEL mechanism.
FIG. 9 is a characteristic diagram of valve timing and valve lift of the VEL mechanism.
FIG. 10 is a perspective view showing a rotation drive mechanism of a control shaft in the VEL mechanism.
FIG. 11 is a flowchart showing a routine for measuring the engine speed.
FIG. 12 is a flowchart showing a main routine for performing processing for setting a maximum limiter.
FIG. 13 is a flowchart showing a subroutine for measuring ΔNe.
FIG. 14 is a flowchart showing a subroutine for performing a sudden deceleration determination.
FIG. 15 is a flowchart showing a subroutine for setting a maximum limiter.
FIG. 16 is a flowchart showing a main routine for performing control gain setting processing.
FIG. 17 is a flowchart showing a subroutine for setting a control gain.
FIG. 18 is a flowchart illustrating a vehicle speed measurement routine.
FIG. 19 is a flowchart showing a main routine for setting a maximum limiter or a control gain based on ΔVSP.
FIG. 20 is a flowchart showing a subroutine for measuring ΔVSP.
FIG. 21 is a flowchart showing a subroutine for performing rapid deceleration determination based on ΔVSP.
FIG. 22 is a flowchart showing a subroutine for setting a maximum limiter based on ΔVSP.
FIG. 23 is a flowchart showing a subroutine for setting a control gain based on ΔVSP.
[Explanation of symbols]
101: internal combustion engine, 105: intake valve, 112: VEL mechanism, 114: engine control unit (ECU), 117: crank angle sensor, 119: vehicle speed sensor

Claims (3)

A control device for a variable valve mechanism that changes a lift amount of an engine valve,
A control device for a variable valve mechanism, wherein a change speed of the lift amount is increased and corrected according to a deceleration during a deceleration operation. The control device for a variable valve mechanism according to claim 1, wherein the change rate of the lift amount is increased and corrected by changing the maximum limiter of the lift amount according to the deceleration. 2. The control device for a variable valve mechanism according to claim 1, wherein a change speed of the lift amount is increased and corrected by changing a control gain of the lift amount according to deceleration.

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