JP2005214168A - Variable valve control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve control device for an internal combustion engine having a first varying mechanism for varying the valve lift amount of an engine valve, a second varying mechanism for varying the center phase of an opening angle of the engine valve, and a throttle valve provided on the upstream side of an intake valve, suppressing the degradation of engine performance while avoiding mechanical inconveniences including interference due to troubles of the valve property varying mechanisms. <P>SOLUTION: A VEL (Variable valve Event and Lift) mechanism provided on the side of the intake valve and a VTC (Variable valve Timing Control) mechanism are used for controlling an intake air amount. When the VTC mechanism is troubled, a valve timing is forcibly driven to the slowest timing side and the intake air amount is controlled by the throttle valve. Besides, the maximum valve lift amount is set according to a trouble position of the valve timing, and the valve lift amount is increased in a range of the maximum valve lift amount or less when the required amount of gas passing through the intake valve is not obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a first variable mechanism that varies a valve lift amount of an engine valve, a second variable mechanism that varies a center phase of an operating angle of the engine valve, and a throttle valve provided upstream of the intake valve. The present invention relates to a variable valve control apparatus for an internal combustion engine comprising:

Patent Document 1 discloses an internal combustion engine that includes a valve lift adjustment mechanism that varies a valve lift amount of an engine valve by switching a cam and a valve timing adjustment mechanism that changes a phase of a camshaft relative to a crankshaft. There is a disclosure of a configuration in which when one of the two adjustment mechanisms fails, the valve lift adjustment mechanism is controlled to a low lift cam and the valve timing adjustment mechanism is controlled in a direction in which the center of the operating angle is away from the top dead center.
Japanese Patent Laid-Open No. 08-177434

  By the way, as described above, if the valve lift is reduced when the failure occurs and the center of the operating angle is retarded, mechanical inconveniences such as interference between the engine valve and the piston and interference between the intake valve and the exhaust valve occur. However, the amount of intake air of the engine is limited by reducing the valve lift amount of the intake valve, and the valve overlap is reduced and the charging efficiency to the cylinder is reduced in a high rotation range. There was a problem that the engine performance would be greatly limited.

  The present invention has been made in view of the above problems, and an internal combustion engine capable of suppressing deterioration of engine performance while avoiding occurrence of mechanical inconvenience such as interference due to failure of a variable mechanism of valve characteristics. An object of the present invention is to provide a variable valve control apparatus for an engine.

Therefore, in the first aspect of the present invention, the first variable mechanism that makes the valve lift amount of the intake valve variable, the second variable mechanism that makes the center phase of the operating angle of the intake valve variable, and the upstream side of the intake valve A variable valve control apparatus for an internal combustion engine comprising a throttle valve provided in the engine,
When the first and second variable mechanisms are normal, the intake air amount of the engine is controlled by the first and second variable mechanisms,
When one of the first variable mechanism and the second variable mechanism fails, the throttle valve controls the intake air amount of the engine and sets the operating range of the other variable mechanism according to the failure position, The other variable mechanism is controlled within the operating range.

  According to such a configuration, when one of the first variable mechanism and the second variable mechanism fails, the intake air amount of the engine is controlled by the throttle valve. On the other hand, for example, when the first variable mechanism fails, the first variable mechanism The operating range of the second variable mechanism (variable range of the central phase of the operating angle) is set according to the failure position of the mechanism (the valve lift amount in the failure state), and the second variable mechanism is controlled within the operating range. .

Therefore, even if one of the first variable mechanism and the second variable mechanism fails, the intake air amount can be controlled by the throttle valve, and mechanical inconvenience occurs even if the control of the normal variable mechanism is continued. Can be avoided.
The failure position includes not only a position determined by a failure mode such as a fixing failure of the first and second variable mechanisms but also a position determined by fail-safe processing for the failure.

According to a second aspect of the present invention, when the required intake air amount of the engine cannot be obtained in a state where one of the first variable mechanism and the second variable mechanism has failed, the required intake air amount within the operating range. The other variable mechanism is controlled so as to be close to.
According to this configuration, the amount of gas passing through the intake valve is limited due to a failure of either the first variable mechanism or the second variable mechanism, and the required intake air of the engine is controlled even if the throttle valve is controlled to open. When the amount cannot be obtained, the normal variable mechanism is controlled within the operation range corresponding to the other failure position, thereby increasing the intake air amount of the engine and obtaining the required intake air amount.

Therefore, even if one of the first and second variable mechanisms of the intake valve breaks down, it can be avoided that the intake air amount is greatly limited by the intake valve and the engine performance is greatly deteriorated, and the valve interference or the like can be avoided. The occurrence of mechanical inconvenience can be avoided.
According to a third aspect of the present invention, when the required passing gas amount and the actual passing gas amount in the intake valve are calculated, and when the actual passing gas amount is smaller than the required passing gas amount, the required passing gas amount is within the operating range. The other variable mechanism is controlled so as to approach the amount of passing gas.

According to such a configuration, the required value and actual value of the gas amount passing through the intake valve are calculated respectively, and when the actual passing gas amount is smaller than the required passing gas amount, for example, the valve lift amount and the operating angle The center phase is changed within a range corresponding to the failure position so as to approach the required passing gas amount.
Therefore, the control state required for the normal variable mechanism can be accurately determined when the intake air amount is limited by the intake valve due to the failure of the variable mechanism.

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 exhaust valve 107 is driven to open and close by a cam 111 pivotally supported on the exhaust side camshaft 110 while maintaining a constant valve lift, valve operating angle, and valve timing.
On the other hand, on the intake valve 105 side, a variable valve event and lift (VEL) mechanism 112 that continuously varies the valve lift amount of the intake valve 105 together with the operating angle is provided.
The VEL mechanism 112 corresponds to the first variable mechanism in the present embodiment.

Further, on the intake valve 105 side, a VTC (Variable Valve Timing Control) mechanism 113 that continuously varies the center phase of the valve operating angle of the intake valve 105 by changing the rotational phase of the intake camshaft with respect to the crankshaft. Is provided.
The VTC mechanism 113 corresponds to the second variable mechanism in the present embodiment.
An engine control unit (ECU) 114 incorporating a microcomputer controls the VEL mechanism 112 and the VTC mechanism 113 so as to obtain a required intake air amount, a required residual gas rate, etc. corresponding to the required torque, while receiving the required intake. The electronic control throttle 104 is controlled so as to obtain a negative pressure.

  The ECU 114 includes an air flow meter 115 that detects the intake air amount of the internal combustion engine 101, an accelerator pedal sensor 116 that detects the accelerator opening, a crank angle sensor 117 that extracts a crank rotation signal from the crankshaft 120, and an opening of the throttle valve 103b. Detection signals are input from a throttle sensor 118 that detects TVO and a water temperature sensor 119 that detects the coolant temperature of the internal combustion engine 101.

Further, an electromagnetic fuel injection valve 131 is provided in the intake port 130 upstream of the intake valve 105 of each cylinder. The fuel injection valve 131 is driven to open by the injection pulse signal from the ECU 114, and the injection is performed. An amount of fuel proportional to the injection pulse width (valve opening time) of the pulse signal is injected.
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 the cam bearing 14 of the cylinder head 11, and the cam shaft. Two eccentric cams 15 and 15 (drive cams), which are rotational cams supported by the shaft 13, a control shaft 16 rotatably supported by the same cam bearing 14 above the cam shaft 13, and the control shaft 16, a pair of rocker arms 18 and 18 supported by a control cam 17 so as to be swingable, and a pair of independent rockers disposed at upper ends of the intake valves 105 and 105 via valve lifters 19 and 19, respectively. The moving cams 20 and 20 are provided.

The eccentric cams 15 and 15 and the rocker arms 18 and 18 are linked by link arms 25 and 25, and the rocker arms 18 and 18 and the swing cams 20 and 20 are linked by link members 26 and 26.
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 the outer end surface of the cam main body 15a. A cam shaft insertion hole 15 c is formed through the shaft, and the shaft center X of the cam body 15 a is eccentric from the shaft center Y of the cam shaft 13 by a predetermined amount.
The eccentric cam 15 is press-fitted and fixed to the camshaft 13 on both outer sides that do not interfere with the valve lifter 19 via a camshaft insertion hole 15c.

As shown in FIG. 4, the rocker arm 18 is bent in a substantially crank shape, and a central base 18 a is rotatably supported by the control cam 17.
A pin hole 18d into which a pin 21 connected to the tip end of the link arm 25 is press-fitted is formed at one end 18b protruding from the outer end of the base 18a, while the inner end of the base 18a is formed. A pin hole 18e into which a pin 28 connected to one end portion 26a (described later) of each link member 26 is press-fitted is formed in the other end portion 18c projecting from the portion.

The control cam 17 has a cylindrical shape, is fixed to the outer periphery of the control shaft 16, and the position of the axis P1 is eccentric from the axis P2 of the control shaft 16 by α as shown in FIG.
As shown in FIGS. 2, 6, and 7, the rocking cam 20 has a substantially horizontal U shape, and a cam shaft 13 is fitted into a substantially annular base end portion 22 so as to be rotatably supported. A support hole 22a is formed through, and a pin hole 23a is formed through the end 23 located on the other end 18c side of the rocker arm 18.

Further, a base circle surface 24a on the base end portion 22 side and a cam surface 24b extending in an arc shape from the base circle surface 24a toward the end edge side of the end portion 23 are formed on the lower surface of the swing cam 20. The circular surface 24 a and the cam surface 24 b come into contact with predetermined positions on the upper surfaces of the valve lifters 19 in accordance with the swing position of the swing cam 20.
That is, when viewed from the valve lift characteristics shown in FIG. 8, as shown in FIG. 2, the predetermined angle range θ1 of the base circle surface 24a becomes the base circle section, and the predetermined angle range θ2 from the base circle section θ1 of the cam surface 24b changes. 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.

The link arm 25 includes an annular base portion 25a and a projecting end 25b projecting at a predetermined position on the outer peripheral surface of the base portion 25a. At the center position of the base portion 25a, the cam body of the eccentric cam 15 is provided. A fitting hole 25c is formed in the outer peripheral surface of 15a so as to be freely rotatable, and a pin hole 25d through which the pin 21 is rotatably inserted is formed in the protruding end 25b.
Further, the link member 26 is formed in a straight line having a predetermined length, and circular pin ends 26a and 26b have pin holes 18d in the other end 18c of the rocker arm 18 and the end 23 of the swing cam 20, respectively. , 23a, and pin insertion holes 26c and 26d through which end portions of the pins 28 and 29 are rotatably inserted are formed.

In addition, snap rings 30, 31, and 32 that restrict the axial movement of the link arm 25 and the link member 26 are provided at one end of each pin 21, 28, and 29.
In the above configuration, the valve lift amount changes as shown in FIGS. 6 and 7 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.

  The control shaft 16 is configured to be rotationally driven by a DC servo motor (actuator) 121 within a predetermined rotational angle range limited by a stopper with the configuration shown in FIG. Is changed by the actuator 121 so that the valve lift amount and the valve operating angle of the intake valve 105 continuously change within a variable range between the maximum valve lift amount and the minimum valve lift amount limited by the stopper. (See FIG. 9).

In FIG. 10, the DC servo motor 121 is arranged so that its rotation shaft is parallel to the control shaft 16, and a bevel gear 122 is pivotally supported at the tip of the rotation shaft.
On the other hand, a pair of stays 123a and 123b are fixed to the tip of the control shaft 16, and a nut 124 is swingably supported around an axis parallel to the control shaft 16 connecting the tips of the pair of stays 123a and 123b. The

A bevel gear 126 meshed with the bevel gear 122 is pivotally supported at the tip of the screw rod 125 meshed with the nut 124, and the screw rod 125 is rotated by the rotation of the DC servo motor 121. The position of the nut 124 that meshes with the 125 is displaced in the axial direction of the screw rod 125 so that the control shaft 16 is rotated.
Here, the direction in which the position of the nut 124 is brought closer to the bevel gear 126 is a direction in which the valve lift amount is reduced, and conversely, the direction in which the position of the nut 124 is moved away from the bevel gear 126 is a direction in which the valve lift amount is increased. ing.

As shown in FIG. 10, a potentiometer type angle sensor 127 for detecting the angle of the control shaft 16 is provided at the tip of the control shaft 16, and the actual angle detected by the angle sensor 127 is the target angle. The ECU 114 feedback-controls the DC servo motor 121 so as to match (a target valve lift amount equivalent value).
In addition, the stopper member 128 protruding from the outer periphery of the control shaft 16 abuts on a receiving member (not shown) on the fixed side in both the increasing direction and decreasing direction of the valve lift, thereby rotating the control shaft 16. The range is regulated so that the minimum valve lift amount and the maximum valve lift amount are defined.

Next, the configuration of the VTC mechanism 113 will be described with reference to FIG.
The VTC mechanism 113 in this embodiment is a vane type variable valve timing mechanism, and is connected to a cam sprocket 51 (timing sprocket) that is driven to rotate by a crankshaft 120 via a timing chain, and an end portion of the intake camshaft 13. A rotating member 53 that is fixed and rotatably accommodated in the cam sprocket 51, a hydraulic circuit 54 that rotates the rotating member 53 relative to the cam sprocket 51, and a relative relationship between the cam sprocket 51 and the rotating member 53. And a lock mechanism 60 that selectively locks the rotational position at a predetermined position.

The cam sprocket 51 includes a rotating part (not shown) having a tooth part meshed with a timing chain (or timing belt) on the outer periphery, and a housing that is disposed in front of the rotating part and rotatably accommodates the rotating member 53. 56, and a front cover and a rear cover (not shown) for closing the front and rear openings of the housing 56.
The housing 56 has a cylindrical shape with openings at the front and rear ends, and has a trapezoidal shape in cross section on the inner peripheral surface, and four partition walls 63 provided along the axial direction of the housing 56 are spaced by 90 °. It is projecting at.

The rotating member 53 is fixed to the front end portion of the intake side camshaft 14, and four vanes 78 a, 78 b, 78 c, 78 d are provided on the outer peripheral surface of the annular base 77 at 90 ° intervals.
Each of the first to fourth vanes 78a to 78d has a substantially inverted trapezoidal cross section, and is disposed in a recess between the partition walls 63. The recesses are separated from each other in the rotational direction, and the vanes 78a to 78d. An advance side hydraulic chamber 82 and a retard side hydraulic chamber 83 are formed between both sides and both side surfaces of each partition wall 63.

The lock mechanism 60 is configured such that the lock pin 84 engages with an engagement hole (not shown) at the rotation position (reference operation state) on the maximum retard angle side of the rotation member 53.
The hydraulic circuit 54 includes two systems, a first hydraulic passage 91 that supplies and discharges hydraulic pressure to the advance side hydraulic chamber 82 and a second hydraulic passage 92 that supplies and discharges hydraulic pressure to the retard side hydraulic chamber 83. These hydraulic passages 91 and 92 are connected to a supply passage 93 and drain passages 94a and 94b through passage switching electromagnetic switching valves 95, respectively.

The supply passage 93 is provided with an engine-driven oil pump 97 that pumps oil in the oil pan 96, while the downstream ends of the drain passages 94 a and 94 b communicate with the oil pan 96.
The first hydraulic passage 91 is connected to four branch passages 91 d that are formed substantially radially in the base 77 of the rotating member 53 and communicate with the advance-side hydraulic chambers 82. It is connected to four oil holes 92 d that open to the retard side hydraulic chamber 83.

The electromagnetic switching valve 95 is configured such that an internal spool valve body relatively switches and controls the hydraulic passages 91 and 92, the supply passage 93, and the drain passages 94a and 94b.
The ECU 114 controls the energization amount for the electromagnetic actuator 99 that drives the electromagnetic switching valve 95 based on a duty control signal on which a dither signal is superimposed.
For example, when a control signal (OFF signal) with a duty ratio of 0% is output to the electromagnetic actuator 99, the hydraulic oil pressure-fed from the oil pump 47 is supplied to the retard-side hydraulic chamber 83 through the second hydraulic passage 92. At the same time, the hydraulic oil in the advance side hydraulic chamber 82 is discharged from the first drain passage 94 a into the oil pan 96 through the first hydraulic passage 91.

Therefore, the internal pressure of the retard side hydraulic chamber 83 is high and the internal pressure of the advance side hydraulic chamber 82 is low, and the rotating member 53 rotates to the maximum retard side via the vanes 78a to 78b. The opening period (opening timing and closing timing) of the intake valve 105 is delayed.
On the other hand, when a control signal (ON signal) with a duty ratio of 100% is output to the electromagnetic actuator 99, the hydraulic oil is supplied into the advance side hydraulic chamber 82 through the first hydraulic passage 91 and the retard side hydraulic pressure is supplied. The hydraulic oil in the chamber 83 is discharged to the oil pan 96 through the second hydraulic passage 92 and the second drain passage 94b, and the retard side hydraulic chamber 83 becomes low pressure.

For this reason, the rotating member 53 rotates to the maximum advance side via the vanes 78a to 78d, and thereby the opening period (opening timing and closing timing) of the intake valve 105 is advanced.
As described above, the ECU 114 controls the VEL mechanism 112 and the VTC mechanism 113 so as to obtain a required intake air amount, a required residual gas rate, and the like, and diagnoses a failure of the VEL mechanism 112 and the VTC mechanism 113. A function of controlling the electronic control throttle 104, the VEL mechanism 112, and the VTC mechanism 113 is provided so as to avoid a significant decrease in engine performance even when a failure occurs.

Hereinafter, the control at the time of the failure will be described in detail according to the flowcharts of FIGS.
The flowchart of FIG. 12 shows the control when the VTC mechanism 113 fails.
First, in step S1, failure diagnosis of the VTC mechanism 113 is performed.
In the failure diagnosis of the VTC mechanism 113, for example, when a state where the deviation between the actual valve timing and the target is a predetermined value or more continues for a predetermined time or more, the failure of the VTC mechanism 113 is determined.

In step S2, it is determined whether or not the VTC mechanism 113 has failed.
If the VTC mechanism 113 is out of order, the process proceeds to step S3, and a control signal (OFF signal) with a duty ratio of 0% is forcibly output to the electromagnetic actuator 99 of the VTC mechanism 113, thereby controlling the valve of the intake valve 105. Forcibly drive the timing to the maximum retarded angle side.
In step S3, the electronic control throttle 104 is controlled in accordance with the accelerator opening so that the intake air amount of the engine is controlled by the throttle valve 103b.

In other words, in the normal state, the intake air amount is controlled by the VEL mechanism 112 and the VTC mechanism 113, and the electronic control throttle 104 is controlled to have a constant negative suction pressure. However, if the VTC mechanism 113 fails, the throttle opening degree The intake air amount of the engine is adjusted by the control.
In step S4, the required torque is calculated from the accelerator opening and the engine rotational speed Ne.

In step S5, the required torque is converted into a required volume flow rate based on the engine rotational speed, and the required volume flow rate is corrected by the upstream pressure (intake pressure) of the intake valve 105, etc. Convert to valve passing gas amount.
In step S6, the actual intake valve passing gas amount is calculated from the valve lift amount (opening area) of the intake valve 105, the engine speed, the upstream pressure (intake pressure) of the intake valve 105, and the closing timing of the intake valve 105 at that time. To do.

In step S7, it is determined whether or not the actual intake valve passage gas amount is smaller than the required intake valve passage gas amount.
If the actual intake valve passage gas amount is smaller than the required intake valve passage gas amount, the process proceeds to step S8.
In step S8, the valve timing of the intake valve 105 at that time, that is, the valve timing (failure position) of the intake valve 105 when the VTC mechanism 113 fails is detected.

In step S3, the VTC mechanism 113 is forcibly driven to the maximum retarded angle side. However, when there is a sticking failure, the actual valve timing may not be at the maximum retarded position. The valve timing (failure position) is detected again.
If the sensor for detecting the valve timing has failed, it is assumed that the valve timing is at the maximum retard position in step S8.

In step S9, at the valve timing (failure position) of the intake valve 105 in the failure state of the VTC mechanism 113, the intake valve 105 and the piston do not interfere with each other even if the piston reaches top dead center. Set the valve lift.
In step S10, control is performed so that the valve lift amount of the intake valve 105 is increased within the maximum valve lift amount so that the actual intake valve passage gas amount increases and approaches the required intake valve passage gas amount. .

Thus, when the valve timing cannot be adjusted due to a failure of the VTC mechanism 113 and the required valve passage gas amount cannot be obtained, the valve is within a range in which interference between the intake valve 105 and the piston does not occur. Increase the amount of gas passing through the valve by increasing the lift amount.
Therefore, even if the valve timing of the intake valve 105 is fixed on the advance side, the valve lift amount of the intake valve 105 is adjusted while avoiding interference between the intake valve 105 and the piston, and the required valve passing gas amount The engine performance at the time of failure can be avoided.

The flowchart of FIG. 13 shows control when the VEL mechanism 112 fails.
First, in step S21, failure diagnosis of the VEL mechanism 112 is performed.
In the failure diagnosis of the VEL mechanism 112, for example, a failure of the VEL mechanism 112 is determined when a state where the deviation between the actual valve lift amount (angle of the control shaft 16) and the target is a predetermined value or more continues for a predetermined time or more. To do.

In step S22, it is determined whether or not the VEL mechanism 112 has failed.
If the VEL mechanism 112 has failed, the process proceeds to step S23, and the driving of the DC servo motor 121 that rotationally drives the control shaft 16 of the VEL mechanism 112 is stopped.
In step S23, the electronic control throttle 104 is controlled in accordance with the accelerator opening, so that the engine intake air amount is controlled by the throttle valve 103b.

In steps S24 to S26, the required intake valve passage gas amount and the actual intake valve passage gas amount are calculated in the same manner as in steps S4 to S6.
In step S27, it is determined whether or not the actual intake valve passage gas amount is smaller than the required intake valve passage gas amount.
If the actual intake valve passage gas amount is smaller than the required intake valve passage gas amount, the process proceeds to step S28.

In step S28, the valve lift (failure position) of the intake valve 105 at that time is detected.
In step S29, in the valve lift amount of the intake valve 105 in the failure state, the maximum advance amount of valve timing is set so that the intake valve 105 and the piston do not interfere even if the piston reaches top dead center. .

In step S30, the valve timing of the intake valve 105 is controlled to be equal to or less than the maximum advance amount so as to increase the actual intake valve passage gas amount and to be close to the required intake valve passage gas amount.
Thus, when the valve lift amount cannot be adjusted due to a failure of the VEL mechanism 112 and the required valve passage gas amount cannot be obtained, the interference between the intake valve 105 and the piston does not occur. Adjust the valve timing to increase the amount of gas passing through the valve.

Therefore, even if the valve lift amount of the intake valve 105 is fixed on the high lift side, the valve timing of the intake valve 105 is adjusted while avoiding interference between the intake valve 105 and the piston, and the required valve passing gas amount. The engine performance at the time of failure can be avoided.
When one of the VEL mechanism 112 and the VTC mechanism 113 fails and the state in which the amount of gas passing through the intake valve is larger than required cannot be resolved by the control of the throttle valve, the normal variable mechanism is in a range corresponding to the failure position. It is also possible to reduce the amount of gas passing through the intake valve by controlling the inside.

1 is a system configuration diagram of an internal combustion engine in an embodiment. Sectional drawing which shows a VEL (Variable valve Event and Lift) mechanism (AA sectional drawing of FIG. 3). The side view of the said VEL mechanism. The top view of the said VEL mechanism. The perspective view which shows the eccentric cam used for the said VEL mechanism. Sectional drawing which shows the effect | action at the time of the low lift of the said VEL mechanism (BB sectional drawing of FIG. 3). Sectional drawing which shows the effect | action at the time of the high lift of the said VEL mechanism (BB sectional drawing of FIG. 3). The valve lift characteristic view corresponding to the base end surface and cam surface of the swing cam in the VEL mechanism. FIG. 6 is a characteristic diagram of valve timing and valve lift of the VEL mechanism. The perspective view which shows the rotational drive mechanism of the control shaft in the said VEL mechanism. The longitudinal cross-sectional view which shows a VTC (Variable valve Timing Control) mechanism. The flowchart which shows the control at the time of the failure of the said VTC mechanism. The flowchart which shows the control at the time of the failure of the said VEL mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 16 ... Control shaft, 101 ... Internal combustion engine, 104 ... Electronically controlled throttle, 105 ... Intake valve, 107 ... Exhaust valve, 112 ... VEL mechanism (variable valve mechanism), 113 ... VTC mechanism (variable valve timing mechanism), 114 ... Engine control unit (ECU), 121 ... DC servo motor, 127 ... Angle sensor

Claims (3)

A first variable mechanism that varies a valve lift amount of the intake valve; a second variable mechanism that varies a center phase of an operating angle of the intake valve; and a throttle valve provided upstream of the intake valve. A variable valve controller for an internal combustion engine,
When the first and second variable mechanisms are normal, the intake air amount of the engine is controlled by the first and second variable mechanisms,
When one of the first variable mechanism and the second variable mechanism fails, the throttle valve controls the intake air amount of the engine and sets the operating range of the other variable mechanism according to the failure position, A variable valve controller for an internal combustion engine that controls the other variable mechanism within the operating range.   When the required intake air amount of the engine cannot be obtained in a state where either one of the first variable mechanism or the second variable mechanism fails, the other variable mechanism is brought close to the required intake air amount within the operating range. The variable valve control apparatus for an internal combustion engine according to claim 1, wherein:   The required passing gas amount and the actual passing gas amount in the intake valve are calculated, and when the actual passing gas amount is smaller than the required passing gas amount, the approaching gas amount approaches the required passing gas amount within the operating range. The variable valve control apparatus for an internal combustion engine according to claim 2, wherein the other variable mechanism is controlled.

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