JP4017297B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable valve operating apparatus for an internal combustion engine, and in particular, a variable valve operating system including a first variable mechanism that controls lift characteristics of an engine valve that is an intake valve or an exhaust valve, and a second variable mechanism that controls valve timing. Relates to the device.
[0002]
[Prior art]
As is well known, for example, a variable lift mechanism that makes the valve lift characteristic of the intake valve variable and a variable valve timing mechanism that makes the valve timing characteristic variable improve the degree of freedom of the valve lift characteristic and improve engine operating performance. Various variable valve actuating devices have been conventionally provided that greatly increase (see Japanese Patent Application Laid-Open No. 8-177434, etc.).
[0003]
In other words, this variable valve operating device selectively switches the low-speed cam and high-speed cam provided on the camshaft according to the engine operating state, and variably controls the cam lift of the intake valve or exhaust valve that is the engine valve. And a valve timing control mechanism that variably controls the opening / closing timing of the engine valve by converting the relative rotation phase of the camshaft and the crankshaft according to the engine operating state.
[0004]
Further, for example, when the valve timing control mechanism fails, this device forcibly switches to the low speed cam side by the valve lift control mechanism, or when the valve lift control mechanism fails, the valve timing control mechanism Controls the opening and closing timing of the engine valve by moving the valve lift operating center away from the top dead center Who A control mechanism for avoiding interference between the intake valve and the exhaust valve is provided by performing control in each direction.
[0005]
[Problems to be solved by the invention]
However, in the conventional variable valve device, when each control mechanism fails as described above, although mechanical inconvenience such as avoiding interference between the intake valve and the exhaust valve can be avoided, Consideration about engine performance at the time of such a failure was insufficient.
[0006]
In other words, when one of the control mechanisms fails, the valve lift control mechanism uniformly switches to the low speed cam, or the valve lift control mechanism moves the valve lift operation center uniformly away from the top dead center. Because of the control, the so-called valve overlap between the intake valve and the exhaust valve is necessarily reduced. Therefore, in the engine high-speed operation region, the output of the engine is greatly reduced, and it becomes difficult to sufficiently exhibit the engine performance.
[0007]
[Means for Solving the Problems]
The present invention has been devised in view of the actual situation of the conventional variable valve gear, and the invention according to claim 1 is characterized in that at least the lift characteristic of the engine valve is set according to the engine operating state. Continuously The first variable mechanism to be variably controlled and at least the opening / closing timing characteristics of the engine valve according to the engine operating state Continuously A second variable mechanism for variably controlling; a position detecting means for detecting a current operating position of the first variable mechanism or the second variable mechanism; and the first variable mechanism or the second variable mechanism based on a current engine operating state. When one of the first variable mechanism and the second variable mechanism fails, one of the variable target detected by the position detecting means when the control target value determining means determines the control target value of the first variable mechanism and the second variable mechanism. Based on the position, the control range of the other variable mechanism is set to a predetermined range, and the operating position of the other variable mechanism and the control target value determined by the detecting means within the set predetermined control range are determined. Control means for performing feedback control of the other variable mechanism continuously or stepwise based on the control target value determined by the means.
[0008]
According to this invention, for example, when the first variable mechanism fails in a predetermined operating region of the engine, the position detection means detects the position at the time of failure and outputs the information signal to the control means. As a result, the control means does not simply select and control the fixed low-speed cam by the first variable mechanism as in the prior art, but between the mechanical engine valves according to the position at the time of failure of the first variable mechanism. The second variable mechanism is controlled as much as possible within a predetermined range in which interference or the like can be avoided. Therefore, the engine performance can be exhibited as much as possible according to the engine operating state.
According to the second aspect of the present invention, at least the lift characteristic of the engine valve is determined according to the engine operating state. Continuous A first variable mechanism that is variably controlled, and at least an opening / closing timing characteristic of the engine valve according to an engine operating state Continuously A second variable mechanism for variably controlling; a first position detecting means for detecting a current operating position of the first variable mechanism; a second position detecting means for detecting a current operating position of the second variable mechanism; First control target value determining means for determining the control target value of the first variable mechanism based on the engine operating state, and the second position detecting means detected by the second position detecting means when the second variable mechanism fails. (2) The control range of the first variable mechanism is set to a predetermined control range based on the position at the time of failure of the variable mechanism, and the operation detected by the first position detection means within the set predetermined control range Control means for performing feedback control of the first variable mechanism continuously or stepwise based on the position and the control target value determined by the first control target value determining means is provided.
[0009]
According to the third aspect of the present invention, at least the lift characteristic of the engine valve is set according to the engine operating state. Continuously The first variable mechanism to be variably controlled and at least the opening / closing timing characteristics of the engine valve according to the engine operating state Continuously A second variable mechanism for variably controlling; a first position detecting means for detecting a current operating position of the first variable mechanism; a second position detecting means for detecting a current operating position of the second variable mechanism; Second control target value determining means for determining a control target value of the second variable mechanism based on the engine operating state, and a first detected by the first position detecting means when the first variable mechanism fails. The control range of the second variable mechanism is set to a predetermined control range based on the position at the time of failure of the one variable mechanism, and the operating position detected by the second position detection means within the set predetermined control range. And control means for performing feedback control of the second variable mechanism continuously or stepwise based on the control target value determined by the second control target value determining means.
[0010]
According to a fourth aspect of the present invention, the first variable mechanism has a drive shaft having a drive cam on the outer periphery, and a swing cam that is swingably supported by the support shaft and swings to open and close the engine valve. And a rocker arm whose one end is rotatably linked to the drive cam, the other end is rotatably linked to the swing cam, and the swing center is variably controlled by the control cam. It is a feature.
[0011]
According to a fifth aspect of the present invention, the first variable mechanism includes a drive shaft having a drive cam on the outer periphery, a link arm whose one end portion is rotatably linked to the outer periphery of the drive cam, and one end portion other than the link arm. A rocker arm that is rotatably linked to the end and whose swing center is variably controlled by a control cam, a swing cam that opens and closes an engine valve, and the swing cam and the other end of the rocker arm are mechanically rotated. A linkage member that freely links and regulates the maximum swing range of the swing cam within the swing range of the rocker arm, and an actuator that controls the rotation of the control cam via a control shaft according to the engine operating state. It is characterized by having.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment in which a variable valve device according to the present invention is applied to the intake side, and two intake valves 12 per cylinder, which are slidably provided on a cylinder head 11 via a valve guide (not shown), 12 and the variable valve lift of each intake valve 12, 12 is made variable according to the engine operation state, and the valve timing of each intake valve 12, 12 is made variable according to the engine operation state. The second variable mechanism 2 is provided.
[0013]
As shown in FIGS. 1 to 3, the first variable mechanism 1 includes a hollow drive shaft 13 that is rotatably supported by a bearing 14 at the top of the cylinder head 11, and is fixed to the drive shaft 13 by press fitting or the like. The flat lifts of the valve lifters 16 and 16 disposed at the upper end portions of the intake valves 12 and 12 are supported by the two drive cams 15 and 15 and the drive shaft 13 so as to be swingable. Rotating force of the drive cam 15 is linked between the swing cams 17 and 17 that are in sliding contact with the upper surfaces 16a and 16a to open the intake valves 12 and 12, and the drive cam 15 and the swing cams 17 and 17, respectively. Is transmitted as a swinging force of the swing cams 17, 17, and a control mechanism 19 that variably controls the operating position of the transfer mechanism 18 is provided.
[0014]
The drive shaft 13 is disposed along the longitudinal direction of the engine, and is connected to the crank of the engine via a timing chain (not shown) wound around a timing sprocket 40 of the variable mechanism 2 (described later) provided at one end. A rotational force is transmitted from the shaft.
[0015]
As shown in FIG. 1, the bearing 14 is provided at the upper end portion of the cylinder head 11, and is provided with a main bracket 14a that supports the upper portion of the drive shaft 13, and an upper end portion of the main bracket 14a. The sub bracket 14b rotatably supports the shaft 32, and both the brackets 14a and 14b are fastened together by a pair of bolts 14c and 14c from above.
[0016]
The drive cams 15 are substantially ring-shaped as shown in FIGS. 1 to 3, and are composed of a cam main body 15a and a cylindrical portion 15b integrally provided on the outer end surface of the cam main body 15a. A drive shaft insertion hole 15c is formed penetrating in the direction, and the axis X of the cam body 15a is offset from the axis Y of the drive shaft 13 by a predetermined amount in the radial direction. Each drive cam 15 is press-fitted and fixed to both sides of the drive shaft 13 through the drive shaft insertion hole 15c so as not to interfere with the valve lifters 16 and 16, and both the cam main bodies 15a and 15a are fixed. The outer peripheral surfaces 15d and 15d are formed in the same cam profile.
[0017]
As shown in FIG. 2, the swing cam 17 has a substantially U-shape, and a support hole in which a drive shaft 13 is fitted and inserted into an annular base end 20 on one end side so as to be rotatably supported. 20a is formed through, and a pin hole 21a is formed through the cam nose 21 at the other end. Further, a cam surface 22 is formed on the lower surface of the swing cam 17, and a base circle surface 22a on the base end portion 20 side, a ramp surface 22b extending from the base circle surface 22a to the cam nose portion 21 side in an arc shape, and the lamp A lift surface 22c is formed on the tip side of the surface 22b, and the base circle surface 22a, the ramp surface 22b, and the lift surface 22c correspond to the upper surface of each valve lifter 16 according to the swing position of the swing cam 17. 16a is in contact with a predetermined position.
[0018]
As shown in FIG. 2, the transmission mechanism 18 includes a rocker arm 23 disposed above the drive shaft 13, a link arm 24 that links the one end 23 a of the rocker arm 23 and the drive cam 15, and the other end of the rocker arm 23. A link rod 25 that is a linking member that links the portion 23b and the swing cam 17 is provided.
[0019]
As shown in FIG. 3, each of the rocker arms 23 is bent in a substantially crank shape when viewed from above, and a cylindrical base portion 23c at the center is rotatably supported by a control cam 33 described later. Further, as shown in FIGS. 2 and 3, a pin 26 is inserted into the one end portion 23a projecting from each outer end portion of each base portion 23c so as to be relatively rotatable with the link arm 24. While the holes 23d are formed so as to penetrate, the other end portions 23b projecting from the inner end portions of the respective base portions 23c are respectively provided with pins 27 that are rotatably connected to the one end portions 25a of the respective link rods 25. A pin hole 23e to be inserted is formed.
[0020]
The link arm 24 includes an annular base 24a having a relatively large diameter and a projecting end 24b projecting at a predetermined position on the outer peripheral surface of the base 24a. A fitting hole 24c is formed in the outer peripheral surface of the cam main body 15a of the cam 15 so as to be rotatably fitted. On the protruding end 24b, a pin hole 24d through which the pin 26 is rotatably inserted is formed. Yes.
[0021]
Further, as shown in FIG. 2, the link rod 25 is bent into a substantially rectangular shape having a predetermined length, and pin insertion holes 25c and 25d are formed at both ends 25a and 25b as shown in FIG. The pin insertion holes 25c and 25d are inserted into the pin holes 23e provided in the other end 23b of the rocker arm 23 and the pin holes 21a provided in the cam nose 21 of the swing cam 17, respectively. , 28 are rotatably inserted.
[0022]
The link rod 25 regulates the maximum swing range of the swing cam 17 within the swing range of the rocker arm 23.
[0023]
In addition, snap rings 29, 30, and 31 for restricting the axial movement of the link arm 24 and the link rod 25 are provided at one end of each pin 26, 27, and 28.
[0024]
The control mechanism 19 includes a control shaft 32 disposed in the longitudinal direction of the engine, a control cam 33 fixed to the outer periphery of the control shaft 32 and serving as a rocking fulcrum of the rocker arm 23, and a rotational position of the control shaft 32. It is comprised from the electric motor 34 which is an electric actuator to control.
[0025]
The control shaft 32 is provided in parallel with the drive shaft 13, and is rotatably supported between the bearing groove at the upper end of the main bracket 14a of the bearing 14 and the sub bracket 14b as described above. On the other hand, each of the control cams 33 has a cylindrical shape, and the position of the axis P1 is deviated from the axis P2 of the control shaft 32 by α as shown in FIG.
[0026]
The electric motor 34 is connected to the control shaft 32 through meshing of a first spur gear 35 provided at the front end portion of the drive shaft 34 a and a second spur gear 36 provided at the rear end portion of the control shaft 32. A rotational force is transmitted, and the system is driven by a control signal from a controller 37 that detects the operating state of the engine.
[0027]
On the other hand, the second variable mechanism 2 is provided on the tip end side of the drive shaft 13 as shown in FIG. 1, and a timing sprocket 40 to which rotational force is transmitted from the crankshaft of the engine by a timing chain (not shown), A sleeve 42 fixed to the front end of the drive shaft 13 by a bolt 41 from the axial direction, a cylindrical gear 43 interposed between the timing sprocket 40 and the sleeve 42, and the cylindrical gear 43 connected to the drive shaft 13. The hydraulic circuit 44 is a drive mechanism for driving in the longitudinal axis direction.
[0028]
In the timing sprocket 40, a sprocket portion 40b around which a chain is wound is fixed to a rear end portion of the cylindrical main body 40a by a bolt 45, and a front end opening of the cylindrical main body 40a is closed by a front cover 40c. . Further, helical inner teeth 46 are formed on the inner peripheral surface of the cylindrical main body 40a.
[0029]
The sleeve 42 is formed with a fitting groove for fitting the front end of the drive shaft 13 on the rear end side, and the timing sprocket 40 is attached to the front end holding groove at the front end via a front cover 40c. A coil spring 47 is mounted. Further, on the outer peripheral surface of the sleeve 42, a helical outer tooth 48 is formed.
[0030]
The cylindrical gear 43 is divided into two in the direction perpendicular to the axis, and the front and rear gear components are urged toward each other by pins and springs, and the inner teeth 46 and the outer teeth 48 are provided on the inner and outer peripheral surfaces. The inner and outer teeth of a helical tooth meshing with the first and second hydraulic chambers 49 and 50 formed at the front and rear are formed in sliding contact with each other by the hydraulic pressure relatively supplied to the first and second hydraulic chambers 49 and 50. To move to. In addition, the cylindrical gear 43 controls the intake valve 12 to the most retarded position at the maximum forward movement position hitting the front cover 40c, while controlling the intake valve 12 to the most advanced angle position at the maximum backward movement position. Yes. Further, when the hydraulic pressure of the first hydraulic chamber 49 is not supplied by the return spring 51 mounted in the second hydraulic chamber 50, the maximum hydraulic position is urged.
[0031]
The hydraulic circuit 44 includes a main gallery 53 connected to the downstream side of an oil pump 52 that communicates with an oil pan (not shown), and branches on the downstream side of the main gallery 53 to branch to the first and second hydraulic chambers 49, 50, first and second hydraulic passages 54, 55 connected to 50, a solenoid-type flow path switching valve 56 provided at the branch position, and a drain path 57 connected to the flow path switching valve 56. Has been.
[0032]
The flow path switching valve 56 is switched and driven by a control signal from the same controller 37 that drives and controls the electric motor 34 of the first variable mechanism 1.
[0033]
The controller 37 calculates a current engine operating state based on an engine speed signal from a crank angle sensor, an intake flow signal (load) from an air flow meter, and detection signals from various sensors such as an engine oil temperature sensor. Detection signals from the first position detection sensor 58 that detects the current rotational position of the control shaft 32 and the second position detection sensor 59 that detects the relative rotational position of the drive shaft 13 and the timing sprocket 40. Based on this, when a control signal is output to the electric motor 34 and the flow path switching valve 56 and one of the variable mechanisms 1 and 2 fails and locks, A control circuit is provided as a control means for continuously variably controlling the other variable mechanism within a predetermined range in accordance with the lock position.
[0034]
That is, the controller 37 determines the target lift characteristic of the intake valve 12, that is, the target rotational position of the control shaft 32, from the information signal such as the engine speed, the load, the oil temperature, the elapsed time after the engine start, etc. By rotating the electric motor 34 based on this, the control cam 33 is controlled to rotate to a predetermined rotational angle position via the control shaft 32. Further, the actual rotational position of the control shaft 32 is monitored by the first position detection sensor 58, and the control shaft 32 is rotated to the target phase by feedback control.
[0035]
Specifically, at the time of cranking and idling at the initial stage of engine start, the control shaft 32 is controlled to rotate in one direction by the control signal from the controller 37, and the control cam 33 is shown in FIG. As shown in the figure, the shaft center P1 of the control shaft 32 is held at the upper left rotation position, and the thick portion 33a rotates away from the drive shaft 13 upward. As a result, the entire rocker arm 23 moves upward with respect to the drive shaft 13. For this reason, each swing cam 17 is forcibly pulled up via the link rod 25 and rotated counterclockwise. Therefore, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the lift amount is transmitted to the swing cam 17 and the valve lifter 16 via the link rod 25. The lift amount L becomes smaller as shown in FIGS. For this reason, gas flow is strengthened, combustion is improved, fuel consumption can be improved, and engine rotation can be stabilized.
[0036]
In particular, at the time of cranking, the valve lift amount is set to zero or a minimum lift (Lmin) close to zero as shown in FIG. 7, so that the engine rotation rises well as will be described later.
[0037]
On the other hand, in the high rotation and high load range, the control shaft 32 is rotated in the other direction by the electric motor 34 in response to a control signal from the controller 37, and the control cam 33 is rotated to the position shown in FIGS. The part 33a is rotated downward. For this reason, the entire rocker arm 23 moves in the direction of the drive shaft 13 (downward), and the other end 23b presses the swing cam 17 downward via the link arm 25 so that the entire swing cam 17 is positioned. A fixed amount is rotated to the position shown (clockwise). Therefore, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the lift amount is transmitted to the swing cam 17 and the valve lifter 16 via the link rod 25. The lift amount L is the largest (Lmax) as shown in FIG. The lift amount change from the minimum lift (Lmin) to the maximum (Lmax) has characteristics (L1 to L6) as shown in FIG. Note that Lmin in FIG. 7 is a minimal lift close to zero, but it can also be made zero by further rotating the control shaft to the one side.
[0038]
On the other hand, the flow path switching valve 56 side determines the target advance amount of the intake valve 12 from the information signal from each sensor in the same manner as described above, and the flow path switching valve 56 determines the target hydraulic advance amount based on this command signal. The main gallery 53 is in communication for a predetermined time, and the second hydraulic passage 55 and the drain passage 57 are in communication for a predetermined time. As a result, the relative rotation position of the timing sprocket 40 and the drive shaft 13 is converted via the cylindrical gear 43 and controlled to the advance side. Also in this case, the actual relative rotation position of the drive shaft 13 is monitored in advance by the second position detection sensor 59, and the drive shaft is rotated to the target relative rotation position, that is, the target advance amount by feedback control. ing.
[0039]
Specifically, the hydraulic pressure is supplied only to the second hydraulic chamber 50 by the flow path switching valve 56 until the oil temperature reaches the predetermined temperature To from the start of the engine until the oil temperature reaches the predetermined temperature To, and the hydraulic pressure is supplied to the first hydraulic chamber 49. Not supplied. Therefore, as shown in FIG. 1, the cylindrical gear 43 is held at the maximum front position by the spring force of the return spring 51, and the drive shaft 13 is held at the maximum retarded rotational position. Thereafter, when the oil temperature exceeds a predetermined temperature To, the flow path switching valve 56 is driven by a control signal from the controller 37 in accordance with the operating conditions to cause the first hydraulic passage 54 and the main gallery 53 to communicate with each other. The time for communicating the hydraulic passage 55 and the drain passage 57 continuously changes. As a result, the cylindrical gear 43 moves from the foremost position to the rearmost position. Therefore, the opening / closing timing of the intake valve 12 is changed from the most retarded state of the solid line to the most advanced angle of the broken line as shown in FIG. It is continuously variable and controlled.
[0040]
It should be noted that the intake valve 12 does not interfere with the piston in the cylinder and the opposing exhaust valve when the intake valve 12 is controlled to the maximum lift by the first variable mechanism 1 and controlled to the maximum retarded position by the second variable mechanism 2. Is set to the correct configuration.
[0041]
Hereinafter, specific drive control of the first variable mechanism 1 and the second variable mechanism 2 by the controller 37 will be described based on the flowcharts shown in FIGS. 8 and 9.
[0042]
That is, first, in relation to the oil temperature after starting, as shown in FIG. 8, in section S1, it is determined by a timer whether or not a predetermined time to has been exceeded after engine starting. Based on the information from the oil temperature sensor, it is determined whether or not the current oil temperature exceeds the predetermined temperature To, and if it exceeds, both the first and second variable mechanisms 1 and 2 are driven in section S3. If the predetermined time to is not exceeded in S1 and section S2, or if the oil temperature is equal to or lower than the predetermined oil temperature To, in section S4, only the first variable mechanism 1 is driven and the second variable mechanism 2 is not driven.
[0043]
Therefore, at the time of cold start, only the valve lift control by the first variable mechanism 1 is performed, the valve timing control by the second variable mechanism 2 is not performed, and the intake valve 12 is held at the most retarded angle side. Therefore, the problem of variable operation failure due to the hydraulic drive source in this operating range does not occur, and engine performance such as startability improvement by valve lift control can be improved. Further, since the second variable mechanism 2 is also driven after the oil temperature rises, the engine performance can be greatly improved.
[0044]
Next, the control of the first variable mechanism 1 described above will be described with reference to FIG. 9. First, when the ignition switch is turned on in section S11, the first variable mechanism 1 is moved to the minimum lift (zero) in section S12 immediately after that. (Minimal lift close to). Subsequently, after the starter switch is turned on in section S13 and cranking is started, the lift is increased by the first variable mechanism 1 in section S14 as the engine speed (cranking speed) is increased by the solid line L3 shown in FIG. Control to increase up to.
[0045]
Subsequently, in section S15, it is determined whether or not the current oil temperature is higher than a predetermined temperature (T1) by an oil temperature sensor. If higher, in section S16, the first variable mechanism 1 according to the engine operating state is used. Variable lift control is performed. However, when the oil temperature is equal to or lower than T1, the lift control by the first variable mechanism 1 is fixed to the L3 in section S17.
[0046]
In this way, at the initial start time when cranking is started, since the lift is controlled to the minimum lift in section S12, the friction of the valve operating system is reduced, so that the engine rotation can be quickly started.
[0047]
Further, by the lift increase control in section S14, the gas exchange efficiency of the air-fuel mixture is improved, the engine torque rises quickly, and the startability can be greatly improved in combination with the rapid rise of the engine rotation.
[0048]
Further, when the oil temperature is equal to or lower than T1, in order to fix the lift to a lift having a low L3 in section S17, the speed of the mixed airflow from the intake valve 12 is increased to generate a strong gas flow in the cylinder. In addition, combustion at the start of cold engine can be improved, and fuel efficiency and exhaust emission performance can be improved.
[0049]
In addition, the first variable mechanism 1 in this embodiment exhibits the variable valve lift characteristics shown in FIG. 7 as described above, but considering the phase of the drive shaft 13 (valve lift phase) that becomes the maximum valve lift, from Lmax When the lift is lowered, the angle is advanced little by little, and when the lift is further lowered toward Lmin, a unique change characteristic is shown in which the angle is retarded from the middle. In the maximum valve lift, as shown in FIG. 6, the radius R1 of the drive eccentric circle of the drive cam 15, the axis X of the drive cam 15, and the pivot point Z of the protrusion 24b of the link arm 24 Is the moment when the line R2 connecting the two becomes a straight line. At this time, the direction of R1 is closer to the vertical direction line Q of the cylinder head 11 by the angle θ, that is, the advance side.
[0050]
Next, consider the case where the moving radius R1 of the drive cam 15 and the link arm 24 are in a straight line when the control shaft 32 rotates clockwise in the figure. That is, at this time, the angle θ gradually increases with the clockwise rotation of the control shaft 32, and becomes maximum when the moving radius R3 of the rocker arm 23 and the moving radius e of the control cam 33 are in a straight line (see FIG. 5). Then, when the control shaft 32 is further rotated clockwise as shown in FIG. 4, it decreases on the contrary (see FIG. 7). For this reason, the valve lift phase exhibits a unique change characteristic as described above.
[0051]
Next, when the first variable mechanism 1 or the second variable mechanism 2 breaks down in the operation range in which both the first and second variable mechanisms 1 and 2 are variably controlled, the controller 37 is controlled by the control circuit. 10 and control as shown in FIG.
[0052]
First, FIG. 1 In section S31, the information signal from each sensor is read in section S31. In section S32, the actual rotational position (corresponding to the lift amount) of the control shaft 32 is read from the first position detection sensor 58. Next, in section S33. The actual rotation position and the target rotation position are compared to determine whether or not the first variable mechanism 1 has failed. If it is determined that there is a failure, the control range (advance amount) in which the intake valve 12 and the piston and the intake valve 12 and the exhaust valve do not interfere with each other is calculated for the control position of the second variable mechanism 2 in section S34. Further, in section S35, the second variable mechanism 2 is continuously controlled within the predetermined control range.
[0053]
That is, when the first variable mechanism 1 fails during the maximum lift (Lmax) control, the second variable mechanism 2 is continuously controlled in the vicinity of the most retarded angle in order to avoid interference between the two engine valves. Further, when a failure occurs in the small lift (Lmin to L1) region, the second variable mechanism 2 is continuously controlled over a wide range from the most retarded angle to the most advanced angle. Thereby, performance deterioration can be suppressed. Furthermore, when a failure occurs in the middle lift L3 region, continuous control is performed in the range from the most retarded angle to the intermediate phase.
[0054]
Therefore, since the second variable mechanism 2 is continuously controlled within a range in which interference between the engine valves and the pistons can be avoided, it is possible to prevent the engine performance from being deteriorated.
[0055]
Next, FIG. 0 In section S21, the information signal from each sensor is read in section S21, and then the actual relative rotational position (corresponding to the advance amount) of the drive shaft 13 is read from the second position detection sensor 59 in section S22. In section S23, the actual relative rotation position and the target relative rotation position are compared to determine whether or not the second variable mechanism 2 has failed.
[0056]
Here, when it is determined that there is a failure, in section S24, a control range (lift amount) in which the intake valve 12, the piston and the exhaust valve do not interfere with each other is calculated for the control position of the first variable mechanism 1, and further in section S25 1 The variable mechanism 1 is continuously controlled within a predetermined control range.
[0057]
In other words, when the second variable mechanism 2 fails during the most advanced angle control, the first variable mechanism 1 is moved to the small lift region (L _min ~ L ₁ ) To control continuously. If there is a failure on the most retarded angle side, there is no problem of interference, so continuous control is performed in the entire range from the minimum to the maximum lift. Further, when a failure occurs in the intermediate phase, continuous control is performed in the range from the minimum lift to the middle lift L3.
[0058]
As described above, even when the second variable mechanism 2 fails, the first variable mechanism 1 can be continuously controlled within a range in which interference between the intake valve 12 and the piston can be avoided, so that deterioration in engine performance is suppressed as much as possible. it can. Further, the same effect can be obtained by continuously controlling in multiple stages. In this case, the control is simplified.
[0059]
In this embodiment, since the swing cam 17 is linked to the rocker arm 23 by the link rod 25, the maximum swing range of the swing cam 17 is within the swing range of the rocker arm 23 by the link rod 25. Can be regulated. Therefore, even in a high rotation range, so-called dance phenomena such as excessive swinging and jumping of the swing cam 17 can be reliably prevented. For this reason, collision due to separation / contact between the rocking cam 17 and the rocker arm 23 is avoided, the occurrence of hitting sound is prevented, and the control accuracy of the valve lift is prevented from being lowered. Stabilization can be achieved.
[0060]
In the present embodiment, as described above, the valve lift phase changes peculiarly with the lift change, but the first variable mechanism 1 and the second variable mechanism 2 that changes the rotational phase of the drive shaft 13 are combined. This makes it possible to correct this unique change. That is, for example, if the engine operating state is controlled to a large valve lift by the first variable mechanism 1 in a high rotation or high load range, and the valve lift phase is controlled to approach the top dead center by the second variable mechanism 2, the valve By increasing the overlap and synchronizing the negative pressure wave of exhaust pulsation with a large valve overlap period, the residual gas in the cylinder can be scavenged, so the intake efficiency of fresh air is improved and the output is greatly improved Is possible.
[0061]
The present invention is not limited to the above-described embodiment, and can be applied to, for example, the exhaust side. By controlling the first variable mechanism 1 to zero or minimal lift at the initial stage of the start, As in the case, the valve friction can be reduced, a smooth rise characteristic of the engine speed can be obtained, and the gas exchange efficiency can be improved by variably controlling the lift amount to increase as the engine speed increases. Thus, the same effect as the intake side can be obtained, for example, good startability can be obtained.
[0062]
Also, when applied to the exhaust side, as with the intake side, if one of the variable mechanisms breaks down, the other variable mechanism can be controlled as much as possible, thus reducing engine performance while avoiding mechanical inconveniences. Of course, this can be prevented.
[0063]
Further, the present invention may be applied to any drive source for each variable mechanism regardless of whether it is hydraulic or electric, and both variable mechanisms are driven by the same electric or hydraulic pressure. is there.
[0064]
【The invention's effect】
According to the first to third aspects of the invention, the first variable mechanism and the second variable mechanism can significantly improve the engine performance in accordance with the engine operating state. If either one of the second variable mechanisms fails, the other variable mechanism is connected to the interference between the engine valve and the piston and the intake and exhaust valves according to the position at the time of the failure of one variable mechanism by the control means. Since the control can be performed continuously or stepwise as much as possible within a predetermined range in which the interference can be avoided, it is possible to prevent the engine performance from deteriorating while avoiding the mechanical trouble.
[0065]
According to the fourth aspect of the present invention, the valve lift amount can be continuously variably controlled by rotating the control cam, and the variation range of the valve lift amount can be increased. If the engine does not occur, the engine performance can be sufficiently exerted even if a failure occurs.
[0066]
Moreover, due to the use of the control cam, the valve lift phase shows a singular change along with the lift change, but the singular change is corrected by combining a second variable mechanism that changes the phase of the drive shaft. As a result, the engine performance can be sufficiently exhibited when each variable mechanism is not broken down.
[0067]
According to the fifth aspect of the present invention, since the maximum swinging range of the swing cam can be regulated within the swing range of the rocker arm by the linkage member, excessive swinging of the swing cam is possible even in the high rotation range. Dance phenomena such as movement and jumping can be reliably prevented. For this reason, collision due to separation / contact between the swing cam and the rocker arm can be avoided to prevent the generation of a hitting sound, and the control accuracy of the valve lift can be prevented from being lowered, and the engine performance can be stabilized particularly in a high rotation range. .
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a plan view of the first variable mechanism.
FIG. 4 is an explanatory diagram of the operation of the minimum lift control of the first variable mechanism.
FIG. 5 is an operation explanatory view showing a process of controlling the first variable mechanism from the maximum to the minimum lift.
FIG. 6 is an explanatory diagram of the operation of the maximum lift control of the first variable mechanism.
FIG. 7 is a characteristic diagram of valve lift and valve timing of the present embodiment.
FIG. 8 is a flowchart of control by the controller of the present embodiment.
FIG. 9 is a flowchart of control by the controller of the present embodiment.
FIG. 10 is a flowchart of control by the controller of the present embodiment.
FIG. 11 is a flowchart of control by the controller of the present embodiment.
[Explanation of symbols]
1 ... 1st variable mechanism
2 ... Second variable mechanism
12 ... Intake valve
13 ... Drive shaft
17 ... Oscillating cam
19 ... Control mechanism
23 ... Rocker arm
24 ... Link arm
25 ... Link rod (linkage member)
34 ... Electric motor
37 ... Controller
58... First position detection sensor
59 ... Second position detection sensor

Claims (5)

A first variable mechanism that continuously and variably controls at least a lift characteristic of the engine valve according to an engine operating state;
A second variable mechanism that continuously variably controls at least the opening / closing timing characteristics of the engine valve according to the engine operating state;
Position detecting means for detecting a current operating position of the first variable mechanism or the second variable mechanism;
Control target value determining means for determining a control target value of the first variable mechanism or the second variable mechanism based on a current engine operating state;
When one of the first variable mechanism and the second variable mechanism fails, the control range of the other variable mechanism is set to a predetermined range based on the position of the one variable mechanism detected by the position detecting means. And the control target value determined by the control target value determining means based on the operating position of the other variable mechanism detected by the detecting means within the set predetermined control range, Control means for feedback-controlling the other variable mechanism continuously or stepwise;
A variable valve operating apparatus for an internal combustion engine, comprising: A first variable mechanism that continuously and variably controls at least a lift characteristic of the engine valve according to an engine operating state;
A second variable mechanism that continuously variably controls at least the opening / closing timing characteristics of the engine valve according to the engine operating state;
First position detecting means for detecting a current operating position of the first variable mechanism;
Second position detecting means for detecting a current operating position of the second variable mechanism;
First control target value determining means for determining a control target value of the first variable mechanism based on a current engine operating state;
When the second variable mechanism fails, the control range of the first variable mechanism is set to a predetermined control range based on the position of the second variable mechanism detected by the second position detecting unit when the second variable mechanism fails. Based on the operation position detected by the first position detection means and the control target value determined by the first control target value determination means within the set predetermined control range, the first variable mechanism is Control means for feedback control continuously or stepwise;
A variable valve operating apparatus for an internal combustion engine, comprising: A first variable mechanism that continuously and variably controls at least a lift characteristic of the engine valve according to an engine operating state;
A second variable mechanism that continuously variably controls at least the opening / closing timing characteristics of the engine valve according to the engine operating state;
First position detecting means for detecting a current operating position of the first variable mechanism;
Second position detecting means for detecting a current operating position of the second variable mechanism;
Second control target value determining means for determining a control target value of the second variable mechanism based on a current engine operating state;
When the first variable mechanism fails, the control range of the second variable mechanism is set to a predetermined control range based on the position of the first variable mechanism detected by the first position detecting unit when the first variable mechanism fails. At the same time, within the set predetermined control range, the second variable mechanism is continuously operated based on the operation position detected by the second position detection means and the control target value determined by the second control target value determination means. Control means for feedback control in a stepwise or stepwise manner,
A variable valve operating apparatus for an internal combustion engine, comprising:   The first variable mechanism includes a drive shaft having a drive cam on the outer periphery, a swing cam that is swingably supported by a support shaft and swings to open and close the engine valve, and one end portion of the drive cam And a rocker arm whose other end is rotatably linked to the swing cam and whose swing center is variably controlled by the control cam. The variable valve operating apparatus for an internal combustion engine according to any one of the above.   The first variable mechanism includes a drive shaft having a drive cam on the outer periphery, a link arm having one end rotatably linked to the outer periphery of the drive cam, and one end rotatably linked to the other end of the link arm. In addition, a rocker arm whose swing center is variably controlled by a control cam, a swing cam that opens and closes an engine valve, and the swing cam and the other end of the rocker arm are mechanically linked in a freely rotatable manner. And a actuator for controlling the rotation of the control cam via a control shaft in accordance with an engine operating state. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 3.

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