JP4922514B2 - 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 device used for an intake valve of an internal combustion engine, and more particularly to a variable valve operating device capable of continuously expanding and reducing the lift of the intake valve.
[0002]
[Prior art]
For example, Japanese Patent Application Laid-Open No. 2000-282901 discloses a variable valve operating device that can simultaneously and continuously expand and contract the lift / operating angle of an intake valve. In this apparatus, lift characteristics change depending on the rotational position of a control shaft provided with an eccentric cam portion that swingably supports a rocker arm, and the control shaft is driven by an actuator using a DC servo motor. It has become. The actual rotational position of the control shaft is detected by an angle sensor made up of a potentiometer or the like, and the actuator is closed-loop controlled so as to be a target rotational position corresponding to the operating conditions.
[0003]
[Problems to be solved by the invention]
Since the angular position signal output from the angle sensor is generally an analog signal, the control circuit for controlling the actuator is treated as a digital signal after being discretized with an appropriate resolution. The level of resolution at the time of discretization naturally affects the control accuracy. However, if processing is always performed with a high resolution, the storage capacity required for the control circuit increases and the computation time increases. A highly functional arithmetic circuit is required. On the other hand, if the control is performed with a relatively low resolution, the calculation load of the control circuit is reduced, but the control accuracy is lowered and an error occurs in the valve lift characteristic. In particular, in an operation region in which the intake valve lift is limited to a minimum lift and the intake air amount is limited, combustion variation may occur due to variations in valve lift characteristics, and operability may deteriorate.
[0004]
[Means for Solving the Problems]
  The invention according to claim 1 is a variable valve mechanism capable of continuously and variably controlling the lift of the intake valve;Target value setting means for setting a target lift of the variable valve mechanism based on engine load and rotational speed; andA sensor that outputs a signal corresponding to the actual control state of the variable valve mechanism, and captures the signal of the sensor with a predetermined resolution.Target liftAnd a control means for calculating a control command value for the variable valve mechanism based on the variable valve mechanism of the internal combustion engine,
  Based on the target lift and the engine speed, when the target lift is small and the engine speed is low,The above resolutionRelatively highHigh resolutionToIt is characterized by that.
[0005]
  That is, the variable valve mechanism is calculated by the control means.Target liftDriven by some actuator. Then, the actual control state is detected by the sensor, and closed loop control is performed by the control means. As the sensor, a sensor that detects the final lift amount of the intake valve or a sensor that detects the position of any intermediate member that is moved by an actuator can be used, and its output signal is discrete with a predetermined resolution. Is taken into the control means.
[0006]
  And under conditions controlled by a large lift, the sensor output is processed with a relatively low resolution. In contrast, under conditions controlled by a small lift,As a weighting condition that the engine speed is in a predetermined low speed range,Sensor output is processed with relatively high resolution. As a result, the valve lift characteristic when controlled to a small lift is closed-loop controlled with high accuracy.
[0007]
When controlled to a small lift, the same control error has a greater effect on the intake air amount in the cylinder than at a high lift. In particular, variations in intake valve opening timing and intake valve closing timing during small lifts include not only intake air amount but also residual gas amount, effective compression ratio, intake air flow velocity (especially when the opening time is after top dead center), etc. Affects and greatly affects combustion. In the present invention, the variation in the intake valve opening timing and the intake valve closing timing during the small lift is reduced.
[0010]
  Further claims2The invention according to the present invention includes an eccentric cam that is rotationally driven by a drive shaft, a link arm that is fitted to the outer periphery of the eccentric cam so as to be relatively rotatable, and provided at least with an eccentric cam portion provided in parallel to the drive shaft. A control shaft that is rotatable within a predetermined angle range, a rocker arm that is rotatably mounted on an eccentric cam portion of the control shaft and is rocked by the link arm, and is rotatably supported by the drive shaft; A rocking cam connected to the rocker arm via a link and pushing the intake valve by rocking with the rocker arm, and the lift of the intake valve is controlled by the rotational position of the eccentric cam portion of the control shaft. It is configured to increase or decrease with the operating angle, and the rate of increase of the lift with respect to the unit swing angle of the swing cam is smaller in the large lift region than in the small and medium lift regions. A variable valve mechanism in which the cam profile of the swing cam is set,
  Target value setting means for setting a target lift of the variable valve mechanism based on the engine load and the rotational speed;
  An actuator for changing the rotational position of the control shaft;
  A sensor that outputs a signal corresponding to the actual rotational position of the control shaft;
  The sensor signal is captured with a predetermined resolution, and the captured sensor output andAbove target liftControl means for calculating a control command value for the actuator based on
  In a variable valve operating apparatus for an internal combustion engine comprising:
  Based on the target lift and the engine speed, when the target lift is small and the engine speed is low,The above resolutionRelatively highHigh resolutionToIt is characterized by that.
[0011]
In the above variable valve mechanism, when the drive shaft rotates, the link arm moves up and down by the eccentric cam, and the rocker arm swings. The movement of the rocker arm is transmitted to the swing cam via the link, and the intake valve opens and closes as the swing cam swings. And the rocking | swiveling center position of a rocker arm changes with the position of the eccentric cam part of the said control shaft, and the initial position of a rocking cam changes. Therefore, the characteristics of the lift that actually occurs with respect to the swing of the swing cam change. The rotational position of the control shaft is moved by an actuator, and the actual rotational position is detected by a sensor.
[0012]
Here, as the cam profile of the swing cam, in order to improve the valve motion limit in the high speed region, the lift increase rate with respect to the unit swing angle of the swing cam is smaller in the large lift region than in the small and medium lift regions. It is desirable to set so that By setting it as such a profile, the negative acceleration absolute value of the intake valve near the maximum lift is suppressed. On the other hand, under such characteristics, the amount of lift change when the swing cam swings by a constant swing angle due to the change in the rotational position of the control shaft is also relatively large in the small and medium lift regions, and large. It is relatively small in the lift area. Therefore, even if the initial swing position of the swing cam varies by a certain angle due to the control error of the control shaft, the effect on the final lift amount is relatively small when the large lift is controlled, and the small lift It is relatively large in the controlled state.
[0013]
Therefore, by processing the sensor output with high resolution when controlled by a small lift, it is possible to avoid deterioration in control accuracy when controlled by a small lift.
[0014]
Further, as will be described in detail later, in this type of variable valve mechanism, in general, when controlling to the largest lift, the position of the eccentric cam portion of the control shaft is the rotational position closest to the drive shaft. In many cases, the eccentric cam portion is laid out so as to face in a lateral direction with respect to a line connecting the control shaft and the drive shaft. Therefore, the amount of rotation of the swing cam (angle change amount) when the control shaft rotates by a unit angle is generally larger during small lift control than during large lift control. In other words, the posture of the link when controlled to a large lift is less sensitive to the rotational position error of the control shaft than the posture of the link when controlled to a small lift. Therefore, it is more desirable to vary the resolution as described above.
[0015]
【The invention's effect】
According to the present invention, the resolution at the time of capturing the output of the sensor that detects the actual control state in order to perform the closed-loop control of the variable valve mechanism is made suitable for the required control accuracy that varies depending on the lift control conditions. Therefore, highly accurate control can be realized with a relatively small control capacity. In particular, when the amount of intake air into the cylinder is controlled by variable control of the intake valve lift, it is possible to accurately secure a minimal lift that has a large effect on the combustion state, and to reduce combustion deterioration due to variations in lift characteristics. It can be avoided.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments in which the present invention is applied to an intake valve of a spark ignition gasoline engine for automobiles will be described below.
[0017]
FIG. 1 is a configuration explanatory view showing the configuration of an intake valve side variable valve operating device of an internal combustion engine. This variable valve operating device serves as a variable valve operating mechanism for changing the lift / operating angle of an intake valve. The angle variable mechanism 1 and a phase variable mechanism 21 that advances or retards the phase of the center angle of the lift (phase with respect to a crankshaft (not shown)) are provided.
[0018]
First, the lift / operating angle variable mechanism 1 will be described. The lift / operating angle variable mechanism 1 has been previously proposed by the applicant of the present application. However, since it has been publicly known, for example, in Japanese Patent Application Laid-Open No. 11-107725, only the outline thereof will be described.
[0019]
The variable lift / operating angle mechanism 1 includes an intake valve 11 slidably provided on a cylinder head (not shown) and a drive shaft 2 rotatably supported by a cam bracket (not shown) on the cylinder head. And an eccentric cam 3 fixed to the drive shaft 2 by press-fitting or the like, and a control shaft 12 that is rotatably supported by the same cam bracket at a position above the drive shaft 2 and arranged in parallel with the drive shaft 2. And a rocker arm 6 that is swingably supported by the eccentric cam portion 18 of the control shaft 12, and a swing cam 9 that contacts the tappet 10 disposed at the upper end of each intake valve 11. The eccentric cam 3 and the rocker arm 6 are linked by a link arm 4, and the rocker arm 6 and the swing cam 9 are linked by a link member 8.
[0020]
As will be described later, the drive shaft 2 is driven by a crankshaft of an engine via a timing chain or a timing belt.
[0021]
The eccentric cam 3 has a circular outer peripheral surface, and the center of the outer peripheral surface is offset from the shaft center of the drive shaft 2 by a predetermined amount, and the annular portion of the link arm 4 is rotatable on the outer peripheral surface. It is mated.
[0022]
The rocker arm 6 has a substantially central portion supported by the eccentric cam portion 18 so as to be swingable, and an arm portion of the link arm 4 is linked to one end portion thereof via a connecting pin 5. The upper end portion of the link member 8 is linked to the end portion via the connecting pin 7. The eccentric cam portion 18 is eccentric from the axis of the control shaft 12, and accordingly, the rocking center of the rocker arm 6 changes according to the angular position of the control shaft 12.
[0023]
The rocking cam 9 is fitted to the outer periphery of the drive shaft 2 and is rotatably supported, and the lower end portion of the link member 8 is linked to the end portion extending sideways via a connecting pin 17. ing. On the lower surface of the swing cam 9, a base circle surface concentric with the drive shaft 2 and a cam surface extending in a predetermined curve from the base circle surface are continuously formed. These base circle surface and cam surface are in contact with the upper surface of the tappet 10 according to the swing position of the swing cam 9.
[0024]
That is, the base circle surface is a section where the lift amount becomes 0 as a base circle section, and when the swing cam 9 swings and the cam surface comes into contact with the tappet 10, it gradually lifts. A slight ramp section is provided between the base circle section and the lift section.
[0025]
As shown in FIG. 1, the control shaft 12 is configured to rotate within a predetermined angle range by a lift / operation angle control actuator 13 provided at one end. The lift / operating angle control actuator 13 includes, for example, a servo motor that drives the control shaft 12 via the worm gear 15, and is controlled by a control signal from the engine control unit 19. Here, the rotation angle of the control shaft 12 is detected by a control shaft sensor 14 formed of an analog sensor, and the actuator 13 is closed-loop controlled based on the detected actual control state.
[0026]
The operation of the variable lift / operating angle mechanism 1 will be described. When the drive shaft 2 rotates, the link arm 4 moves up and down by the cam action of the eccentric cam 3, and the rocker arm 6 swings accordingly. The swing of the rocker arm 6 is transmitted to the swing cam 9 via the link member 8, and the swing cam 9 swings. The tappet 10 is pressed by the cam action of the swing cam 9, and the intake valve 11 is lifted.
[0027]
Here, when the angle of the control shaft 12 changes via the lift / operation angle control actuator 13, the initial position of the rocker arm 6 changes, and consequently, the initial swing position of the swing cam 9 changes.
[0028]
For example, if the eccentric cam portion 18 is positioned upward in the figure, the rocker arm 6 is positioned upward as a whole, and the end of the swing cam 9 on the side of the connecting pin 17 is relatively lifted upward. Become. That is, the initial position of the swing cam 9 is inclined in a direction in which the cam surface is separated from the tappet 10. Therefore, when the swing cam 9 swings as the drive shaft 2 rotates, the base circle surface is kept in contact with the tappet 10 for a long time, and the period during which the cam surface is in contact with the tappet 10 is short. Therefore, the lift amount is reduced as a whole, and the angle range from the opening timing to the closing timing, that is, the operating angle is also reduced.
[0029]
Conversely, assuming that the eccentric cam portion 18 is positioned downward in the figure, the rocker arm 6 is positioned downward as a whole, and the end of the swing cam 9 on the side of the connecting pin 17 is relatively pushed downward. It becomes a state. That is, the initial position of the swing cam 9 is inclined in a direction in which the cam surface approaches the tappet 10. Therefore, when the swing cam 9 swings as the drive shaft 2 rotates, the portion that contacts the tappet 10 immediately shifts from the base circle surface to the cam surface. Therefore, the lift amount is increased as a whole, and the operating angle is increased.
[0030]
Since the initial position of the eccentric cam portion 18 can be continuously changed, the valve lift characteristic is continuously changed accordingly. That is, the lift and the operating angle can be continuously expanded and contracted simultaneously. Depending on the layout of each part, for example, the opening timing and closing timing of the intake valve 11 change substantially symmetrically as the lift and operating angle change.
[0031]
Next, as shown in FIG. 1, the phase variable mechanism 21 relatively connects the sprocket 22 provided at the front end of the drive shaft 2, and the sprocket 22 and the drive shaft 2 within a predetermined angle range. And a phase control actuator 23 to be rotated. The sprocket 22 is interlocked with the crankshaft via a timing chain or a timing belt (not shown). The phase control actuator 23 is composed of, for example, a hydraulic or electromagnetic rotary actuator, and is controlled by a control signal from the engine control unit 19. The action of the phase control actuator 23 causes the sprocket 22 and the drive shaft 2 to rotate relative to each other, thereby delaying the lift center angle in the valve lift. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can also be obtained continuously. The actual control state of the phase variable mechanism 21 is detected by the drive shaft sensor 16 that responds to the rotational position of the drive shaft 2, and based on this, the actuator 23 is closed-loop controlled.
[0032]
In the internal combustion engine of the present embodiment provided with such a variable valve device on the intake valve side, the intake amount is controlled by variable control of the intake valve 11 without depending on the throttle valve. In a practical engine, it is preferable that a slight negative pressure exists in the intake system for recirculation of blow-by gas and the like, although not shown, instead of a throttle valve on the upstream side of the intake passage, It is desirable to provide an appropriate throttle mechanism for generating negative pressure.
[0033]
Next, specific control of the valve lift characteristics will be described based on FIGS. First, FIG. 2 shows a valve lift control region in which the intake amount is controlled mainly focusing on the lift amount in the operation region, and a valve timing in which the intake amount control is mainly focused on the valve timing. And the control area. The upstream valve lift control region corresponds to an extremely low load region including idle.
[0034]
FIG. 3 shows the valve lift characteristics of the intake valve under typical operating conditions. As shown in the figure, the lift amount is a minimum lift in an extremely low load region such as an idle. In particular, the lift amount is so small that the phase of the lift center angle does not affect the intake air amount. The phase of the lift center angle by the phase variable mechanism 21 is the most retarded position, so that the closing timing is the position immediately before the bottom dead center.
[0035]
By setting the minimum lift in this way, the intake flow becomes choked in the gap between the intake valves 11, and the necessary minute flow rate can be stably obtained in the extremely low load region. Since the closing time is near the bottom dead center, the effective compression ratio is sufficiently high, and it is possible to ensure relatively good combustion in combination with the improvement of gas flow by the minimal lift.
[0036]
On the other hand, in the low load region where the load is higher than the extremely low load region such as idle (including the idle state where the auxiliary load is applied), the lift / operating angle is large and the lift center angle is the advanced position. It becomes. At this time, as described above, the intake air amount control is performed in consideration of the valve timing, and the intake air amount is controlled to a relatively small amount by advancing the intake valve closing timing. As a result, the lift / operating angle becomes somewhat large, and the pumping loss due to the intake valve 11 is reduced.
[0037]
Note that in the case of a minimal lift in an extremely low load range such as idle, the intake air amount hardly changes even if the phase is changed, as described above, so when shifting from the very low load range to the low load range, Prior to the change, it is necessary to enlarge the lift and operating angle. The same applies when a load of auxiliary equipment such as an air conditioning compressor is applied.
[0038]
On the other hand, in the middle load region where the load is further increased and the combustion is stabilized, as shown in FIG. 3, the phase of the lift center angle is advanced while further increasing the lift / operation angle. The phase of the lift center angle is the most advanced state at a certain point in the middle load region. Thereby, internal EGR is utilized and the pumping loss can be further reduced.
[0039]
In addition, at the maximum load, the phase variable mechanism 21 is controlled so that the lift / operation angle is further expanded and the optimum valve timing is obtained. As shown in the figure, the optimum valve lift characteristic varies depending on the engine speed.
[0040]
As described above, in an extremely low load range such as an idle, a minute flow rate is controlled mainly by a lift amount as a valve lift control range, but a boundary with a low load range that is a valve timing control range, that is, control switching. The point is preferably corrected according to the actual stable combustion state. Alternatively, for simplification of control, it is also possible to detect the engine temperature and correct it accordingly. By correcting in this way, the valve timing control region can be expanded within a range that does not cause deterioration of combustion, which is advantageous in reducing pumping loss.
[0041]
Next, FIG. 4 is a flowchart showing a control flow of the variable valve operating apparatus. The routine shown in this flowchart is repeatedly executed in the control unit 19 at regular intervals, for example.
[0042]
First, in step 1, the required torque / output is calculated from the accelerator pedal opening, the vehicle speed, etc., and in steps 2 and 3, the engine speed, load and engine temperature are detected. Set lift / working angle and phase. In step 5, the lift / operating angle variable mechanism 1 is closed-loop controlled so as to follow the target value at that time, and in step 6, the phase-variable mechanism 21 is also closed-loop controlled so as to follow the target value at that time. To do.
[0043]
FIG. 5 is a flowchart showing details of step 5 above. In step 11, it is determined whether or not the target lift previously obtained in step 4 is larger than the set value. If the target lift is a small / medium lift that is less than or equal to the set value, the process proceeds to step 12 and a relatively high resolution is selected as the resolution for discretizing the analog signal. Capture the output signal. In step 13, a deviation is calculated and a necessary control amount is calculated from the acquired control axis position signal and target value. In step 14, a drive signal is output to the lift / operation angle control actuator 13. .
[0044]
If the target lift is a large lift larger than the set value in step 11, the process proceeds to step 15 where a relatively low low resolution is selected and the output signal of the control axis sensor 14 is captured with this low resolution. In step 16, a deviation is calculated and a necessary control amount is calculated from the acquired control axis position signal and target value. In step 14, a drive signal is output to the lift / operation angle control actuator 13. .
[0045]
In this way, high resolution at the time of small lift control that requires high-precision control of the lift and the operating angle can realize high-precision closed-loop control based on detection of the rotational position of the control shaft 12, and lift characteristics. It is possible to avoid the deterioration of combustion caused by the variation in the number. Further, during large lift control in which some control error is allowed, the resolution becomes low, so that the control load is reduced and a control circuit having a relatively small control capacity can be used.
[0046]
In the flowchart of FIG. 5, the resolution is selected based on the target lift itself. However, as described above, since the engine is controlled to a small lift and operating angle in the engine low speed range, the engine speed is set to a predetermined value. Compared with the rotation speed, the resolution may be higher only in a predetermined low speed range. In general, combustion stability is a problem at low engine speeds. Therefore, in addition to the target lift being a small lift, the engine speed is determined as a weighting condition. You may make it. Similarly, since the combustion stability deteriorates with a low load, the high resolution may be achieved only in a small lift (or engine low speed region) and in a low load region.
[0047]
FIG. 6 shows details of the cam profile of the swing cam 9 in the above-described variable lift / operating angle mechanism 1. (A) in the figure shows the relationship between the swing angle and the valve lift, and (B) in the figure shows the relationship between the swing angle and the valve lift speed. As shown in these figures, A deceleration region is provided in a region close to the maximum lift of the valve lift, and the lift increase rate with respect to the unit swing angle is set to be smaller in the large lift region than in the small and medium lift regions. This contributes to suppressing the negative acceleration absolute value of the intake valve 11 near the maximum lift and improving the valve motion limit in the high speed range. With such a profile, even if there is a certain variation in the swing angle, the variation in lift amount in the large lift region is relatively small, and the variation in lift amount in the small lift region is relatively large. Become.
[0048]
FIG. 8 shows the cam characteristics of the eccentric cam portion 18 in the lift / operating angle variable mechanism 1 described above. As described above, in the lift / operating angle variable mechanism 1, when the eccentric cam portion 18 rotates together with the control shaft 12, the rocker arm 6 moves up and down to change the initial position of the swing cam 9. However, as described in FIG. 8, the initial position of the swing cam 9 is the center O2 of the eccentric cam portion 18 that also serves as the swing center of the rocker arm 6 and the swing center of the swing cam 9 (the center of the drive shaft 2). ) Generally corresponds to the distance to O3. That is, when the distance between O2 and O3 is shortened, the swing cam 9 is pushed down in advance and becomes a large lift, and when the distance between O2 and O3 is increased, the swing cam 9 is pulled up in advance and becomes a small lift. Since the center O2 of the eccentric cam portion 18 is rotated around the center O1 of the control shaft 12, the distance O2-O3 when the control shaft 12 is rotated by a unit angle (for example, 1 degree). The amount of change varies depending on the posture of the eccentric cam portion 18 at that time (the position of the point O2 with respect to the point O1). FIG. 8 shows this as the distance between O2 and O3 on the horizontal axis and the amount of change in the distance between O2 and O3 per degree of the control axis 12 on the vertical axis. In general, in order to reduce the size of the lift / operating angle variable mechanism 1, the center O2 of the eccentric cam portion 18 is positioned close to the drive shaft 2 center O3 when the maximum lift is controlled. Composed. In other words, the point O2 is located on or near a straight line connecting the point O1 and the point O3. Accordingly, at this point O2, as shown in FIG. 8, the change in the distance between O2 and O3 when the control shaft 12 rotates by a unit angle (this corresponds to the amount of change in lift as described above) is as follows. small. On the other hand, in order to maximize the distance between O2 and O3 for the smallest lift, the point O2 is positioned on the opposite side of the point O3 with the point O1 interposed therebetween. Control within a range of degrees is limited in terms of control responsiveness and overall height of the apparatus. Therefore, as shown in FIG. 8, the range is narrower than 180 degrees (for example, up to a range indicated by L). Limiting the control range of the control shaft 12 is a general layout. In this case, at the time of the small lift control, the point O2 is positioned on the side of the straight line connecting the point O1 and the point O3. Therefore, the distance between O2 and O3 when the control shaft 12 is rotated by a unit angle. The amount of change, that is, the amount of change in lift is large.
[0049]
FIG. 7 summarizes the relationship between the rotational position of the control shaft 12 and the valve lift in the lift / operating angle variable mechanism 1 including the cam profile of the swing cam 9 and the layout of the eccentric cam portion 18 as described above. It is shown. As shown in this figure, the change in the lift amount with respect to the rotation of the control shaft 12 is large during a small lift, and the change in the lift amount with respect to the rotation of the control shaft 12 is small during a large lift. Therefore, by varying the resolution as described above, it is possible to achieve sufficiently accurate variable control of lift and operating angle without requiring an excessive control capacity.
[0050]
In the above embodiment, the control shaft sensor 14 that detects the rotational position of the control shaft 12 is used as the sensor that detects the actual control state. Instead, for example, the lift position of the intake valve 11 is used. The actual control state of the lift / operating angle variable mechanism 1 is detected from a sensor that sequentially detects the position, a sensor that detects the maximum lift amount in the cycle, or a sensor that detects the swing position of the swing cam 9. You may do it. However, since the lift position at each crank angle of the intake valve 11 is also influenced by the phase variable mechanism 21, it is necessary to consider this.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a variable valve operating apparatus according to the present invention.
FIG. 2 is a characteristic diagram showing a valve lift control region and a valve timing control region.
FIG. 3 is a characteristic diagram showing valve lift characteristics under typical operating conditions.
FIG. 4 is a main flowchart showing a flow of control of the variable valve operating apparatus.
FIG. 5 is a flowchart showing details of control of a lift / operating angle variable mechanism.
FIG. 6 is a characteristic diagram showing a cam profile of a swing cam.
FIG. 7 is a characteristic diagram showing a relationship between a rotation angle of a control shaft and a valve lift.
FIG. 8 is a characteristic diagram showing the relationship between the distance between O2 and O3 and the change in the distance per degree of control axis.
[Explanation of symbols]
1 ... Lift / operating angle variable mechanism
2 ... Drive shaft
3 ... Eccentric cam
6 ... Rocker arm
8 ... Link member
9 ... Oscillating cam
11 ... Intake valve
12 ... Control axis
14 ... Control axis sensor
16 ... Drive shaft sensor
19 ... Engine control unit
21 ... Phase variable mechanism

Claims (2)

A variable valve mechanism capable of continuously and variably controlling the lift of the intake valve, target value setting means for setting a target lift of the variable valve mechanism based on the load and rotation speed of the engine, and the variable valve mechanism A sensor that outputs a signal corresponding to the actual control state of the sensor, and the sensor signal is captured with a predetermined resolution, and a control command value for the variable valve mechanism is calculated based on the captured sensor output and the target lift. And a variable valve operating apparatus for an internal combustion engine comprising:
Based on the above target lift and the engine rotational speed, when the target lift is small and the engine rotational speed is slow, the engine, characterized in that the resolution is relatively high high-resolution variable Variable valve device. An eccentric cam that is rotationally driven by a drive shaft, a link arm that is fitted to the outer periphery of the eccentric cam so as to be relatively rotatable, and provided in parallel with the drive shaft and within an at least predetermined angle range provided with an eccentric cam portion. A control shaft that is rotatable, a rocker arm that is rotatably mounted on an eccentric cam portion of the control shaft, and is swingably supported by the link arm, and is rotatably supported by the drive shaft, and has a link to the rocker arm. And a swing cam that presses the intake valve by swinging with the rocker arm, and the lift of the intake valve changes with the operating angle according to the rotational position of the eccentric cam portion of the control shaft. The swing cam is configured so that the lift increase rate with respect to the unit swing angle of the swing cam is smaller in the large lift region than in the small and medium lift regions. A variable valve mechanism in which the cam profile is set,
Target value setting means for setting a target lift of the variable valve mechanism based on the engine load and the rotational speed;
An actuator for changing the rotational position of the control shaft;
A sensor that outputs a signal corresponding to the actual rotational position of the control shaft;
Control means for taking in the signal of the sensor with a predetermined resolution, and calculating a control command value for the actuator based on the taken-in sensor output and the target lift ;
In a variable valve operating apparatus for an internal combustion engine comprising:
Based on the above target lift and the engine rotational speed, when the target lift is small and the engine rotational speed is slow, the engine, characterized in that the resolution is relatively high high-resolution variable Variable valve device.

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