JP2008215239A - Variable valve mechanism for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To successfully vary valve lift amount by using oscillating actions while suitably suppressing change in the valve lift amount due to uneven wear of a cam, in a variable valve mechanism for an internal combustion engine. <P>SOLUTION: The cam 58 having two oscillation cam faces comprising a zero lift face 58a and a pressing face 58b is provided in each cylinder. By oscillating the cam 58 by a motor 54A, the lift amount of a valve can be changed. At start of the oscillating action, one oscillation cam face to be used during the oscillating action is selected from the two oscillation cam faces. At this time, the one oscillation cam face as a control target is selected so that execution times (mode 1 action time, mode 2 action time) of the oscillating actions (oscillating action mode 1, oscillating action mode 2) of the respective two oscillation cam faces are set approximately equal to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  Conventionally, for example, Patent Document 1 discloses a variable valve operating apparatus for an internal combustion engine in which a cam for lifting a valve (intake valve or exhaust valve) of the internal combustion engine is driven by a motor. In this conventional variable valve device, not only the forward rotation mode (rotation operation) in which the cam is continuously rotated in a constant direction (forward rotation direction) but also the forward / reverse rotation mode (oscillation) according to the operating state of the internal combustion engine. Operation) is executed.

  The forward / reverse rotation mode is an operation mode for switching the rotation direction of the motor at an arbitrary position while the valve is open. According to such a forward / reverse rotation mode (swinging operation), the swinging surface of the cam is repeatedly moved between the zero lift surface and the pressing surface within a range in which the valve pressed by the cam does not reach the maximum lift position. Can be operated as follows. Thereby, the lift amount (working angle) of the valve can be arbitrarily variably controlled.

JP 2004-183612 A

  A cam that drives a valve (an intake valve or an exhaust valve) has a plurality of swing cam surfaces including a zero lift surface and a pressing surface. Therefore, if the above-described rocking motion is performed using one rocking cam surface without any consideration, only one rocking cam surface will be worn away. become. When such uneven wear occurs, the valve lift amount during the swinging operation changes, and at the same time, there is a difference in the lift amount between the opening side and the closing side of the valve during the rotation operation, As a result, there is a difference in the intake air amount between the cylinders.

  The present invention has been made to solve the above-described problems, and can favorably vary the valve lift amount by using the swinging operation while suitably suppressing the change of the valve lift amount due to uneven wear of the cam. An object is to provide a variable valve operating apparatus for an internal combustion engine.

A first aspect of the present invention is a variable valve operating apparatus for an internal combustion engine capable of changing a lift amount of a valve by swinging a cam having a plurality of swing cam surfaces including a zero lift surface and a pressing surface by a motor.
Cam surface selecting means for selecting one swing cam surface to be used during the swing operation from among the plurality of swing cam surfaces when the swing operation is started;
The cam surface selecting means selects the one rocking cam surface to be controlled so that the plurality of rocking cam surfaces are used substantially equally.

Further, the second invention further comprises a deceleration request detection means for detecting a deceleration request of the vehicle in the first invention,
The cam surface selection means controls the swing cam surface that takes the shortest time to start the swing operation when the vehicle deceleration request is equal to or higher than a predetermined level when the swing operation is started. The single rocking cam surface to be selected is selected.

  According to a third aspect of the present invention, in the first or second aspect, the cam surface selecting means controls the control target so that the execution times of the swing motions for the plurality of swing cam surfaces are substantially equal. The one rocking cam surface is selected as follows.

  According to a fourth aspect of the present invention, in the first or second aspect of the invention, the cam surface selection means is configured to control the first surface to be controlled from the plurality of swing cam surfaces each time a swing operation is performed. One rocking cam surface is selected in order.

  According to a fifth aspect of the present invention, in any one of the first to third aspects, the cam surface selecting means is configured such that the operation ranges of the plurality of swing cam surfaces that are swinging are substantially equal. In addition, the one rocking cam surface to be controlled is selected.

  According to the first invention, when the swing operation is started, one swing cam surface to be controlled is selected so that the plurality of swing cam surfaces are used substantially evenly. become. For this reason, it can prevent suitably that only a specific rocking cam surface wears out. As a result, it is possible to satisfactorily execute the variable control of the valve lift amount using the swinging operation while suitably suppressing the change in the valve lift amount due to such uneven cam wear.

  According to the second aspect of the present invention, it is possible to ensure the responsiveness of the internal combustion engine by flexibly responding to a request for switching to an urgent swinging operation while suitably suppressing a change in the valve lift amount due to uneven wear of the cam. It can be realized together.

  According to the third invention, when the swing operation is started, one swing cam surface to be controlled so that the execution time of the swing operation for each of the plurality of swing cam surfaces becomes substantially equal. Is selected, the plurality of swing cam surfaces can be used substantially equally by a relatively simple method.

  According to the fourth invention, each time a swing operation is performed, one swing cam surface to be controlled is sequentially selected from a plurality of swing cam surfaces, so that it is a relatively simple method. Thus, the plurality of swing cam surfaces can be used substantially evenly.

  According to the fifth aspect of the present invention, the rocking cam surface is selected by selecting one rocking cam surface to be controlled so that the operation ranges of the plurality of rocking cam surfaces during the rocking motion are substantially equal. In consideration of the operating range of the cam surface, it is possible to suitably suppress only a specific portion of the plurality of swing cam surfaces from being worn away. Further, when combined with the third aspect of the invention, only specific portions of the plurality of swing cam surfaces are worn out in consideration of the operation range of the swing cam surfaces and the execution time of each operation range. Can be more suitably suppressed.

Embodiment 1 FIG.
[System configuration]
FIG. 1 is a diagram for explaining a configuration of an internal combustion engine 10 according to a first embodiment of the present invention. The system of this embodiment includes an internal combustion engine 10. Here, it is assumed that the internal combustion engine 10 is an in-line four-cylinder engine. A piston 12 is provided in the cylinder of the internal combustion engine 10. A combustion chamber 14 is formed in the cylinder of the internal combustion engine 10 on the top side of the piston 12. An intake passage 16 and an exhaust passage 18 communicate with the combustion chamber 14.

  An air flow meter 20 that outputs a signal corresponding to the flow rate of air sucked into the intake passage 16 is provided in the vicinity of the inlet of the intake passage 16. A throttle valve 22 is provided downstream of the air flow meter 20. The throttle valve 22 is an electronically controlled throttle valve that can control the throttle opening TA independently of the accelerator opening. In the vicinity of the throttle valve 22, a throttle sensor 24 for detecting the throttle opening degree TA is disposed.

  A fuel injection valve 26 for injecting fuel into the intake port of the internal combustion engine 10 is disposed downstream of the throttle valve 22. A spark plug 28 is attached to the cylinder head of the internal combustion engine 10 so as to protrude from the top of the combustion chamber 14 into the combustion chamber 14. The intake port and the exhaust port are respectively provided with an intake valve 30 and an exhaust valve 32 for bringing the combustion chamber 14 and the intake passage 16 or the combustion chamber 14 and the exhaust passage 18 into a conductive state or a cut-off state.

  The intake valve 30 and the exhaust valve 32 are driven by an intake variable valve mechanism 34 and an exhaust variable valve mechanism 36, respectively. The detailed configuration of these variable valve mechanisms 34 and 36 will be described later with reference to FIGS.

  The system shown in FIG. 1 includes an ECU (Electronic Control Unit) 40. In addition to the various sensors described above, the ECU 40 is connected to a crank angle sensor 42 that detects the engine speed and an accelerator opening sensor 44 that detects the accelerator opening PA. The ECU 40 is connected to the various actuators described above. The ECU 40 can control the operating state of the internal combustion engine 10 based on those sensor outputs.

[Configuration of Variable Valve Mechanism of this Embodiment]
FIG. 2 is a diagram showing the configuration of the intake variable valve mechanism 34 provided in the system shown in FIG. Hereinafter, the intake variable valve mechanism 34 will be further described with reference to FIG. The exhaust variable valve mechanism 36 has substantially the same configuration as the intake variable valve mechanism 34, and therefore detailed illustration and description thereof will be omitted.

  As shown in FIG. 2, the internal combustion engine 10 includes two intake valves 30 per cylinder. The internal combustion engine 10 includes the four cylinders (# 1 to # 4) as described above, and the explosion stroke is performed in the order of # 1 → # 3 → # 4 → # 2. The intake variable valve mechanism 34 includes two devices, that is, an intake variable valve mechanism 34A and an intake variable valve mechanism 34B. The intake variable valve mechanism 34A drives the intake valves 30 provided in the # 2 and # 3 cylinders, and the intake variable valve mechanism 34B drives the intake valves 30 provided in the # 1 and # 4 cylinders.

  The intake variable valve mechanism 34A includes an electric motor (hereinafter referred to as a motor) 50A as a drive source, a gear train 52A as a transmission mechanism that transmits the rotational motion of the motor 50A, and the rotational motion transmitted from the gear train. A camshaft 54A that converts the valve 30 into a linear opening / closing motion. Similarly, the intake variable valve mechanism 34B includes a motor 50B, a gear train 52B, and a camshaft 54B.

  The motors 50A and 50B are servo motors capable of controlling the rotation speed and the rotation amount. For example, a DC brushless motor or the like is preferably used as the motors 50A and 50B. The motors 50A and 50B incorporate rotation angle detection sensors such as a resolver and a rotary encoder for detecting the rotation position (rotation angle). The rotational speed and amount of rotation of the motors 50A and 50B are controlled by the ECU 40.

  A cam drive gear 56 that rotates integrally with the camshafts 54A and 54B and a cam 58 that also rotates integrally with the camshafts 54A and 54B are provided on the outer periphery of the camshafts 54A and 54B, respectively.

  The gear train 52A may be configured such that the rotation of the motor gear 62A attached to the output shaft 60 of the motor 50A causes the camshaft 54A to rotate at an equal speed via the intermediate gear 64A, with respect to the motor gear 62A. The cam drive gear 56 may be configured to increase or decrease speed. Similarly, the gear train 52B transmits the rotation of the motor gear 62B attached to the output shaft of the motor 50B to the cam drive gear 56 of the camshaft 54B via the intermediate gear 64B (not shown in FIG. 2).

  As shown in FIG. 2, the camshaft 54A is disposed above the intake valves 30 of the # 2 and # 3 cylinders, and the cams 58 provided on the camshaft 54A make the intake valves 30 of the # 2 and # 3 cylinders. It is opened and closed. The camshaft 54B is divided into two parts and is disposed on the upper part of the intake valves 30 of the # 1 and # 4 cylinders. The cam 58 provided on the camshaft 54B is used to intake the # 1 and # 4 cylinders. The valve 30 is driven to open and close. The camshaft 54B divided into two is connected via a connecting member inserted into the hollow camshaft 54A and is configured to rotate integrally.

  As shown in FIG. 2, a cam angle sensor 68A for detecting the rotational position of the camshaft 54A is disposed in the vicinity of the camshaft 54A. Similarly, a cam angle sensor 68B for detecting the rotational position of the camshaft 54B is disposed in the vicinity of the camshaft 54B.

  FIG. 3 is a schematic diagram showing how the intake valve 30 is driven by the cam 58. The cam 58 is formed as a kind of plate cam in which a part of a cylindrical zero lift surface 58a coaxial with the camshafts 54A and 54B is expanded radially outward to form a pressing surface (cam nose) 58b. The profile of the cam 58 is set so that a negative curvature does not occur over the entire circumference, that is, a convex curved surface is drawn outward in the radial direction.

  As shown in FIG. 2, each intake valve 30 includes a valve shaft 30a. Each cam 58 faces a valve lifter 66 provided at one end of the valve shaft 30 a of the intake valve 30. Each intake valve 30 is biased toward the cam 58 by a compression reaction force of a valve spring (not shown). When the zero lift surface 58a of the cam 58 faces the valve lifter 66, the intake valve 30 is brought into close contact with the valve seat (not shown) of the intake port by the urging force of the valve spring, and the intake port is closed.

  When the rotational motion of the motors 50A and 50B is transmitted to the camshafts 54A and 54B via the gear trains 52A and 52B, the cam 58 rotates integrally with the camshafts 54A and 54B, and the pressing surface 58b passes over the valve lifter 66. Then, the valve lifter 66 is pushed down, and the intake valve 30 lifts (opens) against the urging force of the valve spring.

  3A and 3B show two drive modes of the cam 58. FIG. In the drive mode of the cam 58, the motors 50A and 50B are continuously rotated in one direction to move the cam 58 to the maximum lift position, that is, the pressing surface 58b of the cam 58 is the other part (this component) (see FIG. 3A). In this case, the forward rotation drive mode in which the valve is lifted continuously beyond the position in contact with the valve lifter 66) in the forward rotation direction (the arrow direction in FIG. 3A), and the motor before reaching the maximum lift position in the forward rotation drive mode. There is a swing drive mode in which the cam 58 is reciprocated between the zero lift surface 58a and the pressing surface 58b as shown in FIG.

  In the normal rotation drive mode, the operating angle of the intake valve 30 is controlled by controlling the rotational speed of the cam 58. In the swing drive mode, the operating angle and the lift amount of the intake valve 30 can be variably controlled by controlling the angular range in which the cam 58 swings together with the rotational speed of the cam 58. Thus, according to the intake variable valve operating mechanism 34, it is possible to drive the intake valve 30 with the optimum operating angle and lift amount (valve opening characteristic) according to the operating state.

  FIG. 4 is a schematic diagram showing the relationship between the engine speed and torque (load) of the internal combustion engine 10 and the drive mode of the cam 58. As shown in FIG. 4, the drive mode of the cam 58 is selectively used in association with the engine speed and torque (load). Basically, the swing drive mode is selected in the low load and low rotation range, and the normal rotation drive mode is selected in the high load and high rotation range. As a result, control is performed to reduce the operating angle and lift amount of the intake valve 30 in the low load and low rotation range, and to increase the operating angle and lift amount of the intake valve 30 in the high load and high rotation range. It is possible to send an optimal amount of air corresponding to the amount of air into the cylinder.

  FIG. 5 is a schematic diagram showing in detail two cams 58 provided on the camshaft 54A. As shown in FIG. 5, on the camshaft 54A, the cam 58 for driving the intake valve 30 for the # 2 cylinder and the cam 58 for driving the intake valve 30 for the # 3 cylinder are at an angular position of 180 °. Are spaced apart. In the four-cylinder internal combustion engine, the explosion strokes are performed in the order of # 1, # 3, # 4, and # 2 during the crank angle of 720 °. Therefore, the intake stroke of the # 2 cylinder and the # 3 cylinder is 360 ° of the crank angle. Done every time. In the intake variable valve mechanism 34A, the # 2 cylinder cam 58 and the # 3 cylinder cam 58 alternately drive the # 2 cylinder intake valve 30 and the # 3 cylinder intake valve 30 at every 360 ° crank angle. Then, the camshaft 54A is rotated or swung. Similarly, the camshaft 54B is provided with a cam 58 for driving the intake valves 30 of the # 1 cylinder and # 4 cylinder, and the intake variable valve mechanism 34B rotates or swings the camshaft 54B. Thus, the intake valve 30 of the # 1 cylinder and the intake valve 30 of the # 4 cylinder are driven.

  According to the system of the present embodiment configured as described above, in the normal rotation drive mode, the rotation speed of the cam 58 is changed during one rotation of the cam 58, and the cam 58 lifts the intake valve 30. The operating angle of the intake valve 30 can be changed by changing the rotational speeds of the motors 50A and 50B so that. In the normal rotation drive mode, the target operating angle of the intake valve 30 is set in the ECU 40 according to the operating state of the internal combustion engine 10. The ECU 40 controls the operation of the motors 50A and 50B so that the rotational speeds of the motors 50A and 50B corresponding to the target operating angles can be realized.

  In the swing drive mode, the operation of the intake valve 30 is performed by changing the rotation speed and rotation amount of the motors 50A and 50B so that the rotation speed of the cam 58 and the angle range in which the cam 58 swings are changed. The angle and maximum lift can be changed. In the swing drive mode, the target operating angle and the target maximum lift amount of the intake valve 30 are set in the ECU 40 according to the operating state of the internal combustion engine 10. The ECU 40 controls the operation of the motors 50A and 50B so that the rotation amounts and rotation speeds of the motors 50A and 50B corresponding to the target operating angle and the target maximum lift amount can be realized.

[Characteristics of Embodiment 1]
FIG. 6 is a diagram for explaining characteristic control in the present embodiment. More specifically, FIG. 6A shows the control referred to for comparison with the control of the system of this embodiment, and FIG. 6B shows the control of the system of this embodiment. Yes. In addition, the variable valve mechanism applied to the control referred for this contrast shall have the same structure as the intake variable valve mechanism 34 of this embodiment. FIG. 6 is a view of the camshaft (54A) shared by the # 2 cylinder and the # 3 cylinder as viewed from the axial direction thereof. Here, the camshaft (54A) will be described as a representative, but the same applies to the camshaft (54B) shared by the # 1 cylinder and the # 4 cylinder.

  The cams 58 of the # 2 and # 3 cylinders are fixed to the camshaft 54A with the cam nose 58 (pressing surface) b shifted by 180 °. In this case, there are two swing cam surfaces (that is, the zero lift surface 58a and the pressing surface 58b) that can perform the swing operation for each cam 58.

  For comparison, the control shown in FIG. 6 (A) does not give any consideration to the swing cam surface that performs the swing operation. Therefore, during the swing operation, one of the swing cam surfaces ( The swing cam surface indicated by a circle in FIG. 6A is used in a biased manner.

  If such a biased use is performed over a long period of time, the wear of only the rocking cam surface on the used side will progress. When such uneven wear occurs, the valve lift amount during the swinging operation changes, and at the same time, there is a difference in the valve lift amount between the opening side and the closing side during the rotation operation. As a result, a difference occurs in the intake air amount between the cylinders. Such a difference in the intake air amount causes variations in combustion among the cylinders.

  Therefore, in this embodiment, when starting the swing operation, more specifically, the two swing cam surfaces are used approximately equally, as shown in FIG. The two swing cam surfaces are selected so that the execution time of the swing operation mode 1 and the execution time of the swing operation mode 2 are substantially equal. Here, the swinging operation performed using one of the two swing cam surfaces is referred to as “swing operation mode 1”, and the other swing cam surface is used. The swing operation is referred to as “swing operation mode 2”.

  Further, in the present embodiment, the above-described swing cam surface is selected when the vehicle is required to accelerate rapidly after considering the above-mentioned uneven wear on the two swing cam surfaces. Is temporarily stopped, and the rocking cam surface that can be switched to the rocking motion at the highest speed is selected as the rocking cam surface to be controlled.

  FIG. 7 is a flowchart of a routine executed by the ECU 40 in order to realize the above function. In the routine shown in FIG. 7, it is first determined whether or not there is a swing operation start command for the intake variable valve mechanism 34 (step 100). The start command of the swing operation (swing drive mode) is a command issued when switching from the rotation operation (forward drive mode) to the swing operation or at the start of the internal combustion engine 10. The presence / absence of the command is determined based on the operating state of the internal combustion engine 10 such as the number and load.

  If it is determined in step 100 that there is a swing operation start command, it is then determined whether or not the swing motion needs to be executed immediately (step 102). For example, when it is recognized that the deceleration request of the vehicle is higher than a predetermined level, such as when the accelerator pedal is suddenly returned by the driver of the vehicle, the swinging operation is performed immediately. It is judged that the situation is necessary.

  If it is determined in step 102 that it is not necessary to immediately perform the swing motion, the use operation mode determination is performed (step 104). More specifically, in this step 104, the integrated values of the respective execution times of the swing operation mode 1 and the swing operation mode 2 until the previous swing operation execution are referred to, and the execution time up to the present time is determined. It is determined which of the shorter swinging operation modes is. Then, the corresponding mode is specified as the swing operation mode used this time.

  Next, a switching determination angle (cam angle) is calculated (step 106). In the system of the present embodiment, a switching determination angle for switching from the rotation operation to the swing operation is set in advance for each of the two swing cam surfaces. In this step 106, more specifically, the switching determination angle corresponding to the current use operation mode specified in the above step 104 is calculated.

  When it is determined in step 102 that it is a situation where it is necessary to perform the swinging operation immediately, that is, it can be determined that priority should be given to ensuring the responsiveness of the internal combustion engine 10 based on the sudden deceleration request. Next, the shortest switching determination angle is calculated (step 108). More specifically, in this step 108, the switching determination angle for the rocking cam surface having the smaller angle difference from the current cam angle to the switching determination angle (in other words, the rocking operation mode) is calculated.

  In the routine shown in FIG. 7, it is next determined whether or not the current cam angle has reached the switching determination angle calculated in step 106 or 108 (step 110). As a result, if it is determined that the current cam angle has reached such a switching determination angle, the swing operation using the swing cam surface that has reached the switching determination angle (swing drive mode) Is started (step 112).

  According to the routine shown in FIG. 7 described above, when a swing operation start request is made, the two swing cam surfaces (zero lift) are based on the execution times of the swing operation modes 1 and 2 until the previous time. One rocking cam surface to be controlled is selected from the two rocking cam surfaces so that the surface 58a and the pressing surface 58b) are used substantially equally. For this reason, it can prevent suitably that only one rocking cam surface wears out by a comparatively simple method. As a result, it is possible to satisfactorily execute the variable control of the valve lift amount using the swinging operation while suitably suppressing the change in the valve lift amount due to such uneven cam wear.

  Further, according to the above routine, when a high-level deceleration request is issued to the vehicle, the swing cam surface that can start the swing operation in the shortest time is selected. The uneven wear of the rocking cam surface itself is the result of long-term use. In the above routine, basically, as described above, consideration is given so that each rocking cam surface is used approximately evenly. Therefore, such an exceptional measure is rarely taken when a sudden deceleration is requested. It can be said that there is no problem. As described above, according to the above routine, it is possible to flexibly respond to a request for switching to an urgent swinging operation, and to ensure the responsiveness of the internal combustion engine 10 together.

  By the way, in Embodiment 1 mentioned above, the integrated value of each execution time of the rocking | fluctuation operation mode 1 regarding two rocking cam surfaces and the rocking | fluctuation operation mode 2 are compared, and each rocking | fluctuation operation mode 1, By making the execution times of 2 approximately equal, the two rocking cam surfaces are used substantially evenly. However, in the present invention, the specific method for making the two rocking cam surfaces be used substantially equally is not limited to this, and for example, the following method may be used. Good.

  That is, as the simplest method, the swing cam surface (swing operation modes 1 and 2) to be used for each start request of the swing operation may be switched alternately (in order). Furthermore, the number of executions of the swing operation (swing drive mode) for each swing cam surface may be made uniform.

  As another suitable method, an operation range of the swing cam surface when the swing operation is performed may be considered. The operating range of the swing cam surface during the swing operation varies depending on the valve lift amount required from the internal combustion engine 10 side. More specifically, when the required valve lift amount is high, the operating range of the swing cam surface (in other words, the swing amount of the cam and the valve lift amount) becomes wider. Therefore, the operating ranges for the respective swing cam surfaces may be made uniform based on the history of the operation range up to the present for each swing cam surface. For example, when there is a history that one rocking cam surface is used in a relatively narrow operating range and the other rocking cam surface is used in a relatively wide operating range, When the lift amount is requested, the one swing cam surface is selected. According to the method as described above, it is possible to suitably suppress uneven wear of only specific portions of the plurality of swing cam surfaces in consideration of the operation range of the swing cam surfaces.

  As another suitable method, the execution time of each of the swing operation modes 1 and 2 may be measured for each operation range during the swing operation. Then, in addition to the operation range for each swing cam surface during the swing operation, the swing cam surface used for the next swing operation request based on the execution time of each swing operation mode 1 and 2 for each operation range. May be selected. For example, if the current operating range of each rocking cam surface used up to now is about the same, the history of use in that operating range will be the next swinging operation that requires that operating range. Select the shorter oscillating cam surface. According to the method as described above, it is further preferable that only a specific part of the plurality of swing cam surfaces is worn out in consideration of the operation range of the swing cam surface and the execution time of each operation range. Can be suppressed.

In the first embodiment described above, the “cam surface selection means” according to the first aspect of the present invention is realized by the ECU 40 executing the processing of steps 102 to 106.
Further, the “deceleration request detecting means” in the second aspect of the present invention is realized by the ECU 40 executing the processing of steps 102 and 108 described above.

It is a figure for demonstrating the structure of the internal combustion engine of Embodiment 1 of this invention. It is a figure which shows the structure of the intake variable valve mechanism with which the system shown in FIG. 1 is provided. It is a schematic diagram which shows a mode that an intake valve is driven with a cam. It is a schematic diagram which shows the relationship between the engine speed of an internal combustion engine, torque (load), and the drive mode of a cam. It is a schematic diagram which shows in detail the two cams provided in the cam shaft. It is a figure for demonstrating the characteristic control in Embodiment 1 of this invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 30 Intake valve 32 Exhaust valve 34A, 34B Intake variable valve mechanism 36 Exhaust variable valve mechanism 40 ECU (Electronic Control Unit)
44 Accelerator opening sensors 50A, 50B Motors 54A, 54B Camshaft 58 Cam 58a Zero lift surface 58b Press surface 68A, 68B Cam angle sensor

Claims (5)

A variable valve operating apparatus for an internal combustion engine capable of changing a lift amount of a valve by swinging a cam having a plurality of swing cam surfaces including a zero lift surface and a pressing surface by a motor,
Cam surface selecting means for selecting one swing cam surface to be used during the swing operation from among the plurality of swing cam surfaces when the swing operation is started;
The variable valve operating device for an internal combustion engine, wherein the cam surface selecting means selects the one rocking cam surface to be controlled so that the plurality of rocking cam surfaces are used substantially equally. . Further comprising a deceleration request detecting means for detecting a deceleration request of the vehicle;
The cam surface selection means controls the swing cam surface that takes the shortest time to start the swing operation when the vehicle deceleration request is equal to or higher than a predetermined level when the swing operation is started. 2. A variable valve operating apparatus for an internal combustion engine according to claim 1, wherein said variable rocking device is selected as said one rocking cam surface.   The cam surface selection means selects the one rocking cam surface to be controlled so that the execution time of the rocking motion for each of the plurality of rocking cam surfaces is substantially equal. The variable valve operating apparatus for an internal combustion engine according to claim 1 or 2.   2. The cam surface selecting means sequentially selects the one rocking cam surface to be controlled from the plurality of rocking cam surfaces each time a rocking operation is performed. Or the variable valve operating apparatus of the internal combustion engine of 2.   The cam surface selecting means selects the one rocking cam surface to be controlled so that the operation range of each of the plurality of rocking cam surfaces during the rocking operation is substantially equal. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 3.

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