JP2008291708A - Valve moving system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for uniquely specifying a cam rotation position regardless of a cam position sensor, in a valve operating system for rotary drive of a cam by a driving source independent of an internal combustion engine. <P>SOLUTION: In a valve operating system for an internal combustion engine for rotary drive of a cam by a driving source independent of an internal combustion engine, a cam is rotated by the driving source at the time of starting the internal combustion engine, and the cam rotation position is determined based on the required driving torque of the driving source at the time. In the case of rotary drive of a cam having a plurality of cylinders by one driving source, a valve operating mechanism is configured so that the required driving torque necessary for lifting a valve with the cam of a specific cylinder out of the plurality of the cylinders is different from those of the other cylinders. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve operating system that rotates or swings a cam by a drive source independent of an internal combustion engine.

  There has been proposed a valve operating system in which a cam is rotationally driven by a drive source independent of an internal combustion engine. In such a valve operating system, since the cam is not mechanically linked to the engine output shaft (crankshaft), it is necessary to adapt the rotational position (phase) of the cam relative to the crankshaft to the combustion cycle of the internal combustion engine.

In order to adapt the rotational position of the cam relative to the crankshaft to the combustion cycle of the internal combustion engine, it is essential to accurately grasp the rotational position of the cam when the internal combustion engine is started. For this reason, a technique for storing the stop position of the cam in the nonvolatile memory when the operation of the internal combustion engine is stopped has been proposed (for example, see Patent Document 1).
JP 2004-183612 A JP 2004-183610 A

  By the way, depending on the stop position of the cam, the position of the cam may change while the operation of the internal combustion engine is stopped. For example, when the cam stops at a position where the lift amount of the valve becomes relatively large, the cam may rotate due to the reaction force of the valve spring while the operation of the internal combustion engine is stopped.

  On the other hand, a method of attaching a cam position sensor capable of detecting the rotational position of the cam to the internal combustion engine is conceivable. However, when a plurality of cams are rotated or rocked by different driving sources, a plurality of cam position sensors are required. Therefore, there is a possibility that the number of parts increases and the manufacturing cost increases.

  The present invention has been made in view of various circumstances as described above, and an object of the present invention is to depend on a cam position sensor in a valve operating system that rotates or swings a cam by a drive source independent of an internal combustion engine. The present invention provides a technique capable of uniquely specifying the rotational position of the cam without any problem.

  In order to solve the above-described problems, the present invention provides a valve operating system for an internal combustion engine in which a cam is rotated or rocked by a drive source independent of the internal combustion engine, and the cam is rotated by the drive source when the internal combustion engine is started. The rotational position of the cam is determined based on the required drive torque of the drive source at that time.

  Specifically, in the present invention, in a valve operating system for an internal combustion engine that rotates or swings a cam by a drive source independent of the internal combustion engine, a control unit that rotates the cam by the drive source when the internal combustion engine is started, And determining means for determining the rotational position of the cam based on the required drive torque of the drive source when the control means is rotating the cam.

The required drive torque of the drive source when the cam is rotating is substantially constant when the lift amount of the valve driven to open and close by the cam becomes zero, but from the constant value when the valve starts to lift. To increase. The increase amount at that time increases as the lift amount of the bubble increases, and reaches a peak when the lift amount of the valve reaches a substantially maximum lift amount. Thereafter, the required drive torque of the drive source drops below the certain value and then returns to the certain value.

  Therefore, when the internal combustion engine is started, the cam is rotated by the drive source, the timing at which the required drive torque of the drive source starts to increase from the above-described constant value, the timing at which the required drive torque of the drive source reaches a peak, or the required drive of the drive source The rotational position (phase) of the cam can be specified by detecting the timing at which the torque returns from the lower value to the fixed value (hereinafter, these timings are referred to as “singular timings”).

  As a result, the rotational position (phase) of the cam can be specified without depending on the cam position sensor.

  When one drive source rotationally drives the cams of a plurality of cylinders, it cannot be specified which of the cylinders has such a unique timing as described above. Therefore, when a single drive source rotationally drives the cams of multiple cylinders, the required drive torque when the cam of a specific cylinder lifts the valve is the required drive when the cam of another cylinder lifts the valve. The valve operating mechanism for each cylinder may be configured differently from the torque.

  According to such a configuration, the timing at which the cam of the specific cylinder lifts the valve can be specified based on the required drive torque of the drive source. As a result, the rotational position (phase) of the cams of the plurality of cylinders can be determined. The valve operating mechanism here is a mechanism including at least a valve and a valve spring.

  As a method of making the required drive torque when the cam of the specific cylinder lifts the valve different from the required drive torque when the cam of the other cylinder lifts the valve, the spring constant of the valve spring of the specific cylinder is set to the other cylinder. A method of making it different from the spring constant of the valve spring can be exemplified.

  Since the valve spring acts as a reaction force when the cam lifts the valve, if the spring constant of the valve spring of a specific cylinder is different from that of other cylinders, the required drive of the drive source when the cam of the specific cylinder lifts the valve The torque is different from that when the cam of the other cylinder lifts the valve.

  Also, in the valve operating mechanism having a reduction mechanism that reduces the reaction force generated when the cam of each cylinder lifts the valve, the reduction torque generated by the reduction mechanism when the cam of the specific cylinder lifts the valve is different. The torque reduction mechanism may be configured to be different from the reduction torque generated by the reduction mechanism when the cylinder cam lifts the valve.

  According to such a configuration, the magnitude of the reaction force when the cam of the specific cylinder lifts the valve is different from the magnitude of the reaction force when the cam of the other cylinder lifts the valve. As a result, the required drive torque of the drive source when the cam of the specific cylinder lifts the valve is different from the required drive torque of the drive source when the cam of the other cylinder lifts the valve.

  In addition, an electric motor can be illustrated as a drive source concerning this invention. In that case, the current value or voltage value applied to the motor correlates with the required drive torque of the motor.

  The reduction mechanism according to the present invention includes a cam that rotates in conjunction with a valve opening / closing cam (hereinafter referred to as “torque reduction cam”) and a spring that applies a reaction force to the torque reduction cam (hereinafter referred to as “torque reduction cam”). A mechanism provided with a “spring for torque reduction” can be exemplified.

At this time, the profile of the torque reduction cam is such that when the valve spring is extended (when the lift amount of the valve is zero), the torque reduction spring is contracted and when the valve spring is contracted (when the valve is lifted) ) Is formed such that the torque reducing spring extends. According to this configuration, the reaction force of the valve spring generated when the cam lifts the valve is offset by the torque reduction spring, so that the required drive torque applied to the drive source can be reduced.

  In the torque reduction mechanism configured as described above, the cam profile of the torque reduction cam when the cam of the specific cylinder lifts the valve, and the cam profile of the torque reduction cam when the cam of the other cylinder lifts the valve. You can make it different.

  According to the present invention, in a valve operating system that rotates or swings a cam by a drive source independent of the internal combustion engine, the rotational position of the cam can be uniquely specified without depending on the cam position sensor.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

<Example 1>
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a schematic configuration of a valve operating system for an internal combustion engine according to the present invention.

  The internal combustion engine 1 shown in FIG. 1 is a 4-stroke cycle spark ignition internal combustion engine (gasoline engine). The internal combustion engine 1 includes four cylinders 2. A piston 3 is slidably mounted in the cylinder 2. The piston 3 is connected to the crankshaft 5 via a connecting rod 4.

  The inside of the cylinder 2 communicates with the intake port 6 and the exhaust port 7. The opening end of the intake port 6 in the cylinder 2 is opened and closed by an intake valve 8. An open end of the exhaust port 7 in the cylinder 2 is opened and closed by an exhaust valve 9. The intake valve 8 and the exhaust valve 9 are respectively opened and closed by an intake side drive mechanism 10 and an exhaust side drive mechanism 11.

  The intake port 6 communicates with the intake passage 60. A fuel injection valve 12 is attached to the intake passage 60. The intake air flowing through the intake passage 60 is guided to the intake port 6. The intake air guided to the intake port 6 is sucked into the cylinder 2 when the intake valve 8 is opened. At that time, the fuel injected from the fuel injection valve 12 to the intake port 6 is also taken into the cylinder 2 together with the intake air.

  The fuel and the intake air (air mixture) guided into the cylinder 2 are burned using the spark generated by the spark plug 13 as a spark. Gas burned in the cylinder 2 (burned gas) is discharged to the exhaust port 7 when the exhaust valve 9 is opened. The exhaust port 7 communicates with the exhaust passage 70, and the burnt gas described above is discharged from the exhaust port 7 into the atmosphere through the exhaust passage 70.

  The internal combustion engine 1 configured as described above is provided with an ECU 14. The ECU 14 is an electronic control unit that includes a CPU, a ROM, a RAM, a backup RAM, and the like. The ECU 14 is electrically connected to various sensors such as a crank position sensor 15, a water temperature sensor 16, and an ignition switch 17.

  The ECU 14 electrically controls the fuel injection valve 12, the spark plug 13, the intake side drive mechanism 10, and the exhaust side drive mechanism 11 based on the measurement values of the various sensors described above.

  Here, the configuration of the intake side drive mechanism 10 and the exhaust side drive mechanism 11 will be described with reference to FIGS. FIG. 2 is a diagram showing the configuration of the intake side drive mechanism 10. 2 represent the first to fourth cylinders of the internal combustion engine 1, respectively. The order of combustion from the first cylinder (# 1) to the fourth cylinder (# 4) is as follows: first cylinder (# 1) → third cylinder (# 3) → fourth cylinder (# 4) → second cylinder ( # 2).

  Two intake valves 8 are provided in each of the first cylinder (# 1) to the fourth cylinder (# 4). A valve lifter 80 is attached to the stem base end of the intake valve 8. The intake valve 8 is urged in the valve closing direction by an intake side valve spring 88, and the valve lifter 80 is pressed against the first intake cam 81 or the second intake cam 82 by the urging force.

  The first intake cam 81 is a cam that opens and closes the intake valves 8 of the first cylinder (# 1) and the fourth cylinder (# 4), and is fixed to the first intake camshaft 83. The second intake cam 82 is a cam that opens and closes the intake valves 8 of the second cylinder (# 2) and the third cylinder (# 3), and is fixed to the second intake camshaft 84. That is, in this embodiment, two cylinders having different combustion timings are configured to share one intake camshaft.

  The first intake camshaft 83 and the second intake camshaft 84 are arranged coaxially and are supported by the internal combustion engine 1 so as to be rotatable or swingable in the circumferential direction independently of each other.

  A first driven gear 85 is fixed to one end of the first intake camshaft 83. The first driven gear 85 meshes with the first output gear 19 fixed to the output shaft of the first motor 18. Hereinafter, the first driven gear 85 and the first output gear 19 are collectively referred to as a first reduction mechanism.

  In this case, the rotational torque of the first motor 18 is transmitted to the first intake camshaft 83 via the first reduction mechanism. Therefore, the first motor 18 can rotate or swing the first intake camshaft 83 in the circumferential direction via the first reduction mechanism.

  A second driven gear 86 is coaxially fixed to a part of the outer peripheral surface of the second intake camshaft 84. The second driven gear 86 is meshed with the intermediate gear 87. The intermediate gear 87 meshes with the second output gear 22 fixed to the output shaft of the second motor 21. Hereinafter, the second driven gear 86, the intermediate gear 87, and the second output gear 22 are collectively referred to as a second reduction mechanism. It is assumed that the reduction ratio by the second reduction mechanism is equivalent to that of the first reduction mechanism described above.

  In this case, the rotational torque of the second motor 21 is transmitted to the second intake camshaft 84 via the second reduction mechanism. Therefore, the second motor 21 can rotate or swing the second intake camshaft 84 in the circumferential direction via the second reduction mechanism.

  The first motor 18 includes a first resolver 20 that detects a rotation angle (phase) of the output shaft, and a detection signal of the first resolver 20 is input to the ECU 14. The second motor 21 includes a second resolver 23 that detects the rotation angle of the output shaft, and a detection signal of the second resolver 23 is input to the ECU 14.

  Next, FIG. 3 is a diagram showing a configuration of the exhaust side drive mechanism 11. In FIG. 3, two exhaust valves 9 are provided in each of the first cylinder (# 1) to the fourth cylinder (# 4). A valve lifter 90 is attached to the stem base end of the exhaust valve 9. The exhaust valve 9 is urged in the valve closing direction by an exhaust side valve spring 94, and the valve lifter 90 is pressed against the exhaust cam 91 by the urging force.

  The exhaust cams 91 of the first cylinder (# 1) to the fourth cylinder (# 4) are fixed to one exhaust camshaft 92. A third driven gear 93 is fixed to one end of the exhaust camshaft 92. The third driven gear 93 meshes with the third output gear 25 attached to the output shaft of the third motor 24. Hereinafter, the third driven gear 93 and the third output gear 25 are collectively referred to as a third reduction mechanism.

  In this case, the rotational torque of the third motor 24 is transmitted to the exhaust camshaft 92 via the third output gear 25 and the third driven gear 93. Therefore, the third motor 24 can rotate or swing the exhaust camshaft 92 in the circumferential direction via the third reduction mechanism.

  The third motor 24 includes a third resolver 26 that detects the rotation angle (phase) of the output shaft, and a detection signal of the third resolver 26 is input to the ECU 14.

  In the valve train configured as described above, the ECU 14 rotates or swings the first motor 18, the second motor 21, and the third motor 24 at the timing synchronized with the rotation of the crankshaft 5. The timing at which the intake valve 8 and the exhaust valve 9 of the cylinder (# 1) to the fourth cylinder (# 4) are synchronized with the rotation of the crankshaft 5 (that is, the first cylinder (# 1) to the fourth cylinder (# 4)). It can be opened and closed at a timing synchronized with the combustion cycle.

  Incidentally, in order for the ECU 14 to open and close the intake valves 8 and the exhaust valves 9 of all the cylinders at a timing synchronized with the rotation of the crankshaft 5, the first intake cam 81 (the first intake camshaft 83) is started when the internal combustion engine 1 is started. ), The rotational positions (phases) of the second intake cam 82 (second intake camshaft 84) and the exhaust cam 91 (exhaust camshaft 92) must be detected.

  As a method of detecting the rotational position of each camshaft, a method of attaching a cam position sensor to each camshaft is conceivable, but a plurality of cam position sensors must be attached, and the structure becomes complicated due to an increase in the number of parts. Increase manufacturing costs.

  Therefore, in the valve operating system for the internal combustion engine of the present embodiment, each camshaft is rotated by each motor when the internal combustion engine 1 is started, and the rotational position of each camshaft is determined based on the required drive torque of each motor at that time. I tried to do it. Hereinafter, a method for determining the rotational position of the camshaft based on the required drive torque of the motor will be described.

  FIG. 4 is a diagram showing the relationship between the rotational position (phase) of the cam and the required drive torque of the motor.

  In FIG. 4, the required drive torque of the motor is the reference torque T0 when the valve is not lifted. When the valve starts to lift, the required drive torque of the motor increases from the reference torque T0. The amount of increase at this time increases as the lift amount of the valve increases, and reaches a peak when the lift amount of the valve becomes substantially the maximum lift amount. Thereafter, the required drive torque of the motor returns to the reference torque T0 after becoming lower than the reference torque T0.

  In view of the above characteristics, the timing at which the required driving torque of the motor starts to increase from the reference torque T0, the timing at which the required driving torque of the motor reaches a peak, or the value from which the required driving torque of the motor is lower than the reference torque T0 The rotational position of the cam (camshaft) can be specified by detecting the singular timing such as the timing of returning to the torque T0.

By the way, in the valve operating system of the present embodiment, each of the first motor 18, the second motor 21, and the third motor 24 is configured to rotationally drive the cams of the plurality of cylinders 2. For this reason, it cannot be determined which cam of which cylinder 2 the above-mentioned singular timing is caused.

  On the other hand, in this embodiment, among the cams of a plurality of cylinders that are rotationally driven by a single motor, the required drive torque of the motor when the cam of the specific cylinder lifts the valve is different from that of the other cylinders. A valve mechanism was constructed.

  Specifically, the spring constant of the valve spring of a specific cylinder is made larger or smaller than the spring constant of the valve spring of another cylinder. In this case, the required drive torque of the motor when the cam of the specific cylinder lifts the valve is different from that when the cam of the other cylinder lifts the valve.

  FIG. 5 shows the required drive torque of the first motor 18 when the spring constant of the intake side valve spring 88 of the fourth cylinder (# 4) is made higher than the spring constant of the intake side valve spring 88 of the first cylinder (# 1). FIG.

  When the spring constant of the intake side valve spring 88 of the fourth cylinder (# 4) is higher than the spring constant of the intake side valve spring 88 of the first cylinder (# 1), the intake valve 8 of the fourth cylinder (# 4) is The reaction force of the intake side valve spring 88 generated when the intake side is lifted is larger than the reaction force of the intake side valve spring 88 generated when the intake valve 8 of the first cylinder (# 1) is lifted.

  For this reason, the peak Tmax4 of the driving torque required when the first intake cam 81 of the fourth cylinder (# 4) lifts the intake valve 8 is taken in by the first intake cam 81 of the first cylinder (# 1). It becomes larger than the peak Tmax1 of the driving torque required when the valve 8 is lifted.

  Therefore, the ECU 14 rotates the first intake camshaft 83 by the first motor 18 when the internal combustion engine 1 is started, and detects the timing at which the required drive torque of the first motor 18 at that time indicates Tmax4. The rotational position of the first intake camshaft 83 (in other words, the phase of the first intake cam 81 of the first cylinder (# 1) and the first intake cam 81 of the fourth cylinder (# 4)) can be determined. .

  Also for the second intake camshaft 84, the second intake cam of the second cylinder (# 2) is made different from the spring constant of the intake side valve spring 88 of the second cylinder (# 2) and the third cylinder (# 3). 82 and the phase of the second intake cam 82 of the third cylinder (# 3) can be discriminated.

  As for the exhaust camshaft 92, the spring constant of the exhaust side valve spring 94 of one cylinder (specific cylinder) of the first cylinder (# 1) to the fourth cylinder (# 4) is different from that of the other three cylinders. As a result, the phases of the exhaust cams 91 of the first cylinder (# 1) to the fourth cylinder (# 4) can be determined.

  Therefore, according to the valve operating system of the internal combustion engine according to the present embodiment, the rotational position of each camshaft (in other words, the phase of the intake and exhaust valves of each cylinder) is determined without attaching a cam position sensor to each camshaft. It becomes possible to do. As a result, it is possible to suppress complication of the structure and increase in manufacturing cost due to an increase in the number of parts.

<Example 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, a configuration different from that of the first embodiment will be described, and description of the same configuration will be omitted.

  In the first embodiment described above, an example in which the spring constant of a valve spring of a specific cylinder is made different from the spring constant of a valve spring of another cylinder has been described, but in this embodiment, when the cam of a specific cylinder lifts the valve, An example in which the reduced torque is made different from the reduced torque when the cam of the other cylinder lifts the valve will be described.

  FIG. 6 is a diagram showing a configuration of the exhaust side drive mechanism 11 in the present embodiment. A torque reduction mechanism 100 is attached to the exhaust side drive mechanism 11 of the present embodiment. This torque reduction mechanism 100 is a torque for reducing the reaction force of the exhaust side valve spring 94 that is generated when the exhaust cam 91 of the first cylinder (# 1) to the fourth cylinder (# 4) lifts the exhaust valve 9. This is a mechanism for generating (reduced torque).

  For example, as shown in FIG. 7, the torque reduction mechanism 100 is fixed to an exhaust camshaft 92 and rotates in conjunction with the exhaust camshaft 92, and the torque reduction cam 101 and the lifter 102. And a torque reducing spring 103 that generates an urging force that contacts the exhaust valve spring 94 and faces the exhaust side valve spring 94.

  The above-described profile of the torque reducing cam 101 is such that when the exhaust side valve spring 94 of each cylinder extends (in other words, when the exhaust cam 91 of each cylinder does not lift the exhaust valve 9), the torque reducing spring 103 is provided. When the exhaust side valve spring 94 of each cylinder contracts (in other words, when the exhaust cam 91 of each cylinder lifts the exhaust valve 9), the torque reducing spring 103 is formed to extend. .

  In the present embodiment, since the phases of the exhaust cams 91 of the first cylinder (# 1) to the fourth cylinder (# 4) are shifted from each other by 90 degrees, the profile of the torque reducing cam 101 is the torque every 90 degrees. The reduction spring 103 is formed to contract.

  As shown in FIG. 8, the torque reduction mechanism 100 configured in this manner generates torque having a phase opposite to that of the reaction force of the exhaust valve spring 94 of each cylinder. As a result, the required drive torque of the third motor 24 converges to the reference torque T0 regardless of the lift amount of the exhaust valve 9.

  On the other hand, a reduction torque when the exhaust cam 91 of one cylinder (specific cylinder) among the first cylinder (# 1) to the fourth cylinder (# 4) lifts the exhaust valve 9 is reduced by the exhaust cam 91 of the other cylinders. When the cam profile of the torque reducing cam 101 is formed, which is different from the reduced torque when the exhaust valve 9 is lifted, the required drive torque of the third motor 24 is that the exhaust cam 91 of the specific cylinder lifts the exhaust valve 9. When it is made to deviate from the reference torque T0.

  Specifically, as shown in FIG. 9, the shape of one cam nose among the four cam noses (cam lobes) of the torque reduction cam 101 may be different from the other. In this case, as shown in FIG. 10, the reduction torque when the exhaust cam 91 of the specific cylinder lifts the exhaust valve 9 is different from that of the other cylinders. As a result, when the exhaust cam 91 of the specific cylinder lifts the exhaust valve 9, the required drive torque of the third motor 24 deviates from the reference torque T0.

  Accordingly, the ECU 14 rotates the exhaust camshaft 92 by the third motor 24 when the internal combustion engine 1 is started, and detects the timing at which the required drive torque of the third motor 24 deviates from the reference torque T0 at that time. The rotational position of the exhaust cam 91 (in other words, the phase of the exhaust cam 91 of the first cylinder (# 1) to the fourth cylinder (# 4)) can be determined.

Note that the first intake camshaft 83 and the second intake camshaft 84 have different reduction torques when the intake cams of the two cylinders lift the intake valve 8, thereby making the first intake camshaft 83 and the second intake camshaft 83 different. 2 The rotational position of the intake camshaft 84 can be determined.

  Therefore, according to this embodiment, in the valve operating system of the internal combustion engine provided with the torque reduction mechanism, the rotational position of each camshaft (in other words, the intake and exhaust of each cylinder) without attaching a cam position sensor to each camshaft. It is possible to determine the phase of the valve. As a result, it is possible to obtain the same effect as that of the first embodiment described above.

  In the first and second embodiments described above, a four-cylinder spark ignition internal combustion engine has been described as an example. However, the number of cylinders, the arrangement of the cylinders, the method of igniting the air-fuel mixture, and the like are not limited thereto. Of course. Further, the number of intake camshafts and exhaust camshafts and the number of cams attached to each camshaft are not limited to this embodiment.

It is a figure which shows schematic structure of the valve operating system of the internal combustion engine in a 1st Example. It is a figure which shows the structure of the intake side drive mechanism in a 1st Example. It is a figure which shows the structure of the exhaust side drive mechanism in a 1st Example. It is a figure which shows the relationship between the rotational position (phase) of a cam, and the request drive torque of a motor. It is a figure which shows the required drive torque of a 1st motor at the time of making the spring constant of the intake side valve spring of the 4th cylinder (# 4) higher than the spring constant of the intake side valve spring of the 1st cylinder (# 1). It is a figure which shows the structure of the exhaust side drive mechanism in a 2nd Example. It is a figure which shows the 1st structure of a torque reduction mechanism. It is a figure which shows the relationship between the urging | biasing force of a valve spring and the reduction torque of a torque reduction mechanism when a torque reduction mechanism employ | adopts a 1st structure. It is a figure which shows the 2nd structure of a torque reduction mechanism. It is a figure which shows the relationship between the urging | biasing force of a valve spring and the reduction torque of a torque reduction mechanism when a torque reduction mechanism employ | adopts a 2nd structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 6 ... Intake port 7 ... Exhaust port 8 ... Intake valve 9 ... Exhaust valve 10 ... ..Intake side drive mechanism 11 ... Exhaust side drive mechanism 12 ... Fuel injection valve 13 ... Ignition plug 14 ... ECU
18 .... first motor 24 ...... second motor 60 ...... intake passage 70 ...... exhaust passage 80 ...... valve lifter 81 ...... first intake cam 82 ... Second intake cam 83 ··· First intake camshaft 84 ··· Second intake camshaft 88 ··· Intake valve spring 90 ··· Valve lifter 91 · · · Exhaust cam 92 ···・ Exhaust cam shaft 94... Exhaust side valve spring 100 ... Torque reduction mechanism 101 ... Torque reduction cam 102 ... Lifter 103 ... Torque reduction spring

Claims (5)

In a valve operating system for an internal combustion engine that rotates or swings a cam by a drive source independent of the internal combustion engine,
Control means for rotating a cam by the drive source when starting the internal combustion engine;
Discriminating means for discriminating the rotational position of the cam based on the required drive torque of the drive source when the control means is rotating the cam;
A valve operating system for an internal combustion engine, comprising: The drive source according to claim 1, wherein the drive source rotationally drives a cam of a plurality of cylinders.
The valve operating mechanism for a specific cylinder among the plurality of cylinders is configured such that the required drive torque of the drive source when the cam of the specific cylinder lifts the valve is the drive source when the cam of another cylinder lifts the valve. A valve operating system for an internal combustion engine, characterized in that it is configured to be different from the required drive torque.   3. The valve operating system for an internal combustion engine according to claim 2, wherein a spring constant of a valve spring provided in the valve operating mechanism of the specific cylinder is different from a spring constant of a valve spring provided in a valve operating mechanism of another cylinder. . In Claim 2, the valve operating mechanism of the plurality of cylinders includes a reduction mechanism that generates a reduction torque for reducing a reaction force generated when the cam lifts the valve,
2. A valve operating system for an internal combustion engine, wherein a reduction torque generated by a reduction mechanism of the specific cylinder is different from a reduction torque generated by a reduction mechanism of another cylinder.   5. The valve operating system for an internal combustion engine according to claim 1, wherein the drive source is an electric motor.

Images