JP2009264329A - Valve drive system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique holdscapable of quickly identifying a rotation position of a cam in a valve drive system of an internal combustion engine in which the cam rotated or rocked by a power engine independent of the internal combustion engine opens and closes the valve. <P>SOLUTION: In the valve drive system of an internal combustion engine having the cam rotated or rocked by the power engine independent of the internal combustion engine, the power engine rotates n times per one rotation of the cam. A cam position sensor is configured to output signals of different patterns according to rotation ranges in which the cam rotates during one rotation of the power engine. This makes it possible to quickly identify a rotation position of the cam. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a valve operating system for an internal combustion engine in which a cam rotated or swung by a prime mover independent of the internal combustion engine opens and closes the valve.

  In a valve operating system in which a cam of an internal combustion engine is rotated or oscillated by an electric motor (motor), the cam and the crankshaft are not physically connected. Therefore, it is necessary to detect the rotational position (phase) of the cam at the time of starting. .

On the other hand, a technique has been proposed in which the stop position of the cam is stored in a nonvolatile memory when the operation of the internal combustion engine is stopped (see, for example, Patent Document 1).
JP 2004-183612 A

  By the way, depending on the stop position of the cam, the cam position may change while the operation of the internal combustion engine is stopped. For example, since electric power is not supplied to the electric motor while the operation of the internal combustion engine is stopped, the electric motor cannot hold the cam position at a fixed position. Therefore, 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 using a cam position sensor is conceivable. However, the cam position sensor is a sensor that outputs a signal when a detected portion that rotates with the cam passes in the vicinity of the detecting portion. For this reason, when using the signal of the cam position sensor, it is necessary to rotate the cam until the detected portion passes near the detection portion. Therefore, the rotational position of the cam may not be specified quickly.

  The present invention has been made in view of various circumstances as described above, and an object thereof is a valve operating system for an internal combustion engine in which a valve rotated or rocked by a prime mover independent of the internal combustion engine opens and closes the valve. Therefore, the present invention is to provide a technique capable of specifying the rotational position of the cam as quickly as possible.

  In order to solve the above-described problems, the present invention provides a valve operating system for an internal combustion engine that includes a cam that is rotated or oscillated by a prime mover independent of the internal combustion engine, and the prime mover rotates n times per rotation of the cam. The rotational position of the cam is specified using a sensor (first sensor) that detects the rotational position of the cam and a sensor (second sensor) that outputs a signal of a different pattern for each range in which the cam rotates 1 / n. I did it.

  In a valve operating system in which a cam is rotated or swung by a prime mover independent of the internal combustion engine, the rotational position of the prime mover can be specified based on the output signal of the first sensor. At this time, if the rotational speed ratio of the prime mover to the cam (the number of times the prime mover rotates during one rotation of the cam) is 1, the rotational position of the cam can be uniquely identified based on the output signal of the first sensor. it can.

  By the way, when a speed reduction mechanism is interposed between the prime mover and the cam, the rotational speed ratio of the prime mover with respect to the cam does not become 1 (for example, the prime mover rotates a plurality of times while the cam makes one revolution). In such a case, the cam can take a plurality of rotational positions with respect to one rotational position of the prime mover.

For example, when the prime mover makes three revolutions (0 to 1080 degrees) per one revolution of the cam, the cam can take three rotational positions with respect to one rotational position of the prime mover. For this reason, it is necessary to specify how many rotations of the prime mover are in three rotations. That is, it is necessary to specify which of the following ranges (1) to (3) the rotational position of the prime mover belongs to.
(1) Range from 0 degrees to 360 degrees (2) Range from 360 degrees to 720 degrees (3) Range from 720 degrees to 1080 degrees

  In short, when the prime mover rotates n times (n is an integer greater than 1) while the cam rotates once, the cam can take n rotational positions with respect to one rotational position of the prime mover. Therefore, when the rotational speed ratio of the prime mover with respect to the cam is greater than 1, the rotational position of the cam (in other words, the correlation between the rotational position of the prime mover and the rotational position of the cam) is uniquely based only on the output signal of the first sensor. It becomes difficult to specify.

  On the other hand, by using a cam position sensor (second sensor) that outputs a signal when the detected part that rotates or swings in conjunction with the cam passes near the detection part, 1 of n rotational positions is obtained. A method of identifying one can be considered.

  In the method using the cam position sensor together, it is necessary to rotate the cam until the detected portion passes near the detecting portion. In particular, when the detected portion is in a state immediately after passing through the vicinity of the detecting portion, the cam must be rotated approximately 360 degrees, and there is a possibility that interference between the valve and the piston (valve stamp) may occur during that time. is there.

Accordingly, the present invention provides a valve operating system for an internal combustion engine in which a cam rotated or swung by a prime mover independent of the internal combustion engine opens and closes the valve.
A speed reduction mechanism for transmitting the rotational force of the prime mover to the cam so that the rotational speed of the cam is 1 / n of the rotational speed of the prime mover;
A first sensor that outputs a signal indicating a rotational position of the prime mover;
A second sensor that outputs a signal of a different pattern for each range in which the cam rotates 1 / n;
Identifying means for identifying a correlation between the rotational position of the prime mover and the rotational position of the cam based on output signals of the first sensor and the second sensor;
I was prepared to.

  In this invention, the second sensor outputs a signal having a different pattern for each range in which the cam rotates 1 / n. As a result, the specifying means can specify the number of rotations from the 1st to n-th rotations based on the output signal of the second sensor.

  For example, when the prime mover rotates three times while the cam rotates once (n = 3), the second sensor outputs a signal with a different pattern for each range in which the cam rotates 120 degrees. That is, when the rotational position of the cam belongs to the range of 0 to 120 degrees (when the rotational position of the prime mover belongs to the range of (1) above), it belongs to the range of 120 to 240 degrees. Case (when the rotational position of the prime mover belongs to the range of (2) above) and when it belongs to the range of 240 degrees to 360 degrees (when the rotational position of the prime mover belongs to the range of (3) above) ), The second sensor outputs signals of different patterns.

  Therefore, the specifying means can uniquely specify the rotational position of the cam and the rotational position of the prime mover by collating the output signal of the first sensor and the output signal of the second sensor.

  Since the above-described identification method can be performed with almost no rotation of the cam, the rotation position of the cam can be identified as quickly as possible, and the occurrence of a valve stamp can be avoided as much as possible. .

  The second sensor of the present invention, like a conventional cam position sensor, detects when a detected part provided on a rotating body that rotates or swings in conjunction with a cam and when the detected part passes a predetermined position. And a detection unit that outputs However, the detected parts are provided in each of the ranges in which the rotating body rotates 1 / n, and the shapes of the detected parts are different for each range.

  In this case, the detected portions are provided in n ranges divided for each 1 / n rotation range, and the shapes of the detected portions are different for each of the ranges described above. As a result, the detection unit can output a signal having a different pattern for each 1 / n rotation range.

  Note that the detection unit of the second sensor may be configured to be displaceable in the rotation direction of the detected portion (in other words, the rotation direction of the rotating body). According to such a configuration, even when the cam is in the rotation stop state, the second sensor moves the detection portion so that the rotation position (stop position) of the cam is in any of the n ranges. It is possible to detect whether it belongs.

  As a result, the specifying means can specify the rotation position (stop position) of the prime mover and the cam without rotating the cam when the cam is in the rotation stop state.

  By the way, there is a possibility that the valve stamp cannot be avoided if the crankshaft of the internal combustion engine is rotating even when the cam is stopped. Therefore, it is desirable that the specifying unit specifies the rotational positions of the prime mover and the cam by displacing the detection unit when the cam and the crankshaft are in a stopped state. Such a time can be exemplified before cranking of the internal combustion engine is started.

  The valve operating system for an internal combustion engine according to the present invention includes an acquisition unit that acquires the lift amount of the valve at the cam stop position specified by the specifying unit, and the lift amount acquired by the acquisition unit is a predetermined amount or more. Control means for controlling the prime mover to rotate the cam until the valve lift amount becomes less than a predetermined amount at a certain time may be further provided.

  The above-mentioned predetermined amount is the minimum lift amount that can generate the valve stamp when the piston is located at the top dead center, or the maximum lift amount that can avoid the valve stamp when the piston is located at the top dead center. .

  According to this configuration, no valve stamp is generated during cranking after the rotational positions of the prime mover and the cam are specified.

  According to the present invention, the rotational position of the cam can be specified as quickly as possible in the valve operating system of the internal combustion engine that is rotated or oscillated by the prime mover independent of the internal combustion engine.

  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 exhaust port 7 communicates with the exhaust passage 70. The exhaust passage 70 is connected to an exhaust purification device and a silencer (not shown).

  The intake air taken into 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 burned gas discharged to the exhaust port 7 is discharged to 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, an ignition switch 100, and a starter switch 200.

  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. In FIG. 2, # 1 to # 4 indicate 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 each 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 of 360 degrees CA 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 drive gear 19 fixed to the output shaft of the first motor 18. Hereinafter, the first driven gear 85 and the first drive gear 19 are collectively referred to as a first reduction mechanism. The reduction ratio of the first reduction mechanism is set so that the first motor 18 rotates three times per rotation of the first intake camshaft 83.

  According to such a configuration, the rotational torque of the first motor 18 is transmitted to the first intake camshaft 83 via the first reduction mechanism. Therefore, the first intake camshaft 83 rotates or swings in the circumferential direction when the first motor 18 continuously rotates in one direction or alternately rotates in the forward direction and the reverse direction.

  On the other hand, 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 meshes with the intermediate gear 87. The intermediate gear 87 meshes with the second drive 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 drive 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.

  According to such a configuration, the rotational torque of the second motor 21 is transmitted to the second intake camshaft 84 via the second reduction mechanism. Accordingly, the second intake camshaft 84 rotates or swings in the circumferential direction by continuously rotating the second motor 21 in one direction or alternately rotating in the forward direction and the reverse direction.

  The first motor 18 includes a first resolver 20 that detects the rotational position 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 rotational position of the output shaft, and a detection signal of the second resolver 23 is input to the ECU 14.

  A first cam position sensor 30 is attached to the first intake camshaft 83. A second cam position sensor 31 is attached to the second intake camshaft 84. Detection signals of the first cam position sensor 30 and the second cam position sensor 31 are input to the ECU 14.

  Next, the structure of the exhaust side drive mechanism 11 is demonstrated based on FIG. 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 each 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 all cylinders are fixed to one exhaust cam shaft 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 drive gear 25 attached to the output shaft of the third motor 24. Hereinafter, the third driven gear 93 and the third drive gear 25 are collectively referred to as a third reduction mechanism. The reduction ratio of the third reduction mechanism is equivalent to that of the first reduction mechanism and the second reduction mechanism described above.

According to such a configuration, the rotational torque of the third motor 24 is transmitted to the exhaust camshaft 92 via the third drive gear 25 and the third driven gear 93. Therefore, when the third motor 24 is continuously rotated in one direction or alternately rotated in the forward direction and the reverse direction, the exhaust camshaft 92 is rotated or oscillated in the circumferential direction.

  The third motor 24 includes a third resolver 26 that detects the rotational position of the output shaft, and a detection signal of the third resolver 26 is input to the ECU 14. A third cam position sensor 32 is attached to the exhaust camshaft 92. A detection signal of the third cam position sensor 32 is input to the ECU 14.

  In the intake side drive mechanism 10 and the exhaust side drive mechanism 11 described above, the first motor 18, the second motor 21, and the third motor 24 correspond to the prime mover according to the present invention. The first resolver 20, the second resolver 23, and the third resolver 26 correspond to the first sensor according to the present invention.

  In the valve train as described above, each camshaft and crankshaft 5 are not physically connected, so each cam (camshaft) rotates or swings at a timing synchronized with the rotation of the crankshaft 5. It is necessary to control each motor so that it operates dynamically.

  For example, the ECU 14 controls each motor such that each camshaft rotates once (360 degrees) while the crankshaft 5 rotates twice (720 degrees). In this case, the intake valve 8 and the exhaust valve 9 of the first 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). It opens and closes at a timing synchronized with the combustion cycle of the cylinder (# 4).

  By the way, 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 combustion cycle, the first intake cam is activated when each motor is started (for example, when the internal combustion engine 1 is started). It is necessary to detect the rotational positions of 81 (first intake camshaft 83), second intake cam 82 (second intake camshaft 84), and exhaust cam 91 (exhaust camshaft 92).

  As a method for detecting the rotational position of each camshaft, a method using a detection value of a resolver attached to each motor can be considered. At this time, if the rotation speed ratio of the motor to the camshaft (the number of rotations of the motor during one rotation of the camshaft) is 1, the rotation position of the motor is equal to the rotation position of the camshaft. Therefore, the rotational position of the camshaft can be uniquely specified based on the resolver signal.

  However, when a speed reduction mechanism is interposed between the motor and the camshaft, the rotational speed ratio of the motor to the camshaft is greater than 1. For this reason, the camshaft can take a plurality of rotational positions with respect to one rotational position of the motor.

  For example, as described in the description of FIGS. 2 and 3 described above, when the reduction ratio is 3 (when the rotational speed ratio of the motor with respect to the camshaft is 3), each camshaft rotates once (rotates 360 degrees). ), Each motor rotates three times (1080 degrees). In other words, each motor rotates once (360 degrees) while each camshaft rotates 1/3 (120 degrees).

  In this case, the cam (camshaft) can take three rotational positions with respect to one rotational position of the motor. For example, as shown in FIG. 4, when the output signal of the first resolver 20 indicates 270 degrees, the first intake cam 81 (first intake camshaft 83) has three types of 90 degrees, 210 degrees, and 330 degrees. The rotation position can be taken. In other words, when the output signal of the first resolver 20 indicates 270 degrees, the rotational position of the first motor 18 can take three rotational positions of 270 degrees, 630 degrees, and 990 degrees.

Therefore, when uniquely specifying the rotational position of each cam (camshaft), it is necessary to determine which of the following ranges (1) to (3) the rotational position of each motor belongs to. .
(1) Range of 0 to 360 degrees (2) Range of 360 to 720 degrees (3) Range of 720 to 1080 degrees

  However, it is difficult to make the above determination based only on the output signal of the resolver. For this reason, it is necessary to make the above determination using a cam position sensor attached to each camshaft. Examples of the cam position sensor used at that time include a sensor that outputs a signal when a detected portion that rotates or swings in conjunction with each camshaft passes a detection range (predetermined position) of the detection portion. it can.

  When using the cam position sensor as described above, it is necessary to rotate the camshaft until the detected portion passes the predetermined position when each motor is started, and the rotational position of the camshaft can be detected quickly. Can not. Further, if the camshaft is rotated when the piston 3 is located near the top dead center, the possibility of occurrence of interference between the valve and the piston 3 (valve stamp) increases.

  Therefore, the cam position sensors 30, 31, and 32 of the present embodiment can output different patterns of signals for each range in which the cam shafts 83, 84, and 92 rotate while the motors 18, 21, and 24 rotate once. It was adopted.

  Hereinafter, the configuration of the first cam position sensor 30 will be described. Note that the configurations of the second cam position sensor 31 and the third cam position sensor 32 are the same as those of the first cam position sensor 30, and thus the description thereof is omitted.

  As shown in FIG. 5, a disk-shaped rotor 300 is connected to one end of the first intake camshaft 83. In the rotor 300, a detected portion 301 is projected from a side surface opposite to the side surface to which the first intake camshaft 83 is connected.

  A detection unit 302 is disposed at a position facing the side surface of the rotor 300 on which the detection unit 301 is provided. The detection unit 302 is an electromagnetic pickup type detection element using, for example, a Hall element or an MRE (magnetoresistive element), and outputs an ON signal when the detected unit 301 passes in the immediate vicinity of the detection unit 302 unit. .

  The detected portion 301 is formed in a different shape every 120 degrees in the rotation direction of the first intake camshaft 83. For example, as shown in FIG. 6, the detected portion 301 is an arc-shaped protrusion (hereinafter referred to as “first detected portion”) 301 a extending over the entire range of 0 to 120 degrees in the rotation direction of the rotor 300. And a plurality of arc-shaped protrusions (hereinafter referred to as “second detected parts”) 301 b that are intermittently arranged in a range of 120 degrees to 240 degrees.

  In the example shown in FIG. 6, the second detected portion 301b has four arc-shaped protrusions having a width of 15 degrees in the rotation direction of the first intake camshaft 83, and these arc-shaped protrusions are spaced at 15-degree intervals. Has been placed.

  The first cam position sensor 30 configured in this manner outputs a signal having a pattern as shown in FIG. First, when the rotational position of the first intake cam 81 (first intake camshaft 83) is in the range of 0 degrees to 120 degrees, the first cam position sensor 30 continuously outputs an on signal.

  When the rotational position of the first intake cam 81 (first intake camshaft 83) is in the range of 120 degrees to 240 degrees, the first cam position sensor 30 intermittently outputs an on signal. Specifically, the first cam position sensor 30 outputs an ON signal for 15 degrees at intervals of 15 degrees.

  When the rotational position of the first intake cam 81 (first intake camshaft 83) is in the range of 240 degrees to 360 degrees, the first cam position sensor 30 continuously outputs an off signal.

  Therefore, when the first cam position sensor 30 continuously outputs an ON signal, the ECU 14 belongs to a range where the rotational position of the first intake cam 81 (first intake camshaft 83) is in the range of 0 degrees to 120 degrees. In addition, it can be determined that the rotational position of the first motor 18 belongs to a range of 0 degrees to 360 degrees.

  Further, when the first cam position sensor 30 intermittently outputs an ON signal, the ECU 14 belongs to a range where the rotational position of the first intake cam 81 (first intake camshaft 83) is in the range of 120 degrees to 240 degrees. In addition, it can be determined that the rotational position of the first motor 18 belongs to a range of 360 degrees to 720 degrees.

  Further, when the first cam position sensor 30 continuously outputs the off signal (in other words, when the state where the on signal is not output continues), the ECU 14 (the first intake camshaft 83). ) In the range of 240 degrees to 360 degrees, and the rotational position of the first motor 18 can be determined to belong to the range of 720 degrees to 1080 degrees.

  The determination as described above can be performed if the first intake cam 81 (first intake camshaft 83) rotates about 15 degrees. Therefore, the ECU 14 can quickly specify the rotational positions of the first intake cam 81 (first intake camshaft 83) and the first motor 18 when the first motor 18 is started including when the internal combustion engine 1 is started. it can. At this time, since the first intake cam 81 (first intake camshaft 83) has only to be rotated about 15 degrees, the possibility of occurrence of a valve stamp can be reduced as much as possible.

  In the example shown in FIGS. 6 and 7, the second detected parts 301b are provided at intervals of 15 degrees, but it is needless to say that the present invention is not limited to this. For example, when the rotational position of the first intake cam 81 (first intake camshaft 83) is specified by narrowing the width and interval of the second detected portion 301b within a range in which the detection accuracy of the detection unit 302 can be maintained. The amount of rotation of the first intake cam 81 (first intake camshaft 83) can be reduced.

  If the second cam position sensor 31 and the third cam position sensor 32 are also configured in the same manner as the first cam position sensor 30, the rotational position of the second intake cam 82 (second intake camshaft 84) and the second motor 21. The correlation with the rotational position and the correlation between the rotational position of the exhaust cam 91 (exhaust cam shaft 92) and the rotational position of the third motor 24 can be quickly identified.

  The 1st cam position sensor 30, the 2nd cam position sensor 31, and the 3rd cam position sensor 32 comprised in this way are corresponded to the 2nd sensor concerning this invention.

  The procedure for starting each motor will be described below with reference to FIG. FIG. 8 is a flowchart showing a control routine for starting each motor when the internal combustion engine 1 is started. This control routine is stored in advance in the ROM of the ECU 14.

In the control routine of FIG. 8, the ECU 14 first determines whether or not the ignition switch 100 has been switched from OFF to ON in S101. If a negative determination is made in S101, the ECU 14 ends the execution of this routine. On the other hand, when a positive determination is made in S101, the ECU 14 proceeds to S102.

  In S102, the ECU 14 rotates the first motor 18, the second motor 21, and the third motor 24 by a certain amount. For example, when the second detected portion 301b is configured as shown in FIGS. 6 and 7, the ECU 14 sets the first intake cam 81 (first intake cam shaft 83) and the second intake cam 82 ( The first motor 18, the second motor 21, and the third motor 24 are controlled so that the second intake camshaft 84) and the exhaust cam 91 (exhaust camshaft 92) rotate about 15 degrees.

  In S103, the ECU 14 reads output signals from the first resolver 20, the second resolver 23, and the third resolver 26.

  In S104, the ECU 14 reads output signals from the first cam position sensor 30, the second cam position sensor 31, and the third cam position sensor 32.

  In S105, the ECU 14 determines the rotational position (stop position) of each motor and each camshaft based on the output signal of each resolver read in S103 and the output signal of each cam position sensor read in S104. The rotation position (stop position) is specified.

  For example, when the output signal of the first resolver 20 indicates 270 degrees, the rotational position of the first motor 18 can take three rotational positions of 270 degrees, 630 degrees, and 990 degrees, and the first intake cam The rotational position of 81 (first intake camshaft 83) can take three rotational positions of 90 degrees, 210 degrees, and 330 degrees.

  On the other hand, if the first cam position sensor 30 continuously outputs the ON signal, the rotational position of the first intake cam 81 (first intake camshaft 83) belongs to the range of 0 degrees to 120 degrees. The rotational position of the first motor 18 belongs to the range of 0 degrees to 360 degrees. Therefore, the ECU 14 can specify that the rotational position of the first motor 18 is 270 degrees, and can specify that the rotational position of the first intake cam 81 (first intake camshaft 83) is 90 degrees.

  If the first cam position sensor 30 intermittently outputs an ON signal, the rotational position of the first intake cam 81 (first intake camshaft 83) belongs to the range of 120 degrees to 240 degrees, and the first The rotational position of one motor 18 belongs to the range of 360 degrees to 720 degrees. Therefore, the ECU 14 can specify that the rotational position of the first motor 18 is 630 degrees, and can specify that the rotational position of the first intake cam 81 (first intake camshaft 83) is 210 degrees.

  Further, if the first cam position sensor 30 continuously outputs the off signal, the rotational position of the first intake cam 81 (first intake camshaft 83) belongs to the range of 240 degrees to 360 degrees, and the first The rotational position of one motor 18 belongs to the range of 720 to 1080 degrees. Therefore, the ECU 14 can specify that the rotational position of the first motor 18 is 990 degrees, and can specify that the rotational position of the first intake cam 81 (first intake camshaft 83) is 330 degrees.

  The ECU 14 correlates the rotational position of the second motor 21 and the rotational position of the second intake cam 82 (second intake cam shaft 84), and the rotational position of the third motor 24 and the exhaust cam 91 (exhaust cam shaft 92). The correlation with the rotational position is also specified by the same procedure.

  Returning to FIG. 8, the ECU 14 determines whether or not cranking of the internal combustion engine 1 has been started in S106. As this determination method, a method of determining whether or not the starter switch 200 has been switched from OFF to ON, or whether or not the engine speed obtained from the output signal of the crank position sensor 15 is higher than “0” is exemplified. be able to.

  If a negative determination is made in S106, the ECU 14 once ends the execution of this routine. On the other hand, if a positive determination is made in S106, the ECU 14 proceeds to S107.

  In S107, the ECU 14 calculates the engine speed Ne from the output signal of the crank position sensor 15, and determines whether or not the engine speed Ne is equal to or higher than a predetermined speed Netrg. The above-mentioned predetermined rotation speed Netrg is a rotation speed at which a starter motor (not shown) can stably rotate the crankshaft 5 and is experimentally obtained in advance.

  When a negative determination is made in S107 (Ne <Netrg), the ECU 14 repeatedly executes the process of S107 until the cranking rotational speed Ne is stabilized at the predetermined rotational speed Netrg. On the other hand, if an affirmative determination is made in S107 (Ne ≧ Netrg), the ECU 14 proceeds to S108.

  In S108, the ECU 14 determines the combustion cycle of each cylinder 2. In other words, the ECU 14 determines the correlation between the rotational position (crank angle) of the crankshaft 5 and the combustion cycle of each cylinder 2.

  For example, the ECU 14 determines the crank angle at which the pistons 3 of the first cylinder (# 1) and the fourth cylinder (# 4) are located at the top dead center (TDC) (in other words, the second cylinder (# 2) and the third cylinder). (# 3) piston 3 is located at the bottom dead center (BDC)), the first cylinder (# 1) piston 3 is located at the compression top dead center and the fourth cylinder (# 4) The crank angle at which the piston 3 is located at the exhaust top dead center (in other words, the piston 3 of the second cylinder (# 2) is located at the expansion bottom dead center and the piston 3 of the third cylinder (# 3) is bottom dead at the intake side) Assign the crank angle at the point).

  The ECU 14 determines the crank angle at which the piston 3 of the first cylinder (# 1) and the fourth cylinder (# 4) is located at the top dead center (TDC) (in other words, the second cylinder (# 2) and the third cylinder). (# 3) piston 3 is located at the bottom dead center (BDC)), the first cylinder (# 1) piston 3 is located at the exhaust top dead center and the fourth cylinder (# 4) The crank angle at which the piston 3 is positioned at the compression top dead center (in other words, the piston 3 of the second cylinder (# 2) is positioned at the bottom dead center of intake and the piston 3 of the third cylinder (# 3) is expanded and dead) A crank angle located at a point) may be assigned.

  In S109, the ECU 14 activates each motor so that each cam (camshaft) rotates at a timing synchronized with the crank angle determined in S108.

  When each motor is started in this way, the intake and exhaust valves of each cylinder 2 open and close at a timing suitable for the combustion cycle assigned in S108.

  When the intake / exhaust valve of each cylinder 2 opens and closes at a timing suitable for the above-described combustion cycle, the ECU 14 proceeds to S110 and starts the operation of the fuel injection valve 12 and the spark plug 13 of each cylinder 2.

In this embodiment, the valve operating system (the intake side drive mechanism 10 and the exhaust side drive mechanism 11) and the internal combustion engine 1 are controlled by a common ECU 14, but the valve system and the internal combustion engine 1 are controlled by different ECUs. In this case, the ECU for the internal combustion engine cannot grasp the operation timing of the intake and exhaust valves (combustion cycle of each cylinder 2). For this reason, when the operation timing of the intake / exhaust valve is determined, the ECU for the valve operating system may notify the determination result to the ECU for the internal combustion engine.

  As described above, when the ECU 14 executes the control routine of FIG. 8, the specifying means according to the present invention is realized. As a result, the correlation between the rotational position of each motor and the rotational position of each camshaft can be quickly identified. Therefore, it is possible to shorten the starting period of the internal combustion engine 1 and to reduce the possibility of occurrence of a valve stamp.

  By the way, if the cranking of the internal combustion engine 1 is started before the ECU 14 finishes executing the processes of S102 to S105, a valve stamp may be generated. Therefore, if the starter switch 200 is switched from OFF to ON before completing the process of S105, the ECU 14 may prohibit the operation of the starter motor until the process of S105 is completed.

  Further, if the intake valve 8 and / or the exhaust valve 9 having a large lift amount are present when cranking of the internal combustion engine 1 is started, a valve stamp may be generated after the cranking is started.

  On the other hand, the ECU 14 determines the lift amounts of all the intake valves 8 and the exhaust valves 9 during a period from when the rotational position of each cam (camshaft) is specified until cranking of the internal combustion engine 1 is started. You may control each motor so that it may become less than fixed quantity.

  The predetermined amount described above is the minimum lift amount that can generate the valve stamp when the piston 3 is located at the top dead center, or the maximum lift amount that can avoid the valve stamp when the piston 3 is located at the top dead center. . It is assumed that such a predetermined amount is obtained experimentally in advance.

  Note that the rotational position (range of rotational position) of the motor or camshaft when the lift amount of each valve is less than a predetermined amount may be experimentally obtained in advance. In that case, the ECU 14 determines whether the rotational position of each motor or each camshaft belongs to the above-described range after executing the process of S105 described above. When there is a motor or camshaft at a rotational position that deviates from the above range, the ECU 14 may control the motor so that the rotational position of the motor or the camshaft falls within the above range.

<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 correlation between the rotational position of the motor and the rotational position of the cam (camshaft) is specified by slightly rotating each cam (camshaft) at the start of each motor. Stated.

  On the other hand, in this embodiment, an example will be described in which the correlation between the rotational position of the motor and the rotational position of the cam (camshaft) is specified without rotating the respective cams (camshafts) when the motors are started.

The cam position sensor of the present embodiment is configured such that the detection unit can be displaced in the rotation direction of the cam (camshaft). According to such a configuration, it is possible to specify a range to which the rotational position of the cam (camshaft) belongs without rotating the cam (camshaft).

  Hereinafter, the configuration of the first cam position sensor 30 in the present embodiment will be described with reference to FIGS. Note that the configurations of the second cam position sensor 31 and the third cam position sensor 32 are the same as those of the first cam position sensor 30, and thus the description thereof is omitted.

  The detection unit 302 of the first cam position sensor 30 is fixed to the rotating shaft 311 via the arm 310. The rotating shaft 311 is supported so as to be rotatable around the axis of the rotating shaft 311. It is assumed that the axis of the rotating shaft 311 is located on the same straight line as the axis of the first intake camshaft 83.

An actuator 312 for rotating (forward rotation) the rotation shaft 311 in the direction indicated by the arrow R in FIG. 9 is attached to the rotation shaft 311. The actuator 312 is electrically controlled by the ECU 14.
An example of the actuator 312 is an electric motor. The actuator 312 may be a solenoid that generates a force that presses the arm 310 in the direction of the arrow R, or may be an electromagnet that generates a magnetic force that attracts the arm 310 in the direction of the arrow R.

  A return spring 313 is connected to the detection unit 302 to urge the detection unit 302 in the reverse rotation direction (the direction opposite to the direction indicated by the arrow R). The base end of the return spring 313 is fixed to a cylinder head or the like (not shown).

  The return spring 313 serves to return the detection unit 302 that has been displaced in the forward rotation direction by the actuator 312 to a specified position (position shown in FIG. 9).

  Incidentally, the return spring 313 may vibrate during operation of the internal combustion engine 1 or the like. In such a case, since the position of the detection part 302 becomes unstable, the detection accuracy of the 1st cam position sensor 30 may fall.

  On the other hand, the first cam position sensor 30 includes a stopper 314 that comes into contact with the arm 310 when the detection unit 302 is at the specified position. The stopper 314 is disposed on the reverse side with respect to the arm 310.

  According to the first cam position sensor 30 configured as described above, when the actuator 312 is not operated, the return spring 313 presses the arm 310 against the stopper 314. For this reason, it is avoided that the position of the detection unit 302 becomes unstable due to vibration of the internal combustion engine 1 or the like. That is, the position of the detection unit 302 is held at the specified position.

  Further, when the actuator 312 generates a driving force, the arm 310 and the rotating shaft 311 rotate forward against the urging force of the return spring 313 as shown in FIG. The rotation angles of the arm 310 and the rotation shaft 311 at that time are determined based on the width and interval of the second detected part 301b described above. For example, as illustrated in FIG. 6 described above, when the width and interval of the second detected portion 301b are 15 degrees, the rotation angle of the arm 310 and the rotation shaft 311 is set to 15 degrees or slightly more than 15 degrees. Just do it.

When the arm 310 and the rotating shaft 311 are rotated forward in this way, the detection unit 302 outputs a signal having a pattern corresponding to the range to which the rotational position of the first intake cam 81 (first intake camshaft 83) belongs. Can do. Therefore, the first intake cam 81 (first intake camshaft 83)
The rotational position of the first intake cam 81 (first intake camshaft 83) and the rotational position of the first motor 18 can be specified without rotating the motor. As a result, the possibility of occurrence of a valve stamp can be further reduced.

  The procedure for starting each motor will be described below with reference to FIG. FIG. 12 is a flowchart showing a control routine for starting each motor when the internal combustion engine 1 is started. In FIG. 12, the same reference numerals are assigned to the processes equivalent to the control routine (see FIG. 8) of the first embodiment described above.

  In the control routine of FIG. 12, after executing S101, the ECU 14 executes S201 instead of S102. In S201, the ECU 14 operates the actuator to displace the detection unit of each cam position sensor in the rotation direction of each cam (camshaft).

  In S103, ECU14 reads the output signal of the resolver attached to each motor.

  In S104, ECU14 reads the pattern of the signal output, while the detection part of each cam position sensor displaced.

  In S105, the ECU 14 determines the rotation position (stop position) of each motor and each camshaft based on the output signal of each resolver read in S103 and the output signal of each cam position sensor read in S104. The rotation position (stop position) is specified.

  The processing after S106 is the same as the control routine of the first embodiment described above.

  According to the embodiment described above, it is possible to specify the correlation between the rotational position of each cam (camshaft) and the rotational position of each motor without rotating the cam (camshaft) when each motor is started. It becomes. As a result, it is possible to further reduce the possibility of occurrence of a valve stamp.

  In the first and second embodiments described above, the case where the correlation between the rotational position of each motor and the rotational position of each camshaft is specified when the internal combustion engine 1 is started is illustrated, but only when the internal combustion engine 1 is started. It is possible to specify the correlation between the rotational position of the motor and the rotational position of the camshaft by the same procedure if the stopped motor is started.

  In the first and second embodiments described above, the configuration in which the motor rotates three times while the cam (camshaft) makes one rotation is taken as an example, but it may be four or more. In short, it is only necessary that the shape of the detected portion is different for each range in which the cam (camshaft) rotates while the motor rotates once.

  Further, in the first and second embodiments described above, the example in which the detected portion 301 is provided on the side surface of the rotor 300 has been described, but it is needless to say that the present invention is not limited to this configuration. For example, the detected part may be provided on the outer peripheral surface of the rotor 300.

It is a figure which shows schematic structure of the valve operating system of an internal combustion engine. It is a figure which shows the structure of an intake side drive mechanism. It is a figure which shows the structure of an exhaust side drive mechanism. It is a figure which shows the relationship between the output signal of a 1st resolver, and the phase of a 1st intake cam. It is a 1st figure which shows the structure of the 1st cam position sensor in a 1st Example. It is a 2nd figure which shows the structure of the 1st cam position sensor in a 1st Example. It is a figure which shows the relationship between the output signal of a 1st resolver, the phase of a 1st intake cam, and the output signal of a 1st cam position sensor. 3 is a flowchart showing a control routine for starting each motor when the internal combustion engine is started in the first embodiment. It is a 1st figure which shows the structure of the 1st cam position sensor in a 2nd Example. It is a 2nd figure which shows the structure of the 1st cam position sensor in a 2nd Example. It is a figure which shows operation | movement of the 1st cam position sensor in a 2nd Example. It is a flowchart which shows the control routine for starting each motor at the time of starting of an internal combustion engine in a 2nd Example.

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 20 .... first resolver 21 ...... second motor 23 ...... second resolver 24 ...... third motor 26 ...... third resolver 30. ... 1st cam position sensor 31 ... 2nd cam position sensor 32 ... 3rd cam position sensor 60 ... Air intake passage 70 ... Air 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 300 ... Rotor 301 ... Detected part 301a ... First detected part 301b ... Second Detected part 3 02 ... Detector 310 ... Arm 311 ... Rotating shaft 312 ... Actuator 313 ... Return spring 314 ... Stopper

Claims (5)

In a valve operating system of an internal combustion engine in which a cam rotated or rocked by a prime mover independent of the internal combustion engine opens and closes the valve,
A speed reduction mechanism for transmitting the rotational force of the prime mover to the cam so that the rotational speed of the cam is 1 / n of the rotational speed of the prime mover;
A first sensor that outputs a signal indicating a rotational position of the prime mover;
A second sensor that outputs a signal of a different pattern for each range in which the cam rotates 1 / n;
Identifying means for identifying a correlation between the rotational position of the prime mover and the rotational position of the cam based on output signals of the first sensor and the second sensor;
A valve operating system for an internal combustion engine, comprising: 2. The detection unit according to claim 1, wherein the second sensor includes a detection unit provided on a rotating body that rotates or swings in conjunction with the cam, and a detection unit that outputs a signal when the detection unit passes a predetermined position. And comprising
The detected part is provided in each of the ranges where the rotating body rotates 1 / n, and the shape of the detected parts is different for each of the ranges. The detection unit of the second sensor according to claim 2, wherein the detection unit is configured to be displaceable in a rotation direction of the detection target unit.
The valve operating system for an internal combustion engine, wherein the specifying unit specifies a stop position of the cam by displacing the detection unit when the cam is in a rotation stop state.   4. The valve operating system for an internal combustion engine according to claim 3, wherein the specifying means specifies the stop position of the cam when the crankshaft of the internal combustion engine is in a rotation stop state. In Claim 4, the acquisition means which acquires the lift amount of the valve in the stop position of the cam specified by the specification means,
Control means for controlling the prime mover to rotate the cam until the lift amount of the valve becomes less than a predetermined amount when the lift amount acquired by the acquisition means is a predetermined amount or more;
Further comprising: a valve operating system for an internal combustion engine.

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