JP2009167902A - Valve system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of further correctly obtaining a cylinder determining signal in a valve system of an internal combustion engine in which a cam rotated or oscillated by a driving source independent of the internal combustion engine opens and closes a valve. <P>SOLUTION: The valve system includes: a sensor for outputting a signal if the cam is at a prescribed angle; a selection means for selecting a rotation behavior of the cam based on an operating state of the internal combustion engine; and a switching means for switching a method of processing a signal from the sensor based on results of selection by the selection means in detecting a rotational position of the cam (S101). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve operating system for an internal combustion engine in which a valve that is rotated or rocked by a drive source independent of the internal combustion engine opens and closes the valve.

  2. Description of the Related Art A valve operating system that rotates or swings a cam of an internal combustion engine with an electric motor (motor) is known (for example, see Patent Document 1). In this system, since the cam and the crankshaft are not physically connected, it is necessary to detect the rotational position (phase) of the cam at the time of starting or the like.

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 2).
WO2005 / 1119019 JP 2004-183612 A

  By the way, when the rotation position (phase) is detected by the projection attached to the camshaft passing the sensor, in the case of performing the swinging operation and the case of performing the rotation operation in one direction at a constant speed, The detection status of the sensors is different (an output signal from such a sensor is hereinafter also referred to as a “cylinder discrimination signal”). That is, when the cam shaft rotates once during the rotation of the cam shaft, the protrusion passes through the sensor once. However, during the swinging motion, the protrusion may pass through the sensor many times or not at all. As a result, if it becomes difficult to detect the rotational position of the cam, the timing of spark ignition or fuel injection may be wrong.

  The present invention has been made in view of the various circumstances as described above, and an object of the present invention is to provide a valve operating system for an internal combustion engine in which a cam rotated or swung by a drive source independent of the internal combustion engine opens and closes the valve. Is providing a technique capable of obtaining a cylinder discrimination signal more accurately.

In order to achieve the above object, a valve operating system for an internal combustion engine according to the present invention employs the following means. That is, the valve operating system for an internal combustion engine according to the present invention is:
In a valve operating system for an internal combustion engine in which a valve rotated or swung by a drive source independent of the internal combustion engine opens and closes the valve,
A sensor that outputs a signal when the cam is at a predetermined angle;
Selection means for selecting a rotational operation mode of the cam based on an operating state of the internal combustion engine;
Switching means for switching a processing method of a signal from the sensor based on a selection result by the selection means when detecting the rotational position of the cam;
It is characterized by providing.

  In a valve operating system in which a cam is rotated or oscillated by a drive source independent of the internal combustion engine, the rotational direction and rotational speed of the cam can be changed. That is, the cam can be swung by alternately changing the rotation direction of the cam between one and the other. Thereby, the lift amount of the cam can be changed. Further, the cam operating angle can be changed by changing the cam rotation speed relative to the crankshaft rotation speed. When the cam is rotating in one direction at a constant speed, the rotational position of the cam can be specified based on the output signal of the sensor.

  By the way, the internal combustion engine may be controlled according to the rotational position of the cam. For example, spark ignition or fuel injection may be performed in accordance with the output signal of the sensor. In other words, depending on the rotational position of the cam, which cylinder is ignited or which cylinder is subjected to fuel injection may be determined.

  However, when the cam is swinging, there is no output from the sensor or it is output a plurality of times. Further, when the rotational speed of the cam is changed, the relationship between the output timing from the sensor and the crank angle may change. As a result, it may be difficult to control the internal combustion engine.

  On the other hand, in the present invention, the handling of the sensor output is changed based on the rotational operation mode of the cam. Here, the rotational operation mode of the cam includes, for example, a case where the cam is rotated in one direction at a constant speed, a case where the cam is swinging, or a case where the rotational speed of the cam is variable (hereinafter, The operation of the cam with the rotation speed being variable is also referred to as variable speed operation.). The selection means selects one of the rotational operation modes of the cam based on the operating state of the internal combustion engine.

  Then, by switching the signal processing method from the sensor in accordance with the cam rotation operation mode, processing according to the cam rotation operation mode at that time can be performed. Thereby, even if the relationship between the output timing from the sensor and the crank angle changes, the cam rotation angle can be appropriately obtained.

  In the present invention, except when the cam is rotating at a constant speed in one direction, if the cam is rotating at a constant speed in one direction, the cam is at a predetermined angle. A signal may be output from the sensor.

  That is, when the cam is rotating in one direction at a constant speed, the rotational position of the cam can be obtained even if the output signal of the sensor is used as it is. On the other hand, when the cam is oscillating or when the rotation speed is changing, if the cam is rotating at a constant speed, there is an output from the sensor at the timing when the signal is output from the sensor. It is supposed to be. In this case, a signal from the sensor may be generated in a pseudo manner. In other words, during the cam swinging operation or variable speed operation, if the swinging operation or speed change is not performed, it is assumed that the output is from the sensor at a time when the cam is at a predetermined angle.

  In this way, the cylinder discrimination signal can be obtained even when the rotational position of the cam cannot be obtained based on the sensor output. Even when the cam is rotating in one direction at a constant speed, the signal output from the sensor may be used as it is without being used as it is.

  According to the present invention, a cylinder discrimination signal can be obtained more accurately in a valve operating system of an internal combustion engine that is rotated or oscillated by a drive source 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. 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 intake air (air mixture) introduced into the cylinder 2 are burned by the spark generated by the spark plug 13. 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 and a cam controller 141. The ECU 14 and the cam controller 141 are electronic control units each composed of 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 and a water temperature sensor 16.

  The ECU 14 electrically controls the fuel injection valve 12 and the spark plug 13 based on the measurement values of the various sensors described above. The cam controller 141 electrically controls the intake side drive mechanism 10 and the exhaust side drive mechanism 11 based on the measured values of various sensors. In this embodiment, the ECU 14 and the cam controller 141 are separate, but may be integrated.

  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 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 of 360 ° 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 gear mechanism. The reduction ratio of the first gear mechanism is set so that the first motor 18 makes two rotations per one rotation of the first intake camshaft 83.

  In this case, the rotational torque of the first motor 18 is transmitted to the first intake camshaft 83 via the first gear mechanism. Therefore, the first motor 18 can rotate or swing the first intake camshaft 83 in the circumferential direction via the first gear 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 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 gear mechanism. The reduction ratio by the second gear mechanism is equivalent to that of the first gear 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 gear mechanism. Therefore, the second motor 21 can rotate or swing the second intake camshaft 84 in the circumferential direction via the second gear mechanism.

  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 cam controller 141. 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 cam controller 141.

  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.

  A first detected portion 33 is installed on the first intake camshaft 83. The first detected portion 33 rotates or swings in conjunction with the first intake camshaft 83. Further, the detection portion (predetermined position) of the first cam position sensor 30 is not linked to the first intake camshaft 83 and is fixed in position. A signal is output from the first cam position sensor 30 when the first detected portion 33 passes the detection portion (predetermined position) of the first cam position sensor 30.

  On the other hand, the second detected portion 34 is installed on the second intake camshaft 84. The second detected portion 34 rotates or swings in conjunction with the second intake camshaft 84. Further, the detection part (predetermined position) of the second cam position sensor 31 is not interlocked with the second intake camshaft 84 and is fixed in position. When the second detected portion 34 passes the detection portion (predetermined position) of the second cam position sensor 31, a signal is output from the second cam position sensor 31. The detection signals of the first cam position sensor 30 and the second cam position sensor 31 are input to the cam controller 141.

Note that the attachment positions of the first cam position sensor 30 and the first detected portion 33 may be reversed. That is, the first cam position sensor 30 is connected to the first intake camshaft 83.
The position of the first detected part 33 may be fixed by rotating or swinging in conjunction with Similarly, the attachment positions of the second cam position sensor 31 and the second detected portion 34 may be reversed.

  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 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 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 gear mechanism. The reduction ratio of the third gear mechanism is equivalent to that of the first gear mechanism and the second gear mechanism described above.

  In this case, 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, the third motor 24 can rotate or swing the exhaust camshaft 92 in the circumferential direction via the third gear mechanism.

  The third motor 24 includes a third resolver 26 that detects the rotational position of the output shaft, and a detection signal from the third resolver 26 is input to the cam controller 141. A third cam position sensor 32 is attached to the exhaust camshaft 92.

  Further, the exhausted camshaft 92 is provided with a third detected portion 35. The third detected portion 35 rotates or swings in conjunction with the exhaust camshaft 92. The detection part (predetermined position) of the third cam position sensor 32 is not linked to the exhaust camshaft 92 and is fixed in position. A signal is output from the third cam position sensor 32 when the third detected portion 35 passes the detection portion (predetermined position) of the third cam position sensor 32. The detection signal of the third cam position sensor 32 is input to the cam controller 141. Note that the attachment positions of the third cam position sensor 32 and the third detected portion 35 may be reversed.

  In the present embodiment, the first motor 18, the second motor 21, and the third motor 24 correspond to the drive source in the present invention. In the present embodiment, the first cam position sensor 30, the second cam position sensor 31, or the third cam position sensor 32 corresponds to the sensor in the present invention.

  In the valve train configured as described above, the cam controller 141 rotates or swings the first motor 18, the second motor 21, and the third motor 24 at a timing synchronized with the rotation of the crankshaft 5. The timing at which 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 (# 4)). ) At a timing synchronized with the combustion cycle of). Here, it is determined by the ECU 14 or the cam controller 141 whether each motor is rotated in one direction at a constant speed, or the swinging operation or the variable speed operation is performed. In this case, it is determined according to the operating state of the internal combustion engine 1 (for example, engine speed or engine load, cooling water temperature, etc.). That is, in this embodiment, the ECU 14 or the cam controller 141 corresponds to the selection means in the present invention.

Incidentally, the cam controller 141 and the ECU 14 are connected by electrical wiring, and a cylinder discrimination signal is transmitted from the cam controller 141 to the ECU 14, and a crank signal is transmitted from the ECU 14 to the cam controller 141. The crank signal is a signal obtained by the crank position sensor 15. The cylinder discrimination signal is a signal obtained by the first cam position sensor 30, the second cam position sensor 31, and the third cam position sensor 32. In accordance with the cylinder discrimination signal, the ECU 14 determines which cylinder is to be injected with fuel or which cylinder is to be ignited. However, during camshaft swinging or variable speed operation, the relationship between the output signal from the cam position sensor and the combustion cycle changes, so the output signal from the cam position sensor is used as it is and the fuel injection timing And it becomes difficult to control the spark ignition timing.

  Therefore, in the valve operating system for the internal combustion engine in this embodiment, a cylinder discrimination signal is output if the camshaft is rotating at a constant speed during the camshaft swinging operation and variable speed operation. At this time, a cylinder discrimination signal is generated and output. That is, the output method of the cylinder discrimination signal is switched between the camshaft rotating operation and the swinging operation or the variable speed operation. It is assumed that the relationship between the rotational position of the camshaft and the rotational position of the motor that drives the camshaft has been obtained in advance.

  Hereinafter, the procedure for outputting the cylinder discrimination signal will be described with reference to FIG. FIG. 4 is a flowchart showing a control routine for switching the processing method of the cylinder discrimination signal. This control routine is stored in advance in the ROM of the cam controller 141, and is repeatedly executed at predetermined time intervals. In the flow shown in FIG. 4, the first intake camshaft 83 will be described, but the same applies to the second intake camshaft 84 and the exhaust camshaft 92.

  In the control routine of FIG. 4, the cam controller 141 first determines in S101 whether or not the first intake camshaft 83 is operating at a constant rotational speed. That is, it is determined whether or not the vehicle is rotating in the positive direction at a constant speed. Hereinafter, the fact that the camshaft rotates in the positive direction at a constant speed is also referred to as “constant rotation operation”. If a positive determination is made in S101, the process proceeds to S104. On the other hand, if a negative determination is made, the process proceeds to S102. In this embodiment, the cam controller 141 that executes S101 corresponds to the switching means in the present invention.

  In S102, a cylinder discrimination signal corresponding to the constant rotation operation of the first intake camshaft 83 is generated. This will be described later. In S103, the cylinder discrimination signal generated in S102 is output to the ECU 14.

  In S104, the cam controller 141 outputs the signal obtained by the first cam position sensor 30 as it is to the ECU 14 as a cylinder discrimination signal. Note that a signal after performing processing such as correcting the signal obtained by the first cam position sensor 30 may be used as the cylinder discrimination signal.

  Next, generation of the cylinder discrimination signal corresponding to the constant rotation operation in S102 will be described.

  First, the cam controller 141 calculates the current crank angle based on the crank signal and the front / back determination of the first intake camshaft 83. The crank signal is a value obtained from the ECU 14. In this embodiment, the compression top dead center of the first cylinder (# 1) is used as a reference, and the crank angle at this time is 0 degree. That is, when the crank angle is 0 degree, the piston 3 of the fourth cylinder (# 4) is located at the exhaust top dead center.

The front / back determination of the camshaft will be described. Here, when the rotation speed ratio of the motor to the camshaft is 2, the motor rotates twice (720 degrees) while the camshaft rotates once (360 degrees). Therefore, the rotational position of the motor belongs to a range of 0 degrees to 360 degrees (the rotational position of the camshaft is a range of 0 degrees to 180 degrees), or the range of 360 degrees to 720 degrees (the rotational position of the camshaft is 180 degrees). It is difficult to determine whether it belongs to the range of ~ 360 degrees based only on the output signal of the resolver.

  On the other hand, if a cam position sensor is attached to each camshaft, a signal (ON signal) can be output when a detected part that rotates or swings in conjunction with each camshaft passes a predetermined position.

  Thus, the rotational position of the motor belongs to the range of 0 to 360 degrees (the rotational position of the camshaft is in the range of 0 to 180 degrees), or the range of 360 to 720 degrees (the rotational position of the camshaft is In this embodiment, the determination of whether or not it belongs to the range of 180 degrees to 360 degrees is referred to as camshaft front / back determination.

  When the cam controller 141 controls the camshaft while the internal combustion engine 1 is operating, the cam controller 14 always knows the rotational position of the camshaft, so there is no need to make a front / back determination.

  Next, the cam controller 141 calculates a reference crank angle based on the phase advance angle request value. The phase advance angle required value is a value that represents how much the position where the lift amount of the cam is maximum changes with respect to the crank angle. A method of calculating the phase advance request value will be described later.

  FIG. 5 is a diagram showing the relationship among the crank angle, the reference crank angle, and the lift amount of the cam on the same time axis. The reference crank angle is determined as a value that changes with a phase advance request value delayed from the current crank angle. This reference crank angle is equal to the target angle of the motor when the cam is rotating. During a constant rotation of the camshaft, the cam lift amount is maximized when the reference crank angle is zero. Further, during cam swinging operation and variable speed operation, a virtual crank angle is calculated based on the reference crank angle and a plurality of control maps, and the virtual crank angle is set as the target angle of the motor.

  Here, FIG. 6 shows the timing when the intake valve and the exhaust valve of the fourth cylinder (# 4) and the third cylinder (# 3) are open (hatched portion), the first intake camshaft 83, the second intake camshaft. 84 and the reference crank angle of each of the exhaust camshafts 92. The horizontal axis is the actual crank angle. In the reference crank angle, the solid line indicates the case of the first intake camshaft 83, the two-dot chain line indicates the second intake camshaft 84, and the one-dot chain line indicates the case of the exhaust camshaft 92.

  The first intake camshaft 83 will be described based on FIG. In this case, when the reference crank angle is 0 degree, the lift amount of the intake valve 8 of the fourth cylinder (# 4) is maximized (that is, the lift amount of the first intake cam 81 is maximized). A reference crank angle is set.

  A cylinder discrimination signal is output based on this reference crank angle. That is, the cylinder discrimination signal is output when the reference crank angle becomes a predetermined angle. The predetermined angle is an angle at which a signal is output from the first cam position sensor 30 when the first intake camshaft 83 is rotating in the positive direction at a constant speed.

Here, when the first cylinder (# 1) is at the compression top dead center (crank angle 0 degree), the fourth cylinder (# 4
) Becomes the exhaust top dead center, and the intake stroke of the fourth cylinder (# 4) is started. The phase advance request value is obtained as follows.

If the intake valve 8 of the fourth cylinder (# 4) starts to open at the exhaust top dead center, the lift amount of the first intake cam 81 is maximized at a half of the operating angle VANGLIN of the first intake cam 81. The angle VLMAXCRKIN ′ required from when the intake valve 8 starts to open until the lift amount of the first intake cam 81 becomes maximum is:
VLMAXCRKIN '= VANGLIN / 2
It becomes. The working angle VANGLIN of the first intake cam 81 is determined according to the operating state of the internal combustion engine 1 at that time. In this embodiment, VLMAXCRKIN ′ = 105 (CA).

Next, when the valve timing is retarded most, an angle VLMAXCRKIN1 required from when the intake valve 8 starts to open until the lift amount of the first intake cam 81 becomes maximum is obtained. Note that the retard amount VOPTIN when the valve timing is most retarded is set in advance based on the specifications of the internal combustion engine 1 and the like. Assuming that the angle of the direction in which the intake valve 8 starts to open is delayed,
VLMAXCRKIN1 = VLMAXCRKIN '+ VOPNTIN
Can get a relationship. This angle VLMAXCRKIN1 is the phase advance angle required value. In this embodiment, VOPTINN = 15 (CA), so VLMAXCRKIN1 = 120 (CA).

The position where the lift amount of the first intake cam 81 of the fourth cylinder is maximized (that is, the position where the reference crank angle is 0 degree) is the lift of the first intake cam 81 with respect to the actual crank angle GNERK. The reference crank angle GNECRNK_IN1 of the first intake camshaft 83 is set to be delayed by the angle VLMAXCRKIN1 required for the amount to become the maximum.
GNEKRNK_IN1 = GNECRK-VLMAXCRKIN1
It becomes.

When the cam is advanced by the variable valve mechanism, the advance angle IN1VT is added. In this case, the phase advance angle request value is VLMAXCRKIN1-IN1VT, and the reference crank angle GNECRNK_IN1 of the first intake camshaft 83 is
GNECRNK_IN1 = necrk−VLMAXCRKIN1 + IN1VT
It becomes.

Next, the second intake camshaft 84 will be described. First, when the valve timing of the third cylinder (# 3) with respect to the crank angle is most retarded, an angle VLMAXCRKIN2 required until the lift amount of the second intake cam 82 is maximized after the intake valve 8 starts to open is obtained. . The maximum lift position of the third cylinder (# 3) is 180 degrees before the maximum lift position of the fourth cylinder (# 4).
VLMAXCRKIN2 = VLMAXCRKIN1-180
The relationship holds. In this embodiment, VLMAXCRKIN2 = −60 (CA).

Similarly to the case of the fourth cylinder (# 4), the reference crank angle GNECRNK_IN2 of the second intake camshaft 84 can be obtained by the following equation.
GNECRNK_IN2 = GNECRK-VLMAXCRKIN2 + IN2VT

  In this case, the phase advance angle request value is VLMAXCRKIN2-IN2VT.

  Next, the exhaust camshaft 92 will be described. In this case, when the reference crank angle is 0 degree, the reference crank is set so that the lift amount of the exhaust valve 9 of the fourth cylinder (# 4) is maximized (that is, the lift amount of the exhaust cam 91 is maximized). An angle is set.

  When the exhaust valve is completely closed at the exhaust top dead center, the lift amount of the exhaust cam 91 is maximized at half the working angle VANGLEX of the exhaust cam 91. Therefore, the exhaust valve starts from when the lift amount of the exhaust cam 91 is maximum. The angle VLMAXCRKEX ′ required for 9 to completely close is

VLMAXCRKEX '= VANGLEX / 2
It becomes. The cam operating angle VANGLEX is determined according to the operating state of the internal combustion engine 1 at that time.

Next, the angle VLMAXCRKEX required until the exhaust valve 9 is completely closed from the position where the lift amount of the exhaust cam 91 is maximum when the valve timing is most retarded is obtained. The retard amount VCLSTEX when the valve timing is most retarded is set in advance based on the specifications of the internal combustion engine 1 and the like. If the angle in the direction in which the exhaust valve 9 is delayed to close is subtracted and the unit is aligned with the intake side,
VLMAXCRKEX =-(VLMAXCRKEX'-VCLSTEX)
The following equation can be obtained. This angle VLMAXCRKEX becomes the phase advance angle required value. In this embodiment, VLMAXCRKEX = 106 (CA).

The position where the lift amount of the exhaust cam 91 of the fourth cylinder is maximized (that is, the position where the reference crank angle is 0 degree) is the maximum lift amount of the exhaust cam 91 with respect to the actual crank angle GNERK. The reference crank angle GNECRNK_EX of the exhaust camshaft 92 is delayed by the angle VLMAXCRKEX required to become
GNECRNK_EX = GNECRK-VLMAXCRKEX
It becomes.

If the exhaust cam 91 is advanced by the variable valve mechanism, the amount of advance EXVT is added (however, it is negative because the closing is delayed). In this case, the phase advance angle request value is VLMAXCRKEX + EXVT, and the reference crank angle GNECRNK_EX of the exhaust camshaft 92 is
GNECRNK_EX = GNECRK-VLMAXCRKEX-EXVT
It becomes.

  In this way, the reference crank angle can be calculated for each of the first intake camshaft 83, the second intake camshaft 84, and the exhaust camshaft 92.

  When the camshaft rotates in one direction at a constant speed, signals obtained by the first cam position sensor 30, the second cam position sensor 31, and the third cam position sensor 32 are used as cylinder discrimination signals. The data is output to the ECU 14 as it is.

  On the other hand, when the camshaft swings, that is, when forward rotation and reverse rotation are performed, a cylinder discrimination signal is generated by the cam controller 141 and output to the ECU 14 when the reference crank angle reaches a predetermined angle. To do. This predetermined angle is output from the first cam position sensor 30, the second cam position sensor 31, and the third cam position sensor 32 when the camshaft is rotating in a constant direction at a constant speed. It is an angle.

  Also in the case of variable speed operation of the camshaft, a cylinder discrimination signal is generated by the cam controller 141 and output to the ECU 14 when the reference crank angle reaches a predetermined angle.

  Thus, the cylinder discrimination signal can be accurately obtained by switching the processing method of the signal from the cam position sensor based on the rotational operation mode of the cam (camshaft). In this embodiment, the processing method of the output signal from the cam position sensor is switched based on the three modes of constant rotation operation, swing operation, or variable speed operation, but the same applies to other operation modes. Can be applied to.

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 flowchart which shows the control routine for switching the processing method of a cylinder discrimination | determination signal. It is the figure which showed on the same time axis the relationship between a crank angle, a reference | standard crank angle, and the lift amount of a cam. It is the figure which showed transition of the time (hatching part) when the intake valve and exhaust valve of the 4th cylinder (# 4) and the 3rd cylinder (# 3) are opened, and the reference crank angle of each camshaft. .

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 33 ... 1st detected part 34 ... 2nd detected part 35 ... ... 3rd detected part 60 ... Air intake passage 70 ... Air exhaust passage 80 ... Valve lifter 81 ... 1st air intake cam 82 ... 2nd air intake cam 83 ...・ First intake camshaft 84 ・ ・ ・ ・ Second intake camshaft 88 ・ ・ ・ ・ Inlet valve spring 90 ・ ・ ・ ・ Valve lifter 91 ・ ・ ・ ・ Exhaust cam 92 ・ ・ ・ ・ Exhaust camshaft 94・ Exhaust side valve spring 141 Controller

Claims (2)

In a valve operating system for an internal combustion engine in which a valve rotated or swung by a drive source independent of the internal combustion engine opens and closes the valve,
A sensor that outputs a signal when the cam is at a predetermined angle;
Selection means for selecting a rotational operation mode of the cam based on an operating state of the internal combustion engine;
Switching means for switching a processing method of a signal from the sensor based on a selection result by the selection means when detecting the rotational position of the cam;
A valve operating system for an internal combustion engine, comprising:   Except when the cam is rotating at a constant speed in one direction, if the cam is rotating at a constant speed in one direction, a signal is output from the sensor when the cam is at a predetermined angle. The valve operating system for an internal combustion engine according to claim 1, wherein:

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