JP2010065597A - Valve system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for determining a rotational position of a cam when a cam position sensor causes failure, in a valve system of an internal combustion engine for driving a valve for opening-closing by the cam rotated or rocked by an electric motor. <P>SOLUTION: The valve system of the internal combustion engine for rotating the electric motors in a plurality per one rotation of the cam for solving the problem, specifies a plurality of rotational positions taken by the cam from the rotational position of the electric motors, and operates the electric motors by temporarily determining one rotational position among these positions as an actual rotational position of the cam, and discriminates correctness of a temporary determining result based on the suction air volume of the internal combustion engine in that case. This valve system of the internal combustion engine also specifies the actual rotational position of the cam based on the correctness of the temporary determining result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a valve operating system for an internal combustion engine in which a valve rotated or swung by a prime mover independent of the internal combustion engine drives a valve, and more particularly to a technique for specifying the rotational position of the cam of each cylinder.

  Conventionally, a valve operating system has been proposed in which a valve is opened and closed by rotating or swinging a cam by a prime mover (for example, an electric motor) independent of an internal combustion engine. In such a valve operating system, since the cam and the crankshaft are not physically connected, it is necessary to detect the rotation angle (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 Japanese Patent Laid-Open No. 5-52172

  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, 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 of specifying the rotational position of the cam using a sensor that detects the rotational position of the prime mover can be considered. However, when the ratio between the rotational speed of the prime mover and the rotational speed of the cam does not become “1”, especially when the prime mover rotates a plurality of times per one rotation of the cam, a plurality of cams are associated with one rotational position of the prime mover. The rotation position can be taken. Therefore, it is difficult to uniquely identify the rotational position of the cam using only the sensor that detects the rotational position of the prime mover.

  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 rotationally driven by different prime movers, a plurality of cam position sensors are required. For this reason, while the number of parts of a valve operating system increases, manufacturing cost may increase. Further, when the cam position sensor breaks down, it becomes impossible to acquire the rotational position of the cam, and it may be difficult to retreat the vehicle on which the internal combustion engine is mounted.

  The present invention has been made in view of the above-described various circumstances, and an object of the present invention is to provide 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. In the above, there is provided a technique that makes it possible to determine the rotational position of the cam when the cam position sensor fails.

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 driven by a prime mover independent of the internal combustion engine opens and closes the valve. The prime mover is operated assuming that one of the rotational positions is the rotational position of the cam, and the actual rotational position of the cam (hereinafter referred to as “actual rotational position”) according to the intake air amount of the internal combustion engine at that time. ")".

Specifically, the present invention relates to a valve operating system for an internal combustion engine in which a cam driven by a prime mover independent of the internal combustion engine opens and closes the valve.
A speed reduction mechanism for decelerating the rotation of the prime mover and transmitting it to the cam;
Detecting means for detecting a rotational position of the prime mover;
Specifying means for specifying a plurality of rotational positions that the cam can take with respect to the detection value of the detecting means;
Temporary determination means for operating the prime mover on the assumption that one of the plurality of rotation positions specified by the specifying means is the rotation position of the cam;
Obtaining means for obtaining a physical quantity correlated with an intake air quantity of the internal combustion engine when the prime mover is operated by the temporary judging means;
A determination unit that determines whether or not the temporary determination result of the temporary determination unit is correct based on the physical quantity acquired by the acquisition unit, and that determines an actual rotational position of the cam according to the determination result;
I was prepared to.

  The physical quantity correlated with the intake air quantity of the internal combustion engine can be exemplified by intake air quantity, intake passage pressure (intake pipe pressure), and the like.

  In a valve operating system in which a cam is rotated or oscillated by a prime mover independent of an internal combustion engine, the rotational position of the prime mover can be specified by a sensor that detects the rotational position of the prime mover. 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 revolution of the cam) is 1, the actual rotational position of the cam can be uniquely specified based on the measured value of the sensor. it can.

  However, 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 rotational speed ratio of the prime mover with respect to the cam is 2, the cam can take two rotational positions with respect to one rotational position of the prime mover. Therefore, when the rotational speed ratio is 2, the rotational position of the prime mover belongs to the range of 0 to 360 degrees (the rotational position of the cam is in the range of 0 to 180 degrees), or the rotational position of the prime mover is It is necessary to identify whether it belongs to the range of 360 degrees to 720 degrees (cam rotation position is in the range of 180 degrees to 360 degrees).

  On the other hand, the valve operating system for an internal combustion engine according to the present invention temporarily determines that one of the plurality of rotational positions that the cam can take with respect to the rotational position of the prime mover is the rotational position of the cam. Subsequently, the valve operating system for the internal combustion engine of the present invention operates the prime mover according to the result of the temporary determination. At this time, the intake air amount of the internal combustion engine differs between the case where the temporary determination result is correct and the case where the temporary determination result is incorrect. Therefore, the rotational position of the cam can be specified based on the intake air amount of the internal combustion engine.

  The operating angle of the intake valve and the exhaust valve when the temporary determination means operates the prime mover is incorrect when the temporary determination result is correct (when the temporary determination result matches the actual rotational position) and when the temporary determination result is incorrect. In the case (when the temporary determination result and the actual rotational position do not match), it is preferable that the valve overlap amount is determined to be different.

For example, in a 4-stroke cycle internal combustion engine, when the prime mover rotates twice while the cam rotates once, the intake valve operating angle is set to the length of one stroke (intake stroke) and the exhaust valve operates. The angle may be set to a length of two strokes (expansion stroke and exhaust stroke).

  If the rotational position of the exhaust cam can be specified and the temporary determination result regarding the rotational position of the intake cam is incorrect, the intake valve opens in the expansion stroke. In that case, both the intake valve and the exhaust valve are opened in the expansion stroke. For this reason, gas flows into the cylinder from both the intake system and the exhaust system. Therefore, the intake air amount of the internal combustion engine is reduced.

  If the rotational position of the exhaust cam can be specified and the provisional determination result regarding the rotational position of the intake cam is correct, the intake valve opens in the intake stroke. In that case, only the intake valve opens in the intake stroke. For this reason, gas flows into the cylinder only from the intake system. Therefore, the intake air amount of the internal combustion engine increases.

  If the rotational position of the intake cam can be specified and the temporary determination result regarding the rotational position of the exhaust cam is incorrect, the exhaust valve opens in the intake stroke and the compression stroke. In that case, both the intake valve and the exhaust valve are opened in the intake stroke. For this reason, gas flows into the cylinder from both the intake system and the exhaust system. Therefore, the intake air amount of the internal combustion engine is reduced.

  If the rotational position of the intake cam can be specified and the temporary determination result regarding the rotational position of the exhaust cam is correct, the exhaust valve opens in the expansion stroke and the exhaust stroke. In that case, only the intake valve opens in the intake stroke. For this reason, gas flows into the cylinder only from the intake system. Therefore, the intake air amount of the internal combustion engine increases.

  If the prime mover rotates twice while the cam rotates once, the intake valve operating angle is set to the length of two strokes (intake stroke and compression stroke) and the exhaust valve operating angle is set to one stroke. You may set to the length of (exhaust stroke).

  In short, when the working angle of the intake valve or exhaust valve is set to a length corresponding to two strokes, the working angle is set so that the lift amount of the intake valve or exhaust valve does not increase when the piston is located at the top dead center. It is preferable. As a result, it is possible to determine the actual rotational position of the cam while avoiding the occurrence of a valve stamp.

  When the operating angles of the intake valve and the exhaust valve are determined as described above, the valve overlap amount greatly differs between the case where the temporary determination result is correct and the case where the temporary determination result is incorrect. In other words, the intake air amount of the internal combustion engine differs greatly between when the temporary determination result is correct and when the temporary determination result is incorrect.

  Therefore, if the operating angles of the intake valve and the exhaust valve are determined as described above, a clear difference appears in the intake air amount of the internal combustion engine between when the temporary determination result is correct and when the temporary determination result is incorrect. As a result, the actual rotational position of the cam can be determined more accurately.

  The invention described above is effective when the cam position sensor is attached to only one of the intake cam and the exhaust cam, or when one of the intake cam and exhaust cam is broken. . However, if the rotational positions of both the intake cam and exhaust cam cannot be specified (if no cam position sensor is attached to either the intake cam or exhaust cam, or the cam positions of both the intake cam and exhaust cam) When the sensor has failed), it is difficult to determine the rotational position of the cam based only on the physical quantity acquired by the acquisition unit.

For example, the intake air amount of the internal combustion engine is substantially the same when the temporary determination result regarding the rotational positions of the intake cam and exhaust cam is incorrect and when the temporary determination result regarding the rotational positions of the intake cam and exhaust cam is correct. . Further, the intake air amount of the internal combustion engine is substantially equal between the case where only the temporary determination result regarding the rotational position of the intake cam is incorrect and the case where only the temporary determination result regarding the rotational position of the exhaust cam is incorrect. For this reason, it is difficult to specify the rotational positions of the intake cam and the exhaust cam based on the physical quantity acquired by the acquisition means.

  In contrast, the valve operating system for an internal combustion engine of the present invention is provided with a sub-acquisition means for acquiring a physical quantity correlated with the intake amount of the specific cylinder in a specific cylinder among a plurality of cylinders included in the internal combustion engine, The rotational positions of the intake cam and the exhaust cam are specified based on the acquired value of the sub acquisition means.

  Specifically, first, the specifying unit specifies a plurality of rotational positions that can be taken by the intake cam of the specific cylinder with respect to the detection position of the detection unit. Subsequently, the temporary determination means assumes that one of the plurality of rotational positions specified by the specifying means is the rotational position of the cam of the specific cylinder so that the cam of the specific cylinder operates. Activate the prime mover.

  At that time, the acquired value (intake air amount of the specific cylinder) of the sub-acquisition means when the specific cylinder is in the intake stroke increases only when the provisional determination result regarding the rotational positions of the intake cam and the exhaust cam is correct. Therefore, the determination unit can specify the actual rotational position of the intake cam based on the acquired value of the sub acquisition unit.

  Thus, when the actual rotational position of the intake cam is specified, the actual rotational position of the exhaust cam can also be specified based on the physical quantity correlated with the intake air amount of the internal combustion engine as described above.

  The physical quantity correlated with the intake air amount of the specific cylinder can be exemplified by the amount of air passing through the intake port of the specific cylinder, the pressure in the intake port of the specific cylinder, or the like. For this reason, the sub-acquisition means can be realized by an air flow meter, a pressure sensor or the like attached to the intake port of the specific cylinder.

  In the present invention, the timing for determining the operation of the prime mover by the temporary determination means and the rotational position of the cam by the determination means is the time when the fuel injection is started at the start of the internal combustion engine or when the cam position sensor has failed. Etc. can be illustrated.

  According to the present invention, in 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 drives the valve to open and close, the rotational position of the cam can be detected even when the cam position sensor fails. Can be determined.

  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 an internal combustion engine to which the present invention is applied. 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. An air flow meter 61 and a fuel injection valve 12 are 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) introduced from the intake port 6 into the cylinder 2 are ignited and burned by the spark plug 13 provided in the cylinder 2. 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, an ignition switch 17, and an air flow meter 61.

  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, # 1, # 2, # 3, and # 4 represent the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder 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 a valve spring 87, 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. The speed reduction ratio of the first speed reduction mechanism is “2” (speed ratio at which the first motor 18 rotates twice per 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 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 meshes with the second output gear 22 fixed to the output shaft of the second motor 21. Hereinafter, the second driven gear 86 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.

  A first resolver 20 for detecting the rotation angle of the output shaft of the first motor 18 is attached to the first motor 18 described above. A second resolver 23 that detects the rotation angle of the output shaft of the second motor 21 is attached to the second motor 21 described above. The detection signals of the first resolver 20 and the second resolver 23 are input to the ECU 14. In addition, the 1st resolver 20 and the 2nd resolver 23 are corresponded to the detection means concerning this invention.

  A first cam position sensor 30 is attached to the first intake camshaft 83, and a second cam position sensor 31 is attached to the second intake camshaft 84. The 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 the exhaust valve 9. The exhaust valve 9 is biased in the valve closing direction by a valve spring 94, and the valve lifter 90 is pressed against the exhaust cam 91 by the biasing 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 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. The reduction ratio of the third reduction mechanism is equivalent to that of the first and second reduction mechanisms described above.

  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.

  A third resolver 26 that detects the rotation angle of the output shaft of the third motor 24 is attached to the third motor 24. A detection signal of the third resolver 26 is input to the ECU 14. The third resolver 26 corresponds to detection means according to the present invention.

  A third cam position sensor 32 is attached to the exhaust camshaft 92. The output signal of the third cam position sensor 32 is input to the ECU 14.

In the valve train configured as described above, the ECU 14 rotates the first motor 18, the second motor 21, and the third motor 24 at a timing synchronized with the rotation of the crankshaft 5 (operation that continuously rotates in one direction) or By swinging (an operation in which rotation in one direction and rotation in the opposite direction are repeated alternately), the intake valve 8 and the exhaust valve 9 of the first cylinder (# 1) to the fourth cylinder (# 4) It can be opened and closed at a timing synchronized with the rotation of the crankshaft 5.

  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, a first intake cam 81 (first intake camshaft 83) when the internal combustion engine 1 is started, It is necessary to detect the rotational positions (phases) of the second intake cam 82 (second intake camshaft 84) and the exhaust cam 91 (exhaust camshaft 92).

  As a method for detecting the rotational positions of the first intake cam 81 (first intake camshaft 83), the second intake cam 82 (second intake camshaft 84), and the exhaust cam 91 (exhaust camshaft 92), A method using the detection signals of the resolver 20, the second resolver 23, and the third resolver 26 is conceivable.

  According to this method, the rotational speed ratio between the first intake camshaft 83 and the output shaft of the first motor 18, the rotational speed ratio between the second intake camshaft 84 and the output shaft of the second motor 21, and the exhaust camshaft 92 and the first output shaft. 3 When the rotational speed ratio of the output shaft of the motor 24 is “1” (each motor rotates once while each camshaft rotates once), the rotational position (phase) of each camshaft is specified. Can do.

  However, when a speed reduction mechanism is interposed between each camshaft and each motor, each camshaft can take a plurality of rotational positions with respect to one rotational position of each motor output shaft. For example, as illustrated in the present embodiment, when the rotation speed ratio of the motor output shaft to the camshaft is 2 (when the motor output shaft rotates twice while the camshaft rotates once), 1 of the motor output shaft The camshaft can take two rotational positions for one rotational position.

  FIG. 4 is a diagram showing the relationship between the rotational position of the first intake cam 81 and the rotational position of the output shaft of the first motor 18 (detection signal of the first resolver 20). In FIG. 4, the rotation speed ratio of the output shaft of the first motor 18 to the first intake camshaft 83 is 2 (the output shaft of the first motor 18 rotates twice while the first intake camshaft 83 makes one rotation). is there.

  In this case, since the output shaft of the first motor 18 rotates twice while the first intake camshaft 83 rotates once, the first intake camshaft 83 (first intake camshaft 83 relative to one rotational position of the first motor 18). The cam 81) can take two rotational positions.

  Therefore, the rotational position of the first intake camshaft 83 (first intake cam 81) cannot be specified only from the detection signal of the first resolver 20. In other words, it is possible to determine whether the rotational position of the first motor 18 belongs to the range of 0 ° to 360 ° or the range of 360 ° to 720 ° based only on the detection signal of the first resolver 20. Can not.

  On the other hand, in the valve operating system of the present embodiment, the ECU 14 determines the rotation position of each camshaft (the rotation position of each motor from 0 ° based on the detection signal of each resolver and the detection signal of each cam position sensor). Whether it belongs to the range of 360 ° or belongs to the range of 360 ° to 720 °).

For example, as shown in FIG. 4, the first cam position sensor 30 has a first intake camshaft 83 in a range of 180 ° to 360 ° when the first motor 18 belongs to a range of 360 ° to 720 °. What is necessary is just to be comprised so that "1" may be output when it belongs. Moreover, the 2nd cam position sensor 31 and the 3rd cam position sensor 32 should just be comprised similarly.

  By referring to the detection signal of the cam position sensor and the detection signal of the resolver configured as described above, the ECU 14 can uniquely identify the rotational position of each camshaft (each cam).

  By the way, if any one of the three cam position sensors 30, 31, 32 fails, it becomes impossible to specify the rotational position of the camshaft corresponding to the failed cam position sensor.

  Therefore, the ECU 14 specifies the rotational position of the camshaft based on a physical quantity that correlates with the intake air amount of the internal combustion engine 1 when any of the cam position sensors 30, 31, 32 fails. Examples of the physical quantity correlated with the intake air quantity of the internal combustion engine 1 include the intake air quantity Ga (detection signal of the air flow meter 61) and the pressure of the intake pipe. Here, an example using the intake air quantity Ga is used. Is described.

  First, when the first cam position sensor 30 fails, the ECU 14 first reads the detection signal mp1 of the first resolver 20. In this case, the rotation position of the first intake camshaft 83 can take two rotation positions of cp11 (= mp / 2) and cp12 (= (mp + 360) / 2) as shown in FIG.

  Therefore, the ECU 14 tentatively determines that one of cp11 and cp12 is the actual rotational position of the first intake camshaft 83 (hereinafter, the temporarily determined rotational position is referred to as “temporary determination position cprp1”). The actual rotational position cpr2 of the second intake camshaft 84 and the actual rotational position cpr3 of the exhaust camshaft 92 are detected signals from the second resolver 23 and the second cam position sensor 31, and the third resolver 26 and the third cam. It is assumed that the determination is made as usual based on the detection signal with the position sensor 32.

  Subsequently, the ECU 14 controls the first motor 18 and the third motor 24 to rotate the first intake camshaft 83 and the exhaust camshaft 92 during cranking of the internal combustion engine 1. At this time, the ECU 14 controls the first motor 18 and the third motor 24 so that the first intake camshaft 83 and the exhaust camshaft 92 are synchronized with the crankshaft 5 according to the temporary determination position cprp1 and the actual rotation position cpr3. To do. The third motor 24 is controlled so that the exhaust valve 9 opens for two strokes from the expansion stroke to the exhaust stroke.

  The ECU 14 monitors the detection signal (intake air amount) Ga of the air flow meter 61 when the first intake camshaft 83 and the exhaust camshaft 92 are rotating. Here, FIG. 6 shows a change in the intake air amount Ga when the provisional determination position cprp1 of the first intake camshaft 83 coincides with the actual rotation position. The solid line in FIG. 6 indicates the phase of the intake valve 8 and the dashed line indicates the phase of the exhaust valve 9. As shown in FIG. 6, when the provisional determination position cprp1 coincides with the actual rotation position, the intake air amount in the intake stroke of the first cylinder (# 1) and the intake stroke of the fourth cylinder (# 4). Ga increases.

  On the other hand, when the temporary determination position cprp1 does not coincide with the actual rotation position, the intake valves 8 of the first cylinder (# 1) and the fourth cylinder (# 4) are opened during the expansion stroke, as shown in FIG. It will be. During the expansion stroke of the first cylinder (# 1) and the fourth cylinder (# 4), the exhaust valve 9 is also opened, so that gas is sucked into the cylinder 2 from both the intake port 6 and the exhaust port 7. As a result, the intake air amount Ga hardly increases when the intake valve 8 is opened.

Therefore, the ECU 14 obtains an integrated value (hereinafter referred to as “integrated intake air amount”) ΣGa of the intake air amount Ga in a predetermined period, and compares the integrated intake air amount ΣGa with a normal value. Whether the determination position cprp1 is correct is determined.

  The predetermined period is set to a period in which the first intake camshaft 83 rotates at least once, or a period in which the crankshaft 5 rotates at least twice. The normal value described above corresponds to the integrated intake air amount ΣGa when the provisional determination position cprp1 coincides with the actual rotation position, and is assumed to be experimentally obtained in advance.

  The ECU 14 determines that the temporary determination position cprp1 matches the actual rotation position when the difference between the integrated intake air amount ΣGa and the normal value is equal to or less than the allowable value, and sets the temporary determination position cprp1 to the actual rotation position cpr1. To do.

  On the other hand, when the difference between the cumulative intake air amount ΣGa and the normal value exceeds the allowable value, the ECU 14 determines that the temporary determination position cprp1 does not coincide with the actual rotation position. In that case, the ECU 14 sets one of the two rotational positions cp11 and cp12 as the actual rotational position cpr1.

  In addition, instead of the integrated intake air amount ΣGa described above, the intake air amount Ga increases at the timing when the intake air amount Ga increases (in other words, during the intake stroke of the first cylinder (# 1) and the fourth cylinder (# 4)). Whether or not the temporary determination position cprp1 is correct may be determined using parameters such as the maximum value of the intake air amount Ga.

  Further, the second intake camshaft 84 may be rotated during the predetermined period. According to this, since the fuel injection and the ignition can be started after a predetermined period, the internal combustion engine 1 can be started immediately. On the other hand, the second intake camshaft 84 may not be rotated during the predetermined period. According to this, the difference in the cumulative intake air amount ΣGa between the case where the provisional determination position cprp1 is coincident with the actual rotation position and the case where the provisional determination position cprp1 is different from the actual rotation position becomes significant, thereby improving the determination accuracy. be able to.

  Next, when the second cam position sensor 31 fails, the ECU 14 first determines the temporary determination position cprp2 of the second intake camshaft 84 by the same procedure as that when the first cam position sensor 30 fails. . Then, the ECU 14 controls the second motor 21 and the third motor 24 to rotate the second intake camshaft 84 and the exhaust camshaft 92 during cranking of the internal combustion engine 1.

  FIG. 8 shows a change in the intake air amount Ga when the provisional determination position cprp2 of the second intake camshaft 84 coincides with the actual rotational position. In FIG. 8, the intake valve 8 opens in the intake stroke of the second cylinder (# 2) and the third cylinder (# 3), and the exhaust valve 9 opens in the second cylinder (# 2) and the third cylinder (# 3). The valve is opened from the expansion stroke to the exhaust stroke. Therefore, the intake air amount Ga significantly increases in the intake stroke of the second cylinder (# 2) and the third cylinder (# 3).

  On the other hand, if the provisional determination position cprp2 of the second intake camshaft 84 does not coincide with the actual rotational position, the intake valve 8 has the second cylinder (# 2) and the third cylinder (#) as shown in FIG. The valve is opened in the expansion stroke of 3), and the exhaust valve 9 is opened in the exhaust stroke from the expansion stroke of the second cylinder (# 2) and the third cylinder (# 3). That is, in the expansion strokes of the second cylinder (# 2) and the third cylinder (# 3), the valve opening period of the intake valve 8 and the valve opening period of the exhaust valve 9 overlap. Therefore, the intake air amount Ga hardly increases not only in the intake stroke of the second cylinder (# 2) and the third cylinder (# 3) but also in the expansion stroke.

Therefore, the ECU 14 can determine the correctness of the temporary determination position cprp2 by determining the integrated intake air amount ΣGa during a predetermined period and comparing the integrated intake air amount ΣGa with a normal value, and the determination result. The actual rotational position cpr2 can also be specified according to the above.

  When the third cam position sensor 32 fails, the ECU 14 first determines the temporary determination position cprp3 of the exhaust camshaft 92 by the same procedure as that when the first cam position sensor 30 fails. The ECU 14 then rotates the first intake camshaft 83 (or the second intake camshaft 84) and the exhaust camshaft 92 during the cranking of the internal combustion engine 1 to rotate the first motor 18 (or the second motor 21). And the third motor 24 is controlled.

  Here, when the temporary determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position, as shown in FIG. 6 (or FIG. 8), the first cylinder (# 1) and the fourth cylinder In the intake stroke of (# 4) (or the second cylinder (# 2) and the fourth cylinder (# 4)), the intake air amount Ga significantly increases.

  On the other hand, when the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position, as shown in FIGS. 10 and 11, the first cylinder (# 1) and the fourth cylinder (# 4) (or In the intake stroke of the second cylinder (# 2) and the fourth cylinder (# 4)), the intake air amount Ga hardly increases.

  Therefore, the ECU 14 can determine the correctness of the temporary determination position cprp3 by determining the integrated intake air amount ΣGa during a predetermined period and comparing the integrated intake air amount ΣGa with a normal value, and the determination result. Based on the actual rotational position cpr3 can be specified.

  As described above, when any one of the three cam position sensors 30, 31, 32 fails, the cam shaft in which the cam position sensor has failed based on the physical quantity correlated with the intake air amount of the internal combustion engine 1. It is possible to uniquely identify the actual rotational position of the.

  Even when any two of the three cam position sensors 30, 31, 32 fail, the rotational position of the camshaft where the cam position sensor has failed is uniquely specified based on the intake air amount of the internal combustion engine 1. It is possible.

  For example, when the first cam position sensor 30 and the second cam position sensor 31 fail, the ECU 14 first determines the first intake camshaft 83 and the first intake camshaft 83 based on the detection signals of the first resolver 20 and the second resolver 23. 2 The temporary determination positions cprp1 and cprp2 of the intake camshaft 84 are determined.

  The ECU 14 determines the integrated intake air amount ΣGa by rotating only the first intake camshaft 83 and the exhaust camshaft 92 during cranking of the internal combustion engine 1. Then, the ECU 14 determines whether the temporary determination position cprp1 of the first intake camshaft 83 is correct by comparing the integrated intake air amount ΣGa and a normal value, and based on the determination result, the first intake camshaft. The actual rotation position cpr1 of 83 is specified.

  When the actual rotational position cpr1 of the first intake camshaft 83 is specified in this manner, the ECU 14 rotates the second intake camshaft 84 and the exhaust camshaft 92 to obtain the integrated intake air amount ΣGa. Next, the ECU 14 determines whether the temporary determination position cprp2 of the second intake camshaft 84 is correct by comparing the cumulative intake air amount ΣGa with a normal value, and based on the determination result, the second intake camshaft. The actual rotation position cpr2 of 84 is specified.

  In the example described above, the ECU 14 specifies the actual rotation position cpr2 of the second intake camshaft 84 after specifying the actual rotation position cpr1 of the first intake camshaft 83, but the actual rotation of the second intake camshaft 84 is determined. The actual rotational position cpr1 of the first intake camshaft 83 may be specified after specifying the position cpr2.

  Next, when the first cam position sensor 30 and the third cam position sensor 32 fail, the ECU 14 first determines the first intake camshaft 83 and the first intake camshaft 83 based on the detection signals of the first resolver 20 and the third resolver 26. Temporary determination positions cprp1 and cprp3 of the exhaust camshaft 92 are determined.

  During cranking of the internal combustion engine 1, the ECU 14 rotates only the second intake camshaft 84 and the exhaust camshaft 92 based on the temporary determination positions cprp1 and cprp3 described above to obtain the integrated intake air amount ΣGa. The ECU 14 compares the cumulative intake air amount ΣGa with a normal value to determine whether the temporary determination position cprp3 of the exhaust camshaft 92 is correct or not, and based on the determination result, the actual rotation of the exhaust camshaft 92 is determined. The position cpr3 is specified.

  When the actual rotation position cpr3 of the exhaust camshaft 92 is specified in this way, the ECU 14 rotates the first intake camshaft 83 and the exhaust camshaft 92 to obtain the integrated intake air amount ΣGa. Then, the ECU 14 determines whether the temporary determination position cprp1 of the first intake camshaft 83 is correct by comparing the integrated intake air amount ΣGa and a normal value, and based on the determination result, the first intake camshaft. The actual rotation position cpr1 of 83 is specified.

  If the second cam position sensor 31 and the third cam position sensor 32 fail, first the actual rotation of the exhaust camshaft 92 is the same as when the first cam position sensor 30 and the third cam position sensor 32 fail. The position cpr3 may be specified, and then the actual rotational position cpr2 of the second intake camshaft 84 may be specified.

  As described above, according to the valve operating system of the internal combustion engine of the present embodiment, when the actual rotation position of at least one camshaft among the plurality of camshafts can be specified, the actual rotation of the remaining camshafts The position can be specified without depending on the cam position sensor.

  As a result, if one of the plurality of cam position sensors is normal, the rotational positions of all the camshafts can be specified. Further, when the valve operating system for the internal combustion engine according to the present embodiment is used, if the cam position sensor is provided on one camshaft among the plurality of camshafts, the rotational positions of all the camshafts can be specified. It is. Therefore, the number of cam position sensors can be reduced.

  Hereinafter, the procedure for specifying the actual rotational position of the camshaft in this embodiment will be described with reference to FIG. FIG. 12 is a flowchart showing a control routine executed by the ECU 14 when the actual rotational position of the camshaft is specified. This control routine is stored in advance in the ROM of the ECU 14 and is executed when the internal combustion engine 1 is started by the ECU 14 (for example, when the ignition switch is switched from OFF to ON).

  In the control routine of FIG. 12, the ECU 14 first executes the process of S101. That is, the ECU 14 determines whether or not all the cam position sensors are normal in S101. If an affirmative determination is made in S101, the ECU 14 proceeds to S102.

In S102, the ECU 14 specifies the actual rotational position cpr of each camshaft based on the detection signal of each cam position sensor and the detection signal of each resolver, and ends the execution of this routine.

  On the other hand, if a negative determination is made in S101, the ECU 14 proceeds to S103. In S103, the ECU 14 specifies a plurality of rotational positions that can be taken by a camshaft in which the cam position sensor has failed (hereinafter, referred to as “failed camshaft”). Specifically, the ECU 14 reads a detection signal of a resolver (resolver attached to a motor for rotating the failed camshaft) corresponding to the failed camshaft. Next, the ECU 14 specifies a plurality of rotational positions that can be taken by the failed camshaft with respect to the detection signal of the resolver. Thus, the specific means concerning this invention is implement | achieved when ECU14 performs the process of S103.

  In S104, the ECU 14 sets one of the plurality of rotational positions specified in S103 as the temporary determination position cprp. At that time, it does not matter which of the plurality of rotational positions is selected as the temporary determination position cprp.

  In S105, the ECU 14 should rotate at least one of the camshafts whose actual rotational position cpr has already been specified (hereinafter referred to as “normal camshaft”) and the failed camshaft at a timing synchronized with the crankshaft 5. Control the motor. At this time, if the failed camshaft is the intake camshaft, the exhaust camshaft is selected as the normal camshaft. On the other hand, if the failed camshaft is the exhaust camshaft, the intake camshaft is selected as the normal camshaft.

  When the ECU 14 executes the processes of S104 and S105 described above, the provisional determination unit according to the present invention is realized.

  In S106, the ECU 14 detects the air flow meter 61 until a predetermined period elapses from the time when the process of S105 is executed (specifically, when the camshaft and the crankshaft start to rotate at timing synchronized with each other). By integrating the signals, an integrated intake air amount ΣGa is obtained.

  In S107, the ECU 14 determines whether or not the absolute value (= | ΣGa−ΣGas |) of the difference between the integrated intake air amount ΣGa obtained in S106 and the normal value ΣGas obtained in advance is equal to or less than the allowable value α. Is determined. If an affirmative determination is made in S107, the ECU 14 proceeds to S108.

  In S108, the ECU 14 sets the temporary determination position cprp specified in S104 to the actual rotation position cpr, and ends the execution of this routine. If there are a plurality of failed camshafts, the ECU 14 may return to S103.

  If a negative determination is made in S107, the ECU 14 proceeds to S109. In S109, the ECU 14 changes the temporary determination position cprp of the failed camshaft. For example, when the first cam position sensor 30 is out of order, one of the two rotation positions cp11 and cp12 that the first intake camshaft 83 can take is set as the temporary determination position cprp1 in S103. If it is set, the ECU 14 may set the other rotational position cp12 to the temporary determination position cprp1 in S109.

  Subsequently, the ECU 14 proceeds to S110, rotates the camshaft in accordance with the temporary determination position cprp set in S109, and acquires the integrated intake air amount ΣGa again.

  In S111, the ECU 14 determines whether or not the absolute value of the difference between the integrated intake air amount ΣGa and the normal value ΣGas acquired in S110 is equal to or less than an allowable value α. If a negative determination is made in S111, the ECU 14 returns to S109. On the other hand, if an affirmative determination is made in S111, the ECU 14 proceeds to S112, and sets the temporary determination position cprp set in S109 to the actual rotation position cpr.

  Here, when the ECU 14 executes S106 and / or S110 described above, the acquisition means according to the present invention is realized. Further, the ECU 14 executes the processing from S107 to S108 and / or the processing from S111 to S112, thereby realizing the determination means according to the present invention.

  When the speed reduction ratio of the speed reduction mechanism is “2”, the processing from S109 to S112 in FIG. 12 may be omitted. It is determined that one of the two rotational positions that the camshaft can take with respect to the resolver detection signal (the rotational position set as the temporary determination position in S104) does not match the actual rotational position. This is because it is possible to specify that the other rotational position of the two rotational positions described above is the actual rotational position (if a negative determination is made in S107).

<Example 2>
Next, a second embodiment of the valve operating system for an internal combustion engine according to 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 rotational position of another camshaft is specified under the condition that at least one rotational position of three camshafts can be specified has been described. In this embodiment, three camshafts are specified. An example will be described in which the rotational position of each camshaft is specified under conditions in which any rotational position of the shaft cannot be specified.

  FIG. 13 shows the first intake camshaft in a state where the temporary determination position cprp1 of the first intake camshaft 83 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position. FIG. 8 is a diagram showing a change in intake air amount Ga when 83 and exhaust camshaft 92 are rotated.

  In FIG. 13, since only the intake valve 8 is opened in the expansion strokes of the first cylinder (# 1) and the fourth cylinder (# 4), the intake air amount Ga is remarkably increased. The integrated intake air amount ΣGa in this case is determined when the temporary determination position cprp1 of the first intake camshaft 83 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 matches the actual rotation position (for example, FIG. 6)). Further, in both cases, the increase timing of the intake air amount Ga and the maximum value of the intake air amount Ga are substantially the same.

  Similarly, the temporary determination position cprp2 of the second intake camshaft 84 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position, and the second intake camshaft 84. Even when the provisional determination position cprp2 of the exhaust camshaft 92 coincides with the actual rotation position and the provisional determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position, the cumulative intake air amount ΣGa, the intake air amount Ga increase timing, and the intake The maximum value of the air amount Ga is substantially equal.

Further, when the temporary determination position cprp1 of the first intake camshaft 83 coincides with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position (see, for example, FIG. 10). Integration is also performed when the temporary determination position cprp1 of the first intake camshaft 83 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position (see FIG. 7). The intake air amount ΣGa, the increase timing of the intake air amount Ga, and the maximum value of the intake air amount Ga are substantially equal.

  Furthermore, when the temporary determination position cprp2 of the second intake camshaft 84 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not match the actual rotation position (see, for example, FIG. 11). Even when the temporary determination position cprp2 of the second intake camshaft 84 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position (see, for example, FIG. 9). , The integrated intake air amount ΣGa, the increase timing of the intake air amount Ga, and the maximum value of the intake air amount Ga are substantially equal.

  Therefore, when none of the rotational positions of the three cam shafts can be specified (for example, when all three cam position sensors fail or when no cam position sensor is provided on any of the three cam shafts). In this case, it is difficult to specify the actual rotational position of the camshaft by the method described in the first embodiment.

  Therefore, in this embodiment, the actual rotational position of each camshaft is specified by detecting a physical quantity that correlates with the intake amount of at least one cylinder (specific cylinder) of the four cylinders 2 of the internal combustion engine 1. I made it.

  Examples of the configuration for detecting the physical quantity correlated with the intake amount of the cylinder 2 include a configuration in which an air flow meter is disposed in the intake port of the specific cylinder, or a configuration in which a pressure sensor is attached to the intake port of the specific cylinder. In this embodiment, a case where an air flow meter is attached to an intake port of a specific cylinder will be described.

  FIG. 14 is a diagram showing a schematic configuration of the internal combustion engine in the present embodiment. In FIG. 14, a sub air flow meter 40 is attached to the intake port 6 of the first cylinder (# 1) of the internal combustion engine 1. The sub air flow meter 40 is electrically connected to the ECU 14, and a detection signal of the sub air flow meter 40 is input to the ECU 14. Other configurations are the same as those of the internal combustion engine 1 described in the first embodiment.

  Next, a procedure for specifying the rotational position of the camshaft using the sub air flow meter 40 will be described.

  First, the ECU 14 specifies the temporary determination positions cprp1 and cprp3 of the first intake camshaft 83 and the exhaust camshaft 92 based on detection signals of the first resolver 20 and the third resolver 26.

  Subsequently, the ECU 14 controls the first motor 18 and the third motor 24 to rotate the first intake camshaft 83 and the exhaust camshaft 92 during cranking of the internal combustion engine 1. At this time, the ECU 14 sets the first motor 18 and the third motor 24 so that the first intake camshaft 83 and the exhaust camshaft 92 rotate at a timing synchronized with the crankshaft 5 based on the temporary determination positions cprp1 and cprp3. Control. Further, the ECU 14 sets the operating angles of the first intake cam 81 and the exhaust cam 91 in the same manner as in the first embodiment described above.

The ECU 14 monitors the detection signal of the sub air flow meter 40 and specifies the timing at which the detection signal of the sub air flow meter 40 increases. Here, the results of monitoring the detection signal of the sub air flow meter 40 when the first intake camshaft 83 and the exhaust camshaft 92 are rotated based on the temporary determination positions cprp1 and cprp3 are shown in FIGS.
It is shown in FIG.

  FIG. 15 shows the detection signal Ga1 of the sub airflow meter 40 when the temporary determination position cprp1 of the first intake camshaft 83 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 matches the actual rotation position. Show.

  FIG. 16 shows the detection signal Ga1 of the sub air flow meter 40 when the temporary determination position cprp1 of the first intake camshaft 83 does not match the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not match the actual rotation position. Is shown.

  FIG. 17 shows the detection signal Ga1 of the sub air flow meter 40 when the temporary determination position cprp1 of the first intake camshaft 83 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not match the actual rotation position. Show.

  FIG. 18 shows the detection of the sub air flow meter 40 when the provisional determination position cprp1 of the first intake camshaft 83 does not coincide with the actual rotation position and the provisional determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position. The signal Ga1 is shown.

  Referring to FIGS. 15 to 18, when the temporary determination position cprp1 of the first intake camshaft 83 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 matches the actual rotation position, Only when the temporary determination position cprp1 of the camshaft 83 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position, the detection signal Ga1 of the sub air flow meter 40 increases significantly. Is shown.

  Further, the temporary determination position cprp1 of the first intake camshaft 83 matches the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 matches the actual rotation position, and the temporary determination position of the first intake camshaft 83. The increase timing of the detection signal Ga1 of the sub air flow meter 40 is different from the case where cprp1 does not coincide with the actual rotation position and the provisional determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position.

  That is, when the provisional determination position cprp1 of the first intake camshaft 83 coincides with the actual rotation position and the provisional determination position cprp3 of the exhaust camshaft 92 coincides with the actual rotation position, the detection signal Ga1 of the sub air flow meter 40 is 1. It increases in the intake stroke of the No. cylinder (# 1). On the other hand, when the temporary determination position cprp1 of the first intake camshaft 83 does not coincide with the actual rotation position and the temporary determination position cprp3 of the exhaust camshaft 92 does not coincide with the actual rotation position, the detection signal of the sub air flow meter 40 Ga1 increases in the expansion stroke of the first cylinder (# 1).

  Therefore, when the detection signal Ga1 of the sub air flow meter 40 increases in the intake stroke of the first cylinder (# 1), the ECU 14 determines that the temporary determination positions cprp1 and cprp3 coincide with the actual rotation position. it can. In that case, the ECU 14 may set the temporary determination positions cprp1 and cprp3 to the actual rotation positions cpr1 and cpr3.

  Further, when the detection signal Ga1 of the sub air flow meter 40 increases in the expansion stroke of the first cylinder (# 1), the ECU 14 determines that both the temporary determination positions cprp1 and cprp3 do not coincide with the actual rotation position. be able to. In that case, the ECU 14 determines that the rotation position that is not selected as the temporary determination positions cprp1 and cprp3 among the two rotation positions that the first intake camshaft 83 and the exhaust camshaft 92 can take coincides with the actual rotation position. can do.

In addition, the ECU 14 detects that the detection signal Ga1 of the sub air flow meter 40 is the first cylinder (# 1).
If it does not increase during the intake stroke and the expansion stroke, it can be determined that one of the temporary determination positions cprp1 and cprp3 does not coincide with the actual rotation position. In that case, the ECU 14 changes one of the temporary determination positions cprp1 and cprp3 to rotate the first intake camshaft 83 and the exhaust camshaft 92, and monitors the detection signal Ga1 of the sub airflow meter 40 at that time. Good. As a result, the detection signal Ga1 of the sub air flow meter 40 shows a significant increase in either the intake stroke or the expansion stroke of the first cylinder (# 1), so which of the temporary determination positions cprp1 and cprp3 is the actual rotational position cpr1 , Cpr3 (in other words, which of the temporary determination positions cpr1, cpr3 does not coincide with the actual rotation positions cpr1, cpr3) can be identified.

  After the actual rotational positions cpr1 and cpr3 of the first intake camshaft 83 and the exhaust camshaft 92 are specified in this way, the ECU 14 performs the second intake camshaft 84 by the same method as in the first embodiment described above. The rotational position of can be specified.

  Therefore, according to the valve operating system for the internal combustion engine of the present embodiment, it is possible to specify the actual rotational position of each camshaft even under conditions in which any rotational position of the plurality of camshafts cannot be specified. .

  As a result, even when all of the plurality of cam position sensors have failed, the rotational positions of all the camshafts can be specified. Further, when the valve operating system for the internal combustion engine of the present embodiment is used, the rotational positions of all the camshafts can be specified even when no cam position sensor is provided on any of the plurality of camshafts. . Therefore, the number of parts of the valve operating system can be reduced.

  Hereinafter, a procedure for specifying the rotational position of each camshaft in the present embodiment will be described with reference to FIG. FIG. 19 is a flowchart showing a control routine executed by the ECU 14 when the actual rotational position of the camshaft is specified. This control routine is stored in advance in the ROM of the ECU 14 and is executed when the internal combustion engine 1 is started by the ECU 14 (for example, when the ignition switch is switched from OFF to ON).

  In the control routine of FIG. 19, the ECU 14 first executes the process of S201. That is, the ECU 14 determines whether or not there is a normal cam position sensor in S201. If an affirmative determination is made in S201, the ECU 14 proceeds to S202 and executes a determination process based on the detection signal Ga of the air flow meter 61. That is, the ECU 14 specifies the rotational position of the camshaft by the same procedure (for example, see FIG. 12) as in the first embodiment described above. However, when all the cam position sensors are normal, the actual rotational position of each camshaft is specified based on the detection signals of the cam position sensor and the resolver.

  If a negative determination is made in S201, the ECU 14 proceeds to S203. In S203, the ECU 14 takes the two rotational positions cp11, cp12 that the first intake camshaft 83 can take and the exhaust camshaft 92 based on the detection signal of the first resolver 20 and the detection signal of the third resolver 26. Two rotational positions cp31 and cp32 to be obtained are specified.

  In S204, the ECU 14 sets one rotation position cp11 of the rotation positions cp11 and cp12 of the first intake camshaft 83 specified in S203 as the temporary determination position cprp1, and the exhaust camshaft specified in S203. One rotational position cp31 of the 92 rotational positions cp31, cp32 is set as a temporary determination position cprp3. Note that it does not matter which of the two rotational positions is selected as the temporary determination position.

  In S205, the ECU 14 determines that the first motor 18 and the exhaust camshaft 83 rotate at a timing synchronized with the crankshaft 5 based on the temporary determination positions cprp1 and cprp3 set in S204. The third motor 24 is controlled.

  In S206, the ECU 14 monitors the detection signal Ga1 of the sub air flow meter 40. Subsequently, in S207, the ECU 14 determines whether or not the detection signal Ga1 of the sub air flow meter 40 has increased in the intake stroke of the first cylinder (# 1). That is, the ECU 14 determines whether or not the detection signal Ga1 of the sub air flow meter 40 has increased at the timing shown in FIG.

  If an affirmative determination is made in S207, the ECU 14 proceeds to S208. In S208, the ECU 14 sets the temporary determination positions cprp1 and cprp3 set in S204 to the actual rotational positions cpr1 and cpr3. Thereafter, the ECU 14 proceeds to S202, and specifies the actual rotational position cpr2 of the second intake camshaft 84 by the method described in the first embodiment.

  If a negative determination is made in S207, the ECU 14 proceeds to S209. In S209, the ECU 14 determines whether or not the detection signal Ga1 of the sub air flow meter 40 has increased in the expansion stroke of the first cylinder (# 1). That is, the ECU 14 determines whether or not the detection signal Ga1 of the sub air flow meter 40 has increased at the timing shown in FIG.

  If an affirmative determination is made in S209, the ECU 14 proceeds to S210. In S210, the ECU 14 determines that both of the temporary determination positions cprp1 and cprp3 set in S204 do not coincide with the actual rotation position, and determines the rotation positions cp12 and cp32 specified in S203 as the actual rotation positions cpr1, Set to cpr3. Thereafter, the ECU 14 proceeds to S202, and specifies the actual rotational position cpr2 of the second intake camshaft 84 by the same method as in the first embodiment described above.

  On the other hand, if a negative determination is made in S209, the ECU 14 proceeds to S211. In S211, the ECU 14 determines that one of the temporary determination positions cprp1 and cprp3 set in S204 does not match the actual rotation position, and changes one of the temporary determination positions cprp1 and cprp3. To do. Then, the ECU 14 executes the processes after S205 again. In that case, the detection signal Ga1 of the sub air flow meter 40 increases in the intake stroke or the expansion stroke of the first cylinder (# 1). As a result, the actual rotational positions of the first intake camshaft 83 and the exhaust camshaft 92 can be specified.

  As described above, the ECU 14 executes the control routine of FIG. 19, so that the actual rotational position of each camshaft can be identified even when any rotational position of the three camshafts cannot be identified.

  In this embodiment, an example in which the sub air flow meter 40 is attached to the intake port 6 of the first cylinder (# 1) has been described. However, the second cylinder (# 2), the third cylinder (# 3), or 4 A sub air flow meter 40 may be attached to the intake port 6 of the numbered cylinder (# 4). However, when the sub air flow meter 40 is attached to the intake port 6 of the second cylinder (# 2) or the third cylinder (# 3), the second intake is used instead of the first intake camshaft 83 in the control routine of FIG. It is assumed that the camshaft 84 is rotated. In short, the rotational position of each camshaft may be specified by rotating the camshaft that opens and closes the intake valve 8 of the cylinder 2 to which the sub air flow meter 40 is attached and the exhaust camshaft 92.

1 is a diagram showing a schematic configuration of an internal combustion engine to which the present invention is applied. 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 detection signal of a 1st resolver, the rotation position of a 1st intake camshaft, and the detection signal of a 1st cam position sensor. It is a figure which shows the rotation position which a 1st intake camshaft can take with respect to the detection signal of a 1st resolver. It is a figure which shows the change of the intake air amount in case the temporary determination position of a 1st intake camshaft corresponds with an actual rotational position. It is a figure which shows the change of the intake air amount in case the temporary determination position of a 1st intake camshaft does not correspond with an actual rotational position. It is a figure which shows the change of the intake air amount in case the temporary determination position of a 2nd intake camshaft corresponds with an actual rotational position. It is a figure which shows the change of the intake air amount in case the temporary determination position of a 2nd intake camshaft is not in agreement with an actual rotation position. It is a 1st figure which shows the change of the intake air amount in case the temporary determination position of an exhaust camshaft is not in agreement with an actual rotation position. FIG. 10 is a second diagram illustrating a change in the intake air amount when the temporary determination position of the exhaust camshaft does not coincide with the actual rotation position. It is a flowchart which shows the control routine for pinpointing the rotational position of a camshaft in a 1st Example. It is a figure which shows the change of the intake air amount in case the temporary determination position of a 1st intake camshaft does not correspond to an actual rotation position, and the temporary determination position of an exhaust camshaft does not correspond to an actual rotation position. It is a figure which shows schematic structure of the internal combustion engine in a 2nd Example. It is a figure which shows the detection signal of a sub air flow meter in case the temporary determination position of a 1st intake camshaft corresponds to an actual rotation position, and the temporary determination position of an exhaust camshaft corresponds to an actual rotation position. It is a figure which shows the detection signal of a sub air flow meter in case the temporary determination position of a 1st intake camshaft does not correspond to an actual rotation position, and the temporary determination position of an exhaust camshaft does not correspond to an actual rotation position. It is a figure which shows the detection signal of a sub air flow meter in case the temporary determination position of a 1st intake camshaft corresponds to an actual rotation position, and the temporary determination position of an exhaust camshaft does not correspond to an actual rotation position. It is a figure which shows the detection signal of a sub air flow meter in case the temporary determination position of a 1st intake cam shaft does not correspond to an actual rotation position, and the temporary determination position of an exhaust camshaft corresponds to an actual rotation position. It is a flowchart which shows the control routine for pinpointing the rotational position of a camshaft in a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 3 ... Piston 4 ... Connecting rod 5 ... Crankshaft 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 ... Spark plug 15 ... Crank position sensor 16 ... Water temperature sensor 17 ... Ignition switch 18 ... Motor 19 ... First output gear 20 ... Resolver 21 ... Second motor 22 ... Second output gear 23 ... Second resolver 24 ... third motor 25 ... third output gear 26 ... third resolver 30 ... first cam position sensor 31 ... second cam position sensor 32 ... third cam position sensor 40- ..Sub airf -Meter 60 ... intake passage 61 ... air flow meter 70 ... exhaust passage 80 ... valve lifter 81 ... first intake cam 82 ... second intake cam 83 ... first intake cam shaft 84 ... second intake camshaft 85 ... first driven gear 86 ... second driven gear 87 ... valve spring 90 ... valve lifter 91 ... exhaust cam 92 ... exhaust cam shaft 93 ..Third driven gear 94 ... Valve spring

Claims (5)

In a valve operating system for an internal combustion engine in which a cam driven by a prime mover independent of the internal combustion engine opens and closes the valve,
A speed reduction mechanism for decelerating the rotation of the prime mover and transmitting it to the cam;
Detecting means for detecting a rotational position of the prime mover;
Specifying means for specifying a plurality of rotational positions that the cam can take with respect to the detection value of the detecting means;
Temporary determination means for operating the prime mover on the assumption that one of the plurality of rotation positions specified by the specifying means is the rotation position of the cam;
Obtaining means for obtaining a physical quantity correlated with an intake air quantity of the internal combustion engine when the prime mover is operated by the temporary judging means;
A determination unit that determines whether or not the temporary determination result of the temporary determination unit is correct based on the physical quantity acquired by the acquisition unit, and that determines an actual rotational position of the cam according to the determination result;
A valve operating system for an internal combustion engine, comprising:   2. The working angle of the intake valve and the exhaust valve when the temporary determination unit operates the prime mover according to claim 1, wherein the temporary determination result of the temporary determination unit is wrong when the temporary determination result of the temporary determination unit is correct. A valve operating system for an internal combustion engine, characterized in that the valve overlap amount is determined to be different from that of the internal combustion engine. In Claim 1 or 2, further comprising sub-acquisition means for acquiring a physical quantity correlated with the amount of air sucked into a specific cylinder among the plurality of cylinders of the internal combustion engine,
The specifying means specifies a plurality of rotational positions that can be taken by the cam of the specific cylinder with respect to the detection position of the detecting means,
The temporary determination means assumes that the rotational position of one of the plurality of rotational positions specified by the specifying means is the rotational position of the cam of the specific cylinder so that the cam of the specific cylinder operates. And
The determination unit determines whether the temporary determination result of the temporary determination unit is correct based on the physical quantity acquired by the sub-acquisition unit when the prime mover is operated by the temporary determination unit, and the determination A valve operating system for an internal combustion engine, wherein an actual rotational position of a cam of the specific cylinder is determined based on a result.   4. The operation of the prime mover by the temporary determination unit and the determination by the determination unit according to claim 1, wherein the determination by the determination unit is performed when the internal combustion engine is started and before fuel injection is started. A valve operating system for an internal combustion engine.   5. The valve operating system for an internal combustion engine according to claim 4, wherein the operation of the prime mover by the temporary determination means and the determination by the determination means are performed when a cam position sensor for detecting the rotational position of the cam fails.

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