JP2013217339A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of properly performing both estimation of a crank angle when a crank sensor is abnormal and execution of engine control based on the crank angle.SOLUTION: A control device of an internal combustion engine includes an intake valve timing changing mechanism, an exhaust valve timing changing mechanism, a lock mechanism for locking the intake valve timing in the lock timing, a crank sensor for outputting a crank signal, an intake cam detecting part for outputting an intake cam signal, and an intake cam detecting part for outputting an exhaust cam signal. Detecting accuracy of the intake cam detecting part is set higher than an exhaust cam detecting part. Engine control is executed based on the crank angle detected based on the crank signal and the intake cam signal. When the crank sensor is abnormal (S101: YES), operation control of the intake valve timing changing mechanism based on the exhaust cam signal is executed to put the lock mechanism in a lock state (S104-S106). Besides, the engine control is executed based on an estimated crank angle calculated based on the intake cam signal.

Description

  The present invention relates to a control device for an internal combustion engine including a valve timing changing mechanism that changes a valve timing and a lock mechanism that locks the valve timing at a specific time.

  Normally, in a control device for an internal combustion engine, when a rotation angle (crank angle) of a crankshaft is detected, engine control is executed based on the crank angle. An apparatus for detecting a crank angle includes a disc-shaped crank rotor provided integrally with a crankshaft of an internal combustion engine. A plurality of convex portions are formed on the outer periphery of the crank rotor, and a crank sensor is provided in the vicinity of the crank rotor. A pulse signal (crank signal) is output from the crank sensor every time the convex portion of the crank rotor passes near the crank sensor as the crankshaft rotates. A disc-shaped cam rotor is also integrally attached to the camshaft of the internal combustion engine. A protrusion is formed on the outer periphery of the cam rotor, and a cam sensor is provided in the vicinity of the cam rotor. The cam sensor outputs a signal (cam signal) whose output level changes steeply every time the protrusion of the cam rotor passes near the cam sensor as the cam shaft rotates. These crank signals and cam signals are taken into the electronic control unit. The electronic control unit detects the change timing of the output level of the crank signal and the change timing of the output level of the cam signal. Based on the relationship between the change timings, the crank angle and the camshaft rotation angle (cam Corner).

  In such a device, if any abnormality occurs in the crank sensor, the crank angle cannot be detected, and it is difficult to properly control the operation of the internal combustion engine. For this reason, it has been proposed to estimate the crank angle based only on the cam signal and use it for engine control as fail-safe control when the crank sensor is abnormal (see, for example, Patent Document 1).

  In recent years, it is often used to provide a valve timing changing mechanism in an internal combustion engine. The valve timing changing mechanism changes the intake / exhaust valve opening / closing timing, so-called valve timing, in accordance with the engine operating state in order to improve the fuel efficiency and output performance of the internal combustion engine and reduce emissions.

  In the valve timing changing mechanism described in Patent Document 2, a vane rotor fixed to a camshaft is rotatably accommodated in a housing rotor connected to a crankshaft of an internal combustion engine, and extends in the circumferential direction from the vane rotor. An advance pressure chamber and a retard pressure chamber are defined in the housing by the vane. The vane rotor is rotated by changing the fluid pressure (for example, oil pressure) in these pressure chambers, thereby changing the relative rotation phase of the camshaft with respect to the crankshaft to change the valve timing.

  In the valve timing changing mechanism, the valve timing of the internal combustion engine is set to a predetermined timing that is intermediate between the retard limit (most retarded timing) and the advance limit (most advanced timing). A lock mechanism is provided for regulating at this time (lock time). Specifically, when the vane rotor rotates and the valve timing becomes the lock timing, the lock pin provided in the vane rotor can enter and exit from the recess provided in the housing rotor. In this state, the lock pin of the vane rotor is inserted into the recess of the housing rotor, whereby the rotation of the vane rotor is restricted and the valve timing is restricted at the lock timing (lock state). Further, in this state, the valve pin is allowed to be changed from the recess to allow the valve timing to be changed (unlocked state). In this valve timing control device, the lock mechanism is locked in a predetermined engine operation state such as when the operation of the internal combustion engine is stopped, and the valve timing is locked at the lock timing.

JP 2011-208509 A JP 2011-89463 A

  By the way, in an apparatus provided with an intake valve timing changing mechanism for changing the valve timing of the intake valve and an exhaust valve timing changing mechanism for changing the valve timing of the exhaust valve, the cam rotor and the cam sensor are connected to the intake cam shaft and Provided on each exhaust camshaft.

  In an apparatus in which the valve timing changing mechanism is provided with a lock mechanism, it is desirable that the cam angle detection accuracy be high in order to appropriately perform locking and unlocking by the lock mechanism. Based on this point, the intake cam angle detection accuracy is the exhaust cam angle detection accuracy in a device in which the lock mechanism is provided only in the intake valve timing change mechanism and the exhaust valve timing change mechanism. It is conceivable to set a higher value. In order to increase the estimation accuracy of the crank angle when the crank sensor is abnormal in such a device, it is desirable to use an intake cam sensor detection signal (intake cam signal) for estimation of the crank angle.

  In an internal combustion engine equipped with an intake valve timing change mechanism, when the intake valve timing changes, the relationship between the crank angle and the intake cam angle also changes, so the crank angle based only on the intake cam signal when the crank sensor is abnormal is changed. It is difficult to properly perform estimation, and it is also difficult to execute engine control based on the crank angle.

  In order to fix the intake valve timing, the fluid supply to the advance pressure chamber is continued and the intake valve timing is set to the most advanced position, or the fluid supply to the retard pressure chamber is continued and the intake valve timing is set to the most retarded position. However, in this case, there is a high possibility that the engine operating state will be deteriorated.

  In order to suppress such deterioration of the engine operating state, it is conceivable to lock the intake valve timing at the lock timing by a lock mechanism. However, since an appropriate signal cannot be detected as a crank signal when the crank sensor is abnormal, the intake cam angle detection that is executed based on the relationship between the crank signal and the intake cam signal is appropriately executed. It is difficult. Therefore, it is difficult to change the intake valve timing to the lock timing through the operation control of the intake valve timing change mechanism, and it is difficult to accurately execute the lock of the valve timing at the lock timing by the lock mechanism.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine that can appropriately perform estimation of a crank angle when the crank sensor is abnormal and execution of engine control based on the crank angle. It is to provide a control device.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to a first aspect of the present invention, there is provided an intake valve timing changing mechanism for changing an intake valve timing through a change in a rotation phase of an intake camshaft with respect to a crankshaft of an internal combustion engine, and a change in a rotation phase of an exhaust camshaft with respect to the crankshaft. An exhaust valve timing changing mechanism for changing the exhaust valve timing, a first rotating body coupled to the crankshaft when the intake valve timing is a lock timing intermediate between the most retarded angle timing and the most advanced angle timing; A lock mechanism that mechanically engages a second rotating body coupled to the intake camshaft to lock it, a crank sensor that outputs a crank signal whose output level changes with rotation of the crankshaft, An exhaust cam detection unit that outputs an exhaust cam signal whose output level changes as the exhaust cam shaft rotates, and the exhaust cam detection unit An intake cam detection unit that outputs an intake cam signal that has a higher detection accuracy and changes an output level as the intake camshaft rotates, and rotates the crankshaft based on the crank signal and the cam signal. In a control device for an internal combustion engine that detects an angle and executes engine control based on the rotation angle, the device is based on the exhaust cam signal to lock the lock mechanism when the crank sensor is abnormal. The gist of the invention is to execute the operation control of the intake valve timing changing mechanism, estimate the rotation angle of the crankshaft based on the intake cam signal, and execute the engine control based on the rotation angle.

  According to the above device, the mechanical engagement by the lock mechanism between the first rotating body connected to the crankshaft and the second rotating body connected to the intake camshaft (unlocked state), that is, When any abnormality occurs in the crank sensor in a state where the change of the intake valve timing is permitted, the relative relationship between the first rotating body and the second rotating body is controlled through the operation control of the intake valve timing changing mechanism based on the exhaust cam signal. The locked state in which the rotation is restricted can be set. In such a state, that is, in a state in which the relative rotation between the crankshaft and the intake camshaft is locked, the crank is determined based on the detection signal (intake cam signal) of the intake cam detection unit with higher detection accuracy than the exhaust cam detection unit. Since the rotation angle (crank angle) of the shaft can be estimated, the estimation of the crank angle can be performed with high accuracy. Therefore, the operation control of the internal combustion engine can be properly executed based on the estimated crank angle.

  According to a second aspect of the present invention, there is provided the internal combustion engine control apparatus according to the first aspect, wherein the exhaust valve timing changing mechanism is configured to advance the exhaust valve timing when the crank sensor is abnormal. The intake valve timing change mechanism in an execution mode in which the intake valve timing is estimated based on the exhaust cam signal and the intake cam signal, and the estimated intake valve timing and the lock timing are matched. The main point is to execute the operation control.

  According to the above apparatus, when the abnormality occurs in the crank sensor, the exhaust valve timing is changed to the most advanced angle timing by executing the operation control of the exhaust valve timing changing mechanism in the execution mode in which the exhaust valve timing is advanced. And at the same most retarded angle. Then, by using the exhaust cam signal output from the exhaust cam detection unit as a reference timing signal in such a state, that is, in a state where the relative rotation between the crankshaft and the exhaust camshaft is stopped, It is possible to estimate the intake valve timing based on the relationship. Therefore, the actual intake valve timing can be changed to the lock timing by executing the operation control of the intake valve timing changing mechanism in an execution mode in which the estimated intake valve timing and the lock timing are matched. Can be locked.

According to the second aspect of the present invention, the operation control of the intake valve timing changing mechanism based on the exhaust cam signal can be executed so that the lock mechanism is brought into the locked state in this way.
According to a third aspect of the present invention, there is provided the control apparatus for an internal combustion engine according to the second aspect, wherein the intake valve timing changing mechanism is configured such that the second rotating body is integrally attached to the intake camshaft. The first rotating body is a housing in which the vane is accommodated, and the interior is a pressure chamber for an advance angle behind the rotation direction by the vane. And a housing that is partitioned into a retarding pressure chamber on the front side in the rotation direction, and the vane passes through the interior of the housing through supply and discharge of pressurized fluid to and from the advance pressure chamber and the retarding pressure chamber. The first rotating body and the second rotating body are rotated relative to each other by moving the first rotating body, and the lock mechanism is provided so as to be able to appear and retract on one of the first rotating body and the second rotating body. The first rotating body and the second rotating body are mechanically engaged with each other through engagement between a hook pin and a recess formed on the other side, and the control device performs the estimation when the crank sensor is abnormal. The gist of the invention is to perform the operation control of the lock mechanism in an execution mode in which the lock pin protrudes when the intake valve timing and the lock timing coincide with each other.

  According to the above-described device, the lock pin can be protruded to bring the lock mechanism into the locked state at the timing when the intake valve timing is expected to be the lock time. Therefore, it is possible to appropriately perform the engagement between the lock pin and the recess, and thus the restriction at the lock timing of the intake valve timing.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the second rotating body is integrally attached to the intake camshaft and extends in a radial direction of the intake camshaft. The first rotating body is a housing in which the vane is housed, and the interior is advanced by the vane with respect to the advance pressure chamber on the rear side in the rotation direction and the retard angle on the front side in the rotation direction. The intake valve timing changing mechanism is configured to supply the vane to the housing through the supply and discharge of pressurized fluid to and from the advance pressure chamber and the retard pressure chamber. When the crank sensor is abnormal, the advance pressure chamber and the retard pressure chamber temporarily move when the first rotary body and the second rotary body rotate relative to each other. Communication In addition, a small amount of fluid is supplied to the advance pressure chamber and a small amount of fluid is discharged from the retard pressure chamber, and the lock mechanism includes the first rotating body and the second rotating body. The first rotating body and the second rotating body are mechanically engaged with each other through engagement of a lock pin provided on one side of the lock pin and a recess formed on the other, and the intake camshaft When the first rotating body and the second rotating body rotate relative to each other based on the alternating torque acting on the rotating body, the lock pin is attached to the plurality of step portions formed in the recess along the rotation direction of the rotating bodies. The control device has a ratchet function that sequentially inserts and gradually advances the intake valve timing to the lock timing, and the control device supplies fluid pressure to the advance pressure chamber and the retard pressure chamber. Generate fluid pressure And an engine driven fluid pressure pump driven by the crankshaft, and when the crank sensor is abnormal, the rotational speed of the crankshaft is estimated based on the exhaust cam signal, and the estimated rotation When the speed is higher than the determination speed, the operation control of the intake valve timing changing mechanism is executed in an execution mode in which the intake valve timing is retarded over a predetermined time, and the lock pin is urged in the protruding direction. The gist of the invention is to execute the operation control of the lock mechanism in the aspect.

  The rotational torque applied to the crankshaft during the operation of the internal combustion engine acts to rotate the intake camshaft relative to the crankshaft relative to the retard side. A state in which the relative rotation between the first rotating body and the second rotating body is allowed by communicating the advance pressure chamber and the retarding pressure chamber by allowing the fluid to move between the pressure chambers. become. Therefore, by temporarily communicating the advance pressure chamber and the retard pressure chamber during the operation of the internal combustion engine, the intake camshaft is relatively rotated to the retard side by the rotational torque, and the intake valve timing is delayed. It changes at the time of the corner. According to the apparatus of claim 4, since the advance pressure chamber and the retard pressure chamber are temporarily communicated when the crank sensor is abnormal, basically, at this time, the intake valve timing is basically set to the lock timing, Alternatively, the timing can be changed to a timing that is retarded from the locking timing, and the locking mechanism can be brought into a locked state by utilizing a ratchet function of the locking mechanism.

  However, in the above apparatus, a small amount of pressurized fluid is supplied to the advance pressure chamber when the advance pressure chamber and the retard pressure chamber communicate with each other when the crank sensor is abnormal, and a small amount is supplied from the retard pressure chamber. The pressurized fluid is discharged. Therefore, if the advance pressure chamber and the retard pressure chamber are simply communicated with each other, when the rotation speed of the crankshaft (engine rotation speed) increases and the pressure of the fluid pumped from the fluid pressure pump increases, There is a possibility that the fluid pressure in the advance pressure chamber becomes high and the intake valve timing is advanced unnecessarily. In this regard, according to the apparatus of the fourth aspect, when the engine rotational speed estimated based on the exhaust cam signal is higher than the determination speed when the crank sensor is abnormal, that is, due to an increase in the fluid pressure in the advance pressure chamber. When there is a possibility of causing an unnecessary advance angle of the intake valve timing, the operation control of the intake valve timing changing mechanism is executed in an execution mode in which the intake valve timing is retarded over a predetermined time. As a result, the intake valve timing can be changed to a timing retarded from the lock timing, and thereafter, the intake valve timing is advanced to the lock timing by using the ratchet function of the lock mechanism to lock the lock mechanism. It becomes possible to be in a state.

According to the fourth aspect of the present invention, the operation control of the intake valve timing changing mechanism based on the exhaust cam signal can be executed so that the lock mechanism is brought into the locked state in this way.
When the temperature of the hydraulic oil changes, the viscosity of the hydraulic oil changes accordingly.Therefore, even if the intake valve timing changing mechanism and the fluid pressure pump are operating in the same operating mode, the advance pressure The oil pressure in the chamber and the oil pressure in the retarding pressure chamber will change. Therefore, when the operation control of the intake valve timing changing mechanism is executed in the execution mode in which the intake valve timing is retarded when the crank sensor is abnormal, the intake valve timing is surely changed from the lock timing to the timing retarded. It can be said that the time required for this depends on the temperature of the hydraulic oil.

  In this regard, in the device according to claim 5, the execution time of the operation control of the intake valve timing changing mechanism in the execution mode in which the intake valve timing is retarded in the predetermined time is the temperature of the hydraulic oil as the fluid. It is variably set accordingly. As a result, when the crank sensor is abnormal, the intake valve timing changing mechanism can be operated efficiently and the intake valve timing can be changed to a timing retarded from the lock timing, so that the lock mechanism can be locked early. it can.

  In addition, as described above, the hydraulic pressure in the advance pressure chamber and the retard pressure chamber change due to the change in the temperature of the hydraulic oil, and therefore the intake valve timing unnecessary advance angle due to the increase in the hydraulic pressure in the advance pressure chamber. The engine speed that causes the engine to change also changes.

  In this regard, in the device according to claim 6, the determination value, that is, a determination value for determining whether or not there is a possibility of causing an unnecessary advance angle of the intake valve timing due to an increase in the fluid pressure of the advance pressure chamber. It is variably set based on the temperature of the hydraulic oil as the fluid. Therefore, there is a possibility that an unnecessary advance angle of the intake valve timing may be caused, in other words, that the operation control of the intake valve timing changing mechanism in the execution mode in which the intake valve timing is retarded must be executed. It can be accurately determined according to the temperature. Therefore, it is possible to efficiently operate the intake valve timing changing mechanism while suppressing unnecessary operation of the intake valve timing changing mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows schematic structure of the control apparatus of the internal combustion engine concerning 1st Embodiment which actualized this invention. 1 is a schematic diagram showing the peripheral structure of a crank sensor, an intake cam sensor, and an exhaust cam sensor. Sectional drawing which shows the cross-section of an intake valve timing change mechanism. FIG. 4 is a cross-sectional view showing a cross-sectional structure taken along line 4-4 of FIG. 3 of the intake valve timing changing mechanism. Sectional drawing which shows an example of the operation | movement aspect of an advance angle locking mechanism. Sectional drawing which shows the other example of the operation | movement aspect of an advance angle locking mechanism. Sectional drawing which shows the other example of the operation | movement aspect of an advance angle locking mechanism. The flowchart which shows the execution procedure of the lock process concerning 1st Embodiment. The flowchart which shows the execution procedure of the lock process concerning 2nd Embodiment which actualized this invention. The flowchart which shows the execution procedure of the lock process concerning other embodiment.

(First embodiment)
Hereinafter, a first embodiment of a control device for an internal combustion engine according to the present invention will be described.
As shown in FIG. 1, a piston 11 is accommodated in a cylinder of the internal combustion engine 10 so as to be able to reciprocate. A combustion chamber 12 is defined by the top surface of the piston 11 and the inner peripheral surface of the cylinder. Connected to the combustion chamber 12 are an intake passage 13 through which air sucked into the combustion chamber 12 passes and an exhaust passage 14 through which combustion gas (exhaust gas) in the combustion chamber 12 is discharged.

  A crankshaft 15 that converts the reciprocating motion into a rotational motion is connected to the piston 11 of the internal combustion engine 10 via a connecting rod 16. An intake camshaft 32 for opening and closing the intake valve 31 and an exhaust camshaft 42 for opening and closing the exhaust valve 41 are provided on the upper portion of the internal combustion engine 10. An intake valve timing changing mechanism 30 for changing the valve timing of the intake valve 31 is attached to the tip of the intake cam shaft 32, and an exhaust valve timing change for changing the valve timing of the exhaust valve 41 is attached to the tip of the exhaust cam shaft. A mechanism 40 is attached.

  In the internal combustion engine 10, the crank sprocket 17 provided on the crankshaft 15, the intake cam sprocket 33 provided on the intake valve timing changing mechanism 30, and the exhaust cam sprocket 43 provided on the exhaust valve timing changing mechanism 40. Drive coupled via a timing chain 18. Thus, when the crankshaft 15 rotates, this rotation is transmitted to the intake cam sprocket 33 and the exhaust cam sprocket 43 via the timing chain 18, and the intake camshaft 32 and the exhaust camshaft 42 rotate.

  The intake valve 31 is always urged in the valve closing direction by an intake valve spring 34. As the intake valve spring 34 is pressed by the intake cam 35 with the rotation of the intake cam shaft 32 and contracts and restores, the intake valve 31 is opened and closed. The exhaust valve 41 is always urged in the valve closing direction by an exhaust valve spring 44. When the exhaust valve spring 44 is pressed and contracted and restored by the exhaust cam 45 as the exhaust cam shaft 42 rotates, the exhaust valve 41 is opened and closed.

  On the other hand, an oil pan 19 that stores hydraulic oil is attached to the lower part of the internal combustion engine 10, and an engine-driven oil pump 20 that is driven by the rotational force of the crankshaft 15 to pump the hydraulic oil in the oil pan 19. Is provided. An oil passage control valve (hereinafter referred to as an intake OCV) 36 that changes the supply / discharge state of the hydraulic oil with respect to each oil chamber of the intake valve timing changing mechanism 30 is provided in the hydraulic oil passage 21 through which hydraulic oil is pumped by the oil pump 20. And an oil passage control valve (hereinafter referred to as exhaust OCV) 46 for changing the supply / discharge state of the hydraulic oil to / from each oil chamber of the exhaust valve timing changing mechanism 40.

  The apparatus of this embodiment is provided with various sensors for detecting the operating state of the internal combustion engine 10. As various sensors, for example, a crank sensor 81 for detecting a rotation angle (crank angle [° CA]) and a rotation speed (engine rotation speed NE) of the crankshaft 15, and a rotation angle (intake cam angle) of the intake camshaft 32. Are provided, and an exhaust cam sensor 83 for detecting the rotation angle (exhaust cam angle) of the exhaust cam shaft 42 is provided. In addition, a water temperature sensor 84 for detecting the temperature THW of the cooling water of the internal combustion engine 10 is also provided. Signals output from these various sensors are taken into an electronic control unit 80 that controls various devices of the internal combustion engine 10 in an integrated manner. The electronic control unit 80 monitors the operating state of the internal combustion engine 10 based on the detection results of various sensors, and controls the operation of the intake OCV 36, the exhaust OCV 46, and the well-known fuel injection control based on the operating state. Various controls are executed.

Hereinafter, the peripheral structure of the crank sensor 81, the intake cam sensor 82, and the exhaust cam sensor 83 will be described separately.
First, the peripheral structure of the crank sensor 81 will be described.

  As shown in FIG. 2, a crank rotor 22 is integrally attached to the crankshaft 15 of the internal combustion engine 10. The crank rotor 22 is formed in a substantially disk shape as a whole, and a plurality (34 in the present embodiment) of the same shape projecting at equal intervals (10 ° CA interval) in the rotation direction on the outer periphery thereof. The part is formed. The crank sensor 81 is provided at a position near the crank rotor 22 and opposed to the outer peripheral surface of the crank rotor 22, and a signal (crank signal) whose output level changes as the crankshaft 15 rotates. Is output. Specifically, as the crank signal, the convex portion of the crank rotor 22 approaches the vicinity so that the output level suddenly increases when the convex portion of the crank rotor 22 approaches and the output level sharply decreases when the convex portion is separated. Each time it passes, a pulsed signal (crank signal) is output.

Next, the peripheral structure of the intake cam sensor 82 will be described.
An intake cam rotor 37 is integrally attached to the intake cam shaft 32 of the internal combustion engine 10. The entire intake cam rotor 37 is formed in a substantially disk shape. On the outer periphery of the intake cam rotor 37, a plurality of protrusions protruding at different protrusion widths and protrusion intervals in the rotation direction are formed. The intake cam sensor 82 is provided at a position near the intake cam rotor 37 and opposed to the outer periphery of the intake cam rotor 37, and outputs an intake cam signal whose output level changes as the intake cam shaft 32 rotates. To do. Specifically, as the intake cam signal, the output level suddenly rises when any of the protrusions of the intake cam rotor 37 approaches as the intake cam shaft 32 rotates, and when any of these protrusions separates. A signal that changes such that the output level suddenly decreases is output. As a result, the intake cam sensor 82 outputs a signal whose output level changes as the intake cam signal when the intake cam angle reaches a preset predetermined angle. In the present embodiment, the intake cam sensor 82 and the intake cam rotor 37 function as an intake cam detection unit.

Next, the peripheral structure of the exhaust cam sensor 83 will be described.
An exhaust cam rotor 47 is integrally attached to the exhaust cam shaft 42 of the internal combustion engine 10. The entire exhaust cam rotor 47 is formed in a substantially disk shape. On the outer periphery of the exhaust cam rotor 47, a plurality of protrusions that protrude with different protrusion widths and protrusion intervals in the rotation direction are formed. The exhaust cam sensor 83 is provided at a position in the vicinity of the exhaust cam rotor 47 and facing the outer periphery of the exhaust cam rotor 47, and an exhaust cam signal whose output level changes as the exhaust cam shaft 42 rotates is provided. Output. Specifically, as the exhaust cam signal, a signal whose output level rapidly increases when any of the projections of the exhaust cam rotor 47 approaches as the exhaust cam shaft 42 rotates is output. As a result, the exhaust cam sensor 83 outputs a signal whose output level changes as the exhaust cam signal when the exhaust cam angle reaches a predetermined angle. In the present embodiment, the exhaust cam rotor 47 has the same shape as the intake cam rotor 37, and the exhaust cam sensor 83 and the exhaust cam rotor 47 function as an exhaust cam detection unit. The exhaust cam signal output from the exhaust cam detector does not change so that the output level suddenly decreases when any of the protrusions of the exhaust cam rotor 47 is separated from the exhaust cam sensor 83. Therefore, in the apparatus of the present embodiment, the detection accuracy of the intake cam angle by the intake cam detection unit is higher than the detection accuracy of the exhaust cam angle by the exhaust cam detection unit (specifically, the number of detection points). .

  In the apparatus of this embodiment, the crank signal, the intake cam signal, and the exhaust cam signal are taken into the electronic control unit 80. The electronic control unit 80 detects the crank angle and the intake cam angle based on the relationship between the crank signal output level change timing and the intake cam signal output level change pattern, and the crank signal output level change timing and The exhaust cam angle is detected based on the relationship with the change pattern of the exhaust cam signal.

  Hereinafter, the intake valve timing changing mechanism 30 will be described in detail with reference to FIG. Since the intake valve timing changing mechanism 30 and the exhaust valve timing changing mechanism 40 have the same structure, a detailed description of the structure of the exhaust valve timing changing mechanism 40 is omitted.

  As shown in FIG. 3, the intake valve timing changing mechanism 30 includes a housing rotor 51 that rotates in synchronization with the crankshaft 15 (see FIG. 1) and a vane rotor 52 that rotates in synchronization with the intake camshaft 32. Yes. The housing rotor 51 and the vane rotor 52 rotate at the same rotation center. When the valve timing of the intake valve 31 (see FIG. 1) is changed, the relative rotational positions of the housing rotor 51 and the vane rotor 52 are changed.

  The intake cam sprocket 33 is integrally fixed to the housing rotor 51. The housing rotor 51 includes a peripheral wall portion 53 extending in a substantially annular shape, and a partition wall having a shape protruding toward the rotation center (the intake camshaft 32 side) of the housing rotor 51 on the inner surface of the peripheral wall portion 53. Three 54 are formed.

  The vane rotor 52 is fixed to the tip end of the intake camshaft 32 so as to be integrally rotatable, and is disposed inside the housing rotor 51. The vane rotor 52 is integrally formed with three vanes 55 that protrude in a direction away from the rotation axis L1 in the radial direction of the intake camshaft 32. Each of the vanes 55 is disposed at a position sandwiched between two adjacent partition walls 54 of the housing rotor 51. In the present embodiment, the vane rotor 52 and the vane 55 function as a first rotating body, and the housing rotor 51 functions as a second rotating body having a housing in which the vane 55 is accommodated.

  In the intake valve timing changing mechanism 30, a space sandwiched between two adjacent partition walls 54 of the housing rotor 51 and three spaces inside the housing rotor 51 are respectively formed by intake vanes 55 by intake vanes 55. The space is divided into a rear space (advance pressure chamber 56) in the rotation direction X of the shaft 32 and a front space (retard pressure chamber 57) in the rotation direction X. The intake valve timing changing mechanism 30 supplies and discharges pressurized oil as pressurized fluid to and from the advance pressure chamber 56 and the retard pressure chamber 57 through the operation control of the intake OCV 36 to thereby control the intake valve timing. Is changed.

  Specifically, when pressurized oil is supplied to the advance pressure chamber 56 and the pressurized oil is discharged from the retard pressure chamber 57, the advance pressure chamber 56 and the retard pressure chamber 57 are discharged. Accordingly, the vane rotor 52 (specifically, the vane 55) rotates in the rotation direction X (advance side) of the intake camshaft 32 with respect to the housing rotor 51. At this time, the intake valve timing changes to the advance side. When the rotational position of the vane rotor 52 with respect to the housing rotor 51 reaches the frontmost (advanced side) position in the rotational direction X (hereinafter, the most advanced position), the intake valve timing is controlled to be advanced. It becomes the limit (hereinafter, the most advanced time).

  On the other hand, when the pressurized oil is discharged from the advance pressure chamber 56 and the pressurized oil is supplied to the retard pressure chamber 57, the vane rotor 52 rotates with respect to the housing rotor 51 in the direction of rotation of the intake camshaft 32. It turns to the opposite side (retard side) of X. At this time, the intake valve timing changes to the retard side. When the rotational position of the vane rotor 52 with respect to the housing rotor 51 reaches the rearmost (retarded angle) position in the rotational direction X (hereinafter referred to as the most retarded position), the intake valve timing is retarded. It becomes the control limit (hereinafter, the most retarded timing).

  The intake valve timing changing mechanism 30 is provided with a lock mechanism for fixing the intake valve timing at a predetermined timing (lock timing) between the most advanced timing and the most retarded timing. The lock timing is set to an intake valve timing that is different from the most advanced timing and the most retarded timing and is suitable for starting the internal combustion engine 10. In the present embodiment, the lock mechanism is provided only in the intake valve timing changing mechanism 30 and is not provided in the exhaust valve timing changing mechanism 40.

  Specifically, as shown in FIG. 4, the lock mechanism includes two mechanisms, an advance angle lock mechanism 60 and a retard angle lock mechanism 61. Both the advance angle lock mechanism 60 and the retard angle lock mechanism 61 are formed by a lock pin 62A (or 62B) provided so as to be able to appear and retract in the vane 55 of the vane rotor 52 and a recess 63A (or 63B) formed in the housing rotor 51. Through the engagement, the relative rotation between the housing rotor 51 and the vane rotor 52 is restricted. In FIG. 4, of the members having the same function, “A” is added to the end of the reference numeral for the member used for the advance lock mechanism 60, and the end of the reference sign for the member used for the retard lock mechanism 61 Shown with “B” attached. In this embodiment, since the basic structures of the advance lock mechanism 60 and the retard lock mechanism 61 are the same, only the advance lock mechanism 60 will be described below, and a detailed description of the retard lock mechanism 61 will be omitted. .

  One of the three vanes 55 is formed with an accommodation hole 64 </ b> A extending in parallel with the rotation axis L <b> 1 of the intake camshaft 32. The lock pin 62A is housed in a state in which the lock pin 62A can protrude and retract inside the housing hole 64A, and a spring 65A that constantly urges the lock pin 62A in a direction protruding toward the outside of the housing hole 64A (escape direction). Is provided. In addition, a lock release oil chamber 66 capable of supplying and discharging pressurized oil via the intake OCV 36 (see FIG. 2) is formed inside the accommodation hole 64A. When pressurized oil is supplied to the unlocking oil chamber 66, the lock pin 62A moves in the immersion direction against the biasing force of the spring 65A by the biasing force due to the internal pressure, and enters the inside of the accommodation hole 64A. Be contained. On the other hand, when the pressurized oil is discharged from the inside of the unlocking oil chamber 66A, the pressure in the unlocking oil chamber 66A decreases, so that the urging force of the spring 65A moves the lock pin 62A from the accommodation hole 64A. It will be possible to let you.

  In the inner surface of the housing rotor 51, the concave portion 63A extending in an arc shape is formed at a position where the tip of the lock pin 62A of the advance angle locking mechanism 60 faces. The recess 63A includes an upper step portion 67A formed with a relatively shallow depth and a lower step portion 68A formed with a relatively deep depth. The upper step portion 67A is formed in a shape extending on the retard side from the lower step portion 68A.

  The upper pins 67A and 67B and the lower steps 68A and 68B formed in the lock pins 62A and 62B, the recesses 63A and 63B lock the intake valve timing by the alternating torque acting on the intake camshaft 32 when the internal combustion engine 10 is operated. In addition, it has a ratchet function that gradually advances the angle from the retarded side to the lock time. That is, the upper step portions 67A, 67B and the lower step portions 68A, 68B formed in the recesses 63A, 63B are formed when the lock pins 62A, 62B are fitted into the step portions 67A, 67B, 68A, 68B. The displacement of 62B toward the retarded angle is regulated. Further, when the lock pin 62A is fitted into the lower step portion 68A and the lock pin 62B is fitted into the lower step portion 68B, the lock pin 62A is abutted against the inner wall of the lower step portion 68A, thereby restricting the displacement of the lock pin 62A toward the retard side. At the same time, the displacement of the lock pin 62B toward the advance side is restricted by abutting against the advance side inner wall of the lower step portion 68B. Thereby, the intake valve timing is locked at the lock timing.

Hereinafter, the ratchet function of the lock mechanism will be described in detail.
Specifically, the alternating torque is a torque generated by the urging force of the intake valve spring 34 (see FIG. 1). When the intake valve spring 34 is compressed when the intake valve 31 is opened, the intake camshaft 32 is delayed. While the intake valve spring 34 is extended when the intake valve 31 is closed, the intake cam shaft 32 is relatively rotated to the advance side. When the alternating cam torque causes the intake camshaft 32 (specifically, the vane rotor 52) to swing such that the relative rotation toward the advance side and the relative rotation toward the retard side are alternately repeated, The intake valve timing is advanced using the motion.

  For example, when a torque that relatively rotates the intake camshaft 32 toward the advance side when the intake valve timing is at the most retarded angle acts on the intake camshaft 32, the rotational speed of the vane rotor 52 that is drivingly connected to the intake camshaft 32 Temporarily exceeds the rotational speed of the housing rotor 51 that is drivingly connected to the crankshaft 15. As a result, the vane rotor 52 rotates relative to the housing rotor 51 in the advance angle direction, the lock pins 62A and 62B are displaced toward the advance angle side, and the lock pin 62B is fitted into the upper step portion 67B of the recess 63B.

  In this state, when torque that relatively rotates the intake camshaft 32 to the retard side acts on the intake camshaft 32, the housing rotor 51 and the vane rotor 52 tend to rotate relative to each other in the direction in which the intake valve timing is retarded. However, at this time, since the lock pin 62B hits the inner wall of the upper step portion 67B on the retard side, the relative rotation between the housing rotor 51 and the vane rotor 52 in the direction in which the intake valve timing is retarded is restricted. As a result, the retard of the intake valve timing is regulated at a timing that is more advanced than the most retarded timing.

  In this state, the lock pin 62A is inserted into the upper step portion 67A of the recess 63A by the alternating torque further acting on the intake camshaft 32, and then the lock pin 62B is inserted into the lower step portion 68B of the recess 63B. Then, the lock pin 62A is fitted into the lower step portion 68A of the recess 63A. As a result, the retard of the intake valve timing is regulated in stages from the retard side timing to the lock timing, and the intake valve timing shifts to a locked state at the lock timing.

  Further, as shown in FIG. 5, an outer pin 71 </ b> A is accommodated in the accommodation hole 64 </ b> A formed in the vane 55 in addition to the lock pin 62 </ b> A. Specifically, an outer pin 71A formed in an annular shape is extrapolated to a lock pin 62A formed in a cylindrical shape so as to be slidable in the axial direction (vertical direction in the drawing).

  On the outer peripheral surface of the lock pin 62A, a flange portion 72A having a shape protruding outward is formed over the entire periphery. When the lock pin 62A moves toward the concave portion 63A (lower side in the figure) by the urging force of the spring 65A, the flange portion 72A engages with the inner surface of the outer pin 71A, and the lock pin 62A also returns to the outer pin 71A. To move. Also, when the outer pin 71A moves in a direction away from the recess 63A (upward in the figure), since the flange portion 72A engages with the inner surface of the outer pin 71A, the lock pin 62A also moves with the outer pin 71A. It becomes like this.

  An outer pin spring 73A that constantly urges the outer pin 71A toward the lower side in the figure is disposed inside the accommodation hole 64A. In addition, the lock release oil chamber 66A is partitioned and formed in the storage hole 64A by the inner surface of the storage hole 64A, the outer peripheral surface of the lock pin 62A, and the outer surface of the outer pin 71A on the concave portion 63A side. An unlocking oil passage 69A is connected to the unlocking oil chamber 66A. Then, when pressurized oil is supplied into the unlocking oil chamber 66A through the unlocking oil passage 69A, the outer pin 71A and the lock pin 62A both resist the urging force of the outer pin spring 73A and the spring 65A in the figure. Moves upward.

  In addition, an oil chamber communication path 74A that communicates with the retard pressure chamber 57 and an oil chamber communication path 75A that communicates with the advance pressure chamber 56 are connected to the accommodation hole 64A. These oil chamber communication passages 74A and 75A are communicated with each other through the accommodation hole 64A when the outer pin 71A moves downward in the figure, and when the outer pin 71A moves upward in the figure, the mutual communication by the outer pin 71A. It is designed to be blocked. Therefore, when the pressure in the unlocking oil chamber 66A decreases and the outer pin 71 moves downward in the figure, the retard pressure chamber 57 and the advance pressure chamber 56 are communicated with each other.

The advance lock mechanism 60 and the retard lock mechanism 61 basically operate as follows through the operation control of the intake OCV 36.
After the start-up of the internal combustion engine 10 is completed, pressurized oil is supplied to the unlocking oil chamber 66 and the lock pin 62 escapes from the recess 63 in each of the lock mechanisms 60 and 61 (the unlocked state [FIG. 5 The state shown in FIG. At this time, the communication between the advance pressure chamber 56 and the retard pressure chamber 57 through the accommodation hole 64 is blocked by the outer pin 71. Therefore, at this time, the intake valve timing can be changed through supply / discharge of pressurized oil to / from the advance pressure chamber 56 and the retard pressure chamber 57.

  On the other hand, when the operation of the internal combustion engine 10 is stopped, the lock timing is set as the control target value of the intake valve timing, and the actual intake valve timing (specifically, the intake cam angle detected by the intake cam detection unit) is set. And the operation state of the intake OCV 36 are feedback-controlled so that the lock timing coincides with the lock timing. When the actual intake valve timing coincides with the lock timing, the operation control of the intake OCV 36 is executed in an execution mode in which the pressurized oil is discharged from the lock release oil chamber 66. As a result, the lock pin 62 of each lock mechanism 60, 61 is urged toward the recess 63 while the intake valve timing is at the lock timing. Therefore, the lock pin 62 of each lock mechanism 60, 61 is inserted into the recess 63 and engaged (locked state [state shown in FIG. 6]). Therefore, when the internal combustion engine 10 is subsequently started, the intake valve timing is fixed at the lock timing, so that the internal combustion engine 10 is started properly.

  In the apparatus of the present embodiment, the operation of the lock mechanisms 60 and 61 when the operation of the internal combustion engine 10 is stopped may fail and the lock pin 62 may remain in the state where it is removed from the recess 63. Even in such a case, when the internal combustion engine 10 is started thereafter, the pressures in the advance pressure chamber 56 and the retard pressure chamber 57 are very low, that is, relative to the housing rotor 51 and the vane rotor 52. The alternating torque is applied to the vane rotor 52 in a state where the rotation is allowed. Therefore, the vane rotor 52 swings by alternating torque such that the relative rotation to the advance side and the relative rotation to the retard side are repeated alternately. Therefore, by the ratchet function of the lock mechanism described above, the intake valve timing gradually changes to the lock time and is locked at the lock time.

  At this time, if the pressurized oil is hardly discharged from the advance pressure chamber 56 or the retard pressure chamber 57, the advance pressure chamber 56 is accompanied by the oscillation of the vane rotor 52 by the alternating torque. In other words, the internal pressure of the retarding pressure chamber 57 decreases or increases. The pressure increase in the advance pressure chamber 56 and the pressure decrease in the retard pressure chamber 57 contribute to limiting the relative rotation of the vane rotor 52 toward the retard side. The increase in the pressure in the retarding pressure chamber 57 contributes to limiting the relative rotation of the vane rotor 52 toward the advance side. Therefore, it can be said that fluctuations in the internal pressure of the advance pressure chamber 56 and the retard pressure chamber 57 due to the oscillation of the vane rotor 52 are one factor that limits the early change in the relative rotational position of the vane rotor 52.

  In the apparatus of this embodiment, when the internal combustion engine 10 is started, the advance pressure chamber 56 and the retard pressure chamber 57 are temporarily communicated through the oil chamber communication passages 74 and 75 formed in the vane 55. It will be in the state. Specifically, as shown in FIG. 7, since the pressurized oil is not supplied to the unlocking oil chamber 66 at this time, the outer pin 71 is moved to the recess 63 side (lower side in the figure) by the urging force of the outer pin spring 73. Thus, the advance pressure chamber 56 and the retard pressure chamber 57 communicate with each other through the oil chamber communication passages 74 and 75 and the accommodation hole 64. Therefore, when the vane rotor 52 is swung by the alternating torque described above, oil and air can be discharged from the retard pressure chamber 57 to the advance pressure chamber 56 when the vane rotor 52 rotates relative to the advance angle. When the vane rotor 52 rotates relative to the retard side, oil and air can be discharged from the advance pressure chamber 56 to the retard pressure chamber 57. As a result, an increase or decrease in the internal pressure of the advance pressure chamber 56 or the retard pressure chamber 57 can be suppressed, so that the swing width of the vane rotor 52 due to the alternating torque can be increased, and the intake valve timing can be increased. Thus, the relative rotational position of the vane rotor 52 can be quickly changed to the position where the position becomes the lock position. In the apparatus of this embodiment, when the advance pressure chamber 56 and the retard pressure chamber 57 are communicated with each other in this way, they operate inside the advance pressure chamber 56 and the retard pressure chamber 57. In order to make the oil filled, a small amount of hydraulic oil is supplied to the advance pressure chamber 56 and a small amount of hydraulic oil is discharged from the retard pressure chamber 57. The amount of hydraulic oil supplied to the advance pressure chamber 56 and the amount of hydraulic oil discharged from the retard pressure chamber 57 at this time is a very small amount that is unlikely to rotate the vane rotor 52 relative to the housing rotor 51. Is set.

  In the apparatus according to the present embodiment, if any abnormality occurs in the crank sensor 81, the crank angle cannot be detected, so that it is difficult to properly control the operation of the internal combustion engine 10. Therefore, when the crank sensor 81 is abnormal, as a fail-safe control, the crank angle is estimated based only on the cam signal without using the crank signal and used for engine control.

  Here, in the apparatus of the present embodiment, as described above, the detection accuracy of the intake cam angle by the intake cam rotor 37 and the intake cam sensor 82 is set higher than the detection accuracy of the exhaust cam angle by the exhaust cam rotor 47 and the exhaust cam sensor 83. Therefore, in order to increase the estimation accuracy of the crank angle when the crank sensor 81 is abnormal, it is desirable to use the detection signal (intake cam signal) of the intake cam sensor 82 for estimation of the crank angle.

  In a situation where the lock mechanism is not locked and the intake valve timing changes, the relationship between the crank angle and the intake cam angle also changes. Therefore, the crank angle based only on the intake cam signal when the crank sensor 81 is abnormal. It is difficult to properly estimate The supply of hydraulic oil to the advance angle pressure chamber 56 is continued to hold the intake valve timing at the most advanced position, or the supply of hydraulic oil to the retard pressure chamber 57 is continued to set the intake valve timing to the most retarded position. However, in this case, there is a high possibility that the operating state of the internal combustion engine 10 is deteriorated.

  By setting the lock mechanism to the locked state, it is possible to fix the intake valve timing while suppressing the deterioration of the operating state of the internal combustion engine 10. However, since an appropriate signal cannot be detected as a crank signal when the crank sensor 81 is abnormal, the intake cam angle detection that is executed based on the relationship between the crank signal and the intake cam signal is appropriately executed. It is difficult. Therefore, it is difficult to change the intake valve timing to the lock timing through the operation control of the intake OCV 36, and it is also difficult to accurately execute the lock of the intake valve timing at the lock timing by the lock mechanism.

  In view of this point, in the apparatus according to the present embodiment, when any abnormality occurs in the crank sensor 81, first, the operation control of the intake valve timing changing mechanism 30 based on the exhaust cam signal is executed to bring the lock mechanism into a locked state. . Specifically, the exhaust valve timing changing mechanism 40 (more specifically, the exhaust OCV 46 is used in an operation mode in which hydraulic oil is supplied to the advance pressure chamber of the exhaust valve timing change mechanism 40 and the hydraulic oil is discharged from the retard pressure chamber. ) Is controlled. Thereby, since the operation control of the exhaust valve timing changing mechanism 40 is executed in an execution mode in which the exhaust valve timing is advanced, the exhaust valve timing can be changed to the most advanced timing and held at the same most retarded timing. it can.

  Thereafter, an estimated value of the intake valve timing (estimated intake cam angle) is calculated based on the relationship between the exhaust cam signal and the intake cam signal, and the intake valve is set so that the estimated intake cam angle matches the lock timing. The operation state of the timing changing mechanism 30 (specifically, the intake OCV 36) is feedback-controlled. When the exhaust valve timing is maintained at the most advanced angle timing, the relationship between the crank angle and the exhaust cam angle does not change, so the exhaust cam signal detected by the exhaust cam sensor 83 is used as a reference timing signal. The intake valve timing (intake cam angle) can be estimated based on the relationship between the exhaust cam signal and the intake cam signal. In the apparatus of the present embodiment, the operation control of the intake valve timing changing mechanism 30 is executed in an execution mode in which the intake cam angle estimated as described above (the estimated intake cam angle) matches the lock timing. The intake cam angle can be changed to the lock time.

  When the estimated intake cam angle coincides with the lock timing, the pressurized oil is discharged from the lock release oil chamber 66 of the lock mechanisms 60 and 61. Thereby, the lock pin 62 can be protruded so that the lock mechanisms 60 and 61 are locked at a timing when the intake valve timing is expected to be the lock timing. Therefore, the engagement between the lock pin 62 and the recess 63, and thus the restriction at the lock timing of the intake valve timing can be appropriately performed.

  In the apparatus according to the present embodiment, after the lock mechanisms 60 and 61 are locked in this manner, an estimated value (estimated crank angle) of the crank angle is calculated based on the intake cam signal, and based on the estimated crank angle. Thus, the operation control of the internal combustion engine 10 is executed.

Hereinafter, the operation of the apparatus of the present embodiment will be described.
In the apparatus of the present embodiment, when any abnormality occurs in the crank sensor 81 in a situation where the lock mechanisms 60 and 61 are in the unlocked state, that is, a situation where the change of the intake valve timing is permitted, first, the exhaust cam The lock mechanisms 60 and 61 are brought into the locked state through the operation control of the intake OCV 36 based on the signal. In such a state, that is, in a state where the relative rotation between the crankshaft 15 and the intake camshaft 32 is locked, it is based on a detection signal (intake cam signal) of the intake cam detection unit with higher detection accuracy than the exhaust cam detection unit. The crank angle is estimated. Thereby, since estimation of a crank angle can be performed with high precision, the operation control of the internal combustion engine 10 can be appropriately performed based on the estimated crank angle.

Hereinafter, a process for locking the lock mechanism when the crank sensor 81 is abnormal (lock process) will be described in detail.
FIG. 8 shows an execution procedure of the lock process. The series of processes shown in the flowchart of FIG. 8 is executed by the electronic control unit 80 as an interrupt process at predetermined intervals.

  As shown in FIG. 8, in this process, it is first determined whether or not an abnormality has occurred in the crank sensor 81 (step S101). If no abnormality has occurred in the crank sensor 81 (step S101: NO), this processing is temporarily terminated without executing the following processing.

  Thereafter, when it is determined that some abnormality has occurred in the crank sensor 81 by repeatedly executing this processing (step S101: YES), the operation of the exhaust valve timing changing mechanism 40 in the execution mode in which the exhaust valve timing is advanced. Execution of control is started (step S102). Specifically, the operation of the exhaust OCV 46 is controlled in an operation mode in which the hydraulic oil is supplied to the advance pressure chamber of the exhaust valve timing changing mechanism 40 and the hydraulic oil is discharged from the retard pressure chamber.

  Thereafter, it is determined whether or not the change speed of the exhaust valve timing (specifically, the exhaust cam angle) is equal to or lower than a predetermined speed (specifically, substantially “0”) (step S103). When the change speed of the exhaust cam angle is higher than the predetermined speed (step S103: NO), the following processing (step S104 to step S104) is performed assuming that the exhaust cam angle has still changed to the advance side and has not reached the most advanced time. This process is temporarily terminated without executing the process of S107.

  Thereafter, when this process is repeatedly executed and the change speed of the exhaust cam angle becomes equal to or lower than the predetermined speed (step S103: YES), it is determined that the exhaust cam angle is at the most advanced timing, and the exhaust cam signal, the intake cam signal, Based on the relationship, the estimated intake cam angle is calculated (step S104).

  Then, until the estimated intake cam angle and the lock position match (step S105: NO), the operation state of the intake OCV 36 is feedback-controlled so that the estimated intake cam angle and the lock position match.

  Thereafter, when the estimated intake cam angle coincides with the lock position, the pressurized oil is discharged from the inside of the lock release oil chamber 66 of the lock mechanisms 60 and 61 (step S107), and then this process is temporarily ended. As a result, the lock pin 62 is engaged with the recess 63, and the lock mechanisms 60 and 61 are in the locked state.

As described above, according to the present embodiment, the following effects can be obtained.
(1) When the crank sensor 81 is abnormal, the operation control of the intake valve timing changing mechanism 30 based on the exhaust cam signal is executed to set the lock mechanism to the locked state, and the estimated crank angle is calculated based on the intake cam signal. Operation control of the internal combustion engine 10 is executed based on the estimated crank angle. As a result, the crank angle can be estimated based on the detection signal (intake cam signal) of the intake cam detection unit with higher detection accuracy than the exhaust cam detection unit, so that the estimation of the crank angle is performed with high accuracy. Therefore, the operation control of the internal combustion engine 10 can be appropriately executed based on the estimated crank angle.

  (2) When the crank sensor 81 is abnormal, the exhaust valve timing changing mechanism 40 is controlled so that the exhaust valve timing is advanced, so that the exhaust valve timing is changed to the most advanced timing and It can be held at a retarded time. Thereafter, the estimated intake cam angle is calculated based on the relationship between the exhaust cam signal and the intake cam signal, and the operating state of the intake valve timing changing mechanism 30 is fed back so that the estimated intake cam angle matches the lock timing. I tried to control it. Therefore, by using the exhaust cam signal detected by the exhaust cam sensor 83 as a reference timing signal, the estimated intake cam angle can be calculated based on the relationship between the exhaust cam signal and the intake cam signal. Therefore, the actual intake cam angle can be changed to the lock timing by executing the operation control of the intake valve timing changing mechanism 30 in an execution mode in which the estimated intake cam angle and the lock timing are matched.

  (3) When the estimated intake cam angle coincides with the lock timing, the pressurized oil is discharged from the inside of the lock release oil chamber 66 of the lock mechanisms 60 and 61. Therefore, the engagement between the lock pin 62 and the recess 63, and thus the restriction at the lock timing of the intake valve timing can be appropriately performed.

(Second Embodiment)
Hereinafter, a second embodiment that embodies the control device for an internal combustion engine according to the present invention will be described focusing on differences from the first embodiment.

  The apparatus of the present embodiment and the apparatus of the first embodiment differ in the execution mode of the process (lock process) for setting the lock mechanism to the locked state when the crank sensor 81 is abnormal. Hereinafter, the lock processing of this embodiment will be described.

  The rotational torque applied to the crankshaft 15 during the operation of the internal combustion engine 10 acts to relatively rotate the intake camshaft 32 toward the retard side with respect to the crankshaft 15. By connecting the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30, the movement of the hydraulic oil between the pressure chambers 56 and 57 is allowed, thereby allowing the vane rotor 52 and the housing rotor to move. 51 is allowed to rotate relative to 51. Therefore, by temporarily communicating the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 during the operation of the internal combustion engine 10, the intake camshaft 32 is retarded by the rotational torque. It can be said that the intake valve timing changes to the retard side timing by relative rotation to the side. In view of this point, in the apparatus of this embodiment, when the crank sensor 81 is abnormal, the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 are temporarily communicated. Therefore, at this time, the intake valve timing is basically the lock timing or the timing retarded from the lock timing, so the lock mechanisms 60, 61 are locked by using the ratchet function of the lock mechanisms 60, 61, etc. Can be in a state.

  However, in the apparatus of this embodiment, as described above, when the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 are communicated, that is, the hydraulic oil is discharged from the unlocking oil chamber 66. In this case, a small amount of hydraulic oil is supplied to the advance angle pressure chamber 56 and a small amount of hydraulic oil is discharged from the retard pressure chamber 57. Therefore, if the advance pressure chamber 56 and the retard pressure chamber 57 are simply communicated with each other, if the pressure of the hydraulic oil pumped from the oil pump 20 is increased due to an increase in the engine rotational speed NE, the advance angle chamber 56 is used. There is a possibility that the intake valve timing is advanced unnecessarily due to the increase in the hydraulic pressure in the pressure chamber 56.

  In the apparatus of this embodiment, when the crank sensor 81 is abnormal, the engine speed NE is estimated based on the exhaust cam signal. When the estimated engine rotation speed (estimated engine rotation speed) is higher than the determination speed, the intake valve timing changing mechanism 30 (specifically, for intake air) is executed in an execution mode in which the intake valve timing is retarded over a predetermined time. The operation control of OCV 36) is executed. Thereafter, the operation control of the lock mechanisms 60 and 61 (specifically, the intake OCV 36) is executed in an execution mode in which the lock pin 62 is urged in the protruding direction such that the hydraulic oil is discharged from the lock release oil chamber 66. .

In the following, the operation by executing the operation control of the intake OCV 36 will be described.
According to the apparatus of the present embodiment, when the estimated engine rotation speed is higher than the determination speed when the crank sensor 81 is abnormal, that is, an unnecessary advance angle of the intake valve timing due to the increase of the fluid pressure in the advance pressure chamber 56 is obtained. When there is a possibility of inviting, the operation control of the intake OCV 36 is executed in an execution mode in which the intake valve timing is retarded over a predetermined time. As a result, the intake valve timing can be changed to a timing retarded from the lock timing, and thereafter the intake valve timing is advanced to the lock timing by using the ratchet function of the lock mechanisms 60 and 61, and the lock is performed. The mechanisms 60 and 61 can be locked.

  When the estimated engine rotation speed is equal to or lower than the determination speed, the operation control of the intake OCV 36 is executed in an execution mode in which the hydraulic oil is discharged from the lock release oil chamber 66. As a result, the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 are communicated with each other, and a small amount of hydraulic oil is supplied to the advance pressure chamber 56 and the retard pressure chamber. A small amount of hydraulic oil is discharged from 57.

In the apparatus according to the present embodiment, the operation control of the intake valve timing changing mechanism 30 based on the exhaust cam signal is executed so that the lock mechanisms 60 and 61 are locked in this manner.
Here, when the temperature of the hydraulic oil changes, the viscosity of the hydraulic oil also changes accordingly, so that the amount of leakage of the hydraulic oil in the hydraulic oil flow path changes. Therefore, even when the intake valve timing changing mechanism 30 and the oil pump 20 are operating in the same operating mode, the hydraulic pressure of the advance pressure chamber 56 of the intake valve timing changing mechanism 30 according to the temperature of the operating oil. In other words, the hydraulic pressure in the retarding pressure chamber 57 changes. Therefore, when the operation control of the intake valve timing changing mechanism 30 is executed in an execution mode in which the intake valve timing is retarded when the crank sensor 81 is abnormal, the intake valve timing is surely changed from the lock timing to a timing retarded. It can be said that the time required to make it vary depends on the temperature of the hydraulic oil.

  In view of this point, in the apparatus of the present embodiment, the predetermined time, that is, the execution duration of the operation control of the intake valve timing changing mechanism 30 in the execution mode in which the intake valve timing is retarded, is the temperature of the hydraulic oil (in detail, The temperature is variably set according to the coolant temperature THW) as the temperature serving as the index. Specifically, the higher the temperature of the hydraulic oil, the lower the viscosity of the hydraulic oil and the lower the pressure in the retarding pressure chamber 57 and the slower the retarding speed of the intake valve timing. Is set. As a result, when the crank sensor 81 is abnormal, the intake valve timing changing mechanism 30 can be efficiently operated to change the intake valve timing to a timing retarded from the lock timing, so that the lock mechanisms 60 and 61 are locked early. Can be in a state.

  Further, if the hydraulic pressure of the advance pressure chamber 56 or the retard pressure chamber 57 changes due to the temperature change of the hydraulic oil, an unnecessary advance of the intake valve timing due to the increase of the hydraulic pressure of the advance pressure chamber 56 is caused. The engine speed NE to become also changes. In the apparatus according to this embodiment, the determination value, that is, a determination value for determining whether or not there is a possibility of causing an unnecessary advance of the intake valve timing due to an increase in the oil pressure of the advance pressure chamber 56 is the hydraulic oil temperature ( Specifically, it is variably set based on the cooling water temperature THW) as the temperature serving as the index. Specifically, the higher the temperature of the hydraulic oil, the lower the viscosity of the hydraulic oil and the lower the pressure in the advance pressure chamber 56, so that it is less likely to cause an unnecessary advance angle of the intake valve timing. A high speed is set as the determination speed. This may lead to unnecessary advancement of the intake valve timing, in other words, it is necessary to execute the operation control of the intake valve timing changing mechanism 30 in the execution mode in which the intake valve timing is retarded. It can be accurately determined according to the temperature of the oil. Therefore, it is possible to efficiently operate the intake valve timing changing mechanism 30 while suppressing the intake valve timing changing mechanism 30 from operating unnecessarily.

Hereinafter, the lock processing according to the present embodiment will be described in detail.
FIG. 9 shows the execution procedure of the lock process. The series of processes shown in the flowchart of FIG. 8 is executed by the electronic control unit 80 as an interrupt process at predetermined intervals.

  As shown in FIG. 9, in this process, it is first determined whether or not an abnormality has occurred in the crank sensor 81 (step S201). If no abnormality has occurred in the crank sensor 81 (step S201: NO), this processing is temporarily terminated without executing the following processing.

  Then, after this process is repeatedly executed and it is determined that some abnormality has occurred in the crank sensor 81 (step S201: YES), the exhaust valve timing changing mechanism 40 in the execution mode in which the exhaust valve timing is advanced. The operation control is started (step S202). Specifically, the operation of the exhaust OCV 46 is controlled in an operation mode in which the hydraulic oil is supplied to the advance pressure chamber of the exhaust valve timing changing mechanism 40 and the hydraulic oil is discharged from the retard pressure chamber.

  Further, the estimated engine speed is calculated based on the exhaust cam signal (step S203), and the determination speed is calculated based on the coolant temperature THW (step S204). In the process of step S203, the estimated engine rotation speed is calculated based on the change pattern of the output level of the exhaust cam signal and the time interval of each change timing. Moreover, in the apparatus of this embodiment, the relationship between the cooling water temperature THW and the determination speed capable of appropriately locking the lock mechanisms 60 and 61 is obtained in advance based on the results of various experiments and simulations. It is stored in the electronic control unit 80. In the process of step S204, the determination speed is calculated from the above relationship based on the coolant temperature THW.

  If the estimated engine rotational speed is equal to or lower than the determination speed (step S205: YES), it is determined that there is very little possibility of causing an unnecessary advance of the intake valve timing due to the advance of the advance pressure chamber 56, and the lock is released. After the operation control of the intake OCV 36 is executed in the execution mode in which the hydraulic oil is discharged from the oil chamber 66 (step S206), this process is temporarily ended. At this time, the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 are communicated, and a small amount of hydraulic oil is supplied to the advance pressure chamber 56 and the retard pressure chamber 57 is supplied. A small amount of hydraulic fluid is discharged from the tank.

  On the other hand, when the estimated engine rotation speed is higher than the determination speed (step S205: NO), it is assumed that the intake valve timing may be undesirably advanced due to the advance of the advance pressure chamber 56, and the intake air for a predetermined time. The operation control of the intake OCV 36 is executed in an execution mode in which the valve timing is retarded (steps S207 to S209).

  Specifically, first, a predetermined time is calculated based on the coolant temperature THW (step S207). In the apparatus of this embodiment, the relationship between the shortest time (predetermined time) of the time during which the intake valve timing can be surely retarded to the most retarded timing and the coolant temperature THW is various experiments and simulations. Is obtained in advance based on the result of the above and stored in the electronic control unit 80. In the process of step S207, a predetermined time is calculated from the above relationship based on the coolant temperature THW.

  Thereafter, it is determined whether or not the elapsed time after it is determined that some abnormality has occurred in the crank sensor 81 is less than the predetermined time (step S208). The elapsed time is sequentially counted in a process different from the present process and stored in the electronic control unit 80. Then, while the elapsed time is less than the predetermined time (step S208: YES), the operation control of the intake OCV 36 is executed in an execution mode in which the intake valve timing is retarded (step S209). Thereafter, when this process is repeatedly executed and the elapsed time becomes equal to or longer than the predetermined time (step S208: NO), it is determined that the intake valve timing is the most retarded timing, and the unlocking oil chamber 66 of the lock mechanisms 60 and 61 is reached. After the pressurized oil is discharged from the inside (step S206), this process is temporarily terminated. At this time, the advance pressure chamber 56 and the retard pressure chamber 57 are in communication with each other and the lock pins 62A and 62B can project, so that the lock mechanism is operated by the alternating torque acting on the intake camshaft 32. Thus, the intake valve timing is advanced step by step and locked at the lock timing.

As described above, according to the present embodiment, the effects described in the following (4) to (6) can be obtained in addition to the effects described in (1) above.
(4) When the estimated engine rotational speed calculated based on the exhaust cam signal is higher than the determination speed when the crank sensor 81 is abnormal, the operation control of the intake valve timing changing mechanism 30 is performed in an execution mode in which the intake valve timing is retarded over a predetermined time. Was made to run. Moreover, after the predetermined time has elapsed, the operation control of the lock mechanisms 60 and 61 is executed in an execution mode in which the lock pin 62 is urged in the protruding direction. As a result, the intake valve timing can be changed to a timing retarded from the lock timing, and thereafter the intake valve timing is advanced to the lock timing by using the ratchet function of the lock mechanisms 60 and 61, and the lock is performed. The mechanisms 60 and 61 can be locked.

  (5) The predetermined time is variably set according to the cooling water temperature THW. Therefore, when the crank sensor 81 is abnormal, the intake valve timing changing mechanism 30 can be efficiently operated to change the intake valve timing to a timing retarded from the lock timing, so that the lock mechanisms 60 and 61 are locked early. Can be.

  (6) Since the determination speed is variably set based on the coolant temperature THW, the intake valve timing changing mechanism 30 can be efficiently operated while suppressing the intake valve timing changing mechanism 30 from operating unnecessarily. it can.

(Other embodiments)
Each of the above embodiments may be modified as follows.
-The apparatus concerning 1st Embodiment is applicable also to the apparatus provided with the lock mechanism which does not have a ratchet function.

The apparatus according to the first embodiment can also be applied to an apparatus in which the advance pressure chamber 56 and the retard pressure chamber 57 cannot temporarily communicate with each other.
In the first embodiment, the calculation of the estimated intake cam angle is started after the exhaust cam angle reaches the most advanced timing. Instead of this, the calculation of the estimated cam angle may be started at the same time when the exhaust valve timing is changed to the advance timing. Specifically, the process of step S103 of the lock process (FIG. 8) according to the first embodiment may be omitted. According to such an apparatus, it is possible to quickly start both the operation control of the intake valve timing changing mechanism 30 for bringing the lock mechanisms 60 and 61 into the locked state and the operation control of the internal combustion engine 10 based on the estimated crank angle. According to the device that waits for the exhaust cam angle to reach the most advanced timing as in the first embodiment and starts calculating the estimated intake cam angle, the intake air for bringing the lock mechanisms 60 and 61 into the locked state The operation control of the valve timing changing mechanism 30 and the operation control of the internal combustion engine 10 based on the estimated crank angle can be reliably executed under stable conditions.

  -Instead of using the coolant temperature THW, which is a temperature serving as an index of the operating oil temperature, as a setting parameter used for setting the determination speed and the predetermined time in the second embodiment, the operating oil temperature is directly detected. You may make it use.

  As the determination speed in the second embodiment, a higher speed is set as the temperature is higher in a normal region where the temperature of the hydraulic oil is relatively high, and a higher speed is set as the temperature is lower in a low temperature region where the temperature of the hydraulic oil is low May be set. When the temperature of the hydraulic oil is very low, the viscosity of the hydraulic oil becomes extremely high and the pressure loss in the flow path of the hydraulic oil increases, so that the intake valve timing changing mechanism 30 and the oil pump 20 operate in the same operation mode. Even in such a situation, the hydraulic pressure of the advance pressure chamber 56 and the retard pressure chamber 57 of the intake valve timing changing mechanism 30 are lowered. Therefore, it can be said that the lower the operating oil temperature in the low-temperature region, the higher the engine speed NE that causes an unnecessary advance of the intake valve timing due to the increase in the hydraulic pressure of the advance pressure chamber 56. According to the above apparatus, the determination speed in the low temperature region can be set in accordance with such a tendency, so that it is possible to more accurately determine that there is a possibility of causing an unnecessary advance angle of the intake valve timing.

In the second embodiment, a predetermined speed may be set as the determination speed without variably setting the determination speed.
As the predetermined time in the second embodiment, a longer time is set as the temperature is higher in a normal region where the temperature of the hydraulic oil is relatively high, and a longer time is set as the temperature is lower in a low temperature region where the temperature of the hydraulic oil is low. May be set. As described above, when the temperature of the hydraulic oil is extremely low, the advance pressure of the intake valve timing change mechanism 30 is the same even when the intake valve timing change mechanism 30 and the oil pump 20 are operating in the same operation mode. The hydraulic pressure in the chamber 56 and the hydraulic pressure in the retarding pressure chamber 57 are lowered. Therefore, when the operation control of the intake valve timing changing mechanism 30 is executed in the execution mode in which the intake valve timing is retarded when the crank sensor 81 is abnormal, the intake valve timing is reliably changed from the lock timing to the timing on the retard side. It can be said that the time required for this becomes longer as the temperature of the hydraulic oil is lower in the low temperature region. According to the above apparatus, the predetermined time in the low temperature region can be set in accordance with such a tendency, so that the intake valve timing changing mechanism 30 can be operated more efficiently when the crank sensor 81 is abnormal.

In the second embodiment, a predetermined time may be set as the predetermined time without variably setting the predetermined time.
In the second embodiment, the operation control of the intake valve timing changing mechanism 30 in the execution mode in which the intake valve timing is retarded and the operation control of the lock mechanisms 60 and 61 in the execution mode in which the lock pin 62 is biased in the protruding direction. May be executed simultaneously. Such a device is realized by adopting a structure in which the intake valve timing changing mechanism 30 and the lock mechanisms 60 and 61 are driven by different actuators.

  When the estimated engine speed is determined to be equal to or lower than the determination speed in the lock process (FIG. 9) according to the second embodiment (step S205: YES), the lock process (FIG. 8) according to the first embodiment is performed. You may make it perform the process of step S105-step S107. FIG. 10 shows an execution procedure of such lock processing.

  In each embodiment, the valve timing changing mechanism includes a housing rotor 51 connected to the crankshaft 15 and a vane rotor 52 that is housed in the housing rotor 51 so as to be relatively rotatable and fixed to the camshaft. However, the invention is not limited to this, and other configurations may be adopted.

  In each embodiment, the valve timing changing mechanism and the lock mechanism may be driven by a fluid other than hydraulic oil (for example, cooling water or compressed air). The lock mechanism may be any mechanism that restricts the valve timing to a predetermined phase by mechanical engagement, and is not limited to a mechanism in which a lock pin is inserted into the recess.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Piston, 12 ... Combustion chamber, 13 ... Intake passage, 14 ... Exhaust passage, 15 ... Crankshaft, 16 ... Connecting rod, 17 ... Crank sprocket, 18 ... Timing chain, 19 ... Oil pan, 20 DESCRIPTION OF SYMBOLS ... Oil pump, 21 ... Hydraulic oil passage, 22 ... Crank rotor, 30 ... Intake valve timing change mechanism, 31 ... Intake valve, 32 ... Intake cam shaft, 33 ... Intake cam sprocket, 34 ... Intake valve spring, 35 ... Intake 36 ... OCV for intake, 37 ... Intake cam rotor, 40 ... Intake valve timing changing mechanism, 41 ... Exhaust valve, 42 ... Exhaust cam shaft, 43 ... Exhaust cam sprocket, 44 ... Exhaust valve spring, 45 ... For exhaust Cam, 46 ... OCV for exhaust, 47 ... Exhaust cam rotor, 51 ... Housing rotor, 52 ... , 53 ... peripheral wall, 54 ... partition wall, 55 ... vane, 56 ... advance angle pressure chamber, 57 ... retard angle pressure chamber, 60 ... advance angle lock mechanism, 61 ... retard angle lock mechanism, 62, 62A, 62B ... Lock pin, 63, 63A, 63B ... Recess, 64, 64A, 64B ... Housing hole, 65, 65A, 65B ... Spring, 66 ... Unlock oil chamber, 67, 67A, 67B ... Upper step, 68, 68A, 68B ... Lower stage part, 69, 69A, 69B ... Unlocking oil passage, 71, 71A, 71B ... Outer pin, 72, 72A, 72B ... Flange part, 73, 73A, 73B ... Outer pin spring, 74, 74A, 74B, 75, 75A, 75B ... oil chamber communication path, 80 ... electronic control unit, 81 ... crank sensor, 82 ... intake cam sensor, 83 ... exhaust cam sensor, 84 ... water temperature sensor.

Claims (6)

Intake valve timing changing mechanism for changing intake valve timing through change of rotation phase of intake camshaft with respect to crankshaft of internal combustion engine, and exhaust valve timing for changing exhaust valve timing through change of rotation phase of exhaust camshaft with respect to crankshaft A change mechanism, and a first rotating body coupled to the crankshaft and a second coupling coupled to the intake camshaft when the intake valve timing is a lock timing intermediate between the most retarded angle timing and the most advanced angle timing. A lock mechanism that mechanically engages the rotating body to lock the crank, a crank sensor that outputs a crank signal whose output level changes as the crankshaft rotates, and an output level that accompanies the rotation of the exhaust camshaft Exhaust cam detection unit that outputs an exhaust cam signal that changes, and detection accuracy is higher than the exhaust cam detection unit An intake cam detection unit that outputs an intake cam signal whose output level changes with the rotation of the intake camshaft, and detects the rotation angle of the crankshaft based on the crank signal and the cam signal and rotates the same In a control device for an internal combustion engine that executes engine control based on an angle,
The apparatus performs an operation control of the intake valve timing changing mechanism based on the exhaust cam signal to bring the lock mechanism into a locked state when the crank sensor is abnormal, and controls the crankshaft of the crankshaft based on the intake cam signal. An internal combustion engine control apparatus characterized by estimating a rotation angle and executing engine control based on the rotation angle. The control apparatus for an internal combustion engine according to claim 1,
The apparatus performs an operation control of the exhaust valve timing changing mechanism in an execution mode in which the exhaust valve timing is advanced when the crank sensor is abnormal, and an intake valve based on the exhaust cam signal and the intake cam signal. A control apparatus for an internal combustion engine, wherein the control of the intake valve timing changing mechanism is executed in an execution mode in which a timing is estimated and the estimated intake valve timing and the lock timing coincide with each other. The control apparatus for an internal combustion engine according to claim 2,
The intake valve timing changing mechanism includes a vane having a shape in which the second rotator is integrally attached to the intake camshaft and extends in a radial direction of the intake camshaft, and the first rotator is internally A housing in which the vane is accommodated, and the inside is divided into an advance pressure chamber on the rear side in the rotation direction and a retard pressure chamber on the front side in the rotation direction by the vane, The relative rotation of the first rotating body and the second rotating body by moving the vane inside the housing through supply and discharge of pressurized fluid to and from the advance pressure chamber and the retard pressure chamber. And
The locking mechanism includes the first rotating body and the second rotating body through engagement of a lock pin provided in one of the first rotating body and the second rotating body so as to be movable in and out and a recess formed in the other. Are mechanically engaged,
The control device executes the operation control of the lock mechanism in an execution mode in which the lock pin protrudes when the estimated intake valve timing coincides with the lock timing when the crank sensor is abnormal. A control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1,
The second rotating body includes a vane that is integrally attached to the intake camshaft and extends in a radial direction of the intake camshaft.
The first rotating body is a housing in which the vane is accommodated, and the interior is partitioned by the vane into an advance pressure chamber on the rear side in the rotation direction and a retard pressure chamber on the front side in the rotation direction. Having a housing,
The intake valve timing changing mechanism moves the vane within the housing through supply and discharge of pressurized fluid to and from the advance pressure chamber and the retard pressure chamber. The two-rotating body is rotated relative to each other, and when the crank sensor is abnormal, the advance pressure chamber and the retard pressure chamber are temporarily communicated with each other, and the advance pressure chamber has a small amount. And a small amount of fluid is discharged from the retarding pressure chamber,
The locking mechanism includes the first rotating body and the second rotating body through engagement of a lock pin provided in one of the first rotating body and the second rotating body so as to be movable in and out and a recess formed in the other. And when the first and second rotating bodies rotate relative to each other on the basis of the alternating torque acting on the intake camshaft, the rotating bodies move along the rotation direction of the rotating bodies. It has a ratchet function that sequentially inserts the lock pins into a plurality of step portions formed in the recesses to advance the intake valve timing step by step until the lock timing,
The controller is
A fluid pressure pump for generating fluid pressure to be supplied to the advance pressure chamber and the retard pressure chamber, and an engine driven fluid pressure pump driven by the crankshaft,
Execution of estimating the rotational speed of the crankshaft based on the exhaust cam signal when the crank sensor is abnormal, and retarding the intake valve timing for a predetermined time when the estimated rotational speed is higher than a determination speed A control apparatus for an internal combustion engine, characterized in that the operation control of the intake valve timing changing mechanism is executed in a mode and the operation control of the lock mechanism is executed in an execution mode in which the lock pin is biased in a protruding direction. The control apparatus for an internal combustion engine according to claim 4,
The fluid is hydraulic oil;
The control device of the internal combustion engine, wherein the control device variably sets the predetermined time based on the temperature of the hydraulic oil. The control apparatus for an internal combustion engine according to claim 4 or 5,
The fluid is hydraulic oil;
The control device for an internal combustion engine, wherein the control device variably sets the determination speed based on the temperature of the hydraulic oil.