JP2010133272A - Variable cam phase internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable cam phase internal combustion engine facilitating engine startup when a cam phase variable device fails. <P>SOLUTION: When both an ON/OFF solenoid 91 and a linear solenoid 31 are normal, hydraulic fluid in OPA (Oil Pressure Actuated phaser)-side advance chambers 45a, 46a is discharged to a drain passage 94 through hydraulic fluid discharge passages 81-83. When the hydraulic fluid is discharged from the OPA-side advance chambers 45a, 46a, rotational resistance to the retard side of a rotor 23 is reduced. Therefore, since the rotor is pressed in a retard direction by a bias spring 28 when the cranking of the engine E is started, the rotor 23 is rotated to a retard side with respect to a housing 22. When the rotor 23 is relatively rotated to the most retard angle phase with respect to the housing 22, a lock pin 33 pressed by a lock pin spring 34 is fitted into a lock hole 25a, and the rotor 23 and housing 22 are locked in a cam phase in startup. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cam phase variable internal combustion engine provided with a VTC that uses a hydraulic actuator as a drive source, and more particularly to a technique for facilitating engine start and the like when a cam phase variable device fails.

  For gasoline engines, diesel engines, and HCCI (Homogeneous Charge Compression Ignition) engines, intake and exhaust valves are used according to operating conditions to improve output and fuel consumption and reduce harmful exhaust gas components. There are an increasing number of engines (variable valve opening characteristics internal combustion engines) equipped with variable valve gears that change the lift amount and valve opening timing. As a variable valve operating device, there is a conventional variable valve lift control device (hereinafter referred to as VLC) that variably controls the valve lift stepwise or steplessly, and cam phase (valve opening timing). A valve timing control device (Variable Timing Control device: hereinafter referred to as VTC) has also appeared.

As a VLC, there is known one in which a plurality of cams having different valve operating characteristics are formed on a camshaft, and a rocker arm corresponding to each cam is selectively connected to a valve (see Patent Document 1). The VTC includes a hydraulic actuator suitable for high-speed operation (Oil Pressure Actuated phaser: hereinafter referred to as OPA) and a cam torque actuator suitable for low-speed operation (cam torque-driven phase variable mechanism). (Cam Torque Actuated phaser): hereinafter referred to as CTA) and a vane type installed at the end of the camshaft is known (see Patent Document 2). In this type of VTC, it is common to simultaneously switch the hydraulic pressure supply path to the OPA and the hydraulic oil flow direction in the CTA using an oil path switching control mechanism including a spool valve, a linear solenoid, and the like. In an engine equipped with a VTC, if the oil passage switching control mechanism fails (failure occurs) (when a malfunction of the spool occurs due to disconnection of the linear solenoid or biting of foreign matter), the cam phase cannot be controlled. There is a possibility. In view of this, there has been proposed fail-safe control for preventing engine misfire or stall by increasing the fuel injection amount when an abnormality in cam phase control (excessive valve overlap period) is detected (see Patent Document 3). ).
JP 2008-121585 A JP 2002-235513 A Japanese Patent No. 2569999

  However, even if the fail-safe control of Patent Document 3 is adopted, an excessive valve overlap or the like may occur depending on the setting range of the variable range of the cam phase, and a sufficient intake amount cannot be secured even if the fuel injection amount is increased. Misfire may occur. Therefore, not only when the VTC fails while the engine is stopped, but also when the VTC fails during operation, the engine is stalled and cannot be restarted. There was a risk that the driver could remember great anxiety.

  Accordingly, the present inventors have studied a fail-safe mechanism in which the hydraulic pressure supply to the VTC actuator is interrupted by an electromagnetic shut valve or the like and the operation of the CTA is invalidated by a bypass valve at the time of VTC failure. When this fail-safe mechanism is activated, the hydraulic pressure supply is cut off and the OPA also does not function. Therefore, the rotor and the housing are alternately rotated relative to the advance side or the retard side by the cam torque reaction force. For example, if the rotor and the housing are coupled by the lock pin when a predetermined cam phase (hereinafter referred to as a start-up cam phase) is established, it is possible to continue the operation of the engine within a range where no stall occurs. Become. However, even if this fail-safe mechanism is employed, there is a problem that it takes time until the start cam phase is established because the hydraulic oil exists in the OPA, and smooth start cannot be performed.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a variable cam phase internal combustion engine that realizes easy engine start and the like during a failure of the variable cam phase device.

  According to a first aspect of the present invention, there is provided a first rotating member that rotates in synchronization with a crankshaft, a second rotating member that rotates integrally with the camshaft and that is rotatably coupled to the first rotating member, An advance angle side oil chamber and a retard angle side oil chamber are provided between the one rotation member and the second rotation member, and hydraulic oil is supplied to at least one of the advance angle side oil chamber and the retard angle side oil chamber. A hydraulic actuator that changes the cam phase by being supplied; a supply switching means that is used for supply switching control of hydraulic oil to the advance side oil chamber and the retard side oil chamber; and A cam phase variable internal combustion engine equipped with a cam phase variable device having a hydraulic oil supply / discharge means for hydraulic oil supply / discharge control, wherein the advance side oil chamber, the retard side oil chamber, Any one of the above and the hydraulic oil supply / discharge means via the supply switching means. Hydraulic fluid discharge path to be communicated without failure, failure determination means for determining a failure related to the cam phase variable device, and when the failure is determined by the failure determination means, the supply switching means to the hydraulic oil And a failure drive means for discharging the hydraulic oil by the supply / discharge means.

  According to a second aspect of the present invention, in the cam phase variable internal combustion engine according to the first aspect of the invention, the cam torque acting on the camshaft is used as a driving force, and the relative angle between the first rotating member and the second rotating member is set. A cam torque actuator to be changed or held; and a disabling means for disabling the operation of the cam torque actuator; and the failure-time drive means, when the failure is determined by the failure determination means, The invalidating means is also activated.

According to a third aspect of the present invention, in the cam phase variable internal combustion engine according to the first or second aspect of the invention, the cam phase is fixed so that the first rotating member and the second rotating member are coupled at a predetermined starting cam phase. The failure drive means further operates the cam phase fixing means when the failure is determined by the failure determination means.
A cam phase variable internal combustion engine according to claim 1 or 2.

  According to a fourth aspect of the present invention, in the variable cam phase internal combustion engine according to the first to third aspects of the present invention, the cam phase variable type internal combustion engine is interposed between the first rotating member and the second rotating member, The apparatus further comprises a biasing means for biasing the second rotating member toward the start cam phase.

  According to the first aspect of the invention, when the failure determining means determines the failure of the cam phase varying device, the hydraulic oil supply / discharge means is driven to the hydraulic oil discharge side by the failure driving means, and the advance side oil chamber (or , The hydraulic oil in the retard side oil chamber) is discharged via the hydraulic oil discharge passage and the hydraulic oil supply / discharge means. As a result, the first rotating member and the second rotating member can easily rotate relative to the retard side (or advance side), and the cam phase at the start can be quickly established. According to the second aspect of the invention, since the operation of the cam torque actuator is invalidated, the start-up cam phase is smoothly established regardless of the operating state of the oil passage switching control mechanism. According to the third aspect of the invention, since the first rotating member and the second rotating member are fixed when the starting cam phase is reached, unnecessary operations after the starting cam phase is established do not occur. According to the fourth aspect of the invention, the establishment of the starting cam phase is performed more quickly.

Hereinafter, an embodiment of a cam phase variable internal combustion engine according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view of a main part of an automobile engine according to the embodiment, FIG. 2 is an exploded perspective view of the VTC actuator according to the embodiment, and FIG. 3 is a schematic configuration diagram of the VTC actuator according to the embodiment. . FIG. 4 is a cross-sectional view showing an operation mode of the bypass valve according to the embodiment, and FIG. 5 is a cross-sectional view showing an operation mode of the electromagnetic shut valve according to the embodiment. FIG. 6 is a block diagram showing a schematic configuration of the engine ECU according to the embodiment.

<< Configuration of Embodiment >>
<Overall configuration>
An engine E (cam phase variable internal combustion engine) shown in FIG. 1 is a DOHC 4-valve four-cycle in-line four-cylinder gasoline engine mounted on an automobile. An intake valve 2 for each cylinder is provided in the cylinder head 1. And an exhaust valve 3, an intake camshaft 4 and an exhaust camshaft 5 that drive the intake and exhaust valves 2 and 3. Both camshafts 4 and 5 are rotationally driven at a rotational speed ½ that of the crankshaft 10 via the crank sprocket 6, the cam chain 7, the intake cam sprocket 8, and the exhaust cam sprocket 9. The crankshaft 10 is connected to the piston 12 via a connecting rod 11 and drives an oil pump 14 installed obliquely downward via a chain 13.

  The cylinder head 1 and the cylinder block 15 are formed with a hydraulic oil supply oil passage 16 for supplying hydraulic oil (engine oil) from the oil pump 14 to the VTC actuators 20 and 21 described later. The cylinder head 1 is provided with a normally open type electromagnetic shut valve 17, and when the electromagnetic shut valve 17 is operated, the supply form of hydraulic oil to the VTC actuators 20 and 21 is switched. An intake side cam angle sensor 18 is installed at the rear end of the intake camshaft 4, and an exhaust side cam angle sensor 19 is installed at the rear end of the exhaust camshaft 5.

  An intake side VTC actuator 20 is attached to the front end of the intake camshaft 4, and an exhaust side VTC actuator 21 is attached to the front end of the exhaust camshaft 5. An intake side VLC mechanism 50 is interposed between the intake camshaft 4 and the intake valve 2, and an exhaust side VLC mechanism 51 is interposed between the exhaust camshaft 5 and the exhaust valve 3.

  In the passenger compartment, various controlled devices (electromagnetic shut-off valves) attached to the engine E based on output information of various sensors (both cam angle sensors 18 and 19, an accelerator sensor (not shown), an intake air sensor, a crank angle sensor, etc.) 17, an engine ECU 70 that determines the control amount of both the VTC actuators 20 and 21, both the VLC mechanisms 50 and 51, a fuel injection valve and an ignition coil (not shown), and outputs a drive current is installed.

<VTC actuator>
As shown in FIG. 2, the exhaust-side VTC actuator 21 has a housing 22 having an exhaust cam sprocket 9 formed on the outer periphery thereof, is rotatably held in the housing 22, and a rear end surface is fastened to the front end of the exhaust camshaft 5. The rotor 23, the front plate 24 covering the front surface of the housing 22, the back plate 25 covering the rear surface of the housing 22, the reed valve 26 disposed inside the front plate 24, and the reed valve cover 27 for fixing the reed valve 26 to the rotor 23. The spool valve 29 is driven by being controlled by a bias spring 28 that relatively rotates the housing 22 and the rotor 23 in the retarding direction, a spool valve 29 that is installed at the shaft center of the exhaust camshaft 5 and the rotor 23, and the engine ECU 70. Linear Solenoi 31, a lock pin 33 held by the rotor 23, a lock pin spring 34 for biasing the lock pin 33 toward the back plate 25, a bypass valve 36 held by the rotor 23, and a bypass valve 36 biased toward the front plate 24 The bypass valve spring 37 or the like is a constituent element. The spool valve 29 includes a valve sleeve 38 held at the shaft center of the exhaust camshaft 5 and the rotor 23, a spool 39 slidably fitted in the valve sleeve 38, and the spool 39 attached to the linear solenoid 31 side. And a return spring 40 that is energized.

  As shown in FIG. 3, a first vane 41, a second vane 42, and a third vane 43 are erected on the outer periphery of the rotor 23, while these vanes 41 to 43 are placed at a predetermined angle on the inner periphery of the housing 22. The first to third vane chambers 45 to 47 that are housed so as to be relatively rotatable are formed. In the present embodiment, the first vane 41 and the first vane chamber 45 are components of the first OPA 61, the second vane 42 and the second vane chamber 46 are components of the second OPA 62, and the third vane 43 and the second vane chamber 46. The 3-vane chamber 47 is a component of the CTA 63.

  The first and second vane chambers 45 and 46 are connected to the OPA side advance chambers 45 a and 46 a to which the hydraulic oil from the spool valve 29 is supplied via the OPA side advance oil passages 51 and 52, and from the spool valve 29. First and second vanes 41 and 42 divide into OPA-side retarded chambers 45b and 46b, respectively, through which hydraulic oil is supplied via OPA-side retarded oil passages 53 and 54. The third vane chamber 47 includes a CTA-side advance chamber 47 a that communicates with the spool valve 29 via the first CTA oil passage 56 and a CTA-side retard chamber that communicates with the spool valve 29 via the second CTA oil passage 55. It is partitioned by the third vane 43 into 47b. The OPA side advance oil passages 51 and 52 are connected to the electromagnetic shut-off valve 17 via the hydraulic oil discharge passages 81 to 83, as will be described later.

  The first vane 41 accommodates a lock pin 33 and a lock pin spring 34 (see FIG. 2), and only when the hydraulic oil is not supplied to the lock pin release oil passage, The tip of the lock pin 33 is fitted into the lock hole 25 a formed in the back plate 25 by the spring force. Note that the lock hole 25a is formed at a position where the lock pin 33 is fitted when the rotor 23 reaches the start cam phase (in this embodiment, the most retarded angle phase) with respect to the housing 22.

(Bypass valve)
As shown in FIG. 4, the bypass valve 36 has a communication groove 36 a in the middle thereof, and slides into a valve holding hole formed in the third vane 43 in parallel with the axis of the exhaust camshaft 5. It is held freely. The bypass valve spring 37 is accommodated in a spring holding hole formed in the shaft center of the bypass valve 36, and always biases the bypass valve 36 toward the back plate 25 side. In the third vane 43, a hydraulic pressure introduction hole 43b for introducing hydraulic pressure from the electromagnetic shut-off valve 17 to one end of the bypass valve 36, a communication oil passage 43d connecting the CTA side advance chamber 47a and the valve holding hole 43a. In addition, a communication oil passage 43c that connects a central oil passage 57 and a valve holding hole 43a, which will be described later, is formed. As shown in FIG. 4A, when the hydraulic pressure is introduced into the hydraulic pressure introduction hole 43b, the bypass valve 36 moves to the front plate 24 side, and both the communicating oil passages 43c and 43d are blocked. 4B, when the hydraulic pressure is discharged from the hydraulic pressure introduction hole 43b, the bypass valve 36 moves to the back plate 25 side by the spring force of the bypass valve spring 37, and the communication groove of the bypass valve 36 Both communicating oil passages 43c and 43d communicate with each other through 36a.

(Electromagnetic shut valve)
As shown in FIG. 5, the electromagnetic shut-off valve 17 includes an ON / OFF solenoid 91, a spool 92 having two lands 92a and 92b and a communication groove 92c, and a return that urges the spool 92 toward the ON / OFF solenoid 91. A spring 93 and a drain passage 94 are provided. As shown in FIG. 5A, when the ON / OFF solenoid 91 is in a non-excited state, the spool 92 urged by the return spring 93 is positioned on the right side in the drawing, so that the hydraulic oil supply oil passage 16 (16a 16b) communicates via the communication groove 92c, and the hydraulic oil from the oil pump 14 is supplied to both the VTC actuators 20 and 21, while the hydraulic oil discharge path 83 is closed by the land 92b. Further, as shown in FIG. 5B, when the ON / OFF solenoid 91 is excited, the spool 92 moves to the left in the figure, so that the hydraulic oil supply oil passage 16a is closed by the land 92a. The oil supply oil passage 16b and the hydraulic oil discharge passage 83 communicate with the drain passage 94 through the communication groove 92c. As a result, the hydraulic oil is discharged from both the VTC actuators 20 and 21, and in particular, the hydraulic oil is quickly discharged from the OPA side advance chambers 45a and 46a.

<Engine ECU>
As shown in FIG. 6, the engine ECU 70 includes an input interface 71, a target cam phase setting unit 72, a target lift amount setting unit 73, and a starting failure determination control unit 74 (failure determination means, failure drive means). ) And an output interface 75. The input interface 71 receives detection signals from the intake cam angle sensor 18 and the exhaust cam angle sensor 19 in addition to various operation information such as the accelerator opening, the intake air amount, and the coolant temperature. The target cam phase setting unit 72 sets the target cam phases of the intake / exhaust camshafts 4 and 5 based on various input information, and outputs drive signals to both VTC actuators 20 and 21 via the output interface 75. . The target lift amount setting unit 73 sets the target lift amounts of the intake and exhaust valves 2 and 3 based on various input information, and outputs drive signals to both the VLC mechanisms 50 and 51 via the output interface 75. Further, the start-time failure determination control unit 74 determines the failure of the VTC actuators 20 and 21 by driving the ON / OFF solenoid 91 and the linear solenoid 31 according to a predetermined procedure when the engine E is started. The ON / OFF solenoid 91 and the linear solenoid 31 are driven and controlled according to the above.

<< Operation of Embodiment >>
Hereinafter, the operation of the present embodiment will be described with reference to FIGS. 7 to 18 (schematic operation diagrams, flowcharts, and graphs).
<Control during normal operation>
During normal operation of the engine E, the engine ECU 70 repeatedly executes normal operation control of both the VTC actuators 20 and 21 with a predetermined control interval (for example, 10 ms). When the normal operation control is started, the engine ECU 70 determines the target cam phase of both the camshafts 4 and 5 based on the various operation information described above, and then supplies the drive current for realizing the target cam phase to the two VTC actuators 20, 21 to the linear solenoid 31 as appropriate. Further, the engine ECU 70 executes feedback control of the cam phase for both the camshafts 4 and 5 based on the output signals of both the cam angle sensors 18 and 19.

(Advanced operation)
For example, when the exhaust camshaft 5 is advanced during operation of the engine E, the engine ECU 70 moves the spool 39 to the advanced position (rightward in the figure) by the linear solenoid 31 as shown in FIG. Then, the hydraulic oil supplied from the oil pump 14 via the hydraulic oil supply oil passage 16 flows into the OPA side advance chambers 45a and 46a via the spool 39 and the OPA side advance oil passages 51 and 52, The first and second vanes 41 and 42 are rotated relative to the advance side. The hydraulic oil in the OPA side retarding chambers 45b and 46b is discharged to the outside from the left side of the spool 39 through the OPA side retarding oil passages 53 and 54.

  On the other hand, in the CTA 63, the second CTA oil passage 55 and the central oil passage 57 communicate with each other via the spool 39 moved to the advance position. Then, the advance cam torque acts on the exhaust camshaft 5 and the second valve body 26b of the reed valve 26 opens each time the rotor 23 rotates relative to the housing 22 toward the advance side. The hydraulic oil in 47b flows into the CTA side advance chamber 47a and relatively rotates the third vane 43 to the advance side. Further, when the retard side cam torque is applied, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil.

  By the operation of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 rotates relative to the housing 22 in the clockwise direction in the drawing, and the exhaust camshaft 5 advances. The hydraulic oil is supplied to the CTA 63 until the CTA 63 is satisfied at the start of operation of the engine E. Further, during normal operation of the engine E, no driving current is supplied to the electromagnetic shut valve 17 (the hydraulic oil supply oil passages 16a and 16b are communicated), and the electromagnetic shut valve 17 is held by the hydraulic oil from the oil pump 14 and is also bypass valve 36. Moves to the front plate 24 side and interrupts the flow of hydraulic oil between the communicating oil passages 43c and 43d.

(Retarded operation)
When retarding the exhaust camshaft 5 during operation of the engine E, the engine ECU 70 moves the spool 39 to the retard position (leftward in the figure) by the linear solenoid 31 as shown in FIG. Then, the hydraulic oil supplied from the oil pump 14 via the hydraulic oil supply oil passage 16 flows into the OPA side retardation chambers 45b and 46b via the spool 39 and the OPA side retardation oil passages 53 and 54, The first and second vanes 41 and 42 are rotated relative to the retard side. The hydraulic oil in the OPA side advance chambers 45a and 46a is discharged to the outside from the right side of the spool 39 via the OPA side advance oil passages 51 and 52.

  On the other hand, in the CTA 63, the first CTA oil passage 56 and the central oil passage 57 communicate with each other via the spool 39 moved to the retard position. Then, the retard cam torque acts on the exhaust camshaft 5 and the first valve body 26a of the reed valve 26 opens each time the rotor 23 rotates relative to the housing 22 toward the retard side, and the CTA side advance chamber is opened. The hydraulic oil in 47a flows into the CTA side retard chamber 47b and relatively rotates the third vane 43 to the retard side. Further, when the cam torque on the advance side acts, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil.

(Holding operation)
When the target cam phase is obtained by the advance angle operation or the retard angle operation described above, the engine ECU 70 moves the spool 39 to the holding position (center in the figure) by the linear solenoid 31 as shown in FIG. Then, the hydraulic oil in the OPA side advance chambers 45a and 46a and the OPA side retard chambers 45b and 46b is contained by the spool 39, and the first and second vanes 41 and 42 cannot move. On the other hand, in the CTA 63, the hydraulic oil cannot move between the CTA side advance chamber 47a and the CTA side retard chamber 47b, and the third vane 43 cannot move. By the operations of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 does not rotate relative to the housing 22, and the cam phase of the exhaust camshaft 5 is maintained.

<Fail judgment control at start-up>
When the ignition switch is turned on, the engine ECU 70 executes start-up failure determination control shown in the flowchart of FIG. 10 and the graph of FIG. Note that the graphs of FIG. 11 (FIGS. 14, 15, 17, and 18 described later) show temporal changes in the cam phase, the ON / OFF solenoid 91, and the drive duty of the linear solenoid 31. When the start-time failure determination control is started, the engine ECU 70 determines whether or not the engine E is being cranked in step S1 of FIG. 10, and if this determination is No, returns to the start without performing any processing. .

  When the driver operates the ignition key or the engine start button and the determination in step S1 becomes Yes, the engine ECU 70 turns on the ON / OFF solenoid 91 in step S2, as shown in FIGS. 11 and 12, and step S3. The linear solenoid 31 is driven with a predetermined drive duty (for example, 20 to 30%).

(Shut valve failure judgment)
Next, the engine ECU 70 determines whether or not the ON / OFF solenoid 91 has failed in step S4. If this determination is Yes, the process proceeds to "ON / OFF solenoid failure processing" described later in step S5. . In the present embodiment, the fail determination of the ON / OFF solenoid 91 is performed based on whether or not cam phase fluctuation (oscillation) occurs even after a predetermined time Tt has elapsed since the cranking start. In the oscillation of the cam phase, when the lock pin 33 does not operate due to the failure of the ON / OFF solenoid 91, the rotor 23 and the housing 22 are not locked at the start cam phase, and the advance side and the retard side are caused by cam torque fluctuations. Caused by alternating relative rotations between the two. Note that the predetermined time Tt is set to a value that can sufficiently shift to the starting cam phase even when the cam phase is on the most advanced angle side at the start of cranking of the engine E.

(Linear solenoid fail judgment)
If the determination in step S4 is No, the engine ECU 70 determines whether or not the linear solenoid 31 has failed in step S6. If this determination is Yes, the "processing during linear solenoid failure" described later in step S7. ”. In the case of the present embodiment, this fail determination is made by not supplying current to the linear solenoid 31 due to disconnection of the lead wire or the like, or the difference ΔD between the target drive duty Dtgt of the linear solenoid 31 and the actual drive duty Dreal is predetermined. This is performed depending on whether or not the failure determination drive duty Dth is exceeded. The deviation of the actual drive duty Dreal from the target drive duty Dtgt occurs when the spool 39 bites foreign matter.

  If the determination in step S6 is also No (that is, both the ON / OFF solenoid 91 and the linear solenoid 31 are normal), as shown in FIG. 12, the hydraulic oil supply oil passage 16b and the hydraulic oil discharge passage 83 are connected to the drain passage. 94, the hydraulic oil supplied to the lock pin 33 is discharged, the hydraulic oil supplied to the bypass valve 36 is also discharged, and the hydraulic oil in the OPA side advance chambers 45a and 46a is further discharged. The oil is discharged to the drain passage 94 through the OPA side advance oil passages 51 and 52 and the hydraulic oil discharge passages 81 to 83.

  Accordingly, the lock pin 33 is urged toward the back plate 25 by the lock pin spring 34 and can be fitted into the lock hole 25 a formed in the back plate 25. In the CTA 63, the bypass valve 36 moves to the back plate 25 side (upward in FIG. 12) by the spring force of the bypass valve spring 37, so that the communication oil passages 43c and 43d and the communication groove 36a of the bypass valve 36 are connected. Thus, the hydraulic oil can be moved from the CTA side advance chamber 47a to the CTA side retard chamber 47b.

  When the hydraulic oil is discharged from the OPA side advance chambers 45a and 46a, the rotational resistance of the rotor 23 toward the retard side is reduced. Therefore, when cranking of the engine E is started, the bias spring 28 is biased in the retarding direction, so that the rotor 23 rotates toward the retarding side with respect to the housing 22 as shown in FIG. To do. When the rotor 23 rotates relative to the housing 22 to the most retarded phase (when the start cam phase is established), the lock pin 33 biased by the lock pin spring 34 is fitted into the lock hole 25a. The rotor 23 and the housing 22 are locked at the start cam phase.

  Next, the engine ECU 70 determines whether or not the engine E has started (complete explosion) in step S8, and repeats the determination in step S8 while this determination is No. The engine E start determination may be made based on whether or not the engine rotation speed has reached a predetermined complete explosion determination threshold (for example, 500 rpm).

  When the engine E is started and the determination in step S8 is Yes, the engine ECU 70 turns off the ON / OFF solenoid 91 in step S9, and sets the drive duty of the linear solenoid 31 to 0% in step S10. Next, the engine ECU 70 determines whether or not a predetermined standby time Tcd has elapsed after the process of step S10 in step S11, and repeats the determination of step S11 while this determination is No. The standby time Tcd is the time required for normal operation of the exhaust side VTC actuator 21 (after the ON / OFF solenoid 91 is turned off, the lock pin 33 comes out of the lock hole 25a, and hydraulic oil is supplied to the exhaust side VTC actuator 21. Longer than the time required to be satisfied).

  When the standby time Tcd has elapsed and the determination in step S11 is Yes, the engine ECU 70 proceeds to the above-described normal operation control in step S12, and starts driving control of the linear solenoid 31 based on the target cam phase.

<Processing during ON / OFF solenoid failure>
When the determination in step S4 of FIG. 10 is Yes, the engine ECU 70 executes the ON / OFF solenoid failure processing shown in the flowchart of FIG. 13 and the graphs of FIGS. When the ON / OFF solenoid failure process is started, the engine ECU 70 determines whether or not the engine E has been started in step S21 in FIG. 13 and repeats the determination in step S21 while this determination is No. In this case, since the ON / OFF solenoid 91 has failed, the rotor 23 and the housing 22 are not locked by the lock pin 33 at the start cam phase. However, since the linear solenoid 31 is in the retarded position, the exhaust side VTC actuator 21 is held near the most retarded phase and the engine E is started.

  When the engine E is started and the determination in step S21 is Yes, the engine ECU 70 determines whether or not the linear solenoid 31 has failed in step S23 after turning the ON / OFF solenoid 91 OFF in step S22. If this determination is Yes, a failure warning lamp (not shown) is turned on to notify the driver of the failure of both solenoids 31, 91 in step S24. In this case, as shown in FIG. 14, since the ON / OFF solenoid 91 is in the OFF state and the linear solenoid 31 is in the non-operating state, the exhaust side VTC actuator 21 is held in the cam phase at the start, and the maintenance factory It is possible to travel to The reason why the ON / OFF solenoid 91 is turned OFF in step S22 is that, when the ON / OFF solenoid 91 is activated for some reason after shifting to the normal operation control, the exhaust side VTC actuator 21 is in operation during the operation of the engine E. This is because there is a risk of inadvertently locking at the start cam phase.

  On the other hand, if the determination in step S23 is No, the engine ECU 70 turns on a failure warning lamp (not shown) that informs the driver of the failure of the ON / OFF solenoid 91 in step S25, and then performs control during normal operation in step S26. Then, the drive control of the linear solenoid 31 based on the target cam phase is started (see FIG. 15). This is because normal operation control can be executed as long as the engine E starts even if the ON / OFF solenoid 91 fails.

<Processing during linear solenoid failure>
When the determination in step S6 of FIG. 10 is Yes, the engine ECU 70 executes the linear solenoid failure processing shown in the flowchart of FIG. 16 and the graphs of FIGS. When the linear solenoid failure process is started, the engine ECU 70 determines whether or not the linear solenoid 31 is energized in step S31 of FIG. 16, and if this determination is No, the engine ECU 70 determines whether the linear solenoid 31 is energized in step S32. A failure warning lamp (not shown) that informs the driver of the failure is turned on, and the process ends. In this case, as shown in FIG. 17, the engine ECU 70 keeps the ON / OFF solenoid 91 ON (that is, the exhaust side VTC actuator 21 is locked at the start cam phase by the lock pin 33). The engine E is started and operated. In this state, since the cam phase is fixed at the most retarded angle, traveling to a maintenance shop or the like is possible.

  If the determination in step S31 is Yes, the engine ECU 70 determines whether or not the engine E has been started in step S33, and repeats the determination in step S33 while this determination is No. Also in this case, since the ON / OFF solenoid 91 is ON, the engine E can be started.

  When the engine E is started and the determination in step S33 is Yes, the engine ECU 70 operates the linear solenoid 31 in the cleaning mode for a predetermined time in step S34. As shown in FIG. 18, the cleaning mode is a mode in which the drive duty of the linear solenoid 31 is alternately repeated between 0% and 100%, thereby eliminating the foreign matter that has been caught in the spool 39. There is a possibility that the linear solenoid 31 operates normally.

  Next, the engine ECU 70 determines again the failure of the linear solenoid 31 in step S35, and if this determination is No (that is, if the failure of the linear solenoid 31 has been eliminated), the ON / OFF solenoid 91 is turned on in step S36. In step S37, the drive duty of the linear solenoid 31 is set to 0%. Next, the engine ECU 70 determines whether or not a predetermined standby time Tcd has elapsed after the processing of step S37 in step S38, and repeats the determination of step S38 while this determination is No.

  When the standby time Tcd has elapsed and the determination in step S38 is Yes, the engine ECU 70 proceeds to normal operation control in step S39, and starts driving control of the linear solenoid 31 based on the target cam phase.

  On the other hand, if the determination in step S35 is Yes, the engine ECU 70 turns on a failure warning lamp (not shown) that informs the driver of the failure of the linear solenoid 31 in step S32, and keeps the ON / OFF solenoid 91 ON. The engine E is started and operated.

  In the present embodiment, by adopting the above-described configuration, it is possible to detect the failure of the exhaust-side VTC actuator 21 without using a special sensor, and also when the ON / OFF solenoid 91 or the linear solenoid 31 fails, the driver The engine E can be started and operated to bring a car to a maintenance shop or the like.

  Although the description of the specific embodiment is finished as above, the present invention is not limited to the above embodiment and can be widely modified. For example, although the above embodiment is an application of the present invention to an in-line four-cylinder DOHC gasoline engine, it is naturally applicable to a V-type engine, a diesel engine, or the like. In the above embodiment, the failure determination process for the exhaust-side VTC actuator has been described. However, the failure determination process for the intake-side VTC actuator can also be performed in the same manner. In the above embodiment, the VTC actuator provided with OPA and CTA is used. However, a VTC actuator having only OPA may be used. In the CTA of the embodiment, both the advance side hydraulic chamber and the retard side hydraulic chamber are formed in the third vane chamber. However, for example, the advance side hydraulic chamber is formed in the second vane chamber, The corner side hydraulic chamber may be formed in the third vane chamber. In the above embodiment, the starting cam phase is set to the most retarded angle, but may be set to the most advanced angle or between the most retarded angle and the most advanced angle. In addition, the specific configuration of the engine and the VLC mechanism including the VTC actuator can be changed as long as it does not depart from the gist of the present invention.

It is a principal part perspective view of the engine which concerns on embodiment. It is a disassembled perspective view of the VTC actuator which concerns on embodiment. It is a schematic block diagram of the VTC actuator which concerns on embodiment. It is sectional drawing which shows the operation | movement aspect of the bypass valve which concerns on embodiment. It is sectional drawing which shows the operation | movement aspect of the electromagnetic shut valve which concerns on embodiment. It is a block diagram which shows schematic structure of engine ECU which concerns on embodiment. It is a mimetic diagram showing advance angle operation of the VTC actuator concerning an embodiment. It is a schematic diagram which shows the retardation operation | movement of the VTC actuator which concerns on embodiment. It is a schematic diagram which shows holding | maintenance operation | movement of the VTC actuator which concerns on embodiment. It is a flowchart which shows the procedure of the starting failure determination control which concerns on embodiment. It is a graph which shows the change of the cam phase which concerns on embodiment, and the drive duty of both solenoids. It is a schematic diagram which shows the action | operation at the time of the start of the VTC actuator which concerns on embodiment. It is a flowchart which shows the procedure of the process at the time of ON / OFF solenoid failure which concerns on embodiment. It is a graph which shows the change of the cam phase which concerns on embodiment, and the drive duty of both solenoids. It is a graph which shows the change of the cam phase which concerns on embodiment, and the drive duty of both solenoids. It is a flowchart which shows the procedure of the process at the time of ON / OFF solenoid failure which concerns on embodiment. It is a graph which shows the change of the cam phase which concerns on embodiment, and the drive duty of both solenoids. It is a graph which shows the change of the cam phase which concerns on embodiment, and the drive duty of both solenoids.

Explanation of symbols

5 Exhaust camshaft 10 Crankshaft 17 Electromagnetic shut valve (hydraulic oil supply / discharge means)
21 Exhaust-side VTC actuator 22 Housing (first rotating member)
23 Rotor (second rotating member)
29 Spool valve (supply switching means)
31 Linear solenoid 31 Both solenoids 33 Lock pin (cam phase fixing means)
36 Bypass valve (invalidation means)
36a Communication groove 37 Bypass valve spring (biasing means)
45a, 46a OPA side advance chamber (advance side oil chamber)
45b, 46b OPA side retarding chamber (retarding side oil chamber)
61 1st OPA (hydraulic actuator)
62 2nd OPA (Hydraulic Actuator)
63 CTA (cam torque actuator)
70 Engine ECU
74 Start-up failure determination control unit (failure determination means)
81-83 Hydraulic oil discharge path (hydraulic oil discharge path)
91 ON / OFF solenoid (drive means in case of failure)
E engine

Claims (4)

A first rotating member that rotates in synchronization with the crankshaft;
A second rotating member that rotates integrally with the camshaft and is connected to the first rotating member so as to be relatively rotatable;
An advance angle oil chamber and a retard angle oil chamber are provided between the first rotation member and the second rotation member, and operate in at least one of the advance angle oil chamber and the retard angle oil chamber. A hydraulic actuator that changes the cam phase by supplying oil; and
Supply switching means used for hydraulic oil supply switching control for the advance side oil chamber and the retard side oil chamber;
A cam phase variable internal combustion engine equipped with a cam phase variable device having hydraulic oil supply / discharge means used for hydraulic oil supply / discharge control with respect to the supply switching means,
A hydraulic oil discharge path for communicating any one of the advance side oil chamber and the retard side oil chamber and the hydraulic oil supply / discharge means without the supply switching means;
A failure determining means for determining a failure related to the cam phase varying device;
A cam phase variable internal combustion engine comprising: a drive unit for failure when draining the hydraulic fluid from the supply switching unit by the hydraulic fluid supply / discharge unit when the failure is determined by the failure determination unit organ. A cam torque actuator that uses a cam torque acting on the cam shaft as a driving force, and changes or holds a relative angle between the first rotating member and the second rotating member;
Invalidating means for invalidating the operation of the cam torque actuator,
2. The cam phase variable internal combustion engine according to claim 1, wherein when the failure is determined by the failure determination unit, the failure drive unit also operates the invalidation unit. Cam phase fixing means for coupling the first rotating member and the second rotating member with a predetermined start cam phase;
3. The cam phase variable according to claim 1, wherein the failure driving means also activates the cam phase fixing means when a failure is determined by the failure determination means. 4. Type internal combustion engine.   And a biasing means that is interposed between the first rotating member and the second rotating member and biases the first rotating member and the second rotating member toward the start cam phase. The cam phase variable internal combustion engine according to any one of claims 1 to 3, characterized in that:

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