JP5787738B2 - Valve timing adjustment system - Google Patents

Description

  The present invention relates to a valve timing adjustment system that adjusts the opening / closing timing of an intake valve or an exhaust valve of an engine.

  2. Description of the Related Art Conventionally, a valve timing adjustment system that adjusts the opening / closing timing of an intake valve or an exhaust valve by changing the rotational phase of an engine crankshaft and a camshaft is known. In the valve timing adjustment system disclosed in Patent Document 1, hydraulic oil is supplied to an advance chamber or a retard chamber in a housing that rotates together with a crankshaft, so that a vane rotor that rotates together with a camshaft is rotated relative to each other. To adjust the opening and closing timing.

  Here, it is known that the relative rotation between the housing and the vane rotor is restricted by a restricting member in order to suppress the hitting sound generated by the housing and the vane rotor striking each other. In the valve timing adjustment system disclosed in Patent Document 1, the restricting member is in a restricting position for engaging with the housing and a restricting releasing position for releasing the engagement with the housing in accordance with the pressure of the hydraulic oil in the restricting release chamber. Operates selectively. The regulation release chamber is supplied with hydraulic oil from the oil pump via the advance chamber.

  The time required for the restriction release chamber to be filled with the hydraulic oil and the pressure of the hydraulic oil to increase is longer than that of the advance chamber. Therefore, in the valve timing adjustment system disclosed in Patent Document 1, when the opening / closing timing is changed during the relative rotation restriction by the restriction member, the hydraulic oil in the advance chamber is increased before the pressure of the hydraulic oil in the restriction release chamber rises. As the pressure increases, the vane rotor may try to rotate relative to the housing before the restricting member comes out of the engagement hole of the housing.

Japanese Patent Laid-Open No. 11-50820

  In the valve timing adjustment system disclosed in Patent Document 1, when the opening / closing timing is changed during the relative rotation restriction by the restriction member, the vane rotor rotates relative to the housing before the restriction member comes out of the engagement hole of the housing. Due to the movement, there is a problem that the restricting member is pressed against the inner wall of the engaging hole of the housing, and the restricting member cannot be removed from the engaging hole of the housing. If the restricting member does not come out of the engagement hole of the housing in this way, the relative rotation restriction between the housing and the vane rotor cannot be released, and the opening / closing timing cannot be adjusted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a valve timing adjustment system that can suppress the restriction release failure of the relative rotation between the housing and the vane rotor.

The invention according to claim 1 is a valve timing adjustment system that adjusts the opening / closing timing of an intake valve or an exhaust valve that is driven to open / close by the driven shaft by changing the rotational phase of the drive shaft and the driven shaft of the engine. The valve timing adjustment system includes a housing, a vane rotor, a regulating member, a pump, a switching valve, a pressure adjustment valve, a pressure detection unit, and a plurality of control units.
The housing rotates integrally with one of the drive shaft and the driven shaft, and the vane rotor rotates integrally with the other of the drive shaft and the driven shaft. The vane rotor is integrally formed from a boss portion and a vane portion accommodated in the housing, and is rotatable relative to the housing. The vane section partitions the interior of the housing into an advance chamber and a retard chamber.

The restricting member is slidably supported by the vane rotor, and can engage with the housing to restrict relative rotation between the housing and the vane rotor. The restricting member is separated from the housing according to the pressure of the working fluid in the restriction releasing chamber communicating with the advance chamber or the retard chamber. When the restricting member is separated from the housing, the relative rotation restriction is released.
The pump can supply working fluid to the advance chamber, the retard chamber, and the deregulation chamber. A working fluid is supplied to the regulation release chamber via the advance chamber or the retard chamber. The switching valve is provided between the pump and the advance chamber and the retard chamber. This switching valve operates at a position where the pump and the advance chamber are connected and a position where the pump and the retard chamber are connected. The pressure adjusting valve can adjust the inflow pressure of the working fluid flowing into the switching valve. The pressure detection means detects the inflow pressure.

As the control means, an opening / closing timing adjustment control means, a restriction non-release determination means, a first pressure determination means, and a forced restriction release control means are provided.
When there is a command to change the opening / closing timing, the opening / closing timing adjustment control means operates the switching valve so that the working fluid is supplied to the advance chamber or the retard chamber, thereby moving the vane rotor to the housing on the advance side or on the retard side. Turn relative to the corner.
The restriction non-release determining means determines whether or not the relative rotation restriction is not released when a predetermined time has elapsed since the opening / closing timing adjustment control was started during the relative rotation restriction by the restriction member.
In a case where the restriction unrelease determination unit determines that the relative rotation restriction is not released, the first pressure determination unit determines whether or not the inflow pressure exceeds an upper limit value of a predetermined restriction releaseable pressure range.

When the first pressure determining means determines that the inflow pressure exceeds the upper limit value of the deregulatable pressure range, the forcible deregulation control means sets the state in which the inflow port of the switching valve communicates with the advance chamber or the retard chamber. While maintaining, operating the pressure regulating valve so as to reduce the inflow pressure , the pressure of the working fluid in the advance chamber and the retard chamber communicating with the inflow port is reduced.
Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member, the relative rotation restriction between the housing and the vane rotor is restricted because the pressure of the working fluid in the advance chamber or the retard chamber is too high. If it cannot be released, the inflow pressure decreases after a predetermined time. As a result, the torque acting on the vane rotor is reduced, and the force pressing the regulating member against the inner wall of the engagement hole of the housing is reduced. For this reason, the restricting member is easily removed from the engagement hole of the housing, so that it is possible to suppress the restriction release failure of the relative rotation between the housing and the vane rotor.

In the invention according to claim 2, the pressure adjusting valve can adjust the inflow pressure to a predetermined high pressure and low pressure. Further, when the first pressure determining means determines that the inflow pressure exceeds the upper limit value of the restriction releaseable pressure region, the forced restriction release control means operates the pressure regulating valve so that the inflow pressure becomes a low pressure.
Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member, the relative rotation restriction between the housing and the vane rotor is restricted because the pressure of the working fluid in the advance chamber or the retard chamber is too high. If it cannot be released, the inflow pressure decreases to a low pressure after a predetermined time. Thereby, it is possible to suppress the relative rotation restriction release failure. Moreover, the pressure control valve can employ a simple structure that can adjust the inflow pressure in two stages.

A valve timing adjustment system according to a third aspect of the present invention includes second pressure determination means. When the first pressure determining means determines that the inflow pressure is equal to or lower than the upper limit value of the deregulatable pressure range, the second pressure determining means determines whether the inflow pressure is lower than the lower limit value of the deregulated pressure range. To do. Further, the forcible deregulation control means, when the second pressure determination means determines that the inflow pressure is below the lower limit value of the deregulatable pressure range, operates the pressure adjustment valve so that the inflow pressure increases, thereby controlling the deregulation chamber. Increase the pressure of the working fluid.
Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member, the relative rotation restriction between the housing and the vane rotor is restricted due to the pressure of the working fluid in the advance chamber or the retard chamber being too low. If it cannot be released, the inflow pressure increases after a predetermined time. As a result, the axial force in the direction in which the restricting member is separated from the housing by the pressure of the working fluid in the restriction releasing chamber is increased. For this reason, the restricting member is easily removed from the engagement hole of the housing, so that it is possible to suppress the restriction release failure of the relative rotation between the housing and the vane rotor.

In the invention according to claim 4, the pressure adjusting valve can adjust the inflow pressure to a predetermined high pressure and low pressure. The forced restriction release control means operates the pressure adjustment valve so that the inflow pressure becomes low when the first pressure determination means determines that the inflow pressure exceeds the upper limit value of the restriction releaseable pressure range. On the other hand, the forced restriction release control means operates the pressure regulating valve so that the inflow pressure becomes high when the second pressure determination means determines that the inflow pressure falls below the lower limit value of the restriction releaseable pressure range. .
Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member, the relative rotation restriction between the housing and the vane rotor is restricted due to the pressure of the working fluid in the advance chamber or the retard chamber being too low. If it cannot be released, the inflow pressure increases to a high pressure after a predetermined time. Thereby, it is possible to suppress the relative rotation restriction release failure. Moreover, the pressure control valve can employ a simple structure that can adjust the inflow pressure in two stages.

In the invention according to claim 5, when the first pressure determining means determines that the inflow pressure exceeds the upper limit value of the deregulatable pressure range, the forcible deregulation control means falls within the deregulatable pressure range. By operating the pressure regulating valve, the pressure of the working fluid in at least one of the advance chamber and the retard chamber is reduced.
Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member, the relative rotation restriction between the housing and the vane rotor is restricted because the pressure of the working fluid in the advance chamber or the retard chamber is too high. When it becomes impossible to cancel, the inflow pressure falls within the pressure range where the restriction can be released after a predetermined time. Thereby, it is possible to suppress the relative rotation restriction release failure.

In the invention according to claim 6, the forced restriction release control means determines that the first pressure determination means determines that the inflow pressure is equal to or lower than the upper limit value of the restriction releaseable pressure range, and the inflow pressure is within the restriction releaseable pressure range. When the second pressure determination means determines that the value is equal to or greater than the lower limit value, it is determined that the regulating member or the switching valve is abnormal.
Therefore, for example, by turning on a warning lamp or the like to notify the driver of the abnormality, the driver can respond quickly.

In the invention according to claim 7, the regulating member forms a circumferential clearance with the housing during the relative rotation regulation. The unregulated determination unit calculates a rotation phase of the driven shaft with respect to the drive shaft when the opening / closing timing adjustment control is started during the relative rotation restriction. Further, the unregulated determination unit calculates a rotation phase of the driven shaft with respect to the drive shaft when a predetermined time has elapsed after the opening / closing timing adjustment control is started. Further, the restriction non-releasing determination means determines that the relative rotation restriction is performed when the difference between the rotation phase at the start of the opening / closing timing adjustment control and the rotation phase at the elapse of a predetermined time is equal to or less than a predetermined angle corresponding to the circumferential gap. It is determined that it has not been released.
Therefore, it is possible to determine whether the relative rotation restriction has not been released based on signals from the rotational position sensor of the drive shaft and the rotational position sensor of the driven shaft.

In the invention described in claim 8, the forcible restriction release control means controls the relative rotation when the rotational phase of the driven shaft with respect to the drive shaft changes after the pressure regulating valve is operated so that the inflow pressure decreases or increases. It is determined that the pressure has been released, and the inflow pressure is returned to the value immediately before operating the pressure regulating valve.
Therefore, the opening / closing timing control can be restarted quickly.

1 is a diagram showing an engine to which a valve timing adjustment system according to a first embodiment of the present invention is applied. It is a figure which shows the valve timing adjustment system by 1st Embodiment of this invention. It is the III-III sectional view taken on the line of FIG. It is a figure which shows the relationship between the inflow pressure which flows in into the hydraulic control valve of FIG. 2, and the regulation cancellation | release time which cancels the relative rotation regulation by a lock pin. In the valve timing adjusting device shown in FIG. 2, the vane rotor is relatively rotated before the lock pin fitting portion comes out of the fitting recess of the shoe housing, and the lock pin is sandwiched between the vane rotor and the shoe housing in the circumferential direction. It is sectional drawing which shows a state typically. It is the flowchart which showed the processing flow regarding the control action of the electronic controller of FIG. Changes in the target rotation phase of the camshaft, the actual rotation phase of the camshaft, the inflow pressure command value, and the actual inflow pressure after starting the opening / closing timing adjustment control during the relative rotation restriction by the lock pin of FIG. It is a time chart shown, and is a case where the relative rotation restriction is released immediately after the start of the opening / closing timing adjustment control. Changes in the target rotation phase of the camshaft, the actual rotation phase of the camshaft, the inflow pressure command value, and the actual inflow pressure after starting the opening / closing timing adjustment control during the relative rotation restriction by the lock pin of FIG. FIG. 6 is a time chart when the relative rotation restriction is not released within a predetermined time after the opening / closing timing adjustment control is started. It is the flowchart which showed the processing flow regarding the control action of the electronic controller of the valve timing adjustment system by 2nd Embodiment of this invention. The target rotation phase of the camshaft, the actual rotation phase of the camshaft, the inflow pressure command value, and the actual value after starting the opening / closing timing adjustment control during the relative rotation restriction by the lock pin in the conventional valve timing adjustment system It is a time chart which shows the change of inflow pressure, Comprising: Relative rotation regulation is not cancelled | released within predetermined time after starting opening-and-closing timing adjustment control.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
The valve timing adjustment system according to the first embodiment of the present invention is applied to the engine shown in FIG. In this engine 1, a chain is connected to a gear 3 fixed to a crankshaft 2 as a “drive shaft”, a gear 5 fixed to a camshaft 4 as a “driven shaft”, and a gear 7 fixed to the camshaft 6. 8 is wound, and the rotational force is transmitted from the crankshaft 2 to the camshafts 4 and 6. The camshaft 4 drives the intake valve 9 to open and close, and the camshaft 6 drives the exhaust valve 10 to open and close.

The valve timing adjustment system 12 according to the first embodiment adjusts the opening / closing timing of the intake valve 9. When the camshaft 4 is rotated relative to the gear 5 forward in the rotational direction, the opening / closing timing of the intake valve 9 is advanced. This advancement of the opening / closing timing of the intake valve 9 is referred to as “advancing”.
Further, when the camshaft 4 is rotated relative to the gear 5 in the rotational direction rearward, the opening / closing timing of the intake valve 9 is delayed. Thus, delaying the opening / closing timing of the intake valve 9 is referred to as “retarding”.
Hereinafter, the valve timing adjustment system 12 will be described in detail.

  As shown in FIGS. 2 and 3, the valve timing adjustment system 12 includes a hydraulic control type valve timing adjustment device 14 that uses hydraulic oil as a working fluid, an oil pump 78, a hydraulic control valve 88 as a “switching valve”, “ A variable pressure relief valve 98 as an “pressure adjusting valve”, an electronic control device 102 and the like are provided. The electronic control device 102 functions as “opening / closing timing adjustment control means”, “unregulated release determination means”, “forced restriction release control means”, and “first pressure determination means”.

The valve timing adjusting device 14 includes a housing 16, a vane rotor 52, a lock pin 64 as a “regulating member”, and the like.
The housing 16 has a shoe housing 18 and a sprocket 30. The shoe housing 18 includes a cylindrical portion 20, a bottom portion 22 that closes one end of the cylindrical portion 20, and a plurality of shoes 24, 26, and 28 that protrude radially inward from the cylindrical portion 20. The shoes 24 to 28 are provided apart from each other in the circumferential direction of the cylindrical portion 20.

  The sprocket 30 is disposed so as to close the opening of the shoe housing 18 and is rotatably supported by the camshaft 4. The sprocket 30 and the sprocket 30 are integrally fixed coaxially with a bolt 74. A gear 5 is formed on the outer periphery of the sprocket 30, and the rotation of the crankshaft 2 is transmitted to the gear 5 via a chain 8 (see FIG. 1). Thereby, the housing 16 rotates integrally with the crankshaft 2.

  The vane rotor 52 is accommodated in the housing 16 and is provided to be rotatable relative to the housing 16. The vane rotor 52 includes a boss portion 54 and a plurality of vane portions 56, 58, and 60 that protrude from the boss portion 54 in the radially outward direction. The vane rotor 52 and the camshaft 4 are integrally and coaxially fixed by bolts 76. Thereby, the vane rotor 52 rotates integrally with the camshaft 4.

Here, as shown in FIG. 3, the clockwise direction on the paper is the advance direction, and the counterclockwise direction is the retard direction.
Between the boss portion 54 of the vane rotor 52 and the cylindrical portion 20 of the shoe housing 18, three vane housing chambers 32 partitioned by the shoes 24 to 28 are formed. Each vane accommodating chamber 32 accommodates each vane portion 56-60 so as to be relatively rotatable in the advance angle direction and the retard angle direction. The advance angle hydraulic chambers 34-38 and the retard angle hydraulic chamber 40 are accommodated by the vane portions 56-60. -44.

The vane portion 56 of the vane rotor 52 has an accommodation hole 62 that extends in the rotation axis direction and opens to the bottom 22 side of the shoe housing 18. A lock pin 64 is accommodated in the accommodation hole 62 so as to be capable of reciprocating in the rotation axis direction.
The lock pin 64 includes a cylindrical portion 66 that can slide on the inner wall of the accommodation hole 62, and a fitting portion 68 that is located on the bottom 22 side with respect to the cylindrical portion 66 and has an outer diameter smaller than that of the cylindrical portion 66. Yes. A spring 72 is disposed in the cylindrical portion 66. One end of the spring 72 is locked to the cylindrical portion 66, and the other end is locked to the sprocket 30. The lock pin 64 is urged toward the bottom 22 side of the shoe housing 18 by a spring 72.

When the vane rotor 52 is positioned at the engine start optimum position, the lock pin 64 can fit the fitting portion 68 into the fitting recess 46 provided on the inner wall of the bottom portion 22 of the shoe housing 18. When the fitting portion 68 is fitted into the fitting recess 46, the lock pin 64 regulates the relative rotation of the vane rotor 52 with respect to the housing 16 at the engine start optimum position, and the phase of the camshaft 4 is predetermined engine start. Regulate with the optimal phase. In the first embodiment, the optimum engine start position is set to the most retarded position of the vane rotor 52, and the fitting recess 46 corresponds to the fitting portion 68 of the lock pin 64 when the vane rotor 52 is located at the most retarded position. It is formed to do.
Hereinafter, restricting relative rotation of the vane rotor 52 with respect to the housing 16 is referred to as “relative rotation restriction”.

The cylindrical portion 66 of the lock pin 64 has a flange portion 70 that protrudes radially outward on the sprocket 30 side. A first restriction release chamber 48 is formed on the bottom portion 22 side with respect to the flange portion 70. The first restriction release chamber 48 communicates with the advance hydraulic chamber 34 via a passage 49.
A second restriction release chamber 50 is formed on the bottom 22 side of the lock pin 64 with respect to the fitting portion 68. The second restriction release chamber 50 communicates with the retard hydraulic chamber 40 via a passage 51.

  The pressure of the hydraulic oil supplied to the first restriction release chamber 48 via the advance hydraulic chamber 34 and the pressure of the hydraulic oil supplied to the second restriction release chamber 50 via the retard hydraulic chamber 40 are The fitting portion 68 acts in the direction of coming out of the fitting recess 46. That is, whether or not the vane rotor 52 is held at the engine start optimum position by the lock pin 64 depends on the urging force of the spring 72 and the pressure of the hydraulic oil supplied to the first restriction release chamber 48 and the second restriction release chamber 50. It is determined by the balance with the power.

The advance hydraulic chambers 34 to 38 communicate with the advance oil passage 82 via the advance oil passage 80 of the vane rotor 52 and the camshaft 4. On the other hand, the retard hydraulic chambers 40 to 44 communicate with the retard oil passage 86 via the retard oil passage 84 of the vane rotor 52 and the camshaft 4.
The oil pump 78 pumps up the hydraulic oil from the oil tank 79, discharges the hydraulic oil into the advance oil passage 82 or the retard oil passage 86 according to the operation position of the hydraulic control valve 88, and advances the advance hydraulic chambers 34 to 38 or the delay oil chamber 86. Hydraulic fluid is supplied to the angular hydraulic chambers 40-44.

  The hydraulic control valve 88 is a 5-port electromagnetic valve having a solenoid 90 and a spool 92. The spool 92 has an advance position that connects the oil pump 78 and each advance hydraulic chamber 34 to 38, a retard position that connects the oil pump 78 and each retard hydraulic chamber 40 to 44, and the oil pump 78. It operates to a holding position that cuts off the connection between each advance hydraulic chamber 34-38 and each retard hydraulic chamber 40-44. When the solenoid 90 is not energized, the spool 94 is urged by the springs 94 and 96 to operate in the holding position. On the other hand, when the solenoid 90 is energized, the spool 92 resists the urging force of the springs 94 and 96. Operates to the retard position. The pressure of the hydraulic oil supplied to each oil passage by the hydraulic control valve 88 can be continuously changed by duty ratio control of the current applied to the solenoid 90. This duty ratio control is performed by the electronic control unit 102.

The relief valve 98 is a pilot-operated type that operates by the pilot pressure from the pilot pressure control valve 100, and the pressure of the hydraulic oil flowing from the oil pump 78 to the hydraulic control valve 88 can be adjusted to a predetermined high pressure and low pressure. is there.
The pilot pressure control valve 100 is a high pressure pilot pressure for setting the set pressure of the relief valve 98 to the high pressure, and a low pressure pilot pressure for setting the set pressure of the relief valve 98 to the low pressure. Can be output.

  The electronic control unit 102 includes a microcomputer having a CPU, a ROM, a RAM, and the like (not shown). The electronic control unit 102 includes a crank angle sensor 104 that detects the rotation angle of the crankshaft 2, a cam angle sensor 106 that detects the rotation angle of the camshaft 4, and the pressure of hydraulic fluid flowing into the hydraulic control valve 88 (hereinafter, “ The pressure sensor 108 as “pressure detecting means” for detecting the inflow pressure ”) and various sensors (not shown) for detecting the driving state of the vehicle are electrically connected. The driving state of the vehicle includes, for example, engine speed, engine output torque, engine coolant temperature, and the like. The electronic control unit 102 controls the operation of the hydraulic control valve 88 and the pilot pressure control valve 100 in accordance with a predetermined control program recorded in the ROM based on the electrical signal transmitted from each sensor.

  Specifically, the electronic control unit 102 determines whether or not the relative rotation by the lock pin 64 is being restricted. For example, first, the electronic control unit 102 calculates the rotational phase of the camshaft 4 with respect to the crankshaft 2 based on the crank angle and the cam angle. Subsequently, the electronic control unit 102 determines whether or not the vane rotor 52 is located at the most retarded position based on the calculated rotation phase. If this determination is positive, the electronic control unit 102 determines that relative rotation by the lock pin 64 is being restricted. If the determination is negative, the electronic control unit 102 determines that the relative rotation by the lock pin 64 is not being controlled.

  Further, the electronic control unit 102 determines whether or not there is a command to change the opening / closing timing of the intake valve 9, that is, whether or not there is a start request for the valve timing adjusting device 14. For example, first, the electronic control unit 102 calculates the rotational phase of the camshaft 4 with respect to the crankshaft 2 based on the crank angle and the cam angle. Subsequently, the electronic control unit 102 calculates a target rotation phase of the camshaft 4 with respect to the crankshaft 2 based on the driving conditions of the vehicle. Subsequently, the electronic control unit 102 determines whether or not the calculated rotation phase of the camshaft 4 is different from the target rotation phase. If this determination is affirmative, the electronic control unit 102 determines that there is a request for starting the valve timing adjusting device 14. If the determination is negative, the electronic control unit 102 determines that there is no activation request for the valve timing adjustment device 14.

Further, the electronic control unit 102 calculates a target duty ratio of a current applied to the solenoid 90 in order to set the rotation phase of the camshaft 4 as the target rotation phase. The electronic control unit 102 applies the current of the calculated target duty ratio to the solenoid 90 to adjust the position of the spool 92 of the hydraulic control valve 88, and supplies hydraulic oil having a pressure corresponding to the target duty ratio to the advance hydraulic chamber. 34 or the retard angle hydraulic chamber 40 is executed to perform opening / closing timing adjustment control for rotating the vane rotor 52 relative to the housing 16 toward the advance side or the retard side.
The electronic control device 102 determines whether or not the relative rotation restriction has not been released when a predetermined time has elapsed since the opening / closing timing adjustment control was started during the relative rotation restriction. In the first embodiment, “when the opening / closing timing adjustment control is started” is when it is detected that the target rotation phase of the camshaft 4 has been changed.

  For example, first, the electronic control unit 102 calculates and stores the rotation phase of the camshaft 4 (hereinafter referred to as “initial rotation phase”) when the opening / closing timing adjustment control is started during the relative rotation restriction. Subsequently, the electronic control unit 102 calculates the rotation phase of the camshaft 4 (hereinafter referred to as “rotation phase when a predetermined time has elapsed”) when a predetermined time has elapsed since the start of the opening / closing timing adjustment control. Subsequently, the electronic control unit 102 determines that the difference between the initial rotation phase and the rotation phase when a predetermined time has elapsed corresponds to a circumferential clearance between the fitting portion 68 of the lock pin 64 and the fitting recess 46 of the shoe housing 18. It is determined whether the angle is equal to or smaller than the angle. If this determination is positive, the electronic control unit 102 determines that the relative rotation restriction has not been released. When the determination is negative, the electronic control unit 102 determines that the relative rotation restriction is released.

If the electronic control device 102 determines that the relative rotation restriction has not been released when a predetermined time has elapsed since the start of the opening / closing timing adjustment control during the relative restriction, the inflow pressure falls within a predetermined restriction releaseable pressure range. It is determined whether or not the upper limit value is exceeded, that is, whether or not the inflow pressure is within the regulation release failure occurrence pressure range. The restriction release failure generation pressure region is a pressure region where a relative rotation restriction release failure occurs due to the inflow pressure being too high, and is experimentally obtained in advance, for example.
Further, when the electronic control unit 102 determines that the inflow pressure is within the regulation release failure occurrence pressure range (the inflow pressure exceeds the upper limit value of the restriction releaseable pressure range), the electronic control unit 102 controls the pilot pressure control valve 100 so that the inflow pressure decreases. By performing the control, the forced restriction release control for reducing the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38 is executed.
Further, the electronic control unit 102 determines that the relative rotation restriction is released when the rotational phase of the camshaft 4 changes after the start of the forced restriction release control, and sets the inflow pressure to a value before the start of the forced restriction release control. return.

Next, the operation of the valve timing adjustment system 12 will be described.
When the engine 1 is stopped, the fitting portion 68 of the lock pin 64 is fitted into the fitting recess 46 of the shoe housing 18 and is in a relative rotation restricted state.
Immediately after the engine 1 is started, sufficient hydraulic oil cannot be supplied from the oil pump 78 to each hydraulic chamber. For this reason, the relative rotation restriction by the lock pin 64 is maintained, and the rotational phase of the camshaft 4 with respect to the crankshaft 2 is held at the most retarded position. Thereby, until the hydraulic oil is supplied to the hydraulic chambers, the generation of a hitting sound due to the collision between the shoe housing 18 and the vane rotor 52 due to the pulsating torque of the crankshaft 2 is suppressed.

  When the opening / closing timing adjustment control is started during the relative rotation restriction after the engine is started and the vane rotor 52 is advanced, the electronic control unit 102 operates the hydraulic control valve 88 to the advanced position. As a result, the hydraulic control valve 88 connects the oil pump 78 and the advance oil passage 82, and the hydraulic oil flowing into the hydraulic control valve 88 from the oil pump 78 passes through the advance oil passages 80 and 82, and advances hydraulic pressure. It is supplied to the chambers 34 to 38 and the first restriction release chamber 48. The pressure of the hydraulic oil in the first restriction release chamber 48 acts on the lock pin 64, and an axial force is generated in a direction in which the lock pin 64 is removed from the fitting recess 46. Further, the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38 acts on the vane portions 56 to 60, and torque that urges the vane rotor 52 in the advance direction is generated. Accordingly, the relative rotation restriction is released, and the vane rotor 52 is rotated in the advance direction with respect to the housing 16.

  Here, in order for the lock pin 64 to come out of the fitting recess 46, it is necessary to increase the pressure of the hydraulic oil in the first restriction release chamber 48 to a level against the urging force of the spring 72. This increase in pressure takes time, and as a result, it takes time until the relative rotation restriction is released. As shown in FIG. 4, the longer the inflow pressure P of the oil pump 78 is higher than the predetermined value P1 and the lower the predetermined value P2, the longer it takes to release the relative rotation restriction (regulation release time) Tr. Become. Here, a region A in FIG. 4 is a “regulation release failure occurrence pressure region”, and a region B is a “regulation release possible pressure region”. The predetermined value P1 is the “upper limit value of the restriction releaseable pressure range”, and the predetermined value P2 is the “lower limit value of the restriction releaseable pressure range”.

  Therefore, the advance angle closer to the oil pump 78 than the first restriction release chamber 48 before the hydraulic pressure in the first restriction release chamber 48 is sufficiently increased after the opening / closing timing adjustment control is started during the relative rotation restriction. The pressure of the hydraulic oil in the hydraulic chambers 34 to 38 is increased, and the vane rotor 52 is advanced in the radial clearance between the lock pin 64 and the fitting recess 46 while the lock pin 64 is fitted in the fitting recess 46. May rotate relative to Therefore, as shown in FIG. 5, a situation occurs in which the lock pin 64 is sandwiched between the vane rotor 52 and the shoe housing 18 in the circumferential direction. Conventionally, in such a situation, there has been a problem that the relative rotation restriction cannot be released and the rotational phase of the camshaft 4 cannot be changed.

  In the first embodiment, when the above situation occurs, the electronic control device 102 forcibly releases the relative rotation lock by executing the forced restriction release control. Hereinafter, the control operation of the electronic control unit 102 will be described with reference to FIG. The process shown in FIG. 6 is a flowchart showing a process flow related to the control operation of the electronic control apparatus 102, and is repeatedly executed after the engine is started, for example.

  When the processing of FIG. 6 is started, first, in step S101 (hereinafter, “step” is omitted, and simply indicated by “S”), the electronic control unit 102 detects the vehicle driving condition, that is, each sensor detects. Read the detected value. After S101, the process proceeds to S102.

  In S102, the electronic control unit 102 determines whether or not relative rotation is being restricted. If the determination in S102 is affirmative (S102: YES), the process proceeds to S103. If the determination in S102 is negative (S102: NO), the process returns to S101.

  In S <b> 103, the electronic control unit 102 determines whether there is a command to change the opening / closing timing of the intake valve 9, that is, whether there is an activation request for the valve timing adjusting device 14. If the determination in S103 is affirmative (S103: YES), the process proceeds to S104. If the determination in S103 is negative (S103: NO), the process returns to S101.

  In S104, the electronic control unit 102 calculates the target duty ratio of the current applied to the solenoid 90 in order to set the rotation phase of the camshaft 4 as the target rotation phase. After S104, the process proceeds to S105.

  In S105, the electronic control unit 102 adjusts the position of the spool 92 of the hydraulic control valve 88 by applying the current of the target duty ratio calculated in S104 to the solenoid 90, and supplies hydraulic oil having a pressure corresponding to the target duty ratio. By supplying to the advance hydraulic chamber 34 or the retard hydraulic chamber 40, the opening / closing timing adjustment control for rotating the vane rotor 52 relative to the housing 16 toward the advance side or the retard side is executed. After S105, the process proceeds to S106.

  In S <b> 106, the electronic control unit 102 determines whether or not the relative rotation restriction has not been released when a predetermined time has elapsed since the opening / closing timing adjustment control was started. If the determination in S106 is affirmative (S106: YES), the process proceeds to S107. If the determination in S106 is negative (S106: NO), the process exits the series of routines shown in FIG.

  In S107, the electronic control unit 102 determines whether or not the inflow pressure exceeds the upper limit value (predetermined value P1 in FIG. 4) of the deregulatable pressure range, that is, the inflow pressure is within the deregulation failure occurrence pressure range (region A in FIG. 4). ) Is determined. If the determination in S107 is affirmative (S107: YES), the process proceeds to S108. If the determination in S107 is negative (S107: NO), the process exits the series of routines shown in FIG.

  In S108, the electronic control unit 102 controls the pilot pressure control valve 100, operates the relief valve 98, and changes the inflow pressure to a predetermined low pressure, thereby changing the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38. Forced restriction release control to be reduced is executed. After S108, the process proceeds to S109.

In S109, the electronic control unit 102 calculates the rotational phase of the camshaft 4, and determines whether or not the calculated rotational phase is the same as the initial rotational phase, that is, whether or not the relative rotation restriction has not been released. If the determination in S109 is affirmative (S109: YES), the process proceeds to S110. If the determination in S109 is negative (S109: NO), the process repeats S109.
In S110, the electronic control unit 102 returns the inflow pressure to the value before the relief valve 98 is operated in S108. After S110, the process exits the series of routines shown in FIG.

  7, 8, and 10 show the target rotation phase PHt of the camshaft 4 and the actual rotation phase PH of the camshaft 4 (hereinafter referred to as “actual rotation phase”) when the opening / closing timing adjustment control is started during the relative rotation restriction. Is a time chart showing changes in the inflow pressure command value Pt and the actual inflow pressure P (hereinafter referred to as “actual inflow pressure”). The time charts shown in FIGS. 7 and 8 are those of this embodiment, and the time chart shown in FIG. 10 is conventional.

The time chart shown in FIG. 7 is a case where the relative rotation restriction is released when a predetermined time has elapsed since the opening / closing timing adjustment control was started during the relative rotation restriction.
From time t0 to time t1 in FIG. 7, the target rotational phase PHt is 0, that is, the most retarded position. During this time, the electronic control unit 102 affirms the determination in S102 of FIG.
The time t1 in FIG. 7 is the time when the target rotation phase PHt is changed. At this time, the electronic control unit 102 affirms the determination in S103 of FIG.
Time T1 from time t1 to time t2 in FIG. 7 corresponds to the predetermined time. At the time t2 when the predetermined time T1 has elapsed from the time t1, the actual rotation phase PH has changed from the time t1. At this time, the electronic control unit 102 denies the determination of S106 in FIG.

The time chart shown in FIG. 8 is a case where the relative rotation restriction is not released when a predetermined time has elapsed since the opening / closing timing adjustment control was started during the relative rotation restriction.
The time t10 and the time t11 in FIG. 8 are the same as the time t0 and the time t1 in FIG.
At time t12 when the predetermined time T1 has elapsed from time t11 in FIG. 8, the actual rotational phase PH has not changed from time t11. At this time, the electronic control unit 102 affirms the determination of S106 in FIG. 6 and executes the process of S107 in FIG. At time t12 in FIG. 8, the inflow pressure command value Pt is changed to a command value L corresponding to a predetermined low pressure, and the actual inflow pressure P gradually decreases immediately thereafter.

At time t <b> 13 in FIG. 8, the hydraulic oil pressure in the advance hydraulic chambers 34 to 38 is reduced, the torque in the advance direction of the vane rotor 52 is reduced, and so-called scouring where the lock pin 64 is fixed is eliminated. . The actual rotation phase PH starts to change immediately after this time t13.
At time t14 in FIG. 8, the electronic control apparatus 102 affirms the determination in S108 in FIG. 6 and executes the process in S109 in FIG. At time t14 in FIG. 8, the inflow pressure command value Pt is changed to a command value H corresponding to a predetermined high pressure. Thereafter, the actual rotational phase PH becomes a predetermined value, and the actual inflow pressure P returns to the level at the time t11.

  On the other hand, as shown in FIG. 10, conventionally, when the relative rotation restriction between the housing and the vane rotor cannot be released after the opening / closing timing adjustment control is started at time t20 during the relative rotation restriction, The actual rotation phase PH does not change, and the opening / closing timing of the intake valve cannot be adjusted.

  As described above, the electronic control unit 102 of the valve timing adjustment system 12 according to the first embodiment performs a relative operation when a predetermined time elapses after the opening / closing timing adjustment control starts during the relative rotation restriction by the lock pin 64. A restriction unreleased determination is performed to determine whether or not the rotation restriction is unreleased. Further, when the restriction non-release determination is affirmed, the electronic control device 102 executes a first pressure determination that determines whether or not the inflow pressure exceeds the upper limit value of the restriction releaseable pressure range. Further, when the first pressure determination is affirmed, the electronic control unit 102 operates the relief valve 98 so that the inflow pressure becomes a predetermined low pressure, thereby adjusting the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38. Forced restriction release control to be reduced is executed.

  Therefore, when the opening / closing timing adjustment control is started during the relative rotation restriction by the lock pin 64, the hydraulic oil in the advance hydraulic chambers 34 to 38 is discharged before the hydraulic oil pressure in the first restriction release chamber 48 is sufficiently increased. When the lock pin 64 is pressed against the inner wall of the fitting recess 46 of the housing 16 due to an increase in pressure, the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38 is reduced after a predetermined time. As a result, the torque acting on the vane rotor 52 is reduced, and the force pressing the lock pin 64 against the inner wall of the fitting recess 46 of the housing 16 is reduced. Therefore, the lock pin 64 can be easily removed from the fitting recess 46 of the housing 16, and the relative rotation restriction between the housing 16 and the vane rotor 52 can be released. Therefore, it is possible to suppress the restriction release failure of the relative rotation between the housing 16 and the vane rotor 52.

In the first embodiment, the relief valve 98 is a pilot operated type that is operated by the pilot pressure from the pilot pressure control valve 100, and the inflow pressure can be adjusted to a predetermined high pressure and low pressure.
Therefore, the relief valve 98 can employ a simple structure capable of adjusting the inflow pressure in two stages.

  In the first embodiment, the electronic control unit 102 calculates the rotation phase of the camshaft 4 when the opening / closing timing adjustment control is started during the relative rotation restriction, that is, the initial rotation phase. Further, the electronic control device 102 calculates the rotation phase of the camshaft 4, that is, the rotation phase when the predetermined time has elapsed when a predetermined time has elapsed since the start of the opening / closing timing adjustment control. Further, the electronic control unit 102 determines that the difference between the initial rotation phase and the rotation phase when a predetermined time has elapsed corresponds to the circumferential clearance between the fitting portion 68 of the lock pin 64 and the fitting recess 46 of the shoe housing 18. It is determined whether or not: If this determination is positive, the electronic control unit 102 determines that the relative rotation restriction has not been released. Therefore, it is possible to determine whether the relative rotation restriction is not released based on the crank angle and the cam angle.

In the first embodiment, the electronic control unit 102 releases the relative rotation restriction when the rotational phase of the crankshaft 2 and the camshaft 4 changes after the relief valve 98 is operated so that the inflow pressure changes. The inflow pressure is returned to the value before operating the relief valve 98.
Thereby, opening / closing timing control can be restarted quickly.

(Second Embodiment)
The valve timing adjustment system according to the second embodiment is different from the first embodiment in the control operation of the electronic control device. The electronic control device according to the second embodiment functions as “opening / closing timing adjustment control means”, “unregulated release determination means”, “forced restriction release control means”, and “first pressure determination means” in the first embodiment. However, it also functions as “second pressure determining means”.
Hereinafter, the control operation of the electronic control device according to the second embodiment will be described with reference to FIG. The process shown in FIG. 9 is a flowchart showing a process flow relating to the control operation of the electronic control apparatus according to the second embodiment, and is repeatedly executed after the engine is started, for example. In addition, the processing content of S101-S110 of FIG. 9 is the same as that of FIG.

If the determination in S107 of FIG. 9 is negative (S107: NO), the process proceeds to S201.
In S201, the electronic control unit determines whether or not the inflow pressure is lower than a lower limit value of the restriction releaseable pressure range. The pressure range below the lower limit value of the restriction releaseable pressure range is a pressure range in which the relative rotation restriction release failure occurs due to the inflow pressure being too low, and is experimentally obtained in advance, for example. If the determination in S201 is affirmative (S201: YES), the process proceeds to S202. If the determination in S201 is negative (S201: NO), the process proceeds to S205.

  In S202, the electronic control unit controls the pilot pressure control valve 100, operates the relief valve 98, and changes the inflow pressure to a predetermined high pressure, thereby increasing the pressure of the hydraulic oil in the first restriction release chamber 48. Performs forced restriction release control. After S202, the process proceeds to S203.

  In S203, the electronic control unit calculates the rotational phase of the camshaft 4, and determines whether or not the calculated rotational phase is the same as the target rotational phase. If the determination in S203 is affirmative (S203: YES), the process proceeds to S204. If the determination in S203 is negative (S203: NO), the process repeats S203.

In S204, the electronic control unit returns the inflow pressure to the value before the relief valve 98 is operated in S202. After S204, the process exits the series of routines shown in FIG.
In S205, the electronic control unit determines that the lock pin 64 or the hydraulic control valve 88 is abnormal, and lights a warning lamp (not shown) to notify the driver of the abnormality. After S205, the process exits a series of routines shown in FIG.

  As described above, the electronic control device of the valve timing adjustment system according to the second embodiment controls the relative rotation when a predetermined time elapses after the opening / closing timing adjustment control starts during the relative rotation restriction by the lock pin 64. Is not released, the first pressure determination is performed to determine whether the inflow pressure exceeds the upper limit value of the deregulatable pressure range, that is, whether the inflow pressure is within a predetermined deregulation failure occurrence pressure range. To do. In addition, when the first pressure determination is affirmed, the electronic control device operates the relief valve 98 so that the inflow pressure becomes a low pressure.

  Accordingly, when the opening / closing timing adjustment control is started while the relative rotation is restricted by the lock pin 64, if the lock pin 64 is pressed against the inner wall of the fitting recess 46 of the housing 16 due to the inflow pressure being too high, a predetermined time is reached. Later, the pressure of hydraulic oil in the advance hydraulic chambers 34 to 38 is reduced. As a result, the torque acting on the vane rotor 52 is reduced, and the force pressing the lock pin 64 against the inner wall of the fitting recess 46 of the housing 16 is reduced. Therefore, the lock pin 64 can be easily removed from the fitting recess 46 of the housing 16, and the relative rotation restriction between the housing 16 and the vane rotor 52 can be released. Therefore, it is possible to suppress the restriction release failure of the relative rotation between the housing 16 and the vane rotor 52.

  In the second embodiment, when the first pressure determination unit is denied, the electronic control unit performs a second pressure determination that determines whether or not the inflow pressure is lower than a lower limit value of a predetermined deregulatable pressure range. Run. Further, when the second pressure determination means is fixed, the electronic control device operates the relief valve 98 so that the inflow pressure becomes the high pressure.

  Therefore, when the opening / closing timing adjustment control is started while the relative rotation is restricted by the lock pin 64, when the lock pin 64 does not come out of the fitting recess 46 of the housing 16 due to the inflow pressure being too low, after a predetermined time. The pressure of the hydraulic oil in the first restriction release chamber 48 is increased. Thereby, the axial force in the direction in which the lock pin 64 comes out of the fitting recess 46 of the housing 16 is increased by the pressure of the hydraulic oil in the first restriction release chamber 48. Therefore, the lock pin 64 can be easily removed from the fitting recess 46 of the housing 16, and the relative rotation restriction between the housing 16 and the vane rotor 52 can be released. Therefore, it is possible to suppress the restriction release failure of the relative rotation between the housing 16 and the vane rotor 52.

  In the second embodiment, when both the first pressure determination and the second pressure determination are denied, the electronic control unit determines that the lock pin 64 or the hydraulic control valve 88 is abnormal and turns on the warning lamp. Inform the driver of the above abnormality. Therefore, the driver can respond immediately.

(Third embodiment)
The valve timing adjustment system according to the third embodiment is different from the first embodiment in the control operation of the electronic control device. The electronic control device according to the third embodiment can continuously increase or decrease the pilot pressure of the pilot pressure control valve 100. Accordingly, the relief valve 98 can continuously adjust the inflow pressure.
In addition, the electronic control device is configured such that when the predetermined rotation time has elapsed after the opening / closing timing adjustment control is started during the relative rotation restriction by the lock pin 64, the inflow pressure is a pressure that can be released when the relative rotation restriction is not released. A first pressure determination is performed to determine whether or not the upper limit value of the region is exceeded, that is, whether or not the inflow pressure is within a predetermined deregulation failure occurrence pressure region. In addition, when the first pressure determination is affirmed, the electronic control device operates the relief valve 98 so that the inflow pressure is within the deregulatable pressure range.

  Therefore, according to the valve timing adjustment system according to the third embodiment, when the opening / closing timing adjustment control is started during the relative rotation restriction by the lock pin 64, the lock pin 64 of the housing 16 is caused by the inflow pressure being too high. When pressed against the inner wall of the fitting recess 46, the pressure of the hydraulic oil in the advance hydraulic chambers 34 to 38 is reduced after a predetermined time. As a result, the torque acting on the vane rotor 52 is reduced, and the force pressing the lock pin 64 against the inner wall of the fitting recess 46 of the housing 16 is reduced. Therefore, the lock pin 64 can be easily removed from the fitting recess 46 of the housing 16, and the relative rotation restriction between the housing 16 and the vane rotor 52 can be released. Therefore, it is possible to suppress the restriction release failure of the relative rotation between the housing 16 and the vane rotor 52.

(Other embodiments)
In the above-described embodiment, “when the opening / closing timing adjustment control is started” is when it is detected that the target rotation phase of the camshaft 4 has been changed. On the other hand, in another embodiment of the present invention, “when opening / closing timing adjustment control is started” may be, for example, when the electronic control device starts operating the hydraulic control valve.

In another embodiment of the present invention, the hydraulic control valve and the relief valve may be a direct acting type or a pilot type.
In another embodiment of the present invention, the pressure detection means is not limited to the pressure sensor that directly detects the inflow pressure, and calculates the inflow pressure based on other values such as engine oil pressure, oil temperature, water temperature, and the like. It may be.
In another embodiment of the present invention, the valve timing adjustment system may be applied to an exhaust valve.
In another embodiment of the present invention, the vane rotor may rotate integrally with the crankshaft, and the housing may rotate integrally with the camshaft.

In another embodiment of the present invention, a gear that can rotate integrally with the housing and is driven by the crankshaft via the chain may be provided in the shoe housing. Accordingly, a cover for closing the opening end of the shoe housing may be provided instead of the sprocket.
In another embodiment of the present invention, what is wound around the gear of the clan shaft or the gear of each camshaft is not limited to the chain, and may be another transmission member such as a belt.
In another embodiment of the present invention, the number of vane portions of the vane rotor and the shoe portions of the housing may be other than three.
In other embodiments of the present invention, fluids other than hydraulic oil may be used as the hydraulic fluid.

  The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Crankshaft (drive shaft)
4 ... Camshaft (driven shaft)
DESCRIPTION OF SYMBOLS 9 ... Intake valve 10 ... Exhaust valve 12 ... Valve timing adjustment system 16 ... Housing 18 ... Shoe housing (housing)
30 ・ ・ ・ Sprocket (housing)
34 ・ ・ ・ Advance hydraulic chamber 40 ・ ・ ・ Delay hydraulic chamber 48 ・ ・ ・ First restriction release chamber (regulation release chamber)
52 ... Vane rotor 54 ... Boss part 56, 58, 60 ... Vane part 64 ... Lock pin (regulation member)
78 ... Oil pump 88 ... Hydraulic control valve (switching valve)
98 ・ ・ ・ Relief valve (pressure regulating valve)
102... Electronic control device (opening / closing timing adjustment control means, restriction non-release determination means, forced restriction release control means, first pressure determination means)
T1 ... Predetermined time

Claims (8)

A valve timing adjustment system that adjusts the opening / closing timing of an intake valve or an exhaust valve that is driven to open and close by changing the rotational phase of a drive shaft and a driven shaft of an engine,
A housing that rotates integrally with one of the drive shaft and the driven shaft;
The drive shaft and the driven shaft are integrally formed from a boss portion provided in the housing and a vane portion that partitions the interior of the housing into an advance chamber and a retard chamber, and is rotatable relative to the housing. A vane rotor that rotates integrally with the other of
The vane rotor is slidably supported, and the relative rotation between the housing and the vane rotor can be restricted by engaging with the housing, and the restriction release chamber communicated with the advance chamber or the retard chamber. A regulating member that receives the pressure of the working fluid and releases the relative rotation regulation by moving away from the housing;
A pump capable of supplying a working fluid to the advance chamber, the retard chamber, and the deregulation chamber;
A switch that is provided between the pump and the advance chamber and the retard chamber and that operates to connect the pump and the advance chamber and to connect the pump and the retard chamber. A valve,
A pressure adjusting valve capable of adjusting an inflow pressure of the working fluid flowing into the switching valve;
Pressure detecting means for detecting the inflow pressure;
When there is a command to change the opening / closing timing, the vane rotor is advanced or retarded with respect to the housing by operating the switching valve so that the working fluid is supplied to the advance chamber or the retard chamber. Opening and closing timing adjustment control means for relative rotation to the side,
Unregulated determination means for determining whether or not the relative rotation restriction is not released when a predetermined time has elapsed after the opening / closing timing adjustment control is started during the relative rotation restriction by the restriction member;
A first pressure determination unit that determines whether or not the inflow pressure exceeds an upper limit value of a predetermined deregulatable pressure range when the unregulated determination unit determines that the relative rotation restriction is not released;
When the first pressure determining means determines that the inflow pressure exceeds the upper limit value of the deregulatable pressure region, the state where the inflow port of the switching valve and the advance chamber or the retard chamber are in communication with each other is maintained. while, by the inflow pressure actuates the pressure control valve to decrease, forcing deregulation reducing the pressure of at least one of the working fluid in the advance chamber and the retard chamber in communication with said inlet port Control means;
A valve timing adjustment system comprising: The pressure adjusting valve is capable of adjusting the inflow pressure to a predetermined high pressure and low pressure,
When the first pressure determination unit determines that the inflow pressure exceeds the upper limit value of the deregulatable pressure range, the forcible deregulation control unit controls the pressure adjustment valve so that the inflow pressure becomes the low pressure. The valve timing adjustment system according to claim 1, wherein the valve timing adjustment system is operated. When the first pressure determination means determines that the inflow pressure is equal to or lower than the upper limit value of the deregulatable pressure range, the first pressure determination unit determines whether the inflow pressure is below a lower limit value of the deregulatable pressure range. 2 further comprises pressure determining means,
When the second pressure determination means determines that the inflow pressure falls below a lower limit value of the deregulatable pressure range, the forced restriction release control means operates the pressure adjustment valve so that the inflow pressure increases. The valve timing adjustment system according to claim 1, wherein the pressure of the working fluid in the restriction release chamber is increased by the control. The pressure adjusting valve is capable of adjusting the inflow pressure to a predetermined high pressure and low pressure,
The forced restriction release control means is configured to control the pressure regulating valve so that the inflow pressure becomes the low pressure when the first pressure determination means determines that the inflow pressure exceeds an upper limit value of the restriction releaseable pressure range. And when the second pressure determining means determines that the inflow pressure falls below a lower limit value of the deregulatable pressure range, the pressure adjusting valve is operated so that the inflow pressure becomes the high pressure. The valve timing adjusting system according to claim 3.   When the first pressure determination unit determines that the inflow pressure exceeds an upper limit value of the deregulatable pressure range, the forcible deregulation control unit is configured so that the inflow pressure is within the deregulatable pressure range. 2. The valve timing adjustment system according to claim 1, wherein the pressure of the working fluid of at least one of the advance chamber and the retard chamber is lowered by operating an adjustment valve.   The forced restriction release control means determines that the first pressure determination means determines that the inflow pressure is equal to or lower than an upper limit value of the restriction releaseable pressure range, and the inflow pressure is a lower limit value of the restriction releaseable pressure range. 5. The valve timing adjustment system according to claim 3, wherein when the second pressure determination unit determines that the above is true, the restriction member or the switching valve is determined to be abnormal. The regulating member forms a circumferential clearance between the housing and the housing during relative rotation regulation,
The unregulated release determining means includes a rotation phase of the driven shaft with respect to the drive shaft when opening / closing timing adjustment control is started during relative rotation restriction, and the driven shaft with respect to the drive shaft when the predetermined time has elapsed. The relative rotation restriction is determined to be unreleased when the difference from the rotational phase is equal to or less than a predetermined angle corresponding to the circumferential clearance. The valve timing adjustment system described.   The forced restriction release control means determines that the relative rotation restriction is released when the rotational phase of the driven shaft with respect to the drive shaft changes after the pressure regulating valve is operated so that the inflow pressure decreases or increases. The valve timing adjustment system according to any one of claims 1 to 7, wherein the inflow pressure is returned to a value immediately before the pressure adjustment valve is operated.

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