JP5895999B2 - Control device for variable valve gear - Google Patents

Description

  The present invention is a control device for a variable valve operating apparatus for an internal combustion engine that includes a hydraulic phase change mechanism that changes valve timing and a phase lock mechanism that fixes valve timing to a specific phase. The present invention relates to a control device for a variable valve gear that controls operation.

  The control device for the variable valve operating device described in Patent Document 1 fixes the valve timing to a specific phase by the phase fixing mechanism when the temperature of the hydraulic oil of the phase changing mechanism is low from the viewpoint of stability of feedback control of the valve timing. . That is, when the temperature of the hydraulic fluid of the phase change mechanism is low, control for limiting the operation of the phase change mechanism is performed.

Japanese Patent Laid-Open No. 11-210424

  Assuming that the temperature of the hydraulic oil and the rotational speed of the internal combustion engine are the same, the operating speed of the phase change mechanism when a high-viscosity type hydraulic oil is used and the low-viscosity type operation When comparing the operating speed of the phase change mechanism when oil is used, the operating speed of the former is lower than the operating speed of the latter because the resistance of the high-viscosity hydraulic oil is large. That is, the operating speed of the phase change mechanism does not change only under the influence of the temperature of the hydraulic oil, but also changes under the influence of the viscosity due to the difference in the type of hydraulic oil.

  On the other hand, since the control device of the variable valve device of Patent Document 1 uniformly restricts the operation of the phase change mechanism when the temperature of the hydraulic oil is low, when a low-viscosity type hydraulic oil is used, That is, even when the influence of the viscosity of the hydraulic oil on the operating speed of the phase change mechanism is predicted to be small, it is not allowed to change the valve timing.

  This state is a state in which the changeable range of the valve timing is excessively limited with respect to the changeable range corresponding to the engine operating state, although the valve timing is allowed to change according to the engine operating state. It corresponds to.

  Here, as an example of limiting the operation of the phase change mechanism, an example in which the operation of the phase change mechanism is fixed by the phase fixing mechanism is given as an example, but the operation of the phase change mechanism is limited in consideration of the viscosity of the hydraulic oil. If the control device of the variable valve operating device that performs the control for this is considered, the same problem as described above is considered to occur.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to control a variable valve gear that can secure more situations in which the valve timing can be changed according to the engine operating state. To provide an apparatus.

[1] A control device for a variable valve operating apparatus according to one aspect of the present invention includes a hydraulic phase change mechanism that changes a valve timing and a variable movement of an internal combustion engine that includes a phase locking mechanism that fixes the valve timing to a specific phase. A control device for a valve device, wherein the valve timing is fixed at the specific phase in the variable valve device control device that controls the operation of the phase change mechanism. The operation state of the phase change mechanism that can change the valve timing is set to the phase release state, and the range in which the valve timing can be changed can be changed when the phase change mechanism is in the phase release state. The hydraulic oil temperature of the phase change mechanism is an oil temperature, a period for limiting the changeable range is a limiting period, and the oil temperature is a predetermined temperature range. When the valve timing is advanced with the predetermined oil temperature at a predetermined oil temperature, the operation speed of the phase change mechanism is learned, and the changeable range and the limit are determined according to the learned operation speed of the phase change mechanism. Limit control is performed to change at least one of the periods.
In the control device for a variable valve apparatus, the specific phase is a phase between a most retarded angle phase and a most advanced angle phase, and the specific phase in a range from the most retarded angle phase to the specific phase. A predetermined phase on the more retarded side than the specific phase in the range from the most advanced phase to the specific phase is set as the advanced side limited phase. The range from the specific phase to the retard side limit phase is the retard side limit range, and the range from the specific phase to the advance side limit phase is the advance side limit range, and the changeable range The retard side limit range and the advance side limit range are included, and for each learned operation speed of the phase change mechanism, the size of the retard side limit range is made smaller than the size of the advance side limit range. In the restriction control, the change is possible at the predetermined oil temperature. The range and the retarded side limit range and the advance side limits.

  According to the control device for the variable valve operating apparatus, the limit control is performed according to the operation speed of the phase change mechanism reflecting the difference in the viscosity of the hydraulic oil, so that the operation of the phase change mechanism is performed in a state where the temperature of the hydraulic oil is low. As compared with a configuration that uniformly restricts, it is possible to secure more situations where the valve timing can be changed according to the engine operating state.

  The torque of the camshaft varies in the advance direction and the retard direction. Further, the torque acting in the retard direction is larger than the torque acting in the advance direction. For this reason, when the valve timing is advanced, the resistance applied to the phase change mechanism is larger than when the valve timing is retarded. Thereby, the difference in the operation speed due to the difference in the viscosity of the hydraulic oil is easier to detect when the valve timing is advanced than when the valve timing is retarded. In the above invention, focusing on this point, the operation speed is learned when the valve timing is advanced. For this reason, the frequency at which the operating speed of the phase change mechanism is appropriately learned increases.

[2] According to one aspect of the control device for the variable valve operating apparatus, when the valve timing starts to change, the operation speed of the phase change mechanism is learned.
In the control device for the variable valve operating system, the valve timing change rate is learned on the basis of the change rate of the valve timing as a reference in accordance with the change rate of the valve timing from this state. Compared with a configuration in which learning is performed with reference to a state in which the change speed of fluctuates, the frequency at which the operation speed of the phase change mechanism is appropriately learned becomes higher.

  [3] According to one aspect of the control device for the variable valve operating device, when the operation state of the phase change mechanism is changed from the phase fixed state to the phase release state according to the engine operating state, the phase change Learn the operating speed of the mechanism.

  In the control device for the variable valve system, the operation speed is learned when the operation state of the phase change mechanism is changed from the phase fixed state to the phase release state according to the engine operation state. Compared with the configuration in which the phase change mechanism is operated, it is possible to reduce the frequency at which the valve timing is changed to one that is not suitable for the engine operating state as the operating speed is learned.

  [4] According to one aspect of the control device for the variable valve operating apparatus, when learning the operation speed of the phase change mechanism, the phase change mechanism is set to a predetermined state as a supply and discharge mode of the hydraulic oil to the phase change mechanism. The gist is to select a supply / discharge mode for driving at an operation speed higher than the operation speed.

[5] According to one aspect of the control device for the variable valve operating apparatus, the gist is to learn the operation speed of the phase change mechanism in consideration of the rotation speed of the internal combustion engine.
In an internal combustion engine that supplies hydraulic oil to the phase change mechanism by the torque of the crankshaft, the operating speed of the phase change mechanism changes according to the rotational speed of the internal combustion engine. In the above invention, since the operation speed of the phase change mechanism is learned in consideration of the rotation speed of the internal combustion engine, the influence of the rotation speed on the learned operation speed can be reduced. For this reason, it is possible to learn the operation speed of the phase change mechanism in which the influence of the viscosity of the hydraulic oil is more appropriately reflected.

According to an embodiment of the control device (6) the variable valve device, before Symbol limit control, the phase changes learned the magnitude of the variable range when the operating speed of the learned the phase change mechanism is small It is made smaller than the size of the changeable range when the operating speed of the mechanism is high .

  According to the control device for the variable valve system, the difference in the viscosity of the hydraulic oil and the difference in the hydraulic oil due to the difference in the components of the hydraulic oil are reflected in the limit control or changeable range. Compared to a configuration that uniformly restricts the operation of the phase change mechanism in a low temperature state, it is possible to secure more situations where the valve timing can be changed according to the engine operating state.

  The higher the oil viscosity, the greater the resistance of the hydraulic oil to the operation of the phase change mechanism, so the time it takes to change the phase change mechanism from the phase release state to the phase fixed state is greater than when the oil viscosity is low. Higher is longer. As a result, for example, when the oil viscosity is high and when the engine stall occurs, the engine may stop without changing the phase change mechanism to the phase fixed state compared to when the oil viscosity is low and when the engine stall occurs. Becomes higher.

In the control device of the variable valve device, it is smaller than the variable range when the operation speed is high in the phase changing mechanism has learned changeable range when the operating speed of the learned the phase change mechanism is small. For this reason, it is possible to reduce the frequency at which the engine is stopped without the phase change mechanism being changed to the phase fixed state.

According to an embodiment of the control device (7) the variable valve device, before Symbol limit control, and learn the size of the retard angle side limit range when the operating speed of the learned the phase change mechanism is small the It is made smaller than the size of the retard side limit range when the operating speed of the phase change mechanism is high .

  The torque of the camshaft varies in the advance direction and the retard direction. Further, the torque acting in the retard direction is larger than the torque acting in the advance direction. For this reason, when the valve timing that is retarded from the specific phase is advanced, the resistance applied to the phase change mechanism is greater than when the valve timing that is advanced from the specific phase is retarded. For this reason, when the valve timing is retarded from the specific phase when engine stall occurs, the engine is stopped without changing the phase change mechanism to the phase fixed state as the difference between the valve timing and the specific phase increases. Is more likely to do.

In the control device of the variable valve device, smaller than the retard side limit range when the operation speed of the phase changing mechanism has learned retard side limit range when the operating speed of the learned the phase change mechanism is small is large you are. For this reason, it is possible to reduce the frequency at which the engine is stopped without the phase change mechanism being changed to the phase fixed state.

According to an embodiment of the control device (8) the variable valve device, before Symbol limit control, the retard side limit range when the operating speed of the learned the phase change mechanism is small and the advance side limits The phase change mechanism that has learned the magnitude of the phase change mechanism is made smaller than the magnitudes of the retard side limit range and the advance side limit range when the operation speed is high .

In the control device of the variable valve device, the retarded angle when the operation speed of the phase changing mechanism has learned retard side limits and the advance side limit range when the operating speed of the learned the phase change mechanism is small is large It is smaller than the side limit range and the advance side limit range. For this reason, it is possible to reduce the frequency at which the engine is stopped without the phase change mechanism being changed to the phase fixed state.

[9] According to one aspect of the control device for the variable valve operating apparatus, in the restriction control, the operation speed of the phase change mechanism that has learned the restriction period when the learned operation speed of the phase change mechanism is small. It is set longer than the limit period when it is larger.

According to this control apparatus for a variable valve device, that in comparison with a structure in which the temperature of the work aggressive media limits the operation of the phase changing mechanism uniformly at a low state, is changed according to the valve timing to the engine operating condition More possible situations can be secured.

In addition, the limited period when the learned operation speed of the phase change mechanism is low is set longer than the restricted period when the learned operation speed of the phase change mechanism is high . For this reason, it is possible to reduce the frequency at which the engine is stopped without the phase change mechanism being changed to the phase fixed state.

The schematic diagram which shows typically the structure of an internal combustion engine provided with this about the control apparatus of the variable valve apparatus of one Embodiment of this invention. Sectional drawing which shows the cross-sectional structure along the radial direction about the valve timing change mechanism of the embodiment. Sectional drawing which shows what expanded | deployed on the plane the cross-sectional structure which follows the AA line of FIG. 2 about the valve timing change mechanism of the embodiment. Sectional drawing which shows what expanded | deployed on the plane the cross-sectional structure which follows the AA line of FIG. 2 about the valve timing change mechanism of the embodiment. The flowchart which shows the procedure about "control at the time of phase cancellation | release" performed by the electronic control apparatus of the embodiment. The timing chart which shows an example of the execution aspect about "control at the time of phase cancellation" performed by the electronic controller of the embodiment. The flowchart which shows the procedure about "operation speed learning control" performed by the electronic control apparatus of the embodiment. The map which shows the relationship between the learning operation speed referred in the same control, and the changeable range about "operation speed learning control" performed by the electronic control apparatus of the embodiment. The timing chart which shows an example of the execution aspect about "operation speed learning control" performed by the electronic control apparatus of the embodiment. The flowchart which shows the procedure of the "control at the time of phase cancellation | release" performed by the electronic controller about the control apparatus of the variable valve apparatus as other embodiment of this invention.

The configuration of the internal combustion engine 1 will be described with reference to FIG.
The internal combustion engine 1 includes an engine main body 10 that rotates a crankshaft 15 by combustion of an air-fuel mixture, a variable valve operating device 20 that includes each element of a valve operating system, and a hydraulic mechanism 70 that supplies hydraulic oil to the engine main body 10 and the like. And a control device 80 for comprehensively controlling various devices including these devices.

  The engine body 10 includes a cylinder block 11 in which the air-fuel mixture is combusted, a cylinder head 12 provided with a variable valve operating device 20, and an oil pan 13 that stores hydraulic oil supplied to each part of the engine body 10. ing.

  The variable valve system 20 includes an intake valve 21 that opens and closes an intake port of the combustion chamber 14, an exhaust valve 23 that opens and closes an exhaust port of the combustion chamber 14, an intake camshaft 22 that pushes down the intake valve 21, An exhaust camshaft 24 that pushes down the exhaust valve 23 is provided. In addition, a valve timing changing mechanism 30 that changes the rotational phase of the intake camshaft 22 relative to the rotational phase of the crankshaft 15 (hereinafter, “valve timing VT”), and a valve timing fixing mechanism 40 that fixes the valve timing VT, It has.

  The valve timing changing mechanism 30 changes the valve timing VT from the most advanced valve timing (hereinafter “most advanced angle phase VTmax”) to the most retarded valve timing (hereinafter “most delayed angle phase VTmin”). Change between.

  The valve timing fixing mechanism 40 fixes the valve timing VT to a specific valve timing between the most retarded angle phase VTmin and the most advanced angle phase VTmax (hereinafter, “intermediate angle phase VTmdl”). The intermediate angle phase VTmdl corresponds to a “specific phase”.

  As the intermediate angle phase VTmdl, a valve timing VT capable of starting the internal combustion engine 1 in a cold region is set. When comparing the case where the valve timing VT is maintained at the intermediate angle phase VTmdl at the time of engine start and the case where the valve timing VT is maintained at the retarded angle side valve timing VT, the former is better than the latter. High startability.

  The hydraulic mechanism 70 includes an oil pump 71 that discharges hydraulic oil from the oil pan 13, an oil control valve 72 that controls a supply mode and a discharge mode of hydraulic fluid for the valve timing changing mechanism 30, and a valve timing fixing mechanism 40. And an oil switching valve 73 for controlling a supply mode and a discharge mode of the hydraulic oil. In addition, a hydraulic oil passage 74 that supplies the hydraulic oil discharged from the oil pump 71 to each part of the internal combustion engine 1 is provided.

  The hydraulic oil passage 74 connects the advance oil passage 75 that connects the advance chamber 37 of the valve timing changing mechanism 30 and the oil control valve 72, and the retard chamber 38 and the oil control valve 72 of the valve timing change mechanism 30. And a phase lock oil passage 77 that connects the first release chamber 54 and the second release chamber 64 of the valve timing fixing mechanism 40 to the oil switching valve 73.

  The control device 80 includes an electronic control device 81 that performs various arithmetic processes for controlling the internal combustion engine 1, a crank position sensor 82, a cam position sensor 83, a coolant temperature sensor 84, and an accelerator position sensor 85. And various sensors.

  The crank position sensor 82 outputs a signal corresponding to the rotation angle of the crankshaft 15 (hereinafter, “crank angle CA”) to the electronic control unit 81. The cam position sensor 83 outputs a signal corresponding to the rotation angle of the intake camshaft 22 (hereinafter “cam angle DA”) to the electronic control unit 81. The coolant temperature sensor 84 outputs a signal corresponding to the coolant temperature in the vicinity of the coolant outlet of the cylinder head 12 (hereinafter, “coolant coolant temperature TW”) to the electronic control unit 81. The accelerator position sensor 85 outputs a signal corresponding to the depression amount of the accelerator pedal 2 (hereinafter referred to as “accelerator depression amount AP”) to the electronic control device 81.

  Control performed by the electronic control unit 81 will be described. Hereinafter, a period from when the start request for the internal combustion engine 1 is set to when the internal combustion engine 1 shifts to the idle operation state is referred to as “when the engine is started”. The period from when the request for stopping the internal combustion engine 1 is set to when the rotation of the internal combustion engine 1 stops is referred to as “when the engine is stopped”. Further, the period during which the rotation of the internal combustion engine 1 is stopped is referred to as “the engine is stopped”. Further, the engine operating state excluding the idling operation during the engine operation between the engine start and the engine stop is referred to as “normal engine operation”.

The electronic control unit 81 calculates the following parameters based on the output of each sensor.
(A) Based on the output signal of the crank position sensor 82, a calculation value corresponding to the crank angle CA is calculated.
(B) Based on the calculated value of the crank angle CA, a calculated value corresponding to the rotational speed of the crankshaft 15 (hereinafter referred to as “engine rotational speed NE”) is calculated.
(C) Based on the output signal of the cam position sensor 83, a calculation value corresponding to the cam angle DA is calculated.
(D) A calculation value corresponding to the valve timing VT is calculated based on the crank angle CA and the cam angle DA.
(E) Based on the output signal of the cooling water temperature sensor 84, a calculation value corresponding to the cooling water temperature TW is calculated.
(F) Based on the output signal of the accelerator position sensor 85, a calculated value corresponding to the accelerator depression amount AP is calculated.

  The electronic control unit 81 performs valve timing control for controlling the operation of the valve timing changing mechanism 30 and the valve timing fixing mechanism 40 based on the engine operating state, and operating speed learning control for learning the operating speed of the valve timing changing mechanism 30. . Note that the engine rotational speed NE and the engine load are used as parameters for defining the engine operating state.

  Valve timing control includes phase advance control for advancing valve timing VT during normal engine operation, phase retard control for retarding valve timing VT during normal engine operation, and valve timing VT during normal engine operation. Includes phase hold control for holding by hydraulic pressure. Further, phase lock control for fixing the valve timing VT by the valve timing lock mechanism 40 and phase release control for limiting a range in which the valve timing VT can be changed (hereinafter, “changeable range”) are included.

  The phase advance angle control and the phase delay angle control are requests that advance the valve timing VT (hereinafter, “phase advance angle request”) or requests that delay the valve timing VT (hereinafter, “phase delay control”). When the angle request “) is set, a target valve timing VT (hereinafter,“ target angle phase VTTrg ”) is set based on the engine operating state.

  Based on the calculated values of the target angle phase VTtrg and the valve timing VT, the oil control valve 72 for controlling the valve timing changing mechanism 30 to advance or retard is controlled.

Your phase retention system, a request to hold a predetermined phase of the valve timing VT hydraulically by a control to be performed separately (hereinafter, "phase holding request") when is set, perform the holding operation to the variable valve timing mechanism 30 The oil control valve 72 for controlling the oil is controlled.

Your the phase locked system, a request to fix the valve timing VT by control which is performed separately in the intermediate angular phase VTmdl (hereinafter, "phase locking request") when is set, perform the fixing operation to the valve timing locking mechanism 40 The oil switching valve 73 for controlling the oil is controlled. The phase lock request is set based on whether the engine stop condition is satisfied or the idle operation condition is satisfied. The fixing operation indicates the operation of the valve timing fixing mechanism 40 for fixing the valve timing VT to the intermediate angle phase VTmdl.

  In phase release control, phase restriction is performed to limit the changeable range. That is, when the phase limitation is being performed, the target angle phase VTtrg of the valve timing VT is set within the limited changeable range. Specifically, when there is a request to change the valve timing VT to the advance side with respect to the most advanced valve timing VT (hereinafter, “advance side limit phase VTcmax”) within the limited changeable range, The advance side limit phase VTcmax is set as the target angle phase VTtrg. Further, when there is a request to change the valve timing VT to the retard side from the most retarded phase within the limited changeable range (hereinafter, “retard side limit phase VTcmin”), the retard side limit phase VTcmin is set as the target angle phase VTtrg.

  In the operation speed learning control, the operation speed of the valve timing changing mechanism 30 is learned, and the changeable range is limited based on the learned operation speed. In limiting the changeable range, the retard side limit phase VTcmin and the advance side limit phase VTcmax are changed according to the operating speed.

  The operating speed of the valve timing changing mechanism 30 is such that when the valve timing VT changes from an arbitrary valve timing VT to another arbitrary valve timing VT, the change amount of the valve timing VT at that time is required for the change of the valve timing VT. It can be evaluated as a value divided by the time taken.

  When the valve timing changing mechanism 30 is fixed by the valve timing fixing mechanism 40, the valve timing VT is changed from this state to an arbitrary valve timing VT different from the intermediate angle phase VTmdl. The next time is used as the time required to change the valve timing VT. That is, the time until the operating state of the valve timing changing mechanism 30 changes from the phase fixed state to the phase released state, and the time until the valve timing VT changes from the intermediate angle phase VTmdl to the other arbitrary valve timing VT is determined. The included time is the time required for the change of the valve timing VT.

The structure of the valve timing changing mechanism 30 will be described with reference to FIG.
The valve timing changing mechanism 30 includes a housing rotor 31 that rotates in synchronization with the crankshaft 15 and a vane rotor 35 that rotates in synchronization with the intake camshaft 22.

  The valve timing VT is changed according to the rotational phase of the vane rotor 35 with respect to the housing rotor 31. Note that an arrow DR in the drawing indicates the rotation direction of the sprocket 33 (crankshaft 15) and the intake camshaft 22.

  The housing rotor 31 includes a housing main body 32 serving as a main body thereof, a sprocket 33 attached to one end of the housing main body 32 in the axial direction, and a cover 34 attached to the other end of the housing main body 32 in the axial direction. (See FIG. 3).

  The housing body 32 is provided with three partition walls 32 </ b> A that protrude in the radial direction of the rotation shaft of the housing rotor 31. The housing main body 32, the sprocket 33, and the cover 34 are fixed to each other by three bolts inserted in the axial direction.

  The vane rotor 35 is disposed in a space within the housing body 32. Further, it is fixed to the end of the intake camshaft 22. The vane rotor 35 is provided with three vanes 35 </ b> A that protrude toward the housing body 32.

  Three accommodating chambers 36 are formed in the valve timing changing mechanism 30. Each housing chamber 36 is formed by being surrounded by the outer peripheral wall portion of the housing body 32, the adjacent partition wall 32 </ b> A, the wall portion around the rotation axis of the vane rotor 35, the sprocket 33, and the cover 34. One vane 35 </ b> A is arranged in one storage chamber 36. Each storage chamber 36 is divided into an advance chamber 37 and a retard chamber 38 by a corresponding vane 35A.

  The advance chamber 37 is formed behind the vane 35 </ b> A in the accommodation chamber 36 on the rear side in the rotational direction DR of the intake camshaft. The retard chamber 38 is formed in the accommodation chamber 36 in front of the vane 35 </ b> A in the rotational direction DR of the intake camshaft 22. The volumes of the advance chamber 37 and the retard chamber 38 change according to the supply and discharge mode of the hydraulic oil to the valve timing changing mechanism 30.

  The valve timing fixing mechanism 40 is a first fixing mechanism 50 that restricts the rotation range of the vane rotor 35 relative to the housing rotor 31, and a second that restricts the rotation range of the vane rotor 35 relative to the housing rotor 31 to a range different from the first fixing mechanism 50. A fixing mechanism 60 is provided. The first fixing mechanism 50 and the second fixing mechanism 60 are arranged in different vanes 35A. When the rotation phase of the vane rotor 35 with respect to the housing rotor 31 is a rotation phase corresponding to the intermediate angle phase VTmdl (hereinafter referred to as “intermediate rotation phase”), the valve timing is determined by the cooperation of the first fixing mechanism 50 and the second fixing mechanism 60. VT is fixed to the intermediate angle phase VTmdl.

The operation of the valve timing changing mechanism 30 will be described.
When the vane rotor 35 rotates with respect to the housing rotor 31 in the advance side, that is, in the rotational direction DR by supplying hydraulic oil to the advance chamber 37 and discharging hydraulic oil from the retard chamber 38, the valve timing VT is advanced. To do. When the vane rotor 35 rotates to the most advanced angle side with respect to the housing rotor 31, that is, when the rotation phase of the vane rotor 35 with respect to the housing rotor 31 is the most forward rotation phase in the rotation direction DR, the valve timing VT is the most advanced angle phase. Set to VTmax.

  When the vane rotor 35 rotates with respect to the housing rotor 31 on the retard side, that is, on the opposite side to the rotational direction DR by discharging the hydraulic oil from the advance chamber 37 and supplying the hydraulic oil to the retard chamber 38, the valve timing VT is retarded. When the vane rotor 35 rotates most retarded with respect to the housing rotor 31, that is, when the rotational phase of the vane rotor 35 with respect to the housing rotor 31 is the rearmost rotational phase in the rotational direction DR, the valve timing VT is the most retarded phase. Set to VTmin.

  With reference to FIG. 3 and FIG. 4, the structure of the 1st fixing mechanism 50 and the 2nd fixing mechanism 60 is demonstrated. 3 and 4 show a cross-sectional structure of the valve timing changing mechanism 30 along the line AA in FIG. 2 developed on a plane. 3 and 4 show a state in which the rotation phase of the vane rotor 35 with respect to the housing rotor 31 is in the intermediate rotation phase. In the following, the direction in which the first fixing pin 51 of the first fixing mechanism 50 and the second fixing pin 61 of the second fixing mechanism 60 protrude from the vane 35A is referred to as a “projection direction ZA”, and the first fixing pin 51 and the second fixing pin 61 The direction in which the fixing pin 61 is accommodated in the vane 35A is referred to as “accommodating direction ZB”.

The configuration of the first fixing mechanism 50 is shown below.
The first fixing mechanism 50 includes a first fixing pin 51 that moves in the axial direction of the vane rotor 35 with respect to the vane 35A, and a first fixing spring 52 that pushes the first fixing pin 51 in the protruding direction ZA. . In addition to this, a first fixing chamber 53 that accommodates the first fixing pin 51 and the first fixing spring 52, a first engagement groove 56 that is formed corresponding to a circumferential locus of the first fixing pin 51, and It has.

  The first fixed chamber 53 is formed in the vane 35A. The first fixing pin 51 is partitioned into a first release chamber 54 and a first spring chamber 55. Note that when there is no flow of hydraulic oil through the clearances of the parts constituting the first fixing mechanism 50, no flow of hydraulic oil is formed between the first release chamber 54 and the first spring chamber 55. .

  The first engagement groove 56 includes two grooves having different depths, that is, a first lower groove 57 having a relatively large depth and a first upper groove 58 having a relatively small depth. The first upper groove 58 is provided on the retard side with respect to the first lower groove 57.

  A first advance end 56A, which is an end on the advance side of the first lower groove 57, is formed at a position corresponding to the end face on the advance side of the first fixing pin 51 of the vane rotor 35 in the intermediate rotation phase. Has been. The first retarded end 56B, which is the retarded end of the first upper groove 58, is formed on the retarded side with respect to the first advanced end 56A. The second retarded end portion 56C, which is the retarded end portion of the first lower groove 57, is formed between the first advanced angle end portion 56A and the first retarded angle end portion 56B.

The configuration of the second fixing mechanism 60 is shown below.
The second fixing mechanism 60 includes a second fixing pin 61 that moves in the axial direction of the vane rotor 35 with respect to the vane 35A, and a second fixing spring 62 that pushes the second fixing pin 61 in the protruding direction ZA. . In addition to this, a second fixing chamber 63 that accommodates the second fixing pin 61 and the second fixing spring 62, a second engagement groove 66 that is formed corresponding to the trajectory in the circumferential direction of the second fixing pin 61, and It has.

  The second fixed chamber 63 is formed in the vane 35A. The second fixing pin 61 divides the second release chamber 64 and the second spring chamber 65. Note that when there is no flow of hydraulic oil through the clearances of the components constituting the second fixing mechanism 60, no hydraulic oil flow is formed between the second release chamber 64 and the second spring chamber 65. .

  The second engagement groove 66 includes two grooves having different depths, that is, a second lower groove 67 having a relatively large depth and a second upper groove 68 having a relatively small depth. The second upper groove 68 is provided on the retard side with respect to the second lower groove 67.

  The fourth retarded angle end 66C, which is the retarded end of the second lower groove 67, is formed at a position corresponding to the retarded end face of the second fixed pin 61 of the vane rotor 35 in the intermediate rotational phase. Has been. The third retarded end portion 66B, which is the retarded end portion of the second upper groove 68, is formed on the retarded side with respect to the fourth retarded end portion 66C. The second advance angle end portion 66A that is the end portion on the advance angle side of the second lower groove 67 is formed on the advance angle side with respect to the fourth retard angle end portion 66C.

The operation of the valve timing fixing mechanism 40 will be described with reference to FIGS.
The first fixing pin 51 and the second fixing pin 61 have a force acting on the first fixing pin 51 or the second fixing pin 61 based on the hydraulic pressure of the first release chamber 54 or the second release chamber 64 and the first fixing spring 52. Or according to the relationship with the spring force of the 2nd fixed spring 62, it operate | moves in the range from the accommodation position shown in FIG. 3 to the protrusion position shown in FIG. 4 in the axial direction.

  The protruding position of the first fixing pin 51 indicates the position when the tip of the first fixing pin 51 is in contact with the bottom surface of the first lower groove 57 of the first engagement groove 56. The protruding position of the second fixing pin 61 indicates a position when the tip of the second fixing pin 61 is in contact with the bottom surface of the second lower groove 67 of the second engagement groove 66. Moreover, the accommodation position of the 1st fixing pin 51 shows a position when the front-end | tip of the 1st fixing pin 51 is accommodated in vane 35A. Moreover, the accommodation position of the 2nd fixing pin 61 shows a position when the front-end | tip of the 2nd fixing pin 61 is accommodated in vane 35A.

  Specific operation modes of the first fixing pin 51 with respect to the vane 35A are shown in the following (A) and (B). Since the second fixing pin 61 also operates in a manner according to the first fixing pin 51, the description of the operation of the second fixing pin 61 is omitted here.

  (A) When the force acting on the first fixing pin 51 based on the hydraulic pressure of the first release chamber 54 is smaller than the spring force of the first fixing spring 52, a force (the force that moves the first fixing pin 51 in the protruding direction ZA) Hereinafter, “sudden output”) is continuously applied to the first fixing pin 51. The first fixing pin 51 is in a position corresponding to the first lower groove 57 of the first engaging groove 56, the position of the first fixing pin 51 with respect to the vane 35A is in the receiving position, and the first fixing pin 51 When the projecting output acts on the first fixed pin 51, the position of the first fixing pin 51 changes from the accommodation position to the projecting position.

  (B) When the force acting on the first fixing pin 51 based on the hydraulic pressure of the first release chamber 54 is larger than the spring force of the first fixing spring 52, the force that moves the first fixing pin 51 in the accommodation direction ZB ( Hereinafter, “accommodating power”) is continuously applied to the first fixing pin 51. Then, when the position of the first fixing pin 51 with respect to the vane 35A is in the protruding position and the protruding output is acting on the first fixing pin 51, the position of the first fixing pin 51 changes from the protruding position to the accommodation position. .

The valve timing fixing mechanism 40 fixes the valve timing VT as follows.
When the position of the first fixing pin 51 is the protruding position, the vane rotor 35 is restricted from rotating relative to the housing rotor 31 in the advance direction relative to the intermediate rotation phase. When the position of the second fixing pin 61 is the protruding position, the vane rotor 35 is restricted from rotating relative to the housing rotor 31 in the retarding direction with respect to the intermediate rotation phase.

  For this reason, when the 1st fixed pin 51 and the 2nd fixed pin 61 exist in a protrusion position, the vane rotor 35 cannot rotate to an advance angle direction and a retard angle direction from an intermediate rotation phase with respect to the housing rotor 31. FIG. That is, the valve timing VT is fixed to the intermediate angle phase VTmdl when the first fixing pin 51 and the second fixing pin 61 and the housing rotor 31 are in contact with each other.

  Here, with respect to the operation state of the valve timing changing mechanism 30 and the operation state of the valve timing fixing mechanism 40, a “phase release state” and a “phase fixed state” are defined as follows.

  The operation state of the valve timing fixing mechanism 40 when the positions of the first fixing pin 51 and the second fixing pin 61 are in the storage position is referred to as “the phase release state of the valve timing fixing mechanism 40”. Further, since the operation state of the valve timing fixing mechanism 40 is set to the phase release state, the operation state of the valve timing change mechanism 30 capable of changing the valve timing VT is referred to as “the phase release state of the valve timing change mechanism 30”. And FIG. 3 shows an example when the operation states of the valve timing changing mechanism 30 and the valve timing fixing mechanism 40 are in the phase release state.

  The operation state of the valve timing fixing mechanism 40 when the positions of the first fixing pin 51 and the second fixing pin 61 are in the protruding position is referred to as “phase fixing state of the valve timing fixing mechanism 40”. Further, since the operation state of the valve timing fixing mechanism 40 is set to the phase fixed state, the operation state of the valve timing changing mechanism 30 in which the valve timing VT is fixed to the intermediate angle phase VTmdl is changed to “valve timing changing mechanism 30”. Phase locked state ”. FIG. 4 shows the phase locked state of the valve timing changing mechanism 30 and the valve timing fixing mechanism 40.

The control of the oil control valve 72 will be described.
The electronic control device 81 changes the operation state of the oil control valve 72 (hereinafter referred to as “OCV operation mode”) by changing the DUTY ratio as a command signal for the actuator of the oil control valve 72.

  Specifically, an area that can be taken by the DUTY ratio is divided into three areas according to the magnitude of the DUTY ratio, and each of the divided areas is associated with the OCV operation mode in advance. When the OCV operation mode to be applied to the oil control valve 72 is selected, the DUTY ratio corresponding to the selected OCV operation mode is output to the actuator of the oil control valve 72. Further, by changing the DUTY ratio in the DUTY ratio region corresponding to each OCV operation mode, the supply speed and the discharge speed as the hydraulic oil supply / discharge mode are changed.

The relationship between each OCV operation mode and the operation of the valve timing changing mechanism 30 is shown below.
(A) When the OCV operation mode is set to the advance angle mode, the hydraulic oil is supplied to the advance chamber 37 and the hydraulic oil is discharged from the retard chamber 38. For this reason, the vane rotor 35 rotates in the advance direction with respect to the housing rotor 31. Further, by changing the DUTY ratio within the range of the DUTY ratio associated with the advance angle mode, the speed at which the vane rotor 35 rotates in the advance direction with respect to the housing rotor 31 (hereinafter, “advance angle speed”) is changed. can do.

  (B) When the OCV operation mode is set to the holding mode, the advance chamber 37 and the retard chamber 38 are closed. For this reason, the rotational position of the vane rotor 35 with respect to the housing rotor 31 is maintained.

  (C) When the OCV operation mode is set to the retard angle mode, the hydraulic oil is discharged from the advance chamber 37 and the hydraulic oil is supplied to the retard chamber 38. For this reason, the vane rotor 35 rotates in the retard direction with respect to the housing rotor 31. Further, by changing the DUTY ratio within the range of the DUTY ratio associated with the retard angle mode, the speed at which the vane rotor 35 rotates in the retard direction with respect to the housing rotor 31 (hereinafter, “retard angle speed”) is changed. can do.

The control of the oil switching valve 73 will be described.
The electronic control device 81 changes the operation state of the oil switching valve 73 (hereinafter referred to as “OSV operation mode”) by changing a command signal for the actuator of the oil switching valve 73.

The relationship between each OSV operation mode and the operation of the valve timing fixing mechanism 40 is shown below.
(A) When the OSV operation mode is set to the fixed mode, the hydraulic oil is discharged from the first release chamber 54 and the second release chamber 64. For this reason, a projecting output acts on the first fixing pin 51 and the second fixing pin 61.

  (B) When the OSV operation mode is set to the release mode, hydraulic oil is supplied to the first release chamber 54 and the second release chamber 64. For this reason, accommodating force acts on the first fixing pin 51 and the second fixing pin 61.

  In the valve timing control, the electronic control device 81 controls the oil control valve 72 and the oil switching valve 73 according to the engine operating state as in the following (A) to (D).

  (A) During normal engine operation, an advance angle mode, a hold mode, or a retard angle mode is selected as the OCV operation mode according to the engine operation state. Also, the OSV operation mode is set to the release mode.

  (B) When the phase fixing request is set during normal engine operation, the OSV operation mode is changed from the release mode to the fixed mode. Further, an OCV operation mode for changing the valve timing VT to the intermediate angle phase VTmdl is selected. Examples of when the phase fixing request is set during normal engine operation include when the engine stop condition is satisfied during normal engine operation and when the idle operation condition is satisfied during normal engine operation.

  (C) At the time of engine start, when the operation state of the valve timing changing mechanism 30 is in the phase fixed state and the release condition at start is not satisfied, the phase advance request, the phase retard request, or the phase hold request The change of the operating state of the valve timing changing mechanism 30 is prohibited. This control is performed with priority over the following control (D).

  (D) At the time of engine start or idle operation, the operation state of the valve timing changing mechanism 30 is in a phase-fixed state, the start-time release condition is satisfied, and a phase advance request or phase retard request is set The OSV operation mode is changed from the fixed mode to the release mode. Further, the OCV operation mode is changed from the hold mode to the advance angle mode or the retard angle mode.

  The release condition at the start is set as a condition for confirming that there is little possibility that the valve timing VT becomes unstable even when the operation state of the valve timing changing mechanism 30 is changed to the phase release state when the engine is started. Has been. Further, the state in which the valve timing VT is unstable indicates a state in which the variation in the valve timing VT is large because the advance chamber 37 and the retard chamber 38 are not filled with hydraulic oil.

  In the control of (D) above, the changeable range set by the operation speed learning control when the operation state of the valve timing changing mechanism 30 is set to the phase release state based on the fact that the release at the start is established when the engine is started. Is used to execute the phase release control.

The purpose of the phase cancellation control will be described.
After the engine is started, after the operating state of the valve timing changing mechanism 30 is changed from the phase fixed state to the phase released state and when an engine stall occurs, a phase fixed request is set. Thus, control is performed to change the valve timing VT to the intermediate angle phase VTmdl while the engine speed NE is decreasing.

  At this time, since the combustion of the internal combustion engine 1 is stopped, the hydraulic pressure of the valve timing changing mechanism 30 gradually decreases. When the hydraulic pressure of the valve timing changing mechanism 30 falls below a predetermined hydraulic pressure, the valve timing VT cannot be controlled by the hydraulic pressure. For this reason, in order to set the operation state of the valve timing changing mechanism 30 to the phase-fixed state when the engine stall occurs, an elapsed period after the engine stall occurs (hereinafter, “post-stall period”) is a controllable period. It is preferable to change the valve timing VT to the intermediate angle phase VTmdl until the value exceeds. The controllable period indicates a period until the hydraulic pressure of the valve timing changing mechanism 30 falls below a predetermined hydraulic pressure after the engine stall has occurred. The length of this controllable period varies every time an engine stall occurs.

  On the other hand, as the difference between the valve timing VT at the time of engine stall and the intermediate angle phase VTmdl is larger, the amount of change in the valve timing VT required to reach the valve timing VT to the intermediate angle phase VTmdl in the controllable period. Becomes larger. For this reason, there is a high possibility that the valve timing VT does not reach the intermediate angle phase VTmdl within the controllable period.

  Therefore, in the phase release control, when the operation state of the valve timing changing mechanism 30 is changed from the phase fixed state to the phase released state after the engine start is completed, the phase restriction is executed according to the cooling water temperature TW.

  When the phase limit is being executed and the valve timing VT is on the advance side with respect to the intermediate angle phase VTmdl, the maximum difference between the intermediate angle phase VTmdl and the valve timing VT is the advance angle limit phase VTcmax and the intermediate angle This is the difference from the phase VTmdl. The difference in the valve timing VT is smaller than the difference between the most advanced angle phase VTmax and the intermediate angle phase VTmdl.

  Further, when the valve timing VT is on the retard side with respect to the intermediate angle phase VTmdl, the maximum difference between the intermediate angle phase VTmdl and the valve timing VT is the difference between the retard side limit phase VTcmin and the intermediate angle phase VTmdl. . The difference in the valve timing VT is smaller than the difference between the most retarded angle phase VTmin and the intermediate angle phase VTmdl.

  For this reason, it is necessary to make the valve timing VT reach the intermediate angle phase VTmdl when an engine stall occurs during execution of phase limiting, as compared to when engine stall occurs during non-execution of phase limiting. The maximum change amount of the valve timing VT is reduced. That is, by executing the phase limitation, the valve timing VT is likely to reach the intermediate angle phase VTmdl within the controllable period.

With reference to FIG. 5, a specific procedure for phase release control will be described.
This control is repeatedly performed by the electronic control device 81 every predetermined control cycle. That is, after the process of the last step is completed, the execution of the control is suspended until a predetermined control period elapses, and when the predetermined control period elapses, the phase release control is performed again from the first step. .

  In step S11, it is determined whether or not the operation state of the valve timing changing mechanism 30 is the phase release state. When it is determined in step S11 that the operation state of the valve timing changing mechanism 30 is in the phase release state, the process proceeds to step S12. On the other hand, when it is determined in step S11 that the operation state of the valve timing changing mechanism 30 is not in the phase release state, that is, when it is determined that the operation state of the valve timing changing mechanism 30 is in the phase fixed state, this processing is temporarily terminated. To do.

  In step S12, it is determined whether or not the cooling water temperature TW is equal to or lower than a predetermined cooling water temperature TW (hereinafter, “predetermined water temperature TWX”). The predetermined water temperature TWX is set to a temperature at which the operation speed of the valve timing changing mechanism 30 is equal to or higher than a predetermined speed regardless of the components of the hydraulic oil. The predetermined speed corresponds to the lowest operating speed among the operating speeds of the valve timing changing mechanism 30 required during normal engine operation.

  In step S12, when it is determined that the cooling water temperature TW is equal to or lower than the predetermined water temperature TWX, phase restriction for restricting the changeable range is executed in step S13. On the other hand, when it is determined in step S12 that the cooling water temperature TW is higher than the predetermined water temperature TWX, the phase restriction is canceled in step S14.

With reference to FIG. 6, an example of an execution mode of the phase cancellation control will be described.
At time t10, that is, when the starting release condition is satisfied, the operation state of the valve timing changing mechanism 30 is changed from the phase fixed state to the phase released state. Further, phase limitation is executed based on the fact that the cooling water temperature TW is equal to or lower than the predetermined water temperature TWX.

  At time t11, that is, when the cooling water temperature TW exceeds the predetermined water temperature TWX, the phase restriction is released. Thereafter, the valve timing VT is changed between the most advanced angle phase VTmax and the most retarded angle phase VTmin based on the engine operating state.

  By the way, in different types of hydraulic oil, the components of the hydraulic oil are different from each other. Moreover, the component of hydraulic fluid changes when hydraulic fluid deteriorates. In the hydraulic oil having different components, the viscosity of the hydraulic oil (hereinafter, “oil viscosity”) is different even at the same oil temperature.

  Here, on the assumption that the oil temperature and the engine rotational speed NE are equal to each other, a valve when hydraulic oil having a relatively high oil viscosity is used (hereinafter, “when using high-viscosity oil”) is used. When the operating speed of the timing changing mechanism 30 is compared with the operating speed of the valve timing changing mechanism 30 when hydraulic oil having a relatively low oil viscosity is used (hereinafter, “when using low viscosity oil”), Since the resistance of the high-viscosity hydraulic oil is large, the former operating speed is smaller than the latter operating speed. That is, the operating speed of the valve timing changing mechanism 30 does not change only under the influence of the oil temperature, but also changes under the influence of the oil viscosity due to the difference in the components of the hydraulic oil.

  Thus, when the high-viscosity oil is used, the operating speed of the valve timing changing mechanism 30 is lower than when the low-viscosity oil is used. There is a high possibility that the timing VT does not reach the intermediate angle phase VTmdl.

  On the other hand, when the low-viscosity oil is used, the operating speed of the valve timing changing mechanism 30 is higher than when the high-viscosity oil is used. Therefore, when an engine stall occurs when using the low-viscosity oil, the valve timing VT is within the controllable period. Is unlikely to reach the intermediate angle phase VTmdl. For this reason, it is allowed to expand the size of the changeable range when using the low-viscosity oil to be larger than the size of the changeable range when using the high-viscosity oil. Therefore, in the operation speed learning control, the size of the changeable range used for phase limitation is changed according to the operation speed of the valve timing change mechanism 30.

A specific procedure of the operation speed learning control will be described with reference to FIG.
This control is repeatedly performed by the electronic control device 81 every predetermined control cycle. That is, after the process of the last step is completed, the execution of the control is suspended until a predetermined control period elapses, and the operation speed learning control is performed again from the first step when the predetermined control period elapses. .

In step S21, it is determined whether or not a learning condition is satisfied. Here, it is determined that the learning condition is satisfied based on the fact that all the following conditions (A) to (E) are satisfied. And when it determines with learning conditions having been satisfied in step S21, it transfers to the process of step S22. On the other hand, when it is determined in step S21 that the learning condition is not satisfied, this process is temporarily ended.
(A) The valve timing fixing mechanism 40 is in a phase fixed state.
(B) The cooling water temperature TW is equal to or higher than the temperature indicating completion of warm-up.
(C) The vehicle is idling.
(D) The start release condition is satisfied and the phase advance angle request is set.
(E) The operation speed learning control is not performed after the current engine start.

In step S22, the advance angle mode is selected as the OCV operation mode, the maximum advance angle speed is selected as the advance angle speed, and the OSV operation mode is set to the release mode.
In step S23, it is determined whether or not the valve timing VT has reached a predetermined valve timing VT (hereinafter, “determination angle phase VTjdg”). When it is determined that the valve timing VT has reached the determination angular phase VTjdg, the process proceeds to step S24. Note that the determination process of step S23 is repeatedly executed until the valve timing VT reaches the determination angle phase VTjdg.

  In step S24, the valve timing changing mechanism is based on the elapsed time from when the process of step S22 is executed until the valve timing VT reaches the determination angle phase VTjdg, and the engine speed NE when the process of step S22 is executed. 30 learning operation speeds VM are calculated. The learning operation speed VM decreases as the engine speed NE increases when the elapsed time until the valve timing VT reaches the determination angular phase VTjdg is the same. It should be noted that, during the elapsed period, the period until the operation state of the valve timing changing mechanism 30 is changed from the phase fixed state to the phase released state, and the valve timing VT changes from the intermediate angle phase VTmdl to the determination angle phase VTjdg. This period is included.

  In step S25, the changeable range corresponding to the learning operation speed VM is set as a changeable range used for phase restriction by applying the learning operation speed VM calculated in step S24 to the changeable range map (see FIG. 8). .

The configuration of the changeable range map will be described with reference to FIG.
In the changeable range map, the size of the changeable range on the retard side of the changeable range from the intermediate angle phase VTmdl (hereinafter referred to as “retarding side limit range”) and the changeable range from the intermediate angle phase VTmdl. Also, the size of the advanceable side changeable range (hereinafter referred to as “advanced side limit range”) is defined in accordance with the learning operation speed VM. Further, the retard side limit range and the advance side limit range are respectively defined so as to increase stepwise as the learning operation speed VM increases.

  With reference to FIG. 9, an example of an execution mode of the operation speed learning control when using low viscosity oil and when using high viscosity oil will be described. In addition, the continuous line in a figure shows the execution aspect at the time of low-viscosity oil use, and the broken line in the figure has shown the execution aspect at the time of high-viscosity oil use. In each execution mode, the oil temperature and the engine speed NE are assumed to be equal.

The flow of operation speed learning control when using low viscosity oil is shown below.
At time t20, that is, when the accelerator pedal 2 is depressed, a phase advance request is set based on this. For this reason, the OSV operation mode is changed from the fixed mode to the release mode. Further, the OCV operation mode is changed from the holding mode to the advance angle mode. In the advance angle mode, the maximum advance speed is set.

  At time t21, that is, when the fixing pins 51 and 61 move to the accommodation position, the operation state of the valve timing changing mechanism 30 changes from the phase fixing state to the phase releasing state. As a result, the valve timing VT starts to advance from the intermediate angle phase VTmdl toward the target angle phase VTtrg.

  At time t23, that is, when the valve timing VT reaches the determination angular phase VTjdg, the learning operation speed VM is calculated based on the elapsed period from the time t20 to the time t23 and the engine speed NE.

  At time t25, that is, when the valve timing VT reaches the target angle phase VTtrg, the OCV operation mode is changed from the advance angle mode to the hold mode. Thereafter, the valve timing VT is changed between the most advanced angle phase VTmax and the most retarded angle phase VTmin based on the engine operating state.

The flow of operation speed learning control when using high viscosity oil is shown below.
At time t22, that is, when the fixing pins 51 and 61 move to the accommodation position, the operation state of the valve timing changing mechanism 30 changes from the phase fixing state to the phase releasing state. As a result, the valve timing VT starts to advance from the intermediate angle phase VTmdl toward the target angle phase VTtrg.

  At time t24, that is, when the valve timing VT reaches the determination angular phase VTjdg, the learning operation speed VM is calculated based on the elapsed period from the time t20 to the time t24 and the engine speed NE.

  At time t26, that is, when the valve timing VT reaches the target angle phase VTtrg, the OCV operation mode is changed from the advance angle mode to the hold mode. Thereafter, the valve timing VT is changed between the most advanced angle phase VTmax and the most retarded angle phase VTmin based on the engine operating state.

  As described above, the period from when the phase advance angle request is set to when the valve timing changing mechanism 30 is changed from the phase locked state to the phase released state is the time when high viscosity oil is used (elapsed from time t20 to time t22). The period when the low-viscosity oil is used (the elapsed period from time t20 to time t21) is smaller than the period.

  The period from when the operating state of the valve timing changing mechanism 30 changes from the phase fixed state to the phase released state until the valve timing VT reaches the determination angle phase VTjdg is when using high-viscosity oil (from time t22 to time When using low-viscosity oil (elapsed period from time t21 to time t23) is smaller than (elapsed period until t24).

  The period when the above periods are combined, that is, the period from when the phase advance angle request is set to when the valve timing VT reaches the determination angle phase VTjdg, is when the high viscosity oil is used (from time t20 to time t24). When the low viscosity oil is used (elapsed period from time t20 to time t23) is smaller than (elapsed period).

(Effect of embodiment)
According to the internal combustion engine 1 of the present embodiment, the following effects can be obtained.
(1) The electronic control unit 81 limits the changeable range according to the learning operation speed VM of the valve timing changing mechanism 30. According to this configuration, since the changeable range is limited based on the learning operation speed VM in which the difference in oil viscosity is reflected, the operation of the valve timing changing mechanism 30 is uniformly limited when the oil temperature is low. In comparison, more situations in which the valve timing VT can be changed according to the engine operating state can be ensured.

  (2) The electronic control unit 81 makes the size of the retard side limit range when using high viscosity oil smaller than the size of the retard side limit range when using low viscosity oil. According to this configuration, the maximum difference between the valve timing VT and the intermediate angle phase VTmdl is low when the valve timing VT is on the retard side with respect to the intermediate angle phase VTmdl when the high-viscosity oil is used and the phase restriction is being executed. Smaller than when using viscous oil. For this reason, when the valve timing VT is on the retard side with respect to the intermediate angle phase VTmdl, the frequency of stopping the engine can be reduced without changing the operation state of the valve timing changing mechanism 30 to the phase fixed state.

  (3) The electronic control unit 81 makes the advance side limit range when using high viscosity oil smaller than the advance side limit range when using low viscosity oil. According to this configuration, the maximum difference between the valve timing VT and the intermediate angle phase VTmdl is low when the valve timing VT is on the more advanced side than the intermediate angle phase VTmdl when the high-viscosity oil is used and phase restriction is being performed. Smaller than when using viscous oil. Therefore, when the valve timing VT is on the more advanced side than the intermediate angle phase VTmdl, it is possible to reduce the frequency at which the engine stops without changing the operation state of the valve timing changing mechanism 30 to the phase fixed state.

  (4) The torque of the intake camshaft 22 varies in the advance direction and the retard direction. Further, the torque acting in the retard direction is larger than the torque acting in the advance direction. For this reason, when the valve timing VT is advanced, the resistance applied to the valve timing changing mechanism 30 is larger than when the valve timing VT is retarded. Thereby, the difference in operating speed of the valve timing changing mechanism 30 due to the difference in oil viscosity is easier to detect when the valve timing VT is advanced than when the valve timing VT is retarded. Since the electronic control unit 81 of the above embodiment learns the learning operation speed VM when the valve timing VT is advanced, the frequency at which the operation speed of the valve timing changing mechanism 30 is appropriately learned increases.

  (5) The electronic control unit 81 learns the learning operation speed VM when the valve timing VT starts to advance. According to this configuration, since the learning operation speed VM is learned in accordance with the change speed of the valve timing VT from this state on the basis of the change speed of the valve timing VT being “0”, the change speed of the valve timing VT. Compared to a configuration in which learning is performed based on a state in which the learning speed fluctuates, the learning operation speed VM is appropriately learned more frequently.

  (6) The electronic control unit 81 learns the learning operation speed VM according to the operation speed of the valve timing changing mechanism 30 when the start-time release condition is satisfied and the phase advance angle request is set. . According to this configuration, compared with the configuration in which the valve timing changing mechanism 30 is operated for learning the learning operation speed VM, the valve timing VT is not suitable for the engine operating state as the learning operation speed VM is learned. The frequency of change can be reduced.

  Further, the learning operation speed VM is learned on the basis of the phase advance angle request caused by the depression of the accelerator pedal 2, so that the learning is compared with the configuration in which the valve timing VT is changed for learning the learning operation speed VM. There is little risk that the driver will feel uncomfortable.

  (7) When learning the learning operation speed VM, the electronic control device 81 sets the advance speed of the valve timing VT by the oil control valve 72 to the maximum advance speed. According to this configuration, it is possible to suppress an increase in the time until the valve timing VT reaches the target angular phase VTtrg.

  (8) In the internal combustion engine 1 that supplies hydraulic oil to the valve timing changing mechanism 30 by the torque of the crankshaft 15, the operating speed of the valve timing changing mechanism 30 changes according to the engine rotational speed NE. Since the electronic control unit 81 of the above embodiment learns the learning operation speed VM in consideration of the engine rotation speed NE, it is possible to reduce the influence of the engine rotation speed NE on the learning operation speed VM. For this reason, it is possible to learn the operation speed of the valve timing changing mechanism 30 in which the influence of the oil viscosity is more appropriately reflected.

(Other embodiments)
The embodiment of the present invention is not limited to the above embodiment, and can be modified as shown below, for example. The following modifications are not applied only to the above-described embodiment, and different modifications can be combined with each other.

  In the above embodiment (FIG. 8), the retard side limit range and the advance side limit range are gradually increased as the learning operation speed VM increases. Regardless, the advance side limit phase VTcmax can be set to a constant magnitude.

  In the above embodiment (FIG. 8), the advance side limit range is increased as the learning operation speed VM is increased. However, the advance side limit range is increased as the learning operation speed VM is increased. It can also be made smaller. As a specific method for reducing the advance side limit range as described above, for example, the increase amount of the learning operation speed VM is larger than the increase amount of the retard side limit range with respect to the increase amount of the learning operation speed VM. The amount of decrease in the size of the advance side limit range with respect to is increased. In this modification, the retard side limit range becomes smaller as the learning operation speed VM becomes smaller, so that the effect (2) of the embodiment can be obtained.

  In the above embodiment (FIG. 8), the retard side limit range is increased stepwise as the learning operation speed VM increases. However, the retard side limit range is increased as the learning operation speed VM increases. Can be continuously increased. For example, the retard angle limit phase VTcmin can be increased linearly as the learning operation speed VM increases.

  In the above embodiment (FIG. 8), the advance side limit range is increased stepwise as the learning operation speed VM increases. However, the advance side limit range increases as the learning operation speed VM increases. Can be continuously increased. For example, the advance side limit phase VTcmax can be increased linearly as the learning operation speed VM increases.

  In the above embodiment (FIG. 8), as the learning operation speed VM increases, the size of the retard side limit range and the size of the advance side limit range are increased in stages, but the learning operation speed VM is It is also possible to set the intermediate angle phase VTmdl as a changeable range when it is smaller than the predetermined operation speed. In this case, the operation state of the valve timing changing mechanism 30 can be set to a fixed operation state.

  In the above embodiment (FIG. 7), one of the learning conditions is that the cooling water temperature TW is equal to or higher than the temperature indicating completion of warming up. However, instead of this condition, the cooling water temperature TW is warm. It can be used as a learning condition that the temperature is lower than the temperature indicating completion of the machine.

  In the above embodiment (FIG. 7), the fact that the valve timing changing mechanism 30 is in the phase-fixed state and the idle operation state is used as one of the learning conditions, but instead of these conditions, It can also be used as a learning condition that the valve timing changing mechanism 30 is in a phase-released state and during normal engine operation.

  In the above embodiment (FIG. 7), the idle operation state and the setting of the phase advance angle request are used as one of the learning conditions, but instead of these conditions, normal engine operation is performed. It can also be used as a learning condition that it is time and a phase retardation request is set. In this case, the learning operation speed VM is calculated on the basis of the period until the predetermined valve timing VT that is retarded from the valve timing VT at that time is reached.

  In the above embodiment (FIG. 7), the learning operation speed VM is calculated according to the engine speed NE, but the learning operation speed VM is corrected based on the coolant temperature TW when the operation speed learning control is performed. You can also In this case, the learning operation speed VM increases as the cooling water temperature TW decreases.

  In the above embodiment (FIG. 7), when learning learning speed VM is learned, the maximum advance speed is set in the advance mode, but an advance speed smaller than the maximum advance speed can also be set.

  In the above embodiment (FIG. 5), the phase limitation is canceled based on the cooling water temperature TW, but a “limit period” is set as a period for limiting the size of the changeable range, and the set limit period The phase restriction can also be canceled based on Note that the limit period is set to be shorter as the learning operation speed VM increases. In this case, the size of the limited changeable range can be set to a constant size regardless of the learning operation speed VM.

With reference to FIG. 10, the content of the phase cancellation control using the limited period will be described.
This control is repeatedly performed by the electronic control device 81 every predetermined control cycle. That is, after the process of the last step is completed, the execution of the control is suspended until a predetermined control period elapses, and when the predetermined control period elapses, the phase release control is performed again from the first step. .

  When it is determined in step S31 that the phase is released, and in step S32, it is determined that the cooling water temperature TW is equal to or lower than the predetermined water temperature TWX, phase restriction is executed in step S33.

  In step S34, it is determined whether or not the elapsed period from the start of the execution of the phase limit has exceeded the limit period set according to the learning operation speed VM. When it is determined that the elapsed period from the start of the execution of the phase limitation does not exceed the limitation period, the determination in step S34 is performed again after a predetermined period. On the other hand, when it is determined that the elapsed period from the start of the phase limit has exceeded the limit period, the phase limit is canceled in step S35.

  In the above embodiment (FIG. 5), the phase limit is executed when the cooling water temperature TW is equal to or lower than the predetermined water temperature TWX, but the magnitude of the predetermined water temperature TWX is changed according to the learning operation speed VM. You can also. In this case, the size of the limited changeable range can be set to a constant size regardless of the learning operation speed VM.

  In the above embodiment (FIG. 7), the size of the changeable range is set according to the learning operation speed VM, but the method for setting the size of the changeable range can also be set as follows. That is, when the hydraulic oil is replaced, an input unit is provided for inputting at least one of the components of the hydraulic oil, the type of hydraulic oil, and the oil viscosity to the electronic control device 81. Then, the size of the changeable range is set based on the input information. In this case, it is also possible to add a process of estimating the deterioration state of the hydraulic oil based on the elapsed time since the replacement of the hydraulic oil and setting the size of the changeable range in consideration of the estimated deterioration state.

  In the above embodiment (FIG. 1), the oil control valve 72 controls the supply and discharge mode of the hydraulic oil for the advance chamber 37 and the retard chamber 38, and the oil switching valve 73 operates for the release chambers 54 and 64. Although the oil supply / discharge mode is controlled, a single oil control valve for controlling the hydraulic oil supply / discharge mode of the advance chamber 37, the retard chamber 38, and the release chambers 54 and 64 may be provided. .

In the above embodiment (FIG. 3), the first engagement groove 56 including the first lower groove 57 and the first upper groove 58 is formed in the first fixing mechanism 50. It is also possible to add at least one of the following (A) and (B).
(A) Instead of the first lower groove 57, a hole for fitting the first fixing pin 51 is formed at a position corresponding to the first fixing pin 51 of the intermediate rotation phase. In this case, the end of the first upper groove 58 is extended to the hole at the same position.
(B) The first upper groove 58 is omitted.

In the embodiment (FIG. 3), the second engagement groove 66 including the second lower groove 67 and the second upper groove 68 is formed in the second fixing mechanism 60. It is also possible to add at least one of the following (A) and (B).
(A) Instead of the second lower groove 67, a hole for fitting the second fixing pin 61 is formed at a position corresponding to the second fixing pin 61 of the intermediate rotation phase.
(B) The second upper groove 68 is omitted.

  In the above embodiment (FIG. 3), the first fixing pin 51 and the second fixing pin 61 are provided in the vane rotor 35, and the first engagement groove 56 and the second engagement groove 66 are formed in the housing rotor 31. However, the structure regarding each fixing pin 51 and 61 and each engaging groove 56 and 66 can also be changed as follows. That is, at least one of the first engagement groove 56 and the second engagement groove 66 can be formed in the vane rotor 35, and at least one of the first fixing pin 51 and the second fixing pin 61 can be provided in the housing rotor 31.

  In the above embodiment (FIG. 2), the valve timing fixing mechanism 40 is such that the first fixing pin 51 and the second fixing pin 61 move in the axial direction with respect to the vane 35A. , 61 can be changed as follows. That is, the valve timing fixing mechanism 40 can be configured such that at least one of the first fixing pin 51 and the second fixing pin 61 protrudes and accommodates in the radial direction with respect to the vane 35A. In this case, the engagement corresponding to the first engagement groove 56 and the engagement corresponding to the second engagement groove 66 corresponding to the operation of the first fixing pin 51 and the second fixing pin 61 with respect to the vane 35A. At least one of the grooves is formed in the housing rotor 31.

  In the above embodiment (FIG. 4), the valve timing VT fixed by the valve timing fixing mechanism 40 is set to the intermediate angle phase VTmdl. Instead, other valve timing VT is set by the valve timing fixing mechanism 40. It can also be set as a fixed valve timing VT.

  -The structure of the control apparatus of the variable valve apparatus used as the application object of this invention is not restricted to the structure illustrated in the said embodiment. That is, the present invention can be applied to a control device for a variable valve operating apparatus having any configuration as long as it is a control apparatus for a variable valve operating apparatus having a phase changing mechanism and a phase fixing mechanism. Also in that case, the effect according to the effect of the above embodiment can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Accelerator pedal, 10 ... Engine main body, 11 ... Cylinder block, 12 ... Cylinder head, 13 ... Oil pan, 14 ... Combustion chamber, 15 ... Crankshaft, 20 ... Variable valve gear, 21 ... Intake Valve, 22 ... Intake camshaft, 23 ... Exhaust valve, 24 ... Exhaust camshaft, 30 ... Valve timing change mechanism (phase change mechanism), 31 ... Housing rotor, 32 ... Housing body, 32A ... Partition wall, 33 ... Sprocket, 34 ... cover, 35 ... vane rotor, 35A ... vane, 36 ... storage chamber, 37 ... advance chamber, 38 ... retard chamber, 40 ... valve timing fixing mechanism (phase fixing mechanism), 50 ... first fixing mechanism, 51 ... First fixing pin, 52 ... first fixing spring, 53 ... first fixing chamber, 54 ... first release chamber, 55 ... first spring chamber, 56 ... first engaging groove, 56A ... 1st lead angle end, 56B ... 1st retard angle end, 56C ... 2nd retard angle end, 57 ... 1st lower step groove, 58 ... 1st upper step groove, 60 ... 2nd fixing mechanism, 61 ... 2nd fixation Pin 62 62 Second fixing spring 63 Second fixing chamber 64 Second releasing chamber 65 Second spring chamber 66 Second engaging groove 66A Second advance end 66B Second 3 retard end, 66C ... 4th retard end, 67 ... 2nd lower groove, 68 ... 2nd upper groove, 70 ... hydraulic mechanism, 71 ... oil pump, 72 ... oil control valve, 73 ... oil switching Valve 74, hydraulic oil passage, 75 ... phase change oil passage, 76 ... phase-fixed oil passage, 80 ... control device, 81 ... electronic control device, 82 ... crank position sensor, 83 ... cam position sensor, 84 ... cooling water temperature Sensor, 85 ... accelerator position sensor.

Claims (9)

A control device for a variable valve gear of an internal combustion engine including a hydraulic phase change mechanism that changes valve timing and a phase lock mechanism that fixes valve timing to a specific phase, and controls the operation of the phase change mechanism In the control device for the variable valve operating device,
An operation state of the phase change mechanism in which the valve timing is fixed to the specific phase is set to a phase fixed state, an operation state of the phase change mechanism capable of changing the valve timing is set to a phase release state, and the phase The range in which the valve timing can be changed when the change mechanism is in the phase release state is set as a changeable range, the temperature of the hydraulic oil of the phase change mechanism is set as the oil temperature, and a period for limiting the changeable range is a limited period. And a state where the oil temperature is within a predetermined temperature range as a predetermined oil temperature,
When the valve timing is advanced, the operation speed of the phase change mechanism is learned, and limit control is performed to change at least one of the changeable range and the limit period according to the learned operation speed of the phase change mechanism. Yes,
The specific phase is a phase between a most retarded phase and a most advanced angle phase;
Of the range from the most retarded phase to the specific phase, a predetermined phase on the retarded side with respect to the specific phase is set as a retarded side limit phase, and the range from the most advanced angle phase to the specific phase A predetermined phase on the advance side of the specific phase is set as an advance side limit phase, a range from the specific phase to the retard side limit phase is set as a retard side limit range, and the advance phase side limit from the specific phase The range up to the phase is an advance side limit range, and the changeable range includes the retard side limit range and the advance side limit range,
For each operation speed of the phase change mechanism learned, the size of the retard side limit range is made smaller than the size of the advance side limit range,
In the restriction control, the changeable range is set to the retard side restriction range and the advance side restriction range at the predetermined oil temperature . In the control apparatus of the variable valve operating apparatus according to claim 1,
When the valve timing starts to change, the operation speed of the phase change mechanism is learned. In the control apparatus of the variable valve operating apparatus according to claim 1 or 2,
Control of the variable valve operating mechanism that learns the operation speed of the phase change mechanism when the operation state of the phase change mechanism is changed from the phase fixed state to the phase release state in accordance with an engine operating state. apparatus. In the control apparatus of the variable valve operating apparatus according to any one of claims 1 to 3,
When learning the operation speed of the phase change mechanism, selecting a supply / discharge mode for driving the phase change mechanism at an operation speed equal to or higher than a predetermined operation speed as a supply / discharge mode of the hydraulic oil to / from the phase change mechanism. A control device for a variable valve operating device. In the control apparatus of the variable valve operating apparatus according to any one of claims 1 to 4,
A control apparatus for a variable valve operating apparatus, wherein an operation speed of the phase change mechanism is learned in consideration of a rotation speed of the internal combustion engine. In the control apparatus of the variable valve operating apparatus according to any one of claims 1 to 5 ,
Prior Symbol limit control is smaller than the size of the variable range when the operation speed of the phase changing mechanism has learned the magnitude of the variable range when the operating speed of the learned the phase change mechanism is small is large A control device for a variable valve operating device. In the control apparatus of the variable valve operating apparatus according to claim 6 ,
Prior Symbol limit control, the size of the retard angle side limit range when the operation speed of the phase changing mechanism has learned the size of the retard angle side limit range when the operating speed of the learned the phase change mechanism is small is large A control device for a variable valve operating device, characterized in that the control device is made smaller. In the control apparatus of the variable valve operating apparatus according to claim 6 ,
Prior Symbol limit control, the time the operating speed of the learned said retard side limit range when the operation speed of the phase changing mechanism is small and the advance side limits of the learned magnitude the phase change mechanism is large A control apparatus for a variable valve operating system, characterized in that it is smaller than the retard angle limit range and the advance angle limit range. In the control apparatus of the variable valve operating apparatus according to any one of claims 1 to 5 ,
In the restriction control, the variable valve operating characterized in that the restriction period when the learned operation speed of the phase change mechanism is low is made longer than the restriction period when the learned operation speed of the phase change mechanism is large. Control device for the device.