JP2004239209A - Valve timing control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve timing control device of an internal combustion engine placed in a variable valve timing mechanism having a locking mechanism and allowing for suitable suppression of lock release error. <P>SOLUTION: The valve timing control device for controlling the variable valve timing mechanism having the locking mechanism calculates a waiting time WAT based on the temperature of coolant water if it receives timing advance request immediately after engine start during the operation of the locking mechanism. Then, when a time after timing advance request AT reaches the waiting time WAT, the control device actually starts controlling the timing advance. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a valve timing control device for an internal combustion engine that variably controls the valve timing according to the operating state of the internal combustion engine.
[0002]
[Prior art]
In such a valve timing control device, the valve timing of a valve that is opened and closed by the camshaft is changed by changing the relative rotation phase of the camshaft with respect to the crankshaft that is the output shaft of the internal combustion engine. I have. An example of such a valve timing control device is a vane type valve timing control device. The vane type valve timing control device is, for example, a housing that is drivingly connected to a crankshaft, and is rotatably disposed in the housing, and partitions the inside of the housing into an advance pressure chamber and a retard pressure chamber. A vane body connected to the camshaft. Then, by supplying hydraulic oil to the advance pressure chamber or the retard pressure chamber, the housing and the vane body rotate relatively, and finally the relative rotation phase of the camshaft with respect to the crankshaft, that is, the valve timing is changed. You. When the valve timing is maintained, the supply and discharge of the hydraulic oil to the advance pressure chamber and the retard pressure chamber are stopped, and the pressure of the hydraulic oil in each pressure chamber is equalized.
[0003]
By the way, when the engine is started, a sufficient amount of hydraulic oil cannot be supplied by the oil pump, so that the pressure of the hydraulic oil supplied to each of the pressure chambers is lower than that in the normal operation. Here, since the reaction torque generated when the camshaft drives the valve to open and close acts on the vane body, the vane body responds to the change in the reaction torque in such a situation where the pressure of the hydraulic oil becomes low. And it becomes difficult to maintain the valve timing constant. Further, the vane body may collide with the inner wall of the housing and generate a tapping sound.
[0004]
Thus, many vane-type valve timing control devices in recent years have a lock mechanism that regulates the relative rotation between the housing and the vane body when the engine is started. The lock mechanism includes, for example, a lock pin slidably provided on the vane body, and a lock hole provided on the inner wall of the housing and into which the tip of the lock pin is inserted. Then, when the engine is stopped or the like where the pressure of the hydraulic oil is low, the tip of the lock pin is inserted into the lock hole. Thereby, the relative rotation between the housing and the vane body is restricted.
[0005]
Further, the lock mechanism is provided with a pressure chamber for unlocking, and a pressure for pressing the lock pin in a direction to separate from the lock hole is introduced into the pressure chamber from each of the pressure chambers.
[0006]
Then, after the engine is started, a sufficient supply of hydraulic oil by the oil pump becomes possible, and when the pressure of at least one of the pressure chambers is sufficiently increased, the pressure of the unlocking pressure chamber is also increased, and the lock pin is released. The lock is released from the lock hole, and the regulation of the relative rotation between the housing and the vane body is released. When the regulation of the relative rotation is released in this way, the relative rotation between the housing and the vane body becomes possible, and the valve timing is changed based on the pressure adjustment between the retard pressure chamber and the advance pressure chamber. Become.
[0007]
Here, since the release of the lock pin is performed by the hydraulic pressure of the hydraulic oil, a malfunction may occur in the lock mechanism depending on the state of the hydraulic pressure. For example, when the engine is started, the oil pump is started from a stopped state, so that the pump discharge pressure may temporarily rise sharply and the lock pin may be forcibly released. Therefore, in the device described in Patent Document 1, when the engine is started, the supply of the hydraulic oil to both of the pressure chambers is shut off, so that the malfunction of the lock mechanism caused by a temporary sudden increase in the pump discharge pressure is suppressed. I have to.
[0008]
[Patent Document 1]
JP 2001-41012 A
[0009]
[Problems to be solved by the invention]
By the way, the malfunction of the lock mechanism is not limited to the one described above. That is, when the valve timing is changed in a state in which the hydraulic pressure of the hydraulic oil is low, such as when the pressure in the pressure chambers is reduced due to leakage of the hydraulic oil from each pressure chamber or when the engine is started, the lock is locked. Before the pin is released, the relative rotation between the housing and the vane body may be started. In this case, the lock pin is pressed against the side wall of the lock hole or the like, so that the lock is not released, and there is a possibility that the malfunction of the valve timing device may be caused. The conventional apparatus described above cannot cope with such a problem, and there is still room for improvement in this respect.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a variable valve timing mechanism having a lock mechanism, and a valve for an internal combustion engine that can appropriately suppress occurrence of lock release failure. It is to provide a timing control device.
[0011]
Means for achieving the above object and the effects thereof will be described below.
According to the first aspect of the present invention, first and second rotating bodies capable of changing a valve timing of an internal combustion engine by relatively rotating, and a rotational phase of the second rotating body with respect to the first rotating body. First and second pressure chambers to which a working fluid for changing the pressure is supplied, and relative rotation of these rotators in a predetermined rotation phase corresponding to the valve timing maximum control position of the first and second rotators And a lock mechanism for releasing the restriction based on the fluid pressure supplied to the first and second pressure chambers. When the phase is changed, one of the first and second pressure chambers that maintains the valve timing maximum control position is a parameter for estimating the fluid pressure state in the pressure chamber. After supplying the working fluid until a predetermined time has elapsed which is variably set based on the data, and its gist to supply the other pressure chamber to the working fluid.
[0012]
According to this configuration, prior to the phase change from the valve timing maximum control position at which the relative rotation is restricted by the lock mechanism of the first and second rotating bodies, the pressure chamber that maintains the control position, The working fluid is supplied to one of the pressure chambers, which is a pressure chamber on the side that is relatively rotated in the direction opposite to the direction in which the rotation phase is to be changed, for a predetermined time. Thus, a certain amount of fluid pressure is applied to the lock mechanism prior to the phase change. When the phase is changed, the fluid pressure in the other pressure chamber acts on the lock mechanism in addition to the preload. Therefore, the regulation of the relative rotation by the lock mechanism is quickly released. Here, the predetermined time for supplying the fluid pressure to the one pressure chamber is variably set based on a parameter for estimating the fluid pressure state in the pressure chamber. Therefore, it is possible to suitably set the time for sufficiently applying the preload necessary for releasing the lock mechanism, and it is possible to appropriately suppress the occurrence of lock release failure.
[0013]
Further, prior to the phase change, the working fluid is supplied to the pressure chamber that maintains the control position, so that the relative rotation operation of the first and second rotating bodies after the phase change is started becomes gentle. Also, it is easy to secure the release time of the lock mechanism.
[0014]
According to a second aspect of the present invention, in the valve timing control device for an internal combustion engine according to the first aspect, a parameter for estimating a fluid pressure state in the pressure chamber is a viscosity of a working fluid or a correlation value thereof. And
[0015]
When the working fluid is supplied to the pressure chamber that maintains the maximum control position, the fluid pressure in the pressure chamber increases. The manner in which the fluid pressure rises at this time changes depending on the viscosity of the working fluid. Therefore, in the configuration of the second aspect, the time for supplying the working fluid to the one pressure chamber is variably set based on the viscosity of the working fluid or a correlation value thereof. Therefore, the supply time of the working fluid to the one pressure chamber, which is performed prior to the phase change, can be appropriately set, and the standby time until the phase change is started can be appropriately set. Become.
[0016]
According to a third aspect of the present invention, in the valve timing control device for an internal combustion engine according to the second aspect, when the viscosity of the working fluid or a correlation value thereof is equal to or more than a predetermined value, the viscosity increases with the increase of the viscosity. The gist is that the predetermined time is set to increase.
[0017]
According to this configuration, as the viscosity of the working fluid increases to a predetermined value or more, the fluidity of the working fluid decreases, and as the supply amount of the working fluid per unit time to the one pressure chamber decreases, the pressure chamber increases. The time for supplying the working fluid to is increased. Therefore, the fluid pressure in the one pressure chamber can be reliably increased in response to the change in the viscosity of the working fluid, and the lock mechanism can be reliably released.
[0018]
According to a fourth aspect of the present invention, in the valve timing control apparatus for an internal combustion engine according to the second or third aspect, when the viscosity of the working fluid or a correlation value thereof is equal to or less than a predetermined value, the viscosity is reduced. The gist is that the predetermined time is set to increase.
[0019]
Generally, the lower the viscosity of the working fluid, the lower the fluid pressure in the flow path. Therefore, in the configuration according to the fourth aspect, as the viscosity of the working fluid decreases below a predetermined value and the fluid pressure in the flow path circuit decreases, the time for supplying the working fluid to the one pressure chamber increases. I am trying to do it. That is, as the fluid pressure decreases, more working fluid is supplied to the one pressure chamber. Therefore, the fluid pressure in the one pressure chamber can be reliably increased in response to the change in the viscosity of the working fluid, and the lock mechanism can be reliably released.
[0020]
According to a fifth aspect of the present invention, in the valve timing control device for an internal combustion engine according to the first aspect, the parameter for estimating the fluid pressure state in the pressure chamber is an engine stop time before the engine is started. Make a summary.
[0021]
When the operation of the internal combustion engine is stopped, the pump that supplies the working fluid to the first and second pressure chambers is also stopped. Therefore, the fluid pressure in the first and second pressure chambers gradually decreases while the engine is stopped, and the fluid pressure when the lock mechanism is released at the time of starting the engine becomes insufficient. Therefore, in the configuration of the fifth aspect, the time for supplying the working fluid to the one pressure chamber is variably set based on the engine stop time before the engine is started. Therefore, the supply time of the working fluid to the one pressure chamber, which is performed prior to the phase change, can be appropriately set, and the standby time until the phase change is started can be appropriately set. Become.
[0022]
According to a sixth aspect of the invention, in the valve timing control device for an internal combustion engine according to the fifth aspect, the predetermined time is set to be longer as the engine stop time becomes longer.
[0023]
As described above, when the operation of the internal combustion engine is stopped, the pump that supplies the working fluid to the first and second pressure chambers is also stopped. Therefore, the first and second pumps are gradually stopped while the engine is stopped. The fluid pressure in the pressure chamber decreases, and the fluid pressure when releasing the lock mechanism at the time of starting the engine becomes insufficient. Therefore, in the configuration according to the sixth aspect, the longer the engine stop time is, the longer the time for supplying the working fluid to the one pressure chamber is. Therefore, the fluid pressure that has dropped during the engine stop time can be reliably increased, and the lock mechanism can be reliably released.
[0024]
The invention according to claim 7, wherein the first and second rotating bodies capable of changing the valve timing of the internal combustion engine by relatively rotating, and the rotational phase of the second rotating body with respect to the first rotating body. The first and second pressure chambers to which the working fluid for changing the pressure is supplied, and the relative rotation of these rotators in a rotation phase corresponding to the valve timing maximum control position of the first and second rotators. A lock mechanism that regulates and releases the regulation based on fluid pressure supplied to at least one of the first and second pressure chambers, and a pump that supplies working fluid to the first and second pressure chambers. In a valve timing control device for an internal combustion engine having a pressure sensor for detecting a discharge pressure, a value detected by the pressure sensor becomes equal to or higher than an allowable pressure set based on a viscosity of the working fluid or a correlation value thereof. Supplying the working fluid to one of the first and second pressure chambers on the side that maintains the valve timing maximum control position, and then supplying the working fluid to the other pressure chamber. Make a summary.
[0025]
In this configuration, the working fluid is supplied to the one pressure chamber until the discharge pressure of the pump detected by the pressure sensor becomes equal to or higher than the allowable pressure. Here, the discharge pressure of the pump detected by the pressure sensor when the working fluid is supplied to the one pressure chamber, and the fluid pressure in the same pressure chamber differ depending on the viscosity of the working fluid. Therefore, in the configuration of the seventh aspect, the allowable pressure is set based on the viscosity of the working fluid or a correlation value thereof. Therefore, a suitable value corresponding to the above-described fluid pressure difference is set as the allowable pressure, and the supply of the working fluid to the pressure chamber, which is performed prior to the phase change, can be suitably performed. As a result, it is possible to appropriately suppress occurrence of lock release failure.
[0026]
The invention according to claim 8 is the valve timing control device for an internal combustion engine according to claim 7, wherein the allowable pressure is set higher as the viscosity of the working fluid or a correlation value thereof increases. Make a summary.
[0027]
As the viscosity of the working fluid increases, the fluid pressure in the flow path increases, but the fluidity also decreases.Therefore, the fluid pressure in the pressure chamber that maintains the control position and the fluid detected by the pressure sensor The difference from the pressure increases. Therefore, in the configuration of the eighth aspect, the allowable pressure is increased with an increase in the viscosity of the working fluid or a correlation value thereof. Therefore, even in a situation where the fluidity decreases with an increase in the viscosity, the working fluid is forcibly supplied to the pressure chamber at a higher pressure, so to speak, so that the fluid pressure in the pressure chamber is reliably increased. Thus, the lock mechanism can be reliably released.
[0028]
According to a ninth aspect of the present invention, in the valve timing control device for an internal combustion engine according to any of the second to fourth, seventh, and eighth aspects, the gist is that the correlation value is a temperature of a working fluid.
[0029]
The viscosity of a working fluid tends to decrease as the fluid temperature increases. According to the configuration described in claim 9 in which attention is paid to such a tendency, the viscosity of the working fluid can be estimated based on the temperature of the working fluid, and the viscosity can be estimated based on any of claims 2 to 4, 7, and 8. The effect of the invention can be obtained.
[0030]
According to a tenth aspect, in the valve timing control device for an internal combustion engine according to any of the second to fourth, seventh, and eighth aspects, the gist is that the correlation value is a cooling water temperature.
[0031]
The viscosity of the working fluid tends to decrease as the cooling water temperature of the internal combustion engine increases. According to the configuration described in claim 10 in which attention is paid to such a tendency, the cooling water temperature, which is a detection value of a water temperature sensor generally provided in an internal combustion engine, is used as a correlation value for the viscosity of the working fluid. Can be Therefore, the operation and effect according to any one of claims 2 to 4, 7, and 8 can be obtained without separately providing a sensor for detecting the viscosity of the working fluid.
[0032]
According to an eleventh aspect of the present invention, in the valve timing control device for an internal combustion engine according to any one of the second to fourth, seventh, and eighth aspects, the correlation value is a cooling water temperature and an intake air temperature. .
[0033]
The influence of the intake air temperature on the change of the cooling water temperature, in other words, the influence of the outside air temperature on the change of the cooling water temperature is smaller than the influence of the intake air temperature on the change of the viscosity of the working fluid, in other words, the change of the temperature of the working fluid. Therefore, for example, when the intake air temperature is low, a situation in which the temperature of the working fluid is low while the cooling water temperature is high is also assumed. In this regard, according to the configuration of the eleventh aspect, a value taking into consideration not only the cooling water temperature but also the intake air temperature is used as a value having a correlation with the viscosity of the working fluid. Therefore, the accuracy of the correlation with the viscosity of the working fluid is further improved, and the operation and effect according to any one of claims 2 to 4, 7, and 8 naturally have high accuracy. In this case as well, the cooling water temperature and the intake air temperature, which are values detected by the water temperature sensor and the intake air temperature sensor generally provided in the internal combustion engine, are used instead of the viscosity of the working fluid. Therefore, the operation and effect according to any one of claims 2 to 4, 7, and 8 can be obtained without separately providing a sensor for detecting the viscosity of the working fluid.
[0034]
BEST MODE FOR CARRYING OUT THE INVENTION
(1st Embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to FIGS.
[0035]
FIG. 1 shows both the structure of the variable valve timing mechanism of the valve timing control device of the present embodiment and the hydraulic circuit structure of the control device.
As shown in FIG. 1, the variable valve timing mechanism includes a substantially annular housing 103 as a first rotating body and a vane body 101 as a second rotating body housed therein. Have. The vane body 101 is connected to a camshaft 130 that drives an intake valve, and the housing 103 is connected to a cam pulley 105 that rotates in synchronization with a crankshaft, which is an engine output shaft, so as to be integrally rotatable. In this example, the camshaft rotates clockwise in FIG.
[0036]
A plurality of vanes 102 extending in the radial direction are formed on the outer periphery of the vane body 101. A plurality of recesses 104 extending in the circumferential direction are formed on the inner periphery of the housing 103, and the vanes 102 are disposed in the respective recesses 104. In each recess 104, an advanced pressure chamber 106 as a first pressure chamber and a retard pressure chamber 107 as a second pressure chamber are formed by being partitioned by the vanes 102, respectively. Although FIG. 1 shows two vanes 102 and two recesses 104, the numbers may be changed as appropriate.
[0037]
The advance pressure chamber 106 and the retard pressure chamber 107 are respectively connected to a hydraulic control valve 120 via appropriate oil passages. The hydraulic control valve 120 is connected to an oil pump 121 which is drivingly connected to a crankshaft. A working oil, which is a working fluid to be sent, is supplied. The hydraulic control valve 120 is a valve that can adjust the amount of hydraulic oil supplied to the advance pressure chamber 106 or the retard pressure chamber 107 according to the duty ratio of the voltage applied to the valve. The hydraulic control valve 120 operates based on a command signal from the electronic control unit 122 to supply hydraulic oil into the advance pressure chamber 106 or the retard pressure chamber 107 or to operate the advance oil chamber 106 or the retard pressure chamber 107. Let it drain from inside. The vane 102 has a desired relative rotation phase in the recess 104 due to a difference in fluid pressure between the advance pressure chamber 106 and the retard pressure chamber 107 formed on both side surfaces thereof, that is, a difference in oil pressure. Is set to the phase of As a result, the vane body 101 is relatively rotated with respect to the housing 103, and the relative rotation phase of the cam shaft 130 with respect to the cam pulley 105 is changed, so that the valve timing of the intake valve is changed.
[0038]
Note that the valve timing control is specifically performed as follows.
Parameters representing the engine operating state such as the cooling water temperature THW detected by the water temperature sensor 10, the engine rotation speed detected by the crank angle sensor, and the throttle valve opening detected by the throttle sensor are input to the electronic control unit 122. Is done. Then, the electronic control unit 122 calculates an appropriate valve timing according to the engine operating state based on these parameters, and calculates a target value of the relative rotation phase of the vane body 101 corresponding thereto. If the target value is different from the current phase, the electronic control unit 122 discharges the hydraulic oil from one of the advance pressure chamber 106 and the retard pressure chamber 107 and supplies the hydraulic oil to the other. The operation of the hydraulic control valve 120 is controlled as described above. The vane body 101 relatively rotates with respect to the housing 103 in accordance with the resulting pressure difference between the advance pressure chamber 106 and the retard pressure chamber 107, and the valve timing is adjusted.
[0039]
Then, as a result of such adjustment, when the target value matches the current phase, the electronic control unit 122 controls the hydraulic control valve 120 to stop supply and discharge of hydraulic oil to the advance pressure chamber 106 and the retard pressure chamber 107. To control the operation. As a result, the pressure in the advance pressure chamber 106 and the pressure in the retard pressure chamber 107 are maintained uniformly, and the relative rotation phase of the vane body 101 is also maintained.
[0040]
In this variable valve timing mechanism, the vane body 101 can be relatively rotated in a range from a phase in which the vane 102 contacts one side wall of the concave portion 104 to a phase in contact with the opposite side wall of the concave portion 104. Has become. That is, the range of the phase in which the relative rotation is possible is the control range of the rotation phase in the valve timing control device. Hereinafter, the position when the vane body 101 is relatively rotated in the most retarded direction (the direction opposite to the rotation direction of the camshaft 130), that is, the maximum control position on the retard side of the above-described control range is referred to as the “most retarded position. " This position is set as the initial position when the operation of the hydraulic control valve 120 is not controlled by the electronic control unit 122, that is, the position when the engine is stopped. On the other hand, the position at the time of relative rotation in the most advanced direction (the rotation direction of the camshaft 130), that is, the maximum control position on the advanced side of the control range is referred to as "most advanced position".
[0041]
As described above, in the valve timing control device of the present embodiment, the vane body 101 is moved from the “most retarded position” to the “most advanced position” based on the pressure control in the advanced pressure chamber 106 and the retarded pressure chamber 107. Relative rotation in the range up to. The relative rotation changes the relative rotation phase of the camshaft 130 with respect to the crankshaft, and makes the opening / closing valve timing (valve timing) of the intake valve that is driven to open and close with the rotation of the camshaft 130 variable.
[0042]
In addition, the variable valve timing mechanism of the present embodiment is provided with a lock mechanism that regulates the relative rotation of the vane body 101 when the pressure drops such as when the engine is started.
That is, as shown in FIG. 1, one of the vanes 102 is formed with a stepped accommodation hole 30 extending parallel to the axial direction of the camshaft 130, and a space inside the accommodation hole 30 has A lock pin 31 is provided so as to be able to slide back and forth.
[0043]
The lock pin 31 is moved from the position shown in FIG. 2 to the position shown in FIG. 3 in a state where the outer peripheral surface is in sliding contact with the inner peripheral surface of the accommodation hole 30 as shown in the sectional structure of FIGS. Are moved in the axial direction of the camshaft 130. The lock pin 31 is urged toward the cam pulley 105 by a coil spring 33. At the end of the lock pin 31, a stepped portion 31a having an enlarged diameter is formed, and between the stepped portion 31a and the stepped portion 30a of the accommodation hole 30, an unlocking pressure chamber as an annular space is formed. 37 are formed. The unlocking pressure chamber 37 is connected to the advance pressure chamber 106 through the advance oil passage 35 formed in the vane 102, and the pressure in the advance pressure chamber 106 is transmitted. ing.
[0044]
On the other hand, the housing 103 has a lock hole 32 into which the lock pin 31 can be inserted when the vane body 101 is located at the most retarded position. As shown in FIG. 2, when the lock pin 31 is inserted into the lock hole 32 by the urging force of the coil spring 33, the vane body 101 is mechanically fastened to the housing 103, and the relative rotation thereof is restricted (locked). ) Will be.
[0045]
The space formed by the lock hole 32 and the tip of the lock pin 31 is a lock release pressure chamber 38, and a retard side oil passage 36 formed in a sliding contact surface between the vane 102 and the housing 103. Is connected to the retard pressure chamber 107 so that the pressure in the retard pressure chamber 107 is transmitted.
[0046]
The pressure of the hydraulic oil in the unlocking pressure chambers 37 and 38 acts in a direction to release the lock pin 31 from the housing hole 30. Therefore, when the pressure in one or both of the advance pressure chamber 106 and the retard pressure chamber 107 increases and the pressure in the unlocking pressure chambers 37 and 38 connected thereto increases sufficiently, as shown in FIG. Then, the lock pin 31 moves in a direction to separate from the accommodation hole 30, and the regulation (lock) of the relative rotation is released.
[0047]
On the other hand, when the operation of the hydraulic control valve 120 is not controlled, the oil circuit is configured such that the oil pump 121 and the retard pressure chamber 107 communicate with each other. Therefore, when the hydraulic control valve 120 is not operating at the time of starting the engine, hydraulic oil is supplied from the oil pump 121 to the retard pressure chamber 107.
[0048]
Thus, in the valve timing control device of the present embodiment, when the pressure drops immediately after the start of the engine, the relative rotation of the vane body 101 is regulated (locked) at the most retarded position so that the oil pump 121 can supply sufficient hydraulic oil. Then, the regulation of the relative rotation is released, so that the valve timing control can be performed.
[0049]
By the way, when the engine is started, since the oil pump 121 cannot supply sufficient hydraulic oil, the lock pin 31 is released from the lock hole 32 in such a valve timing control device when an advance request is made immediately after the engine is started. Before that, the relative rotation between the housing 103 and the vane body 101 may be started. In this case, the lock pin 31 is pressed against the side wall of the lock hole 32 or the like, so that the lock mechanism may not be released properly, which may cause a malfunction of the variable valve timing mechanism.
[0050]
Therefore, in the valve timing control device according to the present embodiment, when an advance request is made immediately after the engine is started, hydraulic oil is supplied to the retard pressure chamber 107 and hydraulic oil is supplied to the unlocking pressure chamber 38 for a predetermined time. I do. After applying a preload in the direction to release the lock pin 31, hydraulic oil is supplied to the advance pressure chamber 106, so that the hydraulic pressure is reliably applied to the lock release pressure chambers 37 and 38, and the lock is released. The mechanism can be released without fail.
[0051]
Here, if the predetermined time for supplying the hydraulic oil to the retard pressure chamber 107 is too short, the hydraulic pressure in the retard pressure chamber 107 becomes insufficient, so that the lock pin 31 can be released. Insufficient preload can not be applied. If the predetermined time is too long, a sufficient preload can be applied to the lock pin 31, but the time from when the advance angle request is made to when the hydraulic oil is actually supplied to the advance pressure chamber 106 becomes long. This causes unnecessary waiting time. If such an unnecessarily long standby time is set, for example, the following inconvenience may occur.
[0052]
That is, in recent years, hybrid vehicles equipped with an electric motor and an internal combustion engine as drive sources have been put to practical use. In this hybrid vehicle, the drive source is switched according to a vehicle running state suitable for the output characteristics of the electric motor and a vehicle running state suitable for the output characteristics of the internal combustion engine. Here, even when the vehicle is running using the electric motor as a drive source, the crankshaft of the internal combustion engine is rotating, and the intake air is compressed in the cylinder of the engine. The load resulting from the compression of the intake air becomes the load resistance of the electric motor. Therefore, when the vehicle is driven by the electric motor, the closing timing of the intake valve of the internal combustion engine is changed to the vicinity of the compression top dead center to substantially reduce the compression stroke and reduce the load. On the other hand, when the vehicle is driven by the internal combustion engine, the closing timing of the intake valve is advanced to secure a sufficient compression stroke, and to obtain an output torque necessary for the vehicle to run. Conversely, a sufficient output torque cannot be obtained unless the intake valve is advanced immediately after the engine is started. Therefore, if the above-mentioned waiting time is unnecessarily long, the output torque reduction time immediately after the start of the engine becomes long. Of course, not only in a hybrid vehicle but also in a vehicle equipped with only an internal combustion engine as a drive source, it is preferable that the advance control be performed as soon as possible after the advance request is made.
[0053]
Therefore, in the present embodiment, the predetermined time for supplying the hydraulic oil to the retard pressure chamber 107 is variably set based on a parameter for estimating the oil pressure state in the retard pressure chamber 107, so that the lock mechanism is released. The time for applying the necessary preload without excess or deficiency is set to suppress the occurrence of lock release failure.
[0054]
Hereinafter, the details of the advance waiting process in this embodiment will be described with reference to FIGS. 4 and 5.
FIG. 4 shows a processing procedure of the electronic control device 122 in such advance standby processing, which is executed at the time of starting the engine.
[0055]
When this process is started, first, the cooling water temperature THW is read (S100). Next, it is determined whether an advance request has been made from the electronic control unit 122 (S110). If the advance request has not been made (NO in S110), the present process ends.
[0056]
On the other hand, when the advance angle is requested (YES in S110), the standby time WAT is obtained from the standby time map illustrated in FIG. 5 based on the cooling water temperature THW. As shown in FIG. 5, the standby time map is set so that the standby time becomes shorter as the cooling water temperature THW increases until the temperature reaches a certain predetermined temperature. The standby time is set to be longer as the cooling water temperature THW becomes higher. In other words, when the cooling water temperature THW is equal to or lower than the predetermined value, the standby time WAT is set to increase as the cooling water temperature THW decreases. Further, when the cooling water temperature THW is equal to or higher than a predetermined value, the standby time WAT is set to increase as the cooling water temperature THW increases, for the following reasons.
[0057]
Generally, as the cooling water temperature THW decreases, the temperature of the hydraulic oil tends to decrease. As the temperature of the hydraulic oil decreases, the viscosity of the hydraulic oil increases, the fluidity of the hydraulic oil decreases, and the supply amount of the hydraulic oil to the retard pressure chamber 107 per unit time decreases. Therefore, when the cooling water temperature THW is in a region equal to or lower than a predetermined value, by setting the standby time WAT to be longer as the cooling water temperature THW becomes lower, more hydraulic oil is supplied to the retard pressure chamber 107. As a result, the oil pressure in the retard pressure chamber 107 can be reliably increased.
[0058]
On the other hand, as the cooling water temperature THW increases, the temperature of the hydraulic oil tends to increase. As the temperature of the hydraulic oil increases, the viscosity of the hydraulic oil decreases. It is known that the lower the viscosity of the hydraulic oil is, the lower the hydraulic pressure in the oil circuit is. Therefore, when the cooling water temperature THW is in a region equal to or higher than the predetermined value, by setting the standby time WAT to be longer as the cooling water temperature THW becomes higher, more hydraulic oil is supplied to the retard pressure chamber 107. As a result, the oil pressure in the retard pressure chamber 107 can be reliably increased.
[0059]
When the standby time WAT is obtained in S120, it is next determined whether or not the post-advance angle request time AT has become equal to or longer than the standby time WAT (S130). That is, it is determined whether sufficient hydraulic oil has been supplied to the retard pressure chamber 107 and the hydraulic pressure in the retard pressure chamber 107 has increased. Here, the post-advance request time AT is an elapsed time from when the advance request is made by the electronic control device 122 to when the current process is performed, and is measured by a timer counter or the like in the electronic control device 122. ing. The comparison determination in S130 is repeatedly performed until the time AT after the advance request is equal to or longer than the standby time WAT, and when the time AT after the advance request is equal to or longer than the standby time WAT (YES in S130), the hydraulic control valve 120 , An advanced angle control signal is output, and the variable valve timing mechanism is actually advanced (S140). Then, the present process ends.
[0060]
As described above, in the present embodiment, in the variable valve timing mechanism including the lock pin 31 that is released by the oil pressure in both the retard pressure chamber 107 and the advance pressure chamber 106, when the advance request is made. First, hydraulic oil is supplied to the retard pressure chamber 107. Therefore, prior to the advance control, a preload is applied to the unlocking pressure chamber 38, and the lock pin 31 is easily released. Then, when the advance control is executed and the hydraulic oil is also supplied to the advance pressure chamber 106, the hydraulic oil is also supplied to the unlock pressure chamber 37, and the lock pin 31 is moved to the unlock pressure chamber 37. The release is ensured by the oil pressure of 38. At this time, the standby time WAT, that is, the time for supplying the hydraulic oil to the retard pressure chamber 107, is variably set in accordance with the above tendency based on the cooling water temperature THW which is correlated with the viscosity of the hydraulic oil. Therefore, the time during which the hydraulic pressure in the retard pressure chamber 107 can be reliably increased is set without excess or shortage.
[0061]
As described above, according to the valve timing control device for an internal combustion engine in the first embodiment, the following effects can be obtained.
(1) In the variable valve timing mechanism having the lock pin 31 which is released by the oil pressure in both the retard pressure chamber 107 and the advance pressure chamber 106, when an advance request is made, first the retard pressure The working oil is supplied to the chamber 107. Therefore, the lock mechanism can be reliably released.
[0062]
(2) Hydraulic oil is supplied to the retard pressure chamber 107 prior to the advance control, but the supply time is variably set based on a parameter for estimating the oil pressure state in the retard pressure chamber 107. Like that. More specifically, when hydraulic oil is supplied to the retard pressure chamber 107, the hydraulic pressure in the retard pressure chamber 107 increases, but the mode of the increase in the hydraulic pressure at this time varies depending on the viscosity of the hydraulic oil. I do. Therefore, the time for supplying the hydraulic oil to the retard pressure chamber 107 is variably set based on the coolant temperature THW, which is a correlation value of the viscosity of the hydraulic oil. Accordingly, it is possible to suitably set the supply time of the hydraulic oil to the retard pressure chamber 107 performed prior to the advance control, and thus to set a sufficient time for applying the preload necessary for releasing the lock mechanism. It can be set appropriately.
[0063]
(3) The standby time map is set such that when the cooling water temperature THW, which is a correlation value of the viscosity of the hydraulic oil, is in a region equal to or higher than a predetermined value, the standby time WAT increases as the viscosity of the hydraulic oil decreases. are doing. In addition, when the cooling water temperature THW is in a region equal to or lower than a predetermined value, the standby time WAT is set to increase as the viscosity of the hydraulic oil increases. Therefore, the hydraulic pressure in the retard pressure chamber 107 can be reliably increased in response to the change in the viscosity of the working fluid, and the lock mechanism can be reliably released.
[0064]
(4) Since hydraulic oil is supplied to the retard pressure chamber 107 prior to the advance control, the inside of the advance pressure chamber 106 and the inside of the retard pressure chamber 107 when the advance control is performed are controlled. , The relative rotation between the housing 103 and the vane body 101 is also gently performed. Therefore, as compared with the case where the relative rotation is quickly performed, the time required for releasing the lock mechanism can be easily secured, and when the hydraulic pressure is likely to decrease in the moving speed of the lock pin 31 in the release direction, Immediately after the start of the engine as described above, the lock mechanism can be reliably released.
[0065]
(5) The standby time WAT is obtained based on the cooling water temperature THW, which is a correlation value of the viscosity of the working oil, which is a parameter that can estimate the oil pressure state in the retard pressure chamber 107. Here, the cooling water temperature THW is a value detected by a water temperature sensor generally provided in an internal combustion engine. Therefore, the above-described effect can be obtained without separately providing a sensor for detecting the viscosity of the hydraulic oil.
[0066]
(6) When the engine in which the oil pressure in the oil circuit is low is started, the above-described advance standby processing is executed. Therefore, it is possible to appropriately suppress the failure of the release of the lock mechanism due to the decrease in the hydraulic pressure.
[0067]
(Second embodiment)
Next, a second embodiment of the present invention will be described.
This embodiment is basically the same as the first embodiment except that the mode of the advance waiting process is different from the first embodiment, and also has the same configuration of the variable valve timing mechanism. Therefore, hereinafter, the advance waiting process in the present embodiment will be described in detail with reference to FIGS. 6 and 7, focusing on differences from the first embodiment.
[0068]
When the operation of the internal combustion engine is stopped, the oil pump 121 is also stopped. Therefore, while the engine is stopped, the hydraulic oil in the retard pressure chamber 107 and the advance pressure chamber 106 gradually leaks, and the oil pressure in both pressure chambers also decreases. Insufficient hydraulic pressure. Thus, in the present embodiment, the time for supplying the hydraulic oil to the retard pressure chamber 107 is variably set based on the engine stop time before starting the engine.
[0069]
FIG. 6 shows a processing procedure of the electronic control unit 122 in such advance angle standby processing, which is executed at the time of starting the engine.
When this process is started, first, the engine stop time ST is read (S200). The engine stop time ST is a time from when the engine is stopped to when the engine is started, and the off / on time of the ignition switch is measured by a timer counter or the like in the electronic control unit 122. .
[0070]
Next, based on the engine stop time ST, the standby time WT is obtained from the standby time map illustrated in FIG. 7 (S210). As shown in FIG. 6, the standby time map is set such that the longer the engine stop time ST, the longer the standby time WT, for the following reason.
[0071]
That is, as described above, since the operation of the oil pump 121 is stopped while the engine is stopped, as the engine stop time ST becomes longer, the amount of hydraulic oil leaking from the retarded pressure chamber 107 or the advanced pressure chamber 106 becomes smaller. It increases and the oil pressure in both pressure chambers decreases. Therefore, the standby time map is set such that the standby time WT, which is the time during which the hydraulic oil is supplied to the retard pressure chamber 107, becomes longer as the engine stop time ST becomes longer. Hydraulic fluid can be supplied to the retard pressure chamber 107 in an amount corresponding to the amount of oil leaked from the valve. Therefore, the hydraulic pressure in the retard pressure chamber 107 can be reliably increased, and the lock mechanism can be reliably released.
[0072]
Next, it is determined whether or not a lead angle request has been made from the electronic control unit 122 (S220). If the advance request has not been made (NO in S220), the present process ends.
[0073]
On the other hand, if the advance request has been made (YES in S220), it is determined whether or not the post-engine-start time ONT has become equal to or longer than the standby time WT (S230). That is, it is determined whether sufficient hydraulic oil has been supplied to the retard pressure chamber 107 and the hydraulic pressure in the retard pressure chamber 107 has increased. Here, the post-engine-start time ONT is an elapsed time from when the engine is started to when the determination process in S220 is performed, and is measured by a timer counter or the like in the electronic control device 122. The comparison determination in S230 is repeated until the time after engine start ONT becomes equal to or longer than the standby time WT, and when the time ONT after engine start becomes equal to or longer than the standby time WT (YES in S230), the hydraulic control valve 120 Then, the advance control signal is output, and the variable valve timing mechanism is actually advanced (S240). Then, the present process ends.
[0074]
According to the valve timing control device for an internal combustion engine in the second embodiment, the following effects can be obtained.
(1) Hydraulic oil is supplied to the retard pressure chamber 107 prior to the advance control, but the supply time is variably set based on a parameter for estimating the oil pressure state in the retard pressure chamber 107. Like that. More specifically, the standby time WT, which is the supply time, is variably set so that the hydraulic oil leaked from the retard pressure chamber 107 can be replenished within the engine stop time ST. Therefore, it is possible to suitably set the supply time of the hydraulic oil to the retard pressure chamber 107 performed prior to the advance control, and to appropriately set the standby time until the advance control is started. Will be able to
[0075]
(2) The standby time WT is set to be longer as the engine stop time ST becomes longer. Therefore, the oil pressure in the retard pressure chamber 107, which has been reduced during the engine stop time ST, can be reliably increased, and the lock mechanism can be reliably released.
[0076]
(Third embodiment)
Next, a third embodiment of the invention will be described.
This embodiment is different from the first embodiment in the aspect of the advance waiting process, and as shown in FIG. 8, the hydraulic pressure between the hydraulic control valve 120 and the oil pump 121, that is, the oil pump 121 The second embodiment is basically the same as the first embodiment except that a pressure sensor 140 for detecting the discharge pressure is provided. Therefore, hereinafter, the advance waiting process in the present embodiment will be described in detail with reference to FIGS. 9 and 10, focusing on differences from the first embodiment.
[0077]
Generally, as the cooling water temperature THW decreases, the temperature of the hydraulic oil tends to decrease. As the temperature of the hydraulic oil decreases, the viscosity of the hydraulic oil increases and the fluidity of the hydraulic oil decreases. Therefore, in the initial stage of the supply of the hydraulic oil to the retard pressure chamber 107, a difference is generated between the oil pressure P detected by the pressure sensor 140 and the oil pressure in the retard pressure chamber 107, and this difference is caused by the difference of the hydraulic oil. The higher the viscosity, the larger. Therefore, in the present embodiment, the advance angle control is performed after the hydraulic pressure P becomes equal to or higher than the allowable pressure OKP that is increased with an increase in the viscosity of the hydraulic oil.
[0078]
FIG. 9 shows a processing procedure of the electronic control device 122 in such advance waiting processing, which is executed at the time of starting the engine.
When this process is started, first, the cooling water temperature THW is read (S300). Next, it is determined whether or not a lead angle request has been made from the electronic control unit 122 (S310). If the advance request has not been made (NO in S310), this process ends.
[0079]
On the other hand, if the advance request is made (YES in S310), the allowable pressure OKP is obtained from the allowable pressure calculation map illustrated in FIG. 10 based on the coolant temperature THW (S320). This allowable pressure OKP is a hydraulic pressure used for determination when switching the supply of the hydraulic oil to the retard pressure chamber 107 to the supply of the hydraulic oil to the advance pressure chamber 106, and can sufficiently secure the above-described preload. Value. Further, as shown in FIG. 10, the allowable pressure calculation map is set so that the higher the cooling water temperature THW, the higher the allowable pressure OKP, for the following reason.
[0080]
As described above, in the initial stage of the supply of the hydraulic oil to the retard pressure chamber 107, there is a difference between the oil pressure P detected by the pressure sensor 140 and the oil pressure in the retard pressure chamber 107. Here, when the cooling water temperature THW is low, in other words, when the viscosity of the hydraulic oil is low and its fluidity is high, the hydraulic oil is quickly supplied from the oil pump 121 to the retarded pressure chamber 107, so that the pressure difference is rapidly increased. Will be resolved. On the other hand, when the viscosity of the hydraulic oil is high and its fluidity is low, the supply of the hydraulic oil from the oil pump 121 to the retard pressure chamber 107 is delayed, so that it takes some time to eliminate the pressure difference. Therefore, as the cooling water temperature THW decreases (as the viscosity of the hydraulic oil increases), the hydraulic oil is forcibly supplied to the retard pressure chamber 107 by increasing the permissible pressure OKP, and the retard pressure chamber 107 is surely supplied. To increase the internal oil pressure.
[0081]
When the allowable pressure OKP is obtained in S320, it is next determined whether or not the oil pressure P detected by the pressure sensor 140 has become equal to or higher than the allowable pressure OKP (S330). That is, it is determined whether sufficient hydraulic oil has been supplied to the retard pressure chamber 107 and the hydraulic pressure in the retard pressure chamber 107 has increased. Then, the comparison determination in S330 is repeatedly performed until the oil pressure P becomes equal to or higher than the allowable pressure OKP. When the oil pressure P becomes equal to or higher than the allowable pressure OKP (YES in S330), the advance angle control signal is sent to the hydraulic control valve 120. Then, the variable valve timing mechanism is actually advanced (S340). Then, the present process ends.
[0082]
As described above, according to the valve timing control device for an internal combustion engine in the third embodiment, the following effects can be obtained.
(1) The allowable pressure OKP is set according to the cooling water temperature THW, in other words, according to the viscosity of the hydraulic oil. Therefore, a suitable allowable pressure OKP corresponding to the pressure difference between the oil pressure P and the oil pressure in the retard pressure chamber 107 is set, and the supply of the working oil to the retard pressure chamber 107 performed prior to the advance control is performed. It can be suitably implemented. As a result, the occurrence of insufficient release of the lock mechanism can be appropriately suppressed.
[0083]
(2) Further, the lower the cooling water temperature THW (the higher the viscosity of the hydraulic oil), the higher the allowable pressure OKP. Therefore, as the fluidity of the hydraulic oil decreases, the hydraulic oil is forcibly supplied to the retard pressure chamber 107. Therefore, the hydraulic pressure in the retard pressure chamber 107 is reliably increased, and the lock mechanism can be reliably released.
[0084]
(3) Generally, the oil pressure between the hydraulic control valve 120 and the retard pressure chamber 107 depends on the operation of the hydraulic control valve 120 and the amount of hydraulic oil between the hydraulic control valve 120 and the retard pressure chamber 107. It fluctuates under the influence. In comparison, it is known that the hydraulic pressure between the hydraulic control valve 120 and the oil pump 121 is relatively stable. The pressure sensor 140 is provided at a portion where the change in the oil pressure is relatively gentle. Therefore, the comparison judgment between the hydraulic pressure P and the allowable pressure OKP naturally becomes highly accurate.
[0085]
(Other embodiments)
The above embodiments can be modified and implemented as follows.
-You may implement combining 1st Embodiment and 2nd Embodiment. For example, the following can be performed.
[0086]
(A) The standby time WAT calculated in the first embodiment is compared with the standby time WT calculated in the second embodiment, and the standby time for which a longer time is set is adopted. Alternatively, the advance angle control may be made to wait until the standby time elapses.
[0087]
(B) The waiting time for waiting for the advance control is determined based on the increase in the oil pressure in the retard pressure chamber 107 estimated from the cooling water temperature THW and the remaining amount of hydraulic oil estimated from the engine stop time ST. You may.
[0088]
In these cases, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
-You may implement combining 1st Embodiment and 3rd Embodiment. For example, the following can be performed.
[0089]
(C) The time AT after the advance request is longer than the standby time WAT calculated in the first embodiment, and the hydraulic pressure P described in the third embodiment is the allowable pressure OKP calculated in the third embodiment. The advance control may be executed when the above is reached.
[0090]
Even in such a case, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
-You may implement combining 2nd Embodiment and 3rd Embodiment. For example, the following can be performed.
[0091]
(D) The time after engine start ONT has elapsed beyond the standby time WT calculated in the second embodiment, and the hydraulic pressure P described in the third embodiment is equal to or greater than the allowable pressure OKP calculated in the third embodiment. The advance angle control may be executed when.
[0092]
Even in such a case, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
-You may implement combining 1st-3rd embodiment. For example, the following can be performed.
[0093]
(E) The standby time WAT calculated in the first embodiment is compared with the standby time WT calculated in the second embodiment, and the standby time for which a longer time is set is adopted. When the selected standby time elapses after the advance request is made and the hydraulic pressure P described in the third embodiment becomes equal to or higher than the allowable pressure OKP calculated in the third embodiment, the advance control is performed. May be executed.
[0094]
(F) The standby time for waiting for the advance control is obtained based on the change in the oil pressure in the retard pressure chamber 107 estimated from the cooling water temperature THW and the remaining amount of hydraulic oil estimated from the engine stop time ST. When the calculated waiting time elapses after the advance request is made and the hydraulic pressure P described in the third embodiment becomes equal to or higher than the allowable pressure OKP calculated in the third embodiment, the advance control is performed. May be executed.
[0095]
Also in these cases, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
In the second embodiment, the standby time WT is obtained based on the engine stop time ST. Here, the higher the viscosity of the hydraulic oil immediately after the engine is stopped, the smaller the amount of hydraulic oil leaking from the retard pressure chamber 107 and the advance pressure chamber 106, and the lower the oil pressure in the retard pressure chamber 107. . Therefore, the correction may be made so that the standby time WT becomes shorter as the viscosity of the hydraulic oil or its correlation value (for example, the cooling water temperature THW) increases. In this case, the standby time WT can be set more suitably in accordance with the leakage amount of the hydraulic oil.
[0096]
In general, the effect of the intake air temperature on the change of the cooling water temperature THW, in other words, the effect of the outside air temperature on the change of the cooling water temperature THW is compared with the effect of the intake air temperature on the viscosity of the hydraulic oil, in other words, the change of the temperature of the hydraulic oil. Then it is small. Therefore, for example, when the intake air temperature is low, a situation is assumed in which the cooling water temperature THW is high, but the temperature of the hydraulic oil is low. Therefore, when calculating the standby time WAT in the first embodiment or the standby time WT in the second embodiment, a value that takes into consideration not only the coolant temperature THW but also the intake air temperature is correlated with the viscosity of the hydraulic oil. It may be used as a value. In this case, the accuracy of the correlation with respect to the viscosity of the hydraulic oil is further increased, and the operation and effect of each of the above embodiments naturally become highly accurate. In this case as well, the cooling water temperature THW and the intake air temperature, which are the detection values of the water temperature sensor and the intake air temperature sensor generally provided in the internal combustion engine, are used instead of the viscosity of the hydraulic oil. Therefore, it is not necessary to separately provide a sensor for detecting the viscosity of the hydraulic oil.
[0097]
In the first and second embodiments, the coolant temperature THW is used as the correlation value indicating the viscosity of the hydraulic oil. However, an oil temperature sensor for detecting the temperature of the hydraulic oil is separately provided in the internal combustion engine, and the detection is performed. The value may be used as a correlation value representing the same viscosity.
[0098]
-Since the oil pump 121 also stops while the engine is stopped, the pressure drop in the unlocking pressure chambers 37 and 38 as described above also becomes remarkable. Therefore, in each of the above-described embodiments, the above-described advance standby processing is executed when the engine is started. On the other hand, even during operation of the engine, the pressure in the unlocking pressure chambers 37 and 38 decreases due to leakage of hydraulic oil from the retard pressure chamber 107 and the advance pressure chamber 106, and the lock mechanism is unlocked. Failure may occur. Therefore, the advance waiting process described in the first and third embodiments may be executed during engine operation. In this case, it is possible to suppress occurrence of insufficient lock release of the lock mechanism during operation of the engine.
[0099]
In the above embodiments, the lock mechanism is configured to restrict the relative rotation of the vane body 101 and the housing 103 at the most retarded position. However, the lock mechanism controls the relative rotation of the vane body 101 and the housing 103 at the most advanced position. The present invention is similarly applicable to a configuration including a restricting lock mechanism. In each of the above embodiments, the case where the camshaft 130 for driving the intake valve is provided with the variable valve timing mechanism is described. However, the same applies to the case where the camshaft for driving the exhaust valve is provided with the variable valve timing mechanism. The invention is applicable.
[0100]
In these cases, the same effect can be obtained by performing the valve timing control in a manner according to the above embodiments.
In each of the above embodiments, after the hydraulic oil is supplied to the retard pressure chamber 107, the hydraulic oil is supplied to the advance pressure chamber 106. In addition, hydraulic oil is supplied to both the pressure chambers so that the pressure in the retard pressure chamber 107 becomes higher than the pressure in the advance pressure chamber 106. Then, after the standby time WAT or the standby time WT has elapsed, or after the oil pressure P has become equal to or higher than the allowable pressure OKP, the pressure in the advance pressure chamber 106 becomes higher than the pressure in the retard pressure chamber 107. The hydraulic oil may be supplied to both pressure chambers.
[0101]
In the above embodiments, the case where the present invention is applied to the control device of the so-called vane type variable valve timing mechanism has been described. In addition, there is a rotating body such as a helical gear type variable valve timing mechanism that rotates relative to each other, and a mechanism that changes the valve timing of the engine valve by their operation, and a lock that regulates the operation of each rotating body. The present invention can be similarly applied to any control device for a variable valve timing mechanism having a mechanism.
[0102]
In addition, technical ideas that can be grasped from each of the above-described embodiments or modifications thereof will be described below along with their effects.
(A) In the valve timing control device for an internal combustion engine according to claim 1, the parameters for estimating the fluid pressure state in the pressure chamber include a viscosity of a working fluid or a correlation value thereof, and an engine stop time before starting the engine. A valve timing control device for an internal combustion engine.
[0103]
According to this device, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
(B) In the valve timing control device for an internal combustion engine according to the sixth aspect, the predetermined time is corrected to be shorter as the viscosity of the working fluid immediately after the engine is stopped or the correlation value thereof is higher. Timing control device for an internal combustion engine.
[0104]
According to the device, the time for supplying the working fluid to the pressure chamber on the side where the control position is maintained can be more suitably set in accordance with the leakage amount of the working fluid.
[0105]
(C) First and second rotating bodies capable of changing the valve timing of the internal combustion engine by relative rotation, and an operation for changing the rotation phase of the second rotating body with respect to the first rotating body. The first and second pressure chambers to which fluid is supplied, and the relative rotation of these rotators are regulated at a predetermined rotation phase corresponding to the valve timing maximum control position of the first and second rotators, and A lock mechanism for releasing the regulation based on a fluid pressure supplied to the first and second pressure chambers, and a pressure sensor for detecting a discharge pressure of a pump for supplying a working fluid to the first and second pressure chambers. A valve timing control device for an internal combustion engine, comprising: maintaining the valve timing maximum control position in the first and second pressure chambers when changing the phase from the predetermined rotation phase by the lock mechanism. The working fluid is supplied to one of the pressure chambers until a predetermined time variably set based on at least one of the viscosity of the working fluid or a correlation value thereof and the engine stop time before starting the engine elapses. At the same time, after supplying the working fluid to the one pressure chamber until the detection value of the pressure sensor becomes equal to or higher than the allowable pressure set based on the viscosity of the working fluid or its correlation value, the other pressure chamber A valve timing control device for an internal combustion engine, which supplies a working fluid to the engine.
[0106]
According to this device, it is possible to more reliably suppress the occurrence of insufficient release of the lock mechanism.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a structure of a variable valve timing mechanism according to a first embodiment of the invention.
FIG. 2 is a view showing a cross-sectional structure of a lock mechanism of the variable valve timing mechanism according to the embodiment.
FIG. 3 is a view showing a cross-sectional structure of a lock mechanism of the variable valve timing mechanism according to the embodiment.
FIG. 4 is an exemplary flowchart showing a procedure of an advance waiting process in the embodiment.
FIG. 5 is a view showing a map structure for calculating a standby time in the embodiment.
FIG. 6 is an exemplary flowchart showing a procedure of an advance waiting process in the second embodiment;
FIG. 7 is a diagram showing a map structure for calculating a standby time in the embodiment.
FIG. 8 is a schematic diagram illustrating a part of an oil circuit according to a third embodiment.
FIG. 9 is an exemplary flowchart showing the procedure of an advance waiting process in the embodiment.
FIG. 10 is a diagram showing a map structure for calculating an allowable oil pressure in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Water temperature sensor, 30 ... Housing hole, 30a ... Step part, 31 ... Lock pin, 31a ... Step part, 32 ... Lock hole, 33 ... Coil spring, 35 ... Advance-side oil passage, 36 ... Delay-side oil passage , 37, 38: pressure chamber for unlocking, 101: vane body, 102: vane, 103: housing, 104: recess, 105: cam pulley, 106: advance pressure chamber, 107: retard pressure chamber, 120: hydraulic control Valve: 121: oil pump; 122: electronic control unit; 130: cam shaft; 140: pressure sensor.

Claims (11)

First and second rotating bodies capable of changing the valve timing of the internal combustion engine by relative rotation, and a working fluid for changing the rotation phase of the second rotating body with respect to the first rotating body is supplied. The first and second pressure chambers and the predetermined rotation phase corresponding to the valve timing maximum control position of the first and second rotating bodies regulate the relative rotation of these rotating bodies, A valve timing control device for an internal combustion engine, comprising: a lock mechanism for releasing the regulation based on a fluid pressure supplied to the second pressure chamber.
When changing the phase from the predetermined rotation phase by the lock mechanism, one of the first and second pressure chambers that maintains the valve timing maximum control position is provided with a fluid pressure in the same pressure chamber. A valve timing control apparatus for an internal combustion engine, comprising: supplying a working fluid to a pressure chamber after supplying a working fluid until a predetermined time variably set based on a parameter for estimating a state elapses. The valve timing control device for an internal combustion engine according to claim 1, wherein the parameter for estimating the fluid pressure state in the pressure chamber is a viscosity of a working fluid or a correlation value thereof. 3. The valve timing control device for an internal combustion engine according to claim 2, wherein when the viscosity of the working fluid or its correlation value is equal to or more than a predetermined value, the predetermined time is set to increase as the viscosity increases. 4. The valve timing control of an internal combustion engine according to claim 2, wherein when the viscosity of the working fluid or its correlation value is equal to or less than a predetermined value, the predetermined time is set to increase as the viscosity decreases. apparatus. The valve timing control device for an internal combustion engine according to claim 1, wherein the parameter for estimating the fluid pressure state in the pressure chamber is an engine stop time before starting the engine. The valve timing control device for an internal combustion engine according to claim 5, wherein the predetermined time is set longer as the engine stop time becomes longer. First and second rotating bodies capable of changing the valve timing of the internal combustion engine by relative rotation, and a working fluid for changing the rotation phase of the second rotating body with respect to the first rotating body is supplied. The first and second pressure chambers and the rotation phases corresponding to the valve timing maximum control positions of the first and second rotating bodies are regulated, and the first and second pressure chambers are regulated in relative rotation. A lock mechanism for releasing the regulation based on the fluid pressure supplied to at least one of the pressure chambers and a pressure sensor for detecting a discharge pressure of a pump for supplying a working fluid to the first and second pressure chambers. In the valve timing control device for an internal combustion engine provided,
The valve timing maximum control position is maintained in the first and second pressure chambers until the detection value of the pressure sensor becomes equal to or higher than an allowable pressure set based on the viscosity of the working fluid or a correlation value thereof. A valve timing control device for an internal combustion engine, wherein a working fluid is supplied to one of the pressure chambers on the side of the internal combustion engine, and then the working fluid is supplied to the other pressure chamber. The valve timing control device for an internal combustion engine according to claim 7, wherein the allowable pressure is set higher as the viscosity of the working fluid or a correlation value thereof increases. The valve timing control device for an internal combustion engine according to any one of claims 2 to 4, 7, and 8, wherein the correlation value is a temperature of a working fluid. The valve timing control device for an internal combustion engine according to any one of claims 2 to 4, 7, and 8, wherein the correlation value is a cooling water temperature. The valve timing control device for an internal combustion engine according to any one of claims 2 to 4, 7, and 8, wherein the correlation values are a cooling water temperature and an intake air temperature.

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