JP2011236822A - Device and method for controlling hydraulic valve timing variable mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly prevent collision between components caused by a runaway of a hydraulic valve timing variable mechanism due to a cam torque variation.SOLUTION: An internal combustion engine mounts a lift amount/operating angle variable mechanism 7 in which a valve-lift amount and valve-operating angle of an intake valve are variable; and the hydraulic valve timing variable mechanism 5 which is driven by hydraulic pressure and in which a valve timing of the intake valve is variable. In the internal combustion engine, an electronic control unit 1 is designed so that both an advance guard value and a retard guard value within a control range of the hydraulic valve timing variable mechanism 5 is variable in response to the valve-operating angle.

Description

  The present invention relates to a control device and a control method for a hydraulic valve timing variable mechanism that is driven by hydraulic pressure to vary the valve timing of an engine valve, and more particularly to a valve lift that varies at least one of a lift amount and an operating angle of an engine valve. The present invention relates to an apparatus and method applied to an internal combustion engine equipped with a variable amount / valve operating angle variable mechanism.

  As a mechanism mounted on an internal combustion engine such as a vehicle, various valve characteristic variable mechanisms that make the valve characteristic of an intake valve variable have been proposed and put into practical use. As such a valve characteristic variable mechanism, a lift amount / working angle variable mechanism that makes the valve lift amount and valve working angle of the intake valve variable, a valve timing variable mechanism that makes the valve timing of the intake valve variable, and the like are known. .

  In an internal combustion engine equipped with both the lift amount / working angle variable mechanism and the valve timing variable mechanism, if the valve timing is advanced while the valve lift amount and valve working angle are expanded, the intake valve and the piston There is a risk of occurrence of a so-called valve stamp. Therefore, conventionally, in an internal combustion engine equipped with these two mechanisms, as shown in Patent Document 1, the upper limit value (advance guard value) of the target valve timing advance amount becomes smaller as the valve lift amount becomes larger. In addition, the control for avoiding the occurrence of the valve stamp as described above is performed by variably setting the advance angle guard value according to the valve lift amount.

JP 2007-285292 A

  By the way, as the valve timing variable mechanism, a hydraulic variable mechanism driven by hydraulic pressure is widely used. FIG. 5 shows a front sectional structure of an example of such a hydraulic valve timing variable mechanism. As shown in the figure, this hydraulic valve timing variable mechanism is configured to include two rotating bodies, a vane rotor 50 and a housing 51. Among these, the vane rotor 50 is fixed to the intake camshaft so as to be integrally rotatable. The housing 51 is fixed to a cam sprocket that is drivingly connected to the crankshaft via a timing chain so as to be integrally rotatable.

  On the outer periphery of the vane rotor 50 formed in a substantially cylindrical shape, a plurality of (three in the same figure) vanes 52 projecting in the radial direction from the outer periphery are formed. Further, the same number of recesses 53 as the vanes 52 are formed on the inner periphery of the housing 51 formed in a substantially annular shape. In each recess 53, one vane 52 is accommodated.

  Inside the recess 53, two oil chambers are defined by the vane 52 accommodated therein. Of these, the oil chamber formed in the camshaft counter-rotating direction of the vane 52 includes an advance oil chamber 54 into which hydraulic pressure for rotating the vane rotor 50 relative to the housing 51 in the camshaft rotating direction is introduced. It has become. The oil chamber formed in the camshaft rotating direction of the vane 52 is a retarded oil chamber 55 into which hydraulic pressure for rotating the vane rotor 50 relative to the housing 51 in the camshaft counter-rotating direction is introduced. Yes.

  Here, when the hydraulic pressure is applied to the advance oil chamber 54 and the hydraulic pressure is released from the retard oil chamber 55, the vane rotor 50 is urged by the oil pressure in the advance oil chamber 54 to rotate the camshaft relative to the housing 51. Relative rotation in the direction. Thus, when the vane rotor 50 is relatively rotated in the camshaft rotation direction, the rotation phase of the camshaft is advanced and the valve timing of the intake valve is advanced. On the other hand, when the hydraulic pressure is applied to the retarded oil chamber 55 and the hydraulic pressure is released from the advanced oil chamber 54, the vane rotor 50 is urged by the hydraulic pressure of the retarded oil chamber 55, and the camshaft counteracts against the housing 51. Relative rotation is achieved in the rotation direction. Thus, when the vane rotor 50 is relatively rotated in the camshaft counter-rotating direction, the rotational phase of the camshaft is delayed and the valve timing of the intake valve is retarded.

  By the way, the camshaft for opening and closing the intake / exhaust valve is constantly subjected to torque fluctuations due to the spring force of the valve spring and the inertia of the valve itself. Such cam torque fluctuations may cause the cam angle phase to be poorly maintained, that is, the so-called hydraulic valve timing variable mechanism may be violated. Such a ramping of the hydraulic valve timing variable mechanism becomes particularly noticeable when the oil temperature increases and the viscosity thereof decreases. When the fluctuation of the hydraulic valve timing variable mechanism becomes large, the vane 52 may greatly shake with respect to the housing 51 as shown in FIG. 6, and the vane 52 may collide with the circumferential side wall 53 </ b> A of the recess 53.

  As in the above-described prior art, merely setting the target valve timing advance guard value variably according to the valve lift amount does not limit the valve timing when it is positioned near the most retarded angle. The collision of the vane 52 in the vicinity of the retard position does not have any deterrent effect in preventing it.

Such a problem is not limited to the configuration illustrated in FIG. 5, and is generally common to hydraulic valve timing variable mechanisms driven by hydraulic pressure.
The present invention has been made in view of such circumstances, and a problem to be solved is to suitably suppress a collision between component parts caused by a fluctuation of a hydraulic valve timing variable mechanism due to cam torque fluctuation. Another object of the present invention is to provide a control device and control method for a hydraulic valve timing variable mechanism that can be used.

  The invention according to claim 1 is applied to an internal combustion engine equipped with a variable lift amount / working angle mechanism that makes at least one of a valve lift amount and a valve working angle of an engine valve variable, and is driven by hydraulic pressure and is The premise is a control device for a hydraulic valve timing variable mechanism that varies the valve timing of the engine valve. In order to solve the above problem, the invention according to claim 1 is directed to advance angle guard value and retard angle guard value of the control range of the hydraulic valve timing variable mechanism according to at least one of the valve lift amount and the valve working angle. Guard value variable means for making both of them variable is provided.

  Guards are set on both the advance side and the retard side of the control range of the hydraulic valve timing variable mechanism, and the mechanism is placed in the vicinity of the most advanced position and the most retarded position of the operation range where the collision of the constituent members occurs If this is not achieved, it is possible to prevent a collision between the constituent members due to a mechanism malfunction caused by cam torque fluctuations. However, if the guard range is widened to provide a margin, the control range of the hydraulic valve timing variable mechanism is narrowed.

  On the other hand, the magnitude of cam torque fluctuation in an internal combustion engine equipped with a variable lift / working angle mechanism varies depending on the setting of the valve lift and valve working angle. Therefore, if the guard range is set according to at least one of the valve lift amount and the valve operating angle, the guard range can be set according to the magnitude of cam torque fluctuation at that time.

  Therefore, according to the first aspect of the present invention, it is possible to suitably suppress the collision between the components due to the fluctuation of the hydraulic valve timing variable mechanism due to the cam torque fluctuation while suppressing the reduction of the control range. It becomes like this.

  Incidentally, the cam torque fluctuation usually increases as the valve lift amount and the valve operating angle increase. Therefore, according to claim 2, as at least one of the valve lift amount and the valve operating angle increases, the advance guard value is changed to a more retarded value and the retard guard value is changed to a more advanced value. If the guard value varying means is configured as described above, it is possible to accurately prevent a collision between components.

  Incidentally, such a control device for a hydraulic valve timing variable mechanism according to the present invention is a vane that is driven and connected to either one of a camshaft and an engine output shaft and projects radially from the outer periphery thereof. A vane rotor formed with the camshaft and the other of the camshaft and the engine output shaft is driven and connected to the vane rotor so as to be rotatable relative to the vane rotor, and a recess for accommodating the vane is formed on the inner periphery thereof. And the relative rotation of the vane rotor and the housing based on the adjustment of the hydraulic pressure in the oil chamber on the advance side and the retard side respectively formed on both sides of the vane in the circumferential direction by dividing the recess with the vane. Therefore, application to a hydraulic valve timing variable mechanism configured to make the valve timing of the engine valve variable is preferable. It has become a thing.

  The invention according to claim 4 as a control method of the hydraulic valve timing variable mechanism is an internal combustion engine equipped with a variable lift amount / operating angle mechanism that makes at least one of a valve lift amount and a valve operating angle of an engine valve variable. And a hydraulic valve timing variable mechanism that is driven by hydraulic pressure to vary the valve timing of the engine valve, the advance guard value of the control range of the hydraulic valve timing variable mechanism, and The retard guard value is set, and both the advance guard value and the retard guard value are made variable according to at least one of the valve lift amount and the valve operating angle.

  According to the above method, both the advance guard value and the retard guard value in the control range of the hydraulic valve timing variable mechanism are made variable in accordance with at least one of the valve lift amount and the valve operating angle. Therefore, if the hydraulic valve timing variable mechanism is controlled in this manner, the collision between the components due to the fluctuation of the hydraulic valve timing variable mechanism due to cam torque fluctuation is suitably suppressed while suppressing the reduction of the control range. Will be able to.

  According to claim 5, as at least one of the valve lift amount and the valve operating angle increases, the advance guard value becomes a more retarded value and the retard guard value becomes a more advanced value. If changed, it becomes possible to prevent the collision between the components of the hydraulic valve timing variable mechanism accurately.

1 is a schematic view schematically showing a control structure of a variable valve system of an internal combustion engine to which a control device for a hydraulic valve timing variable mechanism according to an embodiment of the present invention is applied. The graph which shows the relationship between a valve working angle, cam torque, and cam angle phase fluctuation width. The flowchart which shows the process sequence of VVT advance / retard guard value setting routine employ | adopted as the said embodiment. The graph which shows the relationship between the valve working angle and the advance / retard guard value in the same embodiment. Sectional drawing which shows the front sectional structure of an example of a hydraulic valve timing variable mechanism. The figure which expands and shows the vane of the hydraulic valve timing variable mechanism, and its peripheral part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying the present invention will be described in detail with reference to FIGS. The control device for the hydraulic valve timing variable mechanism of the present embodiment is applied to an internal combustion engine equipped with a lift amount / working angle variable mechanism that makes the valve lift amount and valve working angle of the intake valve variable. Yes.

  FIG. 1 shows a control structure of a variable valve system of an internal combustion engine to which the present embodiment is applied. The variable valve system of the internal combustion engine includes a lift / working angle variable mechanism 7 that makes the valve lift amount and valve working angle of the intake valve variable, and a hydraulic pressure that is driven by oil pressure and makes the valve timing of the intake valve variable. A variable valve timing mechanism (VVT) 5 is provided. The variable hydraulic valve timing mechanism 5 employed in the present embodiment has the same configuration as that illustrated in FIG.

  Such control of the variable valve system is executed by the electronic control unit 1. The electronic control unit 1 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output port (I / O). Here, the CPU executes various arithmetic processes related to the control of the variable valve system, and the ROM stores a control program and data. The RAM temporarily stores the calculation results of the CPU, the detection results of the sensors, and the like, and the I / O functions as an interface that mediates exchange of signals with the outside.

  Detection signals from the crank angle sensor 2, the cam angle sensor 3, the working angle sensor 4, and the like are input to the input port of the electronic control unit 1. Here, the crank angle sensor 2 is a sensor that detects the rotation angle of the crankshaft that is the engine output shaft, and the cam angle sensor 3 determines the rotation angle of the intake camshaft that opens and closes the intake valve according to the rotation. It is a sensor to detect. The working angle sensor 4 is a sensor that detects the valve working angle of the intake valve that is variable by the lift amount / working angle variable mechanism 7.

  The electronic control unit 1 drives the hydraulic valve timing variable mechanism 5 by instructing a hydraulic control valve 6 that adjusts the hydraulic pressure applied to each oil chamber (see FIG. 5) of the hydraulic valve timing variable mechanism 5. To control the valve timing of the intake valve. Further, the electronic control unit 1 controls the valve lift amount and valve working angle of the intake valve by instructing the actuator 8 to drive the lift / working angle variable mechanism 7.

  By the way, on the intake camshaft of the internal combustion engine, the torque of the valve spring constantly occurs due to the spring force of the valve spring and the inertia of the valve itself. Due to such cam torque fluctuations, cam angle retention failure causes the so-called hydraulic valve timing variable mechanism 5 to be out of order. Such a ramp may cause a collision between the components of the hydraulic valve timing variable mechanism 5.

  Such a collision between the components due to the rampage occurs when the hydraulic valve timing variable mechanism 5 is positioned in the vicinity of the most advanced position or the most retarded position of the operation range. Therefore, in order to avoid a collision between components due to the rampage, the control range of the hydraulic valve timing variable mechanism 5 is limited by setting guards on both the advance side and the retard side, so that the hydraulic valve timing can be reduced. It is only necessary that the variable mechanism 5 does not reach the vicinity of the most advanced position or the most retarded position.

  On the other hand, as shown in FIG. 2, the fluctuation amplitude of the cam torque increases as the valve lift amount and valve operating angle of the intake valve increase. Then, the fluctuation width of the hydraulic valve timing variable mechanism 5 also increases as the cam torque fluctuation amplitude increases. Therefore, if the guard range is set according to the valve lift amount and the valve operating angle, it is possible to set the guard range without excess or deficiency according to the magnitude of cam torque fluctuation at that time. Therefore, in the present embodiment, during the operation angle variable control, the advance angle guard value and the retard angle guard value of the control range of the hydraulic valve timing variable mechanism 5 are variably set according to the valve operation angle at that time. Like to do.

  FIG. 3 shows a flowchart of the VVT advance / retard guard value setting routine employed in this embodiment. The processing of this routine is repeatedly executed by the electronic control unit 1 at regular control cycles during operation of the internal combustion engine.

  When this routine is started, first, in step S100, it is confirmed whether or not the intake valve operating angle variable control is being performed. If the operating angle variable control is not being executed (S100: NO), the processing of this routine is terminated as it is. On the other hand, if the working angle variable control is being performed (S100: YES), the process proceeds to step S101, and in step S101, the control range of the hydraulic valve timing variable mechanism 5 according to the current valve working angle of the intake valve. The advance angle guard value and the retard angle guard value are set.

  FIG. 4 shows how the advance guard value and the retard guard value are set. As shown in the figure, as the valve operating angle increases, the advance guard value is changed to a more retarded value, and the retard guard value is changed to a more advanced value.

In this embodiment, the electronic control unit 1 corresponds to the guard value varying means.
According to the control device and control method of the hydraulic valve timing variable mechanism of the present embodiment described above, the following effects can be obtained.

  (1) In the present embodiment, the electronic control unit 1 makes both the advance guard value and the retard guard value of the control range of the hydraulic valve timing variable mechanism 5 variable according to the valve operating angle. ing. Guards are set on both the advance side and the retard side of the control range of the hydraulic valve timing variable mechanism 5, and the mechanism reaches the most advanced position and the most retarded position in the operation range where the collision of the constituent members occurs. If this is not done, it is possible to prevent a collision between the constituent members due to a mechanism malfunction caused by cam torque fluctuations. However, if the guard range is widened to provide a margin, the control range of the hydraulic valve timing variable mechanism 5 is narrowed. On the other hand, the magnitude of cam torque fluctuation in an internal combustion engine equipped with the lift amount / working angle variable mechanism 7 varies depending on the setting of the valve lift amount and the valve working angle. Therefore, if the guard range is set according to at least one of the valve lift amount and the valve operating angle, the guard range can be set according to the magnitude of cam torque fluctuation at that time. Therefore, according to the present embodiment, it is possible to suitably suppress the collision between the components due to the fluctuation of the hydraulic valve timing variable mechanism due to the cam torque fluctuation while suppressing the reduction of the control range. .

  (2) In this embodiment, the advance guard value is changed to a more retarded value and the retard guard value is changed to a more advanced value as at least one of the valve operating angles increases. An electronic control unit 1 is configured. The cam torque fluctuation increases as the valve lift amount and the valve operating angle increase. Therefore, it becomes possible to prevent the collision between the component parts accurately.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the advance guard value and the retard guard value are variably set according to the valve working angle of the intake valve. However, the lift is performed so that the valve lift amount is changed simultaneously with the valve working angle. When the amount / working angle variable mechanism 7 is configured, the advance guard value and the retard guard value can be variably set according to the valve lift amount.

  In the above embodiment, the application example to the internal combustion engine in which the hydraulic valve timing variable mechanism 5 and the lift / working angle variable mechanism 7 are provided on the intake side has been described. However, in the present invention, these mechanisms are provided on the exhaust side. The present invention can be similarly applied to the provided internal combustion engine.

  In the above embodiment, the variable lift amount / operating angle mechanism 7 is configured so that the valve lift amount is changed at the same time as the valve operating angle. However, the present invention is applicable to either the valve operating angle or the valve lift amount. The present invention can also be applied to an internal combustion engine equipped with a variable mechanism that changes only one of them, in the same manner as in the above-described embodiment, or in an aspect similar thereto.

  The control device and control method of the present invention is not limited to the configuration illustrated in FIG. 5 as long as it is a mechanism that is driven by hydraulic pressure and makes the valve timing of the engine valve variable. Can be applied to the mechanism.

  DESCRIPTION OF SYMBOLS 1 ... Electronic control unit (guard value variable setting means), 2 ... Crank angle sensor, 3 ... Cam angle sensor, 4 ... Working angle sensor, 5 ... Hydraulic valve timing variable mechanism, 6 ... Hydraulic control valve, 7 ... Lift amount / Working angle variable mechanism, 8 ... actuator, 50 ... vane rotor, 51 ... housing, 52 ... vane, 53 ... recess (53A ... circumferential side wall), 54 ... advance side oil chamber, 55 ... retard side oil chamber.

Claims (5)

The engine valve is applied to an internal combustion engine equipped with a variable lift amount / working angle mechanism that varies at least one of a valve lift amount and a valve working angle of the engine valve, and is driven by hydraulic pressure to vary the valve timing of the engine valve. In the control device of the hydraulic valve timing variable mechanism,
Guard value varying means for varying both the advance guard value and the retard guard value of the control range of the hydraulic valve timing varying mechanism according to at least one of the valve lift amount and the valve working angle. Control device for hydraulic valve timing variable mechanism. The guard value varying means sets the advance guard value to a more retarded value and the retard guard value to a more advanced value as at least one of the valve lift amount and the valve operating angle increases. The control device for a hydraulic valve timing variable mechanism according to claim 1, wherein each of the control devices is changed. The hydraulic valve timing variable mechanism is:
A vane rotor that is connected to one of the camshaft and the engine output shaft and has vanes that protrude radially from the outer periphery thereof;
A housing that is drivingly connected to the other of the camshaft and the engine output shaft, is coaxially rotatable with the vane rotor, is relatively rotatable, and has a recess formed in an inner periphery thereof. With
By partitioning the concave portion with the vane, the vane rotor and the housing are relatively rotated based on the hydraulic pressure adjustment in the advance side and retard side oil chambers respectively formed on both sides in the circumferential direction of the vane. The control device for a hydraulic valve timing variable mechanism according to claim 1, wherein the valve timing of the engine valve is made variable. The engine valve is applied to an internal combustion engine equipped with a variable lift amount / working angle mechanism that varies at least one of a valve lift amount and a valve working angle of the engine valve, and is driven by hydraulic pressure to vary the valve timing of the engine valve. A method of controlling a hydraulic valve timing variable mechanism,
The advance angle guard value and the retard angle guard value of the control range of the hydraulic valve timing variable mechanism are set, and both the advance angle guard value and the retard angle guard value are set to at least one of the valve lift amount and the valve working angle. A control method of a hydraulic valve timing variable mechanism, characterized in that it is variable according to The advance guard value is changed to a more retarded value and the retard guard value is changed to a more advanced value as at least one of the valve lift amount and the valve operating angle increases. The control method of the hydraulic valve timing variable mechanism according to claim 4.

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