JP2010025127A - Variable valve gear for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an intake valve and an exhaust valve from interfering with a piston in the vicinity of a top dead center, in a valve train variably controlling both the valve timing (opening/closing timing) and valve lift of the intake valve and exhaust valve. <P>SOLUTION: In a control device for a variable valve train, the target valve timing of a variable valve timing mechanism VTC on the side of the intake valve is determined based on the engine load and engine speed (S2); meanwhile, the target valve timing upper limit of the VTC is set according to the actual valve lift of a variable valve lift mechanism VEL on the side of the intake valve. When the target valve timing of the VTC determined based on the engine load and engine speed exceeds the target valve timing upper limit (S5), the target valve timing is restricted to the target valve timing upper limit of the VTC (S7). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that performs valve timing control and valve lift amount control independently on at least one of an intake valve and an exhaust valve.

Conventionally, various variable valve operating devices that control the valve timing or valve lift amount of an intake valve or an exhaust valve to an optimal control amount in accordance with the operating state of the engine have been put into practical use.
In order to further improve the engine output and the exhaust gas purification performance, an apparatus for variably controlling both the valve timing and the valve lift amount of the intake valve or the exhaust valve has been developed.
In Patent Document 1, a valve timing (opening / closing timing) variable mechanism of an intake valve and a valve characteristic switching mechanism are arranged on an intake side camshaft so as to vary both the valve timing and the valve lift amount of the intake valve. Therefore, the valve timing and the valve lift amount of the intake valve are variably controlled for each operation region determined by the engine speed and load.
JP 2000-328971 A

  By the way, in the conventional variable valve mechanism of the internal combustion engine, the valve timing control of the intake valve and the valve lift amount control are performed independently, and each control range depends on the engine performance (operating performance) according to each control characteristic. And exhaust gas purification performance, etc.). However, when these controls are used together, for example, as shown in FIG. 10, in the partial load rotation region, the valve timing is controlled to the advance side and the valve lift amount is controlled to the high lift amount side. The valve lift in the vicinity of the top dead center of the piston becomes extremely large, and there is a possibility that interference occurs between the intake valve and the piston.

  In order to limit the maximum advance value of the intake valve timing variable mechanism and the valve lift of the valve characteristics switching mechanism so that the valve lift does not become excessively large near the top dead center of the piston, it is mechanically limited by a stopper or the like. In this case, the control range is narrowed, and the upper limit of the control amount is limited even in the valve timing and valve lift amount control areas where no interference occurs between the intake valve and the piston. The effect of increasing the output and improving the exhaust purification performance by using the variable control and the variable valve lift amount control together cannot be obtained sufficiently.

Even if the valve timing variable control and the valve lift amount variable control are used in combination, if the valve timing of the exhaust valve is controlled to the retard side and the valve lift amount is controlled to a high lift amount, the vicinity of the top dead center of the piston Therefore, there is a possibility that interference occurs between the exhaust valve and the piston, which causes the same problem.
The present invention has been made paying attention to such a conventional problem, and is a variable valve operating device for an internal combustion engine that uses both valve timing control of intake and exhaust valves and valve lift amount control and performs independently. The purpose of the present invention is to expand the control range of the valve timing and the valve lift amount as much as possible while preventing the interference between the intake / exhaust valve and the piston, thereby enabling the engine performance to be maximized.

For this reason, as described in claim 1, the first invention is
A control device for a variable valve mechanism that performs valve lift control so as to continuously change a valve lift amount with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operation state of valve timing that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of a valve lift amount of the corresponding intake valve or exhaust valve is set according to the operation state of the valve timing. A valve lift amount limit value setting unit for setting a limit value for limiting;
A valve lift control limiting unit that limits a control range of the valve lift control based on a limit value set by the valve lift amount limit value setting unit;
It is comprised from these.

According to the first aspect of the invention, when the valve lift amount is controlled as required according to the operating state of the engine regardless of the valve timing operation state in which the intake valve or the exhaust valve is variably controlled, it interferes with the piston. In such a case, it is possible to prevent interference with the piston by limiting the control range of the control of the valve lift amount.
Even if the valve lift amount is controlled as required regardless of the valve timing operation state, if it does not interfere with the piston, the other is controlled as it is as required to maximize the engine performance. be able to. For example, it is possible to improve the output and the exhaust purification performance in the operating state such as during cold start or lean combustion.

Moreover, as described in claim 7, the second invention is as follows.
A control device for a variable valve mechanism that performs valve timing control so as to change valve timing with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operation state of a valve lift amount that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of a valve timing of a corresponding intake valve or exhaust valve according to the operation state of the valve lift amount A valve timing limit value setting unit for setting a limit value for limiting
A valve timing control limiting unit that limits a control range of the valve timing control based on a limit value set by the valve timing limit value setting unit;
It is comprised from these.

According to the second aspect of the present invention, when the valve timing is controlled as required according to the operating state of the engine regardless of the operating state of the valve lift amount that is variably controlled of the intake valve or the exhaust valve, it interferes with the piston. In such a case, interference with the piston can be prevented by limiting the control range of the valve timing control.
Further, even if the valve timing is controlled as required regardless of the operation state of the valve lift amount, if it does not interfere with the piston, the other is controlled as it is as it is, as in the first invention, The engine performance can be maximized.

Moreover, as described in claim 13, the third invention provides
A control device for a variable valve mechanism that performs valve lift control so as to continuously change a valve lift amount with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
The operation state of the valve timing that is variably controlled with respect to at least one of the intake valve and the exhaust valve is input, and the control range of the valve lift amount of the corresponding intake valve or exhaust valve is limited according to the operation state of the valve timing. A valve lift amount limit value setting unit for setting a limit value for
Based on the limit value set by the valve lift amount limit value setting unit, when the valve timing of the intake valve is in the range from the intermediate advance position to the most advanced position, or the valve timing of the exhaust valve is intermediate A valve lift control limiting unit for limiting the control range of the valve lift control when the valve is in the range from the advanced position to the most retarded position;
It is comprised from these.

According to the third aspect of the invention, since the valve timing operation state of the intake valve or the exhaust valve is in a range where there is a possibility of interference with the piston by the valve lift control, the limit value is used for restriction. Limiting processing is performed only when the calculation load can be reduced.
Moreover, as described in claim 18, the fourth invention is as follows.
A control device for a variable valve mechanism that performs valve timing control so as to change valve timing with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operating state of a valve lift amount that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of the valve timing of the corresponding intake valve or exhaust valve is set according to the operating state of the valve lift amount. A valve lift amount limit value setting unit for setting a limit value for limiting;
Based on the limit value set by the valve timing limit value setting unit, the valve lift amount of the intake valve or exhaust valve increases from a medium lift amount to the possibility that the intake valve or exhaust valve and the piston may interfere with each other. A valve timing control limiting unit that limits a control range of the valve timing control when the amount is in a range;
It is comprised from these.
According to the fourth aspect of the invention, the limit value is limited only when the operating state of the valve lift amount of the intake valve or the exhaust valve is in a range where the valve timing control may interfere with the piston. Limiting processing is performed only when necessary, and the calculation load can be reduced.

Moreover, as described in claim 27, the fifth invention provides:
A valve lift amount target value setting unit for setting a target value according to the engine operating state in order to continuously change the valve lift amount for at least one of the intake valve or the exhaust valve of the internal combustion engine;
A variable valve mechanism control device comprising: a valve lift control unit that controls a valve lift amount based on an actual valve lift operation state and a target value;
In the valve timing control unit that controls the valve timing of at least one of the intake valve or the exhaust valve, in order to limit the control range of the valve timing control of the corresponding intake valve or exhaust valve according to the valve lift operating state, A valve lift operation state signal output unit for outputting a valve lift amount operation state signal to the valve timing control unit is included.

  According to the fifth aspect of the present invention, from the control device of the variable valve mechanism that variably controls the valve lift amount of the intake valve or the exhaust valve, the valve timing control unit that variably controls the valve timing of the intake valve or the exhaust valve is controlled. By outputting the lift amount operation state signal, the valve timing control unit limits the control range of the valve timing control of the corresponding intake valve or exhaust valve according to the input valve lift operation state, and interferes with the piston. Can be prevented.

Moreover, as described in claim 28, the sixth invention provides:
A valve timing target value setting unit that sets a target value according to the engine operating state in order to change the valve timing for at least one of the intake valve and the exhaust valve of the internal combustion engine;
A variable valve mechanism control device comprising: a valve timing control unit that controls valve timing based on an actual valve timing operating state and a target value;
In the valve lift control unit that controls the valve lift amount of at least one of the intake valve or the exhaust valve, in order to limit the control range of the valve lift control of the corresponding intake valve or exhaust valve according to the valve timing operation state, A valve timing operation state signal output unit for outputting a valve timing operation state signal to the valve lift control unit is included.

  According to the sixth aspect of the invention, from the control device of the variable valve mechanism that variably controls the valve timing of the intake valve or the exhaust valve, the valve lift control unit that variably controls the valve lift amount of the intake valve or the exhaust valve is controlled. By outputting the lift amount operation state signal, the valve lift control unit restricts the control range of the valve lift control of the corresponding intake valve or exhaust valve according to the input valve timing operation state, and interferes with the piston. Can be prevented.

The system block diagram of embodiment of this invention. The principal part perspective view of the variable valve lift amount control means used for embodiment of this invention. FIG. 3 is an A arrow view of FIG. 2. A is an operation explanatory view showing a valve opening state at the minimum lift amount of the variable valve lift amount control means. B is an operation explanatory view showing a closed valve state at the time of the minimum lift. A is an operation explanatory view showing a valve opening state when the variable valve lift amount control means is at a high lift amount. B is an operation explanatory view showing a closed valve state at the time of maximum lift. The flowchart concerning Example 1 of this invention. The flowchart concerning Example 2 of this invention. The flowchart of the front | former stage concerning Example 3 of this invention. The flowchart of the latter part concerning Example 3 of this invention. The time chart which showed the open characteristic of the valve in a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a system configuration of an internal combustion engine including a variable valve operating apparatus according to an embodiment of the present invention.
An air flow meter 3 for detecting an intake air amount Q is provided in the intake passage 2 of the internal combustion engine 1, and a throttle valve 4 for controlling the intake air amount Q is provided on the downstream side thereof.

Further, a fuel injection valve 6 for injecting fuel into the combustion chamber 5 of each cylinder downstream of the intake passage 2 is provided. The fuel injected from the fuel injection valve 5 and the throttle valve 4 through the intake valve 7 are provided. The air-fuel mixture with the sucked air is compressed by the piston 8 in the combustion chamber 5 and ignited by spark ignition by the spark plug 9 provided in the combustion chamber 5.
Exhaust gas from the internal combustion engine 1 is discharged from the combustion chamber 5 to the exhaust passage 11 via the exhaust valve 10, and discharged to the atmosphere via the exhaust purification catalyst 12 provided downstream of the exhaust passage 11.

The intake valve 7 and the exhaust valve 10 are driven to open and close by operation of cams provided on the intake side camshaft 14 and the exhaust side camshaft 15, respectively, with the crankshaft 13 as a power source.
On the intake side, a variable valve lift amount control device (hereinafter referred to as “VEL”) 16 composed of a multi-node link-like mechanism for continuously and variably controlling the valve lift amount and the operating angle of the intake valve 7 is provided on the intake side. Provided on the outer periphery of the cam shaft 14. Further, the VEL 16 is provided with a VEL operating angle sensor 17 that detects the valve lift amount and the operating angle of the intake valve 7. The detailed structure of the VEL 16 will be described later.

  Similarly, the intake side is configured by a mechanism that continuously and variably controls the rotational phase difference between the crank timing 13 and the intake camshaft 14 to advance or retard the valve timing (valve opening / closing timing) of the intake valve 7. A variable valve timing mechanism (hereinafter referred to as VTC) 18 is provided at one end of the intake camshaft 14. An intake side cam angle sensor 19 for detecting the rotational position of the intake side camshaft 14 is provided at the other end of the intake side camshaft 14.

  An engine control unit (ECU) 20 is provided with an output signal from the air flow meter 3 and an engine load and an engine rotation based on a crank angle signal output from a crank angle sensor 21 provided on the crankshaft 13 to detect a rotational position. The speed is obtained, and the fuel injection amount, the VEL target valve lift amount, and the VTC target valve timing are calculated. Further, based on the VEL operating angle signal output from the VEL operating angle sensor 17, a feedback control signal is given to the VEL so that the actual VEL valve lift amount converges to the target VEL valve lift amount. Similarly, the actual VTC valve timing is obtained from the phase difference between the output signal from the intake cam angle sensor 19 and the crank angle signal output from the crank angle sensor 21, and this actual VTC valve timing converges to the target VTC angle. Thus, a feedback control signal is given to the VTC 18.

Next, the VEL 16 will be described with reference to FIGS.
The control shaft 23 of the VEL 16 is arranged in parallel with the intake side cam shaft 14 and both ends thereof are pivotally supported by bearings 24 fixed to a cylinder block (not shown).
The control cam 25 has a substantially cylindrical shape having an outer diameter larger than that of the control shaft 23, and is arranged in a state where the shaft center is eccentric by a predetermined amount α on the control shaft 23.

The rocker arm 26 has a substantially rhombus shape, and the outer periphery of the control cam 25 is slidably inserted into a hole penetrating in the center.
The link rod 27 has a substantially crescent shape, and one end of the link rod 27 is rotatably connected to one end of the rocker arm 26 via a pin 28 and the other end is eccentric from the axis of the intake side camshaft 14. Are connected to each other via a pin 29 so as to freely rotate.

The drive cam 30 includes a cylindrical cam body 30a having a large outer diameter and a cylindrical portion 30b having a small outer diameter provided adjacent to one end of the cam main body 30a. A shaft hole 30c is formed through the center of the portion 30b, and the intake camshaft 14 is slidably inserted into the shaft hole 30c.
The axial center of the cylindrical portion 30b coincides with the axial center X of the intake camshaft 14, but the axial center Y of the cam body 30a is a predetermined amount from the axial center X of the intake camshaft 14. Eccentric.

The link arm 31 has an annular shape with a larger outer periphery than the drive cam 30, and the outer periphery of the cam body 30 a of the drive cam 30 is freely slidable via a bearing 32 in a hole formed through the center portion. Inserted into.
The end of the link arm 31 protruding in the outer diameter direction is connected to the other end of the rocker arm 26 via a pin 33 so as to freely rotate.

The intake cam 34 has a raindrop shape, and the intake camshaft 14 is fitted and fixed in a shaft hole 34b penetrating the base end portion 34a. On the other hand, the intake cam 34 protrudes in the outer diameter direction from the base end portion. A pin hole 34d is formed through the cam nose portion 34c located in the pin hole 34d. The pin 29 is fitted into the pin hole 34d and is rotatably connected to the link rod 27.
The valve lifter 35 has a cylindrical shape with a lid, and the cam surface 34e of the intake cam 34 abuts on a predetermined position according to the swing position on the upper surface, while the intake valve 7 is fixed on the lower portion.

In the electric actuator 36, a worm gear 37 fixed to the end of the drive shaft meshes with a gear fixed to one end of the control shaft 23, and the control shaft 23 is rotated within a certain range by a drive signal output from the ECU 20. Let
A VEL operating angle sensor 17 is provided at one end of the control shaft 23, detects the valve lift amount of the VEL 16 from the rotation amount of the control shaft 23, and outputs a detection signal to the ECU 20.

Next, the operating principle of the VEL 16 will be described.
FIGS. 4A and 4B show the VEL valve state when the minimum lift amount control is performed. In response to the drive signal from the ECU 20, the control shaft 23 is controlled to minimize the lift amount. When the surrounding rotation is applied, the thick portion 25a of the control cam 25 moves upward, and the rocker arm 26 also moves upward in synchronization therewith. At this time, the cam nose portion 34 c of the intake cam 34 is lifted upward via the link rod 27. Therefore, the cam surface 34e of the intake cam 34 that contacts the valve lifter 35 by the rotation of the intake side camshaft 14 is in the vicinity of the base end portion 34a, and the valve lift amount is controlled to a small lift amount indicated by L1 in the drawing.

  On the other hand, FIGS. 5A and 5B show the open state of the VEL when performing the minimum lift amount control. Upon receiving a drive signal from the ECU 20, the control shaft 23 is set to maximize the lift amount. When a counterclockwise rotation is applied, the thick portion 25a of the control cam 25 moves downward, and in synchronization with this, the rocker arm 26 also moves downward. At this time, the cam nose portion 34 c of the intake cam 34 is pushed downward via the link rod 27. Therefore, the cam surface 34e of the intake cam 34 that contacts the valve lifter 35 due to the rotation of the intake side camshaft 14 is between the tip end of the cam nose portion 34c and the base end portion 34a, and the valve lift amount is a large lift indicated by L1 in the figure. Controlled by quantity.

Next, control of VEL and VTC in the first embodiment of the present invention will be described.
Regarding the control of the valve lift amount by VEL, a target valve lift amount is set based on the engine rotational speed Ne and the fuel injection amount Tp, and a proportional component, an integral component, and a differential component are set so as to be the target valve lift amount. The used control (refer to the second embodiment described later) is executed without limiting the control range.

On the other hand, the valve timing control by the VTC is controlled while limiting the control range so that the intake valve 7 does not interfere with the piston according to the control state of the valve lift amount by the VEL. The control operation of the VTC will be described based on the flowchart of FIG.
In step 1 (hereinafter abbreviated as S1), based on the intake air amount Q detected from the air flow meter 3 and the engine rotational speed Ne detected from the crank angle sensor 13, the fuel injection amount Tp (= K · Q / Ne: K is a constant).

In S2, the target valve timing VTCTRG0 of the VTC 18 is calculated from a previously stored table based on the fuel injection amount Tp calculated in S1 and the engine speed Ne.
In S <b> 3, the actual VEL valve lift amount VCS_IN of the VEL 16 is obtained from the detection signal of the VEL operating angle sensor 17.

In S4, based on the detected actual VEL valve lift amount VCS_IN, the VTC target valve timing upper limit value VTCLIM is calculated from a previously stored table.
The VTC target valve timing upper limit value VTCLIM is an interference between the intake valve 7 and the piston 8 even if the VTC 18 is controlled to the most advanced angle value in a region where the valve lift amount of the intake valve 7 is from a low lift amount to an intermediate lift amount. Therefore, the VTC target valve timing upper limit value VTCLIM is set to be the same as the most advanced angle position regulated by the stopper mechanism of the VTC 18.

On the other hand, when the valve lift amount of the intake valve 7 is in the region of a high lift amount, the VTC 18 approaches the most advanced angle position, so that the intake valve 7 and the piston 8 may interfere with each other at the piston top dead center. In the region where the amount of lift is high, the VTC target valve timing upper limit value VTCLIM is gradually set to the retard side.
In S5, the VTC target valve timing VTCTRG0 obtained from S2 is compared with the VTC target valve timing upper limit value VTCLIM obtained from S4. When the VTC target valve timing VTCTRG0 is equal to or less than the VTC target valve timing upper limit value VTCLIM, the process proceeds to S6, and when the VTC target valve timing VTCTRG0 exceeds the VTC target valve timing upper limit value VTCLIM, the process proceeds to S7.

In S6, the VTC target valve timing VTCTRG0 referenced from the table in S2 is determined as the final VTC target valve timing VTCTRG.
On the other hand, in S7, the VTC target valve timing upper limit value VTCLIM obtained from S4 is determined as the final VTC target valve timing VTCTRG instead of the VTC target valve timing VTCTRG0 referred to in the table of S2.

In S8, the actual VTC valve timing VTCNOW is obtained based on the detection signals of the crank angle sensor 21 and the intake cam angle sensor 19.
In S9, a deviation VTCERR between the VTC target valve timing VTCTRG determined in S6 and S7 and the actual VTC valve timing VTCNOW is calculated.
In S10, based on the deviation VTCERR determined in S9 and the feedback gain Gp (proportional component), Gi (integral component), and Gd (differential component), the proportional component control amount VTCP and integral component control are expressed by the following equations. An amount VTCi and a differential control amount VTCd are obtained respectively.

VTCp = Gp · VTCERR
VTCi = VTCiz + Gi · VTCERR
VTCd = Gd · (VTCERR−VTCERRz)
Here, VTCiz: the previous value of the integral control amount VTCi VTCERRz: the previous value of the deviation VTCERR In S11, the VTC duty value VTCDTY is calculated from the value obtained by adding the basic duty value BASDTYvtc and the control amounts VTCp, VTCi, and VTCd. Is used as an output signal to drive the actuator of the VTC 18, and the series of flows is completed.

Next, control of VEL and VTC in the second embodiment of the present invention will be described.
For valve timing control by VTC, a target valve timing is set based on the engine speed Ne and the fuel injection amount Tp, and control using a proportional component, an integral component, and a differential component so as to be the target valve timing ( The first embodiment) is executed without limiting the control range.

On the other hand, the control of the valve lift amount by VEL is performed while limiting the control range so that the intake valve 7 does not interfere with the piston according to the control state of the valve timing by the VTC. The control operation of the VEL will be described based on the flowchart of FIG.
In S21, the fuel injection amount Tp is calculated based on the intake air amount Q and the engine rotational speed Ne in the same manner as in S1.

In S22, the target valve lift amount VELTRG0 of VEL16 is obtained from a table stored in advance based on the fuel injection amount Tp and the engine rotational speed Ne, similar to the calculation of the VTC target valve timing of VTC18 in S2.
In S23, the actual VTC valve timing VTCNOW is obtained from the phase difference between the output signal of the crank angle sensor 21 and the output signal of the intake cam angle sensor 19.

  In S24, the VEL target valve lift amount upper limit value VELLIM is calculated based on the VTC valve timing VTCNOW obtained in S23. As in the case of the first embodiment, when the actual VTC valve timing is controlled to the advance side and the valve lift amount is controlled to the high lift amount side, between the intake valve 7 and the piston 8 at the piston top dead center. In this embodiment, in the range where the actual VTC valve timing is from the intermediate advance amount to the most advanced angle amount, the target valve lift amount is reduced to the lower valve lift as it is displaced to the advance side. It is designed to limit gradually to the side.

  In S25, the target valve lift amount VELTRG0 obtained in S22 is compared with the VEL valve lift amount upper limit value VELLIM obtained in S24. When the VEL target valve lift amount VELTRG is less than or equal to the VEL valve lift amount upper limit value VELLIM, the process proceeds to S26, and when the VEL target valve lift amount VELTRG0 exceeds the VEL target valve lift amount upper limit value VTCLIM, the process proceeds to S27.

In S26, the VEL target valve lift amount VELTRG0 referenced from the table in S22 is determined as the final VEL target valve lift amount VELTRG.
On the other hand, in S27, instead of the VEL target valve lift amount VELTRG0 referred to in the table of S22, the VEL target valve lift amount upper limit value VELLIM obtained from S24 is determined as the final VEL target valve lift amount VELTRG.

In S28, the actual VEL valve lift amount VCS_IN is obtained based on the detection signal of the VEL angle sensor 17.
In S29, a deviation VELERR between the VEL target valve lift amount VELTRG determined in S26 and S27 and the actual valve lift amount VCS_IN is calculated.
In S30, based on the deviation VELERR determined in S29 and the feedback gains Gp ′ (proportional component), Gi ′ (integral component), Gd ′ (differential component), the proportional control amount VELP, An integral component control amount VELi and a derivative component control amount VELd are obtained respectively.

VELp = Gp '· VELERR
VELi = VEliz + Gi ′ · VELERR
VELd = Gd ′ · (VELERR−VELERRz)
Here, VEliz: the previous value of the integral control amount VELi VEERRz: the previous value of the deviation VEERR In S31, the VEL duty value VELDTY is calculated from the value obtained by adding the basic duty value BASDTYve1 and the control amounts VElp, VELi, VELd VELDTY value VELDTY And the electric motor 45 of the VEL 16 is driven using this as an output signal, and a series of flows is completed.
Then, using this as an output signal, the electric motor 45 of the VEL 16 is driven, and a series of flows is completed.

  Therefore, according to the first and second embodiments, the control amount of either the valve lift amount or the valve timing is limited in the region where VEL is the high lift amount and VTC is the most advanced angle. As a result, the interference between the intake valve 7 and the piston 8 at the top dead center of the piston is suppressed, and in other regions, the maximum advance angle amount of the mechanically locked VTC or the high lift amount of the VEL is obtained. By ensuring the operating range, it is possible to improve output or exhaust purification performance under all operating conditions.

  In these embodiments, only the control amount of the valve lift amount or the valve timing is limited. However, the control range of the valve lift amount is limited according to the control state of the valve timing, and the valve lift amount is controlled. It can also be set as the structure which restrict | limits the control range of valve timing according to a control state. Hereinafter, a description will be given of a third embodiment in which both the control ranges are limited as described above.

8 and 9 show a flowchart of the control of the third embodiment.
In S41, the fuel injection amount Tp is set in the same manner as described above, and in S42 and S43, the VTC target valve timing VTCTRG0 and the VEL target valve lift amount VELTRG0 are similarly set based on the engine rotational speed Ne and the fuel injection amount Tp, respectively. calculate.
In S44, based on the VTC target valve timing VTCTRG0 and the VEL target valve lift amount VELTRG0, the target value correction coefficient KTRG is referred from a map as shown in the figure.

In S45, the VTC target valve timing VTCTRG0 and the VEL target valve lift amount VELTRG0 are corrected by values multiplied by the target value correction coefficient KTRG (<1), respectively, to obtain the VTC target valve timing VTCTRG1 and the VEL target valve lift amount VELTRG1. .
Here, the target value correction coefficient KTRG is a region where the intake valve and the piston interfere when the actual valve timing and the valve lift amount are controlled to the VTC target valve timing VTCTRG0 and the VEL target valve lift amount VELTRG0. As described above, each value is set to a value that can prevent interference between the intake valve and the piston by changing the value to a value corrected by a value multiplied by the target value correction coefficient KTRG (<1). In the region where the intake valve and the piston do not interfere with each other with the VTC target valve timing VTCTRG0 and the VEL target valve lift amount VELTRG0, the target value correction coefficient KTRG = 1 is set and correction is not performed. Further, the target value correction coefficient KTRG may be set separately for VTC target valve timing VTCTRG0 correction and for VEL target valve lift amount VELTRG0 correction. In some areas, VTC target valve timing VTCTRG0 and VEL target Only one of the valve lift amounts VELTRG0 may be set to be corrected.

In S46, the actual VTC valve timing VTCNOW and the actual VEL valve lift amount VCS_IN are read.
In S47 and S48, the VTC target valve timing upper limit value VTCLIM and the VEL target valve lift amount upper limit value VELLIM are calculated in the same manner as in S4 and S24.
In S49, the VTC target valve timing VTCTRG1 corrected in S45 is compared with the VTC target valve timing upper limit value VTCLIM calculated in S47, and the more retarded side (the smaller advance amount side) is set. Is set to the final VTC target valve timing VTCTRG.

In S50, the VEL target valve lift amount VELTRG1 corrected in S45 is compared with the VEL target valve lift amount upper limit value VELLIM calculated in S48, and the one set to the lower lift amount side is selected and finally VEL target valve lift amount VELTRG is set.
That is, due to a control delay or the like, the actual VTC valve timing VTCNOW is set to the advanced side with respect to the corrected VTC target valve timing VTCTRG1, or the actual VEL valve lift amount VCS_IN is set to the VEL target valve lift amount VELTRG1. If it is set on the high lift side, the intake valve 7 and the piston may interfere with each other, which is prevented.

In S51, the VTC duty value VTCDTY is calculated as in S10 and S11, an output signal is output, and the actuator of the VTC 18 is driven.
In S52, the VEL duty value VELDTY is calculated in the same manner as in S30 and S31, an output signal is output, the electric motor 45 of the VEL 16 is driven, and the series of flows is completed.

In the third embodiment, although the control is complicated, the respective limit amounts of the valve timing and the valve lift amount can be reduced, so that the control suitable for the operation state request can be performed as much as possible.
In the above description, the case where the VTC and VEL are provided only on the intake valve side is shown. However, in the case where the VTC and VEL are provided on the exhaust valve side, the retard amount of the valve timing of the exhaust valve is large. The present invention can also be applied to the case where the exhaust valve may interfere with the piston when the valve lift amount is set on the high lift amount side. In the above embodiment, the advance amount of the valve timing of the intake valve is set. This can be implemented in the same manner by replacing it with the retard amount of the valve timing of the exhaust valve.

For example, in the above-described embodiment, the electric actuator 36 is used as the driving means for the VEL, but a driving device using a hydraulic actuator may be used instead of the electric actuator. Further, the VTC may be an electric VTC instead of a hydraulic one like the VEL.
Further, as the variable means of the valve lift amount, VEL that continuously variably controls the valve lift amount and the operating angle is used as the valve lift amount variable means. However, the valve lift amount may be variably controlled in several stages. Good.

DESCRIPTION OF SYMBOLS 3 ... Air flow meter 7 ... Intake valve 8 ... Piston 13 ... Crankshaft 14 ... Intake side cam shaft 15 ... Exhaust side cam shaft 16 ... VEL 17 ... VEL operation angle sensor 18 ... VTC 19 ... Intake side cam angle sensor 20 ... Control unit (ECU) 21 ... Crank angle sensor 23 ... Control shaft 25 ... Control cam 26 ... Rocker arm 27 ... Link rod 30 ... Drive cam 31 ... Ring arm 34 ... Intake cam 35 ... Valve lifter 36 ... Electric actuator

Claims (28)

A control device for a variable valve mechanism that performs valve lift control so as to continuously change a valve lift amount with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operation state of valve timing that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of a valve lift amount of the corresponding intake valve or exhaust valve is set according to the operation state of the valve timing. A valve lift amount limit value setting unit for setting a limit value for limiting;
A valve lift control limiting unit that limits a control range of the valve lift control based on a limit value set by the valve lift amount limit value setting unit;
A variable valve mechanism control device comprising:   2. The valve lift amount limit value setting unit sets the limit value of the valve lift amount of the intake valve to a lower lift amount side as the valve timing of the intake valve is controlled to the advance side. The control apparatus of the variable valve mechanism described in 1.   The valve lift amount limit value setting unit sets the limit value of the valve lift amount of the exhaust valve to a low lift amount side as the valve timing of the exhaust valve is controlled to the retard side. The control apparatus of the variable valve mechanism described in 1. A valve lift amount target value setting unit that sets a target value of the valve lift amount according to the engine operating state is provided.
The valve lift control limiting unit compares the limit value set by the valve lift amount limit value setting unit with the target value set by the valve lift amount target value setting unit, and finally determines according to the comparison result. The control device for the variable valve mechanism according to any one of claims 1 to 3, wherein a control range of the valve lift control is limited by a target value set in (1).   The valve lift control limiting unit resets the final target value of the valve lift amount to the limit value when the target value set by the valve lift amount target value setting unit is larger than the limit value. Accordingly, the control range of the valve lift control is limited, and the control device for the variable valve mechanism according to claim 4. The valve lift amount limit value setting unit sets, as the limit value, a correction coefficient for limiting the valve lift amount based on at least the input valve timing operating state.
5. The valve lift control limiting unit limits a control range of valve lift control by correcting a target value of the valve lift amount with the correction coefficient to obtain a final target value. The control apparatus of the variable valve mechanism described in 1. A control device for a variable valve mechanism that performs valve timing control so as to change valve timing with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operation state of a valve lift amount that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of a valve timing of a corresponding intake valve or exhaust valve according to the operation state of the valve lift amount A valve timing limit value setting unit for setting a limit value for limiting
A valve timing control limiting unit that limits a control range of the valve timing control based on a limit value set by the valve timing limit value setting unit;
A variable valve mechanism control device comprising:   The variable valve mechanism according to claim 7, wherein the valve timing limit value setting unit sets the valve timing limit value of the intake valve to a retard side as the valve lift amount of the intake valve increases. Control device.   9. The allowable value according to claim 7, wherein the valve timing limit value setting unit sets the limit value of the valve timing of the exhaust valve to an advance side as the valve lift amount of the exhaust valve increases. Control device for variable valve mechanism. A valve timing target value setting unit that sets a valve timing target value according to the engine operating state is provided.
The valve timing control limiting unit compares the limit value set by the valve timing limit value setting unit with the target value set by the valve timing target value setting unit, and finally sets according to the comparison result The control device for the variable valve mechanism according to any one of claims 7 to 9, wherein a control range of the valve timing control is limited by the set target value.   The valve timing control limiting unit is configured to set the valve timing of the intake valve when the target value of the valve timing of the intake valve set by the valve timing target value setting unit exceeds the limit value and is set to the advance side. 11. The control device for a variable valve mechanism according to claim 10, wherein the control range of the valve timing control is limited by resetting the final target value to the limit value.   The valve timing control limiting unit is configured to set the valve timing of the exhaust valve when the target value of the valve timing of the exhaust valve set by the valve timing target value setting unit exceeds the limit value and is set to the retard side. The control apparatus for a variable valve mechanism according to claim 10 or 11, wherein a control range of valve timing control is limited by resetting the final target value of the control value to the limit value. A control device for a variable valve mechanism that performs valve lift control so as to continuously change a valve lift amount with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
The operation state of the valve timing that is variably controlled with respect to at least one of the intake valve and the exhaust valve is input, and the control range of the valve lift amount of the corresponding intake valve or exhaust valve is limited according to the operation state of the valve timing. A valve lift amount limit value setting unit for setting a limit value for
Based on the limit value set by the valve lift amount limit value setting unit, when the valve timing of the intake valve is in the range from the intermediate advance position to the most advanced position, or the valve timing of the exhaust valve is intermediate A valve lift control limiting unit for limiting the control range of the valve lift control when the valve is in the range from the advanced position to the most retarded position;
A variable valve mechanism control device comprising: The valve lift amount limit value setting unit sets the limit value as a value that limits the target value of the valve lift amount set according to the engine operating state,
14. The control of the variable valve mechanism according to claim 13, wherein the valve lift control limiting unit controls the valve lift amount based on a target value of the valve lift amount set by being limited by the limit value. apparatus.   When the valve timing of the intake valve is in the range from the intermediate advance position to the most advanced position, the valve lift amount limit value setting unit sets the intake valve so that the valve timing of the intake valve is controlled to the advance side. The control device for a variable valve mechanism according to claim 13 or 14, wherein the limit value of the valve lift amount is set to the low lift amount side.   When the valve timing of the exhaust valve is in the range from the intermediate advance position to the most retarded position, the valve lift amount limit value setting unit is configured to control the exhaust valve so that the valve timing of the exhaust valve is controlled to the retard side. The control device for a variable valve mechanism according to any one of claims 13 to 15, wherein a limit value of the valve lift amount is set to a low lift amount side.   The valve lift amount limiting unit sets the target value to a limit value when the target value of the valve lift amount of the intake valve or the exhaust valve set according to the engine operating state is set to a value larger than the limit value. The control apparatus for a variable valve mechanism according to any one of claims 14 to 16, wherein the control range of the valve lift control is limited by resetting to the above. A control device for a variable valve mechanism that performs valve timing control so as to change valve timing with respect to at least one of an intake valve and an exhaust valve of an internal combustion engine,
An operating state of a valve lift amount that is variably controlled with respect to at least one of the intake valve or the exhaust valve is input, and a control range of the valve timing of the corresponding intake valve or exhaust valve is set according to the operating state of the valve lift amount. A valve lift amount limit value setting unit for setting a limit value for limiting;
Based on the limit value set by the valve timing limit value setting unit, the valve lift amount of the intake valve or exhaust valve may increase from the middle lift amount to the possibility that the intake valve or exhaust valve and the piston interfere with each other. A valve timing control limiting unit that limits the control range of the valve timing control when
A variable valve mechanism control device comprising: The valve timing limit value setting unit sets the limit value as a value that limits the target value of the valve timing set according to the engine operating state,
19. The control device for a variable valve mechanism according to claim 18, wherein the valve timing control limiting unit controls the valve timing based on a target value of the valve timing set by limiting by the limit value.   19. The variable valve operating system according to claim 18, wherein the valve timing limit value setting unit sets the limit value as a value that limits the most advanced position of the intake valve or the most retarded position of the exhaust valve. Control device for the mechanism.   When the valve lift amount of the intake valve is not in the range of a medium lift amount to a high lift amount that may cause interference between the intake valve and the piston, the valve timing limit value setting unit sets the valve timing of the intake valve. The control device for a variable valve mechanism according to any one of claims 18 to 20, wherein the limit value is set to a most advanced position.   The valve timing limit value setting unit sets the valve timing of the exhaust valve when the valve lift amount of the exhaust valve is not within a range of a medium lift amount to a high lift amount that may cause interference between the exhaust valve and the piston. The control device for a variable valve mechanism according to any one of claims 18 to 21, wherein the limit value is set to a most retarded angle position.   The valve timing limit value setting unit has a large valve lift amount of the intake valve when the valve lift amount of the intake valve is in a range of a medium lift amount to a high lift amount that may cause interference between the intake valve and the piston. The control device for a variable valve mechanism according to any one of claims 18 to 22, wherein the limit value of the valve timing of the intake valve is set to the retarded side as occasion demands.   The valve timing limit value setting unit has a large valve lift amount of the exhaust valve when the valve lift amount of the exhaust valve is in a range from a medium lift amount to a high lift amount that may cause interference between the exhaust valve and the piston. 24. The control device for a variable valve mechanism according to any one of claims 18 to 23, wherein the limit value of the valve timing of the exhaust valve is set to the advance side.   The valve timing limiter resets the target value to the limit value when the target value of the valve timing of the intake valve set according to the engine operating state is set to the advance side of the limit value. The control range of valve timing control is limited by the control device of the variable valve mechanism according to any one of claims 19 and 21 to 24.   The valve timing limiting unit resets the target value to the limit value when the target value of the valve timing of the exhaust valve set according to the engine operating state is set to the retard side than the limit value. 26. The control device for a variable valve mechanism according to any one of claims 19 and 21 to 25, wherein the control range of the valve timing control is limited by: A valve lift amount target value setting unit for setting a target value according to the engine operating state in order to continuously change the valve lift amount for at least one of the intake valve and the exhaust valve of the internal combustion engine;
A control device for a variable valve mechanism, comprising: a valve lift control unit that controls a valve lift amount based on an actual valve lift operation state and a target value;
In the valve timing control unit that controls the valve timing of at least one of the intake valve and the exhaust valve, in order to limit the control range of the valve timing control of the corresponding intake valve or exhaust valve according to the valve lift operation state, A control apparatus for a variable valve mechanism, comprising: a valve lift operation state signal output unit for outputting a valve lift operation state signal to the valve timing control unit. A valve timing target value setting unit that sets a target value according to the engine operating state in order to change the valve timing for at least one of the intake valve and the exhaust valve of the internal combustion engine;
A variable valve mechanism control device comprising: a valve timing control unit that controls valve timing based on an actual valve timing operating state and a target value;
In the valve lift control unit that controls the valve lift amount of at least one of the intake valve or the exhaust valve, in order to limit the control range of the valve lift control of the corresponding intake valve or exhaust valve according to the valve timing operation state, A control device for a variable valve mechanism including a valve timing operation state signal output unit for outputting a valve timing operation state signal to the valve lift control unit.

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