JP4399387B2 - Control device for variable valve mechanism - Google Patents

Description

  The present invention relates to a control device for a variable valve mechanism that makes variable the center phase of the operating angle of an intake valve of an internal combustion engine and the lift characteristics (lift amount and / or operating angle) of the intake valve.

In Patent Document 1, in an electromagnetically driven valve that drives an engine valve with an electromagnetic coil, the output values at the fully open position and the fully closed position of a lift sensor that detects the lift amount of the engine valve are learned when the starter motor is energized. An apparatus is disclosed.
Further, in Patent Document 2, in the variable valve timing mechanism that changes the valve timing of the engine valve by adjusting the phase difference of the camshaft with respect to the crankshaft, the most retarded position of the valve timing is learned for each engine operating region. An apparatus is disclosed.
JP-A-11-210510 JP 11-82073 A

  By the way, according to the techniques disclosed in Patent Documents 1 and 2, it is possible to accurately detect the control position in the variable range by learning the fully closed / open position of the engine valve and the most retarded position of the valve timing. However, the variation in the variable range cannot be absorbed. For example, in a V-type engine, when the intake valve of each bank is provided with a variable valve mechanism, there is a deviation in the air amount between the banks. As a result, the stability of engine rotation and the quietness of the engine are reduced.

  Therefore, it is desirable to learn the variation in the air amount and to correct the variable valve mechanism of each bank. However, there is a variable lift mechanism that makes the lift characteristics (lift amount and / or operating angle) of the engine valve variable. When a variable valve mechanism that combines a variable valve timing mechanism that adjusts the phase difference of the camshaft with respect to the crankshaft is provided, the air amount changes depending on both the lift characteristics and the center phase of the operating angle. Therefore, there has been a problem that appropriate correction control cannot be applied to the variable lift mechanism and the variable valve timing mechanism.

  The present invention has been made in view of the above problems, and in an engine provided with a variable valve mechanism that makes the center phase of the operating angle of the intake valve of the internal combustion engine and the lift characteristic of the intake valve variable, the operating angle It is an object of the present invention to provide a control device that can perform correction control separately for variations in the center phase and variations in lift characteristics.

Therefore, the invention according to claim 1 is a control device for a variable valve mechanism that makes variable the center phase of the operating angle of the intake valve of the internal combustion engine and the lift characteristics of the intake valve, and depends on the center phase of the intake valve. The amount of air flow and the amount of air that depends on the lift characteristics of the intake valve are individually learned by dividing the operating region based on the state quantity of the intake system, and the amount of air depends on the center phase. After the learning is completed, the variation in the air amount depending on the lift characteristics is learned .
By configuring as above, the state quantity of the intake system, and the operating area to be large variations influence the opening area of the intake valve, and a large receiving operating range variation effects of the center phase of the operating angle of the intake valve (valve closing timing) It discriminate | determines and learns the air quantity dispersion | variation separately in each operation area | region. In addition, since it is divided into an operation region in which the air amount changes depending on the center phase and an operation region in which the air amount changes depending on the center phase and lift characteristics, the air region depends exclusively on the center phase. The variation in the lift characteristics is learned after the variation learning in the operation region where the amount changes ends and the influence of the center phase is eliminated.

Accordingly, it becomes possible to perform correction control separately for the variation in the center phase of the operating angle and the variation in the lift characteristics, and for example, in a V-type engine, it is possible to accurately correct the air amount variation between banks, The stability and quietness of engine rotation can be improved.
According to a second aspect of the present invention, an operation region in which variation in the amount of air depending on the lift characteristics is learned is set in an operation region in which the gas flow velocity passing through the intake valve is sonic velocity, and the gas flow velocity is non-sonic velocity. to become operating region, and configured to set an operating region for learning the variation of the air amount which depends on the center phase.

According to such a configuration, it is possible to separately learn the variation in the air amount depending on the center phase and the variation in the air amount depending on the lift characteristics based on the gas flow rate.

Therefore, it is possible to learn with high accuracy by separating the variation in the center phase of the operating angle and the variation in lift characteristics.
According to a third aspect of the present invention, a non-learning region is set between an operation region in which variation in air amount depending on the center phase is learned and an operation region in which variation in air amount depending on the lift characteristic is learned. The configuration.

According to such a configuration, in the operation region where the characteristics become unstable between the operation region where the air amount changes depending on the center phase and the operation region where the air amount changes depending on the center phase and the lift characteristic. By performing learning, erroneous learning is prevented.

  Accordingly, it is possible to accurately learn the variation in the air amount depending on the variation in the center phase of the operating angle and the variation in the air amount depending on the variation in the lift characteristics.

Embodiments of the present invention will be described below.
FIG. 1 is a system configuration diagram of an internal combustion engine for a vehicle according to an embodiment.
In FIG. 1, an internal combustion engine 101 is a V-type engine composed of two banks on the left and right. However, the internal combustion engine 101 may be a horizontally opposed engine.
An electronic control throttle 104 is interposed in the intake pipe 102 of the engine 101, and the air that has passed through the electronic control throttle 104 is distributed to each bank and each cylinder.

In each cylinder, air is sucked into the combustion chamber 106 via the intake valve 105.
The combustion exhaust gas is discharged from the combustion chamber 106 via the exhaust valve 107, and then exhaust gas is collected for each bank and purified by the front catalyst 108a, 108b and the rear catalyst 109a, 109b provided for each bank.
The exhausts of the banks after being purified by the rear catalysts 109a and 109b merge and flow into the muffler 103, and are then released into the atmosphere.

The exhaust valve 107 is opened and closed by a cam pivotally supported on the exhaust side camshaft 110 while maintaining a constant valve lift, valve operating angle, and valve timing.
On the other hand, on the intake valve 105 side, variable lift mechanisms 112a and 112b that continuously and variably control the valve lift amount together with the valve operating angle are provided for each bank.
Further, on the intake valve 105 side, variable valve timing mechanisms 113a and 113b for continuously and variably controlling the center phase of the valve operating angle of the intake valve 105 by changing the rotation phase of the intake side camshaft with respect to the crankshaft. It is provided for each bank.

A variable valve mechanism for the intake valve 105 is configured by a combination of the variable lift mechanisms 112a and 112b and the variable valve timing mechanisms 113a and 113b.
An electronic control unit (ECU) 114 incorporating a microcomputer has the electronic control throttle 104, variable lift mechanisms 112a and 112b, and variable valve timing mechanisms 113a and 113b so that a target intake air amount corresponding to the accelerator opening is obtained. To control.

  The ECU 114 includes an air flow meter 115 that detects the intake air flow rate of the engine 101, an accelerator sensor 116 that detects the amount of depression of the accelerator pedal, a crank angle sensor 117 that detects the rotation angle of the crankshaft, and an opening TVO of the throttle valve 103b. Detection signals from a throttle sensor 118 for detecting the water temperature, a water temperature sensor 119 for detecting the cooling water temperature of the engine 101, oxygen sensors 111a and 111b for detecting the exhaust air-fuel ratio of each bank, and the like are input.

A fuel injection valve 131 is provided at the intake port portion upstream of the intake valve 105 of each cylinder.
When the fuel in the fuel tank 132 is pumped to the fuel injection valve 131 by a fuel pump 133, and the fuel injection valve 131 is driven to open by an injection pulse signal (air-fuel ratio control signal) from the ECU 114, An amount of fuel proportional to the injection pulse width (valve opening time) is injected.

Next, the structure of the variable lift mechanisms 112a and 112b and the variable valve timing mechanisms 113a and 113b will be described with reference to FIGS.
In the V-type engine 101 of the embodiment, a pair of intake valves 105, 105 are provided in each cylinder, and an intake drive shaft 3 (intake side cam) that is rotationally driven by a crankshaft above the intake valves 105, 105. Is supported so as to be rotatable along the cylinder row direction.

A swing cam 4 that contacts the valve lifter 2a of the intake valve 105 and opens and closes the intake valve 105 is fitted on the intake drive shaft 3 so as to be relatively rotatable.
Between the intake drive shaft 3 and the swing cam 4, variable lift mechanisms 112a and 112b for continuously changing the operating angle and valve lift amount of the intake valve 105 are provided.
A variable valve timing mechanism 113a that continuously changes the center phase of the operating angle of the intake valve 105 by changing the rotational phase of the intake drive shaft 3 with respect to the crankshaft at one end of the intake drive shaft 3. 113b are arranged.

  As shown in FIGS. 2 and 3, the variable lift mechanisms 112 a and 112 b are externally fitted to a circular drive cam 11 that is eccentrically fixed to the intake drive shaft 3 and fixed to the drive cam 11. A ring-shaped link 12, a control shaft 13 that extends substantially parallel to the intake drive shaft 3 in the cylinder row direction, a circular control cam 14 that is fixedly provided eccentrically to the control shaft 13, and a relative to the control cam 14 A rocker arm 15 that is rotatably fitted and has one end connected to the tip of the ring-shaped link 12, and a rod-shaped link 16 connected to the other end of the rocker arm 15 and the swing cam 4. Yes.

The control shaft 13 is rotationally driven within a predetermined control range via a gear train 18 by an electric actuator 17 (motor).
With the above configuration, when the intake drive shaft 3 rotates in conjunction with the crankshaft, the ring-shaped link 12 moves substantially in translation through the drive cam 11 and the rocker arm 15 swings around the axis of the control cam 14. Then, the swing cam 4 swings via the rod-shaped link 16 and the intake valve 105 is driven to open and close.

Further, by changing the rotation angle of the control shaft 13, the axial center position of the control cam 14 serving as the rocking center of the rocker arm 15 is changed, and the posture of the rocking cam 4 is changed.
As a result, the operating angle of the intake valve 105 and the valve lift amount continuously increase or decrease while the central phase of the operating angle of the intake valve 105 remains substantially constant.
FIG. 4 shows the variable valve timing mechanisms 113a and 113b.

  The variable valve timing mechanisms 113a and 113b are fixed to a sprocket 25 that rotates in synchronization with the crankshaft, and a first rotating body 21 that rotates integrally with the sprocket 25 and one end of the intake drive shaft 3 by a bolt 22a. And a second rotating body 22 that rotates integrally with the intake drive shaft 3, and a cylindrical shape that meshes with the inner peripheral surface of the first rotating body 21 and the outer peripheral surface of the second rotating body 22 by a helical spline 26. Intermediate gear 23.

A drum 27 is connected to the intermediate gear 23 via a triple screw 28, and a torsion spring 29 is interposed between the drum 27 and the intermediate gear 23.
The intermediate gear 23 is urged in the retarding direction (leftward in FIG. 4) by a torsion spring 29. When a voltage is applied to the electromagnetic retarder 24 to generate a magnetic force, the intermediate gear 23 passes through the drum 27 and the triple thread screw 28. To move in the advance direction (right direction in FIG. 4).

The relative phase of the rotating bodies 21 and 22 changes according to the axial position of the intermediate gear 23, the phase of the intake drive shaft 3 with respect to the crankshaft changes, and the central phase of the operating angle of the intake valve 105 is continuous. To change.
The electric actuator 17 and the electromagnetic retarder 24 are driven and controlled by a control signal from the ECU 114.

In the present embodiment, the ECU 114 has a function of learning variation in the air amount between banks due to variation in the variable valve mechanism of the intake valve 105 that combines the variable lift mechanisms 112a and 112b and the variable valve timing mechanisms 113a and 113b. .
Hereinafter, details of the variation learning will be described.
The flowchart of FIG. 5 shows a first embodiment of means for detecting a torque step between banks, and calculates a torque step based on a detection signal from a crank angle sensor 117.

First, in step S1, a reference crank angle position for each stroke phase difference (180 deg CA for four cylinders and 120 deg CA for six cylinders) between cylinders is detected based on a detection signal from a crank angle sensor 117, and the reference crank angle position is detected. The period TINT is measured.
In step S2, a parameter MISC indicating a torque step between cylinders whose stroke is shifted by one revolution is calculated based on the cycle TINT.

In the calculation of the parameter MISC, the period TINT from the latest value TINT1 to the data TINTn a predetermined number of times before is stored in time series. That is, n of TINTn is a positive integer. If it is 2, it indicates the previous value, and if it is 3, it indicates the previous value.
Then, every time the cycle TINT is updated, the following calculation is performed.
“4-cylinder”

"For 6 cylinders"

In the above equation, TP is the basic fuel injection amount (basic injection pulse width) corresponding to the cylinder air amount, MISB2 is the previous value of the parameter MISB, and MISB3 is the previous value of the parameter MISB.
In step S3, the parameter MISC is divided into a right bank component and a left bank component.

Further, in step S4, average values MISCRAVE and MISCLAVE of the parameter MISC are obtained for each bank.
In step S5, the inter-bank torque step BNKSTPMS is obtained as a deviation between the average values MISCRAVE and MISCLAVE.
BNKSTPMS = MISCRAVE-MISCLAVE
The flowchart of FIG. 6 shows a second embodiment in which a torque step between banks is obtained as an air amount step.

In the second embodiment, a right bank air flow meter 115 and a left bank air flow meter 115 that individually measure the intake air flow rate for each bank are provided.
In step S11, the intake air flow rate QR in the right bank is detected based on the detection signal of the air flow meter 115 provided in the right bank.
In step S12, the intake air flow rate QL in the left bank is detected based on the detection signal of the air flow meter 115 provided in the left bank.

In step S13, a basic fuel injection amount (basic injection pulse width) TP0R corresponding to the cylinder air amount in the right bank is calculated.
TP0R = K × QR / N
K is a constant and N is the engine speed.
In step S14, a basic fuel injection amount (basic injection pulse width) TP0L corresponding to the cylinder air amount in the left bank is calculated.

TP0L = K × QL / N
In step S15, the basic fuel injection amount TP0R in the right bank is smoothed, and the result is set as TPR.
In step S16, the basic fuel injection amount TP0L in the left bank is smoothed, and the result is set as TPL.

In step S17, the right bank charging efficiency ITACR is calculated using the basic fuel injection amount TPMAX # when fully opened.
ITACR = TPR / TPMAX #
In step S18, the charging efficiency ITACL of the left bank is calculated using the basic fuel injection amount TPMAX # when fully opened.

ITACL = TPL / TPMAX #
In step S19, the filling efficiency ITACR of the right bank and the filling efficiency ITACL of the left bank are smoothed, and the results are set as ITACRAVE and ITACLAVE.
In step S20, a bank-to-bank filling efficiency step BNKSTPIC is calculated as a deviation between the right bank average filling efficiency ITACRAVE and the left bank average filling efficiency ITACLAVE.

BNKSTPIC = ITACRAVE-ITACLAVE
The flowchart of FIG. 7 shows a third embodiment in which the torque step between banks is determined as an air-fuel ratio step.
In step S31, the detection signal of the oxygen sensor 111a in the right bank is read.
In step S32, the detection signal of the oxygen sensor 111b in the left bank is read.

In step S33, a fuel injection amount feedback correction coefficient ALPHA for making the right bank air-fuel ratio coincide with the target air-fuel ratio is calculated based on the detection signal of the right bank oxygen sensor 111a.
In step S34, a fuel injection amount feedback correction coefficient ALPHAL for making the left bank air-fuel ratio coincide with the target air-fuel ratio is calculated based on the detection signal of the oxygen sensor 111b in the left bank.

In step S35, the air-fuel ratio feedback correction coefficient ALPHAR in the right bank is smoothed, and the result is set to AVEALPR.
In step S36, the left bank air-fuel ratio feedback correction coefficient ALPHAL is smoothed, and the result is set to AVEALPL.
In step S37, an inter-bank air-fuel ratio step BNKSTPAL is calculated as a deviation between the average correction coefficient AVEALPR for the right bank and the average correction coefficient AVEALPL for the left bank.

BNKSTPAL = AVEALPR-AVEALPL
The flowchart in FIG. 8 shows control for correcting the torque step between banks based on the torque step BNKSTPMS obtained in the flowchart in FIG.
In step S41, it is determined whether or not a value (ValveAA / Ne / Vol) obtained by dividing the opening area ValveAA of the intake valve 105 by the engine speed Ne and the exhaust amount Vol is equal to or greater than a first threshold value LRNAACET #.

The opening area ValveAA can be estimated from the operation amounts of the variable lift mechanisms 112a and 112b.
A region where ValveAA / Ne / Vol which is a state quantity correlated with the valve opening area is equal to or larger than the first threshold value LRNAACET # is shown in FIG. This is a region (B) where the gas amount does not change significantly, and is a region where the central phase (valve closing timing) of the operating angle of the intake valve 105 greatly affects the passing gas amount.

If ValveAA / Ne / Vol is greater than or equal to the first threshold value LRNAACET #, the process proceeds to step S42, and it is determined whether or not the torque step BNKSTPMS is smaller than the threshold value STPMR # (<0).
When the torque step BNKSTPMS is smaller than the threshold value STPMR #, this means that the MISC average value of the left bank is larger than the MISC average value of the right bank, in other words, the center phase in the right bank is greater than that of the left bank. The angle is retarded, indicating that the amount of air is increasing on the right bank side.

Therefore, when the torque step BNKSTPMS is smaller than the threshold value STPMR #, the process proceeds to step S43, and the most retarded learning value BASLRNR of the operating angle center phase of the intake valve 105 of the right bank is advanced to advance the center phase of the right bank. Is reduced by a predetermined value HSTPV #.
The center phase of the intake valve operating angle is measured as the phase angle from the reference crank angle position to the reference cam angle position, and the actual phase angle is subtracted from the most retarded angle learning value BASLRNR (phase angle at the most retarded angle). The result is calculated as the advance amount from the most advanced position, and feedback control is performed so that the advance amount matches the target.

The amount of air is reduced by so-called early closing control by advancing the central phase of the operating angle of the intake valve and the closing timing of the intake valve before the intake bottom dead center.
Therefore, if the most retarded learning value BASLRNR is set to decrease by the predetermined value HSTPV #, the advance amount is detected to be smaller, and the advance is made to compensate for the decrease.
By correcting the center phase of the intake valve of the right bank to the advance side, the amount of air in the right bank that is larger than the left bank is corrected to decrease, and the torque step between the banks is reduced.

Instead of decreasing the most retarded learning value BASLRNR by the predetermined value HSTPV #, the advance angle target value VTCTRGR of the operating angle center phase of the intake valve 105 of the right bank is corrected to increase by the predetermined value HSTPV # to further advance. You may correct to the corner side.
On the other hand, if it is determined in step S42 that the torque step BNKSTPMS is greater than or equal to the threshold value STPMR #, the process proceeds to step S44.

In step S44, it is determined whether or not the torque step BNKSTPMS is larger than a threshold value STPML # (> 0).
When the torque step BNKSTPMS is larger than the threshold value STPML #, it means that the MISC average value of the right bank is larger than the MISC average value of the left bank. In other words, the center phase in the right bank is more than the left bank. Advancing, indicating that the amount of air is smaller on the right bank side.

Therefore, when the torque step BNKSTPMS is larger than the threshold value STPML #, the process proceeds to step S45, where the most retarded learning value BASLRNL of the operating angle center phase of the intake valve 105 of the left bank is set to be decreased by a predetermined value HSTPV # or The advance target value VTCTRL of the operating angle center phase of the intake valve 105 of the bank is increased and corrected by a predetermined value HSTPV #.
As a result, the center phase of the intake valve of the left bank is corrected to the more advanced side, the amount of air in the left bank larger than the right bank is corrected to decrease, and the torque step between the banks is reduced.

  As described above, the torque step between banks in the region where ValveAA / Ne / Vol is greater than or equal to the first threshold LRNAACET # and the central phase of the operating angle of the intake valve 105 greatly affects the passing gas amount is variable valve timing. Judging that the variation in the center phase between the left and right banks due to the variation in the mechanisms 113a and 113b is the cause, the center phase of each bank is corrected in a direction in which the torque step between the banks is reduced.

When STPMR # ≦ BNKSTPMS ≦ STPML # and it is determined that the torque step between the banks is sufficiently small, the process proceeds to step S46, where 1 is set to the center phase learning end flag FCNTLRN.
On the other hand, if it is determined in step S41 that ValveAA / Ne / Vol is smaller than the first threshold value LRNAACET #, the process proceeds to step S47.

In step S47, it is determined whether or not 1 is set to the flag FCNTLRN, that is, whether or not the variation learning of the variable valve timing mechanisms 113a and 113b (center phase) has been completed.
When the flag FCNTLRN is 0 and the variation learning of the variable valve timing mechanisms 113a and 113b (center phase) is not completed, the routine is terminated without executing the lift learning after step S48.

Therefore, after the learning of the center phase is completed, the learning after step S48 is performed.
If it is determined in step S47 that the flag FCNTLRN is 1 and the variation learning of the variable valve timing mechanisms 113a and 113b (center phase) has been completed, the process proceeds to step S48.

In step S48, it is determined whether or not ValveAA / Ne / Vol is equal to or smaller than a second threshold value LRNAALFT # (≦ first threshold value LRNAACET #).
The region where ValveAA / Ne / Vol is equal to or smaller than the second threshold value LRNAALFT # is a region (A) where the amount of gas passing through the intake valve 105 changes with respect to the change in the opening area of the intake valve 105, as shown in FIG. In addition, this is a region where the amount of passing gas changes depending on the center phase of the operating angle of the intake valve 105.

However, since the variation in the air amount due to the variation in the center phase of the operating angle of the intake valve 105 has already been learned, the torque step between the banks in such a region has a lift characteristic due to the variable lift mechanisms 112a and 112b. It is determined that this is due to variations in (lift amount and operating angle).
Therefore, when it is determined that the ValveAA / Ne / Vol is equal to or less than the second threshold value LRNAALFT #, the process proceeds to step S49 and subsequent steps, and the variation learning of the lift characteristics (lift amount and operating angle) by the variable lift mechanisms 112a and 112b is learned. I do.

On the other hand, when the ValveAA / Ne / Vol is larger than the second threshold value LRNAALFT #, it corresponds to the non-learning region (C) shown in FIG. 9, and this routine is terminated as it is.
First, in step S49, as in step S42, it is determined whether or not the torque level difference BNKSTPMS is smaller than a threshold value STPMR # (<0).
When the torque step BNKSTPMS is smaller than the threshold value STPMR #, it indicates that the air amount is larger on the right bank side, so that the process proceeds to step S50, and the lift amount of the intake valve of the left bank is corrected to be larger. To do.

  More specifically, the left bank minimum lift learning value VSLRNL is corrected to increase by a predetermined value HSTPL #, or the left bank lift amount target value VELTRGL is corrected to increase by a predetermined value HSTPL #. When the minimum lift learning value VSLRNL is increased and corrected by the predetermined value HSTPL #, the increase amount of the lift amount as a deviation between the actually measured value and the minimum lift learning value VSLRNL is apparently reduced, and the lift amount is controlled to be larger. It will be.

On the other hand, when the torque step BNKSTPMS is greater than or equal to the threshold value STPMR #, the process proceeds to step S51, and it is determined whether or not the torque step BNKSTPMS is greater than the threshold value STPML # (> 0).
If the torque step BNKSTPMS is larger than the threshold value STPML #, the process proceeds to step S52, and the minimum lift learning value VSLRNR in the right bank is increased by a predetermined value HSTPL # to correct the lift amount of the intake valve in the right bank to be larger. Correct or increase the target value VELTRGR of the lift amount of the right bank by a predetermined value HSTPL #.

The flowchart of FIG. 10 shows control for correcting the torque step between banks based on the torque step BNKSTPIC obtained in the flowchart of FIG.
Here, the flowchart of FIG. 10 differs from the flowchart of FIG. 8 only in steps S62, 64, 69, and 71, and the other steps are the same as the flowchart of FIG.

Since the torque step BNKSTPIC is calculated as a positive value when the air amount in the right bank is larger than that in the left bank, it is determined in step S62 whether the torque step BNKSTPIC is larger than a threshold value STPIR # (> 0). Is determined.
When BNKSTPIC> STPIR #, the process proceeds to step S63 in order to advance the center phase in the right bank more (to reduce the amount of air in the right bank).

On the other hand, in step S64, it is determined whether or not the air amount in the left bank is larger than that in the right bank by determining whether or not the torque step BNKSTPIC is smaller than the threshold value STPIL # (<0).
If BNKSTPIC <STPIL #, the process proceeds to step S65 in order to further advance the center phase in the left bank (in order to reduce the air amount in the left bank).

Similarly, if it is determined in step S69 that BNKSTPIC> STPIR #, the process proceeds to step S70 to increase the lift amount (air amount) in the left bank, and if it is determined in step S71 that BNKSTPIC <STPIL #, the right The process proceeds to step S72 in order to increase the lift amount (air amount) in the bank.
The flowchart in FIG. 11 shows control for correcting the torque step between banks based on the torque step BNKSTPAL obtained in the flowchart in FIG.

Here, the flowchart of FIG. 11 differs from the flowchart of FIG. 8 only in steps S82, 84, 89, and 91, and the other steps are processed in the same manner as the flowchart of FIG.
The air-fuel ratio feedback correction coefficient ALPHAH is set to a larger value as the air amount is larger than the fuel amount and the air-fuel ratio becomes leaner, and the torque step BNKSPAL is larger when the air amount in the right bank is larger than that in the left bank. Since the value is calculated as a positive value, in step S82, it is determined whether or not the torque step BNKSTPAL is larger than a threshold value STPIR # (> 0).

When BNKSTPAL> STPIR #, the process proceeds to step S83 in order to advance the center phase in the right bank more (to reduce the amount of air in the right bank).
On the other hand, in step S84, it is determined whether or not the amount of air in the left bank is larger than that in the right bank by determining whether or not the torque level difference BNKSTPAL is smaller than the threshold value STPIL # (<0).

If BNKSTPAL <STPIL #, the process proceeds to step S85 in order to further advance the center phase in the left bank (in order to reduce the air amount in the left bank).
Similarly, if it is determined in step S89 that BNKSTPAL> STPIR #, the process proceeds to step S90 to increase the lift amount (air amount) in the left bank, and if it is determined in step S91 that BNKSTPAL <STPIL #, Proceed to step S92 to increase the lift amount (air amount) in the bank.

  By the way, in the said embodiment, it was set as the structure which distinguishes the area | region which learns the dispersion | variation in the said variable lift mechanisms 112a and 112b, and the area | region which learns the dispersion | variation in the variable valve timing mechanisms 113a and 113b on the basis of the opening area of an intake valve. However, the learning region can be determined based on the gas flow velocity passing through the intake valve as a state quantity correlated with the opening area.

  That is, a region for learning the variation of the variable lift mechanisms 112a and 112b is set in the region where the gas flow velocity passing through the intake valve is sonic, and the variable valve timing mechanism 113a, The region for learning the variation of 113b is set, and the variation learning of the variable lift mechanisms 112a and 112b is performed after the variation learning of the variable valve timing mechanisms 113a and 113b is completed, as in the above embodiment.

Whether the gas flow velocity passing through the intake valve is sonic or non-sonic can be determined by detecting the front-rear pressure of the intake valve.
Then, each step of comparing the ValveAA / Ne / Vol and the threshold value is rewritten into a process for determining whether the gas flow velocity passing through the intake valve is sonic or non-sonic, thereby changing the variable lift mechanism 112a, The variation of 112b and the variation of the variable valve timing mechanisms 113a and 113b can be learned separately.

The first and second threshold values to be compared with the ValveAA / Ne / Vol may be the first threshold value LRNAACET # = the second threshold value LRNAALFT #, but the second threshold value LRNAALFT # <the first threshold value LRNAACET # By providing the non-learning region, it is possible to avoid erroneous learning in a region where the change in the passing gas amount is not stable with respect to the change in the opening area of the intake valve 105.
In the above embodiment, the variation in the air amount between the banks of the V-type engine is corrected. However, for example, in a series engine, the deviation of the actual intake air amount with respect to the intake air amount predicted from the operation amount of the variable valve mechanism. Can be learned separately for each region depending on the center phase and those depending on the lift characteristics, and such learning can be performed for each bank in a V-type or horizontally opposed engine.

Here, the technical ideas other than claim that may be grasped from the above embodiment will be described effects co below.

(A) In the control apparatus for a variable valve mechanism according to any one of claims 1 to 3 ,
The control apparatus for a variable valve mechanism, wherein the internal combustion engine has a plurality of banks, and the control characteristics of the center phase and the lift characteristic are corrected in each bank so as to reduce a torque step between the banks. .

According to such a configuration, the torque step between banks due to the variation in the center phase or lift characteristics is learned by dividing the operation region into the variation due to the center phase and the variation due to the lift characteristics. To eliminate.

(B) In the control apparatus for a variable valve mechanism according to claim 1, the operation for learning the variation in the air amount depending on the center phase based on the opening area of the intake valve or a state quantity correlated with the opening area. A control device for a variable valve mechanism, characterized in that the control device is divided into a region and an operation region in which variation in air amount depending on the lift characteristics is learned.
According to such a configuration, the operating region in which the amount of gas passing through the intake valve changes according to the opening area of the intake valve or a state quantity that correlates to the opening area, and the state that correlates to the opening area of the intake valve or the opening area Since there is an operating region that does not change according to the amount, the operating region that learns the variation in the central phase of the operating angle and the variation in the lift characteristics are determined according to the opening area of the intake valve or the state quantity that correlates to the opening area. Divide it into driving areas to learn.
Therefore, it is possible to learn with high accuracy by separating the variation in the center phase of the operating angle and the variation in lift characteristics.

(C) In the control apparatus for a variable valve mechanism according to claim (b), air that depends on the central phase in an operating region in which an opening area of the intake valve or a state quantity correlated with the opening area is larger than a threshold value Learning an amount variation, and learning an air amount variation depending on the lift characteristics in an operating region where the opening area of the intake valve or a state quantity correlated with the opening area is at least smaller than the threshold value. Control device for variable valve mechanism.
According to such a configuration, in the operation region where the opening area of the intake valve is small, the amount of gas passing through the intake valve changes according to the opening area of the intake valve, but when the opening area of the intake valve increases, the amount of gas passing through the intake valve Does not change according to the opening area of the intake valve, and the amount of passing gas changes depending on the center phase (valve closing timing) of the operating angle of the intake valve. A distinction is made between an operation region in which the variation in the center phase of the operating angle is learned and an operation region in which the variation in lift characteristics is learned.
Accordingly, it is possible to accurately learn the variation in the air amount depending on the variation in the center phase of the operating angle and the variation in the air amount depending on the variation in the lift characteristics.
(D) In the control device for a variable valve mechanism according to claim (b) or (c) ,
A control apparatus for a variable valve mechanism, wherein ValveAA / Ne is calculated as a state quantity correlated with the opening area of the intake valve, where ValveAA is the opening area of the intake valve and Ne is the engine speed.

  According to such a configuration, the learning area can be set with high accuracy corresponding to the change of the appropriate learning area due to the difference in the engine speed.

The block diagram of the internal combustion engine in embodiment of this invention. The perspective view which shows the structure of the variable lift mechanism in the said embodiment. The side view of the said variable lift mechanism. Sectional drawing which shows the variable valve timing mechanism in the said embodiment. The flowchart which shows 1st Embodiment of the means to detect the torque level difference between banks. The flowchart which shows 2nd Embodiment of the means to detect the torque level difference between banks. The flowchart which shows 3rd Embodiment of the means to detect the torque level difference between banks. The flowchart which shows 1st Embodiment of learning control of the air quantity dispersion | variation between banks. The diagram which shows the area | region division of air quantity dispersion | variation learning. The flowchart which shows 2nd Embodiment of the learning control of the air quantity dispersion | variation between banks. The flowchart which shows 3rd Embodiment of the learning control of the air quantity dispersion | variation between banks.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Internal combustion engine, 104 ... Electronic control throttle, 105 ... Intake valve, 107 ... Exhaust valve, 111a, 111b ... Oxygen sensor, 112a, 112b ... Variable lift mechanism, 113a, 113b ... Variable valve timing mechanism, 114 ... Electronic control unit (ECU)

Claims (3)

A control device for a variable valve mechanism that varies a center phase of an operating angle of an intake valve of an internal combustion engine and a lift characteristic of the intake valve,
The air amount depending on the center phase and the air amount variation depending on the lift characteristics are individually learned by dividing the operation region based on the state quantity of the intake system, and the air depending on the center phase the amount since variation learning is completed, the control device of the variable valve mechanism, characterized in that to learn the variation in the amount of air dependent on the lift characteristics. In the operation region where the gas flow velocity passing through the intake valve is a sonic velocity, an operation region for learning the variation in the air amount depending on the lift characteristics is set, and in the operation region where the gas flow velocity is a non-sonic velocity, 2. The control device for a variable valve mechanism according to claim 1, wherein an operation region in which a variation in the air amount depending on the center phase is learned is set . 2. A non-learning region is set between an operation region in which variation in air amount depending on the center phase is learned and an operation region in which variation in air amount depending on the lift characteristic is learned. Or the control apparatus of the variable valve mechanism of 2.

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