JP4426993B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention has a plurality of banks, and each bank is provided with a variable valve mechanism that varies the center phase of the operating angle of the intake valve and the lift characteristic of the intake valve, respectively. About.

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 cam shaft phase difference 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 of the variable range cannot be absorbed. For example, in a V-type engine, when each valve has an intake valve mechanism having a variable valve mechanism, the amount of air (generated torque) between the banks is reduced. Deviations occur, reducing the stability of engine rotation and the quietness of the engine.

  Therefore, it is desirable to learn the variation in the air amount between banks and to correct the operation amount of the variable valve mechanism of each bank, but the lift characteristics (lift amount and / or operating angle) of the engine valve are variable. And a variable valve timing mechanism that combines a variable valve timing mechanism that adjusts the phase difference of the camshaft with respect to the crankshaft, the air amount is both the lift characteristic and the center phase of the operating angle. Therefore, there is 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-described problems, and in an internal combustion engine provided with each bank a variable valve mechanism that makes the center phase of the operating angle of the intake valve and the lift characteristic of the intake valve variable. The air volume variation between the banks can be separated into the variation depending on the center phase of the operating angle and the variation depending on the lift characteristics, and the variation in the air amount between banks can be accurately corrected to generate torque generated between the banks. It is an object of the present invention to provide a control device for an internal combustion engine that can prevent the occurrence of a step in the internal combustion engine.

Therefore, the invention described in claim 1 has a plurality of banks, and each bank is provided with a variable valve mechanism that makes the operating valve center angle and the lift characteristic of the intake valve variable. A control device for an internal combustion engine, wherein an air amount variation between banks depending on the center phase and an air amount variation between banks depending on the lift characteristics are divided into regions based on an intake system state amount. The learning is performed individually , and after the variation learning of the air amount depending on the center phase is completed, the variation of the air amount depending on the lift characteristic is learned , and the air amount depending on the center phase The internal combustion engine is configured so that the torque generated in each bank is equal until the learning of the variation and the variation in the air amount depending on the lift characteristics is completed. The operation amount was configured to be corrected for each bank.

According to such a configuration, a region that is greatly affected by variations in the opening area of the intake valve and a region that is greatly affected by variations in the center phase (valve closing timing) of the operating angle of the intake valve are determined according to the state quantity of the intake system. In each area, the air amount variation between banks is individually learned, but the variation learning of the lift characteristics is learned after the learning of the air amount variation depending on the center phase is completed and the influence of the center phase is eliminated. . Further, until the learning is completed , the engine operation amount is corrected for each bank so that the torque generated in each bank becomes equal.

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 it is possible to accurately correct the air amount variation between the banks, and to stabilize the engine rotation. Silence can be improved, and it is possible to avoid the occurrence of a torque step between banks until learning is completed.
According to a second aspect of the present invention, a region for learning variation in the air amount depending on the lift characteristics is set in a region where the gas flow velocity passing through the intake valve is sonic velocity, and the gas flow velocity becomes non-sonic velocity. In the region, a region for learning the variation in the air amount depending on the center phase is set .

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 accurately learn the variation in the air amount depending on the center phase of the operating angle and the variation in the air amount depending on the lift characteristics.
According to a third aspect of the present invention, the correction amount of the ignition timing for each bank is variably set according to the air amount difference between the banks so that the generated torque of each bank becomes equal.
According to such a configuration, until the air variation between the banks is eliminated, the ignition timing is corrected for each bank, and even if there is an air amount difference between the banks, a large difference in generated torque does not occur. Like that.

  Therefore, the generated torque in each bank can be corrected with good response and the generated torque in each bank can be kept equal until the variation in the air amount between banks due to the variation in the variable valve mechanism is eliminated.

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 the air amount variation between banks.

When the processing shown in the flowchart of FIG. 5 is executed, it is assumed that an air flow meter 115 for the right bank and an air flow meter 115 for the left bank that measure the intake air flow rate individually 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. 6 shows a second embodiment in which the air-fuel ratio step between banks is obtained as the air amount variation.
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. 7 shows the control for correcting the air amount variation between banks based on the filling efficiency step BNKSTPIC between banks obtained in the flowchart in FIG.
In step S61, 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 greater than the first threshold LRNAACET # is shown in FIG. 8 when the intake valve 105 passes through the change in the opening area of the intake valve 105. 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.

When ValveAA / Ne / Vol is greater than or equal to the first threshold value LRNAACET #, the process proceeds to step S62, where it is determined whether or not the step BNKSTPIC is greater than the threshold value STPIR # (> 0).
Since the torque step BNKSTPIC is calculated to be 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 that the torque step BNKSTPIC is larger than the threshold value STPIR # (> 0). Then, the process proceeds to step S63 in order to reduce the air amount in the right bank.

In step S63, the most retarded learning value BASLRNR of the operating angle center phase of the intake valve 105 of the right bank is set to be decreased by a predetermined value HSTPV # in order to advance the center phase of the right bank.
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 variation in air amount between 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 S62 that the step BNKSTPIC is equal to or less than the threshold value STPMR #, the process proceeds to step S64.

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 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).
In step S65, the most retarded learning value BASLRNL of the operating angle center phase of the intake valve 105 in the left bank is set to be decreased by a predetermined value HSTPV #, or the advance angle target value VTCTRL of the operating angle center phase of the intake valve 105 in the left bank Is increased 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 air amount of the left bank larger than the right bank is corrected to decrease, and the air amount variation between banks is reduced.
As described above, the variation in the air amount 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 It is determined that the variation in the central phase in the left and right banks due to the variation in the timing mechanisms 113a and 113b is caused, and the central phase in each bank is corrected in a direction in which the variation in the air amount between the banks is reduced.

When STPMR # ≦ BNKSTPIC ≦ STPML # and it is determined that the air amount variation between banks is sufficiently small, the process proceeds to step S66, where 1 is set to the center phase learning end flag FCNTLRN.
On the other hand, if it is determined in step S61 that ValveAA / Ne / Vol is smaller than the first threshold value LRNAACET #, the process proceeds to step S67.

In step S67, it is determined whether or not the flag FCNTLRN is set to 1, that is, whether or not the variation learning of the variable valve timing mechanisms 113a and 113b (center phase) has been completed.
If the flag FCNTLRN is 0 and the variation learning of the variable valve timing mechanisms 113a and 113b (center phase) has not been completed, the routine is terminated without executing the lift learning after step S68.

Therefore, after the learning of the center phase is completed, the learning after step S68 is performed.
If it is determined in step S67 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 S68.

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 less than or equal to the second threshold 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 variation in the air amount between banks in the region is lifted by the variable lift mechanisms 112a and 112b. It is determined that this is due to variations in characteristics (lift amount and operating angle).
Therefore, if it is determined that the ValveAA / Ne / Vol is equal to or smaller than the second threshold value LRNAALFT #, the process proceeds to step S69 and subsequent steps, and learning of variation in lift characteristics (lift amount and operating angle) by the variable lift mechanisms 112a and 112b. 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. 8, and this routine is terminated as it is.
First, in step S69, as in step S62, it is determined whether or not the step BNKSTPIC is larger than a threshold value STPIR # (> 0).
When the step BNKSTPIC is larger than the threshold value STPIR # (> 0), it indicates that the air amount is larger on the right bank side, so the process proceeds to step S70, and the lift amount of the intake valve of the left bank is set. Correct bigger.

  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 actual measurement value and the minimum lift learning value VSLRNL is apparently decreased, and the lift amount is controlled to be larger. It will be.

On the other hand, when the step BNKSTPIC is equal to or smaller than the threshold value STPIR #, the process proceeds to step S71, and it is determined whether or not the step BNKSTPIC is smaller than the threshold value STPML #.
If the torque step BNKSTPIC is smaller than the threshold value STPML #, the process proceeds to step S72, and the right bank minimum lift learning value VSLRNR is increased by a predetermined value HSTPL # to correct the lift amount of the right bank intake valve to be larger. Correct or increase the target value VELTRGR of the lift amount of the right bank by a predetermined value HSTPL #.

Thereby, the variation in the air amount between banks due to the variation between the banks of the variable lift mechanisms 112a and 112b (lift amount and operating angle) is eliminated.
The flowchart in FIG. 9 shows the control for correcting the air amount variation between banks based on the step BNKSPAL obtained in the flowchart in FIG.
Here, the flowchart of FIG. 9 differs from the flowchart of FIG. 7 only in steps S82, 84, 89, and 91, and the other steps are performed 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 it 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 present embodiment, the ignition timing correction shown in the flowchart of FIG. 10 is performed so that the torque step between the banks is not left until the variation learning between the banks of the variable valve mechanism is completed. Execute.
The ignition timing correction according to the flowchart of FIG. 10 corresponds to a configuration in which the step BNKSTPIC is detected according to the flowchart of FIG. 5 and variation learning is performed according to the flowchart of FIG.

First, in step S101, it is determined whether or not the variation learning between the banks of the central phase of the operating angle has been completed.
Whether or not the center phase variation learning has ended can be determined based on the learning end flag FCNTLRN.
In the present embodiment, as shown in the flowchart of FIG. 7 or FIG. 9, since the variation learning of the lift characteristic is performed after the learning of the variation of the center phase is completed, when the variation learning of the center phase is not finished, This means that the variation learning has not been completed.

Therefore, if it is determined in step S101 that the variation learning of the center phase has not ended, a torque step may be generated between the banks due to the variation in the air amount between the banks, so that the ignition timing is corrected. Therefore, the process proceeds to step S103.
On the other hand, if it is determined in step S101 that the center phase variation learning has been completed, the process proceeds to step S102 to determine whether or not the lift characteristic variation learning has been completed.

When the flow proceeds to step S71 or step S91 in the flowchart of FIG. 7 or FIG. 9, and NO is determined in step S71 or step S91 and the routine is terminated bypassing step S72 or step S92, the lift characteristics It is determined that the variation learning of has been completed.
If it is determined in step S102 that the variation learning of the lift characteristic has been completed, the air amount variation between banks due to the variation of the variable valve mechanisms (variable lift mechanisms 112a and 112b and variable valve timing mechanisms 113a and 113b). Since it is not necessary to eliminate the torque step between the banks by correcting the ignition timing, this routine is terminated as it is.

On the other hand, if it is determined in step S102 that the variation learning of the lift characteristics has not ended, the variation in the center phase is learned and corrected, but there is still a variation in the air amount between the banks due to the variation in the lift characteristics. Therefore, the process proceeds to step S103 to correct the ignition timing.
In step S103, it is determined whether or not the step BNKSTPIC is larger than a threshold value STPIR # (> 0).

When the step BNKSTPIC is larger than the threshold value STPIR #, the air amount is larger on the right bank side, so the process proceeds to step S104, the ignition timing on the right bank side is retarded, and the generated torque on the right bank is increased. Correction to decrease
On the other hand, when the step BNKSTPIC is equal to or smaller than the threshold value STPIR #, the process proceeds to step S105, and it is determined whether or not the step BNKSTPIC is smaller than the threshold value STPIL # (<0).

When the step BNKSTPIC is smaller than the threshold value STPIL #, the air amount is larger on the left bank side, so the process proceeds to step S106, the left bank side ignition timing is retarded, and the left bank generated torque Correction to decrease
In the retard correction of the ignition timing in the steps S104 and S106, as shown in FIG. 11, the retard correction amount is increased as the absolute value of the step BNKSTPIC increases, that is, the variation in the air amount increases. .

If the ignition timing is corrected as described above, it is possible to avoid a torque step between the banks until the variation between the banks of the variable valve mechanism is learned. Can maintain sex.
Next, the ignition timing correction control corresponding to the configuration in which the step BNKSTPAL is detected according to the flowchart of FIG. 6 and the variation learning is performed according to the flowchart of FIG. 9 will be described with reference to the flowchart of FIG.

  The flowchart of FIG. 12 performs the same processing as each step of the flowchart of FIG. 10 except that the parameter to be compared with the threshold value in steps S113 and S115 is the step BNKSTPAL, and the characteristics of the retardation correction amount with respect to the step BNKSTPAL. Also, as shown in FIG. 13, the characteristics of the retardation correction amount with respect to the step BNKSTPIC shown in FIG. 11 are the same.

In the above embodiment, the region for learning the variation of the variable lift mechanisms 112a and 112b and the region for learning the variation of the variable valve timing mechanisms 113a and 113b are distinguished based on the opening area of the 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, A 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 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.
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 device for an internal combustion engine according to any one of claims 1 to 3 ,
A control device for an internal combustion engine, wherein a non-learning region is set between a region for learning variation in air amount depending on the center phase and a region for learning variation in air amount depending on the lift characteristics. .

According to such a configuration, learning is performed in a region where the characteristics are unstable between a region where the air amount changes depending on the center phase and a region where the air amount changes depending on the center phase and the lift characteristics. Prevent mis-learning.

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 air amount dispersion | variation between banks. The flowchart which shows 2nd Embodiment of the means to detect the air amount dispersion | variation 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 1st Embodiment of ignition timing correction | amendment before the learning of the air quantity dispersion | variation between banks is completed. The diagram which shows the characteristic of the ignition timing correction amount in the flowchart of FIG. The flowchart which shows 2nd Embodiment of ignition timing correction | amendment before the learning of the air quantity dispersion | variation between banks is completed. The diagram which shows the characteristic of the ignition timing correction amount in the flowchart of FIG.

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 an internal combustion engine having a plurality of banks, each bank including a variable valve mechanism that varies a center phase of an operating angle of an intake valve and a lift characteristic of the intake valve,
A configuration in which the variation in the air amount between banks depending on the center phase and the variation in the air amount between banks depending on the lift characteristics are separately learned by dividing the region based on the state amount of the intake system , and After learning the variation in the air amount depending on the center phase, learning the variation in the air amount depending on the lift characteristics ,
Until the learning of the variation in the air amount depending on the center phase and the variation in the air amount depending on the lift characteristics is completed, the operation amount of the internal combustion engine is set so that the generated torque of each bank becomes equal. A control apparatus for an internal combustion engine, wherein correction is performed for each bank. In the region where the gas flow velocity passing through the intake valve is sonic, a region for learning the variation in the air amount depending on the lift characteristics is set, and in the region where the gas flow velocity is non-sonic, the central phase is set. The control device for a variable valve mechanism according to claim 1, wherein a region for learning the variation of the dependent air amount is set . The internal combustion engine according to claim 1 or 2 , wherein the correction amount of the ignition timing for each bank is variably set according to the air amount difference between the banks so that the generated torque of each bank becomes equal. Control device.

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