JP5015710B2 - Intake air amount control device for internal combustion engine - Google Patents

Description

  The present invention controls the intake air amount of an internal combustion engine for controlling the intake air amount of the engine by controlling the lift characteristic of the intake valve and the opening of the intake throttle valve interposed in the intake passage upstream of the intake valve. Relates to the device.

Japanese Patent Laid-Open No. 2004-151867 discloses that an intake air amount (mass flow rate) detected by an air flow sensor and an intake air amount (volume flow rate) calculated based on a throttle opening detected by a throttle sensor are opened by the throttle sensor. It is described that learning of a correction value for correcting the degree detection value corrects variations in the throttle sensor and deterioration over time, thereby ensuring the accuracy of opening detection.
JP-A-8-074650

  By the way, in an internal combustion engine provided with a variable valve mechanism that makes the intake valve lift characteristics (such as the maximum valve lift amount and the central phase of the operating angle) variable together with the throttle valve, the intake air amount of the engine also depends on the lift characteristics. Therefore, even if the throttle opening can be controlled with high accuracy, the intake air amount may vary due to variations in the lift characteristics, and when learning the correlation between the throttle opening and the intake air amount, When affected by variations in characteristics, there arises a problem that learning accuracy decreases.

  The present invention has been made in view of the above problems, and the control error of the intake air amount due to the lift characteristic of the intake valve and the control error of the intake air amount due to the opening of the intake throttle valve are mutually affected. An object of the present invention is to improve the control accuracy of the intake air amount in an internal combustion engine provided with a variable valve mechanism that makes the lift characteristics of the intake valve variable together with the throttle valve.

Therefore, an intake air amount control apparatus for an internal combustion engine according to the first aspect of the present invention includes a variable lift mechanism that makes the maximum valve lift amount of the intake valve variable, and a variable valve that makes the center phase of the operating angle of the intake valve variable. A variable valve mechanism including a timing mechanism, an intake throttle valve interposed in an intake passage upstream of the intake valve, a maximum valve lift amount of the intake valve, a center phase of an operating angle of the intake valve, and the intake throttle The control means for controlling the opening degree of the valve to control the intake air amount of the engine, and the opening degree of the intake throttle valve when the flow rate of the intake air passing through the intake throttle valve is substantially sonic. When the first learning means for learning the intake air amount control error due to the intake air flow rate and the non-sonic velocity of the intake air passing through the intake throttle valve are in a non-sonic speed condition, The second learning means for individually learning the error of the air amount control and the error of the intake air amount control due to the center phase of the operating angle of the intake valve, and the learning result by the first learning means and the second learning means. And a correction means for correcting the control of the maximum valve lift amount of the intake valve, the central phase of the operating angle of the intake valve, and the opening degree of the intake throttle valve by the control means,
The second learning means is
Suction passing through the intake valve in a state where the variable lift mechanism is controlled so that the maximum valve lift amount is a learning lift amount so that the flow velocity of the intake air passing through the intake valve is substantially sonic. When the flow velocity of air becomes substantially sonic, the learning lift amount is learned by learning an intake air amount control error based on the maximum valve lift amount of the intake valve based on the intake air amount at the learning lift amount. If the flow rate of the intake air passing through the intake valve does not become nearly sonic speed even if the variable lift mechanism is controlled so that the center angle of the operating angle of the intake valve is delayed by the variable valve timing mechanism. The maximum valve lift of the intake valve is moved based on the intake air amount when the center phase is the most retarded angle position and the maximum valve lift amount is the learning lift amount. A lift learning means for learning the error of the intake air amount control by the quantity,
After learning by the lift learning means, and when the flow velocity of the intake air passing through the intake valve is non-sonic, the intake air amount control error due to the center phase of the operating angle of the intake valve Valve timing learning means for learning
It is characterized by including .
According to the above invention, depending on whether or not the flow velocity of the intake air passing through the intake throttle valve is substantially sonic, the control error of the intake air amount due to the opening of the intake throttle valve is learned, or the intake due to the lift characteristic of the intake valve Whether to learn the control error of the air amount is switched.

When the flow rate of the intake air passing through the intake throttle valve is substantially sonic, the intake air amount is controlled by the opening (opening area) of the intake throttle valve, and the lift characteristic of the intake valve disposed downstream of the intake throttle valve Therefore, the control error of the intake air amount due to the opening of the intake throttle valve can be learned with high accuracy.
Furthermore, when the flow velocity of the intake air passing through the throttle is non-sonic, the control error of the intake air amount due to the maximum valve lift amount of the intake valve and the control error of the intake air amount due to the center phase of the intake valve operating angle are respectively shown. After learning the intake air amount control error due to the maximum valve lift amount of the intake valve, with the flow rate of the intake air passing through the intake valve being approximately the sound speed, and performing such learning, In addition, an intake air amount control error based on the center phase of the operating angle of the intake valve is learned under the condition that the flow velocity of the intake air passing through the intake valve is non-sonic.
That is, when the flow velocity of the intake air passing through the intake valve is substantially sonic, the intake air amount changes depending on the opening area of the intake valve, so that the control error of the intake air amount due to the maximum valve lift amount of the intake valve is reduced. After learning and performing such learning, and when the flow velocity of the intake air passing through the intake valve is non-sonic, the intake air amount depends on the center phase (opening / closing timing) of the operating angle of the intake valve. Therefore, the control error of the intake air amount due to the center phase of the operation angle of the intake valve is learned.
Here, when learning the intake air flow rate control error due to the maximum valve lift of the intake valve, if the flow velocity of the intake air passing through the intake valve cannot be made nearly sonic, it can be changed by the variable valve timing mechanism. The intake air amount is controlled by the maximum valve lift amount of the intake valve by moving the center phase of the working angle to the most retarded angle position to avoid variations in the actual intake air amount due to the difference in the center phase. To learn the error.

According to a second aspect of the present invention, the second learning means sets a reference value of the intake air amount at that time based on the maximum valve lift amount and the center phase of the intake valve , and the reference value and the actual intake air The deviation from the quantity was calculated.

According to the above invention, when the maximum valve lift amount and the center phase of the intake valve are variably controlled, the reference value of the intake air amount is set based on the maximum valve lift amount and the center phase of the intake valve.
According to a third aspect of the present invention, an exhaust side variable valve timing mechanism is provided which makes the central phase of the exhaust valve operating angle variable, and the second learning means has the exhaust valve together with the maximum valve lift amount and the central phase of the intake valve. The reference value of the intake air amount at that time is set based on the center phase of the operating angle.

According to the above invention, when the maximum valve lift amount and the center phase of the intake valve are variable and the center phase of the exhaust valve operating angle is variable, the reference value of the intake air amount is set to the maximum value of the intake valve. It is set based on the valve lift amount, the center phase, and the center phase of the exhaust valve operating angle, and the deviation of the actual value from the reference value is taken as the control error.

According to a fourth aspect of the present invention, the first learning means has a reference value of the intake air amount set from the opening of the intake throttle valve under the condition that the flow velocity of the intake air passing through the intake throttle valve is substantially sonic. The deviation from the actual intake air amount at that time was calculated.
According to the above invention, the difference between the reference value of the intake air amount set from the opening of the intake throttle valve and the actual intake air amount indicates a control error of the intake air amount based on the opening of the intake throttle valve. become.

According to a fifth aspect of the present invention, the first and second learning means determine whether or not the flow rate of the intake air passing through the intake throttle valve is a condition that the sound speed is substantially sonic. Judgment was made based on the intake pressure.
According to the above invention, since the upstream side of the intake throttle valve is at atmospheric pressure, the intake pressure when the flow velocity of the intake air passing through the intake throttle valve is substantially sonic is specified, and the intake pressure is within the specified region. It is determined whether or not the flow velocity of the intake air passing through the intake throttle valve is substantially sonic.

According to a sixth aspect of the present invention, the update of the learning correction value for correcting the air-fuel ratio of the internal combustion engine to the target air-fuel ratio is permitted on the condition that learning by the first and second learning means is experienced. An air-fuel ratio learning permission unit is provided.
According to the above invention, after learning the control error of the intake air amount due to the opening degree of the intake throttle valve and the control error of the intake air amount due to the lift characteristic of the intake valve, the accuracy of the intake air amount control is ensured. The update of the learning correction value for correcting the air-fuel ratio is permitted.

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 electronic control throttle device 104 that opens and closes a throttle valve (intake throttle valve) 103b by a throttle motor 103a is interposed in an intake pipe 102 of the internal combustion engine 101. The electronic control throttle device 104 and a downstream intake valve are provided. Air is sucked into the combustion chamber 106 through 105.

A fuel injection valve 131 is provided in the intake port 130 upstream of the intake valve 105 of each cylinder.
The fuel injection valve 131 is supplied with fuel adjusted to a predetermined pressure, and injects an amount of fuel proportional to the injection pulse width (valve opening time) of the injection pulse signal sent from the engine control module (ECM) 114. .

The air-fuel mixture in the combustion chamber 106 is ignited and burned by spark ignition by a spark plug (not shown).
The fuel injection valve 131 can be an in-cylinder direct injection internal combustion engine in which fuel is directly injected into the combustion chamber 106, and a compression self-ignition internal combustion engine can be used instead of the spark ignition internal combustion engine. it can.

The combustion exhaust in the combustion chamber 106 is discharged through an exhaust valve 107, purified by the front catalytic converter 108 and the rear catalytic converter 109, and then released into the atmosphere.
The exhaust valve 107 is driven to open and close by a cam 111 provided on the exhaust camshaft 110 while maintaining a constant maximum valve lift, valve operating angle, and valve timing.

On the other hand, the lift characteristic of the intake valve 105 is variable by a variable lift mechanism 112 and a variable valve timing mechanism 113 as variable valve mechanisms. The variable lift mechanism 112 determines the maximum valve lift amount of the intake valve 105 as a valve operating angle. In addition, when the maximum valve lift amount is increased (decreased) and changed, the valve operating angle is also increased (decreased) at the same time.

The variable valve timing mechanism 113 continuously changes the central phase of the valve operating angle of the intake valve 105 by changing the rotational phase of the intake valve drive shaft 3 to be described later with respect to the crankshaft 120. Mechanism.
The engine control module 114 incorporating the microcomputer sets the fuel injection amount (injection pulse width), the ignition timing, the target intake air amount, the target intake pipe negative pressure by arithmetic processing according to a program stored in advance. Based on these, a control signal is output to the fuel injection valve 131, a power transistor for the ignition coil (not shown), the electronic control throttle device 104, the variable lift mechanism 112, and the variable valve timing mechanism 113.

A unit for controlling the fuel injection amount and ignition timing of the internal combustion engine 101 and a unit for controlling the lift characteristics of the intake valve 105 by the variable lift mechanism 112 and the variable valve timing mechanism 113 can be provided separately.
Detection signals from various sensors are input to the engine control module 114.

  Examples of the various sensors include a hot wire type air flow sensor 115 that detects an intake air amount (mass flow rate) of the internal combustion engine 101, an accelerator sensor 116 that detects an opening degree of an accelerator pedal operated by a vehicle driver, and a crankshaft 120. A crank angle sensor 117 that outputs a unit crank angle signal POS for each unit crank angle, a throttle sensor 118 that detects an opening TVO of the throttle valve 103b, By detecting a water temperature sensor 119 for detecting the coolant temperature of the engine 101 and a detected portion provided on a signal plate supported by the intake valve drive shaft 3 described later, for each reference rotational position of the intake valve drive shaft 3. Cam sensor 132 that outputs a cam signal, atmospheric pressure sensor 13 that detects atmospheric pressure An intake pressure sensor 136 that detects an intake pipe internal pressure downstream of the throttle valve 103b, an air-fuel ratio sensor 137 that is disposed upstream of the front catalytic converter 108 and detects an air-fuel ratio from the oxygen concentration in the exhaust gas are provided. .

  The unit crank angle signal POS is generated on the signal plate so that a tooth loss occurs at every crank angle (180 ° CA for four cylinders) corresponding to the stroke phase difference (ignition interval) between the cylinders of the internal combustion engine 101. A detection unit is set, and the reference crank angle position REF for each stroke phase difference is detected by detecting the tooth missing position of the unit crank angle signal POS based on the output cycle of the unit crank angle signal POS. Be able to.

Then, from the phase difference between the cam signal from the cam sensor 132 and the reference crank angle position REF, the advance / retard angle amount of the valve timing (center phase of the operating angle) by the variable valve timing mechanism 113 is detected.
Further, the rotational speed NE of the internal combustion engine 101 is detected based on the detection interval time of the reference crank angle position REF.

FIG. 2 is a perspective view showing the structure of the variable lift mechanism 112. However, the variable lift mechanism 112 is not limited to the structure shown in FIG.
In the internal combustion engine 101 of the present embodiment, a pair of intake valves 105 is provided for each cylinder, and an intake valve drive shaft 3 that is rotationally driven by the crankshaft 120 is disposed above the intake valves 105 in the cylinder row direction. Is supported rotatably.

A swing cam 4 that contacts the valve lifter 105a of the intake valve 105 and opens and closes the intake valve 105 is fitted on the intake valve drive shaft 3 so as to be relatively rotatable.
A variable lift mechanism 112 for continuously changing the operating angle and valve lift amount of the intake valve 105 is provided between the intake valve drive shaft 3 and the swing cam 4.
In FIG. 2, the variable lift mechanism 112 is shown only on one side of the pair of intake valves 105, and the other side is not shown.

A variable valve timing mechanism that continuously changes the center phase of the operating angle of the intake valve 105 by changing the rotational phase of the intake valve drive shaft 3 with respect to the crankshaft 120 at one end of the intake valve drive shaft 3. 113 is arranged.
As shown in FIGS. 2 and 3, the variable lift mechanism 112 includes a circular drive cam 11 that is eccentrically fixed to the intake valve drive shaft 3 and a ring that is externally fitted to the drive cam 11 so as to be relatively rotatable. A link 12, a control shaft 13 that extends substantially parallel to the intake valve drive shaft 3 in the cylinder row direction, a circular control cam 14 that is eccentrically fixed to the control shaft 13, and a relative position 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 by a motor 17 via a gear train 18, and a preset minimum lift position / minimum is set by a stopper 13 a provided integrally with the control shaft 13 coming into contact with the fixed side. Further rotation to the lift / working angle decrease side is restricted at an angular position corresponding to the working angle position (hereinafter simply referred to as the minimum lift position).
With the above configuration, when the intake valve drive shaft 3 rotates in conjunction with the crankshaft 120, 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. The swing cam 4 swings through the rod-shaped link 16 and the intake valve 105 is driven to open and close.

Further, by driving and controlling the motor 17 to change 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 changes and the posture of the rocking cam 4 changes. .
As a result, the operating angle of the intake valve 105 and the maximum valve lift amount continuously change while the central phase of the operating angle of the intake valve 105 remains substantially constant.

A detection signal from an angle sensor 133 that detects the rotation angle of the control shaft 13 is input to the engine control module 114, and the control shaft 13 is rotated to a target angle position corresponding to a target valve lift amount. Based on the detection result of the angle sensor 133, the direction and magnitude of the current of the motor 17 are feedback-controlled.
Next, the configuration of the variable valve timing mechanism 113 will be described with reference to FIG.

In the present embodiment, a vane type variable valve timing mechanism is employed as the variable valve timing mechanism 113. However, the variable valve timing mechanism 113 is not limited to the vane type, and various known mechanisms such as those using an electromagnetic retarder are employed. it can.
The vane-type variable valve timing mechanism 113 is fixed to the cam sprocket 51 (timing sprocket) rotated by the crankshaft 120 via a timing chain and the end of the intake valve drive shaft 3 and is inserted into the cam sprocket 51. A rotating member 53 rotatably accommodated, a hydraulic circuit 54 for rotating the rotating member 53 relative to the cam sprocket 51, and a relative rotational position of the cam sprocket 51 and the rotating member 53 are selectively selected at predetermined positions. And a locking mechanism 60 that locks the frame.

The cam sprocket 51 includes a rotating part (not shown) having a tooth part meshed with a timing chain (or timing belt) on the outer periphery, and a housing that is disposed in front of the rotating part and rotatably accommodates the rotating member 53. 56, and a front cover and a rear cover (not shown) for closing the front and rear openings of the housing 56.
The housing 56 has a cylindrical shape with openings at the front and rear ends, and has a trapezoidal shape in cross section on the inner peripheral surface, and four partition walls 63 provided along the axial direction of the housing 56 are spaced by 90 °. It is projecting at.

The rotating member 53 is fixed to the front end portion of the intake valve drive shaft 3, and four vanes 78 a, 78 b, 78 c, 78 d are provided on the outer peripheral surface of the annular base 77 at 90 ° intervals.
Each of the first to fourth vanes 78a to 78d has a substantially inverted trapezoidal cross section, and is disposed in a recess between the partition walls 63. The recesses are separated from each other in the rotational direction, and the vanes 78a to 78d. An advance side hydraulic chamber 82 and a retard side hydraulic chamber 83 are formed between both sides and both side surfaces of each partition wall 63.

The lock mechanism 60 is configured such that the lock pin 84 engages with an engagement hole (not shown) at the rotation position (reference operation state) on the maximum retard angle side of the rotation member 53.
The hydraulic circuit 54 includes two systems, a first hydraulic passage 91 that supplies and discharges hydraulic pressure to the advance side hydraulic chamber 82 and a second hydraulic passage 92 that supplies and discharges hydraulic pressure to the retard side hydraulic chamber 83. These hydraulic passages 91 and 92 are connected to a supply passage 93 and drain passages 94a and 94b through passage switching electromagnetic switching valves 95, respectively.

The supply passage 93 is provided with an engine-driven oil pump 97 that pumps oil in the oil pan 96, while the downstream ends of the drain passages 94 a and 94 b communicate with the oil pan 96.
The first hydraulic passage 91 is connected to four branch passages 91 d that are formed substantially radially in the base 77 of the rotating member 53 and communicate with the advance-side hydraulic chambers 82. It is connected to four oil holes 92 d that open to the retard side hydraulic chamber 83.

The electromagnetic switching valve 95 is configured such that an internal spool valve body relatively switches and controls the hydraulic passages 91 and 92, the supply passage 93, and the drain passages 94a and 94b.
The engine control module 114 controls the energization amount for the electromagnetic actuator 99 that drives the electromagnetic switching valve 95 based on a duty control signal.
For example, when a control signal (OFF signal) with a duty ratio of 0% is output to the electromagnetic actuator 99, the hydraulic oil pressure-fed from the oil pump 47 is supplied to the retard-side hydraulic chamber 83 through the second hydraulic passage 92. At the same time, the hydraulic oil in the advance side hydraulic chamber 82 is discharged from the first drain passage 94 a into the oil pan 96 through the first hydraulic passage 91.

Therefore, the internal pressure of the retard side hydraulic chamber 83 is high and the internal pressure of the advance side hydraulic chamber 82 is low, and the rotating member 53 rotates to the maximum retard side via the vanes 78a to 78b. The opening period (opening timing and closing timing) of the intake valve 105 is delayed.
On the other hand, when a control signal (ON signal) with a duty ratio of 100% is output to the electromagnetic actuator 99, the hydraulic oil is supplied into the advance side hydraulic chamber 82 through the first hydraulic passage 91 and the retard side hydraulic pressure is supplied. The hydraulic oil in the chamber 83 is discharged to the oil pan 96 through the second hydraulic passage 92 and the second drain passage 94b, and the retard side hydraulic chamber 83 becomes low pressure.

For this reason, the rotating member 53 rotates to the maximum advance side via the vanes 78a to 78d, and thereby the opening period (opening timing and closing timing) of the intake valve 105 is advanced.
Next, the control (intake air amount control) of the electronic control throttle device 104, the variable lift mechanism 112 and the variable valve timing mechanism 113 by the engine control module 114 will be described in detail.

FIG. 5 shows calculation processing of the control target value (target valve lift amount) TGVEL of the variable lift mechanism 112 and the control target value (target advance amount) TGVTC of the variable valve timing mechanism 113 by the engine control module 114. It is a block diagram.
The engine control module 114 feedback-controls the variable lift mechanism 112 based on the control target value (target lift amount) TGVEL, and feeds back the variable valve timing mechanism 113 based on the control target value (target advance amount) TGVTC. Control (control means).

In FIG. 5, the engine rotational speed NE and the target volume flow ratio TQH0ST (target intake air amount) are input to the TGVEL calculator 301 and the TGVTC calculator 302, respectively.
The engine speed NE is a value calculated based on a detection signal from the crank angle sensor 117.
Further, the target volume flow ratio TQH0ST is calculated by dividing the required air amount Q obtained based on the accelerator opening APO and the engine rotational speed NE by the engine rotational speed NE and the effective exhaust amount (total cylinder volume) VOL #. (TQH0ST = Q / (Ne · VOL #)).

The TGVEL calculation unit 301 calculates a control target value TGVEL that increases the maximum valve lift amount of the intake valve 105 as the target volume flow rate ratio TQH0ST is larger and the engine rotational speed NE is higher.
The TGVTC calculator 302 calculates the control target value TGVTC so that the center phase of the valve operating angle of the intake valve 105 is retarded as the target volume flow ratio TQH0ST is larger and the engine speed NE is higher.

FIG. 6 is a block diagram showing a calculation process of the target throttle opening degree TGTVO by the engine control module 114.
In FIG. 6, the first converter 401 converts the target volume flow rate ratio TQH0ST into a state quantity AANV0 using a conversion table as shown in the figure.
The state quantity AANV0 is data represented by AANV0 = At / (Ne · VOL #), where the throttle valve opening area is At, the engine speed is NE, and the displacement (cylinder volume) is VOL #. .

Next, in the first multiplier 402 and the second multiplier 403, the state quantity AANV0 is multiplied by the engine speed NE and the exhaust amount VOL #, respectively, so that the state quantity AANV0 is converted into the basic throttle opening area TVOAA0. Is done.
The basic throttle opening area TVOAA0 is a throttle opening area required when the lift characteristic (valve lift / valve timing) of the intake valve 105 is the standard lift characteristic.

The third multiplication unit 404 multiplies the basic throttle opening area TV0AA0 by the correction value KAVEL to perform correction according to the actual lift characteristic of the intake valve 105.
The correction value KAVEL is set in order to ensure a constant amount of air even if the operating characteristic of the intake valve 105 changes, and is specifically calculated as follows.
First, in the reference pressure ratio calculation unit 410, the ratio (Pm0 / Pa) between the target manifold pressure Pm0 and the atmospheric pressure Pa when the lift characteristic of the intake valve 105 is the reference characteristic is set as the target volume flow ratio TQH0ST and the engine. Obtained based on the rotational speed NE.

Then, in the KPA0 calculation unit 411, based on the pressure ratio (Pm0 / Pa), the table TBLKPA0 shown in the figure is searched to calculate the coefficient KPA0.
On the other hand, the target pressure ratio setting unit 412 sets the target pressure ratio (Pm1 / Pa) when the variable lift mechanism 112 is controlled to the control target value TGVEL based on the target volume flow ratio TQH0ST and the engine speed NE. To do.

Then, the KPA1 calculation unit 413 searches the table TBLKPA1 shown in the figure based on the pressure ratio (Pm1 / Pa) to calculate the coefficient KPA1.
The division unit 414 divides the KPA 0 by KPA 1 to calculate a correction value KAVEL (KAVEL = KPA 0 / KPA 1), and outputs this to the third multiplication unit 404.
The throttle opening area TVOAA 0 corrected with the correction value KAVEL in the third multiplier 404 is output to the second converter 405.

The second conversion unit 405 converts the throttle opening area TVOAA0 into the target throttle opening degree TGTVO of the throttle valve 103b using a conversion table as shown in the figure and outputs it.
The engine control module 114 feedback-controls the electronic control throttle device 104 based on the target throttle opening degree TGTVO (control means).

Here, if there is dirt on the intake valve 105 / throttle valve 103b, lift characteristics of the intake valve 105 (maximum valve lift amount and central phase of the operating angle), output variations of sensors for detecting the throttle opening, Even if the target values TGVEL, TGVTC, and TGTVO are controlled, the required air amount cannot be obtained.
Therefore, the engine control module 114 detects an intake air amount control error due to the lift characteristic of the intake valve 105 and an intake air amount control error due to the opening of the throttle valve 103b, and based on the detection result, the intake valve control error is detected. 105 has a function of learning a correction value for correcting the lift characteristic control 105 and the opening degree control of the throttle valve 103b, and the learning correction function will be described below.

The flowchart of FIG. 7 shows a first embodiment of the learning correction function.
First, in step S501, learning permission conditions are detected.
Specifically, the diagnostic results of the electronically controlled throttle device 104, the variable lift mechanism 112, and the variable valve timing mechanism 113 are read, whether the internal combustion engine 101 is in a steady operation state, and whether there is no change in auxiliary load. Whether or not the internal combustion engine 101 is in a fully warmed state is detected.

In step S502, it is determined whether a learning permission condition is satisfied.
In this embodiment, the electronically controlled throttle device 104, the variable lift mechanism 112, and the variable valve timing mechanism 113 are all normal, the internal combustion engine 101 is in a steady operation state, and there is no change in auxiliary load. When the engine 101 is in a fully warmed state, it is determined that the learning permission condition is satisfied.

In addition, since it is sufficient that the learning described later is performed once or several times during one trip from when the internal combustion engine 101 is started to when it is stopped, the learning has already been performed a predetermined number of times. It can be determined that the learning permission condition is not satisfied.
If the learning permission condition is not satisfied, the process proceeds to step S503, and the electronic control throttle device 104, the variable lift mechanism 112, and the variable valve timing mechanism 113 are normally controlled based on the target values TGVEL, TGVTC, and TGTVO. .

On the other hand, if the learning permission condition is satisfied, the process proceeds to step S504, where the intake pressure (boost) PB between the throttle valve 103b and the intake valve 105 detected by the intake pressure sensor 136 is a predetermined pressure (for example, -358.5 mmHg) or more.
The predetermined pressure is a threshold value for determining whether or not the flow velocity of the intake air passing through the throttle valve 103b is substantially sonic. If the intake pressure PB is less than the predetermined pressure, the predetermined pressure passes through the throttle valve 103b. It is estimated that the flow velocity of the intake air is substantially sonic. Conversely, when the intake pressure PB is equal to or higher than the predetermined pressure, it is estimated that the flow velocity of the intake air passing through the throttle valve 103b is non-sonic.

The predetermined pressure can be variably set based on the atmospheric pressure, and further, the intake passing through the throttle valve 103b based on the ratio of the atmospheric pressure and the intake pressure PB (the pressure before and after the throttle). It is possible to determine whether or not the air flow rate is approximately the sonic speed.
When it is estimated that the intake pressure PB is less than the predetermined pressure and the flow velocity of the intake air passing through the throttle valve 103b is substantially sonic, the process proceeds to step S505.

In step S505, an error in intake air amount control due to the opening (opening area) of the throttle valve 103b is detected (first learning means).
Under the condition that the flow rate of the intake air passing through the throttle valve 103b is substantially sonic, the intake air amount of the internal combustion engine 101 is determined by the opening area of the throttle valve 103b, and the intake air amount is affected by the lift characteristics of the intake valve 105. Therefore, the intake air amount control error due to the throttle opening can be learned with high accuracy.

Therefore, in step S505, the intake air amount (reference value) estimated from the throttle opening TVO at that time is compared with the actual intake air amount detected by the airflow sensor 115, and the throttle is determined based on the deviation. A correction value for opening control is set, and the throttle opening is controlled so that the required air amount can be obtained by correction using the correction value.
That is, if there is a difference between the intake air amount (reference value) estimated from the throttle opening TVO and the actual intake air amount detected by the air flow sensor 115, the dirt of the throttle valve 103b or the throttle sensor 118 Due to variations and the like, the actual opening area of the throttle valve 103b is not a value corresponding to the target opening degree TGTVO, so that an intake air amount corresponding to the target opening degree (target opening area) is actually obtained. Therefore, even if the control is performed as it is based on the target opening degree TGTVO, the target air amount cannot be obtained.

Accordingly, the deviation between the estimated intake air amount (reference value) and the actual intake air amount is eliminated, and the target air amount is obtained in a systematic manner by controlling the throttle opening. Learning is performed according to the flowchart of FIG.
First, in step S601, the deviation between the intake air amount (design value) estimated from the target opening TGTVO and the actual intake air amount detected by the airflow sensor 115 is calculated as the actual air amount variation (Q variation). (Actual air amount variation = Design intake air amount-Actual intake air amount)

A table for storing the intake air amount as the design value (reference value) in advance corresponding to the throttle opening TVO is provided (see FIG. 9), and the design value (reference value) corresponding to the target opening TGTVO at that time From the table, the actual intake air amount detected by the air flow sensor 115 is subtracted from the search result, and the result is set to the actual air amount variation.
The design value can be corrected based on altitude (atmospheric pressure) and atmospheric temperature.

In step S602, it is determined whether or not the absolute value of the actual air amount variation exceeds a preliminarily stored allowable value.
If the absolute value of the actual air amount variation is less than the allowable value and there is a deviation between the design value (reference value) and the actual value, but the deviation is sufficiently small, update the throttle control correction value. Instead, this routine is terminated.

This prevents the correction value from hunting and the correction control from becoming unstable.
On the other hand, if the absolute value of the actual air amount variation exceeds the allowable value, the process proceeds to step S603 and subsequent steps to correct the correction value so that the actual air amount variation is within the allowable value.
In step S603, the actual air amount variation is multiplied by a previously stored gain G1, and the result is used as the TVO correction value.

In step S604, the TVO correction value is added to the previous TVO learning correction value to update and store the TVO learning correction value.
In step S605, a result obtained by subtracting the TVO learning correction value updated and stored from the detected angle of the throttle sensor 118 is set as a TVO control actual angle, and the electronic control throttle is calculated based on a comparison between the TVO control actual angle and the target angle TGTVO. The device 104 is feedback-controlled (correction means).

For example, if the opening area with respect to the opening decreases due to the dirt of the throttle valve 103b, the actual air amount variation is calculated as a positive value, and as a result, the detected value of the throttle opening is corrected negatively. The degree of opening is controlled to be higher than when the degree detection value is not corrected.
Therefore, the decrease in the throttle opening area due to the dirt is offset by correcting the throttle opening to a greater extent, and it is possible to prevent the intake air amount from becoming smaller than the target due to the dirt. The intake air amount can be controlled with high accuracy by the opening.

  In addition, the update of the TVO learning correction value is a design value obtained in a state where the flow velocity of the intake air passing through the throttle valve 103b is approximately sonic and the intake air amount is not affected by the lift characteristics of the intake valve 105. Since it is performed based on the deviation between the (reference value) and the actual value, the intake air amount control error due to the opening of the throttle valve 103b can be obtained with high accuracy without being affected by the lift characteristics of the intake valve 105. it can.

In the above description, the detection angle of the throttle sensor 118 is corrected by the correction value set based on the actual air amount variation. However, the actual intake air amount is set to the design value by correcting the target opening degree TGTVO. (Reference value).
On the other hand, if it is determined in step S504 that the intake pressure PB is equal to or higher than the predetermined pressure, the flow rate of the intake air passing through the throttle valve 103b is non-sonic, and in this case, the intake air amount is the intake air amount. It changes under the influence of the lift characteristic of the valve 105 (maximum valve lift amount / center phase of the operating angle).

Accordingly, the error in the control of the intake air amount due to the opening of the throttle valve 103b is not in a state in which the error can be learned with high accuracy. A control error is detected (second learning means).
First, in step S506, the maximum valve lift amount that is variable by the variable lift mechanism 112 is forcibly controlled to the learning lift amount.

Specifically, the target valve lift amount TGVEL is controlled to the learning lift amount by switching from the value set according to the block diagram of FIG. 5 to the learning lift amount.
In order to accurately learn the error in the intake air amount control due to the maximum valve lift amount (opening area of the intake valve 105), it is preferable that the flow rate of the intake air passing through the intake valve 105 is substantially sonic. As the lift amount for learning, for example, the minimum value of the variable range of the maximum valve lift amount (the angular position where the rotation of the control shaft 13 is limited by the stopper), or the low lift of the variable range of the maximum valve lift amount. A predetermined lift amount set in the area is used.

If the flow velocity of the intake air passing through the intake valve 105 is substantially sonic, the closing timing (valve timing) of the intake valve 105 does not greatly affect the intake air amount, and the maximum valve lift amount (opening area) of the intake valve 105 is reduced. ) Determines the intake air amount, so that the error in the intake air amount control by the maximum valve lift amount can be learned with high accuracy.
When the maximum valve lift amount is forcibly reduced in step S506, it is determined whether or not the predetermined low load region including idle is given as a permission condition. Allow switching to quantity.

When the maximum valve lift is forcibly reduced for learning during idle operation, idle rotation feedback control for matching the idle rotation speed to the target rotation speed is performed by adjusting the throttle opening, Prevents fluctuations in rotation due to a decrease in the maximum valve lift.
If the flow rate of the intake air passing through the intake valve 105 cannot be made substantially sonic due to the change to the learning lift amount in step S506, the center of the operating angle that is made variable by the variable valve timing mechanism 113. The phase is forcibly moved to the most retarded angle position to avoid the occurrence of variations in the actual intake air amount due to the difference in the center phase so that the learning accuracy is ensured.

In step S507, it is determined whether or not the maximum valve lift amount of the intake valve 105 has converged to the learning lift amount.
When the maximum valve lift amount of the intake valve 105 actually converges to the learning lift amount, the process proceeds to step S508 to detect an intake air amount control error due to the maximum valve lift amount.

Details of the learning in step S508 are shown in the flowchart of FIG.
In the flowchart of FIG. 10, in step S701, the difference between the intake air amount (design value) estimated from the target lift amount TGVEL and the like and the actual intake air amount detected by the air flow sensor 115 is calculated as the actual air amount variation ( Q variation).
As shown in FIG. 11, the intake air amount as the design value (reference value) includes a target lift amount (target angle of the control shaft 13) TGVEL, a target advance amount TGVTC, an engine speed NE, and an intake pressure PB (throttle). Calculated based on (opening degree).

In the calculation process of the design value (reference value) shown in FIG. 11, even if the flow velocity of the intake air passing through the intake valve 105 is not substantially sonic, the intake air amount (design value) under the operating conditions at that time is calculated. Can be sought.
Then, the actual intake air amount detected by the airflow sensor 115 is subtracted from the design value (reference value), and the result is set to the actual air amount variation.

In step S702, it is determined whether or not the absolute value of the actual air amount variation exceeds a preliminarily stored allowable value.
If the absolute value of the actual air amount variation is less than the allowable value and there is a deviation between the design value (reference value) and the actual value, but the deviation is sufficiently small, the correction value in the maximum valve lift amount control This routine is terminated without updating.

This prevents a learning correction value, which will be described later, from hunting and the correction control from becoming unstable.
On the other hand, if the absolute value of the actual air amount variation exceeds the allowable value, step S703 is performed to correct the correction value in the maximum valve lift amount control so that the actual air amount variation is within the allowable value. Proceed to the following.

In step S703, the actual air amount variation is multiplied by a previously stored gain G2, and the result is used as a VEL correction value.
Next, in step S704, the VEL correction value is added to the previous VEL learning correction value, and the VEL learning correction value is updated and stored.
In step S705, the result of subtracting the VEL learning correction value from the detected angle of the angle sensor 133 is set as the VEL control actual angle, and the variable lift mechanism 112 performs feedback based on the comparison between the VEL control actual angle and the target angle TGVEL. It is controlled (correction means).

It is assumed that the increasing direction of the angle of the control shaft 13 is the increasing direction of the maximum valve lift amount.
For example, when the actual valve opening area decreases with respect to the target valve lift amount due to variations in the intake valve 105 and the variable lift mechanism 112 or deterioration with time, the actual air amount variation is calculated as a positive value, and as a result, the control shaft 13 The detected angle value is negatively corrected, and the maximum valve lift amount is corrected to a larger value by controlling the angle of the control shaft 13 to be larger than when the detected angle value is not corrected. Will be.

Therefore, even if the opening area of the intake valve 105 varies due to variations or deterioration of the intake valve 105 / variable lift mechanism 112, the maximum valve lift amount (opening area) of the intake valve 105 is reduced to the design value (reference value). The air amount can be controlled to a value that can be obtained, and the control accuracy of the intake air amount by controlling the maximum valve lift amount can be improved.
Instead of correcting the detection angle of the angle sensor 133 with the VEL learning correction value, the actual intake air amount is set to the design value (reference value) by correcting the target angle (target valve lift amount) of the control shaft 13. Can be approached.

In step S509, the error in the intake air amount control based on the opening degree of the throttle valve 103b (update of the TVO learning correction value) and the intake air amount control error due to the maximum valve lift amount (lift characteristic) of the intake valve 105 are described. It is determined whether or not learning (update of the VEL learning correction value) has been experienced.
The learning experience can be an experience during one trip from when the ignition switch is turned on to when it is turned off, and can also be an experience during a predetermined travel time and travel distance. In addition to being able to determine that the TVO learning correction value / VEL learning correction value has been updated even once, it can be determined that the TVO learning correction value / VEL learning correction value has been experienced. .

If both of the learnings are experienced, the process proceeds to step S510 (air-fuel ratio learning permission means) to permit (execute) the air-fuel ratio learning. If both learnings are not experienced, step S510 is performed. By bypassing S510 and ending this routine, air-fuel ratio learning is prohibited.
In the air-fuel ratio learning, an air-fuel ratio correction value for correcting the fuel injection amount so as to bring the actual air-fuel ratio closer to the target air-fuel ratio is stored in an updatable manner, and the actual air-fuel ratio detected by the air-fuel ratio sensor 137 is stored. The air-fuel ratio correction value is updated based on the engine air-fuel ratio correction value, and the air-fuel ratio correction value is set individually for each of a plurality of operation regions divided by, for example, the engine operating state (engine load / engine speed). . When the air-fuel ratio learning is not permitted, the update of the air-fuel ratio correction value is prohibited.

  The air-fuel ratio learning is performed in a state in which learning of the intake air amount control error due to the opening of the throttle valve 103b and the intake air amount control error due to the maximum valve lift amount (lift characteristic) of the intake valve 105 is not experienced. If this is done, then the intake air amount learning is performed, thereby causing a difference between the operating condition in which the air-fuel ratio learning is performed and the operating condition after the intake air amount learning, and the air-fuel ratio controllability is reduced.

Therefore, the air-fuel ratio learning is performed after learning the intake air amount so that the air-fuel ratio controllability can be prevented from being deteriorated.
The flowchart of FIG. 12 shows the air-fuel ratio learning process. First, in step S1301, whether or not the internal combustion engine 101 is in a steady operation state is determined from a change in the throttle opening or the like.

If it is not in a steady operation state (when it is in an acceleration / deceleration state), this routine is terminated as it is without performing air-fuel ratio learning described later. If it is in a steady operation state, the process proceeds to step S1302.
In step S1302, it is determined whether an air-fuel ratio learning permission condition is satisfied.
Specifically, when the intake air amount learning is experienced and the blow-by gas or the canister purge is stopped, it is determined that the permission condition for the air-fuel ratio learning is satisfied.

The permission conditions other than the fact that the intake air amount learning is experienced are not limited to the above-mentioned conditions. For example, the air-fuel ratio sensor 137 is activated, a predetermined engine load / rotation speed region is set. It may be determined that it is.
In addition, the permission condition for the intake air amount learning and the permission condition for the air-fuel ratio learning can be made the same.

If it is determined in step S1302 that the air-fuel ratio learning permission condition is not satisfied, this routine is terminated without performing the air-fuel ratio learning described later, and the air-fuel ratio learning permission condition is satisfied. If so, the process advances to step S1303.
In step S1303, the air-fuel ratio feedback correction value AFALP at that time is set to the latest air-fuel ratio learning value AFGAKU, and the air-fuel ratio feedback correction value AFALP is reset to the reference value 1.0.

The air / fuel ratio feedback correction value AFALP is calculated by a proportional / integral / differential operation based on the deviation between the target air / fuel ratio and the actual air / fuel ratio detected by the air / fuel ratio sensor 137.
In step S1304, the air-fuel ratio learning value AFGKU is updated and stored in the air-fuel ratio learning map.
As shown in FIG. 13, the air-fuel ratio learning map is divided into a plurality of operation regions (for example, 8 × 8 64 regions) divided into a plurality of basic fuel injection amounts TP representing engine load and engine speed NE. The air-fuel ratio learning value AFGKU is stored in a rewritable manner, and in step S1304, the current engine load (basic fuel injection amount TP) and engine speed NE are selected among the plurality of operation areas. On the other hand, the air-fuel ratio learned value AFGAKU obtained in step S1303 is updated and stored.

The flowchart in FIG. 14 shows a process for setting the fuel injection amount. In step S1401, the basic fuel injection amount TP is calculated.
The basic fuel injection amount TP is based on the engine rotational speed Ne, the intake air amount Qa detected by the air flow sensor 115, and a coefficient K set in advance from the flow rate characteristic of the fuel injection valve 131. TP = Qa / NE * Calculated as K.

The basic fuel injection amount TP is calculated as a fuel amount required to form a stoichiometric air-fuel mixture.
In step S1402, the air-fuel ratio learning value AFGKU stored in the operation region corresponding to the basic fuel injection amount TP and the engine speed NE at that time is read from the air-fuel ratio learning map.

In step S1403, as described above, the air-fuel ratio feedback correction value AFALP calculated by the proportional / integral / differential operation based on the deviation between the target air-fuel ratio and the actual air-fuel ratio detected by the air-fuel ratio sensor 137 is read.
In step S1404, the target equivalent ratio (target air-fuel ratio) at that time is read.
An air-fuel ratio map in which the target equivalent ratio (target air-fuel ratio) is stored in advance is provided for each operation region divided into a plurality of basic fuel injection amounts TP representing engine load and engine rotational speed NE. The target equivalent ratio (target air-fuel ratio) in a region corresponding to the basic fuel injection amount TP and the engine speed NE at that time is read from the map.

In step S1405, the final fuel injection amount TI is calculated according to the following equation.
TI = TP × target equivalent ratio × (AFALP + AFGAKU-1) + TS
In the above equation, TS is a correction amount for the delay in opening the fuel injection valve 131, and is set based on the power supply voltage (battery voltage) of the fuel injection valve 131.
The flowchart of FIG. 15 shows a second embodiment of the intake air amount learning correction function.

In the flowchart of FIG. 15, each of steps S801 to S805 performs the same processing as steps S501 to S505 in the flowchart of FIG. 7 illustrating the first embodiment.
In step S804, it is determined that the intake pressure (boost) PB between the throttle valve 103b and the intake valve 105 detected by the intake pressure sensor 136 is equal to or higher than a predetermined pressure (for example, −358.5 mmHg). In S806, it is determined whether or not the flow rate of the intake air passing through the intake valve 105 is substantially sonic in the current operating state.

The predetermined pressure (for example, −358.5 mmHg) is set as a value at which the intake air passing through the throttle valve has a substantially sonic speed.
The determination of whether or not the speed is approximately sonic is made based on the intake pressure (boost) PB, the maximum valve lift amount, the engine speed, and the like at that time.
If the flow rate of the intake air passing through the intake valve 105 is approximately sonic, the process proceeds to step S807, where learning of the intake air amount control error based on the maximum valve lift amount (lift characteristic) of the intake valve 105 (VEL learning correction value Update) is performed according to the flowchart of FIG. 10 (second learning means).

On the other hand, if the flow velocity of the intake air passing through the intake valve 105 is non-sonic, the process proceeds to step S808, and learning of an intake air amount control error based on the center phase (lift characteristic) of the operating angle of the intake valve 105 (VTC learning correction). The value is updated) according to the flowchart of FIG. 16 (second learning means).
When the flow rate of the intake air passing through the intake valve 105 is substantially sonic, the intake air amount changes depending on the maximum valve lift amount (opening area) of the intake valve 105, and in the center phase (the intake valve 105 closing timing). Since it is not affected, the error in the intake air amount control by the maximum valve lift amount (opening area) can be learned with high accuracy.

  In addition, when the flow rate of the intake air passing through the intake valve 105 is non-sonic, the intake air amount changes due to a change in the closing timing due to a change in the center phase of the operation angle of the intake valve 105. By learning the error in the intake air amount control, it is possible to improve both the control accuracy of the intake air amount based on the opening area of the intake valve 105 and the center phase.

In the flowchart of FIG. 16, in step S901, the difference between the intake air amount (design value) estimated from the target advance value TGVTC and the like and the actual intake air amount detected by the air flow sensor 115 is determined as the actual air amount variation. Calculate as
As shown in FIG. 11, the intake air amount as the design value (reference value) includes a target lift amount (target angle of the control shaft 13) TGVEL, a target advance amount TGVTC, an engine speed NE, and an intake pressure PB ( The actual intake air amount detected by the airflow sensor 115 is subtracted from the design value (reference value) calculated based on the throttle opening), and the result is set to the actual air amount variation.

In step S902, it is determined whether or not the absolute value of the actual air amount variation exceeds an allowable value.
If the absolute value of the actual air amount variation is less than the allowable value and there is a deviation between the design value (reference value) and the actual value, but the deviation is sufficiently small, the correction value in the center phase control is updated. This routine is terminated without performing it.

This prevents a learning correction value, which will be described later, from hunting and the correction control from becoming unstable.
On the other hand, when the absolute value of the actual air amount variation exceeds the allowable value, the process proceeds to step S903 and subsequent steps so as to correct the correction value in the center phase control so that the actual air amount variation is within the allowable value. move on.

In step S903, the variation in actual air amount is multiplied by a gain G3 stored in advance, and the result is used as a VTC correction value.
Next, in step S904, the VTC learning correction value is added to the previous VTC learning correction value, and the VTC learning correction value is updated and stored.
In step S905, the result of adding the VTC learning correction value from the actual advance value detected by the sensor is taken as the VTC control actual angle, and based on the comparison between this VTC control actual angle and the target advance value TGVTC, The variable valve timing mechanism 113 is feedback-controlled.

The center phase of the operating angle is indicated by an advance amount from the most retarded position.
For example, when the actual intake air amount is smaller than the designed intake air amount and the actual air amount variation is calculated to be a positive value, the VTC control actual angle is corrected to the more advanced side, and VTC As a result of being controlled more retarded than when the detection value is not corrected with the learning correction value, the closing timing IVC of the intake valve 105 approaches the bottom dead center BDC, and the intake air amount is increased.

The actual intake air amount can be brought close to the design value (reference value) by correcting the target advance value instead of correcting the detection result of the center phase with the VTC learning correction value.
In steps S809 and S810, as in steps S509 and S510, learning of the intake air amount control error based on the opening of the throttle valve 103b (update of the TVO learning correction value), the maximum valve lift amount of the intake valve 105 ( Learning of intake air amount control error (lift characteristic) (update of VEL learning correction value), and learning of intake air amount control error (center characteristic of lift valve) operating angle (lift characteristic) (VTC learning correction value) The air-fuel ratio learning is permitted on the condition that the user has experienced renewal of

The air-fuel ratio learning process and the fuel injection amount TI calculation process using the air-fuel ratio learned value are performed in the same manner as described with reference to FIGS. 12 to 14 in the first embodiment.
The flowchart of FIG. 17 shows a third embodiment of the intake air amount learning correction function.
In the third embodiment, as compared with the second embodiment shown in the flowchart of FIG. 15, an intake valve is used as a condition for learning an error in intake air amount control based on the center phase (lift characteristic) of the operating angle of the intake valve 105. In addition to the fact that the flow velocity of the intake air passing through 105 is non-sonic, it is determined that the learning of the error in the intake air amount control by the maximum valve lift amount (lift characteristic) of the intake valve 105 has been experienced. It is.

That is, Steps S1001 to S1007 perform the same processing as Steps S801 to S807. If it is determined in Step S1006 that the flow velocity of the intake air passing through the intake valve 105 is non-sonic, the process proceeds to Step S1008. move on.
In step S1008, it is determined whether or not learning of an intake air amount control error based on the maximum valve lift amount (lift characteristic) of the intake valve 105 has been experienced.

As shown in FIG. 18, the characteristics of the intake valve passing air amount with respect to the opening area of the intake valve show different characteristics in the three regions.
First, in the region A having a small opening area where the flow velocity of the intake air passing through the intake valve 105 is substantially sonic, the intake air amount varies depending on the maximum valve lift amount (opening area) of the intake valve 105.

On the other hand, in the region C that is near the maximum value of the opening area of the intake valve 105, the amount of intake air changes by the change in the closing timing IVC of the intake valve 105 rather than the opening area, and the region B that is sandwiched between the region A and the region C In this case, the intake air amount is changed by being influenced by both the opening area of the intake valve 105 and the closing timing IVC.
Here, in both regions B and C, since the flow velocity of the intake air passing through the intake valve 105 is a non-sonic condition, it is determined in step S1006 that the flow velocity of the intake air passing through the intake valve 105 is a non-sonic condition. If it is determined that there is an error learning of the intake air amount control based on the center phase in step S1009 as it is, there is a possibility of learning in the region B.

However, in the region B, as described above, since the intake air amount changes depending on both the opening area of the intake valve 105 and the closing timing IVC, the intake by the maximum valve lift amount (opening area) of the intake valve 105 is performed. When the control error of the air amount is not learned, the control error of the maximum valve lift is erroneously learned as the control error of the center phase.
On the other hand, if the control error of the intake air amount by the maximum valve lift amount (opening area) has already been learned, the error between the design intake air amount and the actual value in the region B is the control error of the center phase (closing timing). Therefore, mislearning can be avoided.

  Therefore, in the third embodiment, in step S1006, it is determined that the flow velocity of the intake air passing through the intake valve 105 is non-sonic, and in step S1008, the intake air amount based on the maximum valve lift amount (opening area) is determined. When it is determined that the control error has been learned, the process proceeds to step S1009 to learn the intake air amount control error based on the center phase (closing timing).

On the other hand, when the control error of the intake air amount due to the maximum valve lift amount (opening area) has not been learned, the center phase (closing timing) even if the flow velocity of the intake air passing through the intake valve 105 is non-sonic. The error learning of the intake air amount control by is prohibited.
As a result, the intake air amount control error due to the maximum valve lift amount (opening area) and the intake air amount control error due to the center phase (closing timing) can both be learned with high accuracy.

  In steps S1010 and S1011, the learning of the intake air amount control error based on the opening of the throttle valve 103b (update of the TVO learning correction value) and the maximum valve lift amount of the intake valve 105 (update of the throttle valve 103b) are performed as in steps S509 and S510. Learning of intake air amount control error (lift characteristic) (update of VEL learning correction value), and learning of intake air amount control error (center characteristic of lift valve) operating angle (lift characteristic) (VTC learning correction value) The air-fuel ratio learning is permitted on the condition that the user has experienced renewal of

The air-fuel ratio learning process and the fuel injection amount TI calculation process using the air-fuel ratio learned value are performed in the same manner as described with reference to FIGS. 12 to 14 in the first embodiment.
FIG. 19 shows a fourth embodiment of the learning correction function for the intake air amount.
In the flowchart of FIG. 19, steps S1101 to S1105 perform the same processes as steps S501 to S505 in the flowchart of FIG. 7 showing the first embodiment.

  In step S1104, it is determined that the intake pressure (boost) PB between the throttle valve 103b and the intake valve 105 detected by the intake pressure sensor 136 is equal to or higher than a predetermined pressure (for example, −358.5 mmHg) (non-sonic speed). In step S1106, it is determined whether or not learning of the intake air amount control error (update of the VEL learning correction value) using the maximum valve lift amount of the intake valve 105 has been experienced.

  If it is determined in step S1106 that it has not been experienced, the process proceeds to steps S1107 and S1108 to learn the error in the intake air amount control based on the maximum valve lift amount, and it is determined that it has been experienced in step S1106. If YES in step S1109, the flow advances to steps S1109 and S1110 to learn an error in intake air amount control due to the center phase (closing timing).

As explained in the third embodiment, when learning the intake air amount control error due to the center phase (closed timing), the error is learned including the intake air amount control error due to the maximum valve lift amount. This is to prevent this from happening.
In steps S1107 and S1108, as in steps S506 to S508 in the first embodiment, the maximum valve lift amount is switched to a learning value, and an error in intake air amount control based on the maximum valve lift amount is learned. Let

That is, when the maximum valve lift amount is switched to the learning lift amount and converges to the learning lift amount, the design value (reference value) of the intake air amount estimated from the operating conditions at that time and the actual value detected by the sensor Based on the deviation from the intake air amount, the VEL learning correction value is updated, and the update result is stored.
On the other hand, in step S1109, the center phase of the operating angle of the intake valve 105 is forcibly switched to the learning center phase.

The learning center phase is set to the most retarded position in the variable range by the variable valve timing mechanism 113.
As described above, when the flow velocity of the intake air passing through the intake valve 105 is substantially sonic (region A), the intake air amount is determined by the maximum valve lift amount of the intake valve 105, and the valve timing (closing timing) Since it is not affected, it is not possible to learn an intake air amount control error due to valve timing (closing timing).

Therefore, when the flow velocity of the intake air passing through the intake valve 105 becomes substantially sonic, the maximum valve lift is forcibly increased so that the flow velocity of the intake air passing through the intake valve 105 becomes non-sonic.
When the valve timing converges to the learning center phase (most retarded angle position), the process proceeds to step S1110 to learn the intake air amount control error based on the center phase.

Specifically, the VTC learning correction value is updated based on the deviation between the design value (reference value) of the intake air amount and the actual intake air amount in accordance with the flowchart of FIG. By correcting the phase detection value, the intake air amount of the design value (reference value) corresponding to the center phase is obtained.
In steps S1111 and S1112, similar to steps S509 and S510, learning of the intake air amount control error (update of the TVO learning correction value) based on the opening of the throttle valve 103b, and the maximum valve lift amount of the intake valve 105 ( Learning of intake air amount control error (lift characteristic) (update of VEL learning correction value), and learning of intake air amount control error (center characteristic of lift valve) operating angle (lift characteristic) (VTC learning correction value) The air-fuel ratio learning is permitted on the condition that the user has experienced renewal of

The air-fuel ratio learning process and the fuel injection amount TI calculation process using the air-fuel ratio learned value are performed in the same manner as described with reference to FIGS. 12 to 14 in the first embodiment.
Also in the fourth embodiment, it is possible to prevent the intake air amount control error due to the maximum valve lift amount from being erroneously learned as the intake air amount control error due to the center phase, and the learning maximum valve lift amount. Since learning is performed by switching to the center phase, it is not necessary to wait for a condition for learning, and learning can proceed promptly.

  Incidentally, in the above embodiment, the exhaust valve 107 is driven to open and close while maintaining a certain maximum valve lift amount, valve operating angle and valve timing. However, as shown in FIG. In the engine 101 provided with the variable valve timing mechanism 138 that changes the rotational phase of the side camshaft 110, the intake air amount learning can be performed in the same manner as in the above embodiments.

  As shown in FIG. 21, the variable valve timing mechanism 138 is fixed to a sprocket 225 that rotates in synchronization with the crankshaft 120, and a first rotating body 221 that rotates integrally with the sprocket 225 and a bolt 222a. A second rotating body 222 that is fixed to one end of the exhaust side camshaft 110 and rotates integrally with the exhaust side camshaft 110, and an inner peripheral surface of the first rotating body 221 and an outer periphery of the second rotating body 222 by a helical spline 226. A cylindrical intermediate gear 223 that meshes with the surface.

The intermediate gear 223 is connected to a drum 227 via a screw 228, and a torsion spring 229 is interposed between the drum 227 and the intermediate gear 223.
The intermediate gear 223 is urged in the retarding direction (left direction in the figure) by a torsion spring 229. When a voltage is applied to the electromagnetic retarder 224 to generate a magnetic force, the intermediate gear 223 is advanced through the drum 227 and the screw 228. It is moved in the direction (right direction in the figure).

In accordance with the axial position of the intermediate gear 223, the relative phase of the rotating bodies 221 and 222 changes, the rotational phase of the exhaust camshaft 110 with respect to the crankshaft 120 changes, and the central phase of the operating angle of the exhaust valve 107 Changes continuously.
The electromagnetic retarder 224 is driven and controlled by a control signal from the engine control module 114.

  As described above, when the central phase (opening / closing timing) of the operating angle of the exhaust valve 107 is changed by the variable valve timing mechanism 138, the intake air amount changes due to the change in charging efficiency due to the valve timing of the exhaust valve 107, etc. Therefore, in the calculation of the design intake air amount, as shown in FIG. 22, the design intake air amount can be accurately calculated by adding the center phase of the operating angle of the exhaust valve 107 to the input data.

The internal combustion engine 101 is not limited to an in-line engine, and may be an engine having a plurality of banks such as horizontally opposed and V-shaped.
Further, when the engine is a horizontally opposed engine or a V-type engine and includes a plurality of banks, and each bank includes an electronic control throttle device 104, a variable lift mechanism 112, and a variable valve timing mechanism 113, the intake air amount The control error is detected as a deviation of the actual intake air amount between banks, and the throttle opening, maximum valve lift amount, and center phase are corrected for each bank so that the intake air amount in each bank matches. Can do.

  With the above configuration, it is possible to eliminate the variation in intake air amount in each bank and prevent the occurrence of rotational fluctuations.

The system figure of the internal combustion engine for vehicles in an embodiment. The perspective view which shows the detail of the variable lift mechanism in embodiment. Sectional drawing which shows the operating angle change mechanism of the said variable lift mechanism. Sectional drawing which shows the detail of the variable valve timing mechanism in embodiment. The block diagram which shows the calculation process of the target valve lift amount and target valve timing in embodiment. The block diagram which shows the calculation process of the target throttle opening in embodiment. The flowchart which shows 1st Embodiment of intake air amount learning. The flowchart which shows the error learning of the intake air amount control by throttle opening. The diagram which shows the correlation with the throttle opening and intake air amount when the passage air of a throttle valve is a substantially sonic speed. The flowchart which shows the error learning of intake air amount control by the maximum valve lift amount of an intake valve. The block diagram which shows the calculation of the design value of intake air amount. The flowchart which shows an air fuel ratio learning process. The figure which shows the air fuel ratio learning map which memorize | stores an air fuel ratio learning value so that rewriting is possible. The flowchart which shows the calculation process of fuel injection quantity. The flowchart which shows 2nd Embodiment of intake air amount learning. The flowchart which shows the error learning of intake air amount control by the center phase of the operating angle of an intake valve. The flowchart which shows 3rd Embodiment of intake air quantity learning. The diagram which shows the correlation with the opening area of an intake valve, and the passage air amount of an intake valve. The flowchart which shows 4th Embodiment of intake air amount learning. The system figure of the internal combustion engine for vehicles provided with the variable valve timing mechanism of an exhaust valve. Sectional drawing which shows the variable valve timing mechanism of an exhaust valve. The block diagram which shows the calculation of the design value of intake air quantity in the case of providing the variable valve timing mechanism of an exhaust valve.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Intake valve drive shaft, 13 ... Control shaft, 17 ... Motor, 101 ... Internal combustion engine, 103a ... Throttle motor, 103b ... Throttle valve, 104 ... Electronically controlled throttle device, 105 ... Intake valve, 112 ... Variable lift mechanism, 113 ... Variable valve timing mechanism, 114 ... Engine control module, 115 ... Air flow sensor, 116 ... Accelerator pedal sensor, 117 ... Crank angle sensor, 120 ... Crank shaft, 132 ... Cam sensor, 133 ... Angle sensor, 135 ... Atmospheric pressure sensor, 136 ... Intake pressure sensor, 137 ... Air-fuel ratio sensor

Claims (6)

A variable valve mechanism that includes a variable lift mechanism that varies the maximum valve lift amount of the intake valve, and a variable valve timing mechanism that varies the center phase of the operating angle of the intake valve;
An intake throttle valve interposed in an intake passage upstream of the intake valve;
Control means for controlling the intake air amount of the engine by controlling the maximum valve lift amount of the intake valve, the central phase of the operating angle of the intake valve and the opening of the intake throttle valve;
First learning means for learning an error in intake air amount control based on an opening degree of the intake throttle valve when the flow velocity of the intake air passing through the intake throttle valve is approximately sonic;
When the flow rate of the intake air passing through the intake throttle valve is a non-sonic condition, the intake air amount control error due to the maximum valve lift amount of the intake valve and the center phase of the operating angle of the intake valve Second learning means for individually learning errors in intake air amount control;
Based on the learning results of the first learning means and the second learning means, the control means controls the maximum valve lift amount of the intake valve, the center phase of the operating angle of the intake valve, and the opening degree of the intake throttle valve. Correction means for correcting;
Comprising
The second learning means is
Suction passing through the intake valve in a state where the variable lift mechanism is controlled so that the maximum valve lift amount is a learning lift amount so that the flow velocity of the intake air passing through the intake valve is substantially sonic. When the flow velocity of air becomes substantially sonic, the learning lift amount is learned by learning an intake air amount control error based on the maximum valve lift amount of the intake valve based on the intake air amount at the learning lift amount. If the flow rate of the intake air passing through the intake valve does not become nearly sonic speed even if the variable lift mechanism is controlled so that the center angle of the operating angle of the intake valve is delayed by the variable valve timing mechanism. The maximum valve lift of the intake valve is moved based on the intake air amount when the center phase is the most retarded angle position and the maximum valve lift amount is the learning lift amount. A lift learning means for learning the error of the intake air amount control by the quantity,
After learning by the lift learning means, and when the flow velocity of the intake air passing through the intake valve is non-sonic, the intake air amount control error due to the center phase of the operating angle of the intake valve Valve timing learning means for learning
An intake air amount control device for an internal combustion engine , comprising:   The second learning means sets a reference value of the intake air amount at that time based on the maximum valve lift amount and the center phase of the intake valve, and calculates a deviation between the reference value and the actual intake air amount. The intake air amount control device for an internal combustion engine according to claim 1. Equipped with an exhaust side variable valve timing mechanism that makes the center phase of the exhaust valve operating angle variable,
The said 2nd learning means sets the reference value of the intake air amount at that time based on the center phase of the operating angle of the said exhaust valve with the maximum valve lift amount and center phase of the said intake valve. Item 3. An intake air amount control device for an internal combustion engine according to Item 2. The first learning means has a reference value of the intake air amount set from the opening of the intake throttle valve and the actual intake at that time under the condition that the flow velocity of the intake air passing through the intake throttle valve is substantially sonic. 4. The intake air amount control device for an internal combustion engine according to claim 1, wherein a deviation from the air amount is calculated . Based on the intake pressure between the intake throttle valve and the intake valve, the first and second learning means determine whether or not the flow velocity of the intake air passing through the intake throttle valve is a substantially sonic speed. The intake air amount control device for an internal combustion engine according to any one of claims 1 to 4, characterized in that Provided is an air-fuel ratio learning permission means for permitting an update of a learning correction value for correcting the air-fuel ratio of the internal combustion engine to a target air-fuel ratio on the condition that learning by the first and second learning means is experienced. The intake air amount control device for an internal combustion engine according to any one of claims 1 to 5, wherein

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