JPH109012A - Electronic throttle control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To automatically change a throttle opening control characteristic so as to satisfy a driver's request for acceleration (how to depress an accelerator pedal). SOLUTION: The distribution of the maximum accelerator speed plotted on a lognormal probability paper is approximated by a straight line bent at one inflection point, and a region where the maximum accelerator speed is smaller than the inflection point indicates that the driver can accelerate gently. The area you are requesting,
A region where the maximum accelerator speed is higher than the inflection point is a region where the driver requests an acceleration response. Therefore, the inflection point of this distribution is learned as a reference value, the detected accelerator speed is compared with the reference value, and the control characteristic of the throttle opening is changed according to the comparison result. As a result, the throttle opening control characteristics can be automatically changed so as to satisfy the driver's request for acceleration (how to depress the accelerator pedal), and stable throttle control that is not affected by manufacturing variations of the vehicle can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic throttle control device for an internal combustion engine in which a throttle valve is driven by a motor or the like in response to an accelerator operation to electrically control a throttle opening.

[0002]

2. Description of the Related Art A conventional general electronic throttle control device detects an amount of depression of an accelerator pedal by an accelerator sensor, sets a target throttle opening in accordance with the detected value, and drives a throttle valve by a motor or the like. Then, the throttle opening is made to match the target throttle opening with good responsiveness to the accelerator operation. In this system, when the driver depresses the accelerator pedal suddenly for rapid acceleration, the driver immediately follows the accelerator pedal and suddenly increases the throttle opening, causing a torque shock and unpleasant vehicle vibration. It has been known.

To solve this problem, Japanese Patent Application Laid-Open No. 61-17 / 1986
As disclosed in Japanese Patent No. 1846, an accelerator speed (speed at which an accelerator pedal is depressed) is compared with a preset reference value to determine whether or not the vehicle is suddenly accelerated. There is one in which the control characteristic of the throttle opening is corrected so as to reduce the change. Further, as disclosed in Japanese Patent Application Laid-Open No. 61-25937, in order to prevent vehicle vibration that occurs when the vehicle suddenly accelerates from near the throttle fully closed, when the vehicle is accelerated from near the throttle fully closed, the accelerator operation is not performed. In some cases, a target throttle opening is set with a predetermined delay, and the throttle opening is changed with a delay with respect to an accelerator operation.

[0004]

By the way, when the driver wants to accelerate rapidly and depresses the accelerator pedal greatly, it is necessary to reduce or delay the change in the throttle opening degree.
Acceleration is slowed down and must be kept to a minimum. However, in any of the systems disclosed in the above publications, since the criterion for correcting the control characteristic of the throttle opening during acceleration is fixed, it is not possible to cope with the characteristic deviation due to manufacturing variations of the vehicle. For this reason, there is a possibility that the acceleration may be slowed in a driving region where vehicle vibration does not occur so much against the driver's request.
Also, if the manufacturing variability of the vehicle is to be reflected in the above-described criteria for the throttle control characteristic correction, it is necessary to require a huge number of conforming man-hours, and it is necessary to add a number of condition determination steps and a number of maps to the control program. , That much, R
It is necessary to increase the OM capacity, which causes an increase in cost.

[0005] The present invention has been made in view of such circumstances, and accordingly, it is an object of the present invention to realize a stable throttle control that is not affected by manufacturing variations of a vehicle and to provide a driver with a demand for acceleration (accelerator pedal). The present invention provides an electronic throttle control device for an internal combustion engine that can automatically change the control characteristic of the throttle opening degree so as to satisfy the above-mentioned steps and can reduce the number of man-hours and the ROM capacity for absorbing manufacturing variations of vehicles. It is in.

[0006]

In order to achieve the above object, in the electronic throttle control apparatus for an internal combustion engine according to the first aspect of the present invention, a distribution of a physical quantity indicating a mode of a past accelerator operation performed by a driver ( (Hereinafter referred to as "accelerator operation statistical data distribution"), and the control characteristic of the throttle opening for the accelerator operation is changed by the control characteristic changing means in accordance with the accelerator operation statistical data distribution.

The method of pressing the accelerator pedal varies depending on the driver's temperament, but the same driver tends to increase the accelerator pedal pressing amount when driving a vehicle with poor acceleration, and conversely, a vehicle with good acceleration. , There is a tendency that the depression amount of the accelerator pedal is reduced. Therefore, as in the present invention, if the distribution of the physical quantity (accelerator operation statistical data distribution) indicating the mode of the past accelerator operation performed by the driver is determined, both the manufacturing variation of the vehicle and the demand for acceleration of the driver are determined. Can be determined at the same time, and the tendency of the accelerator operation can be determined. Therefore, by changing the control characteristics of the throttle opening in accordance with the distribution of the accelerator operation statistical data, it is possible to realize a stable throttle control that is not affected by manufacturing variations of the vehicle, and to meet a demand for driver acceleration (how to depress the accelerator pedal). ), The control characteristics of the throttle opening can be automatically changed. In addition, since special processing for absorbing manufacturing variations of the vehicle is not required, the number of adaptation steps and the ROM capacity can be reduced, which is advantageous in cost.

[0008] In this case, at least one of an accelerator speed, an accelerator acceleration, and an accelerator pedal depression amount at the time of accelerator operation may be used as the physical quantity indicating the mode of the accelerator operation. The accelerator speed, the accelerator acceleration, and the accelerator depression amount are all indexes indicating the driver's request for acceleration.

Further, when it is determined whether the control characteristic of the throttle opening is to be changed by comparing a physical quantity indicating the mode of the current accelerator operation with a predetermined reference value, the reference value may be determined. May be corrected by the learning means based on the accelerator operation statistical data distribution. This also makes it possible to change the control characteristic of the throttle opening according to the distribution of the accelerator operation statistical data.

In this case, it is preferable that the reference value is learned and corrected so that the reference value matches the inflection point of the accelerator operation statistical data distribution. That is, as shown in FIG. 8, a region where the driver requests an acceleration response and a region where a gentle acceleration is requested at the inflection point of the accelerator operation statistical data distribution (accelerator speed distribution). If the learning correction is performed so that the inflection point of this distribution matches the reference value, the driver's request for acceleration can be accurately reflected in the throttle control.

According to a fifth aspect of the present invention, a physical quantity that changes in accordance with the distribution of the accelerator operation statistical data is set as a reference value, and the physical quantity indicating the current mode of accelerator operation is compared with the reference value to open the throttle. It may be determined whether or not the degree control characteristic is changed. Even in this case, the control characteristic of the throttle opening can be changed according to the accelerator operation statistical data distribution.

In this case, at least one of an inflection point, a standard deviation, and a median of an accelerator operation statistical data distribution may be used as the physical quantity for setting the reference value. The inflection point, standard deviation, and median value of the accelerator operation statistical data distribution are all indexes that indicate the characteristics of the accelerator operation statistical data distribution.

Alternatively, the physical quantity for setting the reference value may be an amount such that the cumulative frequency in the accelerator operation statistical data distribution becomes a predetermined percentage. The amount at which the cumulative frequency becomes a predetermined percentage is also an index indicating the characteristics of the accelerator operation statistical data distribution.

According to another aspect of the present invention, the control characteristic is such that when the physical quantity indicating the mode of the accelerator operation this time is equal to or less than the reference value, the drive speed of the throttle valve is made slower than in other cases. It is preferable to change. In this way, the drive speed of the throttle valve can be reduced gently in a region where the driver requires gentle acceleration, and smooth acceleration with reduced torque fluctuation can be achieved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

<< Embodiment (1) >> An embodiment (1) of the present invention will be described below with reference to FIGS. First, a schematic configuration of the entire control system of the internal combustion engine 11 will be described with reference to FIG. An air cleaner 13 is mounted on an upstream side of an intake pipe 12 of the internal combustion engine 11, an air flow meter 14 for measuring an intake air amount Ga is provided on a downstream side thereof, and a throttle valve 15 is further provided on a downstream side thereof. The rotation shaft of the throttle valve 15 has a DC
The motor 17 (throttle driving means) is connected, and the opening of the throttle valve 15 (throttle opening) is controlled by the driving force of the DC motor 17. This throttle opening is detected by the throttle sensor 18.

An intake manifold 1 for introducing the intake air passing through the throttle valve 15 to each cylinder of the internal combustion engine 11
An injector 20 is attached to the cylinder 9, and a spark plug 21 is attached to a cylinder head of each cylinder of the internal combustion engine 11.
Is attached. Crankshaft 22 of internal combustion engine 11
A crank angle sensor 24 is attached to an outer periphery of a signal rotor 23 fitted to the engine, and a pulse-shaped engine speed signal Ne output from the crank angle sensor 24 is taken into an electronic control unit (ECU) 25. The engine speed is detected from the pulse interval of the engine speed signal Ne.

On the other hand, the depression amount of the accelerator pedal 26 (accelerator opening Ap) is detected by an accelerator sensor 27, and a voltage signal corresponding to the accelerator opening Ap is taken into the electronic control unit 25 via the A / D converter 28. It is. Each voltage signal of the intake air amount Ga detected by the air flow meter 14 and the throttle opening TA detected by the throttle sensor 18 is also taken into the electronic control unit 25 via the A / D converter 28.

The electronic control unit 25 includes a CPU 2
9, a microcomputer including a ROM 30, a RAM 31, and the like. The CPU 29 executes various programs for controlling the internal combustion engine stored in the ROM 30, thereby controlling the ignition timing of the ignition plug 21 and the injector. An injection pulse given to the injector 20 via the drive circuit 45 is controlled to control a fuel injection amount. Further, the electronic control unit 25 connects (ON) the electromagnetic clutch 16 via the electromagnetic clutch drive circuit 46 when the accelerator pedal 26 is depressed from the fully closed position.
The driver 32 according to the accelerator operation amount Ap.
The DC motor 17 is controlled via the control unit and the throttle opening TA is adjusted by the driving force.

Next, the configuration of the electronic throttle system will be described with reference to FIG. The accelerator pedal 26 is connected to an accelerator lever 34 via a wire 33. The accelerator lever 34 is urged downward (in the accelerator closing direction) by accelerator return springs 35 and 36. When the accelerator pedal 26 is not operated (accelerator OFF), the accelerator lever 34 is kept in contact with the accelerator fully closed stopper 37 by the accelerator return springs 35 and 36. During the operation of the engine, the position of the accelerator lever 34 is detected by the accelerator sensor 27 as the accelerator operation amount Ap.

On the other hand, a valve lever 38 is connected to a rotation shaft of the throttle valve 15, and the valve lever 38 is urged upward (in the opening direction of the throttle valve 15) by a retreat traveling spring 39. When the electromagnetic clutch 16 interposed between the DC motor 17 and the throttle valve 15 is disengaged (when the clutch is off)
As shown in FIG. 2B, the valve lever 38 is held in contact with the intermediate lever 40 by the retreat traveling spring 39. The intermediate lever 40 is urged downward by a valve return spring 41 (in a direction in which the throttle valve 15 is closed).

The pulling force of the valve return spring 41 is set to be larger than the pulling force of the retreat running spring 39. Therefore, when the electromagnetic clutch 16 is disengaged (when the clutch is OFF), as shown in FIG. 2B, the tensile force of the valve return spring 41 overcomes the tensile force of the retreat traveling spring 39, and The lever 40 is held in contact with the intermediate stopper 42, whereby the opening of the throttle valve 15 is maintained at the opening (about 3 deg) regulated by the intermediate stopper 42.

On the other hand, when the electromagnetic clutch 16 is connected (when the clutch is on), the opening of the throttle valve 15 is adjusted by rotating the DC motor 17 forward or backward according to the operation of the accelerator pedal 26. The opening degree (throttle opening degree) TA of the throttle valve 15 at that time is detected by the throttle sensor 18. At this time, when opening the throttle opening TA, the DC motor 17 is rotated forward and the valve lever 38 is pulled against the intermediate lever 4 against the pulling force of the valve return spring 41 as shown in FIG.
While increasing 0, the throttle valve 15 is driven in a direction to open the opening. Conversely, throttle opening TA
When closing the throttle valve 15, the DC motor 17 is rotated in the reverse direction to drive the throttle valve 15 in the closing direction while lowering the valve lever 38, and the throttle valve 15 is closed to the fully closed stopper position (throttle opening = 0 deg). Then, the valve lever 38 comes into contact with the throttle fully closed stopper 43, and further rotation is prevented.

When the accelerator pedal 26 is operated during the operation of the internal combustion engine 11, the electronic control unit 25 calculates the target opening TTA as will be described later, and sets the throttle opening T
Feedback control is performed based on the output signal of the throttle sensor 18 so that A matches the target opening degree TTA.
Hereinafter, each process for throttle control by the electronic control unit 25 will be described.

The main routine shown in FIG. 3 is repeatedly executed by the electronic control unit 25 at a cycle of, for example, 4 ms after an ignition switch (not shown) is turned on. When the processing of the main routine is started, first, in step 101, an initial check (initialization processing)
Execute In this initial check, a check is made as to whether there is a communication abnormality in each section of the electric system, a mirror check of the initial value of the RAM 31, and the like are performed. Thereafter, in step 102, signals from the various sensors and switches described above are read, and in the next step 103, a non-linear control routine is executed based on the various signals, and the accelerator opening is performed using the map shown in FIG. A target opening degree TACC of the throttle valve 15, which is controlled nonlinearly with respect to the degree Ap, is calculated.

Thereafter, at step 104, a traction control routine is executed to calculate a target opening TTRC of the throttle valve 15 according to the traction control amount of the vehicle. Then, in the next step 105, a constant speed traveling control routine is executed to calculate the initial opening of the throttle valve 15 at the time of transition to the constant speed traveling control mode, and the vehicle speed detected through a vehicle speed sensor (not shown). The target opening TCRC of the throttle valve 15 for making the actual vehicle train coincide with the target vehicle speed is calculated.

In the next step 106, an idle speed control (ISC) routine is executed to calculate a target opening TIDL of the throttle valve 15 during idling.
Thereafter, in step 107, a fail control routine is executed, and the opening of the throttle valve 15 for retreating by control of the motor 17, for example, when the electromagnetic clutch 16 is fixed or the return spring 41 is broken, that is, when the fail occurs, Target opening TF of throttle valve 15
AIL is calculated.

Thereafter, at step 108, a non-linear control routine based on the driver's request determination shown in FIG. 5 is executed, and the accelerator speed is compared with a reference value described later, thereby obtaining the driver's request (for example, smooth driving). Or fast acceleration), the control characteristic of the throttle opening is changed according to the driver's request, and the non-linear target opening TACC according to the driver's request determination is calculated.

Thereafter, at step 109, the non-linear control, traction control, constant speed traveling control, 1SC control, fail control, calculated at steps 103 to 107 described above,
Then, the final target opening degree TTA is calculated according to the following procedures (1) to (5) based on each target opening degree determined by the driver's request.

(1) Compare the non-linear target opening TACC and the constant speed target opening TCRC and select the larger one. (2) Compare the selected value with the traction target opening TTRC and select the smaller one. (3) Compare the selected value with the fail target opening TFAIL and select the smaller one. (4) If the constant speed traveling control, the traction control, and the fail control are not executed, the process proceeds to step 10 instead of the nonlinear target opening degree TACC by the nonlinear control in step 103.
The non-linear target opening degree TACC according to the driver request determination of No. 8 is selected. (5) When the target opening selected in (1) to (4) is
The final target opening TTA is calculated by adding the C target opening TIDL.

Thereafter, in step 110, based on the preset opening-voltage conversion map, the above-mentioned step 109 is performed.
Is converted to the target voltage TTP. After that, in step 111, the target voltage TTP is compared with the output voltage TA of the throttle sensor 18, and in order to reduce the deviation, proportional (P), integral (I), and derivative (D)
Processing is performed to calculate the drive amount (control amount) of the DC motor 17.

Then, in the next step 112, the drive amount is converted into a duty ratio signal, and the duty ratio signal is applied to the DC motor 17 via the driver 32 by the PW motor.
Perform M output processing. As a result, the throttle valve 15
Is driven by the DC motor 17 to generate the target voltage TT.
Feedback control is performed to the opening degree commanded by P. During this feedback control, the electromagnetic clutch 16 is kept in the ON state.

Next, a non-linear control routine based on the driver's request judgment executed in step 108 will be described with reference to FIG. In this routine, first, step 121
Then, the accelerator speed is detected as a physical quantity indicating the mode of the accelerator operation. The detection of the accelerator speed is performed by detecting the change amount of the accelerator opening in a span (for example, 16 ms) longer than the execution cycle (4 ms) of the main routine in FIG. Then, in the next step 122, the accelerator speed is compared with the reference value learned and corrected in step 127, which will be described later, and the driver's request (for example, whether the driver wants to run smoothly,
It is determined that the user wants to accelerate quickly), and the non-linear target opening TACC is set as follows according to the determination result.

(1) When the accelerator speed is less than 0, that is, when the accelerator opening changes in a direction of decreasing,
Proceeding to step 123, without changing the nonlinear characteristic shown in FIG. 4, the nonlinear target opening TA obtained in step 103 of FIG.
Adopt CC as it is.

(2) When 0 ≦ acceleration speed ≦ reference value,
In other words, if the driver is requesting moderate acceleration,
Proceeding to step 124, the nonlinear characteristic shown in FIG. 4 is not changed and the step 103 in FIG.
In step 125, the non-linear target opening TACC obtained in step (1) is used to smooth the non-linear target opening TACC by the following equation.

TACC (i) = TACC (i-1) + ｛TAC
C (i) −TACC (i−1)｝ / 64 By the smoothing process, the change in the non-linear target opening TACC becomes smooth, and a gradual acceleration can be obtained. The above equation is 1
/ 64 smoothing type, for example, 1/32 smoothing, 1/32
The averaging coefficient such as 128 averaging may be appropriately set.

(3) If the accelerator speed is greater than the reference value, that is, if the driver has requested an acceleration response, the routine proceeds to step 126, where the nonlinear characteristic shown in FIG.
The non-linear target opening TACC with respect to the accelerator opening is increased as compared with FIG. 4 (the increasing ratio is set to be large in the low opening region). As a result, the movement of the throttle opening in response to the accelerator depression is increased, and a quick acceleration with a good response to the accelerator depression is obtained. In this case, the non-linear target opening T obtained by the non-linear characteristics shown in FIG.
The non-linear target opening TACC may be changed by multiplying ACC by a constant K (K> 1).

The processing of steps 122 to 126 described above functions as a control characteristic changing means described in the claims.

After performing any one of the above-described steps 123, 125, and 126, the process proceeds to step 127, and FIG.
And a reference value learning routine shown in FIG. In this reference value learning routine, first, in step 131, the maximum accelerator speed PAMAX is detected. The detection of the maximum accelerator speed PAMAX is performed, for example, for each traveling mode (for each start acceleration, each overtaking acceleration, etc.). Thereafter, step 132
The value PAMAX50 at the cumulative 50% point of the maximum accelerator speed PAMAX and the value PA at the cumulative 15% point
MAX15, the value of the cumulative minimum% point PAMAXmin is detected.

Here, PAMAX50, PAMAX15, P
AMAXmin will be described with reference to FIG. FIG.
Maximum accelerator speed PAM of accelerator operation performed by driver
It is the graph which showed distribution of AX (corresponding to the accelerator operation statistical data distribution in a claim) on lognormal probability paper. The horizontal axis of this graph shows the maximum accelerator speed PAMAX on a logarithmic scale, and the vertical axis shows the cumulative frequency on a normal probability scale. In general, the distribution of the maximum accelerator speed PAMAX is approximated by a straight line bent at one inflection point, and a region where the maximum accelerator speed PAMAX is smaller than the inflection point is a region where the driver requests a gentle acceleration. A region where the maximum accelerator speed PAMAX is larger than the inflection point is a region where the driver requests an acceleration response. The average frequency of inflection points for ordinary drivers is around 30%,
This inflection point deviates depending on the driving temperament of the driver. PAM
AX50, PAMAX15, and PAMAXmin are the maximum accelerator speeds at points of 50%, 15%, and minimum (for example, 1%) of the cumulative values, respectively.
Are selected as points at which the intervals in the vertical axis direction of each point are substantially equal.

PAMAX50, PAMAX15, PAMAX
The processing for detecting min is performed by the PAMAX cumulative n% shown in FIG.
This is performed by the point detection routine as follows. First, in step 161, the current maximum accelerator speed PAMAX is set to the value of the previous cumulative n% point PAMAXn (n = 50, 15, min).
), When PAMAX> PAMAXn,
Proceeding to step 162, the constant β from the previous PAMAXn
The value obtained by adding 3 is defined as a new PAMAXn. PAMA
If X <PAMAXn, the process proceeds to step 163,
A value obtained by subtracting the constant β4 from the previous PAMAXn is defined as a new PAMAXn. When PAMAX = PAMAXn, the previous PAMAXn is used as it is. Note that β
3, β4 are set so that the updated value of PAMAXn becomes the value of the cumulative n% point. For example, when n = 50%, β
3 = β4 = Δ (for example, 1) may be set.

By such processing, the value PA of the cumulative n% point is obtained.
After detecting MAXn, the routine proceeds to step 133 in FIG. 6, where it is determined whether or not a reference value update counter CAdp, which counts up each time the first determination value PAL (see FIG. 10) is updated, exceeds a predetermined value α1. If CAdp ≦ α1, the routine proceeds to step 134, where the first counter CLow or the second counter
It is determined whether or not an inflection point update counter CBRK, which counts up each time the counter CHigh is updated, exceeds a predetermined value α2. If CBRK ≦ α2, step 1
In step 35, the maximum accelerator speed PAMAX is compared with a first determination value PAL for determining an inflection point.
If X ≦ PAL, the routine proceeds to step 136, where the first counter CLow is counted up, and the routine proceeds to step 137. On the other hand, if PAMAX> PAL, the process proceeds to step 137 without counting up the first counter CLow.

In step 137, the second judgment value P
AH is calculated by the following equation, and it is determined whether PAH≤PAMAX. PAH = PAMAX50 · (PAMAX50 / PAL) The above equation is an equation for calculating each value without performing logarithmic conversion, but may be calculated by the following equation after each value is logarithmically converted. PAH = PAMAX50 + (PAMAX50-PAL)

As is apparent from this equation, PAH> PA
MAX50> PAL, and FIG.
As shown in (a), the points PAH, PAMAX50, and PAL have the same logarithmic scale in the horizontal axis direction.

Then, when PAMAX ≦ PAH,
Proceeding to step 138, the second counter CHigh is counted up, and in the next step 151, the inflection point update counter CBRK is counted up, followed by terminating the present routine. If PAMAX> PAH, the second counter CHigh is not counted up, and
In step 1, the inflection point update counter CBRK is counted up, and this routine is terminated.

Thereafter, if it is determined in step 134 that the inflection point update counter CBRK has exceeded the predetermined value α2, the flow advances to step 139 to compare the second counter CHigh with the first counter CLow. Here, CHigh> CLow until the inflection point matches PAL or PAH (provided that the inflection point exists between PAL and PAH), and the routine proceeds to step 140, where the first judgment value PAL is obtained. And a predetermined value β1 is added to a new first determination value PAL. On the other hand, if CHigh ≦ CLow, step 14
Proceeding to 1, the value obtained by subtracting the predetermined value β1 from the first judgment value PAL is set as a new first judgment value PAL. Step 1
After the completion of step 40 or step 141, the process proceeds to step 152, in which CBRK, CHigh, and CLow are cleared, and furthermore, CAdp
Is incremented.

By repeating the processing of steps 131 to 141 described above many times, the first judgment value PAL is obtained.
Alternatively, the second judgment value PAH is made to coincide with the inflection point.

Thereafter, if it is determined in step 133 that the reference value update counter CADp has exceeded the predetermined value α1, the process proceeds to step 142 in FIG. 7 to determine whether or not the following relationship is satisfied. PAMAX50 / PAMAX15> PAMAX15 / PAMA
Xmin + γ

In the above equation, γ is a constant added for the purpose of giving a width (margin) to the comparison result. The above equation is an equation in a case where each value is calculated without performing logarithmic conversion. However, the determination may be performed by the following equation after each value is logarithmically converted. PAMAX50-PAMAX15> PAMAX15-PAMA
Xmin + γ '

If the above expression is satisfied, the routine proceeds to step 143, where the reference value is compared with the first judgment value PAL, and the reference value>
In the case of PAL, the process proceeds to step 144, where the learning value BR
The learning value BRK is updated with a value obtained by subtracting the predetermined value β2 from K. If the reference value ≦ PAL, the process proceeds to step 145,
The learning value BRK is a value obtained by adding a predetermined value β2 to the learning value BRK.
To update.

If the determination in step 142 is "No", the process proceeds to step 146, where the reference value is compared with the second determination value PAH. If the reference value> PAH, the process proceeds to step 147. Advances to the predetermined value β from the learning value BRK.
The learning value BRK is updated with the value obtained by subtracting 2, and the reference value ≦ PA
In the case of H, the routine proceeds to step 148, where the learning value BRK is updated with a value obtained by adding a predetermined value β2 to the learning value BRK.

After the learning value BRK is updated by the above processing, the routine proceeds to step 149, where the learning value BRK is added to the preset initial value PALEV of the reference value to update the reference value. Thereby, as shown in FIG. 10B, the reference value is made to coincide with the inflection point (PAL or PAH) of the distribution. Then, in the next step 150, the above-mentioned CAdp is cleared, and this routine ends. The reference value learning routine described above functions as a learning means described in the claims.

As shown in FIG. 8, a region where the driver requests an acceleration response and a region where a gentle acceleration is requested are divided at the inflection point of the distribution of the maximum accelerator speed. Therefore, if the reference value is learned and corrected by the above-described reference value learning routine so that the reference value matches the inflection point of the distribution, the driver's request for acceleration can be accurately reflected in the throttle control. Moreover, since the maximum accelerator speed distribution also reflects vehicle manufacturing variations, setting the reference value according to the inflection point of this distribution achieves stable throttle control that is not affected by vehicle manufacturing variations. In addition to this, special processing for absorbing manufacturing variations of the vehicle is not required, and the number of adaptation steps and ROM capacity can be reduced, which is advantageous in terms of cost.

<< Embodiment (2) >> In this embodiment (2), the reference value learning routine shown in FIG. 11 is executed as follows instead of the reference value learning routine shown in FIGS. 6 and 7. First, in step 201, for example, the maximum accelerator speed PAMA is set for each traveling mode (for each start acceleration, each overtaking acceleration, etc.).
X is detected. Thereafter, in step 202, a value PAMAXn of the cumulative n% point of the maximum accelerator speed PAMAX statistic so far is detected. Here, the cumulative n% points to be detected are, for example, maximum% point, 95% point, 85% point, 70% point,
The 50% point, the 30% point, the 15% point, the 5% point, and the minimum% point, and points at which the intervals in the vertical axis direction of each point are substantially equal are selected.

Then, in the next step 203, Δ = (PAMAXn-PAMAXn-1)-(PAMAX
(n-1-PAMAXn-2) is detected and n is set as nBRK. Here, as shown in FIG. 12, the n point at which the above Δ becomes maximum is:
This is a point where the inflection point of the distribution exists between the n point and the n-1 point. Therefore, the position of the inflection point can be narrowed down by detecting the n point (= nBRK point) at which Δ becomes maximum. In this case, in order to improve the detection accuracy of the inflection point, n points and n−1
It is necessary to narrow the interval between the points, and for that purpose, it is necessary to increase the number of detection points in step 202.

Thereafter, at step 204, the reference value is compared with PAMAXnBRK. If the reference value is greater than PAMAXnBRK, the routine proceeds to step 205, where the learning value BRK is updated with a value obtained by subtracting the predetermined value β2 from the learning value BRK. To step 208. On the other hand, reference value ≦ PAMAXnB
In the case of RK, the process proceeds to step 206 and the reference value is set to PAM.
AXnBRK-1 and if the reference value is smaller than PAMAXnBRK-1, the routine proceeds to step 207, where the learning value BRK is set to the predetermined value β.
The learning value BRK is updated with the value obtained by adding 2 to step 2.
Proceed to 08. Also, PAMAXnBRK-1 ≦ reference value ≦ PAM
In the case of AXnBRK, the process proceeds to step 208 without updating the learning value BRK.

In step 208, the learning value BRK is added to the preset initial value PALEV of the reference value to update the reference value, and the routine ends. By repeating such processing, the reference value is made to substantially match the inflection point of the distribution.

The reference value learning routine of FIG. 11 described above has the advantage that the number of steps in the program is smaller than that of the reference value learning routine of FIGS. 6 and 7, and the reference value can be learned quickly.

<< Embodiment (3) >> In this embodiment (3), a reference value learning routine shown in FIG. 13 is used instead of the reference value learning routine shown in FIG. The reference value learning routine in FIG. 13 is obtained by replacing the processing in steps 204 to 208 in FIG. That is, in the reference value learning routine of FIG.
3, the detection of the maximum accelerator speed PAMAX, the detection of the cumulative n% point PAMAXn, the existence range of the inflection point of the distribution (PAM
AXnBRK, PAMAXnBRK-1) is detected. And
Considering that the inflection point is located between PAMAXnBRK and PAMAXnBRK-1, in step 204, PAMAXnB
The average value of RK and PAMAXnBRK-1 is calculated and used as a reference value (= inflection point).

By doing so, the number of steps of the program for the learning process is further reduced as compared with FIG. 11, and the learning speed of the reference value can be further increased.

<< Embodiment (4) >> In each of the above-described embodiments (1) to (3), learning is performed so that the reference value matches the inflection point of the accelerator speed distribution.

On the other hand, in the embodiment (4) shown in FIGS. 14 and 15, attention is paid to the point that the position of the inflection point of the accelerator speed distribution statistic for a general driver is about 30% cumulatively. The value PAMAX30 at the cumulative 30% point is set as a reference value. This process is executed as follows by the reference value learning routine of FIG.

First, in step 301, the maximum accelerator speed PAMAX is detected for each traveling mode (for each starting acceleration, each overtaking acceleration, etc.). Thereafter, at step 302, the cumulative 3
The value PAMAX30 at the 0% point is detected. Next Step 30
3, the standard deviation PASG of the maximum accelerator speed PAMAX
After detecting M, in step 304, the value PAMAX30 of the cumulative 30% point of the maximum accelerator speed PAMAX is set as a reference value. Note that the standard deviation PASGM obtained in step 303 is used to give hysteresis to the control characteristic that changes the nonlinear characteristic in the nonlinear control routine based on the driver request determination in FIG.

On the other hand, the non-linear control routine based on the driver request determination in FIG. 15 is basically the same as the routine in FIG. 5, and the steps for performing the same processing as in FIG. Is omitted. In this routine, after detecting the accelerator speed in step 121, step 1 is executed.
At 21a, it is determined whether the hysteresis flag FLAG is set to "1". Here, FLAG = 0
In the case of (1), the routine proceeds to step 122, where the accelerator speed is compared with the reference value.
Proceeding to 2a, the accelerator speed is compared with the reference value + PASGM. That is, the reference value + PASGM is regarded as a new reference value, and a hysteresis is provided by comparing with the accelerator speed. Then, the above step 121a or 122
Steps 123, 124, 126 according to the determination result of a
Is determined, the nonlinear characteristic is changed, or the nonlinear target opening degree TACC is set without changing the nonlinear characteristic.

When step 126 or 123 is executed, the hysteresis flag FLAG is reset to "0", and when steps 124 and 125 are executed, the hysteresis flag FLAG is set to "1".

In the embodiment (4) described above, the position of the inflection point of the accelerator speed distribution is accumulated 3 for a general driver.
Paying attention to the point of about 0%, the value of the cumulative 30% point PAMA
Since X30 is used as the reference value, there is an advantage that the processing can be further simplified. However, in the present invention, the value PAM of a point other than the cumulative 30%, such as the cumulative 25%, the cumulative 35%, the cumulative 40%, etc.
AXn may be used as the reference value.

In the embodiment (4), since the standard deviation PASGM of the accelerator speed distribution is used as the data for setting the hysteresis in the control characteristics, there is an advantage that the hysteresis with high accuracy according to the accelerator speed distribution can be set. . However, in the present invention, this hysteresis may be set to an appropriate value in the design stage in advance.

<< Embodiment (5) >> In the above-described embodiments (1) to (4), the accelerator speed is used as the physical quantity indicating the mode of the accelerator operation, but the accelerator acceleration or the accelerator depression amount may be used. . In this embodiment (5), in the non-linear control routine based on the driver request determination in FIG. 16, the non-linear characteristic is obtained by using not only the accelerator speed PA but also the accelerator acceleration DPA and the accelerator depression amount ΔPA as the physical quantity indicating the mode of the accelerator operation. It is determined whether or not there is a change.

In the routine shown in FIG.
In step 1, the accelerator speed PA is detected, and the following step 121 is executed.
In steps b and 121c, an accelerator acceleration DPA and an accelerator depression amount ΔPA are detected. Thereafter, in step 122b, the accelerator speed PA, the accelerator acceleration DPA, and the accelerator depression amount ΔPA are compared with the respective reference values, and based on the comparison result, it is determined which of steps 123, 124, and 126 to proceed to, and the nonlinear characteristic is determined. The non-linear target opening degree TACC is set with or without changing.

In this case, the reference value to be compared with the accelerator acceleration DPA and the reference value to be compared with the accelerator depression amount ΔPA are:
What is necessary is just to set by the same process as the reference value learning routine of the above-mentioned Embodiments (1) to (4). In step 122b, the accelerator speed PA and the accelerator acceleration DP
A, the comparison result between the accelerator depression amount ΔPA and each reference value is determined by OR, but the determination may be made by appropriately combining the three comparison results.

According to the embodiment (5) described above, three physical quantities of the accelerator speed, the accelerator acceleration, and the accelerator pedal depression amount are used as the physical quantities indicating the mode of the accelerator operation in order to improve the control accuracy. Any one of these physical quantities or two physical quantities may be used.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire internal combustion engine control system showing an embodiment (1) of the present invention.

FIG. 2 is a schematic configuration diagram of an electronic throttle system.
(A) is a diagram showing a state at the time of normal control (when the clutch is ON), and (b) is a diagram showing a state at the time of clutch OFF.

FIG. 3 is a flowchart showing the flow of processing of a main routine.

FIG. 4 shows a relationship between the accelerator opening Ap and the non-linear target opening TACC.
Figure showing a map for setting

FIG. 5 is a flowchart showing the flow of processing of a non-linear control routine based on driver request determination;

FIG. 6 is a flowchart showing a processing flow of a reference value learning routine (part 1);

FIG. 7 is a flowchart showing the flow of a reference value learning routine (part 2);

FIG. 8 is a diagram showing a distribution of a maximum accelerator speed PAMAX of an accelerator operation performed by a driver on a lognormal probability paper.

FIG. 9 is a flowchart showing a processing flow of a PAMAX cumulative n% point detection routine;

FIG. 10 is a distribution diagram for explaining a process of detecting an inflection point of the distribution.

FIG. 11 is a flowchart showing the flow of processing of a reference value learning routine used in the embodiment (2) of the present invention.

FIG. 12 is a distribution diagram for explaining a process of detecting an inflection point of the distribution.

FIG. 13 is a flowchart showing the flow of processing of a reference value learning routine used in the embodiment (3) of the present invention.

FIG. 14 is a flowchart showing the flow of a reference value learning routine used in the embodiment (4) of the present invention;

FIG. 15 is a flowchart showing the flow of processing of a non-linear control routine based on a driver request determination;

FIG. 16 is a flowchart showing a flow of a non-linear control routine based on a driver request determination used in the embodiment (5) of the present invention.

[Explanation of symbols]

11 internal combustion engine, 12 intake pipe, 14 air flow meter, 15 throttle valve, 16 electromagnetic clutch, 1
7: DC motor (throttle driving means), 18: throttle sensor, 25: electronic control unit (control characteristic changing means, learning means), 26: accelerator pedal, 27: accelerator sensor, 34: accelerator lever, 35, 36: accelerator Return spring, 37 ... accelerator fully closed lever, 3
8: Valve lever, 39: Escape spring, 40
... Intermediate lever, 41 ... Valve return spring, 42
... Intermediate stopper, 43 ... Throttle fully closed stopper.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication F02D 45/00 358 F02D 45/00 358H

Claims (8)

[Claims] 1. An electronic throttle control for an internal combustion engine, comprising: throttle drive means for driving a throttle valve; and controlling the throttle drive means to match a throttle opening with a target throttle opening set according to an accelerator operation. In the device, the distribution of physical quantities indicating the mode of past accelerator operations performed by the driver (hereinafter referred to as “accelerator operation statistical data distribution”)
An electronic throttle control device for an internal combustion engine, comprising: a control characteristic changing unit that changes a control characteristic of a throttle opening degree with respect to an accelerator operation in accordance with the accelerator operation statistical data distribution. 2. The physical quantity indicating the mode of the accelerator operation includes an accelerator speed at the time of accelerator operation, an accelerator acceleration,
2. The electronic throttle control device for an internal combustion engine according to claim 1, wherein the electronic throttle control amount is at least one of an accelerator depression amount. 3. The control characteristic changing unit compares a physical quantity indicating a current mode of the accelerator operation with a predetermined reference value to determine whether to change the throttle opening control characteristic, and 3. The electronic throttle control device for an internal combustion engine according to claim 1, further comprising: learning means for learning and correcting the reference value based on an accelerator operation statistical data distribution. 4. The electronic throttle control device for an internal combustion engine according to claim 3, wherein the learning means performs learning correction so that the reference value matches an inflection point of the accelerator operation statistical data distribution. . 5. The control characteristic changing unit sets a physical quantity that changes according to the accelerator operation statistical data distribution as a reference value, and compares a physical quantity indicating a mode of the current accelerator operation with the reference value. 3. The electronic throttle control device for an internal combustion engine according to claim 1, further comprising: means for determining whether to change the control characteristic of the throttle opening. 6. The control characteristic changing unit uses at least one of an inflection point, a standard deviation, and a median of the accelerator operation statistical data distribution as the physical quantity for setting the reference value. Item 6. An electronic throttle control device for an internal combustion engine according to Item 5. 7. The control characteristic changing unit according to claim 5, wherein the control characteristic changing unit uses, as the physical quantity for setting the reference value, an amount at which the cumulative frequency in the accelerator operation statistical data distribution becomes a predetermined percentage. Electronic throttle control device for internal combustion engine. 8. The control characteristic changing means, when a physical quantity indicating a mode of the current accelerator operation is equal to or less than the reference value,
8. The electronic throttle control device for an internal combustion engine according to claim 3, wherein the control characteristic is changed to a control characteristic that makes the drive speed of the throttle valve slower than in other cases.