JP4082487B2 - Electronic throttle control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic throttle control device having an opener mechanism, and more particularly to an electronic throttle control device that learns a throttle fully closed point position when an ignition is OFF.
[0002]
[Prior art]
Conventionally, in an engine equipped with this type of electronic throttle control device (ETC), for example, as disclosed in Japanese Patent Laid-Open No. 10-47115, an operation amount of an accelerator pedal of a driver is detected by an accelerator opening sensor. The target throttle opening is set based on the accelerator opening detected by the accelerator opening sensor, and the throttle valve opening is feedback controlled so as to match the target throttle opening, in accordance with the driver's intention. The engine output is obtained.
[0003]
Further, in this type of electronic throttle control device, in order to prevent the throttle valve and the throttle shaft from icing and being unable to start at low temperatures such as in cold regions, a failure has occurred in the electronic throttle control device. Even in this case, when energization to the throttle motor is turned off to ensure retreat travel, the throttle valve is slightly opened from the fully closed position by a mechanical biasing force such as a spring (hereinafter referred to as “opener position”). It is set so as to hold.
[0004]
Therefore, in the case of controlling the opening degree of the throttle valve based on the throttle fully closed position, the throttle valve is forcibly rotated to the fully closed position at least one of when the ignition is turned off or when the ignition is turned on. At this time, the throttle fully closed position is detected based on the output value of the throttle opening sensor.
[0005]
However, even if the throttle fully closed point position is learned when the ignition is OFF, the sensor output indicating the throttle fully closed point position may fluctuate due to the influence of temperature characteristics, etc. at the time of starting after being left, There's a problem.
[0006]
On the other hand, in the technique of learning the throttle fully closed position when the ignition is turned on, the engine cannot be started until learning of the throttle fully closed position is completed, and therefore it can be started immediately even if the starter switch is turned on. This is not possible, and the driver feels uncomfortable due to the slack at the start.
[0007]
In order to deal with this, for example, in Japanese Patent Laid-Open No. 6-108897, the throttle fully closed position is learned when the ignition is turned on, and at that time, the starter switch is turned on before learning of the throttle fully closed position is completed. In such a case, a technique for canceling learning of the throttle fully closed position is disclosed.
[0008]
[Problems to be solved by the invention]
However, in the above-described prior art, when the starter switch is turned on, the learning of the throttle fully closed point position is canceled. However, there is an individual difference in the time from when the ignition is turned on to when the starter switch is turned on. For drivers who have a habit of turning on the starter switch in a relatively short time after the ignition is turned on, the opportunity to learn the throttle fully closed position is extremely reduced, and the throttle opening is accurately detected. Has the disadvantage of becoming difficult.
[0009]
In view of the above circumstances, the present invention can obtain a good startability without causing the driver to feel unsatisfactory at the time of starting, and extremely reduce the opportunity for learning the throttle fully closed point. It is another object of the present invention to provide an electronic throttle control device that can detect the throttle fully closed point with high accuracy.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a first electronic throttle control device according to the present invention comprises throttle drive means for opening and closing a throttle valve, throttle opening detection means for detecting the throttle opening of the throttle valve, and throttle drive means. An opener mechanism that holds the throttle valve at a preset opener position when the engine is turned off, and the throttle opening detected by the throttle opening detection means when the throttle valve is rotated to the fully closed position when the ignition is off. From the throttle opening detected by the throttle opening detection means of the throttle valve that is held at the opener position when ignition is turned on, and the throttle opening position learning means that learns the throttle closing position based on the opening, The throttle fully closed position and the opener position set in advance A fully closed point estimating means for calculating an estimated throttle fully closed point position by subtracting an opener set opening between, and a comparing means for comparing the throttle fully closed position with the estimated throttle fully closed position, When the comparison value between the throttle full-close position and the estimated throttle full-close position exceeds a preset first upper limit value, the full-close point position learning means has the throttle drive means before starting. And a resetting means for relearning the throttle fully closed position based on the throttle opening detected by the throttle opening detecting means when the throttle valve is fully closed.
[0011]
In such a configuration, when the ignition is OFF, the throttle valve is fully closed by the throttle driving means, and the throttle fully closed position is learned based on the throttle opening detected by the throttle opening detecting means at that time. Then, when the ignition is turned on thereafter, the estimated throttle fully closed point position set by subtracting the opener position from the throttle opening detected by the throttle opening detecting means is compared with the throttle fully closed point position learned when the ignition is turned off. When the comparison value exceeds the preset first upper limit value, the throttle valve is fully closed by the throttle driving means before starting, and the throttle fully closed position based on the throttle opening at that time To learn again. As a result, when this comparison value is within the first upper limit value, it is not necessary to learn the throttle fully closed point position again, and it is possible to start better than when the throttle fully closed point position is learned every time the ignition is turned on. Sex can be secured.
[0012]
The fully closed position learning means is lower than the first upper limit even if the comparison value between the throttle fully closed position and the estimated throttle fully closed position is less than or equal to the first upper limit. When the second upper limit value set in advance is exceeded, a fully closed point position learning correction unit is provided for correcting the throttle fully closed point position and setting a new throttle fully closed point position. .
[0013]
In such a configuration, even if the comparison value between the throttle fully closed position and the estimated throttle fully closed position is equal to or less than the first upper limit value, a preset second upper limit value that is lower than the first upper limit value. Since the throttle fully closed position is corrected and a new throttle fully closed position is set, the throttle fully closed position after ignition is turned on is secured while ensuring good startability. High accuracy can be set.
[0014]
In this case, it is preferable that 1) the fully closed point position learning correction means is configured so that the throttle fully closed point is based on an average value of the throttle fully closed position and the estimated throttle fully closed position set when the ignition is off. The position is corrected.
[0015]
2) The fully closed point position learning correction means is based on the difference in the throttle opening detected by the throttle opening detection means of the throttle valve at the opener position read when the ignition is on and when the ignition is off. Then, the correction term is calculated, and the throttle fully closed position is corrected by the correction term .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electronic throttle control device, and FIG. 2 is a schematic configuration diagram of an electronic throttle including an opener mechanism.
[0017]
As shown in FIG. 1, an electronic throttle control device (ETC) includes an electronic throttle 2 provided in the throttle body 1, a control unit (ECU) 3 for controlling the electronic throttle 2, and an accelerator pedal module having an accelerator pedal 4a. 4. An opener mechanism 11 (see FIG. 2) is provided. Further, the accelerator pedal module 4 is provided with an accelerator opening sensor 6 as an accelerator opening detecting means composed of a potentiometer or the like for detecting the depression angle (accelerator opening) of the accelerator pedal 4a.
[0018]
In addition, the throttle valve 5 interposed in the throttle body 1 and the accelerator pedal module 4 are not mechanically connected, and the throttle valve 5 is a throttle motor as a throttle driving means composed of an electric motor or the like provided therewith. The valve opening degree is controlled by the rotation of 2a. The throttle valve 5 is connected to a throttle opening sensor 2b as a throttle opening detecting means for detecting the actual throttle opening of the throttle valve 5. The throttle motor 2a, the throttle valve 5, the throttle opening sensor 2b, and the throttle shaft 5a that supports the throttle valve 5 constitute the electronic throttle 2.
[0019]
The throttle opening sensor 2b is a contact type sensor composed of a potentiometer or the like, or a non-contact type sensor using a Hall IC or the like. The throttle opening is detected on the basis of “sensor output”.
[0020]
The control unit (ECU) 3 is mainly composed of a microcomputer including a CPU 7, a ROM (not shown), a RAM (not shown) and the like, and an accelerator opening sensor 6 is connected to the CPU 7 on the input side. The throttle opening sensor 2 b is connected via the A / D converter 9 while being connected via the / D converter 8.
[0021]
The CPU 7 detects the actual opening of the throttle valve 5 based on the sensor output from the throttle opening sensor 2b.
[0022]
On the other hand, a throttle motor 2 a is connected to the output side of the CPU 7 via a drive circuit 10.
[0023]
When the driver steps on the accelerator pedal 4a, a signal proportional to the depression angle (accelerator opening) of the accelerator pedal 4a is output from the accelerator opening sensor 6 to the CPU 7 via the A / D converter 8.
[0024]
The CPU 7 sets the torque requested by the driver based on the accelerator opening detected by the accelerator opening sensor 6, sets the target required torque based on the required torque, and sets the target throttle opening based on the target required torque. . Then, a drive signal corresponding to the target throttle opening is output to the throttle motor 2a to open / close the throttle valve 5 in a predetermined manner, and based on the actual throttle opening detected by the throttle opening sensor 2b, the throttle valve 5 Is feedback controlled so as to converge to the target throttle opening.
[0025]
As shown in FIG. 2, the opener mechanism 11 connected to the electronic throttle 2 opens the throttle valve 5 slightly from the fully closed state when the power supply to the throttle motor 2a is stopped (the throttle motor 2a is OFF). (A) is a schematic diagram when the throttle valve 5 is in the opener position, and (b) is a state in which the throttle valve 5 is controlled in the valve opening direction. A schematic diagram and FIG. 10C are schematic diagrams when the throttle valve 5 is in a fully closed state.
[0026]
The opener mechanism 11 is connected to the shaft end of the throttle shaft 5a opposite to the shaft end where the throttle motor 2a is connected. The opener mechanism 11 is provided with an opener lever 12 for holding the throttle valve 5 at a predetermined opener position when energization to the throttle motor 2a is stopped by the ignition OFF. Further, one end of a return spring 13 that biases the throttle valve 5 in the closing direction is fixed to the opener lever 12, and the other end of the return spring 13 is fixed to a throttle housing 14 provided in the throttle body 1. ing.
[0027]
The opener lever 12 is movable in the opening direction integrally with the throttle shaft 5a by the urging force of the return spring 13, and when the throttle valve 5 reaches the fully open position, the opener lever 12 is locked to the fully open stopper 15 and fully opened. Directional movement is restricted. On the other hand, when the throttle valve 5 is rotated in the closing direction, the throttle shaft 5a is locked by a full-close stopper 14a formed in the throttle housing 14, and movement in the full-close direction is restricted. Further, the opener lever 12 and the throttle shaft 5a are biased in a direction in which they are attracted to each other via an opener spring 16.
[0028]
When the throttle shaft 5a is moved in the opening direction against the urging force of the return spring 13 by the driving force of the throttle motor 2a, the throttle shaft 5a is urged in an attracting direction via the opener spring 16. The opener lever 12 is moved together, and the opening of the throttle valve 5 is stopped at the position where the opener lever 12 is hooked on the fully open stopper 15 (fully opened position). Accordingly, the throttle valve 5 during normal operation is opened and closed between the opener position and the fully open position.
[0029]
In this case, the urging force of the return spring 13 is set smaller than the driving force of the throttle motor 2a and larger than the detent torque when the throttle motor 2a is not energized. As a result, when the throttle motor 2a is energized, the throttle valve 5 can be opened and closed against the biasing force of the return spring 13, and when the throttle motor 2a is not energized, the throttle valve 5 is moved in the closing direction by the biasing force of the return spring 13. Attempts to rotate, but since the rotational force is restricted by the biasing force of the opener spring 16, the throttle valve 5 is slightly opened with respect to the throttle fully closed position by the balance of the springs 13 and 16 ( (Hereinafter referred to as “opener position”).
[0030]
The opening (hereinafter referred to as “opener setting opening”) THC of the throttle valve 5 at the opener position is set to an optimum value for each vehicle type in accordance with the engine type, the displacement, and the like.
[0031]
When the throttle motor 2a is not energized, the engine can be started even when the throttle shaft 5a is frozen in a cold region, for example, by stopping the throttle valve 5 at the open position. In addition, during operation, even if the energization to the throttle motor 2a is unexpectedly interrupted, the throttle valve 5 is stopped at the opener position without being fully closed, thereby ensuring a limp home. Can do.
[0032]
On the other hand, when the driving force of the throttle motor 2a is applied to the throttle shaft 5a against the biasing force of the opener spring 16, the throttle shaft 5a moves away from the opener lever 12 and moves toward the fully closed stopper 14a. The throttle shaft 5a is engaged with the fully closed stopper 14a, and the throttle valve 5 is fully closed.
[0033]
By the way, the output characteristic of the throttle opening sensor 2b is likely to fluctuate due to the influence of the temperature characteristic. Therefore, in the case of controlling the throttle opening based on the throttle fully closed position, the reference position at the time of throttle opening control is used. It is necessary to learn the throttle fully closed position.
[0034]
When learning the throttle fully closed position, it is necessary to forcibly fully close the throttle valve 5. However, if the throttle valve 5 is fully closed during engine operation, engine stall may occur. Opportunities are limited to either when the ignition is OFF or when the ignition is ON.
[0035]
The control unit 3 learns the throttle fully closed position when the ignition is OFF, and when the ignition is turned on next time, the previously learned throttle fully closed position THCLS and the throttle valve 5 detected by the throttle opening sensor 2b are in the opener position. The change amount DTHCLS is calculated by comparing the value obtained by subtracting the opener set opening THC from the throttle opening THOPNON at the time. When this change DTHCLS is large, the throttle fully closed point position THCLS learned when the ignition is turned off the last time is calculated. Correct or perform learning again.
[0036]
The learning of the throttle fully closed point position executed by the control unit 3 is specifically processed according to the flowcharts shown in FIGS.
[0037]
That is, when the ignition is turned off, the throttle fully closed point position learning routine shown in FIG. 3 is executed. Note that the self-shut relay operates and the battery power is continuously supplied to the control unit 3 from when the ignition is turned off until the throttle fully closed position is learned.
[0038]
First, in step S1, a drive signal is output to the throttle motor 2a to forcibly rotate the throttle valve 5 to the fully closed position, and the throttle opening detected by the throttle opening sensor 2b at this time is set. Based on this, the throttle fully closed position THCLS stored in the backup RAM is learned.
[0039]
Next, the process proceeds to step S2, and the power supply to the throttle motor 2a is cut off (OFF). Then, the throttle valve 5 is moved to a balanced position between the return spring 13 and the opener spring 16, that is, the opener position, and stopped.
[0040]
Thereafter, the process proceeds to step S3, where the throttle opening THOPN detected by the throttle opening sensor 2b is read, and the opener opening opening THOPNOFF stored in the backup RAM is updated with this throttle opening THOPN (THOPNOFF ← THOPN ) And end the routine.
[0041]
The throttle fully closed point position THCLS and the opener set opening THOPNOFF are read in the throttle fully closed point position learning routine shown in FIG. 4 when the ignition is on.
[0042]
This routine is started when the ignition is turned on. First, in step S11, the throttle opening THOPN detected by the throttle opening sensor 2b is read, and at this throttle opening THOPN, the ON-time opener setting is opened. Degree THOPNON is updated (THOPNON ← THOPN).
[0043]
Next, the process proceeds to step S12, where the opener set opening THC is subtracted from the ON opener set opening THOPNON to set the estimated throttle fully closed position THCLS1 (THCLS1 = THOPNON-THC).
[0044]
Thereafter, in step S13, a change amount DTHCLS is set as an absolute value of a value obtained by subtracting the estimated throttle fully closed position THCLS1 from the throttle fully closed position THCLS read at the time of the previous ignition OFF (DTHCLS = | THCLS−THCLS1 | ).
[0045]
In step S14 and step S15, the change amount DTHCLS, the allowable upper limit value DTHMAX that is the first upper limit value, and the correction target lower limit value DTHMIN that is the second upper limit value are compared.
[0046]
This allowable upper limit value DTHMAX is a limit value when the throttle fully closed point position THCLS is greatly deviated, and this time with respect to the throttle fully closed point position THCLS detected at the time of the previous ignition OFF due to part replacement or battery replacement. It is assumed that the estimated throttle fully closed point position THCLS1 greatly deviates. On the other hand, the correction target lower limit value DTHMIN is slightly different from the estimated throttle full-close point position THCLS1 with respect to the throttle full-close point position THCLS detected at the time of the previous ignition OFF, but the reliability of the throttle full-close point position THCLS is small. Is a limit value that can be secured, and is obtained in advance based on experiments and the like.
[0047]
If it is determined in step S14 that DTHCLS ≧ DTHMAX, it is determined that the reliability of the throttle fully closed position THCLS stored in the backup RAM is low due to parts replacement, battery replacement, etc., and the process branches to step S16. Then, the throttle fully closed point position THCLS is learned again, and the routine is terminated.
[0048]
That is, in step S16, a drive signal is output to the throttle motor 2a to forcibly rotate the throttle valve 5 to the fully closed position, and based on the throttle opening detected by the throttle opening sensor 2b at this time, The throttle fully closed position THCLS stored in the backup RAM is learned. At this time, even if the starter switch is turned on, the starter motor is not started, and is in a standby state until learning of the throttle fully closed position THCLS is completed.
[0049]
Therefore, when the throttle fully closed position THCLS is learned again, the start is slightly delayed, which may give the driver a sense of incongruity. However, the frequency of this relearning is low, and is normally executed in step S17 described later. Therefore, the driver will not be significantly discomforted.
[0050]
If it is determined in step S15 that DTHCLS ≧ DTHMIN, that is, DTHMAX> DTHCLS ≧ DTHMIN, the output of the throttle opening sensor 2b is affected by the temperature characteristics or the like, and an error occurs. Although the deviation is slight, since the reliability of the throttle fully closed position THCLS is low, the process branches to step S17, corrects the throttle fully closed position THCLS, and sets a new throttle fully closed position THCLS. End the routine.
[0051]
The new throttle fully closed point position THCLS calculated in step S17 is, for example, a simple average shown in Expression 1 or a change between the opener opening THOPNON at ON and the opener opening THOPNOFF at OFF as shown in Expression 2. The amount may be obtained as a correction term.
[0052]
[Formula 1]
THCLS ← (THCLS + THCLS1) / 2
[0053]
[Formula 2]
THCLS ← THCLS + (THOPNON-THOPNOFF) ・ K
Here, K is a weight set according to the influence of external factors such as the temperature characteristic of the change amount, and is obtained in advance based on experiments or the like.
[0054]
That is, in Equation 2, the difference between the detected opening set opening THOPNOFF and THOPNON between the previous ignition OFF and the current ignition ON is expressed as the variation factor due to the temperature change from the ignition OFF to the ignition ON. Therefore, the throttle fully closed point position THCLS is corrected with a correction value obtained by multiplying the change amount by the weight K, and a new throttle fully closed point position THCLS is set.
[0055]
If it is determined in step S15 that DTHCLS <DTHMIN, the routine is terminated as it is. Therefore, the throttle fully closed point position THCLS read at the time of the previous ignition OFF becomes the reference position for the current throttle opening control.
[0056]
As described above, in the present embodiment, when a slight deviation occurs in the sensor output of the throttle opening sensor 2b due to an influence of a variation factor such as a temperature characteristic, a correction is used. As a result, the slack at the time of starting is eliminated, and good startability can be obtained. Further, by correcting the throttle fully closed point position THCLS, the throttle fully closed point position THCLS can be set with high accuracy at each start, and good throttle controllability can be obtained.
[0057]
The present invention is not limited to the above-described embodiment. For example, the correction of the throttle fully closed point position THCLS processed in step S17 is performed based on the amount of change in the coolant temperature detected when the ignition is turned off and when the ignition is turned on. You may make it perform according to it.
[0058]
【The invention's effect】
As described above, according to the present invention, when setting the throttle fully closed point position when the ignition is ON, there is no backlash at the time of starting, the discomfort given to the driver is eliminated, and good startability is obtained. Can do.
[0059]
In addition, the opportunity for learning the throttle fully closed point is not drastically reduced, and the throttle fully closed point position can be set with high accuracy at each start, so that good throttle controllability can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an electronic throttle control device. FIG. 2 is a schematic configuration diagram of an electronic throttle including an opener mechanism, (a) is a schematic diagram when a throttle valve is in an opener position, and (b) is a throttle. FIG. 3C is a schematic diagram when the valve is controlled in the valve opening direction. FIG. 3C is a schematic diagram when the throttle valve is in a fully closed state. FIG. 3 is a flowchart showing a throttle fully closed point position learning routine when the ignition is OFF. 4) Flow chart showing the throttle fully closed point position learning routine when the ignition is ON [Explanation of symbols]
2a Throttle motor (throttle drive means)
2b Throttle opening sensor (throttle opening detecting means)
5 Throttle valve 11 Opener mechanism DTHMAX Permissible upper limit (first upper limit)
DTHMIN Correction target lower limit (second upper limit)
THC Opener setting opening THCLS Throttle fully closed position THCLS1 Estimated throttle fully closed position THOPN Throttle opening

Claims (4)

Throttle drive means for opening and closing the throttle valve;
Throttle opening detection means for detecting the throttle opening of the throttle valve;
An opener mechanism for holding the throttle valve in a preset opener position when the throttle driving means is turned off;
A fully closed position learning means for learning a throttle fully closed position based on the throttle opening detected by the throttle opening detecting means when the throttle valve is rotated to a fully closed position when the ignition is off;
Based on the throttle opening detected by the throttle opening detecting means of the throttle valve held at the opener position when the ignition is turned on, an opener between the throttle fully closed position set in advance and the opener position is determined. A fully closed point estimating means for subtracting the set opening and calculating an estimated throttle fully closed position;
Comparison means for comparing the throttle fully closed position with the estimated throttle fully closed position;
With
When the comparison value between the throttle full-close position and the estimated throttle full-close position exceeds a preset first upper limit value, the full-close point position learning means has the throttle drive means before starting. An electronic throttle control device comprising: resetting means for re-learning a throttle fully closed point position based on a throttle opening detected by the throttle opening detecting means when the throttle valve is fully closed. The fully closed point position learning means is
Even if the comparison value between the throttle fully closed position and the estimated throttle fully closed position is less than or equal to the first upper limit value, it exceeds a preset second upper limit value lower than the first upper limit value. 2. An electronic throttle control device according to claim 1, further comprising a full-closed point position learning correction means for correcting the throttle full-closed point position and setting a new throttle full-closed point position. The fully closed point position learning correction means includes:
3. The electronic throttle control device according to claim 2, wherein the throttle full closing point position is corrected based on an average value of the throttle full closing point position set when the ignition is off and the estimated throttle full closing point position. . The fully closed point position learning correction means includes:
A correction term is calculated based on the difference in the throttle opening detected by the throttle opening detection means of the throttle valve at the opener position read when the ignition is on and when the ignition is off. 3. The electronic throttle control device according to claim 2, wherein the throttle fully closed position is corrected.

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