JP3478418B2 - Automatic transmission control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic shift control device, and more particularly, to a device for automatically downshifting and operating the engine brake in a traveling condition where the engine brake is required.

[0002]

2. Description of the Related Art Conventionally, as an automatic shift control device for detecting a running state requiring engine braking and automatically downshifting, for example, Japanese Patent Laid-Open No. 1-279914.
The one described in Japanese Patent Publication No. 4 is known. This conventional automatic shift control device has a traveling state determination means for determining the traveling state of the vehicle based on signals from the accelerator depression detection means and the vehicle speed detection means. By increasing the number, it is determined that the vehicle is traveling downhill and the automatic transmission is downshifted. Therefore, when traveling downhill, downshifting is automatically performed, which eliminates the need for the driver to operate the select lever.

[0003]

However, in the above-mentioned conventional automatic shift control device, the engine braking is applied independently of the driver's intention, which may cause a feeling of strangeness in the shift. there were. by the way,
As a means for the driver to obtain engine braking without feeling uncomfortable, a so-called D range in which automatic gear shifting is performed, for example, 2
It is common to perform a downshift to a low-speed gear position by performing an operation to select a low-speed range such as the high-speed range.In such a case, the gear position selected by the shift control corresponding to the selected range , That is,
Sufficient engine braking may not be obtained at gear positions based on the selected range shift schedule.

Further, in the above-mentioned conventional automatic shift control device, the downshift is performed independently of the driver's intention during the engine brake control. Therefore, the downshift to a certain gear position has already been performed by the engine brake control. At times, when the driver feels insufficient braking force and operates the select lever, he or she may select the current gear position.In such a case, the downshift will not be performed even if the select operation is performed, There is a problem that the driver feels uncomfortable.

The present invention has been made in view of the above-mentioned conventional problems, and it is a first object of the present invention to ensure that engine braking can be obtained without causing the driver to feel uncomfortable.
The second purpose is to ensure that the engine brake can be obtained without a sense of discomfort when a selection operation to a low speed gear position is performed during engine brake control.

[0006]

In order to achieve the first object of the present invention, therefore, as shown in the claim correspondence diagram of FIG. 1, the vehicle travel including the vehicle speed and the throttle opening is performed. A traveling state detecting means a for detecting parameters relating to the state, and included in the traveling state detecting means a,
The optimum gear position of the automatic transmission c is determined based on the signals from the select detection means b for detecting the operation related to the driver's select operation and the traveling state detection means a, and the automatic transmission c is set to the optimum gear position. The shift control means d for shifting gears to the gear shift control means d, and the select operation is performed only when the engine brake select operation for obtaining the engine brake is detected based on the signal from the select detection means b. After the gear shift is performed, it is determined whether the running state is the engine braking required state requiring the engine braking, and when it is determined that the engine braking is required, the gear position at least one step lower than the gear position at that time is determined. An engine brake control unit e that performs engine brake control for downshifting to the position is installed. It was.

Further, the engine brake control section e is
In the engine brake control, it is configured to repeatedly perform the determination as to whether or not the engine is in a required state and the downshift processing at the time of determining the required state of the engine brake, even after the shift control to the gear position one step lower. br /> it was. Further, the engine brake control unit e determines whether the select range changes, the throttle opening changes, or the vehicle speed becomes lower than a predetermined value after downshifting by engine brake control. or, if it is detected that the ignition key to OFF operation, and configured to release the engine brake control.

[0008]

The engine brake select operation is, for example, an operation of selecting a low range by a select lever (claim 2 ) or an operation of an overdrive prohibition switch (claim 3 ).

Further, the determination of the engine brake required state by the engine brake control unit is made based on the acceleration of the vehicle (claim 4).

[0011]

In the device according to the first aspect, after the driver performs the engine brake select operation which is the select operation for obtaining the engine brake (this engine brake select operation is, for example, the one described in claim 3 ). Only when the low speed range is selected by the select lever as described or the operation of the overdrive prohibition switch as described in claim 4 ) is performed.
However, shift control corresponding to this operation, usually downshifting, is performed, and engine braking is obtained. As described above, the gear shift is performed according to the engine brake select operation to obtain the engine brake, so that the driver can obtain the engine brake without feeling uncomfortable.

After the gear shift is performed according to the engine brake select operation, the engine brake control section e determines whether or not the traveling state is the engine brake required state, and the engine brake required state is determined. When it is determined, the gear position is downshifted to the gear position one step lower than the gear position at that time. Therefore, if sufficient engine braking cannot be obtained by the gear shift corresponding to the first engine brake select operation, then a downshift is performed by the engine brake control of the engine brake control unit e to ensure that the engine brake is applied. can get.

[0013] Even after the downshift is made by the engine brake control of this engine braking control unit e, not enough engine braking is obtained, the engine brake control unit e is, running state engine brake required state If it is determined that there is, a downshift is further performed, and engine braking can be reliably obtained. Further, the determination of the engine braking required state is performed by, for example, claim 4.
As described in, it can be determined by the acceleration of the vehicle, for example, when downshifting or when the acceleration of the vehicle increases even though the throttle opening is small,
It is determined that the engine brake is required.

Further, et emissions Gin brake control unit e is, after downshift by the engine brake control, it is detected that the driver has another selection, there is no intention by the driver to obtain an engine brake (high speed side The range is selected), or conversely, when it is determined that a stronger engine brake is to be obtained (the range on the low speed side is selected), or it is determined that the driver intends to accelerate due to a change in the throttle opening. If, or if it is determined that the vehicle speed is lower than a predetermined value and the vehicle is in a traveling state where engine braking is unnecessary, or if the ignition key is O
When FF is determined and it is determined that the vehicle is not running, the engine brake control is released.

[0015]

[0016]

[0017]

[0018]

Embodiments of the present invention will be described with reference to the drawings. Figure 2 is a schematic diagram showing an automatic transmission control apparatus of the first embodiment corresponds to the invention 2 according to claim 1 rabbi, engine E, a torque converter TC and the auxiliary transmission CG
Is connected to the automatic transmission AT. The automatic transmission AT is provided with a control valve CV that operates by hydraulic pressure to shift the auxiliary transmission CG. It should be noted that the auxiliary transmission CG is configured to shift gears to the forward first speed to fourth speed (fourth speed is overdrive).

The control valve CV is not shown in conjunction with the operation of a valve (not shown) that is interlocked with the operation of the select lever SL provided near the driver's seat and by the control of the control unit (shift control means) CU. It is configured to perform a gear shift operation by driving a solenoid valve. Also, the select lever SL
Has three range positions on the forward side, the D range, the second speed range, and the first speed range. Normally, when the D range is selected, it is based on the relationship between the throttle opening and the vehicle speed. According to the shift schedule (see FIG. 3), the gears are shifted in the range from the first speed to the fourth speed, and in the second speed range or the first speed range, the gear positions of the respective ranges are basically changed. Based on the set shift schedule (for the shift schedule of the second speed range, see FIG. 4), the shift can be performed in the range of the first speed to the third speed. The shift schedule for the second speed range basically selects the second speed, but is set so that the first speed or the third speed may be selected depending on the relationship between the throttle opening and the vehicle speed.

The control unit CU has a vehicle speed sensor 1 for detecting a vehicle speed, a throttle opening sensor 2 for detecting a throttle opening, and a select detecting means for detecting a select position of the select lever SL as a traveling state detecting means. The inhibitor switch 3 as the above, the overdrive prohibiting switch 4 for outputting a signal for prohibiting the shift to the overdrive, and the ignition switch 5 for operating the driving / stopping of the engine E are connected.

Next, the control flow of the control unit CU will be described with reference to the flowchart of FIG.

In step S1, it is determined whether or not the engine brake select operation is performed. If YES, the process proceeds to step S2, and if NO, step S1 is repeated. In addition,
In this embodiment, the engine brake select operation is
It indicates that the forward range other than the D range is selectively operated by the select lever SL, which is detected by the signal from the inhibitor switch 3. By the way, since this step is basically to determine that the driver has performed an operation to obtain engine braking, it is necessary to determine whether or not the overdrive prohibition switch 4 has been operated. Alternatively, it may be determined whether or not any one of the selection of the forward drive range other than the D range and the operation of the overdrive prohibition switch 4 is performed.

In step S2, it is determined whether or not an engine brake flag F _{EB, which} will be described later, is 1, and if YES, the process proceeds to step S4, and if NO, the process proceeds to step S3.

In step S3, the shift control is performed based on the shift schedule of the selected range (for example, when the second speed range is selected, the shift schedule shown in FIG. 4). That is, based on this shift schedule, the optimum gear position G _P is selected according to the detected throttle opening TH and the vehicle speed V, and the control valve C sends a signal for shifting to this gear position G _P.
Output to V.

In step S4, it is determined based on the signal from the throttle opening sensor 2 whether the throttle valve is fully closed. If YES, the process proceeds to step S5, and NO.
Then, the process returns to step S1. The full closing of the throttle valve may be determined based on a signal from the throttle valve full closing switch which is closed by closing the throttle valve.

In step S5, it is determined whether or not the vehicle is in an accelerating state based on the rate of change of the vehicle speed V obtained from the signal from the vehicle speed sensor 1. If YES, the process proceeds to step S6 and N
If O, the process returns to step S1. That is, this step S5
Then, the final judgment is made as to whether or not the engine braking is required. In step S4, the throttle opening TH
However, when the vehicle is accelerating, it is determined that the engine braking is required, and the process proceeds to step S6.

In step S6, engine brake control is performed. This engine brake control is a control for shifting to a gear position one step lower than the gear position G _NOW at that time ( _GP = G _NOW -1), and in this step S6, the engine brake flag F _{EB is} further added. Is set to 1. That is, the engine brake flag F _EB is
This is a flag indicating that engine brake control is being performed so that the gear position is lower than the gear position G _P based on the shift schedule.

In step S7, the inhibitor switch 3
Based on the input from, it is determined whether or not the selection range by the select lever SL has changed, and if YES, step S
The process proceeds to step S11, and if NO, the process proceeds to step S8.

In step S8, it is determined whether or not the throttle opening TH has changed, that is, whether or not the throttle opening TH has changed from the fully closed state. If YES, the process proceeds to step S11, and NO.
Then, the process proceeds to step S9.

In step S9, it is determined whether or not the vehicle speed V is lower than a predetermined value V _{0. If} YES, the process proceeds to step S11, and if NO, the process proceeds to step S10. The predetermined value V ₀ is a value for determining whether the vehicle is stopped or in a state close to it, and is 0 or 10 km / h.
It is a small value below.

In step S10, it is determined whether or not the ignition key switch 5 is OFF. If YES, the process proceeds to step S11, and if NO, the one-open flow ends.

In step S11, the engine brake flag F _{EB is set} to 0 in order to cancel the engine brake control.

Next, the operation of the first embodiment will be described. While driving, the driver operates the select lever SL to set D
When a forward range other than the range is selected, first, the gear is shifted to the optimum gear position based on the shift schedule of the selected range (steps S1 → S2 → S3).

When the forward range is selected in this way, and when the intention is to obtain engine braking, the driver normally does not press the accelerator at all, and the throttle opening TH at this time is It is 0 (fully closed).
If sufficient engine braking is not obtained due to the shift corresponding to the selection of the forward range, the vehicle is accelerated without being decelerated.

Therefore, when the vehicle is accelerating despite the throttle opening TH being 0, the control unit CU performs engine braking control to lower the gear position G _P by one step (step S4 →
S5 → S6). For example, if sufficient deceleration is not achieved even if the second speed range is selected and the downshift is performed to the second speed gear position, the gear position is automatically changed to the first speed gear position.

With such engine braking control, even if the gear position G _P is lowered by one step and the acceleration is still achieved, the gear position G _P is further lowered by one step (steps S1 → S2 → S4 → S5 →
Flow of S6). For example, when the 2nd speed range is selected, the 3rd speed is determined to be optimal based on the shift schedule, and the shift control is performed, whereas the engine brake control is performed and the 2nd speed is downshifted. If the vehicle is not sufficiently decelerated, it is downshifted to the first speed.

Thereafter, whether the select lever SL is operated, the throttle opening is changed, the vehicle speed is reduced to a predetermined vehicle speed, or the ignition key switch 5 is turned on.
If it becomes FF, the engine brake flag F _EB becomes 0.
Is changed to, the engine brake control is ended, and the shift control based on the shift schedule is performed. That is, when the select lever SL is operated to select the D range, the shift control based on the D range shift schedule is performed. If the range of the select lever SL has not been changed, the flow of steps S1 → S2 → S3 is performed, and the shift control based on the shift schedule of the selected range is performed.

As described above, in this embodiment, the engine brake control is performed only when the driver selects the forward range other than the D range, so that the driver can obtain the engine brake. Although there is no intention to do so, the downshift for obtaining the engine brake is not performed, and the effect that the driver does not feel uncomfortable is obtained. Further, not only is the shift (manual shift) based on the shift schedule of the range selected by the driver's operation of the select lever SL performed, but in this state, when sufficient engine braking cannot be obtained, automatic Downshift is performed to ensure that sufficient engine braking is obtained.

That is, in the first embodiment, there is an effect that the engine brake can be surely obtained without the driver feeling uncomfortable.

Next, the second invention corresponding to the invention of claim 5
Examples will be described. In describing the second embodiment, only the differences from the first embodiment will be described.

This second embodiment is different from the first embodiment in the control contents of the control unit CU, and its control flow will be described with reference to the flowchart of FIG.

In step S21, the select lever SL
Is determined to be in the D range, the process proceeds to step S22 if YES, to step S29 if NO.

In step S22, the upshift prohibition flag F _{UP is set} to 0, and the optimum gear position G _P based on the shift schedule in the D range is selected.

In step S23, it is determined whether or not the gear position selected in step S22 is the fourth speed. If YES, the process proceeds to step 24, and if NO, step S2.
Go to 8.

In step S24, the necessity of engine braking is determined from the throttle opening deceleration TH _DOWN and the vehicle speed V based on the characteristics shown in FIG.

In step S25, the result of the determination in step S24 determines whether or not engine braking is required. If YES, the process proceeds to step S26, and if NO, step S26.
Proceed to 27.

In step S26, the third gear is selected as the optimum gear position G _P , and the engine brake flag F _EB is set to 1.

In step S27, the engine brake flag F _EB is set to 0.

In step S28, a control signal for shifting to the optimum gear position G _P is output.

At step S29, the select lever SL
Is determined to be in the second speed range. If YES, the process proceeds to step S30, and if NO, the process proceeds to step S39.

In step S30, the optimum gear position G is set based on the shift schedule for the second speed range.
Select _P.

In step S31, it is determined whether or not the engine brake flag F _EB is 1, and if YES, step S31
32. If NO, the process proceeds to step S35.

In step S32, the optimum gear position G _P determined in step S30 is compared with the current gear position G _NOW, and if the current gear position is on the higher speed side, the process proceeds to step S33, otherwise, That is, if the selected optimum gear position G _P is equal to or higher than the current gear position G _NOW , the process proceeds to step S34.

[0054] In step S33, gear position to determine the gear position G _P optimal at step S30 G _P
The processing to be left as is is performed, and the process proceeds to step S27.

[0055] At step S34, performs a process for determining the gear position G _P optimal one step lower gear position than the present gear position G _{NO W,} and performs processing for the up-shift inhibiting flag F _UP 1 Step S2
Proceed to 7.

[0056] In step S35, similarly to step S32, is compared with the optimum gear position G _P and the current gear position G _{the NOW} determined in step S30, the direction of the current gear position G _{the NOW} if low-speed Step S
If not, that is, if the determined optimum gear position G _P is the same as the current gear position G _NOW or on the low speed side, the process proceeds to step S38.

In step S36, it is determined whether or not the upshift prohibition flag F _UP is 1, and if YES, the process proceeds to step S37, and if NO, the process proceeds to step S38.

[0058] At step S37, the process proceeds to step S28 performs a process for determining the gear position G _P of ideal current gear position G _{NO W.}

[0059] At step S38, the gear position to determine the gear position G _P optimal at step S30 G _P
The processing that remains is performed and the process proceeds to step S28.

In step S39, the upshift prohibition flag F _UP and the engine brake flag F _EB are set to 0, and the optimum gear position G is set according to the shift schedule of the range in which the select lever SL is arranged.
_The process of determining _P is performed, and the process proceeds to step S28.

Next, the operation of the second embodiment will be described.

When the optimum gear position G _P determined based on the shift schedule of the D range is the 4th speed while the select lever SL is operated to the D range and the vehicle is running, the throttle opening deceleration TH _DOWN and the vehicle speed V The necessity of engine brake control is determined from. That is, as the deceleration TH _DOWN is higher and the vehicle speed V is lower, it is determined that the engine brake control is necessary, and when it is necessary, the downshift is performed to the third speed.

While the engine brake control is being performed, the driver wants to obtain more braking force by the engine brake and operates the select lever SL in two ranges. , The optimal gear position G _P determined based on the two range shift schedule according to the throttle opening) is lower than the current gear position G _NOW (2nd speed or 1st speed).
If it is determined that is appropriate, the gear position is changed to the gear position G _P based on this shift schedule (steps S31 → S32 → S33 in the flowchart), while the two ranges are set according to the running state at this time. optimum gear position G _P which is determined based on the shift schedule, when it is determined that the same gear position as the current gear position G _{the nOW} (3 speed), rather than the current gear position G _{the nOW} optimum gear position G _P It is determined that the gear position is one step lower (step S3 in the flowchart).
1 → S32 → S34 flow) Shift to that gear position.

When the downshift is performed by one gear lower than the gear position based on the second gear shift schedule, the upshift prohibition flag F _{UP is set} to 1 (step S34). In the range shift schedule, upshifting to the 3rd speed is not performed even if the appropriate running state is reached, and the current gear position is maintained (step S in the flowchart).
32 → S35 → S36 → S37) to prevent an unexpected upshift against the driver's intention of downshifting. The upshift prohibition flag F _UP is changed to 0 when a range other than the second speed range is selected (steps S21 → S22, steps S29 → S39) to enable upshifting.

As described above, in the automatic shift control device of the second embodiment, when this device performs engine brake control and is already downshifting to the third speed,
When the driver performs an operation of selecting a low speed range (2nd speed range), the downshift is always performed according to the 2nd speed range shift schedule even in a traveling state in which the gear position G _{NOW is} not changed. With this configuration, the downshift is reliably performed without the inconvenience that the downshift is not performed even though the driver manually performed the downshift operation to obtain engine braking, and the driver feels uncomfortable. There is no effect.

Although the embodiment has been described above, the specific configuration is not limited to this embodiment, and the present invention includes a design change and the like within a range not departing from the gist of the invention.

For example, in the embodiment, the automatic transmission AT having the fourth forward speed is shown as an example, but the present invention is not limited to this, and the present invention can be applied to various gears such as the fifth forward speed. Therefore, when applied to an automatic transmission of fifth forward speed, in step S23 of the second embodiment, is the optimum gear position G _P either fourth speed or fifth speed? , And again,
In step S29, it is determined whether or not the vehicle is in the third speed range, and the same flow as that of steps S29 to S39 of the second embodiment is added to the step to be performed when NO is determined in step S29. To do.

In the second embodiment, step S3
When the optimum gear position G _P is processed to be a gear position one step lower in step 4, a control may be added to prohibit this downshift in a traveling state in which the engine E may overrev.

[0069]

As described above, in the device according to the first aspect of the present invention, the engine brake control is performed after the driver performs the engine brake select operation and the gear shift according to the select operation is performed. When it is determined that the driving state is an engine braking required state, the driver performs engine braking by down-shifting to a gear position at least one step lower than the gear position at that time. Only when there is an intention to obtain, the shift is performed to obtain the engine brake, the driver does not feel discomfort,
In addition, if sufficient engine braking cannot be obtained due to this shift, the engine can be downshifted automatically to ensure engine braking, that is, the driver can feel the sense of comfort without feeling discomfort. The effect that the engine brake is obtained is obtained.

[0070] In addition, when the engine brake control according et emissions Jin brake control unit, since the running state is to perform the downshift until no is determined that the engine brake required conditions, the effect of reliably engine braking is obtained by al Play.

[0071] Further, after performing the down-shift by e emissions Gin brake control, or the select range is changed, or whether the throttle opening is changed, or whether the vehicle speed is smaller than a predetermined value, or the ignition When it is detected that the key has been turned off, the engine brake control unit is configured to release the engine brake control. Therefore, the engine brake control can be released appropriately in accordance with the driver's intention and running condition. The effect that it can be obtained is obtained.

[0072]

Further, in the apparatus according to claims 2 and 3 , the engine brake select operation is detected by selecting the low range by the select lever or operating the overdrive prohibition switch. The effect that it can be used is obtained.

Further, in the apparatus according to the fourth aspect , when the engine braking is required is determined based on the acceleration of the vehicle, the existing vehicle speed sensor or acceleration sensor can be used to make an accurate determination. it can.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing an automatic shift control device of the invention.

FIG. 2 is a schematic diagram showing an automatic shift control device according to a first embodiment of the present invention.

FIG. 3 is a flowchart showing a control flow of a control unit of the first embodiment.

FIG. 4 is a flowchart showing a control flow of a control unit of the automatic shift control device according to the second embodiment of the present invention.

FIG. 5 is a characteristic diagram of necessity determination of automatic engine braking of the second embodiment device.

FIG. 6 is a flowchart showing a control flow of a control unit of the second embodiment device.

FIG. 7 is a characteristic diagram of necessity of engine braking in the second embodiment device.

[Explanation of symbols]

a Running state detection means b Automatic transmission c Shift control means d Select detection means

Continuation of the front page (56) Reference JP-A-5-231522 (JP, A) JP-A-62-246650 (JP, A) JP-A-6-185602 (JP, A) JP-A 1-266027 (JP , A) Actually open 6-8814 (JP, U) Actually open 62-114250 (JP, U) Actually open 4-50755 (JP, U) Actually open 63-25862 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] 1. A running state detecting means for detecting parameters relating to a running state of a vehicle including a vehicle speed and a throttle opening, and a select detecting means included in the running state detecting means for detecting an operation relating to a select operation by a driver. A shift control means for determining an optimum gear position of the automatic transmission based on a signal from the traveling state detection means and shifting the automatic transmission to the optimum gear position; Only when an engine brake select operation that attempts to obtain engine brake is detected based on a signal from the detection means, the engine brake is required when the driving condition is engine brake after the gear shift corresponding to the select operation is performed. If it is determined that the engine braking is required, the gear at that time is determined. Downshift to a gear position that is at least one step below the position, and then determine whether engine braking is required.
Every time, downshift at the time of judging the engine braking required state
Engine braking configured to repeat processing
Control and downshift by engine brake control
The select range changes, or
Or the vehicle speed is lower than the specified value.
Becomes smaller, or the ignition key is set to OF
When it is detected that the F operation has been performed, the engine
An automatic shift control device comprising: an engine brake control unit configured to release rake control . 2. The engine brake select operation is
The automatic shift control device according to claim 1, wherein the automatic shift control device is an operation for selecting a low speed range with a select lever . 3. The engine brake select operation is
Characterized by the operation of the overdrive prohibition switch
The automatic shift control device according to claim 1 or 2 . 4. The engine brake control unit is configured to
The required condition of the engine brake is determined based on the acceleration of the vehicle.
It is constituted so that it may be set.
The automatic shift control device according to item 3 .