JP3912312B2 - Shift control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control technique during deceleration of a vehicle.
[0002]
[Prior art]
For example, as described in “NISSAN RE4R01A full range electronic control automatic transmission maintenance manual” (A261C07) issued by Nissan Motor Co., Ltd. in March 1987,
While the driver sets the manual valve to the forward travel range such as the automatic transmission (D) range, the 2-speed engine brake (II) range, and the 1-speed engine brake (I) range by the shift lever, the clutch and brake A state in which a power transmission path (gear stage) of the gear transmission system is determined by selectively fastening a plurality of speed-changing friction elements, etc., and power can be transmitted from the input shaft to the output shaft at the selected speed stage. In addition, a shift to another gear stage is performed by switching the friction element to be fastened.
[0003]
In determining the gear position to be selected here, it is normally described in the above-mentioned document, but at least the vehicle speed VSP (usually, the throttle opening TVO and the throttle opening TVO as shown in FIGS. 4 to 6). Conventionally, the gear to be selected is determined by shift determination based on a shift pattern (solid line is an upshift shift line and a broken line is a downshift shift line) set in advance for each range on the condition of a combination.
[0004]
By the way, when shifting to the shift stage determined in this way, the shift to the determined shift stage is performed by changing the friction element to be fastened by changing the oil path by stroking a plurality of shift valves. For this reason, it is inevitable that a shift response delay will occur between the determination of the shift stage to be selected by shift determination and the actual shift to this shift stage.
Therefore, although the shift determination is made according to the schedule determined by the shift line, the actual shift cannot be performed at the vehicle speed determined by the shift line while relatively fast acceleration or deceleration is being performed. The actual shift does not occur according to the schedule determined by the shift line, and gives the driver a sense of discomfort.
[0005]
This tendency is particularly remarkable during sudden deceleration that can make the time change rate of the vehicle speed large, and the above-mentioned uncomfortable feeling is unacceptable.
Therefore, conventionally, as described in Japanese Patent Application Laid-Open No. 3-103661, when the vehicle is decelerated, a pre-read vehicle speed on the lower vehicle speed side corresponding to the vehicle deceleration is obtained than the actual vehicle speed, and a shift based on the above-described shift line is performed by this pre-read vehicle speed. A shift control technique for making a judgment has been proposed.
According to this shift control, a shift determination is made early in anticipation of a shift response delay at the time of deceleration, and an actual downshift accompanying deceleration is prevented from occurring at a lower vehicle speed than the schedule defined by the shift line. can do.
[0006]
[Problems to be solved by the invention]
By the way, when the engine brake is required, the automatic transmission fastens an engine brake friction element different from the shift friction element so that the engine brake at the selected shift stage can be obtained.
When the engine brake is required, the engine brake friction element is first released and then the gear shift control is performed so that the gear shift is performed as a countermeasure against the shock, but the downshift is no exception.
[0007]
Therefore, if the shift determination based on the look-ahead vehicle speed is performed even during the shift, the downshift accompanying the deceleration is performed at an early stage. Therefore, the shift friction for the downshift is released before the engine brake friction element is released. The elements can be fastened and shift shocks can increase.
[0008]
JP-A-9-1378 6 No. 3 proposes a technique for increasing the engagement vehicle speed of the friction element for engine braking when the vehicle suddenly decelerates, and there is a problem in downshifting based on shift determination based on the look-ahead vehicle speed by applying such conventional technology. In other words, it is conceivable to solve the problem that the downshift gear friction element is fastened before the engine brake friction element is released to increase the shift shock.
[0009]
However, this solution requires correction of the vehicle speed to obtain the look-ahead vehicle speed from the actual vehicle speed when decelerating, and also requires a separate correction operation to increase the engagement vehicle speed of the friction element for engine brake. Double correction is essential. As a result, not only is the control complicated, but there is a problem that the control takes a long time, which is not practical.
[0010]
A first aspect of the present invention is to propose a shift control device for an automatic transmission that solves the problem related to the double correction.
[0011]
A second aspect of the invention according to claim 2 is to propose a shift control device for an automatic transmission which enables the conventional shift determination based on the look-ahead vehicle speed in the first aspect.
[0012]
The third aspect of the present invention is to propose a shift control device for an automatic transmission that eliminates the adverse effect that the pre-read vehicle speed decreases beyond an allowable range.
[0013]
According to a fourth aspect of the present invention, there is provided an automatic transmission capable of preventing over-rotation of the engine when the shift determination based on the pre-reading vehicle speed is performed in a range in which the downshift line is shifted to the high vehicle speed side. An object is to propose a shift control device.
[0014]
[Means for Solving the Problems]
For these purposes, first, a shift control device for an automatic transmission according to the first invention is:
Shifting is performed based on a shift determination based on a preset shift line with at least a vehicle speed as a condition, and the engine brake friction element is appropriately engaged based on a fastening / release determination based on a predetermined engagement region map based on at least the vehicle speed. Used in automatic transmissions,
At the time of deceleration of the vehicle, in a shift control device for an automatic transmission that performs shift determination based on the shift line based on a look-ahead vehicle speed lower than the actual vehicle speed,
It is characterized in that at the time of deceleration in which the shift determination is performed based on the pre-reading vehicle speed, the engagement / release determination of the engine brake friction element is also performed based on the pre-reading vehicle speed.
[0015]
Furthermore, the shift control device for an automatic transmission according to the second invention is the first invention,
The pre-reading vehicle speed is obtained according to vehicle deceleration, and the shift determination is performed based on the pre-reading vehicle speed at the time of normal deceleration when the pre-reading vehicle speed is equal to or higher than a limit vehicle speed obtained by subtracting a set value from the actual vehicle speed. It is characterized by that.
[0016]
A shift control device for an automatic transmission according to a third aspect of the present invention is the second aspect of the invention,
The look-ahead vehicle speed obtained by subtracting a constant vehicle speed smaller than the set value from the actual vehicle speed during sudden deceleration when the look-ahead vehicle speed obtained according to the vehicle deceleration is less than the limit vehicle speed obtained by subtracting the set value from the actual vehicle speed. The allowable lower limit value is configured to be the look-ahead vehicle speed.
[0017]
A shift control device for an automatic transmission according to a fourth invention is any one of the first to third inventions,
Among the ranges, in the range where the downshift line is shifted to the high vehicle speed side, the shift determination is performed based on the actual vehicle speed regardless of the look-ahead vehicle speed even during deceleration.
[0018]
【The invention's effect】
In the first aspect of the invention, the automatic transmission performs a shift based on a shift determination based on a shift line set in advance with at least a vehicle speed as a condition, and an engine by an engagement / release determination based on an engagement region map set in advance with at least a vehicle speed as a condition. Enables engine braking at the selected gear stage by properly engaging the brake friction element.
When the vehicle is decelerating, the shift determination based on the upper shift line is performed based on the look-ahead vehicle speed that is lower than the actual vehicle speed.
[0019]
Therefore, the shift determination is made early in anticipation of a shift response delay at the time of deceleration, and an actual downshift accompanying the deceleration can be prevented from occurring at a lower vehicle speed than the schedule defined by the shift line. .
Therefore, regardless of the vehicle deceleration, the actual shift can always be performed at the vehicle speed according to the schedule defined by the shift line. When the vehicle is decelerated, the actual shift varies according to the degree of the deceleration. The problem of occurring at the vehicle speed can be avoided.
[0020]
In the first aspect of the invention, in particular, at the time of deceleration where the shift determination is performed based on the look-ahead vehicle speed, the engagement / release determination of the engine brake friction element is also performed based on the look-ahead vehicle speed.
For this reason, when the vehicle is decelerated at an early stage according to the pre-reading vehicle speed, the engagement / release determination of the friction element for engine braking is also made at the early stage according to the pre-reading vehicle speed. The engagement of the friction element is performed prior to the release of the friction element for engine brake that should be released for countermeasures to the shift shock at the time of the shift, and the possibility that the shift shock becomes large can be reduced.
In addition, the operation and effect can be achieved only by correcting the vehicle speed to obtain the pre-reading vehicle speed from the actual vehicle speed, and the double correction in the case of applying the above-described conventional technique is unnecessary, and the control can be simplified. The time required for control can be shortened.
[0021]
In the second invention, the pre-read vehicle speed is obtained according to the vehicle deceleration, and at the time of normal deceleration when the pre-read vehicle speed is equal to or higher than the limit vehicle speed obtained by subtracting the set value from the actual vehicle speed, the speed change is performed based on the pre-read vehicle speed. To make a decision,
Regardless of the first invention, the shift determination based on the look-ahead vehicle speed can be performed as usual.
[0022]
In the third aspect of the invention, during a sudden deceleration where the look-ahead vehicle speed obtained according to the vehicle deceleration is less than the limit vehicle speed obtained by subtracting the set value from the actual vehicle speed, a constant vehicle speed smaller than the set value is reduced from the actual vehicle speed. In order to set the pre-reading vehicle speed allowable lower limit obtained by subtraction as the pre-reading vehicle speed,
The pre-reading vehicle speed can be prevented from decreasing beyond the pre-reading vehicle speed allowable lower limit, and the shift determination and the determination of engagement / release of the friction element for engine braking can be prevented too early to prevent the shift from becoming unnatural. .
[0023]
In the fourth invention, in the range in which the downshift line is shifted to the high vehicle speed side in the range, the shift determination is performed based on the actual vehicle speed regardless of the look-ahead vehicle speed even when decelerating.
When the shift determination based on the pre-reading vehicle speed is performed in the range, the engine over-rotation occurs for the following reason. In the fourth aspect of the invention, the engine over-rotation can be prevented.
[0024]
As shown in FIGS. 5 and 6, respectively, in the II range and the I range, as is clear from the comparison with the shift pattern for the D range (including the OD prohibited state) shown in FIG. 2 → 1) Shifting the shift line to a higher vehicle speed side than the corresponding downshift shift line in the D range, and setting the shift pattern so that the engine brake gears (second speed, first speed) are selected as long as possible .
Accordingly, if the downshift (3 → 2, 2 → 1) shift line is shifted to the higher vehicle speed side, the engine speed inevitably increases. Therefore, the downshift of the II range or the I range (3 → 2) , 2 → 1) When shifting the shift line to the high vehicle speed side, it is usual to shift these to the high vehicle speed side as far as possible without causing over-rotation of the engine.
[0025]
For this reason, when the shift determination based on the look-ahead vehicle speed is performed in the II range or the I range, the look-ahead vehicle speed is shifted even though the downshift shift line is shifted to the high vehicle speed side as far as possible without causing the engine to over-rotate. The downshift is executed early (when the vehicle speed is high) by the shift determination by the above, and there is a problem that the possibility of the engine over-rotation increases accordingly.
[0026]
By the way, in the fourth aspect of the invention, particularly in the range where the downshift line is shifted to the high vehicle speed side as in the II range or I range, the shift determination is performed based on the actual vehicle speed regardless of the look-ahead vehicle speed even when decelerating. From that
If a shift determination based on the look-ahead vehicle speed is made during deceleration in the range, as described above, a downshift associated with the deceleration occurs early, and in the range, the downshift shift line is set to a high vehicle speed up to the limit within the range where engine overspeed does not occur. Although shifting to the side is a common practice, the engine over-revolution that you would like to avoid is likely to occur, but in the fourth invention, the shift determination at the time of deceleration in the range is made based on the actual vehicle speed, It is possible to reliably eliminate the excessive rotation of the engine.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an automatic transmission having a speed change control device according to an embodiment of the present invention. Reference numeral 1 denotes an engine, 2 denotes a torque converter, 3 denotes an automatic transmission, and the engine rotation passes through the torque converter 2. It is assumed that the signal is transmitted to the input shaft 4 of the automatic transmission.
[0028]
The automatic transmission 3 is basically the same as that described in the above-mentioned “RE4R01A type automatic transmission maintenance manual” (A261C07) issued by Nissan Motor Co., Ltd.
A front planetary gear set 6 and a rear planetary gear set 7 are mounted on input / output shafts 4 and 5 arranged in a coaxial butting relationship.
[0029]
The forward friction F / C, the high clutch H / C, the band brake B / B, the low one-way clutch L / OWC, the forward one-way clutch F / OWC, and the reverse clutch R / C are provided as friction elements for shifting.
Furthermore, a low reverse brake LR / B provided in parallel to the low one-way clutch L / OWC and an overrun clutch OR / C provided in parallel to the forward one-way clutch F / OWC are provided.
The first forward speed to the fourth forward speed and the reverse gear position can be selected by selectively fastening these friction elements in combinations indicated by circles in FIG. 2B.
[0030]
Note that (２) in FIG. 2B regarding the low reverse brake LR / B and the overrun clutch OR / C indicates when the engine brake is required at the first speed to the third speed (the OD prohibition switch described later by the driver). 13 is used to command the 3rd speed engine brake, and in detail, the 2nd speed engine brake or the 1st speed engine brake is commanded by selecting the II range or I range of the manual valve (not shown) via the shift lever 15 described later. Show that
The low reverse brake LR / B and the overrun clutch OR / C each constitute an engine brake friction element.
Incidentally, the fourth speed is a gear train in which the engine brake works in the case of FIG. 1, and there is no engine brake friction element for the fourth speed.
[0031]
In order to execute the selective operation (fastening) of the friction element, in this embodiment, the shift solenoids A and B and the overrun clutch solenoid 10 are inserted into the control valve 8 of the automatic transmission 3. And
The control valve 8 is further provided with a line pressure solenoid 11 inserted therein in order to control a line pressure that is a hydraulic pressure for fastening the friction elements of the automatic transmission.
The automatic transmission 3 controls the shift solenoids A and B to be a combination of ON (solenoid pressure generation) and OFF (solenoid pressure disappearance) shown in FIG. It is assumed that the friction elements F / C, H / C, and B / B are selectively engaged according to the engagement logic of FIG. 2B so that the fourth speed is selected.
[0032]
The low reverse brake LR / B and the reverse clutch R / C are interlocked with each other when the driver sets the shift lever 15 to the first speed engine brake (I) range position or the reverse travel (R) range position. The hydraulic pressure is supplied from a port of a manual valve (not shown) and is engaged as prescribed. The engine brake at the first speed is applied to the low reverse brake LR / B and an overrun clutch OR / C described later. The reverse gear is selected by engaging the low reverse brake LR / B and the reverse clutch R / C.
Here, it is assumed that the overrun clutch OR / C is engaged when the overrun clutch solenoid 10 is turned off (solenoid pressure disappears) and released when the overrun clutch solenoid 10 is turned on (solenoid pressure is generated).
[0033]
The line pressure solenoid 11 is assumed to increase the line pressure of the automatic transmission by increasing the ON duty.
[0034]
The ON / OFF of solenoids A, B, and 10 and the drive duty of solenoid 11 are determined by controller 14,
A selection range selected by the driver with the shift lever 15 and a signal from the range sensor 16 for detecting a third speed engine brake command from the OD (fourth speed) prohibition switch 13;
A signal from a throttle opening sensor 17 for detecting the throttle opening TVO of the engine 1;
A signal from the vehicle speed sensor 18 for detecting the vehicle speed VSP;
A signal from an acceleration sensor 19 for detecting vehicle acceleration (negative value represents deceleration) G;
A signal from the idle switch that turns ON when the accelerator pedal is released,
A signal from the brake switch 21 that is turned on when the brake pedal is depressed is input.
[0035]
As a supplementary explanation of the shift lever 15 and the range sensor 16, the shift lever 15 is known as described in the above-mentioned document. The parking (P) range position, the reverse travel (R) range position, and the neutral (N) range position are well known. In addition, the forward automatic shift (D) range position, the second speed engine brake (II) range position, and the first speed engine brake (I) range position are arranged in a straight line. It is assumed that when the speed) prohibition switch 13 is turned on, the shift to the 4th speed is prohibited to obtain the engine brake at the 3rd speed.
[0036]
The range sensor 16 outputs a signal indicating where the shift lever 15 is operated in these range positions to the controller 14 and outputs a third speed engine brake command from the OD (fourth speed) prohibition switch 13 to the controller 14. It shall be.
[0037]
During forward travel, the controller 14 executes the control program shown in FIG. 3 based on the above-mentioned input information, and engages the following engine brake friction element (overrun clutch OR / C) when shifting. -Shift control including release control shall be performed.
First, in step 31, based on the signal from the range sensor 16, it is determined whether it is the D range including the OD (fourth speed) prohibition state, the other I range or the II range.
[0038]
In the case of the D range, in step 32, it is determined whether or not the vehicle speed range in which the speed change control during deceleration targeted by the present invention is to be performed, that is, the vehicle speed VSP is a predetermined vehicle speed VSP. _S Then, in step 33, it is determined whether or not other conditions for performing the speed change control during deceleration are satisfied.
Here, the other speed change control conditions for deceleration are that the idle switch 20 is turned on by releasing the accelerator pedal, the brake pedal is depressed and the brake switch 21 is turned on. This means three conditions that the detected vehicle acceleration G is a negative value representing deceleration, and when these three conditions are met, the speed change control during deceleration is performed.
[0039]
If the vehicle speed condition in step 32 is not met or if the three conditions in step 33 are not met, in step 34, the corresponding upshift shift line and downshift shift line in the shift map illustrated in FIG. To determine whether to upshift or downshift from the vehicle speed detection value VSP,
In order that the shift corresponding to the upshift determination and the downshift determination is executed, that is, the engagement / release switching of the friction element for the shift is performed based on the engagement logic of FIG. Based on the logic of 2 (a), solenoids A and B are switched on and off.
However, when an OD (fourth speed) prohibition switch 13 is turned on and a three-speed engine brake command is received, the shift control is performed so that the shift to the fourth speed does not occur.
[0040]
Next, if there is the three-speed engine brake command, in step 35, based on the unillustrated engagement region map of the engine brake friction element (overrun clutch OR / C), the friction element is engaged from the vehicle speed detection value VSP.・ A 3-speed engine brake can be obtained by performing a release determination and controlling the overrun clutch solenoid 10 OFF and ON to properly engage and release the engine brake friction element (overrun clutch OR / C) according to the determination result. To be able to.
[0041]
If it is determined in step 33 that the deceleration speed change control conditions are met, in step 36, the vehicle speed is lower than the vehicle speed detection value VSP that can be obtained in the same manner as described in Japanese Patent Laid-Open No. 3-103661. Low-speed look-ahead vehicle speed VSP according to speed G _INC Check.
This look ahead vehicle speed VSP _INC Is the set value ΔVSP from the vehicle speed detection value VSP. _L Vehicle speed (VSP-ΔVSP) _L ) Or more (VSP−ΔVSP) _L ≦ VSP _INC <VSP), that is, at the time of normal deceleration causing a normal deceleration, in step 37, based on the corresponding upshift shift line and downshift shift line in the shift map illustrated in FIG. 4 for the D range. In addition, look ahead vehicle speed VSP _INC Decide whether to upshift or downshift,
In order that the shift corresponding to the upshift determination and the downshift determination is executed, that is, the engagement / release switching of the friction element for the shift is performed based on the engagement logic of FIG. Based on the logic of 2 (a), solenoids A and B are switched on and off.
[0042]
Next, at step 38, the look-ahead vehicle speed VSP is determined based on an unillustrated engagement region map of the engine brake friction element (overrun clutch OR / C). _INC From the above, the engagement / release determination of the friction element is performed, and the overrun clutch solenoid 10 is controlled to be turned OFF / ON to appropriately engage / release the engine brake friction element (overrun clutch OR / C) according to the determination result. The engine brake of the selected gear stage is obtained.
[0043]
By the way, in this embodiment, when the vehicle is normally decelerated as in step 37, the look-ahead vehicle speed VSP on the lower vehicle speed side corresponding to the vehicle deceleration G than the actual vehicle speed VSP. _INC To make a shift determination based on the shift line,
At the time of the normal deceleration, the shift determination is made early in anticipation of the shift response delay, and the actual downshift accompanying the deceleration can be prevented from occurring at a lower vehicle speed than the schedule determined by the shift line. .
Therefore, regardless of the vehicle deceleration G, the actual shift can always be performed at the vehicle speed according to the schedule defined by the shift line, and various actual shifts can be performed according to the degree of deceleration when the vehicle is decelerated. It is possible to avoid the problem that occurs at a vehicle speed of.
[0044]
In the present embodiment, the pre-reading vehicle speed VSP as described above. _INC In the case of the normal deceleration in which the shift determination is performed by the step S38, the engine brake friction element (overrun clutch OR / C) is determined to be engaged / released as in step 38. _INC To do by
Look-ahead vehicle speed VSP _INC At the time of normal deceleration of the vehicle where the shift determination is made earlier by the determination of the engagement / release of the engine brake friction element, the pre-read vehicle speed VSP _INC Will also be done early,
The fastening of the friction element for shifting for downshift accompanying deceleration is performed prior to the release of the friction element for engine braking (overrun clutch OR / C) that should be released as a countermeasure for shifting shock during the shifting, The possibility that the shift shock becomes large can be reduced.
[0045]
In addition, the operational effect is changed from the actual vehicle speed VSP to the look-ahead vehicle speed VSP. _INC Can be achieved only by correcting the vehicle speed, and the double correction in the case of applying the above-described conventional technique is unnecessary, so that the control can be simplified and the time required for the control can be shortened. .
[0046]
Look ahead vehicle speed VSP in step 36 _INC The determination result is VSP _INC <VSP-ΔVSP _L When the vehicle is suddenly decelerated, if the selected shift speed determined from ON / OFF of the shift solenoids A and B in step 39 is the first speed or the second speed, in step 40, the above ΔVSP is determined from the vehicle speed detection value VSP. _L Constant vehicle speed ΔVSP for first or second speed smaller than _C1 The pre-read vehicle speed allowable lower limit value obtained by subtracting (VSP-ΔVSP) _C1 ) Is the pre-reading vehicle speed, and based on this, the same shift judgment and shift as in step 37 are performed.
[0047]
Next, at step 41, the same look-ahead vehicle speed allowable lower limit value (VSP−ΔVSP) _C1 ) Is used as the pre-reading vehicle speed, and based on this, the engine brake friction element (overrun clutch OR / C) is engaged / released and the engagement / release based on the determination result is performed.
[0048]
When the selected shift speed determined in step 39 is the third speed or the fourth speed, in step 42, the above-described ΔVSP is determined from the vehicle speed detection value VSP. _L Constant vehicle speed ΔVSP for 3rd or 4th speed smaller than _C2 The pre-read vehicle speed allowable lower limit value obtained by subtracting (VSP-ΔVSP) _C2 ) Is the pre-reading vehicle speed, and based on this, the same shift judgment and shift as in step 37 are performed.
Next, at step 43, the same look-ahead vehicle speed allowable lower limit value (VSP−ΔVSP) _C2 ) Is used as the pre-reading vehicle speed, and based on this, the engine brake friction element (overrun clutch OR / C) is engaged / released and the engagement / release based on the determination result is performed.
[0049]
In the present embodiment, the look-ahead vehicle speed VSP _INC Is (VSP-ΔVSP _L In the case of sudden deceleration smaller than), as in steps 40 and 42, the set value ΔVSP is calculated from the actual vehicle speed VSP. _L Constant vehicle speed ΔVSP smaller than _C1 , ΔVSP _C2 Since the pre-read vehicle speed allowable lower limit obtained by subtracting the value is used as the pre-read vehicle speed, it contributes to the shift determination and the determination of engagement / release of the friction element for engine brake.
The pre-reading vehicle speed will not drop below the pre-reading vehicle speed allowable lower limit value, and the shift determination and the determination of engagement / release of the friction element for engine braking will be made too early to prevent the shift from becoming unnatural. Can do.
[0050]
In addition, the above constant vehicle speed ΔVSP _C1 , ΔVSP _C2 Is different for each selected gear stage (first speed and second speed, and third speed and fourth speed), and the look-ahead vehicle speed allowable lower limit value can be set to a suitable value for each gear stage. Even in the stage, the above-described effects can be achieved reliably.
[0051]
Look ahead vehicle speed VSP in step 36 _INC The determination result is VSP _INC If ≧ VSP, the vehicle is traveling at a constant speed or acceleration and is not subject to the speed change control during deceleration, so the control is naturally advanced to steps 34 and 35.
[0052]
In step 31, when the II range and the I range are selected in which the downshift line is shifted to the higher vehicle speed side than the downshift line for the D range in FIG. 4 as indicated by broken lines in FIGS. In the case of determination, the control is advanced to Steps 34 and 35, regardless of whether or not the vehicle is decelerating. _INC Instead of the above, based on the vehicle speed detection value VSP, a shift determination based on the shift patterns of FIGS. 5 and 6 and an engagement / release determination of the engine brake friction element are performed.
[0053]
Here, the look-ahead vehicle speed VSP at the time of deceleration in the II range and I range in which the downshift line is shifted to the high vehicle speed side. _INC As described above, when the shift determination is performed, the downshift accompanying the deceleration occurs early, and in this range, it is common to shift the downshift line to the high vehicle speed side as far as possible without causing the engine to over-rotate. For this reason, it is inevitable that the engine will over-rotate easily.
[0054]
Therefore, in the present embodiment, when performing the shift determination based on the shift patterns of FIGS. 5 and 6 in the II range and the I range, the look-ahead vehicle speed VSP is determined even when decelerating. _INC Regardless of this, since the shift determination is performed based on the actual vehicle speed VSP, the downshift accompanying the deceleration can be prevented from occurring at an early stage, and therefore, the over-rotation of the engine that is absolutely desired to be avoided can be surely eliminated. it can.
[Brief description of the drawings]
FIG. 1 is a shift control system diagram of an automatic transmission including a shift control device according to an embodiment of the present invention.
FIG. 2 is an operation logic diagram of the automatic transmission,
(A) is a drawing showing the relationship between ON and OFF of the shift solenoid and the selected gear stage;
(B) is drawing which shows the relationship between the selection gear stage and fastening of a friction element.
FIG. 3 is a flowchart showing shift pressure control executed by a controller in the automatic transmission.
FIG. 4 is a shift pattern diagram illustrating an upshift shift line and a downshift shift line for a D range.
FIG. 5 is a shift pattern diagram illustrating an upshift shift line and a downshift shift line for the II range.
FIG. 6 is a shift pattern diagram illustrating an upshift shift line and a downshift shift line for the I range.
[Explanation of symbols]
1 engine
2 Torque converter
3 Automatic transmission
4 Input shaft
5 Output shaft
6 Front planetary gear set
7 Rear planetary gear set
8 Control valve
A Shift solenoid
B Shift solenoid
10 Overrun clutch solenoid
11 Line pressure solenoid
13 OD prohibit switch
14 Controller
15 Shift lever
16 Range sensor
17 Throttle opening sensor
18 Vehicle speed sensor
19 Accelerometer
20 Idle switch
21 Brake switch
F / C forward clutch (friction element for shifting)
H / C high clutch (friction element for shifting)
B / B band brake (friction element for shifting)
LR / B low reverse brake
OR / C overrun clutch (friction element for engine brake)
L / OWC Rowan Way Clutch
F / OWC forward one-way clutch

Claims (4)

Shifting is performed based on a shift determination based on a preset shift line with at least a vehicle speed as a condition, and the engine brake friction element is appropriately engaged based on a fastening / release determination based on a predetermined engagement region map based on at least the vehicle speed. Used in automatic transmissions,
At the time of deceleration of the vehicle, in a shift control device for an automatic transmission that performs shift determination based on the shift line based on a look-ahead vehicle speed lower than the actual vehicle speed,
A shift control apparatus for an automatic transmission, wherein at the time of deceleration in which the shift determination is performed based on the pre-reading vehicle speed, the engagement / release determination of the engine brake friction element is also performed based on the pre-reading vehicle speed. 2. The pre-reading vehicle speed according to claim 1, wherein the pre-reading vehicle speed is determined according to vehicle deceleration, and the normal-deceleration vehicle speed is equal to or greater than a limit vehicle speed obtained by subtracting a set value from an actual vehicle speed. A shift control apparatus for an automatic transmission, characterized in that the determination is made. 3. The vehicle speed according to claim 2, wherein the look-ahead vehicle speed obtained according to the vehicle deceleration is less than a limit vehicle speed obtained by subtracting the set value from the actual vehicle speed, and a constant vehicle speed smaller than the set value is subtracted from the actual vehicle speed. A shift control apparatus for an automatic transmission, characterized in that the pre-read vehicle speed allowable lower limit value obtained in this way is set as the pre-read vehicle speed. The shift determination according to any one of claims 1 to 3, wherein, in the range in which the downshift line is shifted to a higher vehicle speed side, the shift determination is performed based on an actual vehicle speed regardless of the look-ahead vehicle speed even when decelerating. A shift control device for an automatic transmission, characterized in that it is configured.

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