JPH09264417A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently shift a gear to a re-acceleration status without any need of waiting for a drop in travel speed by finding a correction value corresponding to the acceleration of an engine speed, and correcting an overrun judgement speed at a higher level for demanding a shift-down operation. SOLUTION: A transmission control unit makes judgement as to whether shift control should be made or not, upon the occurrence of a vehicular shift demand. Also, the magnitude of the acceleration of an engine speed is judged with a means 38 on the basis of the engine speed, and the set value of the magnitude is stored as an overrun judgement speed in a means 46. Furthermore, when the engine acceleration speed drops to a positive value equal to or below the prescribed level, depending on the judgement value thereof, with an accelerator opening totally closed in the gear set condition where a clutch is engaged and a transmission is at a forward travel gear, a climbing state is judged with a means 44 and a correction value is determined. The overrun judgement speed is thereby corrected and set at a higher level. According to this construction, a gear is efficiently shifted to a re-acceleration status without waiting for a drop in travel speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle automatic transmission.

[0002]

2. Description of the Related Art In a vehicle automatic transmission equipped with means for controlling a gear change to a target stage when a vehicle upshift request and a vehicle downshift request are generated, while ensuring re-acceleration performance when traveling uphill, In order to properly prevent engine or transmission overruns, a means for calculating the engine speed after a gear shift based on the gear ratio at the requested gear and the vehicle speed, and a gear change when the calculated value is higher than the overrun judgment speed. Means for prohibiting the vehicle, a means for judging an uphill when the deceleration state (running acceleration is negative) of the vehicle continues for a predetermined time when the accelerator opening is equal to or greater than a predetermined value (criterion criterion for fully opening the accelerator), and an overrun judgment rotation at the time of the judgment. There is a device provided with a means for correcting the speed to be higher by a predetermined value (Japanese Patent Application No. 5-194829).

[0003]

However, in this prior art example, when the running acceleration of the vehicle is 0 or repeats positive and negative, the vehicle is not judged to be uphill despite the accelerator being fully closed. There is a problem that you can not move to.

An object of the present invention is to effectively solve such a problem.

[0005]

In the first aspect of the invention, as shown in FIG. 7, an automatic transmission apparatus for a vehicle comprising means a for generating a shift request of the vehicle and means b for controlling a gear change to the required stage. , A means g for calculating the engine rotation speed after the gear shift from the gear ratio of the gear shift request stage and the vehicle speed, a means j for inhibiting the gear change when the calculated value is higher than the overrun determination rotation speed, and an accelerator opening. Means for determining an uphill from the degree and the acceleration of the vehicle speed or the engine rotation speed, a means i for obtaining a correction value according to the vehicle speed or the acceleration of the engine rotation speed at the time of the uphill determination, and a downshift request by adding the correction value. Means k for correcting the overrun determination rotational speed at a high time is provided.

According to a second aspect of the invention, as means for obtaining the correction value of the overrun determination rotational speed in the first aspect of the invention, means for setting a correction value according to the vehicle speed or the acceleration of the engine rotational speed for each gear stage of the transmission, A means for determining a correction value from the correction value selected based on the shift-down request stage in accordance with the acceleration of the vehicle speed or the engine rotation speed is provided.

According to a third invention, in the first invention, means n for prohibiting an upshift at the time of judging an uphill is provided.

[0008]

According to the first aspect of the invention, the rotational speed for determining the overrun at the time of climbing is corrected to a higher value according to the acceleration of the vehicle speed or the engine rotational speed. The steeper the slope of the uphill, the greater the degree of deceleration accompanying the shift, but the acceleration of the vehicle speed or the engine speed reflects the slope condition of the uphill, so even if the uphill judgment range is expanded to a positive acceleration, It is possible to avoid overrun caused by downshift. As a result, the downshift is performed earlier according to the climbing condition, so that it is possible to efficiently shift to the reacceleration condition without waiting for the decrease in the vehicle speed.

According to the second aspect of the present invention, it is possible to obtain the overrun determination rotational speed that accurately reflects the traveling condition when climbing a slope, including the gear ratio.

According to the third aspect of the invention, even if a shift-up request is issued, the shift-up at the time of uphill determination is prohibited. Therefore, the driving force becomes insufficient after the shift-up and the vehicle speed decreases, and the shift-down occurs. It is possible to avoid so-called shift busy, in which gear changes are repeatedly repeated toward the.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 3 is a clutch actuator for engaging and disengaging a clutch, 1 is a gear shift actuator for driving a gear shift mechanism of a transmission, and a throttle actuator for driving an accelerator lever of an engine fuel injection pump ( (Not shown).

As means for detecting the operating state necessary for controlling these actuators, an accelerator sensor 12 for detecting a depression angle of an accelerator pedal 11, an engine rotation sensor 7 for detecting an engine rotation speed, and a stroke position of a clutch are detected. A clutch stroke sensor 4, a gear position sensor 2 for detecting a shift position of a transmission, a vehicle speed sensor 5 for detecting a rotation speed of a main shaft of the transmission, and a gear rotation for detecting a rotation speed of a main gear idling on the main shaft. A sensor 6 is provided.

To switch between manual control and automatic control of the clutch, pedal switches 14a and 14b for detecting the initial position and the operating position of the clutch pedal 13 are provided. In the cab, the transmission shift lever device 15
In addition to the (shifter), a monitor 16 for displaying the shift position of the transmission and the like is provided. As the shifter 15, a simple h-type operation pattern having 5 positions of upshift, downshift, hold (holds the current shift stage), reverse, and neutral is adopted.

The engine control unit 20 and the transmission control unit 21 control the drive of the actuator based on these output signals.
When a shift request is made, it is determined whether or not a gear change to the target gear is possible, and a series of shift control is executed when the gear change is permitted. First, the fuel injection pump is returned to the fully opened position of the accelerator and the clutch is disengaged at the same time, while the transmission gear is shifted to the required shift stage. Then, when the gear set of the transmission is completed, the clutch is connected and the fuel injection pump is returned to the accelerator opening degree according to the depression angle of the accelerator pedal.

The transmission control unit 21 has a function of determining whether or not the shift control is possible when a shift request of the vehicle is generated in order to prevent overrun of the engine or the like. FIG. 2 shows a functional block configuration of the control system. Means 38 for determining the magnitude of the rotational acceleration of the engine from the rotational speed of the engine, and a set value defined on the basis of a flat road as the overrun determination rotational speed. When the accelerator opening is fully closed when the clutch is connected and the transmission is in the forward gear set state, the determination value becomes less than or equal to a positive predetermined value according to the determination value of the rotational acceleration of the engine. If it goes down, the climbing condition becomes 2
It is provided with a means 44 for judging the stage and a means 45 for fixing the correction value according to the judging stage of the climbing state and correcting the overrun judgment rotational speed to a higher degree accordingly.

A means 39 for calculating the engine rotational speed after shifting from the vehicle speed and the gear ratio of the target stage of the shift request,
Means 36 for determining a downshift based on the current gear position of the transmission and the target gear of the gearshift request, means 37 for similarly determining an upshift based on the current gear position and the target gear of the gearshift request, and a gearshift during the downshift determination. A means for prohibiting downshifting to a target stage when the subsequent engine rotation speed is higher than the overrun rotation speed (that is, permitting the shift control only when the engine rotation speed after the shift is less than or equal to the overrun determination rotation speed) 40, and means 41 for prohibiting upshifting to the target stage when the uphill state is determined during upshift determination.

Reference numeral 31 is a means for converting the detection signal of the engine rotation sensor 7 into engine rotation speed, 32 is a means for judging the accelerator opening of the engine from the detection signal of the accelerator sensor 12, and 33 is a detection signal of the gear position sensor 2. Means for determining the current gear position of the transmission; 34 for converting the detection signal of the vehicle speed sensor 5 into vehicle speed; 35 for deciding a required gear shift target stage from a shift lever 15 and a shift request based on a shift map; Reference numeral 48 is a means for retrieving a shift speed corresponding to the vehicle speed and the accelerator opening from the shift map and generating a shift request to that shift speed when a shift is required, and 43 is a clutch disconnection from the detection signal of the clutch stroke sensor 4. Represents a means for determining the state.

Here, as shown in FIG. 3, the uphill judging means 44 reduces the engine rotational acceleration ALPH when the accelerator opening degree ACC reaches the full load state while the transmission is in the forward gear stage and the clutch is engaged. The positive set value SN is compared (step 1 to step 4).
Then, when ALPH ≦ SN, Timer1 is activated, and when that state continues for a predetermined time TS1 (for example, 1 second), the uphill determination flag UPHILL1 is set to 1 (steps 5 to 7).

Further, when ALPH is reduced to <0, Tim
er2 is started, and in that state TS2 (for example,
When the elapsed time of 1 second) is counted, the uphill determination flag UP
HILL2 is set to 1 (step 8 to step 1)
1). At least one of step 1 to step 4 is NO
If, then in step 12, Timer1 = 0 and Timer2 = 0, UPHILL1 = 0 and UP
Keep HILL2 = 0. If NO in step 8, in step 13, Timer2 = 0, UPH
Maintain ILL2 = 0.

The overrun determination rotation speed correction means 45 unconditionally sets a default value OVRD as the overrun determination rotation speed OVRLMT (step 1). When the uphill determination flag UPHILL is 1, the correction value UPH1 is added to the default value OVRD as the overrun determination rotation speed OVRLMT (steps 2 and 3). In addition, the uphill determination flag UPH
When ILL2 = 1, overrun determination rotation speed OVR
Correction value UPH2 as LMT default value OVRD
Is added to (step 4, step 5). The correction value UPH1 and the correction value UPH1 are set to satisfy the relation of UPH1 <UPH2.

FIG. 5 is a diagram for explaining the gear shift possibility determination performed by the overrun determination means 40 and the shift up possibility determination means 41. When the shift request downshift is determined, the gear ratio and the vehicle speed of the target gear are determined. Then, the engine speed PNE after shifting is calculated (step 1, step 2). Then, the engine speed PNE after the shift is compared with the overrun determination speed OVRLMT at that time,
When PNE ≧ OVRLMT, the downshift control to the target stage is prohibited, while when PNE <OVRLMT, the downshift control to the target stage is permitted (step 2).
~ Step 5). When it is determined that the shift request is upshifting, the state of the uphill determination flag UPHILL1 is confirmed. When UPHILL1 = 1, the upshift control to the target gear is prohibited, while when UPHILL1 = 1, the target gear is shifted to the target gear. Permission is given to the shift-up control of (step 6 to step 9).

With such a configuration, the region for judging the uphill state is the positive predetermined region (A) of the rotational acceleration ALPH of the engine.
LPH ≤ SN), and in that region, the permissible rotational speed for downshifting (overrun determination rotational speed OVRLM depending on the magnitude of engine rotational acceleration ALPH)
T) is increased in two steps. For this reason, when the accelerator pedal is depressed during traveling on an uphill slope, downshifting is allowed earlier, so that it is possible to quickly shift to the re-acceleration state without reducing the vehicle speed so much. Further, since the overrun determination rotation speed is corrected to a high value in anticipation of the deceleration amount due to the shift during climbing, even if downshifting is allowed from a high rotation speed, overrun does not occur.

Even if a shift-up request is issued, the shift-up is prohibited in the uphill judgment area. Therefore, the driving force after the shift-up is insufficient, the vehicle speed decreases, and the driver is busy again for the shift-down. Is repeated,
So-called shift busy can be avoided.

As the overrun determination rotation speed correction means 45, a data map in which the correction value UPH continuously changes in accordance with the rotation acceleration of the engine as shown in FIG. The correction value U corresponding to the rotational acceleration ALPH of the engine from the data map corresponding to the target stage of the shift-down request without going through 44.
The PH may be searched. In that case, a simplification of the control program is obtained. Further, since the correction value UPH is provided for each shift speed, the overrun determination rotational speed OVR that accurately reflects the traveling condition when climbing the slope including the gear ratio between the shift speeds.
LMT is obtained.

[0025]

According to the first aspect of the invention, in the automatic transmission apparatus for a vehicle, which is provided with a means for generating a shift request of the vehicle and a means for controlling the gear change to the required gear, From the means for calculating the engine speed after shifting from the vehicle speed, the means for prohibiting gear change when this calculated value is higher than the overrun determination speed, and the accelerator opening and the acceleration of the vehicle speed or engine speed. A means for determining an uphill, a means for obtaining a correction value according to the acceleration of the vehicle speed or the engine rotation speed at the time of the uphill determination, and a means for adding the correction value and correcting a higher overrun determination rotation speed when a downshift request is made. Since it was set up,
Since the overrun determination rotation speed is corrected according to the vehicle speed or the engine speed acceleration that reflects the grade condition of the uphill slope, even if the uphill judgment range is expanded to a positive acceleration,
It is possible to avoid overrun caused by downshift. As a result, the downshift is performed earlier according to the climbing condition, so that it is possible to efficiently shift to the reacceleration condition without waiting for the decrease in the vehicle speed.

According to the second invention, as means for obtaining the correction value of the overrun determination rotational speed in the first invention,
A means for setting a correction value according to the vehicle speed or the acceleration of the engine rotation speed for each gear position of the transmission, and a correction value according to the acceleration of the vehicle speed or the engine rotation speed from the correction value selected based on the required shift down stage. Since the means for determining is included, it is possible to obtain the overrun determination rotation speed that accurately reflects the traveling condition when climbing the hill, including the gear ratio.

According to the third aspect of the present invention, in the first aspect of the present invention, the means for prohibiting the shift-up at the time of uphill determination is provided, so that the shift busy after the shift due to the careless shift-up can be prevented.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of the present invention.

FIG. 2 is a functional block diagram similarly showing a part of a control system.

FIG. 3 is a flow chart for explaining control contents in the same manner.

FIG. 4 is a flowchart for explaining control contents.

FIG. 5 is a flowchart similarly illustrating the control content.

FIG. 6 is an explanatory diagram of an overrun determination correction value representing another embodiment.

FIG. 7 is a diagram corresponding to claims of the present invention.

[Explanation of symbols]

 1 Gear shift actuator 2 Gear position sensor 3 Clutch actuator 4 Clutch stroke sensor 5 Vehicle speed sensor 6 Gear rotation sensor 7 Engine rotation sensor 12 Accelerator sensor 14a, 14b Clutch switch 15 Shifter 20 Engine control unit 21 Transmission control unit 21

Claims (3)

[Claims] 1. An automatic transmission apparatus for a vehicle, comprising: a means for generating a shift request of a vehicle; and a means for controlling a gear change to the required stage, in an engine rotation after shifting from a gear ratio and a vehicle speed at the shift required stage. A means for calculating the speed, a means for prohibiting a gear change when the calculated value is higher than the overrun determination rotation speed, a means for determining the uphill slope from the accelerator opening and the acceleration of the vehicle speed or the engine rotation speed, and A vehicle provided with means for obtaining a correction value according to the acceleration of the vehicle speed or engine rotation speed during uphill judgment, and means for adding the correction value and correcting a higher overrun judgment rotation speed when a downshift is requested. Automatic transmission. 2. A means for obtaining a correction value for an overrun determination rotation speed, which is selected on the basis of a means for setting a correction value according to an acceleration of a vehicle speed or an engine rotation speed for each gear position of a transmission and a shift down request gear. The automatic transmission according to claim 1, further comprising means for determining a correction value from the correction value according to the acceleration of the vehicle speed or the engine rotation speed. 3. The automatic transmission according to claim 1, further comprising means for prohibiting an upshift when an uphill judgment is made.