JP4910298B2 - Shift control device for automatic transmission - Google Patents

Description

  The present invention relates to a shift control device for an automatic transmission, and in particular, it is possible to change the speed change means by selecting an optimum shift stage so that the driver does not feel uncomfortable even when the road surface condition changes. The present invention relates to a shift control device for an automatic transmission capable of improving the performance.

  In an automatic transmission mounted on a vehicle, a shift means having a plurality of shift speeds is provided. In order to shift the speed change means, for example, as shown in FIG. 9, a shift speed selected from a vehicle speed and a throttle opening is set. A shift control device having a preset shift map is provided. The shift control device of the automatic transmission shifts by engaging or releasing the friction engagement element with a shift solenoid or the like so as to be a shift stage selected based on the shift map from the throttle opening and the vehicle speed at that time. The gears of the means are shifted up and down to change the speed.

  Here, the shift up / down according to the road surface condition will be explained. As shown in FIG. 9, when the throttle opening and the vehicle speed are point A while the vehicle is traveling on the winding road, the shift stage is the third speed. When the accelerator pedal is returned in front of the curve, the throttle opening and the vehicle speed move to the point B, a shift up to the fourth speed occurs, and the engine braking force becomes insufficient. After that, if the vehicle goes off the curve and the driver tries to accelerate again, the driving force is insufficient, so the driver steps on the accelerator pedal, the throttle opening and the vehicle speed move to point C, and shifts to the third speed. Down occurs.

  Such shift-up / shift-down of the automatic transmission is not intended by the driver. The automatic transmission should inherently generate a suitable engine braking force toward the curve, and then shift to a gear position that provides the driving force required by the driver after exiting the curve.

Some shift control devices for such an automatic transmission prohibit upshifting for a certain period (predetermined time) when the rate of change in accelerator opening falls below a negative threshold value (set value). . As a result, when the driver suddenly returns the accelerator pedal before the curve, the shift control device of this automatic transmission is prohibited from shifting up for a predetermined time, so that an appropriate engine braking force is obtained before the curve. Thus, there is an effect that an appropriate driving force can be obtained when the vehicle escapes from the curve.
Patent Registration No. 3037369 Patent registration No. 3122083

Further, the shift control device for an automatic transmission has a shift map in which a shift-up is performed at each vehicle speed in a shift map set in advance by a vehicle speed and an accelerator opening, and a shift-up timing is used. In some cases, an actual shift-up in response to a shift-up request is determined based on a shift-up timing at the time of non-downhill travel, and the shift-up at the time of downhill travel is executed without causing the driver to feel uncomfortable.
Patent Registration No. 3535697

  However, the winding road includes a relatively flat winding road and a steep winding road. As described in Patent Document 1 and Patent Document 2, the same set value of the accelerator opening change rate and the upshift are respectively used. There was a limit to the improvement of drivability when the predetermined time for prohibiting the operation was set.

  Further, as in Patent Document 3, the accelerator opening in the shift map set in advance by the vehicle speed and the accelerator opening is used as a shift-up timing, and the up-shifting during downhill driving is performed based on the up-shifting timing during non-downhill driving. When determining the value, there is a limit to improvement in drivability because the rate of change in the accelerator opening is not taken into consideration.

The present invention provides an automatic transmission provided with an automatic transmission having a shift means that is shifted up and down so as to become a shift stage selected based on a preset shift map, and capable of detecting the accelerator opening. An accelerator opening change rate calculating means for calculating an accelerator opening change rate from the accelerator opening detected by the accelerator opening detecting means is provided, and an accelerator calculated by the accelerator opening change rate calculating means is provided. When the change rate of the opening is lower than the set value, the road surface gradient state can be detected in the shift control device of the automatic transmission provided with the shift-up prohibition means for prohibiting the shift-up of the shift means for the idle elapsed determination time. A road surface gradient detection means, a road surface friction coefficient detection means capable of detecting a road surface friction coefficient, and a road surface gradient detected by the road surface gradient detection means. A setting value changing means for changing the value of the set value based on the state and the road surface friction coefficient detected by the road surface friction coefficient detecting means, and a state in which the upshifting of the speed change means is prohibited by the upshift inhibiting means When the preset idle elapsed determination time has elapsed, or when the state where the accelerator pedal is depressed continues for longer than the accelerator depression elapsed determination time, the shift-up prohibiting means is released , and The set value changing means sets the set value on the uphill road to a value larger than the set value on the flat road, and sets the idle elapsed determination time on the uphill road to a value longer than the idle elapsed determination time on the flat road. set, the accelerator depression elapsed determination time that is set to a value longer than the determination time in the flat road determination time in uphill And butterflies.

The shift control device for an automatic transmission according to the present invention can shift the shift means by selecting an optimal shift stage so that the driver does not feel uncomfortable even when the road surface condition changes. During traveling, it is possible to improve the drivability by increasing the set value of the accelerator opening change rate and increasing the predetermined time for prohibiting the shift-up as compared with traveling on a flat road.

The shift control device for an automatic transmission according to the present invention can select the optimum shift stage so that the driver does not feel uncomfortable even when the road surface condition changes, thereby shifting the shifting means and improving the drivability. It can be made to.
Embodiments of the present invention will be described below with reference to the drawings.

  1 to 9 show an embodiment of the present invention. In FIG. 7, 2 is an engine mounted on a vehicle (not shown), and 4 is an automatic transmission. The automatic transmission 4 includes a torque converter 6 and an auxiliary transmission mechanism 8 that is a transmission means. The auxiliary transmission mechanism 8 has a plurality of shift stages including planetary gears (not shown) and the like, and is shifted up and down by the engagement / release of the friction engagement element 10 including a clutch, a brake, and the like, and is shifted.

  A valve body 12 is provided below the automatic transmission 4. The valve body 12 is provided with first and second solenoids 14 and 16 for shifting of a shift valve (not shown) for supplying an operating pressure to the friction engagement element 10 of the auxiliary transmission mechanism 8 to switch the engagement state. Yes.

  The first and second solenoids 14 and 16 for shifting are connected to the control unit 20 of the shift control device 18 of the automatic transmission 4. The control unit 20 includes an engine rotation sensor 22 that detects the rotation speed of the engine 2, a throttle opening sensor (throttle opening detection means) 24 that detects a throttle opening of a throttle valve (not shown) of the engine 2, and A vehicle speed sensor (vehicle speed detection means) 26 for detecting the vehicle speed from the rotational speed of the output shaft of the automatic transmission 4 and a shift position switch 28 for detecting the shift position of a shift lever (not shown) of the automatic transmission 4 are connected. Yes. The throttle opening sensor 24 also functions as an accelerator opening detecting means for detecting the accelerator opening of an accelerator pedal (not shown) that opens and closes the throttle valve.

  The control unit 20 of the shift control device 18 includes a shift map 30 (see FIG. 9) in which shift speeds selected from the vehicle speed and the throttle opening are set in advance, and is provided with shift speed calculation means 32, and the accelerator opening change rate. A calculation means 34, a shift-up prohibiting means 36, a road surface gradient detecting means 38, a road surface friction coefficient detecting means 40, a set value changing means 42, and a gear position command means 44 are provided.

  The shift speed calculating means 32 calculates a shift speed based on the shift map shown in FIG. 9 from the throttle opening detected by the throttle opening sensor 24 and the vehicle speed detected by the vehicle speed sensor 26.

  The accelerator opening change rate calculating means 34 calculates the accelerator opening change rate from the throttle opening (accelerator opening) detected by the throttle opening sensor 24. The accelerator opening change rate is obtained by calculating the change amount of the accelerator opening per unit time.

  When the accelerator opening change rate calculated by the accelerator opening change rate calculating unit 34 is lower than the set value, the shift up prohibiting unit 36 shifts up the auxiliary transmission mechanism 8 that is a shifting unit only for a predetermined time. Ban.

  The road surface gradient detecting means 38 detects a road surface gradient state. In this embodiment, a gradient sensor 46 that detects a vehicle front-rear direction inclination is connected to the control unit 20, and a road surface gradient state is detected by a detection signal from the gradient sensor 46. In addition, you may use the other well-known estimation method for the gradient state of a road surface.

  The road surface friction coefficient detecting means 40 detects a road surface friction coefficient. In this embodiment, an anti-lock break system (ABS) 48 mounted on the vehicle is connected to the control unit 20, and a road surface friction coefficient is calculated from an operation signal of the ABS 48. The road surface friction coefficient can also be calculated from the speed difference between the driving wheel and the driven wheel.

  The set value changing means 42 is a set value for determining the accelerator opening change rate based on the road surface gradient state detected by the road surface gradient detecting means 38 and the road surface friction coefficient detected by the road surface friction coefficient detecting means 40. Change the value.

  The shift speed command means 44 outputs a command signal to the shift first and second solenoids 14 and 16 and supplies it to the friction engagement element 10 so that the shift speed selected by the shift speed calculation means 32 is obtained. Control the working pressure. The friction engagement element 10 is engaged or released by the operating pressure, and shifts up / down the shift speed of the auxiliary transmission mechanism 8 to change the speed.

  The shift-up prohibiting means 36 differs between a predetermined time when the accelerator opening detected by the throttle opening sensor 24 serving as an accelerator opening detecting means is fully closed and a predetermined time when the accelerator opening is not fully closed. Set to value.

  The set value changing means 42 sets the set value on the uphill road to a value larger than the set value on the flat road, and sets the predetermined time on the uphill road to a value longer than the predetermined time on the flat road. The set value changing means 42 sets the set value on the low friction road to a value smaller than the set value on the flat road, and sets the predetermined time on the low friction road to a value shorter than the predetermined time on the flat road. Set.

  In this way, the shift control device 18 of the automatic transmission 4 shifts based on the shift map from the throttle opening detected by the throttle opening sensor 24 and the vehicle speed detected by the vehicle speed sensor 26, as shown in FIG. A shift speed calculating means 32 for calculating the speed is provided, and an accelerator opening change rate calculating means 34 for calculating an accelerator opening change rate from the throttle opening (accelerator opening) detected by the throttle opening sensor 24 is provided. When the accelerator opening change rate calculated by the opening change rate calculating means 34 is lower than the set value, a shift up prohibiting means 36 for prohibiting the upshifting of the auxiliary transmission mechanism 8 for a predetermined time is provided, and a road surface gradient detecting means 38 is provided. Based on the road surface gradient state detected by the road surface friction coefficient and the road surface friction coefficient detection means 40, the accelerator opening change rate is calculated. A set value changing means 42 for changing the set value to be set is provided, and a command signal is outputted to the first and second solenoids 14 and 16 for shifting so as to be the speed selected by the speed calculating means 32. Shift speed command means 44 for controlling the operating pressure supplied to the friction engagement element 10 is provided.

  Next, the operation of the shift control device 18 of the automatic transmission 4 will be described.

  With reference to the flowchart shown in FIG. When the control is started (100), the shift control device 18 of the automatic transmission 4 calculates the accelerator opening change rate (102).

  The accelerator opening change rate is obtained as a change amount per unit time (for example, for 20 msec) of the accelerator opening AP. Here, it is assumed that the rate of change in the accelerator opening is ΔAP, a negative value is obtained when the accelerator pedal is operated in the return direction, and a positive value is obtained when the accelerator pedal is operated in the depression direction.

  Next, the road surface gradient state is detected (104), the road surface friction coefficient is detected (106), and it is determined whether there is an uphill road (108). If this determination (108) is YES on an uphill road, the threshold value (set value) of the accelerator opening change rate AP is set to ΔAP1 (110).

  If the determination (108) is NO on the uphill road, it is determined whether or not the road surface friction coefficient is a low friction road (low μ road) (112). If this determination (112) is YES on the low friction road, the threshold value (set value) of the accelerator opening change rate AP is set to ΔAP2 (114).

  When the determination (112) is NO instead of the low friction road, the threshold value (set value) of the accelerator opening change rate AP is set to ΔAP0 (116).

  The accelerator opening change rate ΔAP calculated from the accelerator opening AP (102) and the change rate threshold values (ΔAP0, Δ determined by the judgment of the uphill road and the low friction road (108, 112)) (AP1 or ΔAP2) and a determination is made as to whether or not the accelerator opening change rate ΔAP is less than the change rate threshold (118).

  If this determination (118) is YES when the accelerator opening change rate ΔAP <the change rate threshold value, it is determined that the accelerator pedal has been suddenly returned, and upshifting is prohibited (120), and the termination is processed ( 122). If this determination (118) is NO instead of the accelerator opening change rate ΔAP <the change rate threshold value, the process ends (122).

  Next, the shift-up prohibition release determination will be described with reference to the flowchart of FIG. When the control is started (200), the shift control device 18 of the automatic transmission 4 determines whether or not upshifting is prohibited (202).

  If this determination (202) is NO during the shift-up prohibition but is NO, it means that the shift-up prohibition has not been determined in the flowchart of FIG. (226).

  If this determination (202) is YES while upshifting is prohibited, it is determined whether there is an uphill road (204). If this determination (204) is YES on the uphill road, the determination time (predetermined time) of the idle elapsed time is T11 (206), and the determination time (predetermined time) of the accelerator depression elapsed time is T21 (208). .

  If the determination (204) is NO on the uphill road, it is determined whether or not the road surface friction coefficient is a low friction road (low μ road) (210). When this determination (210) is YES on the low friction road, the determination time (predetermined time) of the idle elapsed time is T12 (212), and the determination time (predetermined time) of the accelerator depression elapsed time is T22 (214). .

  If the determination (210) is not a low friction road but NO, the determination time (predetermined time) of the idle elapsed time is T10 (216), and the determination time (predetermined time) of the accelerator depression elapsed time is T20 (218) ).

  The idle elapsed time is compared with the determination time (any of T10, T11, T12) determined in the judgment of the uphill road and the low friction road (204, 210), and the idle elapsed time is equal to or longer than the determination time (predetermined time). It is determined whether or not (220).

  If this determination (220) is YES when the elapsed idle time is equal to or greater than the determination time, the shift-up prohibition is canceled (224), and the process ends (226).

  When this determination (220) is NO with the elapsed idle time <the determination time, the determination time (T20, T21, T22) determined by the accelerator depression elapsed time and the determination of the uphill road and the low friction road (204, 210). (Either), and it is determined whether the accelerator depression elapsed time is equal to or longer than the determination time (predetermined time) (222).

  If this determination (222) is YES with the accelerator depression elapsed time ≧ determination time YES, the shift-up prohibition is canceled (224), and the process is terminated (226). If this determination (222) is NO when the accelerator depression elapsed time <determination time, the process ends (226) and the shift-up prohibition is continued.

  Next, the determination of the gear position will be described with reference to the flowchart of FIG. When the control is started (300), the shift control device 18 of the automatic transmission 4 stores the current shift speed (GP) in GPOLD (302), and determines the shift speed according to the shift map from the throttle opening and the vehicle speed ( 304) and input to the gear stage GP. For example, as shown in FIG. 9, the shift map is set in advance according to the throttle opening and the vehicle speed, thereby determining the shift stage.

  Following the determination of the gear position (304), it is determined whether an upshift has occurred (306). The occurrence of the shift up is performed by comparing GP and GPOLD. If GP> GPOLD, it is determined that the shift up has occurred.

  If no shift up has occurred in the determination (306), the process ends (312). If a shift up occurs in the determination (306) and the answer is YES, it is determined whether the shift up is prohibited (308).

  If this determination (308) is NO and no upshifting is prohibited, the process ends (312). If this determination (308) is YES while upshifting is prohibited, the shift stage GP = GPOLD is returned to the previous shift stage (310), the upshifting is prohibited, and the process ends (312).

  The above processing will be described according to the time charts of FIGS.

  FIG. 4 is a time chart showing the case of traveling on a flat road. If the accelerator pedal is suddenly returned at time t0 while traveling on a flat road, the value of the accelerator opening change rate changes in a negative direction. Here, when the rate of change of the accelerator opening is lower than the threshold value, a shift up to the fourth speed is normally generated, but the shift up is prohibited and the third speed is maintained. After that, when the accelerator pedal is depressed for a determination time T20 from the time t1, the shift-up prohibition is canceled and the upshifting is performed to four stations.

  FIG. 5 is a time chart showing a case where the vehicle is traveling on an uphill road. During traveling on an uphill road, as in FIG. 4, the accelerator pedal change rate becomes lower than the threshold at time t <b> 0 due to the rapid return of the accelerator pedal, and the upshift is prohibited, and the third speed is maintained. However, when the accelerator pedal is depressed for a determination time T21 longer than T20 from time t1, the upshift prohibition is canceled and the upshift to the fourth speed is performed.

  FIG. 6 is a time chart showing the case of traveling on a low friction road. While traveling on a low friction road, the accelerator pedal was suddenly returned at time t0. However, since the rate of change in the accelerator opening degree during traveling on the low friction road did not fall below the threshold value, the shift up to the fourth speed was performed. .

  As a result, the shift control device 18 of the automatic transmission 4 tends to be prohibited from being shifted up on an uphill road, lengthens the time for prohibiting the shift up, and conversely is difficult to prohibit the shift up on a low friction road. The driving time can be shortened, and drivability can be improved in response to various road surface conditions.

  As described above, the shift control device 18 of the automatic transmission 4 prohibits the shifting means from shifting up for the determination time (predetermined time) when the accelerator opening change rate is lower than the threshold value (set value). By changing the threshold value of the accelerator opening change rate based on the road surface gradient state and the road surface friction coefficient, the optimum gear position is set so that the driver does not feel uncomfortable even if the road surface condition changes. Can be selected to change the speed of the speed change means, and the drivability can be improved.

  Further, the shift-up prohibiting means 36 determines a determination time (predetermined time) when the accelerator opening detected by the throttle opening sensor 24 as the accelerator opening detection means is fully closed and a determination time when the accelerator opening is not fully closed. By setting the (predetermined time) to a different value, even if the road surface condition changes, it is possible to select the optimum gear position that does not cause the driver to feel uncomfortable and to change the speed change means, It is possible to improve drivability.

  Further, the set value changing means 42 sets the threshold value (setting value) on the uphill road to a value larger than the threshold value (setting value) on the flat road, and the determination time (predetermined time) on the uphill road Is set to a value that is longer than the judgment time (predetermined time) on a flat road, and it is easier to execute upshift-inhibiting control than a flat road on an uphill road, and the time during which it is executed is also set longer than that on a flat road. Therefore, even when climbing a mountain road (winding road), it is possible to carry out smooth shift control in accordance with the driver's request.

  Furthermore, the setting value changing means 42 sets the threshold value (setting value) on the low friction road to a value smaller than the threshold value (setting value) on the flat road, and the determination time ( By setting the (predetermined time) to a value shorter than the judgment time (predetermined time) on the flat road, it is difficult to execute the control for prohibiting the up-shifting on the flat road and the time during which the control is performed is flat. Since it is set shorter than the road, it is possible to implement smooth shift control in accordance with the driver's request (to increase vehicle stability).

  In the above-described embodiment, the threshold value (set value) of the accelerator opening change rate for prohibiting the shift-up of the speed change means is changed based on the road surface gradient state and the road surface friction coefficient. When the road surface condition changes by changing not only the road surface friction coefficient but also the steering operation state, brake pedal depression state, etc., the vehicle will move back and forth, act, and move up and down (behavior) ) Can be selected to change the speed change means by selecting an optimal shift speed so that the driver does not feel uncomfortable, and drivability can be improved.

  The shift control device for an automatic transmission according to the present invention is capable of shifting the shift means by selecting an optimal shift stage so that the driver does not feel uncomfortable even when the road surface condition changes. The present invention can be applied not only to an automatic variable transmission including a transmission unit having a plurality of shift stages but also to an automatic transmission including a transmission unit that can change a transmission ratio steplessly such as CVT.

It is a flowchart of a shift-up prohibition showing an embodiment of a shift control device of an automatic transmission. It is a flowchart of cancellation | release of upshift prohibition. It is a flowchart of the determination of a gear stage. It is a time chart during driving on a flat road. It is a time chart during driving on an uphill road. It is a time chart during driving on a low friction road. It is a schematic block diagram of a transmission control apparatus. It is a control block diagram of a transmission control apparatus. It is a figure which shows the shift map by throttle opening and a vehicle speed.

Explanation of symbols

2 Engine 4 Automatic Transmission 6 Torque Converter 8 Auxiliary Transmission Mechanism 10 Friction Engagement Element 12 Valve Body 14 Shifting First Solenoid 16 Shifting Second Solenoid 18 Shift Control Device 20 Control Unit 22 Engine Rotation Sensor 24 Throttle Opening Sensor 26 Vehicle speed sensor 28 Shift position switch 30 Shift map 32 Shift speed calculating means 34 Accelerator opening change rate calculating means 36 Shift up prohibiting means 38 Road surface gradient detecting means 40 Road surface friction coefficient detecting means 42 Setting value changing means 44 Shift speed command means 46 Gradient Sensor 48 ABS

Claims (1)

An automatic transmission is provided with a shift means that is shifted up and down so as to be a shift stage selected based on a preset shift map,
An accelerator opening detection means capable of detecting the accelerator opening is provided,
An accelerator opening change rate calculating means for calculating the accelerator opening change rate from the accelerator opening detected by the accelerator opening detecting means is provided,
When the accelerator opening change rate calculated by the accelerator opening change rate calculating means is lower than a set value, an automatic transmission provided with a shift up prohibiting means for prohibiting the shift means from shifting up for an idle elapsed determination time In the shift control device of
Provide road surface gradient detection means capable of detecting the road surface gradient state,
A road surface friction coefficient detecting means capable of detecting a road surface friction coefficient is provided,
Setting value changing means for changing the value of the setting value based on the road surface gradient state detected by the road surface gradient detecting means and the road surface friction coefficient detected by the road surface friction coefficient detecting means;
In a state where the upshifting of the speed change unit is prohibited by the upshift prohibiting unit, when a preset idle elapsed determination time has elapsed, or when the accelerator pedal is depressed, the state continues longer than the accelerator depression elapsed determination time In such a case, the shift-up prohibiting means is canceled and
The set value changing means sets the set value on the uphill road to a value larger than the set value on the flat road, and sets the idle elapsed determination time on the uphill road longer than the idle elapsed determination time on the flat road. Set to
The accelerator depression elapsed determination time is set such that the determination time on an uphill road is set to a value longer than the determination time on a flat road .

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