JP3201152B2 - Control device for automatic transmission for vehicle on uphill road - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for an automatic transmission for a vehicle on an uphill or downhill road.

[0002]

2. Description of the Related Art In an automatic transmission for a vehicle, generally,
A shift map is provided which uses vehicle speed and engine load (throttle opening and the like) as parameters, and information on the vehicle speed and engine load at that time during running is applied to this shift map to determine a shift speed to be selected. .

[0003] However, since this shift map is created on the basis of a general level terrain running state, for example, when traveling on a downhill road or an uphill road, it does not always provide an optimum shift speed.

In view of such circumstances, for example, Japanese Patent Publication No. Sho 59
Japanese Patent No. 8698 proposes a technique in which shift maps are separately provided according to the state of a traveling road such as for traveling on a flat road or traveling on an uphill road, and these are appropriately switched and used.

In Japanese Patent Publication No. 59-8698, a reference vehicle acceleration (expected value of running acceleration) on a flat road is obtained in advance by using a throttle opening, a vehicle speed, and the like as parameters. Also disclosed is a technique for comparing the calculated actual vehicle acceleration with the calculated actual vehicle acceleration to determine that the vehicle is traveling on a downhill if the actual acceleration is larger than a reference acceleration by a predetermined value or more, and that the vehicle is traveling on an uphill if the actual acceleration is smaller than the reference acceleration. Have been.

[0006] When it is determined that the vehicle is traveling on an uphill or downhill, generally, in order to further enhance the power performance on an uphill or on a downhill, it is necessary to reduce the speed of the low speed gear to make the engine brake more effective. Control to maintain the side is performed.

By the way, the road gradient is, for example, when shifting from an uphill road to a downhill road, specifically, from an uphill road to a flat road,
Next, it changes to a downhill road. Therefore, the uphill control may shift from the uphill control to the normal control and then to the downhill control in accordance with the change of the road surface gradient. The shift may be performed every time the control is shifted, and the busyshift (frequent shift) may occur. is there.

Therefore, for example, in Japanese Unexamined Patent Application Publication Nos. 5-71623 and 71625, Japanese Patent Publication No. 61-48019, etc., a fixed delay time is provided when canceling uphill control, and cancellation is performed after the delay time has elapsed. Accordingly, a technique for preventing a busy shift has been proposed.

[0009]

When executing uphill control, for example, regarding the threshold value of the road surface gradient, if the threshold value is set too small, the vehicle enters the uphill / downhill control even on a road surface having a slight gradient, so that the busy shift is performed. It is easy to occur. Therefore, from the viewpoint of preventing a busy shift, the threshold value of the road surface gradient for determining whether or not to enter the uphill / downhill control needs to be set to a relatively large value.

However, if the threshold value of the road surface gradient for entering the uphill control is set to a large value, for example, in a situation where the uphill road and the downhill road are frequently repeated, such as a mountainous road, for example, the downhill road is used. When shifting to a slope, even if a delay time is provided, ascending control is performed with the elapse of the delay time unless the actual road slope on the descending slope is higher than the threshold value of the (largely set) road slope. Since the control is released and returned to the normal control, a shift occurs in many cases. Then, when the gradient of the downhill road becomes steeper and exceeds the threshold value thereafter, the shift from the normal control to the downhill control is performed at that point, so that the gearshift occurs again.

Although such a problem can be solved to some extent (for the problem of the busy shift) by increasing the set delay time, in a situation where the ascending and descending slope control is to be truly released. However, there is a problem that the release is delayed.

The present invention has been made in view of such a conventional problem, and does not unnecessarily lengthen the delay time, and furthermore, the downhill control from the uphill control or the uphill control from the downhill control is continued. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle on an uphill or downhill road, which can surely reduce a busy shift even in a running state that occurs.

[0013]

According to the present invention, FIG.
(A) has a means for judging whether or not the vehicle is traveling on an uphill or downhill, and when it is determined that the vehicle is traveling on an uphill or downhill, a gear suitable for the uphill or downhill is obtained. In the control device for an automatic transmission for a vehicle on an uphill road configured to release the uphill control after a predetermined delay time has elapsed when the uphill control is released, the present time is within the delay time. Means for determining whether or not the threshold value of the road slope as a criterion for the determination of the downhill road is set to be smaller during the delay time than during the delay time. As a result, the above object has been achieved.

Further, as shown in FIG. 1B, the gist is provided with a means for determining whether or not the vehicle is traveling on an uphill or downhill. In addition to setting the appropriate gear,
Means for determining whether or not a current time point is within the delay time, in a control device for an automatic transmission for a vehicle on an uphill road configured to release the downhill control after a predetermined delay time has elapsed. Means for setting the threshold value of the road surface gradient as a criterion in the determination of the uphill road to be smaller when the vehicle is during the delay time than when the vehicle is not during the delay time. It has been achieved.

[0015]

In the present invention, a delay time is set when canceling the uphill control, and if the current time corresponds to the delay time, the delay time is set during the delay time in the uphill control. When there is a downhill road, on the other hand, when it is during the delay time in downhill control, when it is during an uphill road, the threshold value of the reference road surface gradient is compared with when it is not during the delay time. Set to be smaller.

As a result, when the vehicle shifts from an uphill road to a downhill road, even if the vehicle cannot completely move downhill during the delay time, the road surface gradient is smaller than the threshold value which is set smaller. As long as it is larger, it is possible to directly shift from the uphill control to the downhill control without returning to the normal control. As a result, the shift speed can be maintained at the low speed, and the occurrence of the busy shift can be prevented.

Similarly, even when shifting from a downhill road to an uphill road, the threshold value for judging an uphill road is set to a low value during the delay time of the downhill road. Even if it is not possible to move uphill, it is possible to start uphill control as long as the road surface gradient exceeds this small threshold value. Generation can be prevented, and busy shift can be reduced.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is an overall schematic diagram of a vehicle automatic transmission (and engine) to which the present invention is applied.

The automatic transmission 2 includes a torque converter section 20, an overdrive mechanism section 40, and an underdrive mechanism section 60 having three forward stages and one reverse stage.

The torque converter section 20 includes a pump 2
1, a turbine 22, a stator 23, and a lock-up clutch 24. The output of the crankshaft 10 of the engine 1 is
Transmit to 0.

The overdrive mechanism 40 includes a sun gear 43, a ring gear 44, a planetary pinion 42,
And a set of planetary gear units consisting of
The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism 60 includes two sets of planetary gear units including a common sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67. Rotation state, the overdrive mechanism 40 and the output shaft 70
To the clutch C1, C2, brake B1 ~
It is controlled by B3 and one-way clutches F1, F2.

A computer 84 for controlling the automatic transmission 2
The throttle sensor 80 detects a throttle opening to reflect the load of the engine 1 or the accelerator opening, a vehicle speed sensor (rotation speed sensor of the output shaft 70) 82 detects a vehicle speed, a parking range, a drive range, and L
A shift position switch 86 that outputs a signal of a shift position selected by a driver such as a range, a foot brake switch 88 that outputs a signal when a foot brake is depressed, and an engine speed sensor 90 that detects an engine speed. , An idle contact switch 92 that outputs the state of the idle contact (on when the accelerator is released, off when the pedal is depressed), selects whether to drive with emphasis on power performance (power pattern) or on fuel efficiency (normal pattern) Pattern select switch 94, a cruise control switch 97 for realizing cruise control (automatic constant vehicle speed running), an overdrive off switch 97 for prohibiting running in overdrive (fourth speed), and the like. Signal is input.

The information from the vehicle speed sensor 82 is also used to determine the actual running acceleration of the vehicle.

The computer 84 first obtains a gear position to be selected according to a preset (similar to the conventional) basic map of throttle opening-vehicle speed using input signals from the respective sensors, switches and the like as parameters. Then, the solenoid valves S 1, S 2, S 3, S 4, etc. in the hydraulic control circuit 98 are driven and controlled so as to achieve the gear stage. As a result, as shown in FIG. 3, the clutches, brakes, and the like are engaged or disengaged, and the four forward speeds (the fourth speed is overdrive) and one reverse speed are achieved.

Here, the computer 84 is shown in FIGS.
According to the control flow as shown in FIG. 6, special control on an uphill or downhill is performed according to the traveling state.

FIG. 4 shows a schematic flow of the special control on the uphill or downhill.

In order to facilitate understanding of the control flow, an outline of this special control will be described first.

<Control on Uphill Road> When it is determined that the vehicle is traveling on an uphill road, it is prohibited to shift down to third gear and then upshift to fourth gear under predetermined conditions. (Even if it is determined on the basic shift map that the shift up to the fourth speed should be performed), the third speed is held.
The main purpose is to secure the power performance and prevent the busy shift.

On an uphill road, the forced downshift from the fourth speed to the third speed is not performed. That is, only when it is determined on the basic shift map that the gear should be shifted down from the fourth gear to the third gear, the gear is shifted down in synchronization with the shift. The reason for this is that if the driver shifts down at an unexpected time while the accelerator pedal is being depressed, the driver may feel uncomfortable.

The return of the uphill control is performed immediately when a prerequisite condition for the uphill / downhill control described later is not satisfied.
When the condition of the uphill road is not satisfied, the process is performed after a predetermined return timer (delay time) has elapsed.

While the return timer is operating, the threshold value of the road surface gradient (specifically, a first gradient, which will be described later) for determining a downhill road is changed and set to a small value. In comparison, the vehicle is more likely to be determined to be a downhill road.

<Control on a Downhill Road> In the control on a downhill road, the threshold value (predetermined value) of the road surface gradient for determining "downhill road" is two types of a relatively large first gradient and a smaller second gradient. Be prepared.

Further, as described above, the first gradient is set so that the value of the first gradient itself becomes smaller when the return timer of the ascending control is in operation than when the timer is not operating. The transition to the downhill road can be performed smoothly (without causing unnecessary shifting).

When it is determined that the vehicle is going downhill with the first gradient as a threshold value, the following control is executed.

That is, when the vehicle is traveling at the fourth speed, the gear is shifted down from the fourth speed to the third speed under the conditions of accelerator release and foot brake on. This is a forced downshift that is not synchronized with the shift determination on the basic shift map, but does not give the driver a sense of incongruity because the foot brake is on.

When the vehicle is traveling at the third speed, the vehicle is shifted up to the fourth speed as long as the conditions of the downhill road, the accelerator release, and the foot brake on which are greater than the first gradient are satisfied. The third gear is held (even if it is determined on the basic shift map that the gear should be shifted up to the fourth gear). Since the first gradient is set to be relatively large, the frequency at which the control relating to the first gradient is executed is reduced as compared with the related art, and the busy shift is prevented.

On the other hand, the control of the downhill road according to the second gradient is executed as follows.

That is, when the accelerator is depressed, the fourth
If the accelerator is released and the foot brake is operated within a predetermined time from the accelerator release while traveling at the speed,
Assuming that the driver intends to decelerate (even if the gradient is gentle), the driver is forcibly downshifted to the third speed where the engine brake is stronger.

By the way, in the control flow described later, the determination of the downhill road with the second gradient as the threshold is made only when the vehicle is running at the fourth speed with the accelerator depressed. One of the reasons is that it may not be possible to start the determination of a downhill road after the accelerator is released due to the nature of the condition, and the other is that the vehicle is driven at the fourth speed when the accelerator is depressed. This is because the control (shift down) according to the second gradient is executed only when the control is performed. That is, when the vehicle is traveling at the third speed when the accelerator is depressed and the upshift to the fourth speed is performed with the release of the accelerator, the second speed is established.
The control for the gradient does not return to the third speed again.

The reason is that the control according to the second gradient is executed to shift down to the third speed again until such time as shifting up to the fourth speed due to the release of the accelerator. Thus, when the driver repeatedly depresses, releases, and operates the foot brake on a gentle downhill road, the shift is executed very frequently, and the time required to travel in the third speed (low speed) is accordingly increased. This is because the fuel consumption becomes longer than necessary and the fuel efficiency deteriorates.

Therefore, for the same purpose, in the case of the control of the downhill road with the second gradient as the threshold value, the control of holding at the third speed is not executed. Therefore, the upshift from the third speed to the fourth speed is freely performed in accordance with the switching in the basic shift map.

The return of the downhill control is immediately performed in principle when the above-mentioned condition of the uphill / downhill control described later is not satisfied. However, when the condition of the downhill road is not satisfied, after the predetermined return timer elapses. Done.

When the return timer is operating, the threshold value of the road surface gradient for judging the uphill road is changed and set to be smaller than when the return timer is not operating, and the transition from the downhill control to the uphill control is usually performed. It is designed to be smooth without any control.

Hereinafter, a control flow for executing the above-described ascending and descending slope control will be described with reference to FIG.

When the control flow starts, first,
In step 102, it is determined whether or not a precondition for executing the uphill / downhill control is satisfied.

The prerequisites are common to the uphill road and the downhill road. Specifically, 1) the vehicle speed sensor 82 of the automatic transmission is normal, and 2) the shift position switch 86 is set to the drive range. 3) that either the third speed stage or the fourth speed stage is outputting, 4) the vehicle speed is equal to or higher than a predetermined value and equal to or lower than a predetermined value, for example, 1
5) The vehicle is in the range of 5 km / h to 125 km / h. 5) The overdrive off switch 97 is off (inactive), that is, the overdrive (fourth speed) is in a state where it can be permitted. 6) The cruise control switch 96 is turned off, specifically, the cruise non-control state is continuously detected for a predetermined time T1 or more.

If any one of these conditions is not satisfied, the routine proceeds to step 124, where each flag is reset to zero. As a result, the control flow of FIG. 4 is substantially ended.

It is to be noted that the condition that the vehicle speed sensor 82 of the automatic transmission is normal in 1) is that if the vehicle speed sensor 82 has failed, the vehicle must go up or down the slope in order to execute this control. This is because the determination itself cannot be made.

In 2) and 3), the third drive range
The condition that one of the speed stage and the fourth speed stage is being output is a condition that this control is executed only for the hold or downshift in the third speed stage and the fourth speed stage of the drive range. That's why.

In 4), the condition that the vehicle speed is within the predetermined value is a condition that the vehicle speed is equal to or lower than the predetermined value (outside the applicable range of the present control). This is because when the vehicle speed is equal to or higher than a predetermined value, the vehicle should be maintained at the fourth speed to prevent engine overrun.

In 5), the condition that the overdrive off switch is in the non-operation state is set as a condition that the driver is intentionally avoided from traveling in the overdrive (fourth speed), and that the overdrive off switch is not operated. This is because there is no room for executing hold and downshift at the third speed and the fourth speed by control.

The condition that the cruise control is not operated in 6) is based on the condition that, when the cruise control is executed, the gear position is determined by a separate routine in order to keep the vehicle speed constant. Is automatically controlled.

If it is determined in step 102 that all the preconditions are satisfied, the flow proceeds to step 104. In step 104, it is determined whether a condition for determining an uphill road is satisfied. In this case, a slight hysteresis is provided between when a non-uphill road is determined to be an uphill road and when an uphill road is determined to be a non-uphill road.

Specifically, MOBG ≦ SBG43-KD
When it is determined that the GSF has been established for the predetermined time T2 or longer, it is determined that the vehicle has approached an uphill road from a non-uphill road. On the other hand, MOBG> SBG43−KDGSN is equal to the predetermined time T3.
When it is determined that the above has been established, it is determined that the vehicle has shifted from the uphill road to the non-uphill road.

Here, MOBG indicates the actual acceleration of the vehicle calculated from the output of the vehicle speed sensor (the rotational speed sensor of the output shaft 70 of the automatic transmission) 82, and the SBG 43 indicates each speed change using the throttle opening and the vehicle speed as parameters. Gear (third gear,
The reference vehicle acceleration when traveling on a flat road is mapped in advance for each fourth speed stage. Both may be positive or negative depending on the condition. KDGSF is a predetermined value (positive only) mapped in advance so as to be constant up to the middle vehicle speed and large at a high vehicle speed depending on the vehicle speed, and KDGSN is a select pattern (power pattern, normal pattern) by the pattern select switch 94. ) Is a predetermined value (positive only) mapped in advance so as to increase at a high vehicle speed depending on the vehicle speed.

When the vehicle speed (output shaft rotation speed) is the same, KDGSF> KDGSN (normal)> KDGSN
(Power). The reason why KDGSF is set to be larger than KDGSN is to give hysteresis to the determination, and KDGSF is set to be larger than KDGSN (power).
The reason that the DGSN (normal) is set larger is that it is more difficult to determine that the vehicle has shifted from the uphill road to the non-uphill road in the power pattern than in the normal pattern. In order to keep the state longer. If the third gear is maintained for a longer time, the fuel economy will slightly decrease, but the busy shift will be prevented and the acceleration and the effectiveness of the engine brake will be improved by that much, so that the traveling sensitive to the movement of the accelerator pedal can be performed accordingly. .

Here, KDGSF used for determination when shifting from a non-uphill road to an uphill road is a value reduced by a first predetermined value when a later-described downhill return timer is operating, and as a result, KDGSN The value is extremely small (small). As a result, when the downhill return timer is in operation, it is determined that the vehicle has approached an uphill road from a non-uphill road even with a relatively gentle road surface gradient.

It should be noted that the above-described determination of the uphill road (step 1)
FIG. 5 is a flowchart of FIG.
Shown in In FIG. 5, in step 600, the SBG4
After searching the map No. 3, steps 602, 604-
Reference numeral 610 corresponds to a path for determining that the vehicle has transitioned from a non-uphill road to an upward road, and steps 602, 612, and 614 correspond to a path for determining that the vehicle has transitioned from a non-upward road to a non-upward road.

If it is determined in step 606 that the downhill return timer is running, in step 608, KDGSF is redefined to a value lowered by a first predetermined value. As a result, the determination in step 610 becomes extremely easy to be made, and it is easy to determine that the road is an uphill road. It should be noted that once the road is determined to be an uphill road, the flow proceeds from step 602 to the side 612, so that the determination of the uphill road is maintained unless the gradient of the uphill road becomes equal to or less than the lower limit of hysteresis.

When it is determined that the vehicle is on an uphill road, the process proceeds to step 106, where the uphill road determination flag F0 is set to 1. On the other hand, when it is determined that the vehicle is not on an uphill road, the process proceeds to step 108. Proceed to the flag F0
Is reset to zero.

When the uphill determination flag F0 changes from 1 to 0, the uphill return timer, which will be described later, starts counting up.

In step 110, it is determined whether or not the vehicle is on a downhill road. If it is determined in step 106 that the road is an uphill road, step 110 is bypassed because it is not necessary to determine a downhill road.

The determination of the downhill road is executed in accordance with a control flow as shown in FIG.

That is, when the uphill determination flag F0 is reset to zero in step 108, the flow proceeds to step 1.
The process proceeds to step 10, and in step 200, it is determined whether the idle contact switch 92 is on, that is, whether the accelerator is released.

If it is determined that the idle contact is on, the flow proceeds to step 202 where the SBGE 43 map is searched. The SBGE 43 is a gear stage (third gear).
(First speed, fourth speed), reference vehicle acceleration for downhill road (positive / negative) mapped in advance based on the first road surface gradient (first gradient) depending on the vehicle speed for each select pattern.
That is.

The manner in which the SBGE 43 depends on the vehicle speed is not limited to the dependence that the predicted acceleration (based on a flat road) becomes smaller because the running resistance increases when the vehicle speed is simply higher. In the high vehicle speed range and the low vehicle speed range, the first gradient itself is made to depend more steeply than in the middle vehicle speed range. As a result, in step 212 or 210, the middle vehicle speed is most likely determined to be a downhill road.

In step 204, it is determined whether or not a later-described uphill return timer is operating. If it is in operation, the routine proceeds to step 206, where the SBGE 43 is newly defined to a value lowered by the second predetermined value.
As a result, in a case where a transition from an uphill road to a downhill road is performed while the uphill return timer is operating, the determination as a downhill road can be easily performed even if the road surface gradient is relatively gentle.

In step 208, it is determined whether or not the first downhill road determination flag F1 is zero. If the first downhill road determination flag F1 is 1, that is, if it has been determined that the road is a downhill road having the first slope or more, step 21 is executed.
Then, it is determined whether the actual acceleration MOBG of the vehicle calculated from the output of the vehicle speed sensor 82 is smaller than the reference vehicle acceleration SBGE43 for the downhill road relating to the first gradient obtained in step 202 by a predetermined time T4 or more. You. If it is not small, keep it as it is (the first downhill road determination flag F1 remains 1)
The process proceeds to step 116, but when it is smaller, the process proceeds to step 114, where the first downhill determination flag F1 is reset to zero, and then to step 116.

In step 208, the first downhill road determination flag F
When it is determined that 1 is zero, the routine proceeds to step 210, where the actual vehicle acceleration MOBG is set to the reference vehicle acceleration SBGE.
It is determined whether the value is larger than the predetermined time T5 by more than a predetermined time T5. If the value is larger than the predetermined time T5, the first downhill road determination flag F1 is set to 1 in step 112;
Proceed to 6.

When the first downhill road determination flag changes from 1 to 0, the count-up of a return timer t described later is started.

According to the above control flow, the determination of the downhill road with the first gradient as the threshold is executed. Note that, as described above, the first gradient itself has a characteristic that depends on the vehicle speed and whether or not it is during the uphill return timer.

On the other hand, if it is determined in step 200 that the idle contact is not on, that is, if it is determined that the accelerator pedal is being depressed, the routine proceeds to step 214, where it is determined whether or not the current actual gear is the fourth gear. Is determined.
If it is the fourth speed, the program proceeds to step 216, where KD
The EG map is searched. The KDEG is higher in the high vehicle speed range and lower vehicle speed range so as to have the same tendency as the SBGE 43 depending on the vehicle speed (output shaft rotation speed).
The map is set to a predetermined value (acceleration: positive only) that is set to be larger than when the vehicle is in the middle vehicle speed range, and as a result, corresponds to a second road surface gradient (second gradient) smaller (slope) than the first gradient. It is something that has been.

As described above, the SBGE 43 or the KD
By making the EG into a map based on the vehicle speed or the output shaft speed, the gradient that is the threshold value for the determination of the downhill road can be freely changed and set depending on the vehicle speed.

In step 218, it is determined whether or not the road is determined to be a downhill road when the second gradient is set as a threshold value, that is, whether the value of the second downhill road determination flag F10 should be zero or one. You. Specifically, when the value of the flag F10 is currently zero, MOBG> SBG43 + KDEG + KD
If GE is not less than the predetermined time T6, the process proceeds to step 220.
The flag F10 is set to 1. When the current flag F10 is 1, MOBG ≦ SBG43 + KD
When the EG is equal to or longer than the predetermined time T7, step 222 is executed.
The flag F10 is reset to zero. Where SBG
As described above, reference numeral 43 denotes a reference vehicle acceleration on a flat road (for an uphill road) constituted by both parameters of the throttle opening and the vehicle speed, and KDGE is a predetermined value (positive only) for giving hysteresis. .

On the other hand, if it is determined in step 214 that the current speed is not the fourth speed, that is, it is the third speed, the process directly proceeds to step 222, where the second downhill road determination flag F10 is set to zero. Is reset to

The first in step 110
The processing of the downhill road determination flag F1 is always reset to zero when it is determined that the idle contact is off (regardless of the value of the second downhill road determination flag F10).

The reason why the determination of the downhill road according to the second gradient is performed only when the idle contact is off and the vehicle is running at the fourth speed is as described above.

Returning to FIG. 4, step 1 is thus performed.
When it reaches 16, it is determined here whether the climbing control start condition is satisfied. Specifically, 1) the foot brake switch 88 is off (the brake is not depressed), 2) the idle contact switch 92 is off (the accelerator is depressed), and 3) the third speed based on the basic shift map. The power-on downshift (downshift when the accelerator is depressed) is satisfied, or one of the outputs of the third speed stage after the determination is satisfied is satisfied. 4) The condition that the uphill road determination flag F0 is 1 When all of the conditions have been satisfied, it is determined that the ascending control start condition has been satisfied, and the routine proceeds to step 118, where the fourth speed position inhibition request flag F2 for the ascending road is set to 1. If any of the conditions 1) to 4), which are the conditions for starting the hill-climbing control, are not satisfied, step 118 is bypassed.

In the above 3), the determination of the power-on downshift to the third speed or the output of the third speed based on the basic shift map is one of the conditions for starting the uphill control, as described above. While the vehicle is traveling in the speed range, the control is executed (when the driver does not intend) to change from the fourth speed stage to the third speed stage.
This is to prevent a downshift to the first gear. That is, in the uphill control, the downshift from the fourth speed to the third speed is not actively performed, and only the upshift from the third speed to the fourth speed is prevented.

On the other hand, in step 120, it is determined whether or not the condition for starting downhill control is satisfied.

Specifically, 1) the idle contact switch 92 is turned on (the accelerator is released), 2) the foot brake switch 88 is turned on (the brake is depressed), and 3) the first downhill road determination flag. When all of the conditions that F1 is 1 are satisfied, or 4) The foot brake switch 88 is turned on (the brake is depressed). 5) It is within a predetermined time t0 after the idle contact switch 92 is turned on. 6) When all of the conditions for setting the second downhill road determination flag F10 to 1 are satisfied, it is determined that the downhill control start condition is satisfied, and the routine proceeds to step 122, where the fourth speed position inhibition request flag F3 for the downhill road is set. Set to 1.

If the condition for starting the descent is not satisfied, step 122 is bypassed. Therefore, at this time, the fourth-speed-gear prohibition request flag F3 for the downhill road is not set to 1.

In this way, when step 126 is reached,
Thereafter, actual processing is performed based on the value of each flag.
First, at step 126, it is determined whether or not the uphill determination flag F0 is zero. In step 128, it is determined whether the fourth-speed-gear prohibition request flag F2 for the uphill road is "1".

When it is determined that the fourth-speed-gear prohibition request flag F2 for the uphill road is 1 even though the uphill road determination flag F0 is zero, the routine proceeds to step 130, where the above-described uphill control return timer is executed. It is determined whether or not is completed. If it has been completed, the fourth step for climbing in step 132
The speed-gear prohibition request flag F2 is reset to zero, but if not finished, the routine proceeds to step 142 (114), where the fourth speed-gear prohibition request flag F2 for uphill or downhill road,
The value of F3 is checked, and if either one is 1, the fourth speed is prohibited in step 146. If both are zero, the control flow ends without prohibiting the fourth speed.

On the other hand, when it is determined that the uphill determination flag F0 is not zero, or even when it is determined that the flag F0 is zero, it is determined that the fourth speed position inhibition request flag F2 for the uphill is not 1. If so, the process proceeds to step 134.

At step 134, the value of the first downhill road determination flag F1 is determined. In step 136, it is determined whether or not the fourth-speed-gear prohibition request flag F3 for the downhill road is "1". When it is determined that the fourth-speed-stage-prohibition request flag F3 for the downhill road is 1 even though the first downhill-road determination flag F1 is zero, the routine proceeds to step 138, where the above-described downhill control return timer is started. It is determined whether or not the process has been completed.
The gear stage prohibition request flag F3 is reset to zero.

However, the first downhill road determination flag F1
Is not zero, or even if it is zero, the fourth
If the gear-stage prohibition request flag F3 is not 1 or if it is determined that the downhill control return timer has not expired, the routine proceeds to step 142 (144), where the fourth speed for uphill or downhill roads is entered. If one of the gear inhibition request flags F2 and F3 is 1, the fourth gear is inhibited in step 146. If both are zero, the control flow ends without prohibiting the fourth speed.

According to this embodiment, as described above, the basic threshold value for determining a downhill road can be set to a relatively large value (first gradient). Control can be prevented from being executed, and when the foot brake is operated within a predetermined time after the accelerator is released, it is considered that the driver wants rapid deceleration, Even when the vehicle is traveling on a road with a very small road surface gradient (second gradient), it is possible to surely shift down to a low gear. As a result,
The driver's true deceleration request can be reflected in the shift control more than before, and the driving feeling can be improved accordingly.

Further, in this embodiment, as described above, in the determination of the downhill road while the uphill return timer is operating, the threshold value of the road surface gradient for the determination is set lower. Similarly, in the determination of the uphill road while the downhill return timer is operating, the threshold value of the road surface gradient for the determination is also set to a lower value. As a result, in the case of traveling on a mountain road where the uphill road and the downhill road are repeated,
The uphill control and the downhill control can be continued (without going through the normal control), and the busy shift can be effectively prevented.

In particular, in this embodiment, the first slope and the second slope are provided in the determination of the downhill road, and the vehicle is approaching the downhill road at the relatively large first gradient unless special conditions are satisfied. If the control for reducing the first gradient is not performed while the uphill return timer is operating, it is not possible to smoothly continue from the uphill control to the downhill control. It is considered that the possibility of occurrence of the situation returning to is increased. However, such a situation can be prevented beforehand by the control for reducing the first gradient.

Further, according to this embodiment, as described above, the first gradient and the second gradient are changed so as to have larger values in the high vehicle speed region and the low vehicle speed region than in the middle vehicle speed region. Since it is set, it is possible to prevent the vehicle from entering the downhill control more than necessary at high vehicle speed and low vehicle speed.

Accordingly, the acceleration itself is small due to the increase in the running resistance, and therefore, at a high vehicle speed where the execution of the downhill control is not so required, or the effect of the engine brake itself is small, the execution of the downhill control is also performed so much. It is possible to prevent the gear from being downshifted to an unnecessarily low gear when the vehicle speed is not required.

As a result, the driver's request for deceleration can be more appropriately reflected in the shift control than before, so that a busy shift can be prevented and the driving feeling can be improved.

[0096]

As described above, according to the present invention,
The threshold value for determining the uphill road when the downhill return timer is operating and the threshold value for determining the downhill road when the uphill return timer is operating are lower than the threshold values when the respective return timers are not operating. As a result, in a running state in which the uphill road and the downhill road are repeated, the uphill control and the downhill control can be smoothly continued without passing through the normal control, and as a result, the busy shift can be prevented. An excellent effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a skeleton diagram of an automatic transmission for a vehicle to which the present invention is applied;

FIG. 3 is a diagram showing an operation state of the friction engagement device of the automatic transmission.

FIG. 4 is a flowchart showing a control flow executed in the embodiment.

FIG. 5 is a flowchart showing details of step 104 in FIG. 4;

FIG. 6 is a flowchart showing details of step 110 in FIG. 4;

[Explanation of symbols]

 80 ... Throttle sensor 82 ... Vehicle speed sensor (output shaft speed sensor) 84 ... Computer 86 ... Shift position switch 88 ... Foot brake switch 92 ... Idle contact switch 94 ... Pattern select switch MOGB ... Real vehicle acceleration SGB43 ... (on a flat road) ) Reference vehicle acceleration SBGE43 ... Reference vehicle acceleration (on a downhill road)

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yoshiharu Harada 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-1-1755531 (JP, A) JP-A-62-168725 (JP, A) JP-A-63-18659 (JP, U) JP-B-61-48019 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00-61 / 12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (2)

(57) [Claims] A means for judging whether or not the vehicle is traveling on an up-down sloping road, wherein when it is determined that the vehicle is traveling on an up-down sloping road, a speed suitable for the up-down sloping road is established and when the up-slope control is released. In a control device for an automatic transmission for a vehicle on an uphill or downhill road configured to release the uphill control after a predetermined delay time has elapsed, means for determining whether or not a current time point is within the delay time is provided. Means for setting a threshold value of a road surface gradient as a criterion in the determination of the downhill road when the delay time is during the delay time as compared with when the delay time is not during the delay time. Control device for automatic transmission for vehicle on slope. Means for judging whether or not the vehicle is traveling on an uphill or downhill, and when it is determined that the vehicle is traveling on an uphill or downhill, a speed suitable for the uphill or downhill is established and the downhill control is released. When a predetermined delay time has elapsed, the control device for an automatic transmission for a vehicle on an uphill slope configured to release the downhill control after a lapse of a predetermined delay time determines whether or not the current time is within the delay time. And a means for setting a threshold value of a road surface gradient as a criterion for determination of the uphill road, when the delay time is during the delay time, as compared to when the delay time is not during the delay time. Of automatic transmission for vehicles on a climbing slope.