JPH0828697A - Control device of automatic transmission for vehicle on downhill/uphill road - Google Patents

Abstract

PURPOSE:To reduce busy shift by setting the threshold of the road surface gradient which is the reference for the judgement to be smaller compared with the value when in the delay time to release the uphill control compared with when not in the delay time. CONSTITUTION:An automatic transmission 2 switches the transmission characteristic by judging whether or not the vehicle is traveling on the downhill road in a computer 84 to input the output signals from a throttle sensor 80, a vehicle speed sensor 82, a foot brake switch 88, etc. A means to judge whether or not the vehicle is traveling on the uphill/downhill road is provided, and when a judgement is made that the vehicle is traveling on the uphill/downhill road, the transmission step suitable to the uphill/downhill road is set. When the uphill control is released, the uphill control is released after the prescribed delay time is elapsed. A means to judge whether or not the present time is in the delay time is provided, and in making a judgement of the downhill road, the threshold of the road surface gradient which is the reference for the judgement is set to be smaller when in the delay time compared with when not in the delay time.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Generally, in automatic transmissions for vehicles,
A gear shift map having vehicle speed and engine load (throttle opening degree, etc.) as parameters is provided, and the gear stage to be selected is determined by applying the information of the vehicle speed and engine load at that time during traveling to this gear shift map. .

However, since this shift map is created on the basis of a general flatland traveling state, it does not always give an optimum shift speed when traveling on a downhill road or an uphill road, for example.

In view of such circumstances, for example, Japanese Patent Publication Sho 59
Japanese Unexamined Patent Publication No. -8698 proposes a technique of separately providing a shift map according to a state of a traveling road such as traveling on a flat road and traveling on an uphill road, and appropriately switching these maps for use.

In this Japanese Patent Publication No. 59-8698, a reference vehicle acceleration (expected value of running acceleration) on a flat road is obtained in advance using parameters such as throttle opening and vehicle speed, and the reference vehicle acceleration and the vehicle speed are used. Also disclosed is a technique for comparing the calculated actual vehicle acceleration and determining that the actual acceleration is running on a downhill road when the actual acceleration is greater than a reference acceleration by a predetermined value or more, and the vehicle is traveling on an uphill road when the actual acceleration is smaller than the reference acceleration. Has been done.

When it is determined that the vehicle is traveling on an uphill or downhill road, generally, in order to improve the power performance in the uphill road and in order to apply more engine braking in the downhill road, the low speed Control to maintain on the side is made.

By the way, the road gradient is, for example, in the case of transition from an uphill road to a downhill road, specifically,
Then change to the downhill road. Therefore, the uphill / downhill control may shift from the uphill control to the normal control and then to the downhill control according to the change of the road surface gradient, and a shift may be performed each time the control shifts, resulting in a busy shift (frequent shift). is there.

Therefore, for example, in Japanese Unexamined Patent Publication Nos. 5-71623 and 71625 or Japanese Patent Publication No. 61-48019, a certain delay time is provided when the uphill / downhill control is canceled, and the cancellation is performed after the delay time has elapsed. Therefore, a technique for preventing a busy shift has been proposed.

[0009]

When performing the uphill / downhill control, for example, with respect to the threshold value of the road surface gradient, if the threshold value is set too small, the uphill / downhill control will be performed even on the road surface with a slight slope, and thus the busy shift will occur. It tends to occur. Therefore, from the viewpoint of preventing busy shift, it is necessary to set the threshold value of the road surface gradient that determines whether or not to enter the uphill / downhill control to a relatively large value.

However, if the threshold value of the road surface slope for entering the uphill / downhill control is set to a large value, in a situation where an uphill road and a downhill road such as a mountain road are frequently repeated, for example, the downhill road is lowered. When shifting to a slope, even if there is a delay time, as long as the actual slope of the descending slope does not exceed the threshold value of the road slope (which is set to be large), the slope control will be performed with the delay time. Since it is released and returned to the normal control, the gear shift often occurs there. Then, when the gradient of the downhill road becomes so tight that it exceeds the threshold value, the normal control is shifted to the downhill control at that point, so that the gear shift is generated again.

Although such a problem can be solved to some extent (for the problem of busy shift) by increasing the delay time to be set, in a situation where the uphill / downhill control should be truly released. However, there is a problem that the release will be 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 uphill control is followed by the downhill control or the downhill control is followed by the uphill control. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle on an ascending / descending slope road, which can surely reduce busy shift even in a traveling state that may occur.

[0013]

In the present invention, FIG.
As shown in (A) of FIG. 7, a means for determining whether or not the vehicle is traveling on an uphill / downhill road is provided, and when it is determined that the vehicle is traveling on the uphill / downhill road, the shift stage is suitable for the uphill / downhill road. In a control device for an automatic transmission for a vehicle on an uphill / downhill 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. And a means for setting the threshold value of the road surface slope, which is a criterion for judgment in determining the downhill road, to be smaller during the delay time than during non-delay time. As a result, the above object has been achieved.

Further, as shown in the outline of FIG. 1 (B), a means for judging whether or not the vehicle is traveling on an uphill / downhill road is provided, and when it is judged that the vehicle is traveling on an uphill / downhill road, the uphill / downhill road is changed to When releasing the downhill control while setting the appropriate shift speed,
In a control device for an automatic transmission for a vehicle on an uphill road configured to release the downhill control after a lapse of a predetermined delay time, means for determining whether or not the present time is within the delay time. , The means for setting the threshold value of the road surface gradient, which is a criterion for judgment in the determination of the uphill road, to be smaller when the delay time is set than when the delay time is not set. It has been achieved.

[0015]

In the present invention, the delay time is set when canceling the uphill / downhill control. If the current time point corresponds to the delay time, it is set during the uphill control delay time. If there is a slope, when determining the downhill road, on the other hand, when it is during the delay time in downhill control, when determining the uphill road, the threshold of the reference road slope is compared to when it is not during the delay time. I tried to set it small.

As a result, when shifting from an uphill road to a downhill road, even if it is impossible to completely move to the downhill road during the delay time, the road surface gradient is smaller than the smaller threshold value. As long as it is large, it is possible to directly shift from uphill control to downhill control without returning to normal control. As a result, the gear can be maintained at the low speed, and the busy shift can be prevented.

In the same manner, even when the downhill road is changed to the uphill road, the threshold for judging the uphill road is set to be low during the delay time of the downhill road. Even if you can not move to the uphill road, you can enter the uphill control as long as the road surface gradient is above this small threshold value, so even in this case, you may return to the normal control once. It can be prevented from occurring and busy shift can be reduced.

[0018]

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

FIG. 2 is an overall schematic view 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 are well-known, and the output of the crankshaft 10 of the engine 1 is supplied to the overdrive mechanism unit 4.
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 gears consisting of a carrier 41,
The rotation state of this planetary gear device is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism section 60 is provided with two sets of planetary gear units consisting of 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
The connection state with the clutches C1, C2, the brake B1 ~
It is controlled by B3 and one-way clutches F1 and F2.

Computer 84 for controlling the automatic transmission 2
Is a throttle sensor 80 that detects the throttle opening for reflecting the load of the engine 1 or the accelerator opening, a vehicle speed sensor (rotational speed sensor of the output shaft 70) 82 that detects the vehicle speed, a parking range, a drive range, 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 the foot brake is stepped on, 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), and chooses whether to drive with emphasis on power performance (power pattern) or travel with emphasis on fuel efficiency (normal pattern). For various controls such as a pattern select switch 94, a cruise control switch 97 for realizing cruise control (automatic constant vehicle speed traveling), an overdrive off switch 97 for prohibiting traveling in overdrive (4th speed), and the like. A signal is being input.

The information of the vehicle speed sensor 82 is also used to obtain the actual traveling acceleration of the vehicle.

The computer 84 uses the input signals from the respective sensors, switches, etc. as parameters to determine the gear stage to be selected first according to a preset (the same as the conventional) basic shift map of throttle opening-vehicle speed. Then, the solenoid valves S1, S2, S3, S4, etc. in the hydraulic control circuit 98 are driven and controlled so that the shift speed is achieved. As a result, as shown in FIG. 3, the respective clutches, brakes, etc. are engaged or released, and four forward gears (the fourth gear is overdrive) and one reverse gear are achieved.

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

FIG. 4 shows a schematic flow of the special control on the ascending / descending road.

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

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

In the case of an uphill road, the forced downshift from the fourth speed stage to the third speed stage is not executed. That is, only when it is determined on the basic shift map that the downshift from the fourth speed to the third speed should be performed, the downshift is performed in synchronization with it. The reason is that there is a risk of discomfort if a downshift is executed at a time when the driver does not expect while the vehicle is stepping on the accelerator.

The uphill control is restored immediately when the preconditions for uphill downhill control, which will be described later, are not satisfied.
When the condition of the uphill road is not satisfied, it is performed after a predetermined return timer (delay time) has elapsed.

While the return timer is operating, the threshold value of the road surface slope (specifically, the first slope described later) for determining the downhill road is changed and set to a small value, and when the return timer is not operating. Compared to this, it is more likely to be judged as a downhill road.

<Control on a Downhill Road> In the control on a downhill road, there are two types of first slope and a second slope which are relatively large in the threshold value (predetermined value) of the road surface slope for determining the “downhill road”. Be prepared.

Further, as described above, the first gradient is set such that when the uphill control return timer is operating, the first gradient itself has a smaller value than when it is not. The transition to a downhill road is made smooth (without causing unnecessary shifts).

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

That is, when the vehicle is traveling at the fourth speed, the gear is downshifted 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 the driver does not feel uncomfortable because the foot brake is on.

Further, 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 descending slope having a slope larger than the first slope, the accelerator release, and the foot brake on are continuously satisfied. It is prohibited, and the third speed is held (even if it is determined on the basic shift map that the fourth speed should be shifted up). Since the first gradient is set to be relatively large, the frequency with which the control relating to the first gradient is executed is reduced as compared with the conventional case, and the busy shift is prevented.

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

That is, when the accelerator is depressed, the fourth
When the accelerator is released and the foot brake is operated within a predetermined time after the accelerator is released while traveling at a high speed,
Assuming that the driver intends to decelerate (even on a gentle slope), the engine is forcibly downshifted to the third speed with stronger engine braking.

By the way, in the control flow described later, the downhill road is determined with the second gradient as the threshold value only when the accelerator pedal is depressed and the vehicle travels at the fourth speed. This is because, because of the nature of the conditions, it may not be enough to start the downhill road judgment after the accelerator is released, and the other is that the vehicle runs at the fourth speed when the accelerator is depressed. This is because the control (shift down) related to the second gradient is executed only when the above-mentioned situation has occurred. That is, when the vehicle is traveling at the third speed when the accelerator is depressed and the vehicle is upshifted to the fourth speed when the accelerator is released, the second speed
It does not return to the third speed again by the control related to the gradient.

The reason for this is that the control relating to the second gradient is executed and the gear is downshifted to the third speed again until the fourth gear is upshifted with the release of the accelerator. In this case, when the driver repeatedly depresses the accelerator, releases the pedal, and repeatedly operates the foot brake on a gentle downhill road, the gear shift is executed very frequently, and the time for traveling in the third speed (low speed) is increased. This is because it becomes longer than necessary and fuel efficiency deteriorates.

Therefore, for the same reason, 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, upshifting from the third speed stage to the fourth speed stage can be carried out freely as the basic shift map is changed.

As a general rule, the return of the downhill control is immediately performed when the above-mentioned conditions of the uphill / downhill control which will be described later are not satisfied, but when the conditions of the downhill road are not satisfied, after a predetermined return timer elapses. Done.

While the return timer is operating, the threshold value of the road surface slope for judging an uphill road is changed and set to be smaller than that when the return timer is not operating, and the downhill control is normally shifted to the uphill control. It is designed so that it can be done smoothly without any control.

The control flow for executing the above-described uphill / downhill control will be described below with reference to FIG.

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

This precondition is 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) Either the third speed or the fourth speed is being output, 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
Within the range of 5 km / h to 125 km / h, 5) Overdrive off switch 97 is off (non-acting), that is, overdrive (4th speed) is in a permissible state, 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.

In 1), the condition that the vehicle speed sensor 82 of the automatic transmission is normal is that the vehicle speed sensor 82 fails, and if the vehicle speed sensor 82 fails, it is an essential climbing and descending slope for executing this control. This is because the judgment itself cannot be made.

2) The third drive range in 3)
The condition that either the first speed or the fourth speed is being output is that the present control is executed only for holding or downshifting in the third speed and the fourth speed of the drive range. This is because.

In 4), the condition that the vehicle speed is within the predetermined value is that the second speed or the first speed is outside the applicable range of this control when the vehicle speed is below the predetermined value. This is because when the vehicle is in a state where the vehicle should enter and when the vehicle speed is equal to or higher than the predetermined value, the vehicle should be maintained at the fourth speed to prevent overrun of the engine.

In 5), the condition that the overdrive off switch is in the non-acting state is set as a condition when the driver intentionally avoids traveling in the overdrive (4th speed). This is because there is no room for holding or downshifting in the third speed and the fourth speed by the control.

In 6), the condition that the cruise control is in the non-acting condition is that the cruise control is executed. Is automatically controlled.

When 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 or not the uphill road determination condition is satisfied. In this case, some hysteresis is provided between when the non-uphill road is determined to be an uphill road and when the 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 a predetermined time T2 or more, it is determined that the vehicle is approaching an uphill road from a non-uphill road. On the other hand, when MOBG> SBG43-KDGSN, the predetermined time T3
When it is determined that the above conditions are satisfied, it is determined that the vehicle has changed from an uphill road to a non-uphill road.

Here, MOBG represents the actual acceleration of the vehicle calculated from the output of the vehicle speed sensor (the rotation speed sensor of the output shaft 70 of the automatic transmission) 82, and the SBG 43 represents each shift using the throttle opening and the vehicle speed as parameters. Gear (3rd gear,
4 shows the reference vehicle acceleration during flat road traveling, which is mapped in advance for each fourth speed stage. Depending on both conditions, it may be positive or negative. Further, KDGSF is a predetermined value (only positive) which is previously mapped so as to be constant up to a medium vehicle speed depending on the vehicle speed and increase at a high vehicle speed, and KDGSN is a select pattern (power pattern, normal pattern) by the pattern select switch 94. ) Is also a predetermined value (only positive) that is previously mapped so as to increase at a high vehicle speed depending on the vehicle speed.

When the vehicle speed (output shaft speed) is the same, KDGSF> KDGSN (normal)> KDGSN
It is set to be (power). The reason why KDGSF is set larger than KDGSN is to give a hysteresis to the judgment, and KDGSF is set to K rather than KDGSN (power).
The DGSN (normal) is set to be larger because it is more difficult to judge that the uphill road has changed to the non-uphill road in the power pattern than in the normal pattern. This is because the state of is maintained for a long time. If the third speed is maintained for a longer period of time, the fuel economy will be slightly reduced, but the busy shift will be prevented and the acceleration and engine braking effectiveness will be improved accordingly, allowing the driver to travel more sensitive to the movement of the accelerator pedal. .

Here, the KDGSF used for the determination when shifting from the non-uphill road to the uphill road is a value obtained by subtracting the first predetermined value when the downhill return timer described later is in operation, and as a result, KDGSN. The value is extremely close (small) to (normal). As a result, when the downhill return timer is in operation, it is determined that a non-uphill road is approaching the uphill road even if the road surface has a relatively gentle slope.

It should be noted that the above-described uphill road determination (step 1
04) is summarized in a concrete flow chart in FIG.
Shown in In FIG. 5, in step 600, the SBG4
After searching the map of step 3, steps 602 and 604-
Reference numeral 610 corresponds to the route for determining the transition from the non-uphill road to the uphill route, and steps 602, 612, and 614 correspond to the route for determining the transition from the uphill road to the non-uphill road.

When it is determined in step 606 that the downhill return timer is in operation, step 608 redefines KDGSF to a value lowered by the first predetermined value. As a result, the determination in step 610 is extremely easy to be established, and it is easy to determine that the road is an uphill road. Note that once it is determined that the road is an uphill road, the flow proceeds from step 602 to the 612 side, so that the uphill road determination is maintained unless the slope of the uphill road is equal to or lower than the lower limit of hysteresis.

If it is determined that the vehicle is an uphill road by the above conditions, the routine proceeds to step 106, where the uphill road determination flag F0 is set to 1. On the other hand, if it is determined that the vehicle is not an uphill road, the routine proceeds to step 108. Go 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.

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

The downhill road determination is specifically executed according to the control flow as shown in FIG.

That is, when the uphill road determination flag F0 is reset to zero in step 108, the flow proceeds to step 1
10, the routine proceeds to step 200, where it is determined in step 200 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, then flow proceeds to step 202 where the SBGE 43 map is searched. SBGE43 is a gear position (3rd
Speed, fourth speed), reference vehicle acceleration for downhill roads (positive and negative) that is pre-mapped with the first road surface slope (first slope) as a reference depending on the vehicle speed for each select pattern
That is.

It should be noted that the way the SBGE 43 depends on the vehicle speed is not only dependent on the fact that the predicted acceleration is small (on a flat road) because the running resistance becomes large when the vehicle speed is simply high. The first gradient itself is made to be tighter in the high vehicle speed range and the low vehicle speed range than in the medium vehicle speed range. This makes it easier for the vehicle to be determined to be a downhill road at the medium vehicle speed in step 212 or 210.

In step 204, it is judged whether or not the uphill return timer described later is in operation. When the SBGE 43 is in operation, the process proceeds to step 206 and the SBGE 43 is redefined to a value lowered by the second predetermined value.
As a result, when the uphill return timer shifts from an uphill road to a downhill road while the timer is operating, it is possible to easily determine that the road is a downhill road even if the road surface slope is relatively gentle.

At step 208, it is judged if the first descending road judgment flag F1 is zero. When the first downhill road determination flag F1 is 1, that is, when it has been determined that the road is a downhill road having the first slope or more, step 21
Then, it is judged whether the actual vehicle acceleration MOBG calculated from the output of the vehicle speed sensor 82 is smaller than the reference vehicle acceleration SBGE43 for the downhill road according to the first slope obtained in step 202 by a predetermined time T4 or more. It If it is not smaller, it is as it is (the first downhill road determination flag F1 remains 1)
If it is smaller, the routine proceeds to step 114, where the first downhill road determination flag F1 is reset to zero, and then the routine proceeds 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 the reference vehicle acceleration SBGE.
43, it is judged whether or not it is longer than the predetermined time T5 or more. If it is larger, the first downhill road determination flag F1 is set to 1 in step 112, and if it is not larger, it remains at step 11
Proceed to 6.

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

Through the above control flow, the determination of the downhill road with the first gradient as the threshold value is executed. As described above, the first gradient itself has a characteristic that depends on whether the vehicle speed or the uphill return timer is already being used.

On the other hand, when it is judged at step 200 that the idle contact is not on, that is, when it is judged that the accelerator is being depressed, the routine proceeds to step 214, where it is determined whether the current actual gear is the fourth gear. Is determined.
If it is the 4th speed, proceed to step 216 and perform KD.
The EG's map is searched. This KDEG is in the high vehicle speed range and the low vehicle speed range so that it has the same tendency as the SBGE 43 depending on the vehicle speed (output shaft speed).
Map to correspond to a second road gradient (second gradient) that is a predetermined value (acceleration: positive only) that is set larger than in the middle vehicle speed range, and as a result is smaller (slower) than the first gradient It has been made into.

In this way, SBGE43 or KD
By using EG as a map based on the vehicle speed or the output shaft rotation speed, it is possible to freely change and set the gradient as the threshold value for determining the downhill road depending on the vehicle speed.

At step 218, it is determined whether or not it is determined to be a downhill road when the second gradient is used as a threshold value, that is, whether the value of the second downhill road determination flag F10 should be zero or one. It Specifically, when the value of the flag F10 is currently zero, MOBG> SBG43 + KDEG + KD
If GE is satisfied for a predetermined time T6 or more, step 220
The flag F10 is set to 1. When the current flag F10 is 1, MOBG≤SBG43 + KD
When EG is established for a predetermined time T7 or more, step 222
Then, the flag F10 is reset to zero. Where SBG
As mentioned above, 43 is a reference vehicle acceleration on a flat road (for an uphill road), which is constituted by parameters of both the throttle opening and the vehicle speed, and KDGE is a predetermined value (only positive) for giving hysteresis. .

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

The first step 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 related to the second gradient is made only when the idle contact is off and the vehicle is traveling at the fourth speed is as described above.

Returning to FIG. 4, step 1 is performed in this manner.
When it reaches 16, it is judged here whether or not the slope 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) to the third gear according to the basic shift map. The condition that the power-on downshift (downshift when the accelerator is depressed) judgment is established, or one of the third speed outputs after the judgment is established, 4) The uphill road determination flag F0 is 1. When all the conditions are satisfied, it is judged that the condition for starting the uphill control is satisfied, and the routine proceeds to step 118, where the fourth speed stage prohibition request flag F2 for the uphill road is set to 1. If any of the climbing control start conditions 1) to 4) is 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 after that based on the basic shift map is used as one of the conditions for starting the uphill control, as described above. By executing this control while traveling in the speed stage (when the driver does not intend), the fourth gear position to the third gear position
This is to prevent downshifting to a higher speed. That is, in the uphill control, the positive shift down from the fourth speed to the third speed is not performed, and only the shift up from the third speed to the fourth speed is prevented.

On the other hand, in step 120, it is judged whether or not the downhill control start condition is satisfied.

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

If the downhill start condition is not satisfied, step 122 is bypassed. Therefore, at this time, the fourth speed stage prohibition request flag F3 for downhill road is not set to "1".

When step 126 is reached in this way,
After that, the actual processing is performed based on the value of each flag.
First, at step 126, it is judged if the uphill judgment flag F0 is zero. Further, at step 128, it is judged whether or not the fourth speed step prohibition request flag F2 for the uphill road is 1.

When it is determined that the uphill fourth speed prohibition request flag F2 is 1 even though the uphill determination flag F0 is zero, the routine proceeds to step 130, and the above-described uphill control return timer. Is determined. If finished, go to step 132 for the fourth climb
The speed prohibition request flag F2 is reset to zero, but if not completed, the process proceeds to step 142 (114) to go uphill or downhill the fourth speed prohibition request flag F2,
The value of F3 is confirmed, and if either one is 1, the fourth gear 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 judged that the uphill judgment flag F0 is not zero, or even if it is judged that the flag F0 is zero, it is judged that the fourth speed prohibition request flag F2 for uphill is not one. If so, the process proceeds to step 134.

At step 134, the value of the first downhill road determination flag F1 is determined. Further, at step 136, it is judged if the fourth downshifting prohibition request flag F3 for downhill is 1 or not. When it is determined that the fourth downhill speed prohibition request flag F3 for downhill is 1 even though the first downhill determination flag F1 is zero, the routine proceeds to step 138, where the above-described downhill control return timer is set. It is judged whether or not it is finished, and if it is finished, in step 140, the fourth descending road
The speed prohibition request flag F3 is reset to zero.

However, the first descending slope determination flag F1
Is not zero, or even if it is zero
When the speed prohibition request flag F3 is not 1, and when 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 If either one of the speed prohibition request flags F2 and F3 is 1, the fourth speed is prohibited 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 the downhill road can be set to a relatively large value (first slope), and as a result, the low speed stage is unnecessarily required. It is possible to prevent the control of downshifting to be executed, and when the foot brake is operated within a predetermined time from the time when the accelerator is released, consider that the driver wants a sudden deceleration and Even when the vehicle is traveling on a road having a relatively small road gradient (second gradient), it is possible to reliably shift down to a low speed stage. As a result,
The true deceleration request of the driver 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, when the downhill road is judged while the uphill return timer is in operation, the threshold value of the road surface slope for the judgment is set low. Similarly, in the determination of an uphill road during the operation of the downhill return timer, the threshold value of the road surface slope for the determination is also set to be low. As a result, when traveling on a mountain road where uphill and downhill roads 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 determining the downhill road, and the downhill road is approached at the relatively large first slope unless special conditions are set. Therefore, if the control for decreasing the first slope 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, and once the normal control is performed. It is considered that there is a high possibility that a situation of returning to the above will occur, but such a situation can be prevented by the control for lowering the first gradient.

Further, according to this embodiment, as described above, the first gradient and the second gradient are changed so as to be larger in the high vehicle speed range and the low vehicle speed range than in the medium vehicle speed range, respectively. Since the setting is made, it is possible to prevent the downhill control from entering more than necessary at high vehicle speed and low vehicle speed.

Therefore, the acceleration itself is small due to the increase in the running resistance, and therefore the effect of the engine braking is small when the vehicle speed is high and it is not necessary to execute the downhill control so much. It is possible to prevent the vehicle from being downshifted to an undesirably low speed when the vehicle speed is not required.

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

[0096]

As described above, according to the present invention,
The thresholds for determining the uphill road when the downhill return timer is operating and the thresholds for determining the downhill road when the uphill return timer is operating are set to be lower than the thresholds when the respective return timers are not operating. Therefore, in a traveling state in which an uphill road and a downhill road are repeated, the uphill control and the downhill control can be smoothly continuously performed without going through the normal control, and as a result, the busy shift can be prevented. That is an excellent effect.

[Brief description of drawings]

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

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

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

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

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

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

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiharu Harada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (2)

[Claims] 1. When the vehicle is equipped with means for determining whether or not the vehicle is traveling on an uphill / downhill road, and when it is determined that the vehicle is traveling on the uphill / downhill road, a shift speed suitable for the uphill / downhill road is set and the uphill control is released. In a control device for an automatic transmission for a vehicle on an uphill / downhill road configured to release the uphill control after a lapse of a predetermined delay time, means for determining whether or not the current time point is within the delay time And a means for setting a threshold value of a road surface gradient, which is a criterion for judgment in the determination of the downhill road, to be smaller when the delay time is set than when the delay time is not set. A control device for an automatic transmission for a vehicle on a slope. 2. A means for determining whether or not the vehicle is traveling on an uphill / downhill road, and when it is determined that the vehicle is traveling on an uphill / downhill road, a shift speed suitable for the uphill / downhill road is set and downhill control is released. At this time, in a control device for an automatic transmission for a vehicle on an uphill / downhill road configured to cancel the downhill control after a predetermined delay time, it is determined whether or not the present time is within the delay time. And a means for setting the threshold value of the road surface gradient, which is a criterion for judgment in the determination of the uphill road, to be smaller during the delay time than when not in the delay time. A control device for an automatic transmission for a vehicle on a climbing slope.