JP3129089B2 - Control device for automatic transmission for vehicle on downhill 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 a 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] Further, in Japanese Patent Application Laid-Open No. 1-261545, when it is determined that the vehicle is traveling on a downhill, a speed suitable for the downhill (specifically, a speed at which engine braking is more effective) is determined. There is disclosed a technique for executing a descending slope control and canceling the descending slope control after a lapse of a delay time when it is detected that the accelerator is depressed. According to the same publication, the delay time is set when the downhill control is released at the moment when the accelerator is depressed, a shift-up may occur at the same time, and as a result, a shock or a sense of discomfort may be sensed. It is said to be.

[0007]

Generally, the accelerator work of a driver while traveling on a downhill road is when stepping on an accelerator to obtain traction when turning a corner, when moving from a downhill road to an uphill road. When the accelerator is depressed to increase the engine output, the accelerator is depressed for the purpose of accelerating on a downhill road with good visibility.

[0008] However, Japanese Patent Application Laid-Open No. Hei 1-26154 discloses the above.
According to the related art disclosed in Japanese Patent Application Laid-Open No. 2005-133, the downhill control is released after the fixed delay time has elapsed. Therefore, in a case where the delay time is set to be short, the downhill control is easily released. There is a problem that a busy shift (frequent shifts) occurs. On the other hand, if the delay time is set to be relatively long, the problem that the cancellation of the downhill control is delayed in such a case.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and more precisely monitors the accelerator work traveling on a downhill road so that the downhill control can be truly performed by the driver. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle on a downhill road which can be released so as to conform to a required driving mode.

[0010]

SUMMARY OF THE INVENTION As shown in FIG. 1, the present invention comprises means for determining whether or not the vehicle is traveling on a downhill road and means for detecting release of an accelerator. A downhill road for executing a downhill control for setting a gear suitable for the downhill road when it is determined that the vehicle is traveling, and releasing the downhill control after a delay time elapses when it is detected that the accelerator is depressed. In the control device of the automatic transmission for a vehicle in the means for detecting the accelerator opening, the delay time,
Rutotomoni accelerator opening and a delay time setting means for setting longer than when smaller is larger than a predetermined value,
The vehicle further includes means for detecting a vehicle speed.
The fixed value is larger when the vehicle speed is high than when the vehicle speed is low.
By setting , the above problem has been solved.

[0011]

In the case described above, that is, when the driver steps on the accelerator to obtain traction when turning a corner,
The depression of the accelerator is relatively small, and the depression time is short. Therefore, even if the delay time is short, there is a high possibility that the accelerator will be released again within that short time,
At this time, if the other conditions of the downhill control are continuously satisfied, the downhill control is continued without any trouble. On the other hand, when the other conditions of the downhill control are not satisfied, the return to the normal control is quick because the delay time is set short.

In such a case, that is, when the accelerator is stepped on to increase the engine output when shifting from a downhill to an uphill, the depression of the accelerator is relatively large. Therefore, when setting the delay time, by setting the delay time longer as the accelerator pedal is depressed, the condition of the ascending control can be determined within the longer delay time, and this is established. In this case, it is possible to shift from the downhill control to the uphill control without going through the normal control. As a result, a busy shift can be prevented.

That is, it is possible to appropriately set the delay time in the above-described case, and it is possible to prevent the occurrence of the busy shift and the delay in releasing the downhill control.

Further, in the above-mentioned case, that is, in the case of stepping on the accelerator to accelerate on a downhill road or the like with good visibility, when the accelerator opening is large, the accelerator opening is larger than when the accelerator opening is small. Since a good result is obtained qualitatively when the length is set long, the present invention functions well in such a case.

That is, when the vehicle is slightly accelerated on a downhill road or the like with good visibility, the accelerator is generally depressed. In this case, the gear stage (low speed stage) where the engine brake is more effective is maintained by the downhill control until then, but with the elapse of the shorter set delay time, the gear stage where the engine brake is weaker (high speed stage) )
Will be returned to.

When the accelerator is stepped on to increase the acceleration to a greater level than the current state, a longer delay time is set. However, when the accelerator is stepped on to accelerate, the downhill control was originally canceled. It is highly probable that the vehicle will be maintained at the low gear, and maintaining the low gear itself is consistent with the driver's intention and there is no problem. It is possible to prevent a re-shift down caused by stepping on from occurring in a short period of time, and it is also possible to continuously cope with an uphill road (without going through normal control). Can be reduced, so that good results can be obtained.

Further, contact to set this delay time, further consideration of the elements of the vehicle speed, the vehicle speed is so large sets a predetermined value (threshold value) of the accelerator opening than when low when high And better results are obtained. This is because, generally, the higher the vehicle speed, the greater the amount of depression of the accelerator in any of the above cases.

[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 immediately performed when a prerequisite condition of the uphill / downhill control described later is not satisfied. However, when the condition of the uphill road is not satisfied,
This is performed after a predetermined return timer has elapsed.

<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 first gradient that is relatively large and a second gradient that is smaller than the first gradient. Be prepared. Further, both the first gradient and the second gradient are changed and set depending on the vehicle speed. That is, in the high vehicle speed range and the low vehicle speed range, the first gradient and the second gradient themselves are set to have larger values than in the middle vehicle speed range, and more fine-grained control is performed.

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

That is, when the vehicle is traveling in 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 in the third speed, the vehicle is shifted up to the fourth speed as long as the conditions of the downhill road with a gradient greater than the first gradient, the accelerator release, and the foot brake on condition are maintained. 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.

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 performed only when the vehicle is running at the fourth speed with the accelerator pedal 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, it is possible to return to the third speed again by the control relating to the second gradient. do not do.

The reason is that the control according to the second gradient is executed to shift down again to the third speed until the gear is shifted up to the fourth speed with 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.

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

When the timer value of the return timer depends on the accelerator opening (corresponding to the throttle opening), when the accelerator opening is smaller than a predetermined threshold value θa, a relatively short time t is set.
0, and when it is larger than the threshold value θa, it is set to t1 longer than this.

Thus, for example, when the driver steps on the accelerator to obtain traction when turning a corner, the return timer is set to a short time t0 because the accelerator is generally depressed by a small amount. As a result, as described above, cancellation and continuation of the downhill control are rationally selected.

In the case where the accelerator is stepped on when shifting from a downhill to an uphill, when the accelerator is generally depressed by a large amount, the return timer is set to a longer time t1. As a result, it is possible to continuously shift from the downhill control to the direct uphill control without causing a busy shift.

Further, even when the accelerator is depressed to accelerate on a downhill road or the like with good visibility, the short timer t0 is set when the accelerator depression amount is small, and the long timer t1 is set when the accelerator depression amount is large. Therefore, qualitatively favorable results can be obtained as described above.

When the t0 timer, which is set when the accelerator opening is small, is in operation and the foot brake switch 88 is turned on, that is, when the foot brake is depressed, the t0 timer is detected. Is cleared, and counting up is restarted from the time when the foot brake switch 88 is switched from on to off again.

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 uphill and downhill roads. Specifically, 1) that the vehicle speed sensor 82 of the automatic transmission is normal, and 2) the shift position switch 86 is set as 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.

The condition that the vehicle speed is within the predetermined value in 4) is based on the condition that when the vehicle speed is equal to or lower than the predetermined value (out of the applicable range of the present control), the second speed stage or the first speed stage. 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.

The condition that the overdrive off switch is not operated in 5) is based on the condition that the driver is intentionally prevented from traveling in the overdrive (fourth speed), and this condition is not applied. 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 activated in 6) is based on the condition that when the cruise control is being 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, first, it is determined whether or not 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.

More 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. .

When it is determined that the road is 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 road is not an uphill road, the flow proceeds to step 108. Proceed to the flag F0
Is reset to zero.

At 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 set to zero in step 108, the flow proceeds to step 11
The program proceeds to step 200. Specifically, in step 200, it is determined whether or not the idle contact switch 92 is on, that is, whether or not 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).
(Gear, fourth gear) and a reference vehicle acceleration corrected for a slope threshold for a downhill road that is pre-mapped based on a first road surface slope (first slope) depending on the vehicle speed for each select pattern. (With positive or negative).

In other words, 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 small because the running resistance becomes large when the vehicle speed is high, but also that the vehicle speed is high. In the vehicle speed range and the low vehicle speed range, the first gradient itself is considered so as to be steeper 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 208, it is determined whether 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 return timer t described later starts counting up.

According to the above control flow, the determination of the downhill road with the first gradient as the threshold is executed. It is to be noted that the first gradient itself already has a characteristic depending on the vehicle speed, as described above.

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 (and for an uphill road) constituted by parameters of both the throttle opening and the vehicle speed, and KDGE is a predetermined value (only positive) for giving hysteresis. is there.

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 proceeds directly to step 222, where the second downhill road determination flag F10 is set to zero. Is reset to

Note that 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 relating to the second gradient is performed 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 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 downhill 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.

When the process reaches step 126 in this way,
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".

If 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 it is reset to a predetermined time. It is determined whether or not the uphill control return timer to be counted up has expired. If it has been completed, the fourth-speed uphill prohibition request flag F2 for ascending is reset to zero in step 132, but if it has not been completed, the process proceeds to step 142, where the fourth-speed upright prohibition request flag F2 for ascending is reset. The value is checked, and if the value is 1, the fourth speed is prohibited in step 146.

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". If 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 control returns to the downhill control described in detail later. It is determined whether or not the timer has expired. If the timer has expired, at step 140, the fourth-speed-stage-prohibition request flag F3 for a downhill road 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.

Here, more specific processing contents of the control relating to the return timer in steps 138 and 140 will be described with reference to FIG.

When the process proceeds to step 138, specifically, in step 400, a downhill return mode flag F5 indicating that the vehicle is returning to a downhill when the accelerator pedal depression amount is large.
Is determined to be zero. Since it is initially zero, the process proceeds to step 402, where a map of the threshold value θa of the accelerator opening (throttle opening) for setting the delay time is searched. This map is set in advance so as to increase as the vehicle speed increases, depending on the vehicle speed. Therefore, by applying the current vehicle speed to the map, the accelerator opening threshold value θa to be adopted is determined here.

In step 404, it is determined whether or not the accelerator opening θ is smaller than the threshold value θa. If it is smaller, the process proceeds to step 406, and as described above, whether the value of the timer t already counted up from the time when the first downhill determination flag F1 changes from 1 to 0 has reached the shorter delay time t0. Is determined. If not, the process proceeds to step 142 (see FIG. 4) to continue the downhill control,
When it is determined that the delay time t0 has been reached, step 4
At 16, the downhill return mode flag F5 is reset to zero,
In step 140 (see FIG. 4), the fourth-speed-gear prohibition request flag F3 for the downhill road is reset to zero.

On the other hand, if it is determined in step 404 that the accelerator opening θ is larger than θa, the flow proceeds to step 410, where the accelerator downgrade return mode flag F
5 is set to 1, and in step 412 the timer t is reset. That is, the timer t starts counting up anew. Thereafter, the delay time t1 set longer in step 414 is compared with the count value of the timer t. However, since it is initially determined that the timer t is smaller, the process proceeds to step 142 to continue downhill control. You.

[0091] flows from once next time the flag F5 is Ru is set to 1, the process proceeds from step 400 directly to 414, the count value of the timer t is (the longer) whether reaches the delay time t1 is determined. If not, the process proceeds to step 142 to continue the descending slope control. However, when it is determined that the delay time t1 has been reached, the descending slope return mode flag F5 is reset to zero in step 146, and in step 140, the descending slope control mode flag F5 is reset. The fourth-speed-gear prohibition request flag F3 is reset to zero .

By the control flow as described above, the control of the downhill road as described above is realized before the concrete description of the control flow.

According to this embodiment, the delay time set when the downhill control is released by releasing the accelerator is set to be short when the depression amount of the accelerator is small and long when the depression amount of the accelerator is large. As a result, the downhill control and the normal control or the uphill control are repeated more than necessary, and as a result, it is possible to effectively prevent the occurrence of the busy shift and to make the downhill control no longer necessary. In such a situation, it is possible to quickly shift to the normal control.

Further, 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), and as a result, the threshold value becomes unnecessarily large. It is possible to prevent the control for shifting down to the low gear to be executed, and when the foot brake is operated within a predetermined time from the time when the accelerator is released, it is considered that the driver wants rapid deceleration. Thus, even when the vehicle is traveling on a road having a relatively small road gradient (second gradient), it is possible to surely shift down to the 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, according to this embodiment, as described above, the first gradient and the second gradient are changed to values larger in the high vehicle speed range and the low vehicle speed range than in the middle vehicle speed range.
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. 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 deceleration request 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.

[0097]

As described above, according to the present invention, in a situation in which the running state is expected to again enter the downhill control (or uphill control), the downhill control is canceled (normal control). Return to) can be delayed. As a result, it is possible to effectively prevent the occurrence of the busy shift due to the frequent switching of the downhill control, the normal control, or the uphill control.

On the other hand, when it is determined that the traveling state no longer requires the downhill control, an effect is obtained that the normal control can be quickly returned to.

[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 110 in FIG. 4;

FIG. 6 is a flowchart showing details of step 138 of 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 the front page (72) Inventor Yoshiharu Harada 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-64-49747 (JP, A) Real-life Sho-63-18659 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 61/00-61/24

Claims (1)

(57) [Claims] Means for determining whether or not the vehicle is traveling on a downhill road;
Means for detecting the release of the accelerator, and performing downhill control to set a gear suitable for the downhill road when it is determined that the vehicle is traveling on a downhill road, and when it is detected that the accelerator pedal is depressed. In the control device for an automatic transmission for a vehicle on a downhill road that releases the downhill control after a delay time has elapsed, a means for detecting an accelerator opening, and the delay time is set when the accelerator opening is smaller than a predetermined value. Rutotomoni and a delay time setting means for setting a longer, further comprising means for detecting a vehicle speed, at said accelerator opening
The fixed value is larger when the vehicle speed is high than when the vehicle speed is low.
Setting control device for an automatic transmission for a vehicle in the downhill characterized by.