JP6035515B2 - Control method for automatic transmission of vehicle - Google Patents

Description

The present invention relates to a method for controlling an automatic transmission of a vehicle that can simultaneously solve the problem of ensuring good drivability and reducing the amount of heat generated by a clutch on an uphill road.

In an automatic transmission of a vehicle, the clutch generates heat during shifting. If this amount of heat generation exceeds a certain amount, the clutch is over-permissible, and problems such as clutch burn-in occur. In particular, there is a so-called “jumping shift” in which a large amount of heat is generated in one shift, and so-called “jump shift” is performed at a stroke.

In particular, it is remarkable when driving on an uphill road having a curve and repeatedly turning on and off by “jumping speed change”. For example, after shifting from the 3rd speed to the 1st speed (hereinafter referred to as [3 → 1] shift), the [1 → 3] shift is performed so that the shift is returned to the original 3rd speed by loosening the accelerator. The amount of heat generated by the clutch is remarkably large when the vehicle is executed and then the accelerator is depressed and the operation is shifted to the [3 → 1] speed change again.

Conventionally, Patent Document 1 discloses a shift control method for restricting “jump shift” in an automatic transmission so as to protect the clutch by reducing the amount of heat generated by the clutch at the “jump shift”. Specifically, Patent Document 1 discloses a method of controlling so as not to permit the jump shift when the clutch heat generation amount is severe when the reverse jump shift is determined.

However, in the case of the shift control method disclosed in Patent Document 1, a map is prepared that defines a range in which jump shift is allowed in the relationship between the vehicle speed and the engine output torque, and the reverse jump shift cannot be performed unless it is within the allowable range based on this map. Even if the amount of heat generated is within the allowable range, the reverse jump shift can be executed, and the jump shift itself is performed even outside the allowable range (reverse rotation may be restricted). . Therefore, it can be said that the regulation of the amount of heat generated by the clutch by “jumping shift” is incomplete.

On the other hand, “jumping speed change” is useful as a means for ensuring good driving ability (hereinafter referred to as “drivability”), and it is not preferable to restrict “jumping speed change” unnecessarily.

Japanese Patent No. 496882

The present invention has been created in view of the above problems, and is a vehicle that regulates "jumping speed change" so as to ensure good drivability while sufficiently reducing the amount of heat generated by a clutch on an uphill road having a curve. An object is to provide a shift control method for an automatic transmission.

The present invention provides a shift control method for an automatic transmission of a vehicle. In particular,
The speed change control method includes climbing road determination means for determining whether the road on which the vehicle is traveling is an uphill road and corner determination means for determining whether the road is a road with many corners. When it is determined that the road is an uphill road by the uphill road determination unit and the road is determined to be a road with many corners by the corner determination unit, the jump shift after both determinations is prohibited.

In the shift control method for an automatic transmission of a vehicle according to the present invention, attention is paid to “jump shift” on an uphill road as a situation where the amount of heat generated by the clutch is particularly large. The inventor has learned that the amount of heat generated by the clutch during the “jumping shift” on the road where power on / off is repeated, that is, the road with many corners, among the “jumping shift” on this uphill road is large. Therefore, it has been found that in order to sufficiently reduce the amount of heat generated by the clutch on the uphill road, it is only necessary to regulate “jumping speed change” during road driving with many corners. On the other hand, since the “jumping speed change” is not restricted on the uphill roads other than the uphill road with many corners, it is possible to minimize the drivability trouble as a whole on the uphill road.

In other words, the present invention is advantageous in that the problem of “drivability” and “clutch heat generation” can be solved at the same time by restricting “jump shift” under the limited condition that there are many uphill roads and corners. It is. In addition, since the amount of heat generated by the clutch can be reduced, as a result, the life of the clutch can be improved.

An automatic shift diagram in the D range is shown. In the control method of the present invention, there is shown an example of a graph showing the turbine rotational speed in a time series when the jump speed is restricted on a road surface with many corners on an uphill road. An example of a graph showing time-series turbine rotational speeds before and after the release of control in the present speed change control method is shown. It is the determination flowchart of the start condition and cancellation | release condition.

As a premise for explaining the shift control method of the automatic transmission of the present invention, first, so-called “jump shift” will be mentioned.
FIG. 1 shows an example of an automatic shift diagram in the D range (hereinafter also simply referred to as “shift diagram”). In the shift diagram of FIG. 1, a shift diagram in the first to third speed regions is shown. Specifically, downshift diagram from 2nd to 1st gear (2 → 1 diagram), upshift diagram from 1st gear to 2nd gear (1 → 2 diagram) and 3rd gear to 2nd gear A downshift diagram (3 → 2 diagram) is shown. In FIG. 1, the vertical axis indicates the slot opening, and the horizontal axis indicates the vehicle speed v.

If the throttle is fully opened (7/8 or more open) by stepping on the accelerator while the automatic transmission is in the 3rd speed range, the point (1) starting arrow in the shift diagram of FIG. It can be seen that the end point is point (2) across the 2 → 1 diagram. In this case, the gear is shifted down from the third speed to the second speed. Such a shift that shifts down or up from a high shift stage at a time is referred to as “jump shift”. Here, it is shown that [3 → 1] shift is executed as “jump shift”. At this time, as indicated by the arrow starting from the point (2), the vehicle speed v rises from the time v = v1 when the accelerator is stepped on and reaches v = v2, and the [3 → 1] shift ends (end point (3 )reference). Such shift control is referred to as “jumping shift”.

Further, this “jumping shift” may be repeated. For example, if the accelerator is loosened before the [3 → 1] shift is completed, the original third speed is restored. Conventionally, the “jump shift” in the upshift is prohibited because of the large amount of heat generated by the clutch. Once the [3 → 1] shift is completed, [3 → 2] and [2 → 1]. The gears are shifted in order, but if the shift is stopped in the middle of [3 → 1] shift, the original shift stage is restored. At this time, as shown from the start point (3) to the end point (4) in FIG. 1, if the [3 → 1] shift is restored before the end, the [1 → 3] shift is executed and the vehicle speed v is constant. It is. When the accelerator is stepped on again and the slot is fully opened, the “jumping speed change” is made again from the third speed to the first speed (see the start point (4) to the end point (5)), and the vehicle speed v increases from v2 to v3 (end point ( 6)). Then, after the point (6), during the [3 → 1] shift, and when the accelerator is loosened, the speed is returned to the third speed. In this manner, the actual “jump shift” at the upshift stage from the start point (3) to the end point (4) and after the point (6) is repeated many times.

Such a phenomenon in which the “jump shift” (“similar to the jump shift”) is repeated during the upshift typically occurs during traveling on an uphill road having a curve. This is because in the case of an uphill road having a corner, the accelerator is returned and braked at the corner entrance, and the power on / off is repeated such that the accelerator is depressed toward the corner exit. On the other hand, even if it is the same uphill road, it does not occur in the case of a single road without a curve. In the case of a single road, once the accelerator is depressed, it is not necessary to return or depress the accelerator until the end of the uphill road. Therefore, in the present invention, in order to sufficiently reduce the amount of heat generated by the clutch on the uphill road, the “jumping shift” is restricted only during traveling on a road with many corners.

Therefore, in the shift control method of the automatic transmission, first, it is determined whether the road is an uphill road using a gradient sensor or the like, and an uphill road with many corners is determined using a rudder angle sensor or the like. When it is determined that the road surface is an uphill road and has many corners, control is performed so as to prohibit the subsequent jump shift. FIG. 2 shows an example of a graph showing the turbine rotational speed in a time series when the jumping speed is restricted on a road surface with many corners of an uphill road in the control method of the present invention.

First, when the accelerator is depressed during traveling in the third speed region and a command to fully open the throttle is transmitted, a [3 → 1] shift command is transmitted to the automatic transmission (time t = t0). At this time, the turbine speed increases and the vehicle speed increases. If it is an uphill road, it is determined that the gradient sensor is an uphill road (time t = th). This determination is the “first requirement” for starting the jump shift prohibition control. Next, the accelerator is released before the end of [3 → 1] shift (time t = t1). When the accelerator is loosened, a [1 → 3] shift is executed to return to the original third speed, and the turbine speed is also reduced (time t = t1 to t2). When the shift is completed, the third speed region is maintained (time t = t2 to t3).

Next, when the accelerator is depressed again (time t = t3), the jump shift of [3 → 1] is executed again like the times t0 to t1, and the accelerator is released again until the end of [3 → 1] shift. Similarly, [1 → 3] shift is executed (time t = t4 to t5). In the middle of the time tc, the rudder angle sensor determines that the road surface traveling has many corners. This determination is performed when the rudder angle sensor detects a rudder angle variation of a predetermined value and a predetermined number of times or more during a predetermined time. This determination is the “second requirement” for starting the jump shift prohibition control. When both the “second requirement” and the “first condition” are satisfied, control is performed so as to prohibit “jump shift” thereafter (after time tc).

Therefore, after the time tc when the jump shift is prohibited, the [3 → 1] shift is executed even when the accelerator is depressed again from the third speed region and the throttle fully open command is transmitted (time t = t6). First, after [3 → 2] shift is performed (time t = t6 to t7), [2 → 1] shift is executed (time t = t7 to t8).

Furthermore, if the accelerator is released again before the end of [2 → 1] (time t8), “jumping speed change” is also prohibited here, and after [1 → 2] is changed (time t = t8 to t9). , [2 → 3] shift is executed (time t = t9 to t10).

Next, conditions for canceling the speed change control method will be described. FIG. 3 shows an example of a graph showing the turbine rotation speed before and after the cancellation of control in this shift control method in time series.
In FIG. 3, first, the vehicle travels in the third speed region in a state where the jump shift prohibition control is continued.

Therefore, when the accelerator is depressed at time t11 and the throttle fully open command is transmitted, [3 → 1] jump shift is not executed, and after [3 → 2] shift is sequentially performed step by step (time t = t11 to 11). t12), [2 → 1] shift is executed (time t = t12 to t13). Then, as in FIG. 2, if the accelerator is released before the end of [2 → 1] (time t13), “jumping speed change” is also prohibited here, and after [1 → 2] is changed (time t = t13). To t14), [2 → 3] shift is executed (time t = t14 to t15), and the third speed region is maintained (t = t15 to t16).

In the case of the example in FIG. 3, it is determined that the uphill road has ended at time tnh in the middle of time t15 to t16 during traveling in the third speed region. This determination uses the same gradient sensor as that for the uphill road determination, and this determination is a requirement for canceling the final shift prohibition control. Here, the end of the uphill road is detected by a gradient sensor as a release requirement. However, the release condition is when the change in the rudder angle falls below a predetermined value by the rudder angle sensor used in the above corner determination. And so on.

Next, when a command is issued again to depress the accelerator and the throttle is fully opened, the prohibition of jump shift is canceled and a [3 → 1] shift command is transmitted (time t = t16). Then, when the accelerator is loosened before the end of [3 → 1] shifting through the increase in the turbine speed and the increase in vehicle speed (time t17), the speed is returned to the third speed. Although not shown, when the accelerator is loosened after the [3 → 1] shift, the [2 → 3] shift is executed after the [1 → 2] shift.

Heretofore, the start condition and the release condition of the jump shift prohibition control in the present shift control method have been described. Hereinafter, the determination flow of the start condition and the release condition will be described with reference to FIG. First, during the traveling of the vehicle, the gradient angle θ (°) is always measured by the gradient sensor (STEP 10). At the same time, the steering angle λ (°) of the vehicle is measured by the steering angle sensor (STEP 12). It is always determined whether the gradient θ is equal to or greater than a predetermined angle (θ ≧ α) (STEP 14). When θ> α, the road surface slope is not so large and it is determined that the road surface is normal. On the other hand, when θ ≧ α, it is determined that the road is an uphill road. This is the first condition among the start conditions.

In the case of an uphill road, the number n of times that the steering angle λ becomes equal to or greater than the predetermined angle β (°) within a predetermined time is measured (STEP 16). Then, it is determined that a road surface in which a steering operation of a steering angle β (°) or more is repeated a plurality of times within a certain time is a road with many corners and is traveling with a heavy power on / off. When the number n of times equal to or greater than the predetermined angle β is greater than the predetermined number N, the “jumping shift” until the release condition is satisfied is prohibited thereafter (STEP 20). This is the second condition among the start conditions, and constitutes the start condition together with the first condition described above.

Thereafter, the “jumping speed change” prohibition control is continued until it is not a climbing road and becomes a normal road. When it is determined that the road surface gradient θ is again smaller than the predetermined angle α (STEP 22), the release condition is satisfied and “jumping speed change” is possible.
In FIG. 4, the cancellation condition is assumed to be gradient θ <α (= same as the start condition), but the gradient angle serving as the cancellation condition may be set smaller than α which is the start condition. In addition, as described above, it may be determined that the number of corners on the road surface has decreased when the change in the steering angle λ becomes a predetermined number of times or less as the release condition.

The embodiment and the concept of the shift control method of the automatic transmission according to the present invention have been described above. However, the present invention is not limited to this, and the spirit and teaching described in the claims and the specification are described. Those skilled in the art will understand that other modifications and improvements can be obtained without departing from the scope.

For example, the description in the above embodiment shows an example of the control configuration in the case where the throttle is fully opened from the third speed region and “jump shift” is performed to the first speed. This also applies to “jumping speed change”. In the above embodiment, only the shift from the third speed to the first speed is illustrated, but the present invention is actually applied to a [4 → 2] shift and a [5 → 3] shift.

Claims (1)

A method for controlling an automatic transmission of a vehicle,
The road on which the vehicle runs is
An uphill judging means for judging whether the road is uphill,
Corner judging means for judging whether or not the road has many corners,
An automatic transmission characterized in that, when it is determined that the road is an uphill road by the climbing road determination means and the road is determined to be a road with many corners by the corner determination means, a jump shift after both determinations is prohibited. Control method.