JPH09229185A - Control device of automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rapid increase of the output shaft torque by quick down- shifting when an automatic transmission is changed over from the manual mode into the Auto mode. SOLUTION: Judgement is made whether or not a down-shift exceeding a specified level is made (S4 and S5) in case the shift conforming to a shift map in the Auto mode is executed as it is, in the initial time of changing over from the manual mode to the Auto mode (S1 and S3). When the down-shift is to exceed the specified level, a stepping down-shift is introduced from the gear position in the manual mode to the gear position requested by the shift map in priority to the shift control conforming to the shift map so that a quick down-shift is avoided (S7).

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, and more specifically, it switches from a state in which a gear position or a torque ratio is arbitrarily selected (manual mode) to a state in which it is automatically selected (auto mode). TECHNICAL FIELD The present invention relates to a technique for avoiding a sudden change in output shaft torque when being driven.

[0002]

2. Description of the Related Art Conventionally, there are provided a manual mode in which a gear position or torque ratio in a transmission can be arbitrarily selected, and an automatic mode in which the gear position or torque ratio is determined according to a preset schedule. 2. Description of the Related Art There is known an automatic transmission configured so that a driver can arbitrarily switch modes (see Japanese Patent Laid-Open Nos. 7-83322 and 6-74318).

[0003]

By the way, in the manual mode, a gear position or torque ratio completely different from the schedule in the automatic mode can be arbitrarily selected. Therefore, when the manual mode is switched to the automatic mode, a predetermined value or more is exceeded. Is downshifted, which causes a sudden change in the output shaft torque.

For example, in the auto mode, under the condition where the vehicle speed is low such that the first speed is selected and the accelerator is fully opened (see FIG.
If the 4th speed is selected in the manual mode and the mode is switched from this state to the auto mode, the 1st speed is selected in the auto mode. As a result, the 4th speed is changed to the 1st speed. There was a fear that the output shaft torque would suddenly increase due to the downshift (see Fig. 15).

The present invention has been made in view of the above problems, and an object of the present invention is to reliably prevent a sudden increase in the output shaft torque when the manual mode is switched to the automatic mode.

[0006]

Therefore, the invention according to claim 1 is constructed as shown in FIG. In FIG. 1, the manual mode is a mode in which the gear position or torque ratio in the transmission can be arbitrarily selected, and the auto mode is a mode in which the gear position or torque ratio in the transmission is determined according to a preset schedule. One of these modes can be arbitrarily selected by the mode selection means.

Here, the output shaft torque change suppressing means is provided for the transmission associated with the downshift when the downshift is performed at a predetermined level or more when the manual mode is switched to the automatic mode by the mode selecting means. Forcibly suppresses increase changes in output shaft torque. According to such a configuration, when the manual mode is switched to the automatic mode, if the gear position or torque ratio selected in the manual mode is changed to the gear position or torque ratio determined in the automatic mode, a predetermined value or more is obtained. In the case of downshifting, control for suppressing the output shaft torque is executed so that the output shaft torque does not suddenly increase with the mode switching.

For example, under the condition of low vehicle speed such that the first speed is selected in the auto mode and the accelerator is fully opened (see FIG. 4).
If the gear position for the 4th speed is selected in the manual mode, the downshift from the 4th speed to the 1st speed normally results in a sudden output shaft torque when switching to the automatic mode. Therefore, under such conditions, control for suppressing an increase in output shaft torque is executed to prevent a sudden change in output shaft torque during mode switching.

In practice, an increase in the output shaft torque is suppressed by avoiding a sudden downshift or by controlling the engine output torque so as to offset the sudden increase in the output shaft torque due to the abrupt downshift. become. According to a second aspect of the invention, the output shaft torque change suppressing means is
Based on the gear position or torque ratio to be determined according to the automatic mode and the gear position or torque ratio in the manual mode before switching when the manual mode is switched to the automatic mode by the mode selection means, a predetermined value or more The configuration is such that it is determined whether or not the condition is that the downshift is performed.

With this configuration, when the mode is switched to the automatic mode, the downshift amount when the shift is actually performed in accordance with the automatic mode is predicted. For example, in the above example, the downshift from the 4th speed to the 1st speed is performed. It can be determined in advance that the shift will be performed. In the invention according to claim 3, the output shaft torque change suppressing means gradually changes from the gear position or torque ratio in the manual mode before switching to the gear position or torque ratio determined according to the auto mode. The configuration is such that an increase change in output shaft torque is suppressed.

According to this structure, when the gear shift or the torque ratio determined in the automatic mode causes a downshift of a predetermined value or more, the gear position or the torque ratio in the manual mode before the switching is changed from the gear position or the torque ratio. Instead of stepwise changing to the gear position or torque ratio determined by the mode, it is gradually changed from the time of mode switching to the gear position or torque ratio determined by the auto mode. For example, in the example above, 4 to 1
In the present invention, where the gear is downshifted stepwise, for example, 4th gear → 3rd gear → 2nd gear → 1st gear (or 4th gear → 2nd gear)
The speed is gradually downshifted by temporarily shifting to an intermediate shift stage (speed → first speed, etc.).

According to a fourth aspect of the invention, the output shaft torque change suppressing means forcibly controls the output torque of the engine in a direction of suppressing an increase change in the output shaft torque due to the downshift. According to such a configuration, a downshift of a predetermined amount or more is performed in accordance with the mode switching, and when the output shaft torque is about to rapidly increase due to the downshift, the output torque of the engine is reduced to cause the downshift. The increase in output shaft torque is offset, and the sudden increase in output shaft torque is suppressed.

According to a fifth aspect of the present invention, the output shaft torque change suppressing means reduces the output torque of the engine by a predetermined value at the same time as the downshift accompanying the mode switching, and then gradually reduces the torque down amount of the engine. The output shaft torque is gradually increased. With such a configuration, the stepwise engine output torque down control that is performed simultaneously with the mode switching cancels the increase in the output shaft torque due to the downshift, and the original output shaft torque is reduced as the torque down amount decreases thereafter. Will gradually approach.

According to a sixth aspect of the invention, the output shaft torque change suppressing means changes the amount of suppressing the increase change of the output shaft torque according to the parameter indicating the driver's driving intention. According to such a configuration, the amount of suppression of the output shaft torque is changed according to the driver's driving intention, specifically, the degree of allowable increase in the output shaft torque, and for example, the driver's power performance demand is high. In this case, the amount of suppression of the output shaft torque is reduced to allow a relatively large increase in the output shaft torque.

According to a seventh aspect of the invention, the output shaft torque change suppressing means is configured to gradually increase and change the output shaft torque at a changing speed according to a parameter indicating a driver's driving intention. According to such a configuration, the amount of suppression of the output shaft torque is changed depending on the driving intention of the driver, specifically, whether the output shaft torque is desired to change smoothly or the output shaft torque is changed promptly. For example, when the driver desires a rapid change in the output shaft torque, the change speed of the output shaft torque is made relatively large.

According to an eighth aspect of the invention, the parameter indicating the driver's driving intention is set based on at least one of the accelerator operation speed and the accelerator operation amount. According to such a configuration, in general, the slower the accelerator operating speed and the smaller the accelerator operating amount, the lower the degree of power performance requirement of the driver, and therefore the smoother and smaller change in the output shaft torque. To be judged.

[0017]

Embodiments of the present invention will be described below. FIG. 2 is a system block diagram showing the power system of the vehicle in the embodiment, and the output of the engine 1 is transmitted to the drive wheels (not shown) via the transmission 2.

The transmission 2 may be either a stepped transmission such as a planetary gear type or a continuously variable transmission such as a pulley type or a toroidal type. Here, it is supplied from a hydraulic circuit 3. The gear position or torque ratio is controlled by the control oil pressure. The A / T control unit 4 adjusts the hydraulic pressure in each hydraulic path arranged inside the hydraulic circuit 3 by controlling the opening and closing of various electromagnetic valves (not shown) to adjust the gear position or torque in the transmission 2. Control the ratio to the target value.

On the other hand, an ENG control unit 5 for controlling the engine 1 is provided, and the ENG control unit 5 determines the ignition timing by the spark plug and the fuel injection valve based on the detection result of the engine load, the engine rotation and the like. Control the fuel injection amount. An engine rotation signal, a vehicle speed signal, an accelerator opening signal, etc. are input to the A / T control unit 4, while a select position signal of a select lever 6 operated by a driver is input.

The select position of the select lever 6 is
As shown in FIG. 2, common "P, R, N, D, 3,
In addition to "2,1", there is a manual position consisting of "+" and "-". Gate 7 (auto mode gate) of "P, R, N, D, 3, 2, 1" and the "+" and "-"
Gate 8 (manual mode gate) consisting of
It is provided in parallel through the switching gate 9,
When the shift lever 6 is shifted to the "D" range and the shift lever is tilted to the left side in the figure, the gate 8 can be moved to the manual position (mode selecting means).

In the "D" range, the A / T control unit 4 automatically determines the gear position or the torque ratio according to a predetermined shift schedule (see FIG. 4) according to the vehicle speed and the accelerator opening, for example. Although gear shifting is performed (auto mode), in the manual position (manual mode) that can be selected by moving the shift lever 6 from the "D" range, the A / T control unit 4 follows the driver's upshift or downshift instruction. Since the gear position or the torque ratio is controlled, the driver can arbitrarily select the gear position or the torque ratio.

That is, in the manual position gate 8, the select lever 6 is always kept in the neutral position between "+" and "-" (position capable of returning to the "D" range) by the biasing force of the spring. When the driver pushes the select lever 6 toward the front “+”, this is detected as an upshift instruction and an upshift is performed. On the contrary, the driver moves the select lever 6 to the front “−”. When pulled down, this is detected as a downshift instruction and downshift is performed.

The manner of shift control by the A / T control unit 4 in the automatic transmission 2 having the manual mode and the automatic mode as described above will now be described with reference to the flowchart of FIG. First, step 1
(Indicated as S1 in the figure. The same applies hereinafter), it is determined whether or not the manual mode is selected. If the manual mode is selected, the process proceeds to step 2 and the up operation is normally performed by the select lever 6. The shift control (manual mode) according to the shift / downshift instruction is executed.

On the other hand, when the automatic mode is selected instead of the manual mode, the process proceeds to step 3 and it is determined whether or not the manual mode was the previous execution of this routine, thereby switching from the manual mode to the automatic mode. It is determined whether or not it is the first time. Here, when the previous selection mode is not the manual mode but the automatic mode is continuously selected, the process proceeds to step 6 to execute the automatic shift in the automatic mode according to the normal shift schedule. If it is the first time that the manual mode is switched to the automatic mode (D range), the process proceeds to step 4.

In step 4, the shift map (shift schedule) in the automatic mode (D range) is searched, and the gear position (in the case of a stepped transmission) or the torque ratio (in the continuously variable transmission) to be determined in the automatic mode. If you ask). For example, a planetary gear type stepped transmission is provided with a shift map (shift schedule) in which the gear position is determined in advance according to the vehicle speed and the accelerator opening, as shown in FIG. Based on the current vehicle speed and accelerator opening, the gear position is searched.

Incidentally, in the case of a continuously variable transmission, a map in which a basic gear ratio (basic torque ratio) is determined based on a vehicle speed and an accelerator opening is provided, and an actual gear ratio (torque ratio) is set to a predetermined value. The basic speed ratio is controlled so as to gradually approach the basic speed ratio at the speed change speed, and thus the basic speed ratio corresponds to the torque ratio that should be determined in the automatic mode in the continuously variable transmission.

In the next step 5, the current gear position or torque ratio arbitrarily selected by the driver in the manual mode is compared with the gear position or torque ratio to be determined in the auto mode obtained in step 4. Then, it is determined whether or not the downshift is not less than a predetermined value when the gear is normally shifted according to the gear position or the torque ratio to be determined in the auto mode.

In the case of a step-variable transmission, the above-mentioned downshift is a case in which a downshift is performed by skipping a plurality of gears, for example, from the fourth speed to the first speed, and in the case of a continuously variable transmission. Then, the case where the change of the torque ratio (gear ratio) is equal to or larger than a predetermined value is shown. Here, when it is determined that the downshift does not exceed the predetermined value, from the gear position or the torque ratio selected in the manual mode,
Even if the gear position or torque ratio determined by the auto mode is directly controlled, it is estimated that the increase change in the output shaft torque of the transmission is sufficiently small. Immediately execute the automatic shift control of.

On the other hand, when it is determined that the downshift is more than the predetermined value, the gear position or torque ratio selected in the manual mode is directly changed to the gear position or torque ratio determined in the automatic mode. There is a fear that the output shaft torque will suddenly increase and the drivability will deteriorate and the driver will feel uncomfortable. Therefore, when it is determined that the downshift is more than the predetermined value, the smooth torque up control of step 7 is executed to forcibly suppress the sudden increase in the output shaft torque. The part of step 7 corresponds to the output shaft torque change suppressing means.

The contents of the smooth torque up control (output shaft torque change suppressing means) in step 7 are shown in FIG.
Is shown in the flowchart of FIG. Here, before giving a detailed description according to the flowchart of FIG. 5, an outline of the smooth torque up control will be described. As the smooth torque up control, one of the following two methods is executed. However, the configuration may be such that both are executed simultaneously.

In the first method, the gear position or torque ratio selected in the manual mode is not stepped down to the gear position or torque ratio determined in the automatic mode, but selected in the manual mode. The control that suppresses the sudden increase of the output shaft torque by gradually changing from the gear position or torque ratio that has been performed to the gear position or torque ratio determined in the auto mode, and gradually performing the downshift (hereinafter , Referred to as smooth torque increase by gear shift control).

In the second method, instead of directly downshifting according to the gear position or torque ratio determined in the automatic mode, the output torque of the engine is controlled to be forcedly down, and the output shaft by the sudden downshift is performed. This is a control in which an increase in torque is offset by a decrease in output torque of the engine to suppress a sudden increase in output shaft torque (hereinafter referred to as smooth torque increase by the engine).

By executing the first or second method described above, the output shaft torque of the transmission rapidly increases even when a large downshift is required when switching from the manual mode to the automatic mode. This can be avoided, and thus the driver is not uncomfortable and the drivability is improved. Further, in the smooth torque increase by the shift control, it is only necessary to change the shift control pattern, and it is not necessary to add hardware, so that it is possible to suppress a rapid increase in the output shaft torque at the time of mode switching with a simple configuration.

On the other hand, in smooth torque up by the engine, it is possible to suppress a sudden increase in output shaft torque while performing a rapid downshift. Next, details of the smooth torque up control will be described with reference to the flowchart of FIG. First, in step 21, it is determined whether or not this is the first execution of this routine.

If it is the first time, the process proceeds to step 22 to step 24 to perform the initial setting. In step 22, the torque reduction amount is decided. Specifically, in the case of performing a smooth torque increase by the shift control,
When the transmission 2 is a stepped transmission, the number of gears that allows downshifting is set by one shift operation. For example, when 2 steps is selected as the number of steps, 5th speed → 3rd speed →
As in the case of the first speed, it is assumed that a downshift over one step is allowed (see FIG. 6 (B)), and the number of steps is one.
If it is a tier, like 5th speed → 4th speed → 3rd speed → 2nd speed → 1st speed,
It is assumed that the interlaced downshifts are not performed and the downshifts are sequentially performed step by step (see FIG. 6A).

It is preferable that the number of steps allowed for the downshift is varied depending on the driving intention of the driver, specifically, the power performance requirement. In other words, when the driver desires high power performance by shifting with good followability, the first stage or two
While the interlaced downshift of the gears should be allowed, when the driver desires a shift that is smoother than the power performance, the interlocked downshift should be performed one by one without performing the interlaced downshift. .

Therefore, in accordance with the driver's driving intention (power performance requirement), there is provided a map as shown in FIG. 7 in which the number of steps allowed for downshifting in one shift operation is stored. It is a configuration to decide. Figure 7
In the case of (1), if the degree of power performance demand of the driver is high, the number of steps allowing downshift is set to be larger, and downshift involving a relatively large gear position or torque ratio change is allowed.

That is, the gear position selected in the manual mode is the fifth speed, and the required gear position in the automatic mode is 1.
When the allowable downshift stage number is set to 2 because the degree of power performance requirement is relatively high in the case of the high speed, the shift from the 5th speed to the 1st speed is made to the 5th speed → the 3rd speed → the 1st speed. As a result, a rapid torque increase can be suppressed (see FIG. 6B). On the other hand, if the driver's power performance requirement is low, the number of downshift-allowed steps is smaller, and the downshift is finer accordingly. For example, if the allowable downshift step number is set to 1, the fifth speed is set. The place where the gear is shifted to the 1st speed is changed to the 5th speed → the 4th speed → the 3rd speed → the 2nd speed → the 1st speed to suppress the rapid torque increase (see FIG. 6A).

Therefore, when the driver's degree of power performance requirement is low, the amount of torque increase by one shift operation is smaller than that in the case of high degree of power performance requirement.
The torque reduction amount with respect to the torque change in the case of stepwise changing from the 5th speed to the 1st speed has a larger value as the degree of demand for power performance is lower (see FIGS. 6A and 6B). The driving intention (power performance requirement) of the driver can be obtained from the accelerator operation speed or the accelerator operation amount.

For example, the maximum value of the accelerator operation speed or the accelerator operation amount is stored, and the stored data of the maximum value is sequentially compared with the latest detected operation speed or operation amount to update the maximum value. On the other hand, by attenuating the stored data of the maximum value, the stored data of the maximum value is gradually reduced when the operation speed or the operation amount is decreased, and the stored data of the maximum value is set to the driver's power. It can be used as a parameter indicating the degree of performance requirement.

When obtaining the accelerator operation speed, it is preferable to use the absolute value of the operation speed so that the driver's intention is obtained from both the speed on the stepping side and the speed on the returning side.
Further, when the maximum value of the accelerator operation amount is used as the parameter indicating the driver's driving intention, it is preferable to perform the correction based on the accelerator operation speed. A block diagram of FIG. 16 shows a method of obtaining the driving intention (power performance requirement) of the driver based on the accelerator operation speed.

In the block diagram of FIG. 16, the accelerator opening (accelerator operation amount) signal from the accelerator opening sensor 51 is differentiated in the differential operation section 81 to obtain the accelerator operation speed. The accelerator operation speed is obtained as a positive value on the accelerator side and a negative value on the accelerator return side. Therefore, the accelerator return speed is also detected as a parameter indicating the degree of demand for power performance of the driver.

The accelerator operating speed which can take a plus or minus value is converted into an absolute value by the conversion table 82, but the conversion characteristic of the operating speed on the plus side and the conversion characteristic of the operating speed on the minus side are made different. Even if the absolute value before conversion is the same, the operation speed on the negative side is
It is designed to be converted to a value smaller than the operation speed on the plus side. This is because the assisting force of the spring works on the return side (the operation speed on the minus side), and the driver's power performance request can be correctly determined by discounting the determination than by the stepping-in side.

The maximum value of the accelerator operation speed obtained as an absolute value is stored in the peak hold unit 83. The peak hold unit 83 compares the stored maximum value up to the previous time with the latest detected accelerator operation speed, and if the latest operation speed is higher than the stored value, the latest operation speed. Is stored as the maximum value while the stored maximum value is larger than the latest value, the stored value is held as it is.

Here, the attenuation processing unit 84 reads the maximum value stored in the peak hold unit 83, and gradually attenuates the maximum value based on a predetermined attenuation amount every unit time. The maximum value after the damping process is output to the power performance requirement degree setting unit 86, while the stored data of the maximum value in the peak hold unit 83 is updated and set based on the maximum value after the damping process. Therefore, in the peak hold unit 83, the stored data of the maximum value that is gradually attenuated is compared with the latest operation speed to update the stored data of the maximum value.

Therefore, even if the accelerator operation speed increases momentarily, if the accelerator operation speed remains low thereafter, the maximum value will gradually decrease,
On the contrary, if a large operation speed is frequently detected, the maximum value will be kept at a large value. Further, when an accelerator operation speed exceeding the maximum value is detected during the damping, the maximum operation speed is updated to the latest operation speed.

The attenuation amount in the attenuation processing unit 84 is set in the attenuation amount setting unit 85 based on the accelerator opening (accelerator operation amount). An accelerator opening signal from the accelerator opening sensor 51 is input to the attenuation amount setting unit 85, and a table in which the attenuation amount corresponding to the accelerator opening (accelerator operation amount) is stored in advance is stored. Then, the damping amount corresponding to the accelerator opening at that time is set.

With respect to the attenuation amount in the table, the attenuation amount becomes smaller as the accelerator opening becomes larger, and the attenuation is set to 0 at a predetermined accelerator opening or more. Therefore, when the accelerator operation is performed in a region where the accelerator opening is small, the maximum value is attenuated relatively quickly, but as the accelerator opening increases, the damping speed decreases, and the accelerator opening exceeds a predetermined value. When the accelerator operation is performed in the area of, the maximum value of the accelerator operation speed is held without being attenuated.

The maximum value of the accelerator operating speed that is attenuated as described above is output to the power performance requirement degree setting unit 86, where it is converted into a parameter indicating the degree of power performance requirement of the driver. Here, when the maximum value of the accelerator operation speed is large, it is determined that the degree to which the driver requests power performance is high.
Similarly, even when the maximum accelerator operation amount is large, it is determined that the degree to which the driver demands power performance is high.

Therefore, the larger the maximum value of the accelerator operating speed or the accelerator operating amount, the larger the number of steps allowed for the downshift in one shift operation. It should be noted that the method of obtaining the driver's driving intention (power performance demand degree) from the accelerator operation speed or the accelerator operation amount is not limited to the above, and the driver's intention to operate can be obtained by operating the dial or the like. May be allowed to be instructed.

On the other hand, in the case of a continuously variable transmission, step 22
The torque reduction amount is set as a correction coefficient of the basic gear ratio (basic torque ratio) corresponding to the steady state obtained by referring to the map from the operating conditions in the automatic mode. The setting is variably set according to the intention (see FIG. 8). That is, when the degree of power performance demand of the driver is high, the correction coefficient is set so that a value that is relatively close to the basic gear ratio retrieved from the map is the final basic gear ratio, and a relatively large downshift is performed. Allowed, but if the power performance requirement is low,
By setting a correction coefficient that brings the basic gear ratio retrieved from the map closer to the gear ratio in the manual mode, the downshift amount is sufficiently small and the torque down amount is relatively large.

In the actual gear change control based on the basic gear ratio, for example, a target gear ratio that follows the basic gear ratio at a predetermined gear speed is set, and feedback is performed so that the actual gear ratio matches the target gear ratio. Controlled. The correction coefficient of the basic gear ratio is set according to the driver's driving intention as described above, and is variable according to the output torque of the engine, the vehicle speed, the gear ratio (torque ratio), etc. at that time. It is preferable.

On the other hand, in the case of executing the smooth torque up control by the engine, the output torque down ratio of the engine simultaneously with the downshift accompanying the switching from the manual mode to the automatic mode (see FIG. 9) is performed in step 22. The torque reduction amount is determined. Also here, when the driver's power performance requirement is high, a relatively large increase in the output shaft torque is allowed, so the torque reduction amount may be small.
When the degree of demand for power performance is low, the torque reduction amount is increased so that a sudden increase in output shaft torque can be sufficiently suppressed (see FIG. 10).

The engine torque down rate is set according to the driver's driving intention as described above, and the engine output torque, vehicle speed, gear ratio (gear position or torque ratio), etc. at that time are set. Therefore, it is preferable to make it variable. The output torque of the engine can be forcibly reduced by, for example, reducing the intake air amount. For example, as shown in FIG. 2, an actuator 12 such as a motor for opening and closing the throttle valve 11 is provided and the actuator 12
A throttle controller 13 for controlling the opening / closing operation of the throttle valve 11 is provided. The throttle controller 13 controls the actuator 12 according to the torque reduction rate.

When the torque down amount is determined in the step 22, the execution time of the smooth torque up control is determined in the next step 23. Again, it is assumed that the execution time is determined according to the driver's power performance requirement, and when the power performance requirement is high, it is desired to return to the normal state relatively quickly. As shown in, the higher the power performance requirement degree, the shorter the execution time is preferably set.

For example, when the allowable number of downshift stages is set as the amount of torque reduction in the stepped transmission, as shown in FIG.
As shown in (A) or (B), during the execution time, the gear position is gradually downshifted from the gear position in the manual mode to the gear position required in the automatic mode according to the set allowable downshift stage number. In the example shown in FIG. 6A, the case where the fifth speed is selected in the manual mode, the first speed is the target gear position in the automatic mode, and the first allowable speed is set as the downshift speed In the execution time, the gears are downshifted one step from the fifth speed to the first speed.

The example shown in FIG. 6 (A) is a case where the driver's degree of power performance demand is low, and when the degree of power performance demand is high, as shown in FIG. 6 (B) within a shorter time. Downshifts will be made in the order of 5th → 3rd → 1st. Further, in the continuously variable transmission, when the correction coefficient of the basic speed ratio in the automatic mode is set as the torque reduction amount, the basic speed ratio corrected by the correction coefficient is step-changed at the same time when the mode is switched. rear,
Within the execution time, the basic gear ratio in the auto mode is gradually changed (see FIG. 17).

Further, in the case of smooth torque increase for forcibly reducing the output torque of the engine, as shown in FIG. 9, the throttle 11 is stepwise targeted based on the torque reduction ratio set in the step 22. After closing to the opening to reduce the engine output torque, the torque down amount is gradually reduced within the execution time (opening the throttle opening), and at the end of the execution time,
Make the amount of forcible torque reduction return to zero.

In step 24, initial values are set for executing the smooth torque up control. When gradually downshifting the stepped transmission, as shown in the flowchart of FIG. 12, the value obtained by subtracting the allowable number of downshift steps from the gear position selected in the manual mode (step 31 ), The target gear position in the first shift control is reached (step 32).

For example, when the gear position selected in the manual mode is the fifth speed and the allowable downshift number is two, the target gear position in the first shift after switching to the automatic mode is the third speed. Become. And then
Downshifting is executed stepwise based on the execution time and the allowable downshift stage number. Further, in the continuously variable transmission, as shown in the flowchart of FIG. 13, the basic gear ratio in the auto mode is obtained from the map, and the gear ratio obtained by correcting this basic gear ratio with the correction coefficient is used as the initial value for the automatic mode return. (Step 41).

Further, when reducing the engine output torque, as shown in the flowchart of FIG. 14, a target torque is obtained from the torque reduction ratio and the current output torque (step 51), and the target torque is set to the throttle valve. It is converted to the target opening of 11 (step 52) and the initial opening of the throttle valve 11 is determined (step 53). When the initial setting is completed as described above, the process will proceed from step 21 to step 25 from the next time to gradually downshift from the initial state within the execution time (see FIGS. 6A and 6B).
Alternatively, the torque up control is executed by gradually reducing the down amount of the output torque of the engine and gradually returning the output torque (see FIG. 9).

[0062]

As described above, according to the first aspect of the present invention, when the manual mode is switched to the automatic mode, it is possible to prevent the output shaft torque from rapidly increasing due to the sudden torque reduction. There is an effect that the stability of the vehicle can be reliably maintained.

According to the second aspect of the invention, there is an effect that it is possible to surely determine whether or not a downshift of a predetermined amount or more will be performed when the manual mode is switched to the automatic mode. According to the third aspect of the present invention, when the gearshift or the normal mode shift causes a downshift of a predetermined value or more, it is determined according to the auto mode from the gear position or the torque ratio in the manual mode before the shift. By gradually changing the gear position or torque ratio to a certain value, it is possible to suppress an increase in the output shaft torque due to the downshift.

According to the fourth aspect of the invention, there is an effect that an increase in the output shaft torque when downshifting in accordance with the mode switching can be relatively suppressed by reducing the engine output torque. According to the invention of claim 5, the engine output torque is reduced at the same time as the mode switching, and then the output torque is gradually recovered.
There is an effect that the increase of the output shaft torque can be effectively suppressed.

According to the sixth aspect of the present invention, there is an effect that it is possible to sufficiently suppress the sudden increase in the output shaft torque due to the downshift caused by the mode switching, while ensuring the drivability that meets the driver's demand. According to the invention described in claim 7, it is possible to obtain a variation characteristic of the output shaft torque that meets the driver's request while suppressing a sudden increase in the output shaft torque due to the downshift accompanying the mode switching.

According to the eighth aspect of the invention, there is an effect that the driver's driving intention can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the invention according to claim 1;

FIG. 2 is a system configuration diagram of the automatic transmission according to the embodiment.

FIG. 3 is a flowchart showing torque control associated with mode switching.

FIG. 4 is a diagram showing an example of a shift schedule in a stepped transmission.

FIG. 5 is a flowchart showing details of torque control at the time of mode switching.

FIG. 6 is a time chart showing a state of shift control at the time of mode switching in a stepped transmission, where (A) is a case where a driver's power performance demand is low, and (B) is a driver's power performance demand. Chart when the value is high.

FIG. 7 is a diagram showing a setting characteristic of an allowable downshift stage number in a stepped transmission.

FIG. 8 is a diagram showing a setting characteristic of an initial downshift correction coefficient in a continuously variable transmission.

FIG. 9 is a time chart showing how the output torque of the engine is controlled during mode switching.

FIG. 10 is a diagram showing a setting characteristic of a down ratio of an output torque of an engine when switching modes.

FIG. 11 is a diagram showing a setting characteristic of time for torque-up control.

FIG. 12 is a flowchart showing a state of initial setting of downshift control in the stepped transmission.

FIG. 13 is a flowchart showing a state of initial setting of downshift control in the continuously variable transmission.

FIG. 14 is a flowchart showing a state of initial setting of engine output torque down control.

FIG. 15 is a time chart showing changes in output shaft torque due to mode switching.

FIG. 16 is a block diagram showing a configuration for detecting the degree of power performance requirement of a driver.

FIG. 17 is a time chart showing a state of torque down control in the continuously variable transmission.

[Explanation of symbols]

 1 Engine 2 Transmission 3 Hydraulic Circuit 4 A / T Control Unit 5 ENG Control Unit 6 Select Lever 11 Throttle Valve 12 Actuator 13 Throttle Controller

Claims (8)

[Claims] 1. A manual mode in which a gear position or a torque ratio in a transmission can be arbitrarily selected, an automatic mode in which a gear position or a torque ratio in a transmission is determined according to a preset schedule, and the manual mode and the automatic mode. In a control device for an automatic transmission equipped with a mode selection means for arbitrarily selecting one of the above, a downshift of a predetermined value or more is performed when the manual mode is switched to the automatic mode by the mode selection means. An automatic transmission control device comprising an output shaft torque change suppressing means for forcibly suppressing an increase change in the output shaft torque of the transmission due to a downshift under the above conditions. 2. A gear position or torque ratio to be determined according to the automatic mode when the output shaft torque change suppressing means is switched from the manual mode to the automatic mode by the mode selecting means, and a manual before switching. The control device for an automatic transmission according to claim 1, wherein it is determined whether or not a condition for performing a downshift of a predetermined value or more is determined based on a gear position or a torque ratio in the mode. 3. The output shaft torque change suppressing means gradually changes from a gear position or a torque ratio in a manual mode before switching to a gear position or a torque ratio determined according to the automatic mode, thereby changing the output shaft torque. 3. An increase change in torque is suppressed, as claimed in claim 1 or 2.
3. The control device for an automatic transmission according to claim 1. 4. The output shaft torque change suppressing means forcibly controls the output torque of the engine in a direction of suppressing an increase change in the output shaft torque due to a downshift. A control device for the automatic transmission described. 5. The output shaft torque change suppressing means reduces the output torque of the engine by a predetermined value at the same time as the downshift accompanying the mode switching, and then gradually reduces the torque down amount of the engine to reduce the output shaft torque. The control device for an automatic transmission according to claim 4, wherein the control device gradually increases. 6. The output shaft torque change suppressing means changes an amount of suppressing an increase change in the output shaft torque according to a parameter indicating a driving intention of a driver. The control device for the automatic transmission according to any one of claims. 7. The output shaft torque change suppressing means gradually increases and changes the output shaft torque at a changing speed according to a parameter indicating a driving intention of the driver. A control device for an automatic transmission according to one. 8. The automatic transmission according to claim 6, wherein the parameter indicating the driving intention of the driver is set based on at least one of an accelerator operation speed and an accelerator operation amount. Control device.