JP3389709B2 - Transmission control device for continuously variable transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a continuously variable transmission aiming at improving the drivability of a vehicle equipped with the continuously variable transmission during acceleration such that the accelerator pedal is greatly depressed.

[0002]

2. Description of the Related Art A continuously variable transmission such as a toroidal continuously variable transmission or a V-belt type continuously variable transmission usually has an engine throttle opening and a vehicle speed that represent a current operating state, based on a predetermined shift pattern. According to the gear shift control target value (normally, it is the target value of the transmission input speed such as the engine speed and the transmission input speed, but there may be a gear ratio equivalent to this).
Is calculated, and shift control is performed so that this shift control target value is achieved.

Here, the shift pattern of the continuously variable transmission is as shown in FIG. 13, for example, and the transmission input speed target value N is set by the throttle opening TVO and the vehicle speed VSP within the control limit of the continuously variable transmission. _i ^* (the target speed ratio corresponding to the vehicle speed VSP and the target input speed N _i ^* is known)
Is predetermined.

By the way, consider a case where the driving condition is changed from, for example, x point to y point in the same figure as a result of accelerating the engine by kicking down the accelerator pedal at a certain vehicle speed. Since the target input rotation speed N _i ^* is a high rotation speed corresponding to the y point, the continuously variable transmission first performs a downshift shift to increase the input rotation speed to this high rotation speed, and thereafter. For the first time, the vehicle speed VSP increases as indicated by arrow α. Therefore,
During the initial period, the kickdown described above only raises the engine speed, but the vehicle is not accelerated, which causes discomfort regarding the acceleration performance of the vehicle.

As a shift control technique for a continuously variable transmission relating to this point, there is a conventional shift control technique described in, for example, Japanese Patent Laid-Open No. 59-208253. This speed change control technique is such that when the vehicle is accelerated from a low speed or low load state of the engine, the speed ratio is fixed to the speed ratio before acceleration during a predetermined time period at the beginning of acceleration. According to this shift control technology, the increase in engine rotation due to the acceleration operation is directed to the improvement of the acceleration performance during the above predetermined time, and the absolute driving force is sacrificed because the control deviates from the planned shift pattern. However, since the acceleration performance is improved, it is possible to eliminate the discomfort regarding the acceleration performance.

[0006]

However, according to such a conventional shift control device, the gear ratio is kept unchanged during a predetermined time period at the beginning of acceleration. Therefore, a predetermined shift pattern during the predetermined time period is required. , The absolute sacrifice amount of the driving force directed to the improvement of the acceleration performance is the same regardless of the engine operating load (difference in road surface slope, difference in loading amount, etc.). Therefore, the absolute drive force sacrifice amount that is allotted to the improvement of acceleration performance during high load operation is too large, and the absolute drive force is not insufficient during high load operation, or a large drive force is not required. During low-load operation, there is a concern that the absolute driving force sacrificed to improve acceleration performance is too small and a sufficient acceleration performance improvement effect cannot be obtained during low-load operation.

In order to solve this problem, a running condition that is a factor that changes the engine operating load is detected one by one, and the gear ratio that is kept unchanged during a predetermined time in the initial stage of acceleration is made different according to the detection result. It is possible to add such control, but in this case, because the means for detecting the traveling condition is separately required and the control becomes complicated, the cost of the shift control device is increased, and it is practical. Not.

According to the present invention, without causing such an increase in cost, a gear shift in which the absolute sacrifice amount of the driving force, which is directed to the effect of improving the acceleration performance, changes in a logical manner in accordance with the driving load. The purpose is to propose a device that can realize control.

[0009]

To this end, a transmission control device for a continuously variable transmission according to a first aspect of the present invention, as shown in the concept of FIG. Acceleration operation that detects an acceleration operation above a certain level in a vehicle in which the engine output is transmitted to the wheels via a continuously variable transmission that is gear-shift-controlled by a gear-shift actuator to achieve a corresponding gear-shift control target value. When the acceleration operation is detected, the transmission input side rotation speed is higher than the shift control target value before the acceleration operation, but the transmission input side rotation is higher than the shift control target value corresponding to the acceleration operation. An acceleration shift control target value storage unit that stores a planned shift control target value during acceleration, and a travel distance measurement unit that measures a vehicle travel distance from the time when the acceleration operation is detected,
After the acceleration operation is detected, the speed change control target value stored in the acceleration speed change control target value storage means is used as a reference to gradually change the speed according to an increase in the travel distance after acceleration measured by the travel distance measuring means. And a shift control target value correcting means for instructing the shift actuator to replace the corrected shift control target value that changes so as to increase the machine input side rotational speed with the shift control target value determined based on the shift pattern. It is characterized by doing.

Further, in the shift control device for a continuously variable transmission according to the second aspect of the present invention, the corrected shift control target value from the shift control target value correction means is equal to the shift control target value determined based on the shift pattern. When the temperature has risen, the correction of the shift control target value by the shift control target value correcting means is terminated, and the shift control target value correction ending means for instructing the shift control target value determined based on the shift pattern to the shift actuator It is characterized by the addition of.

Further, the speed change control device for a continuously variable transmission according to the third aspect of the present invention further comprises a vehicle speed detecting means for detecting a vehicle speed, and the speed change control target value correcting means is responsive to a signal from the means to change the speed control target value correcting means. A modified shift control target value that changes so as to increase the transmission input side rotational speed at a higher rate at a higher vehicle speed in accordance with an increase in the traveling distance afterward is configured to be commanded to the shift actuator. is there.

[0012]

In the first aspect of the invention, the continuously variable transmission determines the gear shift control target value according to the driving condition based on the predetermined gear shift pattern, and the gear shift actuator controls the gear shift so that this is achieved. The engine output is transmitted to the wheels via the transmission to drive the vehicle.

Here, the acceleration operation detecting means detects an acceleration operation above a certain level of the engine, and the acceleration-time shift control target value storage means detects the acceleration operation, and the transmission control ratio is higher than the shift control target value before the acceleration operation. Although the input side rotation speed is large, the gear shift control target value for acceleration is planned to be smaller than the shift control target value corresponding to the acceleration operation, and the acceleration shift control target value is stored. The distance traveled by the vehicle after the acceleration operation is detected is measured. After the acceleration operation is detected, the shift control target value correction means uses the acceleration shift control target value stored in the acceleration shift control target value storage means as a reference and travels after acceleration measured by the travel distance measuring means. As a modified shift control target value, a shift control target value that changes so as to gradually increase the transmission input side rotational speed in accordance with an increase in distance is used as a modified shift control target value instead of the shift control target value determined based on the shift pattern. Order.

Therefore, according to the first aspect of the present invention, during the above-described acceleration operation, the gear shift control target value is not suddenly changed to the gear shift control target value corresponding to the acceleration operation, and the gear shift control target value is less than the gear shift control target value. Also achieves a modified shift control target value that gradually changes from the planned shift control target value during acceleration, which gradually increases the transmission input speed, as the above travel distance increases. The gear shift is performed as described above. Therefore, at the beginning of the acceleration operation described above, it is possible to eliminate a feeling of discomfort regarding the acceleration performance that the engine speed only increases and the vehicle is not accelerated.

Since the corrected gear shift control target value is set to the gear shift control target value which gradually changes so as to increase the transmission input side rotational speed in accordance with the increase in the traveling distance, the following operational effects can be obtained. In other words, considering the vehicle speed when traveling the same distance, the vehicle speed is naturally lower when the load is high than when the load is low. When the vehicle is in a high load state, the deviation from the planned shift pattern, that is, the absolute amount of the driving force sacrificed to improve the acceleration performance, is smaller when the vehicle is under a heavy load than when the vehicle is under a low load. Therefore, depending on the engine operating load (difference in road slope, difference in loading capacity, etc.),
The absolute amount of driving force that is used to improve acceleration performance is small during high-load operation, and there is no shortage of absolute driving force during high-load operation. Conversely, large driving force is not required. During low load operation, the absolute amount of driving force that is directed to improving acceleration performance is increased, and during low load operation, sufficient acceleration performance improving effect is obtained. It is possible to realize the shift control such that the sacrificed amount of the driving force to be applied becomes reasonable.

Moreover, since the shift control according to the engine operating load as described above can be performed without detecting any running condition that influences the engine operating load, it is not necessary to add a running condition detecting means. For the reason that the control does not become complicated, the above-mentioned effects can be achieved at low cost.

In the second aspect of the invention, when the corrected shift control target value from the shift control target value correcting means rises to the same value as the shift control target value determined based on the shift pattern, the shift control target value is corrected. The termination means terminates the modification of the gear shift control target value by the gear shift control target value modification means and issues a command to the gear shift actuator for the gear shift control target value determined based on the gear shift pattern. In this case, the above correction of the shift control target value is accurately finished,
It is possible to prevent the shift control from being shifted to an undesired side from the shift pattern.

In the third aspect of the invention, the gear shift control target value correcting means responds to the vehicle speed detected by the vehicle speed detecting means to increase the transmission input side rotational speed as the vehicle speed increases in accordance with the increase in the traveling distance after the acceleration. The modified shift control target value that changes so as to increase at a rate is commanded to the shift actuator.
In this case, the higher the vehicle speed is, the shorter the distance is, and the shift control target value for returning the target shift control value to the one corresponding to the shift pattern is performed. Can be realized.

[0019]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 illustrates a shift control device for a continuously variable transmission according to the present invention, where 1 is an engine as an engine and 2 is an engine.
Indicates a continuously variable transmission. Here, the continuously variable transmission 2 is as described in, for example, Japanese Patent Application Laid-Open No. 2-292562 previously proposed by the applicant of the present application, and a shift control valve (not shown) is stroked by a shift motor 3 as a shift actuator. By doing so, the shift control is performed so as to achieve the shift control target value. Here, although the shift control target value will be described later in detail, the target input rotation speed of the transmission is basically set, and basically, as shown by a solid line in FIG.
And the vehicle speed VSP is given as a planned shift pattern.

The transmission motor 3 is controlled by the transmission controller 4, and therefore the transmission controller 4 detects the signal from the throttle opening sensor 5 for detecting the throttle opening TVO of the engine 1, the vehicle speed VSP. The signal from the vehicle speed sensor 6 corresponding to the vehicle speed detecting means and the signal from the distance sensor 7 for detecting the traveling distance D of the vehicle are input. Regarding the travel distance D, the vehicle speed sensor 6
It is also possible to detect by counting up the pulse signal from, and in this case, the distance sensor 7 can be omitted.

Based on these input information, the controller 4 executes the control program of FIG. 3 to perform the shift control of the continuously variable transmission 2 via the motor 3 as follows. First, at step 11, throttle opening TVO, vehicle speed VSP
And it reads the travel distance D, the next step 12, the target input rotation speed corresponding to the throttle opening TVO and vehicle speed VSP based on a shift pattern shown by the solid line in FIG. 13 N _i
Search for ^* .

In step 13, it is checked whether or not the flag FLAG is 1 so as to indicate that the shift control for kickdown is being performed. If the shift control for kickdown is not yet performed, it corresponds to an acceleration operation detecting means. In step 14, it is checked whether or not there is a kick down operation (acceleration operation). For the determination of this kickdown operation (acceleration operation), the determination methods of FIGS. 4 to 7 can be considered.

The determination method of FIG. 4 is based on the throttle opening TVO.
Is set in the control memory TVO1, and when the control memory TVO1 is equal to or more than a predetermined value, it is determined that a kick down operation has been performed. When the control memory TVO1 is less than the predetermined value, it is determined that the kick down operation is not performed. It is a thing.

The determination method of FIG. 5 is based on the control memory TVO1.
Is stored in the control memory OLDTVO, and the throttle opening TVO is stored in the control memory TVO1.
Throttle opening change amount dTVO during the calculation cycle
Is calculated by dTVO = TVO1−OLDTVO, when the throttle opening change amount dTVO is equal to or more than a predetermined value, it is determined that there is a kick down operation, and when the throttle opening change amount dTVO is less than the predetermined value, the kick is performed. It is determined that it is not the down operation.

The determination method of FIG. 6 is such that the target input speed N _i ^*
Control memory T. Stored in the N _i, the control memory T. When N _i is equal to or greater than a predetermined value, it is determined that a kick down operation has been performed, and the control memory T.N. When N _i is less than the predetermined value, it is determined that the kick-down operation is not performed.

The determination method shown in FIG. N_i
Control memory OLDT. N_iMemorized in the target input rotation
Number N_i ^*Control memory T. N_iRemember from these
Target input speed change amount dN in one calculation cycle_i
^*To dN_i ^*= T. N_i-OLDT. N_iCalculated by
After this, this target input speed change amount dN_i ^*Is more than the specified value
If it is, it is determined that there was a kickdown operation, and the target
Force rotation speed change amount dN_i ^*Is less than the specified value, the kick
It is determined that it is not the down operation.

If it is determined from the above determination that the operation is not a kickdown operation, step 1 in step 23 of FIG.
The target input rotation speed N _i ^* in 2 is commanded to the motor 3 of FIG. 2 as it is, and the continuously variable transmission 2 is shift-controlled so that this target input rotation speed N _i ^* is achieved.

When it is determined in step 14 that the kick down operation is performed, in step 15, the running distance read value D is executed by executing the control program of FIG.
_Is stored as the traveling distance D _kd during the kickdown operation.
Then, in step 16 corresponding to the acceleration shift control target value storage means, the control program of FIG. 9 is executed to execute the vehicle speed based on the acceleration target input rotation speed characteristic for kickdown shown by the broken line in FIG. The target input speed N _ikd ^* during acceleration for kickdown corresponding to VSP is searched by the table lookup method. Here, the target input speed (N _ikd ^* ) characteristic during acceleration is determined from the target input speed (N _i ^* ) characteristic corresponding to the kick-down operation so that the above-mentioned acceleration performance improving effect is achieved during kick-down. Also set to a low speed. When the kick down operation from the x point to the y point is performed as described above, the acceleration target input rotation speed _Nikd ^* is the rotation speed at the z point.

Next, at step 17, the flag FLAG is set to 1 so as to indicate that the shift control for kickdown is being performed. As a result, step 13 skips steps 14 to 17 and the control proceeds to step 18 thereafter.
˜17 are executed only once when the kick down operation is performed.

Step 18 corresponds to the shift control target value correcting means. Here, the control program of FIG. 10 is executed to calculate the corrected target input rotational speed N _i ^** . In this calculation, as shown in FIG. 10, first, the kick-down travel distance D _kd stored in step 15 is subtracted from the current travel distance read value D (this processing corresponds to travel distance measuring means). The traveling distance a from when the kick down operation is performed is calculated. Next, the constant C corresponding to the vehicle speed VSP is searched from the map of FIG. Here, the constant C is increased in a quadratic curve as the vehicle speed VSP increases for the purpose described later. Then, the corrected target input rotation speed N _i
^** is obtained by the calculation of N _i ^** = C · a + N _ikd ^* .

In step 19 of FIG. 3, the target input speed N _i ^* in step 12 and the corrected target input speed N _i ^** are compared in magnitude. Corrected target input rotation speed N _i
Until ^** increases to the same value as the target input speed N _i ^* , in step 20, the corrected target input speed N _i ^** is replaced with the target input speed N _i ^* as the shift control target value, By instructing this to the motor 3 in step 23, the shift control for kickdown such that the corrected target input rotation speed N _i ^** is achieved is executed.

After it is determined in step 19 that the corrected target input speed N _i ^** exceeds the target input speed N _i ^* , the shift control target value is set to the corrected target input speed N _{i in} step 21. ^The target input speed N _i ^* is returned from ^**, and the flag FLAG is reset to 0 in step 22 so as to indicate that the shift control for kickdown has been completed. The shift control is performed based on the normal shift pattern such that the number N _i ^* is achieved.

According to the above operation, as shown in FIG.
When there is a kickdown due to the throttle opening operation
Explaining about it, reading the mileage during kickdown
Value D _kdEngine speed increases as the vehicle travels from
Is indicated by the solid line, compared to the uncontrolled case indicated by the broken line.
The shift control is suppressed so that this
The amount by which gin rotation is suppressed causes an absolute decrease in driving force.
Of the kick-down control
If there is a problem, the engine speed will only increase and the vehicle will
Eliminate discomfort related to acceleration performance, such as not being accelerated
can do.

Moreover, considering the vehicle speed when traveling the same distance from the kickdown operation, the vehicle speed is naturally lower than the low load when the vehicle is under a high load.
As indicated by β in 3, the gear shift returns to match the planned kick-down shift pattern (indicated by α) at a lower vehicle speed than under low load (indicated by γ), and during high load it is lower than during low load. Also, the deviation from the planned kickdown shift pattern α, that is, the amount of absolute driving force sacrificed for improvement of acceleration performance is small. Therefore, depending on the operating load (differences in road surface slope, loading capacity, etc.), the absolute amount of driving force sacrificed to improve acceleration performance during high load operation is small, and the In the low load operation that does not require a large drive force, on the contrary, the absolute drive force sacrifice for improving the acceleration performance increases and the low load operation It is possible to realize the shift control such that the sacrifice amount of the driving force that is directed to the acceleration performance improving effect is reasonable, such as that the sufficient acceleration performance improving effect is obtained.

In addition, as described above, only the control according to the traveling distance from the kickdown operation is performed, and accordingly, the traveling load is controlled according to the driving load as described above without detecting any traveling condition that influences the driving load. A rational shift control can be realized, and the above-described effects can be achieved without incurring any cost increase.

It should be noted, modify the constant C used when calculating the target input rotational speed N _i ^**, since to increase with increasing vehicle speed VSP as shown in FIG. 11, the corrected target input revolution speed N _i ^** High The vehicle speed increases to the same value as the target input speed N _i ^* corresponding to the planned kick-down shift pattern in a shorter distance. As a result, as is clear from the change in engine speed of FIG. 12, the higher the vehicle speed VSP, the closer to the gear shift characteristics when the control of the present invention is not performed, which is indicated by the broken line, and suitable for the high vehicle speed with a high load. It is possible to realize gear shift control with an emphasis on driving force.

[0037]

As described above, the shift control device for a continuously variable transmission according to the first aspect of the present invention, as described in claim 1, when the engine is accelerated more than a certain level, a normal shift control target corresponding to the acceleration operation is provided. Corrected gear shift that gradually increases the transmission input-side rotation speed as the mileage after acceleration increases, with the transmission input-side rotation speed becoming smaller than the value Since the control target value is configured to be used in place of the normal shift control target value, the shift control target value is suddenly changed to the shift control target value corresponding to the acceleration operation during the acceleration operation. Therefore, the transmission input-side rotational speed is gradually changed from the gear-shift input-side rotational speed that is smaller than the transmission control-target value to gradually increase the transmission input-side rotational speed according to the increase in the travel distance. Modified shift It becomes possible to perform a shift, such as to achieve the control target value. Therefore, at the beginning of the above acceleration operation, the engine speed only increases, but the vehicle is not accelerated.
It is possible to eliminate discomfort regarding acceleration performance.

Since the corrected gear shift control target value is set to the gear shift control target value that changes so as to gradually increase the transmission input side rotation speed in accordance with the increase in the traveling distance, the following operational effects can also be obtained. In other words, considering the vehicle speed when traveling the same distance, the vehicle speed is naturally lower when the load is high than when the load is low. When the vehicle is in a high load state, the deviation from the planned shift pattern, that is, the absolute amount of the driving force sacrificed to improve the acceleration performance, is smaller when the vehicle is under a heavy load than when the vehicle is under a low load. Therefore, depending on the engine operating load (difference in road slope, difference in loading capacity, etc.),
The absolute amount of driving force that is used to improve acceleration performance is small during high-load operation, and there is no shortage of absolute driving force during high-load operation. Conversely, large driving force is not required. During low load operation, the absolute amount of driving force that is directed to improving acceleration performance is increased, and during low load operation, sufficient acceleration performance improving effect is obtained. It is possible to realize the shift control such that the sacrificed amount of the driving force to be applied becomes reasonable.

Moreover, since it is possible to perform the shift control according to the engine operating load as described above without detecting any running condition that influences the engine operating load, it is not necessary to add a running condition detecting means. For the reason that the control does not become complicated, the above-mentioned effects can be achieved at low cost.

According to a second aspect of the present invention, in the shift control device for a continuously variable transmission, the corrected shift control target value rises to the same value as the shift control target value determined based on the shift pattern. By the way, since the modification of the shift control target value is finished and the shift control target value determined based on the shift pattern is instructed to the shift actuator, the modification of the shift control target value is accurately finished. Therefore, it is possible to prevent the shift control from being shifted to an undesired side from the shift pattern.

Further, in the transmission control device for a continuously variable transmission according to the third aspect of the present invention, as described in claim 3, the corrected shift control target value increases the rotational speed of the transmission input side in response to an increase in the traveling distance after acceleration. Since the vehicle speed is changed so as to increase at a higher rate, the higher the vehicle speed, the shorter the distance will be to perform the shift control that emphasizes the driving force and returns the shift control target value to the one that corresponds to the shift pattern. It is possible to realize gear shift control suitable for high vehicle speed driving, which is often the case.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a shift control device for a continuously variable transmission according to the present invention.

FIG. 2 is a control system diagram of a continuously variable transmission showing an embodiment of a shift control device of the present invention.

FIG. 3 is a flowchart showing a main routine of a shift control program executed by a transmission controller in the example.

FIG. 4 is a flowchart showing a subroutine relating to a kickdown determination program in the main routine.

FIG. 5 is a flowchart showing another example of the kickdown determination program.

FIG. 6 is a flowchart showing yet another example relating to the kickdown determination program.

FIG. 7 is a flowchart showing still another example of the kickdown determination program.

FIG. 8 is a flowchart showing a process of storing a running distance during kickdown in the main routine of FIG.

9 is a flowchart showing a search process of a target input rotation speed during acceleration in the main routine of FIG.

10 is a flowchart showing a process of calculating a corrected target input rotation speed in the main routine of FIG.

FIG. 11 is a change characteristic diagram of constants used in the process of calculating the corrected target input rotation speed.

FIG. 12 is a diagram when a kickdown operation is performed.
3 is a time chart of the shift control operation of FIG.

FIG. 13 is a diagram showing the same shift control operation on a shift pattern of a continuously variable transmission.

[Explanation of symbols]

1 engine 2 continuously variable transmission 3 Speed change motor (speed change actuator) 4 Transmission controller 5 Throttle opening sensor 6 Vehicle speed sensor (vehicle speed detection means) 7 Distance sensor

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/00-63/38 F16H 9 / 00

Claims (3)

(57) [Claims] 1. A determination is made based on a planned shift pattern,
Detects engine acceleration above a certain level in a vehicle that transmits engine output to wheels via a continuously variable transmission that is gear-shift-controlled by a gear-shift actuator so that a gear-shift control target value according to operating conditions is achieved. And a transmission input side rotational speed that is larger than the shift control target value before the acceleration operation when the acceleration operation is detected, but the transmission is higher than the shift control target value corresponding to the acceleration operation. Acceleration shift control target value storage means for storing a planned acceleration shift control target value at which the input side rotational speed is small; travel distance measuring means for measuring a vehicle travel distance from the acceleration operation detection; After the operation is detected, the traveling distance after acceleration measured by the traveling distance measuring means with reference to the acceleration shift control target value stored in the acceleration shift control target value storage means. The modified shift control target value, which gradually changes to increase the transmission input side rotational speed in response to an increase in the separation, is replaced with the shift control target value determined based on the shift pattern, and a shift commanded to the shift actuator is given. A shift control device for a continuously variable transmission, comprising: a control target value correction means. 2. The shift control target value according to claim 1, when the corrected shift control target value from the shift control target value correction means rises to the same value as the shift control target value determined based on the shift pattern. The present invention is characterized in that a shift control target value correction ending means for ending the correction of the shift control target value by the correction means and instructing the shift actuator of the shift control target value determined based on the shift pattern is added. Shift control device for continuously variable transmission. 3. A vehicle speed detecting means for detecting a vehicle speed according to claim 1 or 2, wherein said shift control target value correcting means increases the traveling distance after acceleration in response to a signal from said means. In accordance with the above, the shift control device for a continuously variable transmission is configured to instruct the shift actuator of a corrected shift control target value that changes so as to increase the input speed of the transmission at a higher rate as the vehicle speed increases. .