JPH05332426A - Speed change control device of continuously variable transmission - Google Patents

Abstract

PURPOSE:To keep occupants from feeling embarrassed without deteriorating acceleration responsiveness and to decrease engine noise. CONSTITUTION:A speed change control device of a continuously variable transmission includes a reference value setting means 17 for setting a control reference value according to a preset control map and a speed change drive portion 12 which varies the change gear ratio of the continuously variable transmission according to a desired speed change value corresponding to the control reference value. The control device is further provided with an identification means 19 for determining whether or not sudden acceleration is required according to the amount of control of an accelerator pedal and a sudden acceleration control means 20 which varies the gear change ratio stepwise when the identification means 19 makes sure that sudden acceleration is required, so that vehicle speed is increased as engine speed is gradually increased and suddenly decreased.

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 which controls a gear ratio of a continuously variable transmission mounted on a vehicle in accordance with an operating condition.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 55-65755, a gear shift target value of the continuously variable transmission is read out based on a preset control map, and the gear shift target value is read according to the gear shift target value. In the V-belt type continuously variable transmission configured to control the gear ratio of the continuously variable transmission, by changing the control state of the gear ratio according to the operation state of the accelerator pedal, that is, the opening degree of the throttle valve, Shift control suitable for the driving state of a vehicle is executed.

As shown in FIG. 7, the control map normally comprises a graph in which the control reference value of the engine speed EPS with the vehicle speed V as a parameter is variously set according to the throttle opening TVO. The gear shift target value is set based on the engine speed EPS and the vehicle speed V read from. When the throttle opening TVO is large, the gear shift target value is set so that the engine speed EPS is rapidly increased, whereby a large driving force is obtained. Further, when the throttle opening TVO is small, the shift target value is set so that the engine speed EPS does not suddenly increase, thereby improving the fuel consumption rate.

[0004]

In the above-mentioned conventional continuously variable transmission, when the driver requests a sudden acceleration with the throttle opening fully opened, the gear ratio is changed as shown by the solid line α in FIG. Is set to the maximum value, the engine speed EPS is increased to the maximum area in the low vehicle speed V range, and then the gear ratio is gradually reduced to accelerate the engine speed EPS. Does not change and only the vehicle speed V increases, which gives the occupant a feeling of discomfort. Further, since the engine is maintained in the high rotation speed region for a long time, there is a problem that a large engine noise is generated.

Therefore, as shown by a broken line β in FIG. 8, when the engine speed EPS has risen to some extent, the gear ratio is gradually reduced to accelerate the engine to increase the engine speed EPS. While increasing the vehicle speed V, the vehicle speed V is being increased. However, in the case of such a configuration, there is a problem that the driving torque applied to the wheels is reduced by the range indicated by the diagonal lines and the acceleration response is deteriorated.

The present invention has been made in order to solve the above-mentioned problems, and does not reduce the acceleration response,
An object of the present invention is to provide a shift control device for a continuously variable transmission that can eliminate the discomfort given to an occupant and reduce engine noise.

[0007]

The invention according to claim 1 is
A reference value setting unit that sets a control reference value based on a preset control map, and a shift drive unit that changes the gear ratio of the continuously variable transmission based on a shift target value corresponding to the control reference value are provided. A shift control device for a continuously variable transmission, comprising: a determining unit that determines whether or not a rapid acceleration is required according to an operation amount of an accelerator pedal; and a determining unit that determines that the rapid acceleration is required. When it is confirmed, a sudden acceleration control means for gradually changing the speed change ratio so as to increase the vehicle speed while repeating the gradual increase and the sudden decrease of the engine speed is provided.

According to a second aspect of the present invention, the continuously variable transmission has a pair of discs installed opposite to each other and a roller arranged between the both discs, and the rollers abut against the disc. It is configured by a toroidal type transmission that changes the gear ratio by adjusting the position.

[0009]

According to the invention described in claim 1, when it is confirmed that the driver depresses the accelerator pedal to a large degree to request the sudden acceleration, the engine speed rapidly increases and the acceleration response is increased. As a result, the engine speed is reduced by shifting gears in the upshifting direction thereafter, and the vehicle speed is increased while the engine speed is increased again.

According to the second aspect of the present invention, by adopting the above configuration in the shift control device of the continuously variable transmission including the toroidal type transmission having excellent shift response, the engine speed is gradually increased. Then, the gear ratio control in which the sudden decrease is repeated is quickly and appropriately executed.

[0011]

1 is a block diagram of a continuously variable transmission 1 according to an embodiment of the present invention.
2 shows a drive system of a vehicle equipped with the shift control device of FIG.
The continuously variable transmission 1 is an output shaft that transmits a driving force to an input shaft 5 that is connected to a crank shaft 3 of an engine 2 via an electromagnetic clutch 4 and a final reduction gear 7 that is connected to drive wheels 6 of a vehicle. 8, a drive pulley 9 and a driven pulley 10 attached to the input shaft 5 and the output shaft 8, and a V-belt 11 wound around these pulleys 9 and 10. It should be noted that instead of the electromagnetic clutch 4, a fluid coupling, a torque converter, a centrifugal clutch or the like may be used.

Then, by changing the effective diameters of the pulleys 9 and 10 by a gear shift drive unit 12 having a hydraulically driven gear shift control valve, a gear ratio consisting of a rotational speed ratio of the input shaft 5 and the output shaft 8 can be obtained. Is being changed steplessly. That is, the shift drive unit 12 is configured to drive the drive pulley 9 according to the control signal output from the shift control device.
By adjusting the line hydraulic pressure or the flow rate supplied to the driven pulley 10, the effective diameters of the pulleys 9 and 10 are adjusted so that the gear ratio of the continuously variable transmission 1 matches the target value. ..

The shift control device is based on the detection signal of the engine sensor 13 for detecting the engine speed, the detection signal of the throttle sensor 14 for detecting the throttle opening, and the detection signal of the vehicle speed sensor 15 for detecting the vehicle speed. The control unit 16 reads out a target gear ratio corresponding to the running state of the vehicle. Then, the actual gear ratio of the continuously variable transmission 1 is made to match the target gear ratio by performing feedback control according to the engine speed ESP based on the control signal output from the control unit 16 to the gear shift drive unit 12. Is configured.

As shown in FIG. 2, the control section 16 transmits the driving force to the input shaft 5 of the continuously variable transmission 1 based on a preset normal control map (see FIG. 7). A reference value setting means 17 for setting a control reference value consisting of two rotation speeds, that is, a reference value of the engine speed ESP;
A control signal corresponding to the control reference value is sent to the shift drive unit 1 as described above.
2 and the shift control means 18 which outputs to the 2nd. In the normal control state, the control signal corresponding to the control reference value is output, so that the throttle opening TVO
Is configured to obtain a driving force corresponding to.

Further, the control section 16 determines whether or not the accelerator pedal is in a state of requesting rapid acceleration above a preset kickdown position in accordance with a detection signal from the throttle sensor 14 or not. And this determination means 1
When it is confirmed in 9 that the sudden acceleration is required, the sudden acceleration control means 20 is provided which changes the gear ratio of the continuously variable transmission 1 stepwise. Then, in the sudden acceleration request state, as shown in FIG. 3, the engine speed ESP is gradually increased and rapidly decreased, and the vehicle speed V is increased.
The control reference value is set on the basis of the graph set so as to increase, and the control signal corresponding to this is output.

That is, in the first region where the vehicle speed V is the smallest, the control reference value is set so that the engine speed ESP rapidly increases from 0 to the maximum value as shown by the line a in FIG. In the second region where the vehicle speed V is higher than the first region, as shown by the line b, the engine speed ESP is set to gradually increase from the first set value A set to a value lower than the maximum value to the maximum value. Has been done.

As a result, the vehicle speed V changes from the first range to the second range.
At the time of shifting to the region, the engine speed ESP is suddenly reduced from the maximum value to the first set value A. Further, in the third region and thereafter where the vehicle speed V is higher than the second region, as shown by lines c and d, the engine speed ES
P is set so as to gradually increase from the second and third set values B and C set to a value larger than the first set value A to the maximum value.

The control operation of the control unit 16 will be described with reference to the flow chart shown in FIG. When the control operation is started, the detected values such as the engine speed ESP, the throttle opening TVO and the vehicle speed V are input (step S1). Then, it is determined whether or not the rapid acceleration is required in accordance with the throttle opening TVO, that is, the throttle opening TVO is in a state in which the throttle opening TVO is largely opened beyond a preset reference value (kick down position). It is determined whether or not (step S2).

As a result of the above judgment, when it is confirmed that the driver does not request the rapid acceleration, the value NM corresponding to the engine speed ESP read from the normal map shown in FIG. 7 is set as the control reference value. N (step S3), the target gear ratio R of the continuously variable transmission 1 is calculated based on the control reference value N and the vehicle speed V (step S4), and the control signal corresponding to the target gear ratio R is set. The shift control unit 18 outputs the shift control unit 12 to perform shift control (step S).
5).

If it is determined YES in step S2 and it is confirmed that the driver is requesting rapid acceleration, it is determined whether the vehicle speed V is in the first region below the first reference vehicle speed V1. It is determined (step S6). As a result of this determination, when it is confirmed that the vehicle speed V is in the first region, the value N1 corresponding to the engine speed ESP read based on the line a in FIG. 3 is set as the control reference value N. (Step S7).

As a result of the above judgment, when it is confirmed that the vehicle speed V is not in the first region, it is judged whether or not it is in the second region below the second reference vehicle speed V2 (step S8), and the vehicle speed V is determined.
Is confirmed to be in the second region, the value N2 corresponding to the engine speed ESP read based on the line b in FIG. 3 is set as the control reference value N (step S
9). Similarly, when it is confirmed that the vehicle speed V is in the third region, the value N3 corresponding to the engine speed ESP read based on the line c in FIG. 3 is set as the control reference value N.
Set as. (Steps S10 and 11).

When it is determined NO in step S10 and it is confirmed that the vehicle speed V is equal to or higher than the third reference vehicle speed V3, it is determined that the vehicle is in the fourth region and the reading is performed based on the line d in FIG. After setting the value N4 corresponding to the determined engine speed ESP as the control reference value N, the above step S
Then, the process proceeds to step 4 (step S12).

The shift control during the sudden acceleration is performed in step S2.
At the time when it is confirmed that the opening degree of the accelerator pedal becomes smaller than the kick down position in,
The normal shift control state is entered. A detection means for detecting the amount of change in the accelerator opening is provided, and when it is confirmed by this detection means that the accelerator opening is in a decreasing tendency, the shift control state during the sudden acceleration is changed to the normal shift control. It may be configured to shift to the state.

As described above, the determination means 19 determines whether or not the driver is requesting the sudden acceleration in accordance with the throttle opening TVO, and when it is confirmed that the rapid acceleration is requested, as shown in FIG. As shown in (4), the control reference value is read from a graph preset so that the vehicle speed V increases while the engine speed ESP is gradually increased and suddenly decreased, and the gear shift control is executed corresponding to this value to change the gear shift. Since the ratio is changed stepwise, the low speed region (first
In the region), the engine speed ESP can be rapidly increased to the maximum value. Therefore, a large driving force is exerted in the low vehicle speed range, and excellent acceleration is obtained.

Then, when the vehicle speed V increases to the first reference vehicle speed V1, the line b from the control state of the first region shown by the line a above.
When the engine speed ESP is drastically decreased from the maximum value to the first set value A at the time of the shift to the control state of the second region shown by, and the gear shift is performed in the upshift direction, the engine speed ESP is increased with the vehicle speed V The rotation speed ESP gradually increases, and the vehicle speed V increases while such a change is repeated for each region.

Further, when it is confirmed by the judging means 19 that the driver does not request the rapid acceleration, the normal shift control based on the control map set so as to obtain the optimum driving force is performed. By executing this, an appropriate driving force corresponding to the throttle opening TVO is applied. Therefore, it is possible to effectively prevent a reduction in fuel consumption due to the transmission of unnecessary driving force.

In the above-described embodiment, as shown in FIG. 3, the gear change at the time of a sudden acceleration request is made based on the lines a to d which are set so that the gear ratio gradually increases in the high engine speed region of the engine speed ESP. Although the example configured to execute the control has been described, as shown in FIG. 5, while maintaining the gear ratio constant,
It may be configured to execute the shift control for increasing the engine speed ESP in proportion to the vehicle speed V.

In the above embodiment, the control characteristic changes when the vehicle speed V passes the reference vehicle speeds V1, V2 and V3, regardless of whether the vehicle is in the speed increasing state or the decelerating state. However, hysteresis may be provided by setting the reference vehicle speed when the vehicle speed increases and the reference vehicle speed when the vehicle speed decreases to different values. In this case, when the engine speed ESP is gradually increased or decreased in the high engine speed region, it is possible to prevent the control state of the gear ratio from being frequently switched, whereby the sudden change of the engine speed is repeated. The occurrence of such a situation can be prevented.

The present invention is not limited to the V-belt type continuously variable transmission, but can be applied to various types of continuously variable transmissions. For example, as shown in FIG. 6, in the vehicle having the first and second power transmission paths 23 and 24 which are switched by the path switching clutch 22 installed on the output side of the engine 21, the second power transmission path 24 is provided. The configuration of the present invention can be applied to the pair of front and rear toroidal type transmissions 25 provided in the.

The toroidal type transmission 25 has a pair of disks 26, 2 which are axially spaced from each other.
7 and a roller 28 disposed between both discs 26 and 27 and slidably contacting them, the output side disc 26 of the two discs is fixed to the output shaft 28, and the input side disc 27 is the above. It is supported so as to be rotatable relative to the output shaft 29 and movable in the axial direction. Then, the roller 28 is tilted by a hydraulic mechanism, and its installation angle θ is changed.
The sliding contact portion with respect to 27 is displaced so that the gear ratio is changed.

Since the toroidal type transmission 25 has a characteristic that the response of the shift control is excellent, the rapid acceleration control means 20 is provided to change the gear ratio stepwise when the rapid acceleration is requested. By adopting the configuration of the present invention as described above, there is an advantage that the shift control corresponding to the control characteristics preset for each vehicle speed region can be executed quickly and appropriately.

In the above embodiment, the throttle opening T
It is arranged to indirectly detect whether or not the accelerator pedal has been operated above a preset kickdown position according to the change state of VO. However, instead of this configuration, the accelerator pedal is operated above the kickdown position. It may be configured to determine whether or not the driver is requesting rapid acceleration, according to the output signal of the accelerator pedal sensor that directly detects that the vehicle has been accelerated.

[0033]

As described above, according to the present invention, the determination means determines whether or not the driver is requesting rapid acceleration according to the throttle opening, and confirms that rapid acceleration is requested. In this case, the control reference value is read from a graph preset so that the vehicle speed increases while the engine speed repeatedly increases and decreases rapidly, and the gear ratio is changed by executing the gear change control corresponding to this value. Since it is configured to change in a stepwise manner, the engine speed can be increased rapidly in the low speed region, which can exert a large driving force to accelerate the vehicle body quickly.
The engine speed can be increased as the vehicle speed increases.

Therefore, it is possible to prevent the occupant from feeling uncomfortable due to a situation in which only the vehicle speed increases without increasing the engine speed, while providing excellent acceleration response and high engine speed. There is an advantage that it is possible to effectively prevent the generation of noise due to being maintained in the rotation region for a long time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a drive system of a vehicle having a shift control device for a continuously variable transmission according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control unit of the shift control device.

FIG. 3 is a graph showing an example of a control map used when a sudden acceleration is requested.

FIG. 4 is a flowchart showing a control operation in the control unit.

FIG. 5 is a graph showing another example of a control map used when a sudden acceleration is requested.

FIG. 6 is a schematic diagram showing a drive system of a vehicle including a toroidal type continuously variable transmission.

FIG. 7 is a graph showing a control map used during normal shift control.

FIG. 8 is a graph showing a conventional example of a control map used when a sudden acceleration is requested.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 continuously variable transmission 12 speed change drive section 17 reference value setting means 18 speed change control means 19 determination means 20 sudden acceleration control means 25 toroidal type transmission 26, 27 disk 28 roller

Claims (2)

[Claims] 1. A reference value setting means for setting a control reference value based on a preset control map, and a shift drive for changing a gear ratio of a continuously variable transmission based on a shift target value corresponding to the control reference value. And a determination means for determining whether or not a rapid acceleration is required according to an operation amount of an accelerator pedal, and a determination for rapid acceleration in the determination means. When it is confirmed that the state is in a state, a sudden acceleration control means for gradually changing the speed change ratio is provided so as to increase the vehicle speed while repeating gradual increase and sudden decrease of the engine speed. Shift control device for continuously variable transmission. 2. A continuously variable transmission has a pair of disks, which are installed to face each other, and a roller, which is arranged between the disks. By adjusting the position where the rollers abut on the disk. The shift control device for a continuously variable transmission according to claim 1, wherein the shift control device comprises a toroidal transmission that changes a gear ratio.