JP2001099290A - Speed change control device for continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform smooth speed change control without providing a driver with a feeling of physical disorder when speed change control is executed so that a target drive power is realized by using a pseudo-accelerator pedal operation amount. SOLUTION: This control device comprises a means 231 to compute the target number tNt of revolutions of an input shaft based on a target drive power; a means 232 to compute a pseudo accelerator pedaling degree conversion value VAPS corresponding to the target number tNt of revolutions of an input shaft; a means 234 to set a hysteresis Hys according to an operation state; a means 233 to compute a value, at which the hysteresis Hys is given to an accelerator pedaling degree conversion value VAPS as a correction accelerator pedaling degree conversion value VAPS1; and a means 235 to compute a target change gear ratio tRTO based on the correction accelerator pedaling degree conversion value VAPS1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a shift control device for a continuously variable transmission used in a vehicle or the like, and more particularly to a shift control according to a target value of a driving force.

[0002]

2. Description of the Related Art As a speed change control device of a continuously variable transmission used in a vehicle, a speed control device that controls a speed ratio based on a vehicle speed and an amount of depression of an accelerator pedal has been widely used. (Anti-lock brake system) and TCS (traction control system) have become widespread.
It is known to perform the operation based on the target driving force of the vehicle including the operation states of the BS and the TCS, and for example, there is JP-A-11-63188 proposed by the present applicant.

[0003] This is provided with a command device for integrally controlling the driving force of a vehicle, and this command device obtains a target driving force based on the driving state of the vehicle, and calculates a gear ratio and a target engine torque corresponding to the target driving force. In addition to the calculation, the target driving force or a target gear ratio and a target engine torque corresponding to the target driving force are commanded to the transmission control device and the engine control device. It controls a step transmission and an engine.

A continuously variable transmission for setting a gear ratio in accordance with a target driving force is disclosed in Japanese Patent Application No. Hei.
No. 0-289613, a target input shaft rotation speed is determined from a target driving force and a vehicle speed determined according to a driving state, and the target input shaft rotation speed is calculated by a preset map using a pseudo accelerator pedal operation amount. By converting to a certain accelerator pedal depression conversion value and obtaining the final target gear ratio based on this accelerator pedal depression conversion value, the driving state and the target driving force can be obtained while using the transmission control device of the conventional continuously variable transmission. It is possible to determine the gear ratio according to the speed ratio.

[0005] Further, there has been conventionally known a method of providing a hysteresis to an operation amount of an accelerator pedal when performing a shift control or an engine control of an automatic transmission, and a control command is issued in response to a driver's operation of the accelerator pedal. Prevents excessive fluctuations.

[0006]

However, in the above-described conventional transmission control apparatus for a continuously variable transmission, when the accelerator pedal depression degree conversion value is calculated from the target driving force and the target input shaft speed corresponding to the operating state. Although it is conceivable to provide a predetermined hysteresis, since the accelerator pedal depression conversion value uniquely corresponds to the target input shaft rotation speed, the maximum value of the accelerator pedal depression conversion value differs depending on the vehicle speed, When the predetermined hysteresis is set, for example, at a low vehicle speed, the ratio of the hysteresis becomes excessive, and when the actual accelerator pedal depression amount is small, no shift is performed. . On the other hand, if the hysteresis is set at low vehicle speeds, the dead zone becomes too narrow at high vehicle speeds, causing shifts to be performed even with a slight amount of accelerator pedal depression. There was a problem that would.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made to achieve a target driving force by using a pseudo accelerator pedal operation amount that uniquely corresponds to a target input shaft speed. An object of the present invention is to perform smooth shift control without giving a driver a sense of incongruity when performing shift control.

[0008]

According to a first aspect of the present invention, there is provided a target driving force calculating means for calculating a target driving force according to a driving state;
First target value calculating means for calculating a target input shaft speed or a target gear ratio based on the target driving force; and a pseudo accelerator pedal operation amount conversion value corresponding to an output of the first target value calculating means. Simulated manipulated variable conversion value calculation means, hysteresis setting means for setting hysteresis in accordance with the operating state, and calculating the corrected accelerator pedal operation amount conversion value by applying the hysteresis to the corrected accelerator pedal operation value conversion value. And a second target value calculating means for calculating a target input shaft rotation speed or a target gear ratio based on the corrected accelerator pedal operation amount conversion value.
Shift control means for controlling the gear ratio based on the output of the target value calculating means.

In a second aspect based on the first aspect, the hysteresis setting means sets the hysteresis small at a low vehicle speed, and increases the hysteresis at a high vehicle speed.

In a third aspect based on the second aspect, the hysteresis setting means calculates the hysteresis by multiplying a maximum value of an accelerator pedal operation amount conversion value for each vehicle speed by a preset ratio. It is characterized by doing.

[0011]

According to the first aspect of the present invention, when performing shift control in accordance with a target driving force, a pseudo accelerator pedal operation amount conversion value is associated with a target input shaft speed or a target speed ratio. When performing control, since the maximum value of the target input shaft rotation speed for each vehicle speed, in other words, the maximum value of the accelerator pedal operation amount conversion value is also different, if the hysteresis is fixed as in the conventional example, at low vehicle speeds, The gear shift does not occur unless the accelerator pedal depression amount is largely changed.At high vehicle speeds, the gear shift occurs in response to a slight change in the accelerator pedal depression amount, whereas the hysteresis added to the accelerator pedal operation amount conversion value is changed to the driving state. The target driving force can be obtained while performing gear shifting according to the driver's intention regardless of the vehicle speed.

In the second and third inventions, the hysteresis is set to be small at low vehicle speeds, and the hysteresis is set to be large at high vehicle speeds. Even for minute changes in the amount, the corrected accelerator pedal operation amount conversion value can be quickly raised to change the gear ratio, and at high vehicle speeds, the hysteresis increases as the vehicle speed increases. It is possible to prevent the gear ratio from gradually increasing and prevent the gear ratio from excessively changing in response to a slight change in the accelerator depression amount, thereby improving drivability.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example in which a toroidal type continuously variable transmission is adopted as a continuously variable transmission. An engine controller 4 for controlling the engine 1 and a continuously variable transmission 1
0 is connected via communication means such as a LAN.

The engine controller 4 calculates a target driving force tFd according to the driving state of the vehicle and the like, controls the fuel injection amount and the ignition timing of the engine 1 based on the target driving force tFd, and controls the LAN and the like. The target driving force tFd is transmitted to the transmission control controller 2 via the communication means of the above, and the transmission control controller 2 controls the transmission ratio of the continuously variable transmission 10 based on the target driving force tFd.

The continuously variable transmission 10 is connected to the engine 1 via a torque converter T / C having a lock-up clutch L / U, and includes a step motor 3 as an actuator that responds to a command value of a transmission control controller 2. The speed ratio is continuously controlled via a hydraulic control device such as a speed control valve (not shown).

The shift control controller 2 reads the accelerator depression amount APS corresponding to the driver's operation of the accelerator pedal from the accelerator depression amount sensor 5 in addition to the target driving force tFd read from the engine control controller 4 and continuously variable transmission. Shaft rotation sensor 6 of machine 10
The controller reads the input shaft rotation speed Nt and the output shaft rotation speed No detected by the output shaft rotation sensor 7, respectively, and controls the stepping motor 3 so as to achieve a gear ratio corresponding to the target driving force tFd.

The accelerator depression amount sensor 5 detects, for example, a released state of the accelerator pedal as the accelerator depression amount APS = 0 °, and detects a fully opened state of the accelerator pedal as the accelerator depression amount APS = 90 °.

Here, the engine control controller 4
2, the speed ratio detection unit 33 calculates the actual speed ratio from the ratio between the input shaft speed Nt and the output shaft speed No of the continuously variable transmission 10, and the vehicle speed detection unit 34 The vehicle speed VSP is calculated by multiplying the output shaft rotation speed No of the step transmission 10 by a predetermined constant (final gear ratio, tire radius, etc.).

The target driving force determining unit 31 determines the vehicle speed V
Based on SP and accelerator depression amount APS, target driving force tFd corresponding to detected vehicle speed VSP using accelerator depression amount APS as a parameter based on the map shown in FIG.
Is calculated.

The target engine torque determining section 32 determines the target engine torque tTe according to the target driving force tFd and the actual gear ratio detected by the gear ratio detecting section 33.

The engine torque control unit 36 controls the fuel injection amount and the ignition timing so that the target engine torque tTe determined by the target engine torque determination unit 32 is obtained.

On the other hand, the transmission controller 2 connected to the engine controller 4 via the LAN determines the target transmission ratio tRTO based on the target driving force tFd, as shown in FIG.

In FIG. 2, the transmission control controller 2
Is a speed ratio detecting unit 2 that calculates an actual speed ratio from the ratio of the input shaft speed Nt of the continuously variable transmission 10 to the output shaft speed No.
1, a vehicle speed detecting unit 22 for calculating the vehicle speed VSP by multiplying the output shaft rotation number No by a predetermined constant, a target driving force tFd read via the LAN, and a target shift from the accelerator depression amount APS and the vehicle speed VSP. A target gear ratio determining unit 23 for calculating the ratio tRTO;
And a speed ratio control unit 24 that drives the step motor 3 so that the actual speed ratio matches the actual speed ratio.

Further, details of the target gear ratio determining unit 23 are as follows.
It is configured as shown in FIG.

First, the target input shaft rotational speed calculating section 231 (first target value calculating means) uses the target driving force tFd read from the engine control controller 4 as a parameter, according to the vehicle speed VSP according to the map shown in FIG. The target input shaft speed tNt is calculated.

Next, the pseudo accelerator opening calculating section 232 (pseudo operation amount conversion value calculating means) calculates the target input shaft rotational speed tNt based on the map of FIG. Convert to pedaling conversion value VAPS,
Accelerator Depression Conversion Value VAPS and Target Input Shaft Speed tNt
Is uniquely associated.

Here, the conversion map of FIG. 7 shows that the target input shaft speed tNt obtained in FIG. 6 is the minimum target input shaft speed N in accordance with the vehicle speed VSP for each accelerator depression amount APS.
While changing from 1 to the maximum target input shaft speed N2, the accelerator pedal depression conversion value VAPS corresponding to the target input shaft speed tNt is converted to be constant regardless of the vehicle speed VSP. When the target input shaft rotation speed tNt is equal to or less than a predetermined minimum target input shaft rotation speed N1, VAPS =
On the other hand, when the rotation speed exceeds 0 °
APS = 90 °.

On the other hand, the hysteresis calculation section 234 (hysteresis setting means) calculates the accelerator pedal depression degree conversion value VAP.
In order to add hysteresis to S, a hysteresis value Hys corresponding to the vehicle speed VSP is calculated based on the map in FIG.

The map shown in FIG. 8 shows that when the vehicle speed VSP is low, the hysteresis value Hys is set small,
In a region where the vehicle speed VSP is high, the hysteresis value Hys is set in advance so as to increase.

Next, the corrected accelerator pedal depression degree conversion unit 233 (correction means) converts the converted accelerator pedal depression degree conversion value VAPS.
The hysteresis value Hys obtained by the hysteresis calculation unit 234 is assigned to the accelerator pedal depression degree conversion value VAPS uniquely corresponding to the target input shaft speed tNt as shown in FIG.
, A hysteresis value Hys corresponding to the vehicle speed VSP is added to calculate a corrected accelerator pedal depression degree conversion value VAPS1.

The hysteresis value Hys is, as shown in FIG. 9, an accelerator pedal depression degree conversion value VAPS according to its magnitude.
A dead zone corresponding to the vehicle speed VSP is given to the increasing side of the vehicle, while the obtained accelerator pedal depression conversion value VAP is obtained on the decreasing side.
A corrected accelerator pedal depression degree conversion value VAPS1 is set so as to be S.

Then, the correction target input shaft rotation speed calculating section 23
5 (second target value calculating means), as shown in the map of FIG. 10, the target input shaft rotational speed uniquely determined according to the corrected accelerator pedal depression degree conversion value VAPS1, and the corrected target input shaft rotational speed tNt1. Output as

The correction target input shaft rotation speed calculation unit 235
, The vehicle speed VSP is also input. This is for performing target driving force control using a conventional shift control device.
Instead of the map of the target input shaft rotation speed corresponding to the vehicle speed VSP and the accelerator depression amount APS, which has been performed in the conventional shift control, a map of the corrected accelerator pedal depression degree conversion value VAPS1 and the corrected target input shaft rotation speed tNt1 is adopted. In the map of FIG. 10, the input vehicle speed VSP is consequently ignored.

Thus, the corrected accelerator pedal depression conversion value VAP
The target gear ratio tRTO is obtained by dividing the corrected target input shaft rotation speed tNt1 corresponding to S1 by the output shaft rotation speed No.
This is sent to the speed ratio control unit 24 shown in FIG.

Here, the shift control performed by the shift controller 2 will be described in detail with reference to the flowchart of FIG. Note that the flowchart of FIG. 4 is executed every predetermined time, for example, every 10 msec.

First, in step S1 of FIG. 4, the accelerator depression amount APS from the accelerator depression amount sensor 5 and the input shaft rotation speed Nt and the output shaft rotation speed No from the continuously variable transmission 10 are read as the driving state of the vehicle. In step S2, the vehicle speed VSP is obtained by multiplying the output shaft rotation speed No by a predetermined conversion constant A.

Next, at step S3, the target driving force tFd is read from the engine controller 4 connected via the LAN.

In step S4, based on the map shown in FIG. 6, a target input shaft speed tNt corresponding to the vehicle speed VSP is calculated using the target driving force tFd as a parameter.

Next, in step S5, the accelerator pedal depression conversion value VAPS uniquely corresponding to the target input shaft rotation speed tNt is calculated based on the map of FIG. .

In step S6, a hysteresis value Hys corresponding to the vehicle speed VSP is calculated based on the map shown in FIG. 8, and when the vehicle speed VSP is low, the hysteresis value Hy is calculated.
While s is set small, in the region where the vehicle speed VSP is high,
The hysteresis value Hys is set so as to increase.

In step S7, the hysteresis value Hys obtained in step S6 is added to the accelerator depression degree conversion value VAPS obtained in step S5, and the detected vehicle speed VSP is calculated as shown in FIG. Corrected accelerator pedal depression conversion value VAP having hysteresis corresponding to the magnitude
S1 is calculated.

In this manner, the corrected accelerator pedal depression degree conversion value VAPS1 to which the hysteresis is added is converted into a correction target input shaft rotation speed tNt1 based on a preset map, as shown in FIG. In step S9, a value obtained by dividing the corrected target input shaft speed tNt1 by the output shaft speed No is calculated as the target speed ratio tRTO, and the actual speed ratio is calculated as the target speed ratio tRTO.
The step motor 3 is driven so as to coincide with.

As described above, the accelerator depression amount APS
And the target driving force tFd obtained according to the vehicle speed VSP,
After obtaining the target input shaft rotation speed tNt according to the vehicle speed VSP from the map of FIG. 6, the target input shaft rotation speed tNt is obtained.
Is converted into an accelerator pedal depression degree conversion value VAPS, which is a pseudo accelerator pedal operation amount, and this accelerator pedal depression degree conversion value VAP
When performing shift control in accordance with the target driving force tFd based on the vehicle speed S, the vehicle speed VS is compared with the accelerator pedal depression degree conversion value VAPS.
Hysteresis according to the magnitude of P is provided.

As shown in FIG. 9, the corrected accelerator pedal depression degree conversion value VAPS1 corrected by the hysteresis value Hys has a small dead zone because the hysteresis value Hys is small as shown by a solid line in FIG. Even when the accelerator pedal depression amount APS is minutely changed (in other words, a change in the target driving force tFd becomes the target input shaft speed tNt), the corrected accelerator pedal depression degree conversion value VAPS1 quickly rises and the corrected target input value VAPS1 rises. The shaft rotation speed tNt1 can be increased.

On the other hand, when the vehicle speed is high, the hysteresis value Hys increases in accordance with the increase in the vehicle speed VSP. Therefore, as shown by the broken line and the one-dot chain line in the drawing, the dead zone also gradually increases, and the accelerator depression amount APS becomes minute. Even if it changes, the rise of the correction target input shaft rotation speed tNt1 is delayed, so that it is possible to prevent the gear ratio from excessively changing according to a slight change in the accelerator depression amount APS.

In this manner, when performing shift control in accordance with the target driving force tFd, the maximum value of the target input shaft rotation speed tNt for each vehicle speed VSP, in other words, the accelerator pedal depression degree conversion value VA
Since the maximum value of PS is also different, when the hysteresis is fixed as in the above-described conventional example, no shift is performed unless the accelerator depression amount APS is largely changed at a low vehicle speed, and at a high vehicle speed, the slight accelerator depression amount APS is small. Although the shift occurs according to the change, as in the present invention, the hysteresis value Hys given to the accelerator depression degree conversion value VAPS is changed according to the vehicle speed VSP, and particularly, at a low vehicle speed, the hysteresis value Hys is small. Hysteresis value H at high vehicle speed
By setting ys to a large value, it becomes possible to perform shift control in accordance with the target driving force tFd without giving the driver an uncomfortable feeling, and the operability of the continuously variable transmission can be improved.

In the shift map shown in FIG. 10, the corrected accelerator pedal depression degree conversion value VAPS1 (corrected target input shaft rotation speed tN
Although the representative point of t1) is shown, the hysteresis value Hy
By performing interpolation in accordance with the magnitude of s, an arbitrary corrected target input shaft rotation speed tNt1 can be obtained, and the corrected accelerator pedal depression degree conversion value VAPS1 is constant regardless of the vehicle speed VSP. As indicated by the dashed line, the maximum Hi (minimum) limited by the mechanical limit of the continuously variable transmission 10
It does not exceed the gear ratio or the maximum Lo (maximum) gear ratio.

As shown in FIG. 11, the hysteresis value Hys given to the accelerator depression degree conversion value VAPS is the vehicle speed VSP and the accelerator depression degree conversion value VAPS that can be realized when the accelerator depression amount APS is the maximum (fully open). From the relationship, the value obtained by multiplying the maximum accelerator depression degree conversion value VAPS for each vehicle speed VSP shown by the solid line in the figure by a predetermined ratio α% may be used as the hysteresis value Hys. In this case, too, the hysteresis value Hys is It can be set small at low vehicle speeds and large at high vehicle speeds.

In the above embodiment, the case where the toroidal type continuously variable transmission is adopted as the continuously variable transmission has been described. However, a belt type continuously variable transmission may be used.

In the above embodiment, the case where the engine control controller 4 calculates the target driving force tFd has been described. You may connect.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a continuously variable transmission showing one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of an engine control controller and a shift control controller.

FIG. 3 is a schematic configuration diagram showing an example of a target gear ratio determining unit of the gear change control controller.

FIG. 4 is a flowchart of control performed by a shift control controller.

FIG. 5 is a map of a target driving force tFd according to a vehicle speed VSP and an accelerator pedal depression amount APS.

FIG. 6 is a map of a target input shaft rotation speed tNt according to a vehicle speed VSP and a target driving force tFd.

FIG. 7 is a map of an accelerator pedal depression degree conversion value VAPS corresponding to a target input shaft rotation speed tNt.

FIG. 8 is a map showing a relationship between a vehicle speed VSP and a hysteresis value Hys.

FIG. 9 is a map of a corrected accelerator pedal depression conversion value VAPS1 obtained by adding a hysteresis value Hys to an accelerator depression depression conversion value VAPS.

FIG. 10 is a map of a corrected accelerator pedal depression degree conversion value VAPS1 and a target input rotation speed tNt1.

FIG. 11 is a map of a hysteresis value Hys according to a vehicle speed VSP according to another embodiment.

[Explanation of symbols]

 2 Shift control controller 4 Engine control controller 5 Accelerator depression amount sensor 6 Input shaft rotation sensor 7 Output shaft rotation sensor 10 Continuously variable transmission

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 63:06 F16H 63:06 (72) Inventor Tetsu Takizawa 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Automobile Stock In-house (72) Inventor Masatoshi Akanuma Nissan Motor Co., Ltd., 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Shigeki Shimanaka 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture, Nissan Motor Co., Ltd. (72) Inventor Hiroyasu Tanaka 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. (72) Inventor Junya Takayama 2 Takara-cho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture Nissan Motor Co., Ltd. F-term (reference) 3J052 AA04 CA21 FA01 FB33 GC13 GC23 HA11 HA13 LA01

Claims (3)

[Claims] 1. A target driving force calculating means for calculating a target driving force according to an operation state; a first target value calculating means for calculating a target input shaft speed or a target gear ratio based on the target driving force; Pseudo operation amount conversion value calculation means for calculating a pseudo accelerator pedal operation amount conversion value corresponding to the output of the first target value calculation means; hysteresis setting means for setting hysteresis in accordance with an operating state; Correction means for calculating a value obtained by giving the hysteresis to the operation amount conversion value as a correction accelerator pedal operation amount conversion value; and calculating a target input shaft speed or a target gear ratio based on the correction accelerator pedal operation amount conversion value. Continuously variable transmission, comprising: a second target value calculating means for performing a speed change ratio control based on an output of the second target value calculating means. Gear shift control device. 2. The shift control device for a continuously variable transmission according to claim 2, wherein the hysteresis setting means sets the hysteresis small at a low vehicle speed and increases the hysteresis at a high vehicle speed. 3. The hysteresis according to claim 2, wherein the hysteresis setting means calculates the hysteresis by multiplying a maximum value of an accelerator pedal operation amount conversion value for each vehicle speed by a preset ratio. Transmission control device for a step transmission.