JP2007016967A - Control device and method for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve drivability by preventing the amount of kick-down from becoming excessive at sudden throttle opening. <P>SOLUTION: A computing section 23 computes target engine speed based on throttle opening TH and vehicle speed V. A determining section 28 determines whether throttle opening variation ΔTH is larger than a ΔTH decision value. When the variation ΔTH exceeds the ΔTH decision value, a small value is added to the throttle opening TH for retrieving the target engine speed. When the variation ΔTH is less than the ΔTH decision value, a large value is added to the throttle opening TH for retrieving the target engine speed. A map with the target engine speed Netgt increased with the enlargement of the throttle opening TH for retrieval is set into the computing section 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a continuously variable transmission control device and method, and more particularly to a continuously variable transmission control device suitable for obtaining smooth acceleration performance (drivability) by changing a shift characteristic in accordance with a change amount of a throttle opening. Regarding the method.

  In Japanese Patent Laid-Open No. 7-239016, when a vehicle in a specific driving state such as driving on a congested road or a residential area is removed from the specific driving state in a configuration in which a shift pattern is switched according to the driving state of the vehicle. In addition, there is disclosed a shift control device that delays the determination that the vehicle has deviated from a specific traveling state when there is no change in the preceding and following shift stages. According to this control, it is possible to avoid frequent changes in the running state determination parameter due to inadvertent accelerator operation, noise, or the like, thereby suppressing shift shock.

In addition, in a belt-type continuously variable transmission connected to an internal combustion engine (hereinafter referred to as “engine”), a control device that controls the pulley ratio by sliding the movable side of a drive pulley in the direction of the engine output shaft by a motor is known. (JP-A-6-123351). In this control device, a map is searched based on the throttle opening and the vehicle speed to determine a target ratio, and the motor is driven so that this target ratio is obtained. Further, the larger the difference between the target ratio and the actual pulley ratio, the larger the duty ratio of the motor, and the duty is controlled according to the on / off state of the accelerator. With this control, a smooth transmission operation in accordance with a shift request according to the driving situation is expected.
JP-A-7-239016 JP-A-6-123351

  In the continuously variable transmission control device of Patent Document 2, a target engine speed is obtained by map search based on the throttle opening and the vehicle speed, and the pulley ratio, that is, the gear ratio is controlled so as to reach the target engine speed. In this case, the target engine speed is uniquely determined by the throttle opening. Therefore, for example, when the throttle valve is suddenly opened under a shift characteristic suitable for normal running, an appropriate kickdown amount may not be obtained. For this reason, the running state does not change smoothly, and drivability may be reduced.

  An object of the present invention is to provide a continuously variable transmission control device and method capable of obtaining an appropriate amount of change in gear ratio regardless of the opening / closing speed of a throttle valve.

  To achieve the above object, the present invention provides a continuously variable transmission control method for determining a target engine speed of a continuously variable transmission mounted on a vehicle according to a throttle opening and a vehicle speed, wherein the throttle opening is large. As the target engine speed is increased, and the amount of change in the throttle opening per predetermined time is larger than a threshold value corresponding to the vehicle speed, a first value is set as the throttle opening for determining the target engine speed. When the amount of change in the throttle opening per predetermined time is smaller than the threshold value, a second value larger than the first value is added to the throttle opening for determining the target engine speed. There is a feature in the point.

  According to the present invention having the above characteristics, in order to determine the target engine speed according to whether or not the amount of change in throttle opening per predetermined time is larger than a threshold value set in advance according to the vehicle speed. Correct the throttle opening used. That is, when the amount of change in the throttle opening is larger than the threshold value, a small value is added to the throttle opening for determining the target engine speed. On the other hand, when the amount of change in throttle opening is smaller than the threshold value, a larger value is added to the throttle opening for determining the target engine speed. As described above, when the throttle is suddenly opened, the throttle opening for determining the target engine speed is made smaller than during normal throttle operation. Accordingly, since the target engine speed is prevented from suddenly increasing even when the throttle is suddenly opened, the kickdown amount does not become too large.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a system configuration diagram of a continuously variable transmission control device according to an embodiment of the present invention. The continuously variable transmission 1 is coupled to, for example, a crankshaft, that is, an output shaft 2 of an engine (not shown) that is a drive source of a scooter. The drive pulley 3 includes a fixed pulley piece 31 and a movable pulley piece 32 provided so as to be slidable in the axial direction with respect to the output shaft 2. A slider 5 is supported on the outer periphery of the hub of the movable pulley piece 32 via a bearing 4. A gear 51 is formed on the outer periphery of the slider 5, and the gear 51 meshes with the final gear 64 of the speed reducer 6 including four gears 61, 62, 63, 64, and the first gear of the speed reducer 6. 61 meshes with the output gear 71 of the motor 7. The female screw formed on the inner periphery of the slider 5 is screwed with the male screw formed on the outer periphery of the cylindrical body 9 fixed to the case 8.

  When the slider 5 is rotated by the rotation of the motor 7, the female screw of the slider 5 is rotated around the male screw of the cylindrical body 9, and the slider 5 is moved in the axial direction of the output shaft 2 by the feeding action in the axial direction of the screw. Moved. As the slider 5 moves, the distance between the fixed pulley piece 31 and the movable pulley piece 32 of the drive pulley 3 changes.

  The passive pulley 10 of the continuously variable transmission 1 is supported on the passive shaft 11. The passive pulley 10 includes a movable pulley piece 101 and a fixed pulley piece 102, both of which are rotatable with respect to the passive shaft 11. Further, the movable pulley piece 101 is slidable in the axial direction with respect to the passive shaft 11 and is biased toward the fixed pulley piece 102 by a coil spring 103. The passive shaft 11 is provided with a centrifugal clutch 12, and the movable pulley piece 101 is coupled to the passive shaft 11 through the clutch 12. The passive shaft 11 is coupled to the drive shaft of the scooter via a reduction gear including a gear 13. A V belt 14 is hung on the driving pulley 3 and the passive pulley 10.

  A position sensor 15 for detecting the reset position of the movable pulley piece 32 of the drive pulley 3 is provided close to the outer periphery of the movable pulley piece 32. In addition, a passive pulley rotation speed sensor 16 that detects the rotation speed of the passive pulley 11 is disposed to face a magnetic body (not shown) that rotates together with the passive pulley 10.

  A transmission control ECU 17 that drives the motor 7 is provided as a control device for the continuously variable transmission 1. The transmission control ECU 17 includes a microcomputer and receives supply of power from the battery 18.

  The scooter is provided with a mode switch 19 for selecting a travel mode. The speed change characteristic is selected from a manual mode and a plurality of auto modes according to the travel mode. The change switch 20 outputs a change signal CH for switching the gear position up or down. The change switch 20 is enabled in the manual mode, and the gear position is selected according to the change signal CH. In the manual mode, the motor 7 is driven so as to set a predetermined pulley ratio for each gear position. The pulley ratio is the rotational speed N1 (N1 / N0) of the passive pulley 10 with respect to the rotational speed N0 of the drive pulley 3. The throttle sensor 21 detects a throttle valve opening of an engine (not shown) and outputs opening information TH. The engine speed sensor 22 detects a reluctator provided on a rotor of a generator (ACG) (not shown) connected to the output shaft of the engine and outputs the ACG speed, that is, the engine speed Ne.

  The travel mode will be described. A plurality of travel modes are set, and different shift characteristics correspond to each travel mode. In the present embodiment, a sports mode and a low fuel consumption mode are set as a manual mode and two auto modes.

  FIG. 10 shows an example of shift characteristics in the low fuel consumption travel mode, and FIG. 11 shows an example of shift characteristics in the sport mode.

  In the manual mode, a plurality of gear ratios are set. One of the plurality of gear ratios is instructed by the change switch 18, and the gear ratio is set to be fixed so that the vehicle can travel.

  In the sport driving mode, powerful driving is possible at a higher engine speed than in the normal driving mode. In the fuel-efficient driving mode, driving at a lower engine speed than in the normal driving mode is contrary to the sports driving mode. It is set to be realized.

  FIG. 1 is a block diagram showing the main functions of the transmission control device (ECU 17). The target engine speed calculation unit 23 calculates the target engine speed Netgt based on the throttle opening TH and the vehicle speed V. For example, a map that outputs the target engine speed Netgt as a function value of the throttle opening TH and the vehicle speed V can be configured. This map is provided for each travel mode. The vehicle speed V can be represented by the rotational speed of the passive pulley 10 detected by the passive pulley rotational speed sensor 16.

  FIG. 9 is a diagram showing an example of a map for obtaining the target engine speed Netgt. This map is a three-dimensional map of the passive pulley speed (vehicle speed V), the throttle opening TH, and the target engine speed Netgt. Using this map, the value in the z direction at the intersection of the value in the x-axis direction (vehicle speed V) and the value in the y-axis direction (throttle opening TH) is read as a value indicating the target engine speed Netgt. In the example shown in FIG. 9, when the vehicle speed V increases to some extent, the degree of increase in the target engine speed Netgt accompanying the increase in the vehicle speed V increases. That is, on the side where the throttle opening TH is small, the increase amount of the target engine speed Netgt is large from when the vehicle speed V becomes V1. Further, on the side where the throttle opening TH is larger, the increase amount of the target engine speed Netgt is larger than when the vehicle speed V is V2 (V2 <V1).

  As a result, in this example, as a whole, the map is set so that the target engine speed Netgt becomes larger on the side where the throttle opening TH is larger.

  The motor control value determination unit 24 is a speed change characteristic determination unit, and is based on the difference between the target engine speed Netgt calculated by the target engine speed calculation unit 23 and the actual engine speed Ne obtained by the engine speed sensor 22. The rotational direction of the motor 7 and the duty, that is, the speed of the motor 7 are determined. If the target engine speed Netgt is higher than the actual engine speed Ne, the motor 7 is driven in the direction of increasing the interval between the fixed pulley 31 and the movable pulley 32 in order to increase the pulley ratio. The motor 7 is driven according to the control value output from the motor control value determination unit 24, that is, the rotation direction of the motor 7 and the target engine speed Netgt, and the pulley ratio is changed.

  Furthermore, in order to obtain an appropriate kickdown amount when the throttle is suddenly opened, the throttle opening is corrected when the throttle is suddenly opened and during normal acceleration. The output of the throttle sensor 21 is added and corrected by the adding unit 25. For example, in the memories 26 and 27 that can be configured by FIFO, the throttle opening TH is read for each predetermined interrupt cycle, and stored as the previous value and the current value.

  In the throttle opening change amount determination unit 28, the difference ΔTH between the previous value TH-1 and the current value TH0 of the throttle opening TH is compared with a predetermined ΔTH determination value, that is, a threshold value. The ΔTH determination value is set as a map as a function of the vehicle speed V in the ΔTH determination value storage unit 29. FIG. 3 shows an example of a map in which the relationship between the ΔTH determination value and the vehicle speed V is set.

  The throttle opening addition value is selected depending on whether the change ΔTH in the throttle opening is larger or smaller than the ΔTH determination value. A first addition value storage unit 30 storing a map of throttle opening addition value (addition value at sudden opening) when the throttle opening change ΔTH is larger than the ΔTH determination value, and the throttle opening change ΔTH from the ΔTH determination value A second addition value storage unit 31 is provided in which a map of throttle opening addition values (normal addition values) in the case of being small is stored. FIG. 4 shows an example of the map of the first addition value storage unit 30, and FIG. 5 shows an example of the map of the second addition value storage unit 31. The addition values respectively output from the first addition value storage unit 30 and the second addition value storage unit 31 according to the vehicle speed V are input to the addition unit 25.

  FIG. 6 is a flowchart of the throttle opening correction process. In step S1, the output of the passive pulley rotation speed sensor 16 is read as the vehicle speed V. In step S2, the ΔTH determination value corresponding to the vehicle speed is read from, for example, the map shown in FIG. In step S3, the throttle opening change amount ΔTH is calculated by subtracting the throttle opening previous value TH-1 from the throttle opening current value TH0. In step S4, it is determined whether or not the throttle opening change amount ΔTH is greater than or equal to a ΔTH determination value.

  If step S4 is affirmative, the routine proceeds to step S5, where the shift map search throttle opening addition value at the time of throttle sudden opening, that is, the sudden opening addition value is read from the first addition value storage unit 30 and set as the search addition value. . If step S4 is negative, the routine proceeds to step S6, where the shift map search throttle opening addition value during normal acceleration, that is, the normal addition value) is read from the second addition value storage unit 31 and set as the search addition value. In step S7, a value obtained by adding the search additional value to the throttle opening current value TH0 is set as the throttle opening TH. The target engine speed Netgt is retrieved using the throttle opening TH, and the motor 7 of the transmission 1 is driven and kicked down so as to obtain the target engine speed Netgt.

  As can be understood from FIG. 4 and FIG. 5, the sudden opening addition value is smaller than the normal addition value. Therefore, when the throttle opening TH0 is the same as the current throttle opening TH0, the target engine speed calculation unit 23 recognizes the throttle opening TH for searching when the throttle is suddenly opened as a value smaller than the throttle opening TH during normal acceleration. Is done.

  As a result, even when the throttle is suddenly opened, the target engine speed Netgt does not change greatly from the current value, and a sudden kickdown is suppressed.

  FIG. 7 shows changes in the throttle opening TH according to a conventional device in which the throttle opening TH used for the target engine speed search is not switched by the throttle opening change amount ΔTH, and the target engine rotation accompanying the change in the throttle opening TH. It is a figure which shows the change of the value for number searches. As shown in this figure, the throttle opening TH and the target engine speed search value are substantially the same. Therefore, when the throttle is suddenly opened, the target engine speed Netgt also changes abruptly, and the kickdown is larger than the appropriate state from the viewpoint of drivability.

  FIG. 8 shows changes in the throttle opening TH by the apparatus of this embodiment that switches the throttle opening TH used for the target engine speed search by the throttle opening change amount ΔTH, and the target engine accompanying the change in the throttle opening TH. It is a figure which shows the change of the value for rotation speed search. As shown in this figure, even if the throttle opening TH changes greatly, the target engine speed search value rises more slowly than its rise. Therefore, even when the throttle is suddenly opened, the target engine speed Netgt changes gently, and the kickdown is appropriate from the viewpoint of drivability.

It is a block diagram which shows the principal part function of the transmission control apparatus which concerns on one Embodiment of this invention. 1 is a system configuration diagram of a continuously variable transmission control device according to an embodiment of the present invention. It is a figure which shows an example of the map which set the relationship of (DELTA) TH determination value and vehicle speed. It is a figure which shows the example of the map of the addition value at the time of rapid opening. It is a figure which shows the example of the map of a normal time addition value. It is a flowchart of a throttle opening correction process. It is a figure which shows the value for a target engine speed search with the change of the throttle opening TH by the conventional apparatus which does not depend on throttle opening variation | change_quantity (DELTA) TH. It is a figure which shows the value for target engine speed search with the change of the throttle opening TH by the apparatus of one Embodiment switched by throttle opening variation | change_quantity (DELTA) TH. It is a figure which shows an example of the map for obtaining the target engine speed Netgt. It is a figure which shows an example of the speed change characteristic of low fuel consumption driving mode. It is a figure which shows an example of the speed change characteristic of a sports mode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Continuously variable transmission, 2 ... Crankshaft, 3 ... Drive pulley, 7 ... Motor, 14 ... V belt, 17 ... Transmission control ECU, 21 ... Throttle sensor, 23 ... Target engine speed calculation part, 25 ... Addition 28: Throttle opening change amount determination unit

Claims (3)

In a control device for a belt type continuously variable transmission mounted on a vehicle,
Means for detecting the throttle opening;
Means for detecting the speed of the vehicle;
Means for detecting the engine speed;
An actuator for changing the gear ratio,
Target value output means for outputting a larger target engine speed as the throttle opening is larger as a function of the throttle opening and the vehicle speed;
Shift characteristic determining means for determining a driving direction and a driving speed of the actuator based on the target engine speed and the actual engine speed;
Means for outputting a throttle opening change amount judgment value according to the vehicle speed;
Throttle opening change amount determination means for determining whether or not the throttle opening change amount for each predetermined processing cycle is larger than the throttle opening change amount determination value;
When the throttle opening variation is larger than the throttle opening variation determination value, the first throttle opening variation addition value is added to the throttle opening input to the target value output means, and the throttle opening variation is calculated. When the change amount is smaller than the throttle opening change amount determination value, the throttle opening that inputs a second throttle opening change addition value that is larger than the first throttle opening change addition value to the target value output means And a continuously variable transmission control device. In a continuously variable transmission control method for determining a target engine speed of a continuously variable transmission mounted on a vehicle according to a throttle opening and a vehicle speed,
While increasing the target engine speed as the throttle opening is larger,
When the amount of change in the throttle opening at a predetermined time is larger than a threshold value corresponding to the vehicle speed, a first value is added to the throttle opening for determining the target engine speed, and the throttle at every predetermined time is added. A continuously variable transmission control characterized by adding a second value larger than the first value to a throttle opening for determining the target engine speed when the amount of change in opening is smaller than the threshold value. Method. The continuously variable transmission has a drive pulley coupled to an output shaft of the engine and a passive pulley driven by a drive pulley by a V-belt;
2. The continuously variable transmission control device according to claim 1, wherein the actuator is means for changing a pulley ratio of the drive pulley and the passive pulley.

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