JP2007040476A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve both suppression of shift shock and suppression of deterioration of fuel consumption by appropriately matching the start timing of the inertia phase and the release timing of the lockup clutch at the time of shifting.
When it can be said that the release timing of the lockup clutch is late with respect to the start timing of the inertia phase, the ECT_ECU reduces the learning value L that defines the timing for starting the release of the lockup clutch. A program that includes a correction step (S180) and a correction step (S200) that increases the learning value L when it can be said that the lock-up clutch release timing is earlier than the inertia phase start timing. Execute. When the learning value L is reduced, the timing for outputting the lock-up clutch release instruction is advanced. When the learning value L is increased, the timing for outputting the lock-up clutch release instruction is delayed.
[Selection] Figure 4

Description

  The present invention relates to an automatic transmission control device, and more particularly to an automatic transmission control device including a lock-up clutch that can directly connect an input side and an output side of a torque converter.

  Conventionally, an automatic transmission having a lock-up clutch is known. This lock-up clutch is engaged in a predetermined traveling state in order to improve fuel consumption. By engaging the lockup clutch, the input side and the output side of the torque converter are directly connected, and transmission loss of driving force in the torque converter is suppressed. On the other hand, if a shift of the automatic transmission is performed with the lock-up clutch engaged, a shift shock may occur. Therefore, the engaged lock-up clutch is temporarily released during the shift of the automatic transmission.

  Japanese Patent Application Laid-Open No. 5-172239 (Patent Document 1) discloses a lockup control device for an automatic transmission that can prevent a shift shock during a shift in a lockup state. The lockup control device described in this publication includes a lockup clutch that can mechanically directly connect the input side and the output side of the torque converter according to the lockup control amount, and the lockup control amount can be controlled in a predetermined operation range. This is a lockup control device for an automatic transmission which is increased to engage a lockup clutch. This lockup control device includes a shift command detection unit that detects a shift command during engagement of the lockup clutch, and reduces the lockup control amount to the lowest initial intermediate value within a range in which the lockup clutch does not slip when the shift command is detected. A first lockup control amount setting unit for causing the inertia phase detection unit to detect a transition from the torque phase to the inertia phase after detection of the shift command, and gradually increasing the lockup control amount from the initial intermediate value after detection of the inertia phase. And a second lockup control amount setting unit that lowers the lockup clutch to make it slip.

According to the lockup control device described in this publication, when a shift command is detected while the lockup clutch is engaged, the lockup control amount is reduced to the lowest initial intermediate value within a range in which the lockup clutch does not slip, and waits. . Thereafter, after detecting the transition to the inertia phase, the lockup control amount is gradually decreased from the initial intermediate value to bring the lockup clutch into a slipping state. As a result, it is possible to prevent the occurrence of shock by shifting to the sliding state with good response and smoothness at an appropriate timing.
JP-A-5-172239

  However, when the lockup clutch is released after detecting that the inertia phase has started, as in the lockup control device described in Japanese Patent Laid-Open No. 5-172239, the lockup occurs due to a response delay of the hydraulic oil. There was a problem that the release of the up-clutch was delayed and a shift shock could occur. Therefore, it is conceivable to start releasing the lockup clutch after a predetermined time elapses after the shift instruction to the automatic transmission and complete the release of the lockup clutch in accordance with the start timing of the inertia phase. However, the start timing of the inertia phase and the release timing of the lock-up clutch may differ depending on variations in components and changes with time. For this reason, it is difficult to complete the release of the lockup clutch in accordance with the start timing of the inertia phase. If the lock-up clutch is released too early, the fuel consumption and the like may deteriorate.

  The present invention has been made to solve the above-described problems, and its purpose is to appropriately adjust the start timing of the inertia phase and the release timing of the lock-up clutch, thereby suppressing the shift shock and deteriorating the fuel consumption. It is an object of the present invention to provide a control device for an automatic transmission that can achieve both suppression of noise.

  According to a first aspect of the present invention, there is provided an automatic transmission control apparatus that controls an automatic transmission that includes a lockup clutch that can directly connect an input side and an output side of a torque converter. The control device includes an instruction means for instructing release of the lockup clutch when a predetermined time has elapsed from a shift instruction to the automatic transmission, and a release detection means for detecting the release of the lockup clutch. In order to reduce the difference between the start detection means for detecting the start of the inertia phase in the automatic transmission, and the timing at which the start of the inertia phase is detected and the timing at which the release of the lockup clutch is detected. Correction means for correcting a predetermined time.

  According to the first invention, when a predetermined time elapses from a shift instruction to the automatic transmission, the release of the lockup clutch is instructed. For example, the lockup is performed based on the difference between the engine speed and the turbine speed. Clutch release is detected. Further, for example, the start of the inertia phase in the automatic transmission is detected from the turbine speed (from a drop in the turbine speed). At this time, if the timing at which the lockup clutch is released (the release of the lockup clutch is completed) is too late with respect to the start of the inertia phase, a shift shock may occur. On the other hand, if the timing at which the lockup clutch is released is excessively early relative to the start of the inertia phase, a time during which a transmission loss of driving force occurs in the torque converter increases, and fuel consumption may deteriorate. Therefore, a predetermined time for starting the release of the lockup clutch is corrected so as to reduce the difference between the timing at which the start of the inertia phase is detected and the timing at which the release of the lockup clutch is detected. . For example, when the timing at which the release of the lockup clutch is detected is later than a preset target timing, the preset time is corrected to be shortened. Conversely, when the timing at which the release of the lockup clutch is detected is earlier than a preset target timing, the preset time is corrected to be longer. As a result, it is possible to suppress the release timing of the lockup clutch from being excessively delayed or accelerated relative to the start timing of the inertia phase. Therefore, it is possible to provide a control device for an automatic transmission that can achieve both suppression of shift shock and suppression of deterioration of fuel consumption by appropriately matching the start timing of the inertia phase and the release timing of the lockup clutch.

  In the control apparatus for an automatic transmission according to the second invention, in addition to the configuration of the first invention, when the correction means detects that the release timing of the lockup clutch is later than a preset target timing, Means for correcting to shorten the predetermined time is included.

  According to the second aspect of the invention, when the timing at which the release of the lockup clutch is detected is later than a preset target timing, the predetermined time for starting the release of the lockup clutch is corrected to be shortened. Is done. Thereby, it can suppress that the timing which a lockup clutch is released becomes late compared with the start of an inertia phase. Therefore, a shift shock can be suppressed.

  In the control apparatus for an automatic transmission according to the third invention, in addition to the configuration of the first invention, the correction means, when the timing at which the release of the lockup clutch is detected is earlier than the preset target timing, Means for correcting to increase the predetermined time is included.

  According to the third aspect of the invention, when the timing at which the release of the lockup clutch is detected is earlier than a preset target timing, the predetermined time for starting the release of the lockup clutch is corrected to be longer. Is done. As a result, it is possible to suppress the timing at which the lockup clutch is released too early compared to the start of the inertia phase. Therefore, deterioration of fuel consumption can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, a power train of a vehicle including a control device according to an embodiment of the present invention will be described. The control device according to the present embodiment is realized by an ECU (Electronic Control Unit) 1000 shown in FIG. More specifically, it is realized by a program executed by ECT (Electrically Controlled Transmission) _ECU 1020 included in ECU 1000. In the present embodiment, the automatic transmission is described as an automatic transmission that includes a torque converter and includes a planetary gear type transmission mechanism.

  As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, a planetary gear type transmission mechanism 300, and an ECU 1000.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft speed NE (engine speed NE) of engine 100 detected by engine speed sensor 400 and input shaft speed (pump speed) of torque converter 200 are the same.

  The torque converter 200 includes a lock-up clutch 210 that directly connects the input shaft and the output shaft, a pump impeller 220 on the input shaft side, a turbine impeller 230 on the output shaft side, and a one-way clutch 250. It is comprised from the stator 240 which expresses an amplification function. Torque converter 200 and planetary gear type transmission mechanism 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by a turbine rotational speed sensor 410. The output shaft rotational speed NOUT of the planetary gear type speed change mechanism 300 is detected by the output shaft rotational speed sensor 420.

  FIG. 2 shows an operation table of the automatic transmission. According to the operation table shown in FIG. 2, the clutch elements (C1 to C4 in the figure), the brake elements (B1 to B4), and the one-way clutch elements (F0 to F3) that are friction elements are in any gear. Shows what is combined and released. At the first speed used when the vehicle starts, the clutch element (C1) and the one-way clutch elements (F0, F3) are engaged. Among these clutch elements, the clutch element C1 is particularly referred to as an input clutch 310. The input clutch 310 is also referred to as a forward clutch or a forward clutch, and as shown in the operation table of FIG. 2, the vehicle moves forward except for the parking (P) position, the reverse traveling (R) position, and the neutral (N) position. Is used in an engaged state when configuring a shift stage for the purpose.

  The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100 and an ECT_ECU 1020 that controls the automatic transmission.

  The ECT_ECU 1020 receives a signal representing the turbine rotational speed NT from the turbine rotational speed sensor 410 and a signal representing the output shaft rotational speed NOUT from the output shaft rotational speed sensor 420. The ECT_ECU 1020 also sends a signal representing the engine speed NE detected by the engine speed sensor 400, a signal representing the throttle opening detected by the throttle position sensor, and the shift position sensor 430 from the engine ECU 1010. The signal indicating the position of the shift lever 1012 detected in this way and the signal indicating the depression amount of the accelerator pedal 1014 detected by the accelerator opening sensor 440 are input.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the planetary gear type transmission mechanism 300. These rotational speed sensors are sensors that can detect slight rotations of the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the planetary gear type speed change mechanism 300. It is a sensor using a magnetoresistive element called a sensor. Further, a signal representing the vehicle speed detected by the vehicle speed sensor 450 is input to the ECT_ECU 1020.

  A control structure of a program executed by ECT_ECU 1020 of ECU 1000 that is the control device according to the present embodiment will be described with reference to FIGS. 3 and 4.

  In step (hereinafter, step is abbreviated as S) 100, ECT_ECU 1020 determines whether or not shifting of the automatic transmission is necessary. Whether or not a shift is necessary is determined based on, for example, a shift diagram defined by using the accelerator opening and the vehicle speed as parameters. If a shift is necessary (YES in S100), the process proceeds to S110. Otherwise (NO in S110), this process ends.

  In S110, ECT_ECU 1020 outputs a shift instruction to the automatic transmission. In S120, ECT_ECU 1020 starts counting the elapsed time after outputting the shift instruction to the automatic transmission.

  In S130, ECT_ECU 1020 determines whether or not lockup clutch 210 is engaged. Whether or not the lockup clutch 210 is to be engaged is determined by the ECT_ECU 1020 itself. Therefore, whether or not the lockup clutch 210 is in an engaged state is determined inside the ECT_ECU 1020. If lock-up clutch 210 is engaged (YES at S130), the process proceeds to S140. Otherwise (NO at S130), this process ends.

  In S140, ECT_ECU 1020 determines whether or not the elapsed time from the output of the shift instruction to the automatic transmission has exceeded set time T + learned value L. If the elapsed time after outputting the shift instruction to the automatic transmission exceeds set time T + learned value L (YES in S140), the process proceeds to S150. If not (NO in S140), the process returns to S140.

  In S150, ECT_ECU 1020 outputs an instruction to release lockup clutch 210. That is, the ECT_ECU 1020 starts to release the lockup clutch 210 by reducing the instruction value of the engagement hydraulic pressure of the lockup clutch 210.

  In S160, ECT_ECU 1020 outputs time TINASTART from the output of the shift instruction of the automatic transmission to the start of the inertia phase in the automatic transmission and the shift instruction of the automatic transmission, and then lockup clutch 210 is released. Time TLUOFF is measured. ECT_ECU 1020 determines that the inertia phase has started, for example, when the rate of decrease in turbine speed NT is greater than a threshold value, and determines that the inertia phase has started after outputting a gear shift instruction for the automatic transmission. The time until this is measured as time TINASTART. ECT_ECU 1020 determines that lock-up clutch 210 has been released when, for example, a time period in which the difference between engine speed NE and turbine speed NT is greater than a threshold value continues for a predetermined time or longer, automatic The time from when the shift instruction of the transmission is output until it is determined that the lockup clutch 210 is released is measured as the time TLUOFF.

  In S170, ECT_ECU 1020 determines whether time TINASTART-time TLUOFF <threshold-α. That is, it is determined whether or not the release timing of the lockup clutch 210 is later than the target timing (time TINASTART−threshold value) at which the lockup clutch 210 is released. Α is a constant determined in advance to provide a dead zone.

  When time TINASTART-time TLUOFF <threshold-α (YES in S170), it is determined that the release timing of lockup clutch 210 is excessively late with respect to the start timing of the inertia phase, and the process proceeds to S180. It is. If not (NO in S170), the process proceeds to S190.

  In S180, ECT_ECU 1020 corrects learning value L to be small. The ECT_ECU 1020 corrects the learning value L to be smaller by subtracting a predetermined value from the learning value L, for example.

  In S190, ECT_ECU 1020 determines whether time TINASTART-time TLUOFF> threshold value + α. That is, it is determined whether or not the release timing of the lockup clutch 210 is earlier than the target timing (time TINASTART−threshold) at which the lockup clutch 210 is released. If time TINASTART−time TLUOFF> threshold + α (YES in S190), it is determined that the release timing of lockup clutch 210 is excessively early with respect to the start timing of the inertia phase, and the process proceeds to S200. . Otherwise (NO in S190), this process ends.

  In S200, ECT_ECU 1020 corrects learning value L to be large. For example, the ECT_ECU 1020 corrects the learning value L to be larger by adding a predetermined value to the learning value L.

  An operation of ECT_ECU 1020 that is the control device according to the present embodiment based on the above-described structure and flowchart will be described.

  If it is determined from the shift diagram that a shift is necessary (YES in S100), a shift instruction to the automatic transmission is output (S110), and the process since the shift instruction to the automatic transmission is output. Time counting is started (S120).

  At this time, if the lock-up clutch 210 is in an engaged state, a shift shock may become significant during a shift. In order to suppress shift shock, when lockup clutch 210 is in the engaged state (YES in S130), the elapsed time after outputting the shift instruction to the automatic transmission is set time T + learned value L. If exceeded (YES in S140), a release instruction to lockup clutch 210 is output (S150). Thereby, the instruction value of the engagement hydraulic pressure of the lockup clutch 210 is reduced, and the release of the lockup clutch 210 is started.

  At this time, if the lock-up clutch 210 is released (the release of the lock-up clutch 210 is completed) too late with respect to the start of the inertia phase at the time of shifting of the automatic transmission, a shift shock may occur. .

  On the contrary, if the timing at which the lockup clutch 210 is released is excessively early with respect to the start of the inertia phase, a time during which a transmission loss of the driving force occurs in the torque converter 200 increases, and the fuel consumption may deteriorate.

  Therefore, the time TLUOFF from the time TINASTART until the inertia phase starts in the automatic transmission until the lockup clutch 210 is released from the time TINASTART until the inertia phase starts in the automatic transmission is output. If the subtracted time is smaller than threshold value −α (YES in S170), learning value L is decreased (S180).

  That is, when it can be said that the timing at which the lockup clutch 210 is released is excessively late relative to the timing at which the inertia phase starts, the gearshift instruction to the automatic transmission is output after the gearshift instruction to the automatic transmission is output. The time until output is shortened. Thereby, the timing at which the lockup clutch 210 is released can be advanced, and the difference between the timing at which the inertia phase starts and the timing at which the lockup clutch 210 is released can be reduced. Therefore, the occurrence of shift shock can be suppressed.

  Also, the time TLUOFF from the time TINASTART until the inertia phase is started in the automatic transmission until the lock-up clutch 210 is released after the time TINASTART is output from the time TINASTART until the inertia phase starts in the automatic transmission. If the subtracted time is larger than threshold value + α (YES in S190), learning value L is increased (S200).

  That is, when it can be said that the timing at which the lockup clutch 210 is released is excessively early with respect to the timing at which the inertia phase starts, the gearshift instruction to the automatic transmission is output after the gearshift instruction to the automatic transmission is output. The time until output is increased. Thereby, the timing at which the lockup clutch 210 is released can be delayed, and the difference between the timing at which the inertia phase starts and the timing at which the lockup clutch 210 is released can be reduced. Therefore, deterioration of fuel consumption can be suppressed.

  As described above, according to the ECT_ECU that is the control device according to the present embodiment, when it can be said that the timing at which the lockup clutch is released is excessively late with respect to the timing at which the inertia phase starts, the lockup is performed. The timing for outputting the clutch release instruction is advanced. Thereby, the timing at which the lockup clutch is released can be advanced, and the deviation between the timing at which the inertia phase starts and the timing at which the lockup clutch is released can be reduced. Therefore, the occurrence of shift shock can be suppressed. In addition, when it can be said that the timing at which the lockup clutch is released is excessively early with respect to the timing at which the inertia phase starts, the timing at which the lockup clutch release instruction is output is delayed. Thereby, the timing at which the lockup clutch is released can be delayed, and the difference between the timing at which the inertia phase starts and the timing at which the lockup clutch is released can be reduced. Therefore, deterioration of fuel consumption can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram of the automatic transmission according to the embodiment of the present invention. It is an operation | movement table | surface of the automatic transmission shown in FIG. It is a flowchart (the 1) which shows the control structure of the program performed by ECU which is a control apparatus which concerns on embodiment of this invention. It is a flowchart (the 2) which shows the control structure of the program performed by ECU which is a control apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Engine, 200 Torque converter, 210 Lock-up clutch, 300 Planetary gear type speed change mechanism, 400 Engine speed sensor, 410 Turbine speed sensor, 1000 ECU, 1010 Engine ECU, 1020 ECT_ECU.

Claims (3)

In an automatic transmission control device having a lock-up clutch capable of directly connecting the input side and the output side of a torque converter,
Instruction means for instructing release of the lock-up clutch when a predetermined time has elapsed from a shift instruction to the automatic transmission;
Release detecting means for detecting release of the lockup clutch;
Start detection means for detecting the start of inertia phase in the automatic transmission;
And an automatic transmission including correction means for correcting the predetermined time so as to reduce a difference between a timing at which the start of an inertia phase is detected and a timing at which the release of the lockup clutch is detected. Control device.   The said correction | amendment means contains a means for correct | amending so that the said predetermined time may be shortened, when the timing which detected releasing of a lockup clutch is later than the preset target timing. The automatic transmission control device described.   The said correction | amendment means includes a means for correct | amending so that the said predetermined time may be lengthened when the timing which detected releasing of a lockup clutch is earlier than the preset target timing. The automatic transmission control device described.

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