JP2008116005A - CONTROL DEVICE AND CONTROL METHOD FOR VEHICLE MOUNTED WITH AUTOMATIC TRANSMISSION WITH LOCK-UP CLUTCH, PROGRAM AND RECORDING MEDIUM FOR IMPLEMENTING THE CONTROL METHOD - Google Patents

Abstract

In a vehicle equipped with an automatic transmission having a lock-up clutch, the starting performance is improved when the power transmission action of a torque converter is reduced.
An ECU detects a shift position (S100), detects a brake switch state (S200), detects an output shaft rotation speed NOUT of an automatic transmission (S300), a shift When the position is the D or R position and the vehicle is stopped (YES in S400 and YES in S500), a step of detecting engine speed NE (S600) and a step of detecting engine fuel injection amount (S700) If the engine is idling and the engine load is smaller than the threshold value (YES in S800), it is determined that the power transmission action of the torque converter is reduced (S900), and the vehicle is started ( Step S1100: YES), slip-controlling the lockup clutch (S120) ) And a, to run the program.
[Selection] Figure 3

Description

  The present invention relates to control of a vehicle equipped with an automatic transmission, and more particularly to control for improving vehicle start performance using a lock-up clutch at a low temperature.

  There is an automatic transmission as an element constituting a power train of a vehicle. This automatic transmission has a fluid coupling such as a torque converter provided on the output side of the engine, a gear-type stepped transmission mechanism provided on the drive wheel side thereof, a continuously variable type such as a belt type and a traction type. And a transmission mechanism.

  The stepped transmission mechanism automatically switches the power transmission path based on, for example, the accelerator opening and the vehicle speed, and automatically switches the transmission gear stage. The belt-type continuously variable transmission mechanism automatically changes the gear ratio by changing the diameter of the pulley around which the belt is wound automatically based on the accelerator opening and the vehicle speed, for example.

  A vehicle having such an automatic transmission is provided with a shift lever operated by a driver, and a shift position (for example, reverse travel position, neutral position, forward travel position) is set based on the shift lever operation, Shift control is automatically performed within the shift position thus set (usually in the forward travel position).

  In addition to the torque converter, the fluid coupling includes a fluid coupling that has no stator and does not have a torque amplifying action. In these torque converters and fluid couplings, the rotation of the pump impeller on the engine side is transmitted to the rotation of the turbine runner on the transmission side through hydraulic oil sealed in the inside thereof.

  Furthermore, many torque converters include a lock-up clutch. The lock-up clutch mechanically directly connects a drive-side member (engine-side pump impeller) and a driven-side member (transmission mechanism-side turbine runner) of the torque converter. Therefore, both improvement in fuel consumption and riding comfort can be achieved. A lockup region in which such a lockup clutch is engaged is set based on, for example, the vehicle speed and the throttle opening. Further, the lockup clutch is controlled so that the engagement force (engagement pressure) of the lockup clutch according to the rotational difference between the pump speed on the input side (corresponding to the engine speed) and the turbine speed on the output side. Feedback control (slip control) to a predetermined state, and based on the learned value obtained at this time, the slip state of the torque converter is appropriately feedforward controlled to generate vibration and noise (NV: Noise & Vibration) There is known a technique for preventing the occurrence of the vehicle and improving the starting performance of the vehicle.

  In this way, through advanced electronic control, the power transmission distribution between the mechanical power transmission by the lock-up clutch and the power transmission by the torque converter is finely controlled according to the driving state, thereby greatly increasing the transmission efficiency. Yes. In other words, this lock-up clutch is controlled based on the driving state of the vehicle such as load and rotation. The area is set to the slip area. In the lockup region, the input element (pump impeller) and the output element (turbine runner) of the torque converter, which is a fluid transmission device, are completely fastened to improve fuel efficiency. In the converter region, the input element and the output element of the fluid transmission are completely released, and the torque is increased by the torque amplification function of the torque converter. In the slip region, the input element and the output element of the fluid transmission device are half-fastened so that both improvement in fuel efficiency and absorption of shock and vibration can be achieved.

  Japanese Patent Application Laid-Open No. 5-172237 (Patent Document 1) discloses a fail determination device for an automatic transmission that determines torque converter failure, mission lock, sensor failure, and the like. This automatic transmission failure determination device includes an automatic transmission in which a fluid coupling and a transmission are connected, an input shaft rotation speed detection unit that detects an input shaft rotation speed of the fluid coupling, and an output shaft rotation speed of the fluid coupling. An output shaft rotational speed detection unit for detecting, a traveling state detection unit for detecting a traveling state except immediately after starting, a slip ratio calculating unit for calculating a slip ratio that is a ratio of the output shaft rotational speed to the input shaft rotational speed, A fail judgment slip ratio setting unit that sets a fail judgment slip ratio that cannot be normal according to the gear ratio of the machine, and if the slip ratio calculation value is less than or equal to the fail judgment slip ratio at the time of running condition detection, A fail judging unit for judging that there is.

According to this automatic transmission failure determination device, when the vehicle is in a running state except immediately after starting, the failure determination unit detects the slip ratio calculated value from the slip ratio calculation unit when the traveling state detection unit detects the traveling state. When the ratio falls below the fail judgment slip ratio from the ratio setting unit, it is judged as a fail. Here, the slip ratio calculation unit outputs the output to the input shaft rotation speed based on the detection values from the input shaft rotation speed detection section and the output shaft rotation speed detection section that detect the input shaft rotation speed and the output shaft rotation speed of the fluid coupling. A slip ratio, which is a ratio of shaft speeds, is calculated. Further, in the fail judgment slip ratio setting unit, a slip ratio that cannot be normal is set as the fail judgment slip ratio according to the transmission gear ratio of the transmission. Therefore, when the calculated slip ratio is less than or equal to the fail judgment slip ratio, when the fluid coupling falls into a fail state, the transmission becomes an interlock, etc., at least one of the two rotation speed detectors fails. In such a case, it is determined as a failure.
JP-A-5-172237

  In a vehicle having such an automatic transmission, in a state where the forward traveling position is set and the vehicle is stopped, the driving force from the idling engine is transmitted to the transmission via the torque converter, which is the wheel. Therefore, a so-called creep phenomenon occurs. Creep phenomenon is very useful under certain conditions, such as smooth starting from a stop on an uphill road, but it is an unnecessary phenomenon when you want to keep the vehicle stopped, and it activates the vehicle brake To suppress the creep force.

  Thus, when the vehicle is stopped at the forward travel position (D position), the driving force from the engine that rotates idling is transmitted to the automatic transmission via the torque converter. In the stepped transmission mechanism, the friction engagement element is in a state of forming a first gear, for example, by being in the D position. In such a state, the vehicle is stopped by the brake. For this reason, the pump impeller on the input side (engine side) of the torque converter rotates, but the turbine runner on the output side (automatic transmission side) of the torque converter does not rotate.

  In addition, when the temperature of the hydraulic oil in the automatic transmission is low, the hydraulic oil has a high viscosity, so that the hydraulic oil is not sufficiently circulated inside the automatic transmission.

  Further, when the temperature of the hydraulic oil in the automatic transmission is low, the oil level in the oil pan is lowered, so that the hydraulic oil mixed with bubbles may be supplied into the automatic transmission. In such a state, if the time during which the turbine impeller of the torque converter is not rotating is long, bubbles are accumulated or accumulated in the torque converter. If there is such a bubble, the power transmission action of the torque converter will not function or the function will decrease, and the driving force will decrease when the vehicle restarts.

  Thus, if the temperature of the hydraulic oil of the automatic transmission is low, the power transmission function of the torque converter will not function or the function will be reduced, and the driving force will decrease when the vehicle starts (low temperature lost). It is also called the drive phenomenon).

  However, Patent Document 1 described above does not disclose any such phenomenon and lockup clutch.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an automatic transmission having a lock-up clutch that improves the starting performance when the power transmission action of the fluid coupling decreases. It is an object to provide a control device and a control method for a mounted vehicle, a program for realizing the control method, and a recording medium.

  The control device according to the first invention controls a vehicle equipped with an automatic transmission connected to a power source. The automatic transmission includes a fluid coupling connected to the output shaft of the power source and a transmission mechanism connected to the output shaft of the fluid coupling, and the fluid coupling includes a clutch that mechanically connects the input and output shafts. The control device includes a detecting means for detecting a decrease in the power transmission action of the fluid coupling, and when the reduction in the power transmission action is detected, the power of the power source is transmitted to the transmission mechanism using a clutch when the vehicle starts. Control means for controlling the engagement force of the clutch so as to transmit. The control method according to the fifth invention has the same requirements as the control device according to the first invention.

  According to the first or fifth invention, the temperature of the hydraulic oil of the automatic transmission is low, so that the viscosity increases and the amount of lubrication decreases, the level of the oil pan decreases and bubbles enter the hydraulic oil ( In particular, when the speed change mechanism is stopped at the D position or R position where the vehicle is running and the speed change mechanism side of the fluid coupling is not rotating), the power transmission action of the fluid coupling may be reduced. When starting the vehicle in such a case, the driving force transmitted from the power source to the speed change mechanism when the vehicle starts is insufficient only by the power transmission action of the fluid coupling (for example, torque converter). For this reason, using a clutch (lock-up clutch) that mechanically connects the input shaft (pump impeller) and the output shaft (turbine liner) of the torque converter, In addition / alternatively, the driving force is transmitted from the power source to the transmission mechanism by a mechanically connected clutch. In this way, even if the power transmission action of the fluid coupling is reduced, the driving force can be transmitted from the power source to the transmission mechanism by the clutch, so that a smooth start can be realized. As a result, it is possible to provide a control device and a control method for a vehicle equipped with an automatic transmission equipped with a lock-up clutch that improves the starting performance when the power transmission action of the fluid coupling is reduced.

  In the control device according to the second invention, in addition to the structure of the first invention, the control means slips the clutch when the vehicle starts and transmits the power of the power source to the speed change mechanism. Means for controlling the fastening force. The control method according to the sixth invention has the same requirements as the control device according to the second invention.

  According to the second or sixth aspect of the invention, the driving force is transmitted from the power source to the transmission mechanism while slipping (sliding) the clutch (lock-up clutch) of the fluid coupling (torque converter). ) Can be avoided.

  In the control device according to the third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the detecting means detects a decrease in the power transmission action of the fluid coupling based on a change in the operation mode of the power source. Including means. The control method according to the seventh invention has the same requirements as the control device according to the third invention.

  According to the third or seventh invention, when the power transmission action of the fluid coupling is lowered, the load of the power source is lowered. When the power source is an engine and the engine speed is controlled to be constant, the fuel injection amount decreases. When the power source is an engine and the fuel injection amount is controlled to be constant, the engine speed increases. As described above, it is possible to detect a decrease in the power transmission action of the fluid coupling based on the change in the operation mode of the power source.

  In the control device according to the fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the detection means includes means for detecting a decrease in the power transmission action of the fluid coupling based on a change in the load of the power source. Including. The control method according to the eighth invention has the same requirements as the control device according to the fourth invention.

  According to the fourth or eighth aspect of the invention, when the power transmission action of the fluid coupling is reduced, the load of the power source is reduced. Therefore, the reduction in the power transmission action of the fluid coupling can be detected based on the reduction in the load.

  A program according to a ninth invention is a program for realizing the control method according to any of the fifth to eighth inventions by a computer, and the recording medium according to the tenth invention is any one of the fifth to eighth inventions It is the medium which recorded the program which actualizes the control method which relates to invention with the computer.

  According to the ninth or tenth invention, the control method according to any of the fifth to eighth inventions can be realized using a computer (which may be general purpose or dedicated).

  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.

  FIG. 1 illustrates a power train of a vehicle including an ECU that is a control device according to an embodiment of the present invention.

  As shown in FIG. 1, the vehicle includes an engine 100, an automatic transmission 200 (a torque converter 210 and a transmission mechanism 220), an ECU (Electronic Control Unit) 500 that controls these, and a shift position in the ECU 500. It includes a shift position sensor 600 for inputting a signal and a brake switch 700 for inputting an ON signal when the brake is operated. The control device according to the present embodiment is not limited to a vehicle having such a power train. In addition to the components of the power train, a motor (motor generator) that assists the engine may be included. Further, it may be a power train that does not have an engine and has only a motor (motor generator) as a power source. That is, the power source is not limited to the engine that is most commonly used in vehicles. The transmission mechanism may be a stepped type or a stepless type.

  In the following, a case will be described in which the control device according to the embodiment of the present invention is applied to a power train including automatic transmission 200 having engine 100, torque converter 210, and transmission mechanism 220 shown in FIG. To do.

  ECU 500 outputs a control signal such as a throttle opening command signal to engine 100 and receives a detection signal such as an engine speed signal.

  ECU 500 also outputs a control signal that commands engagement or release (including slip) of the lockup clutch of torque converter 210. Further, ECU 500 outputs a control signal that is a hydraulic pressure command signal to transmission 220, or receives a detection signal such as an output shaft rotation speed signal from transmission mechanism 220.

  As described above, the automatic transmission 200 includes a torque converter 210 that is a fluid coupling, (1) a gear-type stepped transmission mechanism that is a transmission mechanism, (2) a belt-type continuously variable transmission mechanism, and (3) traction. One of continuously variable transmission mechanisms.

  The torque converter 210, which is a fluid coupling, includes a lockup clutch. The lock-up clutch mechanically directly connects a drive side member (pump impeller on the engine 100 side) and a driven side member (turbine runner on the transmission mechanism 220 side) of the torque converter 210. A lockup region in which such a lockup clutch is engaged is normally set based on, for example, the vehicle speed and the throttle opening.

  The rotational speed of engine 100 is NE (engine rotational speed), the output shaft rotational speed of torque converter 210 is NT (turbine rotational speed), and the output shaft rotational speed of automatic transmission 200 is NOUT (output rotational speed). Further, the gear ratio of the speed change mechanism 220 is turbine rotational speed NT / output shaft rotational speed NOUT.

  The torque converter 210 will be described with reference to FIG. The present invention can be applied to all fluid couplings.

  As shown in FIG. 2, the torque converter 210 is opposed to the pump impeller 106 in an internal space surrounded by the front cover 102 on the engine 100 side and the pump cover 104 fixed to the front cover 102 by a welded portion 300. A turbine runner 108, a stator 110 between the pump impeller 106 and the turbine runner 108, and a lock-up clutch 114 facing the end wall of the front cover 102 are provided. The stator 110 is positioned in the axial direction by a first thrust bearing interposed between the pump impeller 106 and a second thrust bearing interposed between the turbine runner 108. The turbine runner 108 is positioned in the axial direction by a thrust bearing interposed between the turbine runner 108 and the turbine runner 108, which meets the turbine hub 118 and is connected to the rotating shaft.

  The lockup clutch 114 is connected to the turbine runner 108 so that when the lockup clutch 114 is frictionally engaged, power is transmitted from the pump impeller 106 to the turbine runner 108 via the lockup clutch 114. It is configured. Further, the stator 110 is instructed by the one-way clutch 112 and has a structure that rotates only in one direction.

  In the present embodiment, a hydraulic control circuit that controls the hydraulic oil circulation system in the fluid portion (pump impeller 106, turbine runner 108, stator 110, etc.) of torque converter 210 and the engagement pressure of lockup clutch 114. It is separated from the circulation system. That is, due to the temperature of the hydraulic oil of the automatic transmission 200 being low, the circulation amount of the hydraulic oil inside the fluid portion of the torque converter 210 is reduced or bubbles are mixed in the hydraulic oil, and the power of the torque converter 210 is reduced. The transmission effect is reduced. However, the hydraulic fluid circulation system of the fluid portion (pump impeller 106, turbine runner 108, stator 110) of the torque converter 210 shown in FIG. 2 and the circulation system of the hydraulic control circuit of the lockup clutch 114 are separated separately. Therefore, even when the power transmission action of the torque converter 210 is lowered, the hydraulic control of the engagement pressure of the lockup clutch 114 can be normally executed. Have FIG. 2 is only an example of a torque converter having such an action.

  The control device according to the present embodiment includes a CPU (Central Processing Unit) included in ECU 500, a memory, and a program that is read from the memory and executed by the CPU, even in hardware mainly composed of digital circuits and analog circuits. It can also be realized with software based on the above. In general, it is said that it is advantageous in terms of operation speed when realized by hardware, and advantageous in terms of design change when realized by software. Below, the case where a control apparatus is implement | achieved as software is demonstrated.

  With reference to FIG. 3, a control structure of a program executed by ECU 500 as the control device according to the present embodiment will be described. Note that this program is repeatedly executed at a predetermined cycle time.

  In step (hereinafter step is abbreviated as S) 100, ECU 500 detects the shift position operated by the driver. At this time, ECU 500 detects the current shift position of automatic transmission 200 based on the signal input from shift position sensor 600. In S200, ECU 500 detects the state of brake switch 700 indicating that the brake pedal is being operated by the driver. It is assumed that the brake is operating when the brake switch 700 is on. Further, it may be determined whether the brake is operating based on the brake master cylinder pressure. In S300, ECU 500 detects output shaft rotation speed NOUT of automatic transmission 200.

  In S400, ECU 500 determines whether the shift position is a forward travel position (D position) or a reverse travel position (R position). If the shift position is the D position or the R position (YES in S400), the process proceeds to S500. Otherwise (NO in S400), this process ends.

  In S500, ECU 500 determines whether or not the vehicle is in a stopped state. At this time, ECU 500 determines that the vehicle is in a stopped state, for example, when output shaft rotation speed NOUT of the automatic transmission is equal to or less than a threshold value close to 0 and the brake switch is on. If the vehicle is in a stopped state (YES in S500), the process proceeds to S600. Otherwise (NO in S500), this process ends.

  In S600, ECU 500 detects engine speed NE of engine 100. In S700, ECU 500 detects the fuel injection amount in engine 500. In S800, ECU 500 determines whether or not the load of engine 100 is smaller than a threshold value. If the load on engine 100 is smaller than the threshold value (YES in S800), the process proceeds to S900. If not (NO in S800), the process proceeds to S1000.

  Here, during the processing of S600 to S800, the vehicle is stopped at the D position or the R position, and the fuel injection is performed so that the engine 100 is in an idle state and the idling speed is maintained by ISC (Idle Speed Control). The amount (ISC injection amount) is controlled. In such a case, the pump impeller 106 (pump impeller) of the torque converter 210 rotates and the turbine runner 108 (turbine runner) does not rotate. If the amount of hydraulic fluid in the fluid portion (pump impeller 106, turbine runner 108, stator 110, etc.) of the torque converter 210 is sufficient, the power transmission action of the torque converter 210 is not reduced. However, if the amount of hydraulic fluid in the fluid portion (pump impeller 106, turbine runner 108, stator 110, etc.) of the torque converter 210 is not sufficient, the power transmission action of the torque converter 210 is reduced (lost drive phenomenon). . For this reason, when the power transmission action of torque converter 210 decreases, the load on engine 100 decreases. That is, the output torque of engine 100 is reduced and the fuel injection amount is reduced as compared with the case where the lost drive phenomenon has not been reached. For this reason, the threshold value in S800 is set to a value corresponding to a decrease in engine load when such a lost drive occurs. Since this is done, this reduction in engine load can be determined by the change in the fuel injection amount (ISC injection amount).

  In S900, ECU 500 determines that the power transmission action of torque converter 210 is reduced (the driving force of the vehicle is reduced). Thereafter, the process proceeds to S1100.

  In S1000, ECU 500 determines that the power transmission action of torque converter 210 is not reduced and the desired action is maintained (the driving force of the vehicle is not reduced and the desired drive is maintained). to decide. Thereafter, the process proceeds to S1300.

  In S1100, ECU 500 determines whether or not a request for starting the vehicle has been detected. A request to start the vehicle is detected when the driver releases the brake pedal or steps on the accelerator pedal. In S1200, ECU 500 performs slip control on lock-up clutch 114, and ensures the driving force at the time of start-up by lock-up clutch 114. Thereafter, this process ends.

  In S1300, ECU 500 determines whether or not a request for starting the vehicle has been detected. In S1400, ECU 500 controls to release lock-up clutch 114, and secures the driving force at the start by torque converter 210 instead of lock-up clutch 114. Thereafter, this process ends.

  The operation of the vehicle controlled by ECU 500 serving as the control device according to the present embodiment based on the structure and flowchart as described above will be described. In the following, the operation when the vehicle starts from a state where the vehicle is stopped at the D position or the R position will be described.

[When power transmission action of automatic transmission 200 is reduced]
The shift position is detected (S100), the state of the brake switch is detected (S200), and the output shaft rotational speed NOUT of the automatic transmission 200 is detected (S300).

  Since the driver has depressed the brake pedal at the D position or the R position and the vehicle has stopped (YES at S400, YES at S500), the rotational speed of engine 100 is detected. At this time, the engine 100 is in an idling state. Therefore, the fuel injection amount (ISC injection amount) is injected by engine 100 by ISC.

  The fluid of the torque converter 210 (pump impeller 106, turbine runner 108, stator, etc.) due to the fact that the hydraulic oil of the automatic transmission 210 is low in temperature, high in viscosity, low in oil pan level, and the turbine runner 108 is not rotating. 110) or the like is not sufficiently lubricated, or bubbles are contained in the hydraulic oil. Therefore, the power transmission action of torque converter 210 is reduced, and the load on engine 100 is reduced (YES in S800).

  In such a state, even when the power of engine 100 is transmitted to transmission mechanism 220 only by torque converter 210 when the vehicle starts, the driving force is insufficient. Therefore, when a vehicle start request is detected (YES in S1100), lock-up clutch 114 of torque converter 210 is slip-controlled (the engine 100 is stalled so as not to be in a fully engaged state as a partially engaged state). The vehicle is started (S1200). Even in this case, the hydraulic fluid circulation system of the fluid part (pump impeller 106, turbine runner 108, stator 110) of the torque converter 210 and the hydraulic system of the lockup clutch 114 are separated separately. Therefore, even when the power transmission action of the torque converter 210 is reduced, the control of the engagement pressure of the lockup clutch 114 can be executed normally.

  For this reason, even if the power transmission action of the torque converter 210 is reduced due to a small amount of hydraulic oil or air bubbles in the fluid part (pump impeller 106, turbine runner 108, stator 110, etc.) of the torque converter 210, Even if the driving force of the torque converter is reduced when the hydraulic oil of the automatic transmission 200 is at a low temperature, the driving force of the engine 100 can be transmitted to the transmission mechanism 220 by the lockup clutch 114. A good starting characteristic can be realized.

[When the power transmission action of the automatic transmission 200 is not reduced]
If the hydraulic oil of the automatic transmission 210 is not low in temperature, the viscosity is low and the oil pan level is not lowered. Therefore, the fluid part (pump impeller 106, Turbine runner 108, stator 110, etc.) are sufficiently lubricated, and the oil does not contain bubbles. For this reason, the power transmission effect of torque converter 210 has not decreased, and therefore load of engine 100 has not decreased (NO in S800).

  In such a state, even when the power of the engine 100 is transmitted to the speed change mechanism 220 only by the torque converter 210 when the vehicle starts, the driving force is not insufficient. Therefore, when a vehicle start request is detected (YES in S1300), lockup clutch 114 of torque converter 210 is in a released state, and torque converter 210 transmits the driving force of engine 100 to transmission mechanism 220, causing the vehicle to The vehicle is started (S1400).

  Therefore, when the power transmission action of the torque converter 210 is not reduced, the driving force of the engine 100 can be transmitted to the speed change mechanism 220 without using the lockup clutch 114, and the vehicle has a good start characteristic. Can be realized.

  Note that the reduction in the power transmission effect of the torque converter 210 may be calculated based on the temperature of the hydraulic oil of the automatic transmission 200 and the vehicle stop time. For example, it is determined that the power transmission action of the torque converter 210 is likely to decrease even when the vehicle stop time is short as the temperature of the hydraulic oil is low. It is determined that the power transmission action is unlikely to decrease. When the temperature of the hydraulic oil is lower than the first temperature, if the vehicle stop time exceeds the first set time, it is determined that the power transmission action has been reduced, and the vehicle has a higher hydraulic oil temperature than the first temperature. When the stop time exceeds the time set for the first set time, it can be determined that the power transmission action has decreased.

  Further, a decrease in the power transmission function of torque converter 210 may be determined based on a change in engine speed NE as shown below.

  It is assumed that the vehicle is stopped at the D position or the R position, the engine 100 is in an idle state, and the fuel injection amount (ISC injection amount) is controlled to be constant by ISC (Idle Speed Control). In such a case, if the amount of hydraulic fluid in the fluid portion (pump impeller 106, turbine runner 108, stator 110, etc.) of the torque converter 210 is not sufficient, the power transmission action of the torque converter 210 is reduced (lost drive phenomenon). ) Occurs. For this reason, when the power transmission action of torque converter 210 decreases, the load on engine 100 decreases. That is, the rotational speed NE of the engine 100 increases as compared to the case where the lost drive phenomenon has not been reached (because the fuel injection amount is constant and the load on the engine 100 decreases). Therefore, the threshold value in S800 is set to a value corresponding to an increase in the rotational speed of engine 100 when such a lost drive occurs. Since this is done, this reduction in engine load can be determined by a change in the rotational speed NE of the engine 100.

  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 containing ECU which is a control apparatus of the automatic transmission which concerns on this Embodiment. It is sectional drawing of a torque converter. It is a flowchart which shows the control structure of the program performed by ECU.

Explanation of symbols

  100 engine, 200 automatic transmission, 210 torque converter, 220 transmission mechanism, 500 ECU, 600 shift position sensor, 700 brake switch.

Claims (10)

A vehicle control device equipped with an automatic transmission connected to a power source,
The automatic transmission includes a fluid coupling connected to the output shaft of a power source, and a transmission mechanism connected to the output shaft of the fluid coupling,
The fluid coupling includes a clutch that mechanically connects the input and output shafts,
The controller is
Detecting means for detecting a decrease in power transmission action of the fluid coupling;
And a control means for controlling the fastening force of the clutch so that the power of the power source is transmitted to the speed change mechanism using the clutch when the vehicle starts off when the reduction of the power transmission action is detected. ,Control device.   The said control means is a means for controlling the fastening force of the said clutch so that the said clutch may be slip-controlled at the time of start of a vehicle, and the motive power of a power source may be transmitted to a transmission mechanism. Control device.   The control device according to claim 1, wherein the detection unit includes a unit for detecting a decrease in power transmission action of the fluid coupling based on a change in an operation mode of the power source.   The control device according to claim 3, wherein the detection means includes means for detecting a decrease in power transmission action of the fluid coupling based on a change in load of the power source. A method for controlling a vehicle equipped with an automatic transmission connected to a power source,
The automatic transmission includes a fluid coupling connected to the output shaft of a power source, and a transmission mechanism connected to the output shaft of the fluid coupling,
The fluid coupling includes a clutch that mechanically connects the input and output shafts,
The control method is:
A detection step of detecting a decrease in power transmission action of the fluid coupling;
And a control step for controlling the fastening force of the clutch so that the power of the power source is transmitted to the speed change mechanism using the clutch when the vehicle starts. Method.   The control method according to claim 5, wherein the control step includes a step of controlling a fastening force of the clutch so that the clutch is slip-controlled when the vehicle starts and a power of a power source is transmitted to the speed change mechanism. .   The control method according to claim 5, wherein the detecting step includes a step of detecting a decrease in power transmission action of the fluid coupling based on a change in an operation mode of the power source.   The control method according to claim 7, wherein the detecting step includes a step of detecting a decrease in power transmission action of the fluid coupling based on a change in a load of the power source.   The program which makes a computer implement | achieve the control method in any one of Claims 5-8.   A recording medium recording a program for causing a computer to implement the control method according to claim 5.

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