JP2008121591A - Control device and control method for vehicle mounting automatic transmission, program materializing control method and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compatibly materialize improvement of fuel economy and avoidance of shift shock in a vehicle mounting an automatic transmission including a torque converter provided with a lock up clutch. <P>SOLUTION: EUC executes a program including a step S130 detecting quantity of state of a vehicle relating to a fuel cut condition if it is judged that accelerator-off up-shift is started (Yes in S120) by detecting vehicle speed V and accelerator opening, and a step not executing fuel cut when the lock up clutch is under an engagement state (including a slip state) (Yes in S160) even if a fuel cut condition is satisfied (Yes in S140) but executing fuel cut when the lock up clutch is under a disengagement state (No in S160). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to control of a vehicle that is equipped with an automatic transmission and executes fuel cut control based on the running state of the vehicle, and in particular, determines whether or not to execute fuel cut control during a shift according to the state of a lockup clutch. The present invention relates to control for improving fuel efficiency and reducing shift shock.

  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 throttle opening (accelerator opening) of the engine and the vehicle speed, and automatically switches the transmission gear stage. More specifically, a plurality of friction engagement elements (clutch and brake in the speed change mechanism) are controlled to either the engaged state or the released state by hydraulic pressure, and the power transmission path is switched.

  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). For example, an upshift shift line and a downshift shift line are set using the vehicle speed and the throttle opening as parameters, and an upshift shift or a downshift shift occurs when the shift line is crossed based on the vehicle speed and the throttle opening. Is executed.

  The torque converter is also called a fluid coupling, and the power of 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 inside. 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.

  By the way, for example, when the vehicle is decelerated, the engine output (in the following, the engine output may be used synonymously with the engine torque) is not required, so the deceleration state, the engine speed, the engine coolant temperature, etc. In accordance with the operating state, so-called fuel cut control is executed to stop the fuel supply to the engine in the deceleration state, thereby improving the fuel consumption by reducing the fuel consumption. This fuel cut control is a control that improves fuel efficiency by reducing the supply of fuel to the engine as much as possible within a range that does not impair driving performance and riding comfort. In general, the supply of fuel is stopped when the engine speed falls within a predetermined range (more than the fuel cut speed) during deceleration while the engine is idling. Specifically, if the throttle valve is closed during traveling (decelerated traveling) and the engine speed is equal to or higher than the fuel cut speed, the fuel supply is stopped. Further, when the engine speed decreases and reaches the return speed (fuel cut return speed) that defines the lower limit of the range, the fuel supply is resumed to prevent engine stall.

  In recent years, in order to prolong the fuel cut control, the lockup clutch described above is engaged (directly connected) or slipped (the pump speed on the input side (corresponding to the engine speed)) and the turbine on the output side. The engagement force (engagement pressure) of the lockup clutch is set to a predetermined state according to the rotational difference from the rotational speed (half-engaged state), and the reduction of the engine rotational speed is delayed to further improve the fuel efficiency. Improvements may be made. As described above, since the slip state is a half-engaged state, the description will be made including the engaged state.

  Japanese Patent No. 2601000 (Japanese Patent Laid-Open No. 4-112936, Patent Document 1) is a general control device for an engine and an automatic transmission that executes fuel cut control at the time of deceleration. Disclosed is a comprehensive control device for preventing variation in shift shock due to the above. This integrated control device is equipped with an engine equipped with a fuel cut control unit that starts fuel cut including the condition that the vehicle speed is equal to or higher than a reference value when the accelerator is released, and in response to an increase in vehicle speed and a decrease in accelerator opening. And a shift control unit that shifts based on a shift schedule having an upshift shift line set to upshift, an accelerator operation detection unit that detects an accelerator operation, and a vehicle speed Even if the vehicle speed is above the reference value when the accelerator is lifted and operated, the shift speed is determined by the upshift line on the shift schedule and a shift command is issued. A general control unit that prohibits the start of fuel cut control.

When the accelerator is released during driving and the vehicle speed is detected to be higher than the reference value, the fuel cut control is performed on the condition that the upshift command is not generated in the shift control unit. The fuel efficiency will be improved. On the other hand, even when the accelerator is released during driving and the vehicle speed is detected to be higher than the reference value, an upshift command is issued by the upshift line on the shift schedule. Is prohibited from starting the fuel cut control. Therefore, when the fuel cut control and the upshift transmission control are performed independently, when the accelerator is released in the vehicle speed range around the reference value and the upshift is performed due to a decrease in the accelerator opening, the vehicle speed If the vehicle speed is less than the reference value, the fuel cut is performed. If the vehicle speed is less than the reference value, the fuel cut is not executed, and the upshift shift shock varies depending on the presence or absence of the fuel cut. According to this integrated control device, according to the integrated control device disclosed in Patent Document 1, when an accelerator shift-off operation is performed, even if the vehicle speed is equal to or higher than the reference vehicle speed, if an upshift gear shift command is issued, the fuel is uniformly supplied. The start of cutting is prohibited. As a result, it is possible to prevent the upshift gear shift shock from occurring due to the presence or absence of the fuel cut.
Japanese Patent No. 2601000 (Japanese Patent Laid-Open No. 4-112936)

  When the fuel cut control and the shift control are performed independently, an upshift is performed due to a decrease in the accelerator opening when the accelerator is released and operated in the vehicle speed range around the reference value. At this time, if the vehicle speed is equal to or higher than the reference value, the fuel is cut, and if the vehicle speed is less than the reference value, the fuel cut is not executed, and the upshift shift shock varies depending on the presence or absence of the fuel cut. In Patent Document 1 described above, when the upshift is performed, the fuel cut control is uniformly prohibited regardless of the vehicle speed.

  However, from the viewpoint of improving fuel efficiency, it is preferable to execute fuel cut control as much as possible. On the other hand, if fuel cut control is uniformly executed even during upshifts with an emphasis on improving fuel efficiency, a shift shock may occur depending on the state of the lockup clutch that is not mentioned in Patent Document 1. . When the lockup clutch is engaged, the change in the engine speed (torque converter input shaft speed) directly changes the input shaft speed of the transmission mechanism (output shaft speed of the torque converter). Because.

  However, Patent Document 1 does not mention fuel cut control during upshifting according to the state of the lockup clutch.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to control a vehicle equipped with an automatic transmission equipped with a lock-up clutch that achieves both improvement in fuel consumption and avoidance of shift shock. An apparatus, a control method, a program for realizing the control method, and a recording medium are provided.

  A control device according to a first aspect of the invention controls a vehicle equipped with an internal combustion engine that executes fuel cut control and a stepped automatic transmission. The automatic transmission includes a fluid coupling connected to the output shaft of the internal combustion engine and a speed change mechanism connected to the output shaft of the fluid coupling. The fluid coupling includes a lock-up clutch that mechanically connects the input and output shafts. Prepare. The control device includes: a fuel cut execution means for controlling the internal combustion engine so as to execute a fuel cut that stops fuel supply to the internal combustion engine when the vehicle state satisfies a predetermined execution condition; In order to determine whether or not to permit execution of fuel cut by the fuel cut execution means based on the state of the lockup clutch within the shift period of the automatic transmission and the detection means for detecting the clutch state Determination means. The control method according to the fourth invention has the same requirements as the control device according to the first invention.

  According to the first or fourth invention, when the fuel cut is executed while the lockup clutch is engaged, the sudden decrease in the rotational speed of the internal combustion engine is mechanically connected to the transmission mechanism by the lockup clutch. Directly communicated. For this reason, when the lockup clutch is engaged (directly coupled and slipped), the input shaft rotational speed of the transmission mechanism changes in the same manner as a sudden decrease in the engine rotational speed. In such a case, for example, when an upshift is performed, the friction engagement element of the speed change mechanism is engaged or released in a state where the rotation speed is changing rapidly. For this reason, a shift shock occurs. For this reason, execution of fuel cut during the (upshift) shift period is determined based on the state of the lockup clutch. For example, when the lockup clutch is engaged (directly connected state or slip state), the fuel cut is prohibited and the fuel supply to the internal combustion engine is continued to stop the fuel supply. To avoid a rapid decrease in the input shaft speed of the speed change mechanism. For this reason, a shift shock can be prevented. On the other hand, when the lock-up clutch is not engaged (in the released state), fuel cut is executed, and the lock is applied even if the rotational speed of the internal combustion engine suddenly decreases by stopping the fuel supply to the internal combustion engine. Since the up clutch is in a non-engaged state (a released state in which the lock-up clutch is neither directly connected nor slipped), the speed of the input shaft of the speed change mechanism does not rapidly decrease. For this reason, fuel cut can be improved because the fuel is cut even during the upshift. 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 achieves both improvement in fuel efficiency and avoidance of shift shock.

  In the control device according to the second invention, in addition to the configuration of the first invention, the determining means is in an engaged state in which the lockup clutch includes a slip state during the upshift speed period of the automatic transmission. And means for not permitting execution of fuel cut. The control method according to the fifth invention has the same requirements as those of the control device according to the second invention.

  According to the second or fifth invention, when the lockup clutch is engaged (this engagement includes both when the lockup clutch is in the direct connection state and when it is in the slip state). ) The fuel cut is prohibited, the fuel supply to the internal combustion engine is continued, the rapid decrease in the rotational speed of the internal combustion engine due to the stop of the fuel supply is avoided, and the rapid decrease in the input shaft rotational speed of the transmission mechanism is avoided. For this reason, a shift shock can be prevented.

  In the control device according to the third aspect of the invention, in addition to the configuration of the first aspect of the invention, the determination means determines that the fuel is released when the lockup clutch is in the disengaged state during the upshifting period of the automatic transmission. Including means for permitting execution of the cut. The control method according to the sixth invention has the same requirements as those of the control device according to the third invention.

  According to the third or sixth aspect of the invention, when the lockup clutch is not engaged (when this is not engaged, the lockup clutch is in the released state), fuel cut is executed, and the internal combustion engine Even if the rotational speed of the internal combustion engine suddenly decreases due to the stop of fuel supply to the engine, the lockup clutch is not engaged, and therefore the input shaft rotational speed of the transmission mechanism does not rapidly decrease. For this reason, fuel cut can be improved because the fuel is cut even during the upshift.

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

  According to the seventh or eighth invention, the vehicle control method according to any one of the fourth to sixth inventions can be realized by 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 (Electronic Control Unit) that is a control device according to an embodiment of the present invention.

  As shown in FIG. 1, engine 100, automatic transmission 200 (torque converter 210 and transmission mechanism 220), ECU 500 for controlling these, and a signal indicating the opening of the accelerator pedal are input to ECU 500. And an accelerator opening sensor 600. 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. However, the control according to the present embodiment is such that fuel cut control is executed during deceleration traveling of engine 100, the speed change mechanism is a stepped type, and torque converter 210 includes a lock-up clutch. It is a premise of the power train to which the device is applied.

  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. Yes (no motor). Furthermore, the lock-up clutch is in the engaged state, where the lock-up clutch is in the slip state (the state that is connected while being (slightly) slipped) and the engagement state (the direct connection state), and the lock-up clutch is not engaged The state will be described assuming that the lockup clutch is in a released state.

  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 disengagement of the lockup clutch of torque converter 210. Further, ECU 500 outputs a control signal that is a hydraulic pressure command signal to transmission mechanism 220, or receives a detection signal such as an output shaft rotation number signal from transmission mechanism 220.

  As described above, the automatic transmission 200 includes the torque converter 210 that is a fluid coupling and the gear-type stepped transmission mechanism that includes a plurality of friction engagement elements that is a transmission mechanism.

  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 also 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 via a damper spring 116, and when the internal pressure of the back pressure chamber formed between the lockup clutch 114 and the front cover 102 is reduced, the torque converter 210. The lockup clutch 114 is frictionally engaged with the front cover 102 by the internal pressure of the internal gap, and power is transmitted from the front cover 102 to the turbine runner 108 via the lockup clutch 114. 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, lock-up clutch 114 of torque converter 210 is controlled to either an engaged state (including a slip state) or a non-engaged state by hydraulic pressure from a hydraulic control circuit controlled by ECU 500. Is done.

  With reference to FIG. 3, a functional block diagram of the control device according to the present embodiment will be described. In the functional block diagram shown in FIG. 3, the same components as those shown in FIG. Their functions are the same. Therefore, detailed description thereof will not be repeated here.

  The control device in the functional block shown in FIG. 3 is read out from a CPU (Central Processing Unit) and a memory included in the ECU 500 and executed by the CPU even in hardware mainly composed of a digital circuit or an analog circuit. It can also be realized by software mainly composed of programs. 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. Note that a recording medium on which such a program is recorded is also an embodiment of the present invention.

  As shown in FIG. 3, this control device performs shift control based on the vehicle speed, throttle opening, and shift map (upshift shift line and downshift shift line), and also applies the engagement pressure of the lockup clutch 114. A shift control unit / lockup clutch control unit 510 to be controlled, a lockup determination unit 520 for determining an engagement state of the lockup clutch 114 (particularly, determining that the lockup clutch 114 is engaged), an accelerator Upshift start determination unit 530 that determines the start of an upshift when the upshift shift line is crossed by reducing the pedal opening (including accelerator off), (1) state of lockup clutch 114, (2) upshift Based on the state of the shift start and (3) the state of the engine 100 such as the engine speed, And a central control unit 540 determines whether or not to execute the Erukatto.

  Detection signals are input to the shift control unit / lock-up clutch control unit 510 from the vehicle speed detection unit 610 and the accelerator opening detection unit. The shift control unit / lockup clutch control unit 510 stores a shift map (upshift shift line and downshift shift line) using the vehicle speed and the throttle opening (accelerator opening) as parameters.

  The integrated control unit 540 receives a determination signal from the lockup determination unit 420 and the upshift start determination unit 530 and a detection signal from the accelerator opening detection unit 600 and the engine speed detection unit 620. When the integrated control unit 540 determines that the fuel cut is to be performed, the fuel cut control is performed on the engine 100 by the fuel cut control unit 550. In FIG. 3, a portion corresponding to ECU 500 in FIG. 1 is surrounded by an alternate long and short dash line.

  With reference to FIG. 4, a control structure of a program executed by ECU 500 that is the control device according to the present embodiment will be described. Note that this program is repeatedly executed at a predetermined cycle time. Further, this program is limited to the fuel cut control during upshifting with the accelerator off, and generally the fuel cut is controlled by another program.

  In step (hereinafter step is abbreviated as S) 100, ECU 500 detects vehicle speed V. At this time, ECU 500 detects vehicle speed V by multiplying output shaft speed NOUT of automatic transmission 200 by the final gear ratio. The vehicle speed V may be detected based on the vehicle speed signal from the vehicle speed sensor.

  In S110, ECU 500 detects the accelerator opening. In S120, ECU 500 determines whether or not an accelerator-off upshift is started. At this time, the determination is made based on the throttle opening (accelerator opening), the vehicle speed V, and the upshift shift line of the stored shift map. If it is determined that the accelerator-off upshift is started (YES in S120), the process proceeds to S130. If not (NO in S120), the process returns to S100.

  In S130, ECU 500 detects a vehicle state quantity (the number of revolutions of engine 100, the coolant temperature of engine 100, etc.) relating to the fuel cut condition for starting the fuel cut. In S140, ECU 500 determines whether or not a fuel cut condition is satisfied. If the fuel cut condition is satisfied (YES in S140), the process proceeds to S150. If not (NO in S140), the process proceeds to S180.

  In S150, ECU 500 detects the engagement state of lockup clutch 114. At this time, since ECU 500 cannot actually sense the engagement state (engagement pressure) of lockup clutch 114, ECU 500 detects a control signal output from ECU 500 to the hydraulic control unit of lockup clutch 114.

  In S160, ECU 500 determines whether or not lockup clutch 114 is in an engaged state. It is determined whether or not the lock-up clutch 114 is in an engaged state based on whether or not the control signal output from the ECU 500 to the hydraulic pressure control unit of the lock-up clutch 114 is a signal indicating the engaged state. If lock-up clutch 114 is engaged (YES at S160), the process proceeds to S180. If not (NO in S160), the process proceeds to S170.

  In S170, ECU 500 executes fuel cut and stops fuel supply in engine 100 (stops fuel injection from the injector). Thereafter, the process proceeds to S190. In S180, ECU 500 does not perform fuel cut and continues fuel supply in engine 100 (injects fuel from the injector).

  In S190, ECU 500 determines whether or not the upshift has been completed. At this time, ECU 500 determines whether the turbine rotational speed (also the input shaft rotational speed of transmission mechanism 220), which is the output shaft rotational speed of torque converter 210, has reached the synchronous rotational speed of the gear stage after the upshift. Thus, it is determined whether or not the upshift is completed. Further, it may be determined whether or not the upshift has been completed based on the elapsed time from the start of the shift (YES in S130).

  In S200, as in S130, ECU 500 detects a vehicle state quantity (such as the number of revolutions of engine 100, the coolant temperature of engine 100, etc.) relating to the fuel cut condition for starting fuel cut. In S210, ECU 500 determines whether or not the fuel cut condition is satisfied, similarly to S140. If the fuel cut condition is satisfied (YES in S210), the process proceeds to S220. If not (NO in S210), the process proceeds to S230.

  In S220, ECU 500 performs fuel cut and stops fuel supply in engine 100 (stops fuel injection from the injector). Thereafter, this process ends. In S230, ECU 500 continues fuel supply in engine 100 without performing fuel cut (injects fuel from the injector).

  The operation of the vehicle controlled by ECU 500 serving as the control device according to the present embodiment based on the above-described structure and flowchart will be described with reference to FIG.

[Lock-up clutch engaged]
While the vehicle is traveling, the vehicle speed V is detected (S100), and the accelerator opening is detected (S110). For example, when the vehicle speed is in the vicinity of the upshift shift line and the driver removes his or her foot from the accelerator pedal and the accelerator is off, the upshift shift line with the accelerator off is started by crossing the upshift shift line in the shift map. (YES in S120).

  Further, when the vehicle state quantity related to the fuel cut condition for starting the fuel cut is detected (S130) and the fuel cut condition is satisfied (YES in S140), the engagement state of the lockup clutch 114 is detected.

  If lock-up clutch 114 is in an engaged state (including a slip state) (YES in S160), fuel cut is not executed (S180). Since the lock-up clutch 114 is in an engaged state (the pump impeller 106 and the turbine runner 108 are mechanically directly connected (directly connected) or slightly slipped), the engine The rotational speed NE and the turbine rotational speed NT that is the input shaft rotational speed of the speed change mechanism 220 are the same (substantially the same).

  As shown in FIG. 5, fuel cut is not executed at time T (1), and a rapid decrease in the rotational speed of engine 100 is avoided. The solid line from time T (1) to time T (3) in FIG. As shown, the rotational speed decreases slowly. The upshift is executed in a state where the turbine rotational speed is not rapidly decreasing, and the rotational speed is not rapidly changing (decreasing) (from time T (1) to time T ( Since the friction engagement element is engaged in the state indicated by the solid line 3), the shift shock does not increase.

  On the other hand, as shown by the dotted line in FIG. 5, if fuel cut is executed while the lockup clutch 114 is engaged (slip), the engine speed of the engine 100 rapidly decreases due to the stop of fuel supply. Then, it is directly transmitted to the turbine runner 108 by the lock-up clutch 114. For this reason, the turbine rotational speed, which is the rotational speed of the input shaft to the transmission mechanism 220, rapidly decreases. In this state, an upshift is executed, and the rotational speed is rapidly changing (decreasing) (a state indicated by a dotted line from time T (1) to time T (2) in FIG. 5). Since the frictional engagement element is engaged, the shift shock is increased and the shift feeling is deteriorated.

[Lock-up clutch not engaged]
When it is determined that an accelerator-off upshift shift is started during travel of the vehicle (YES in S120) and the fuel cut condition is satisfied (YES in S140), lockup clutch 114 Is in the disengaged state (released state) (NO in S160), fuel cut is executed (S170).

  Even if the fuel cut is executed, the sudden decrease in the rotational speed of the engine 100 due to the stop of fuel supply means that the lock-up clutch 114 is not engaged (is not in an engaged state, nor in a slip state in which it is connected while sliding slightly). Therefore, it is only transmitted to the turbine runner 108 by the fluid of the torque converter 210. For this reason, turbine rotation speed does not fall rapidly. In this state, even if an upshift is executed, the frictional engagement element is engaged in a state where the rotational speed has not suddenly changed (decreased), so the shift shock does not increase.

  In this way, during the upshift, when the lockup clutch 114 is disengaged to improve fuel efficiency, the fuel is cut, and when the lockup clutch 114 is engaged to improve the shift feeling. Do not cut fuel.

  As described above, according to the control device according to the present embodiment, during the upshift, when the lockup clutch is engaged, the fuel cut is prohibited and the fuel supply to the engine is continued. A sudden decrease in the engine speed due to the supply stop is avoided to avoid a rapid decrease in the turbine speed. For this reason, a shift shock can be prevented.

  On the other hand, at the time of upshifting, when the lockup clutch is not engaged, a fuel cut is executed, and the lockup clutch is not engaged even if the engine speed drops rapidly due to the stop of fuel supply to the engine. Since it is in a state, it does not cause a rapid decrease in the turbine speed. For this reason, since fuel cut is performed even at the time of upshift, the fuel consumption can be improved.

  In the above-described embodiment, whether or not fuel cut during upshift is determined based on the state of the lockup clutch, but whether or not fuel cut during downshift is changed to the state of the lockup clutch. It does not represent that the aspect determined based on the contact is excluded.

  In the above-described embodiment, the engagement state is determined based on the control signal output to the hydraulic pressure control unit. However, the engagement state of the lockup clutch is determined from the engine speed NE and the turbine speed NT. You may judge.

  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 device of vehicles concerning this embodiment. It is sectional drawing of a torque converter. It is a functional block diagram of the control device of the vehicle concerning an embodiment of the invention. It is a flowchart which shows the control structure of the program performed by ECU. It is a timing chart which shows operation of vehicles controlled by ECU.

Explanation of symbols

  100 engine, 200 automatic transmission, 210 torque converter, 220 transmission mechanism, 500 ECU, 600 accelerator opening sensor.

Claims (8)

A vehicle control device equipped with an internal combustion engine that executes fuel cut control and a stepped automatic transmission,
The automatic transmission includes a fluid coupling connected to the output shaft of the internal combustion engine, and a transmission mechanism connected to the output shaft of the fluid coupling,
The fluid coupling includes a lock-up clutch that mechanically connects the input and output shafts,
The controller is
Fuel cut execution means for controlling the internal combustion engine so as to execute fuel cut to stop fuel supply to the internal combustion engine when the vehicle condition satisfies a predetermined execution condition;
Detecting means for detecting the state of the lock-up clutch;
A control unit including: a determination unit configured to determine whether or not to permit execution of fuel cut by the fuel cut execution unit based on a state of the lockup clutch within a shift period of the automatic transmission; .   The determination unit includes a unit that does not permit execution of the fuel cut when the lockup clutch is in an engaged state including a slip state during an upshift speed change period of the automatic transmission. The control device described.   2. The control according to claim 1, wherein the determination unit includes a unit that permits execution of the fuel cut when the lock-up clutch is in a non-engaged state during an upshift period of the automatic transmission. apparatus. A control method for a vehicle equipped with an internal combustion engine that executes fuel cut control and a stepped automatic transmission,
The automatic transmission includes a fluid coupling connected to the output shaft of the internal combustion engine, and a transmission mechanism connected to the output shaft of the fluid coupling,
The fluid coupling includes a lock-up clutch that mechanically connects the input and output shafts,
The control method is:
A fuel cut execution step for controlling the internal combustion engine so as to execute a fuel cut for stopping fuel supply to the internal combustion engine when a state of the vehicle satisfies a predetermined execution condition;
A detecting step for detecting a state of the lock-up clutch;
And a determination step of determining whether or not to permit execution of fuel cut in the fuel cut execution step based on a state of the lockup clutch within a shift period of the automatic transmission.   The determination step includes a step of not permitting execution of the fuel cut when the lock-up clutch is in an engaged state including a slip state during an upshift speed period of the automatic transmission. The control method described.   5. The control according to claim 4, wherein the determination step includes a step of permitting execution of the fuel cut when the lock-up clutch is in a disengaged state within an upshift speed change period of the automatic transmission. Method.   The program which makes a computer implement | achieve the control method in any one of Claims 4-6.   A recording medium recording a program for causing a computer to implement the control method according to claim 4.

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