JP4640140B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a control device that controls a shift of an automatic transmission mounted on a vehicle.

  An automatic transmission mounted on a vehicle is configured by combining a torque converter to which an output from an engine is input and a transmission gear mechanism that is driven by the output from the torque converter. By selectively engaging and releasing a plurality of frictional engagement elements such as clutches and brakes, the power transmission path of this transmission gear mechanism is switched to a predetermined gear position according to the driver's request and driving state. Shifts automatically. In such an automatic transmission, a friction engagement element for engine braking is provided in addition to a friction engagement element for shifting. The engine brake frictional engagement element normally transmits power only during driving, and is engaged at a predetermined gear stage such as one range or two range, so that the deceleration at those gear stages is achieved. Engage the engine brake when driving.

  In such a shift of an automatic transmission, a so-called clutch-to-clutch shift that shifts by re-engaging the frictional engagement elements that simultaneously perform control for engaging and releasing different frictional engagement elements, A so-called clutch-to-one-way clutch, in which a one-way clutch is arranged on the friction engagement element, and the release-side friction engagement element is released and the engine speed changes to approach the synchronous rotation speed. There is a shift.

  Apart from such a point of view, there is a time when the direction of torque transmitted between the vehicle drive system and the internal combustion engine is reversed, and the driver is caused by torque shock generated in the transmission constituting the vehicle drive system due to this torque reversal. May deteriorate. Moreover, there is a problem that the greater the difference between the rotational speed of the internal combustion engine and the rotational speed of the vehicle drive system at this torque reversal time, the greater the torque shock associated with this torque reversal and the worse the drivability.

  Japanese Patent Laying-Open No. 2004-124857 (Patent Document 1) discloses a throttle opening control device for an internal combustion engine that suppresses such a shock as much as possible and suppresses deterioration of drivability. This control device is an internal combustion engine that gradually changes the throttle opening at a predetermined gradual change speed when changing the throttle opening of the internal combustion engine mounted on the vehicle to a target opening set based on the accelerator opening. An engine throttle opening control device, in which the rotational speed of an engine output shaft that changes as the throttle opening changes changes the direction of torque transmitted between the vehicle drive system and the internal combustion engine. And a speed setting means for reducing the gradual change speed for a predetermined period so as to be small at the time of performing.

According to this control device, the speed of change of the rotational speed of the output shaft of the internal combustion engine is kept small, so that the shock that occurs when the direction of the torque transmitted between the vehicle drive system and the internal combustion engine is reversed is minimized. As a result, deterioration of drivability can be suppressed.
JP 2004-124857 A

  When downshifting is performed with the clutch-to-clutch shift or clutch-to-one-way clutch shift described above, one of the friction engagement elements is released, and then the transmission gear stage after the downshift is performed when the input shaft rotational speed of the automatic transmission is reduced. So that the rotational speed of the internal combustion engine is increased.

  Therefore, as described in Patent Document 1, when a clutch-to-clutch shift or a downshift by a clutch-to-one-way clutch shift is performed when the throttle opening is controlled to reduce the shock. Therefore, since the output of the internal combustion engine is reduced, it takes a relatively long time to increase the rotational speed of the internal combustion engine, and it may be delayed to reach the synchronous rotational speed. The delay in reaching the synchronized rotational speed after the shift eventually lengthens the shift time, and the shift feeling required by the driver cannot be realized.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to perform a downshift in an automatic transmission connected to an output shaft of an internal combustion engine in which output suppression control is executed during acceleration. It is to provide a control device for an automatic transmission that performs well.

  According to a first aspect of the present invention, there is provided a control device for an automatic transmission, wherein output limiting means for limiting the output of a power source when a vehicle shifts to an acceleration state, and whether or not control by the output limiting means is being executed. A detection means for detecting, a shift detection means for detecting whether or not the shift of the automatic transmission is being executed, and when the shift of the automatic transmission is detected to be executed, When it is detected that the control by the determination means for determining whether the stage has shifted to the inertia phase and the output limiting means is being executed, and the determination means determines that the phase has shifted to the inertia phase And a stopping unit for controlling the output limiting unit so as to stop the control by the output limiting unit.

  According to the first invention, for example, in the case of a power-on downshift, it is a time when the vehicle shifts to an acceleration state, so that the output of the power source is limited. On the other hand, in the case of downshifting, torque is not transmitted when the shift phase (phase) transitions from the torque phase to the inertia phase, so the torque direction changes even if the output of the power source is limited or stopped by the output limiting means Acceleration shock does not occur. Therefore, the shift control can be shortened by immediately stopping the limit control by the output limiting means upon entering the inertia phase and increasing the rotational speed of the power source to the synchronous rotational speed after the downshift. Further, since the torque is increased, sufficient acceleration can be realized after the downshift. As a result, it is possible to provide a control device for an automatic transmission that satisfactorily executes a downshift in an automatic transmission connected to an output shaft of an internal combustion engine in which output suppression control is executed during acceleration.

  In the control device according to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the shift detection means includes means for detecting a power-on downshift.

  According to the second invention, since it is a power-on downshift, the output of the power source when shifting from the non-accelerated state to the accelerated state is restricted, and a downshift is performed. If the inertia phase is entered in the downshift, the limit control is stopped, and the speed of the power source can be quickly increased to the synchronous speed after the downshift, thereby shortening the shift time.

  In the control device according to the third invention, in addition to the configuration of the first or second invention, the output limiting means includes means for limiting the opening of the throttle valve of the engine.

  According to the third aspect of the invention, when shifting from the non-accelerated state to the accelerated state, the output of the engine that is the power source can be limited by limiting the opening of the throttle valve.

  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.

A vehicle power train including the control device according to the present embodiment will be described. The control device according to the present embodiment is realized by an ECU (Electronic Control Unit) 1000 shown in FIG. In the present embodiment, the automatic transmission is described as having a planetary gear type reduction mechanism equipped with a torque converter. Further, a vehicle equipped with an engine as a power source for driving the vehicle will be described. However, in the present invention, the prime mover is not limited to the engine, and may be a motor or the like.

  As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, an automatic transmission 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 automatic transmission 300 are connected by a rotating shaft. An output shaft rotational speed NT of the torque converter 200 (turbine rotational speed NT = input shaft rotational speed NIN of the automatic transmission 300) is detected by a turbine rotational speed sensor 410. The output shaft rotational speed NOUT of the automatic transmission 300 is detected by the output shaft rotational speed sensor 420.

  FIG. 2 shows an operation table of the automatic transmission 300. 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. The clutch-to-clutch shift (downshift), which is the object of control according to the present invention, occurs in the case of a downshift from 6th gear to 5th gear in this figure. Similarly, the clutch-to-one-way clutch shift (downshift), which is the object of control according to the present invention, is changed from the 5th speed to the 4th speed, the 4th speed to the 3rd speed, the 3rd speed to the 2nd speed, and the 2nd speed to 1 in this figure. Occurs in the case of downshifts. Hereinafter, a downshift from 6th speed to 5th speed will be exemplified.

  The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100 and an ECT (Electronic Controlled Automatic Transmission) _ECU 1020 that controls the automatic transmission 300.

  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. Further, ECT_ECU 1020 receives from engine ECU 1010 a signal representing engine speed NE detected by engine speed sensor 400 and a signal representing throttle opening detected by the throttle position sensor.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of torque converter 200, the output shaft of torque converter 200, and the output shaft of automatic transmission 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 automatic transmission 300. This is a sensor using a magnetoresistive element.

  A solenoid control signal is output from the ECT_ECU 1020 to the linear solenoid of the automatic transmission 300. The clutch elements (C1 to C4), the brake elements (B1 to B4), and the one-way clutch elements (F0 to F3) shown in FIG. 2 are engaged or released. For example, at the time of downshift from 6th gear to 5th gear, the engagement pressure is controlled so that the clutch C3 is engaged from the disengagement, and the engagement pressure is controlled so that the brake B2 is disengaged from the engagement. Actually, the ECT_ECU 1020 outputs a solenoid control signal to the linear solenoid valve of the hydraulic circuit. The ECT_ECU 1020 calculates a target hydraulic pressure (hydraulic pressure that realizes a target engagement pressure) to be described later, calculates the hydraulic pressure to the hydraulic servo based on the target hydraulic pressure, and outputs the hydraulic pressure to the solenoid valve.

  The hydraulic circuit has, for example, two linear solenoid valves, and switches a transmission path of a planetary gear unit of an automatic transmission to achieve a plurality of friction engagement elements (clutch and clutch) that achieves six forward speeds and one reverse speed. A plurality of hydraulic servos for engaging and releasing the brake). Further, the solenoid modulator pressure is supplied to the input port of the linear solenoid valve, and the control hydraulic pressure from the output port of each linear solenoid valve is supplied to the control oil chamber of the pressure control valve. In the pressure control valve, the line pressure is supplied to each input port, and the pressure regulation from the output port regulated by the control hydraulic pressure is appropriately supplied to each hydraulic servo via the shift valve.

  Such a hydraulic circuit is an example, and actually, a number of hydraulic servos are provided corresponding to the automatic transmission, and a number of shift valves for switching the hydraulic pressure to these hydraulic servos are also provided. The hydraulic servo also has a piston that is oil-tightly fitted to the cylinder by an oil seal, and the piston resists the return spring based on the pressure adjustment hydraulic pressure from the pressure control valve acting on the hydraulic chamber. To contact the outer friction plate and the inner friction material. The friction plate and the friction material are the same for the brake as well as the clutch.

  With reference to FIG. 3, a control structure of a program executed in ECT_ECU 1020 which is the control apparatus according to the present embodiment will be described.

  In step (hereinafter, step is abbreviated as S) 100, ECT_ECU 1020 determines whether or not a clutch-to-clutch downshift (for example, a 6th speed → 5th speed power-on downshift) has been started. This determination is made based on the shift command signal input to the ECT_ECU 1020, or based on the throttle opening of the engine 100 and the vehicle speed based on the automatic shift diagram. When the clutch-to-clutch power-on downshift is started (YES in S100), the process proceeds to S110. Otherwise (NO in S100), this process ends. In the following description, the case where the accelerator pedal is depressed (kick down), the speed is changed from 6th speed to 5th speed, the clutch C3 is engaged from the released state, and the brake B2 is released from the engaged state will be described. To do.

  In S110, ECT_ECU 1020 determines whether engine 100 is executing acceleration shock suppression control. The acceleration shock suppression control is executed by the control device disclosed in Patent Document 1, and the direction of torque from the engine 100 to the drive wheels is reversed when the acceleration is shifted from the non-acceleration time. This is to avoid the acceleration shock at the time, and the output of the engine 100 is suppressed by narrowing the opening of the throttle valve. If engine 100 is performing acceleration shock suppression control (YES in S110), the process proceeds to S120. Otherwise (NO in S110), this process ends.

  In S120, ECT_ECU 1020 calculates integrated time ΣT from the start of shifting. In S130, ECT_ECU 1020 determines whether or not integrated time ΣT from the start of shifting is greater than a threshold value. If accumulated time ΣT from the start of shifting is larger than the threshold value (YES in S130), it is determined that the torque phase has ended and the inertia phase has started, and the process proceeds to S140. If not (NO in S130), the process proceeds to S150.

  Note that the determination that the torque phase has ended and the inertia phase has started is not limited to the determination made based on the accumulated time ΣT from the start of the shift. For example, based on the deviation between the input shaft rotational speed NIN before shifting determined from the output shaft rotational speed NOUT and the gear ratio of the automatic transmission 300 and the actually detected input shaft rotational speed NIN, shift control is performed. May be performed based on the hydraulic pressure control value and the clutch capacity calculated from the hydraulic pressure response coefficient.

  In S140, ECT_ECU 1020 stops the acceleration shock suppression control. In S150, ECT_ECU 1020 continues the acceleration shock suppression control.

  An operation of a vehicle equipped with 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 the driver depresses the accelerator pedal from the state where the gearbox of the automatic transmission 300 is 6th and the vehicle is running and the driver is not operating the accelerator pedal, a clutch-to-clutch power-on downshift is started (S100). At YES). That is, a shift determination is made based on the automatic shift diagram based on the throttle opening of the engine 100 and the vehicle speed, and in this case, a downshift from the sixth speed to the fifth speed is started. At this time, in this shift control, it is assumed that the driver holds the accelerator pedal in a substantially constant operation and is downshift controlled in a power-on state in which power is transmitted from the engine 100 to the wheels during the shift. .

  If acceleration shock suppression control is being executed for engine 100 (YES in S110), if accumulated time ΣT from the start of shifting is greater than the threshold value (YES in S130), the torque phase has already ended. It is determined that the inertia phase has started.

  When the inertia phase is started, the acceleration shock suppression control of the engine 100 is stopped (S140).

  FIG. 4A shows changes with time of various state quantities in the present invention. For comparison, FIG. 4B shows temporal changes in various state quantities in the prior art.

  At time T (1) in FIGS. 4A and 4B, the accelerator pedal is depressed and the throttle valve starts to open. Conventionally, even if the torque phase is ended and the inertia phase is started, the acceleration shock suppression control is performed until time T (4). In the present invention, the acceleration shock suppression control is terminated at a timing earlier than the time T (4). That is, when it is determined that the inertia phase is disclosed at time T (2) shown in FIG. 4A, the acceleration shock suppression control is stopped (S140). By canceling the acceleration shock suppression control, the engine torque can be immediately increased to increase the input shaft rotational speed NIN (correlation of the rotational speed NE of the engine 100) during the inertia phase. If it is determined that the inertia phase has been started, it is no longer possible to transmit torque, so there is no need to execute control to suppress acceleration shock.

  By stopping the control for suppressing the acceleration shock, the rotational speed of the engine 100 can be quickly increased and the torque of the engine 100 can be increased. For this reason, the arrival of the turbine rotational speed NT at the synchronized rotational speed after the shift required until time T (5) in FIG. 4 (B) only reaches time T (3) as shown in FIG. 4 (A). No longer needed. This indicates that a delay at the end of shifting is avoided. Furthermore, since the turbine rotational speed NT quickly increases in this way, the acceleration response after the shift is improved, and the hesitation (feeling of breath) associated with the shift is eliminated.

  As described above, according to the ECT_ECU that is the control device according to the present embodiment, when the engine output for avoiding the acceleration shock is suppressed during the power-on downshift of the clutch-to-clutch, the torque phase is When the inertia phase starts and the torque is not transmitted, there is no need to avoid acceleration shock, so stop engine output to avoid acceleration shock, increase engine torque, and shift Can be promptly terminated to improve responsiveness. Further, since the torque of the engine after the shift is increased rapidly, a good acceleration feeling after the shift can be realized.

  For example, the clutch-to-one-way clutch shift from the fifth speed to the fourth speed is the same as the clutch-to-clutch shift described above. Furthermore, the acceleration shock suppression control of the engine is executed not only at the time of power-on downshift, but also when the accelerator pedal is depressed at the start of the inertia phase during a coast downshift, for example. When it is detected that the engine has been detected, the acceleration shock suppression control of the engine is stopped.

  As means for performing the acceleration shock suppression control corresponding to the “output limiting means” in the claims, the output of the engine 100 is limited by restricting the throttle valve opening, and the output is limited by adjusting the ignition timing and the valve timing. Alternatively, the output may be limited by reducing the number of combustion cylinders. Further, in the case of a hybrid drive device in which a generator is connected to the output shaft of engine 100, the direct amount of output torque of engine 100 reaching the transmission may be reduced by increasing the regeneration amount of the generator.

  The acceleration shock suppression control is also executed when an automatic operation such as a well-known follow-up running control is performed. In this case, it is preferable to determine that the vehicle shifts to the acceleration state based on the driving force request from the following traveling control device.

  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 figure which shows the control structure of the program of the shift control process performed by ECU. It is a timing chart which shows operation | movement of the vehicle by which the automatic transmission which concerns on embodiment of this invention is mounted.

Explanation of symbols

  100 engine, 200 torque converter, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 240 stator, 250 one-way clutch, 300 automatic transmission, 310 input clutch, 400 engine speed sensor, 410 turbine speed sensor, 420 Output shaft rotational speed sensor, 1000 ECU, 1010 engine ECU, 1020 ECT_ECU.

Claims (2)

A vehicle control device comprising a power source, drive wheels, and an automatic transmission provided between the power source and the drive wheels ,
And acceleration shock suppression means for suppressing acceleration shock that occurs when the direction of torque to the drive wheel is reversed from the power source by limiting the output of the power source when the vehicle shifts to the accelerating state ,
Detecting means for detecting whether or not the control by the acceleration shock suppressing means is being executed;
Shift detection means for detecting whether a power-on downshift of the automatic transmission is being performed;
When the power-on downshift is being performed, when said that control by acceleration shock suppression means is running is detected, at the time when the power-on downshift of the phase is shifted to the inertia phase wherein to stop the control according to acceleration shock suppression means, and a stop means for controlling the acceleration shock suppression means, the control apparatus for a vehicle. The vehicle control device according to claim 1, wherein the acceleration shock suppression means includes means for restricting an opening degree of a throttle valve of an engine.

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