JP2011179584A - Controller of automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of an automatic transmission which prevents an unnecessary increase in the number of engine revolutions and prevents deterioration in fuel efficiency by properly calculating a standby pressure when a shift from an inertia travel condition, wherein the number of input revolutions is lower than the number of output revolutions, to a forward drive condition is carried out. <P>SOLUTION: In the controller of the automatic transmission inputting an output of an engine mounted on a vehicle through a torque converter having a lock-up clutch to vary speed, when the lock-up clutch is released and it is in an inertia travel condition wherein the number of output revolutions (the number of revolutions NM of a main MS) of the torque converter is higher than the number of input revolutions (the number of engine revolutions NE), it is determined whether torque is required through accelerator pedal operation by a driver or not (S10). When it is determined that torque is required, an oil pressure control value showing a standby pressure to be supplied to the lock-up clutch is calculated based on the required torque (from S12 to S16). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission, and more specifically to a device that appropriately calculates a preparatory pressure when an accelerator pedal operation is performed from an inertial running state.

  In Patent Document 1 below, when a transition is made from a reverse drive state (inertia running state) in which the output speed of the torque converter exceeds the input speed to a forward drive state in which the input speed exceeds the output speed, the turbine speed or engine Slip control (engagement control) is permitted when a permission condition such as the rotational speed is within a predetermined range, the water temperature is within a predetermined range, and gear shifting is completed.

Japanese Patent No. 2650172

  In the technique described in Patent Document 1, the above-described configuration allows lockup in a region where it is difficult to control the capacity of the lockup clutch such as a coasting state where the output speed of the torque converter exceeds the input speed. Shocks due to sudden changes in actual clutch control pressure are avoided.

  By the way, when transitioning from such an inertia running state to a positive drive state, a transition is made to an engagement control section for engaging and controlling the lockup clutch via a preparation section for supplying a preparation pressure. As a preparatory pressure in technology, etc., a fixed value is usually output for a certain period of time, so the engine speed rises unnecessarily and gives a sense of incongruity, or the time until the start of engagement control increases and fuel efficiency decreases. There is inconvenience to do.

  The object of the present invention is to solve the above-mentioned problems and to appropriately calculate the preparation pressure when shifting from the inertia running state where the input rotational speed is lower than the output rotational speed to the positive drive state, thereby preventing an unnecessary increase in engine speed. An object of the present invention is to provide a control device for an automatic transmission that suppresses and prevents a decrease in fuel consumption performance.

  In order to solve the above-described problem, according to claim 1, in the control device for an automatic transmission that changes the speed by inputting the output of an engine mounted on a vehicle via a torque converter having a lock-up clutch, A driver torque request for determining whether or not torque is requested through the accelerator pedal operation by a driver when the lockup clutch is released and the output speed of the torque converter exceeds the input speed A determination unit, and a hydraulic control value calculation unit that calculates a hydraulic control value indicating a preparatory pressure to be supplied to the lockup clutch based on the requested torque when it is determined that the torque is requested. Configured.

  In the control apparatus for an automatic transmission according to claim 2, the hydraulic pressure control value calculation means includes a hydraulic pressure control value obtained through an experiment in advance and an original pressure of the hydraulic pressure actually generated in the lockup clutch. The hydraulic pressure control value is calculated according to a characteristic set based on a relationship with a certain line pressure.

  In the automatic transmission control apparatus according to a third aspect, the hydraulic pressure control value calculating means is configured to calculate the hydraulic pressure control value when a slip amount of the lockup clutch falls below a set value.

  In the automatic transmission control device according to claim 4, the hydraulic control value calculation means permits the engagement control of the lockup clutch when the slip amount of the lockup clutch is reversed from decrease to increase. It was configured as follows.

  In the automatic transmission control device according to claim 1, when in the inertial running state, it is determined whether or not torque is requested through the accelerator pedal operation by the driver, and when it is determined that torque is requested, Based on the requested torque, in other words, the hydraulic pressure control value indicating the preparatory pressure to be supplied to the lockup clutch is calculated so as to increase when the required torque is large. Instead, based on the requested torque, in other words, it is calculated so as to increase if the requested torque is large, so that an unnecessary increase in engine rotation can be suppressed. In addition, since the preparation pressure is calculated to be large, it is possible to shift to engagement control at an early stage, and it is possible to prevent a decrease in fuel consumption performance.

  In the control apparatus for an automatic transmission according to claim 2, based on a relationship between a hydraulic pressure control value obtained through an experiment in advance and a line pressure that is an original pressure of the hydraulic pressure actually generated in the lockup clutch. Since the hydraulic control value is calculated according to the set characteristic, in addition to the above-described effects, it is possible to consider a delay in the response characteristic of the lockup clutch with respect to the hydraulic control value.

  In other words, when there is a delay, the hydraulic pressure control value can be calculated so as to absorb the delay, so that the preparation section and the engagement control section can be smoothly continued without shock.

  The control device for the automatic transmission according to claim 3 is configured to calculate the hydraulic pressure control value when the slip amount of the lockup clutch falls below the set value. Can be calculated at a more appropriate time.

  The automatic transmission control device according to claim 4 is configured to permit the engagement control of the lockup clutch when the slip amount of the lockup clutch is reversed from the decrease to the increase. In addition, the transition timing to the engagement control can be determined more appropriately.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an entire automatic transmission control apparatus according to an embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram partially showing a hydraulic circuit of the transmission of FIG. 1 centering on a torque converter. It is a flowchart which shows operation | movement of the control apparatus of the automatic transmission shown in FIG. 3 is a time chart for explaining the processing shown in the flow chart. FIG. 4 is a subroutine flowchart showing a process for calculating a hydraulic pressure control value in the flowchart of FIG. 3.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments for implementing a control device for an automatic transmission according to the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing an overall control apparatus for an automatic transmission according to an embodiment of the present invention.

  In the following description, the symbol T / M indicates an automatic transmission (hereinafter referred to as “transmission”). The transmission T / M is mounted on a vehicle (not shown) and is a parallel shaft stepped type having speed stages of five forward speeds and one reverse speed.

  The transmission T / M includes a main shaft (input shaft) MS connected to an output shaft 10 connected to a crankshaft of an engine (internal combustion engine) E via a torque converter 12 having a lockup mechanism L, and the main shaft. And a counter shaft (output shaft) CS connected to the MS via a plurality of gear trains. The engine E includes a plurality of cylinders and a spark ignition engine using gasoline as fuel.

  The lockup mechanism L of the torque converter 12 includes a lockup clutch LC, and engages the main shaft MS with the output shaft 10 (more precisely, slips) according to the supplied hydraulic pressure (pressure of the hydraulic oil ATF). .

  The ratio ETR of the rotation speed of the main shaft MS to the rotation speed of the output shaft 10 indicates the slip ratio of the torque converter 12, more specifically, the lockup clutch LC, in other words, the slip amount (degree of engagement). The difference SLIP between the rotational speed of the main shaft MS and the rotational speed of the main shaft MS also indicates the slip amount (engagement degree) of the torque converter 12, more specifically, the lockup clutch LC.

  A main first speed gear 14, a main second speed gear 16, a main third speed gear 18, a main fourth speed gear 20, a main fifth speed gear 22, and a main reverse gear 24 are supported on the main shaft MS.

  The counter shaft CS has a counter first speed gear 28 meshing with the main first speed gear 14, a counter second speed gear 30 meshing with the main second speed gear 16, a counter third speed gear 32 meshing with the main third speed gear 18, The counter 4th gear 34 meshed with the main 4th gear 20, the counter 5th gear 36 meshed with the main 5th gear 22, and the counter reverse gear 42 connected to the main reverse gear 24 via the reverse idle gear 40 are supported. Is done.

  In the above description, when the main first-speed gear 14 that is rotatably supported on the main shaft MS is coupled to the main shaft MS by a first-speed hydraulic clutch (friction engagement element; the same applies hereinafter) C1, the first speed (gear, speed stage) is coupled. ) Established.

  When the main second-speed gear 16 that is rotatably supported on the main shaft MS is coupled to the main shaft MS by the second-speed hydraulic clutch C2, the second speed (gear, speed stage) is established. When the counter third-speed gear 32 that is rotatably supported on the countershaft CS is coupled to the countershaft CS by the third-speed hydraulic clutch C3, the third speed (gear, speed stage) is established.

  With the counter fourth speed gear 34 supported rotatably on the counter shaft CS coupled to the counter shaft CS by the selector gear SG, the main fourth speed gear 20 supported relatively rotatably on the main shaft MS is changed to the fourth speed-reverse. When the hydraulic clutch C4R is coupled to the main shaft MS, the fourth speed (gear, speed stage) is established.

  Further, when the counter fifth-speed gear 36 that is rotatably supported on the countershaft CS is coupled to the countershaft CS by the fifth-speed hydraulic clutch C5, the fifth speed (gear, speed stage) is established.

  Further, with the counter reverse gear 42 supported relative to the countershaft CS rotatably coupled to the countershaft CS by the selector gear SG, the main reverse gear 24 supported relative to the main shaft MS relative to the countershaft CS is connected to the 4-speed-reverse. When the main hydraulic clutch C4R is coupled to the main shaft MS, a reverse speed stage is established.

  The rotation of the counter shaft CS is transmitted to the differential D through a final drive gear 46 and a final driven gear 48, and then a vehicle (not shown) on which the engine E and the transmission T / M are mounted via the left and right drive shafts 50, 50. )) To the drive wheels W, W.

  A shift lever 54 is provided near the floor of the vehicle driver's seat (not shown), and one of eight ranges, P, R, N, D5, D4, D3, 2, 1 is selected by the driver's operation. The

  A throttle valve (not shown) disposed in the intake passage (not shown) of the engine E is connected to a DBW (Drive By Wire) mechanism 55. That is, the throttle valve is mechanically disconnected from an accelerator pedal (not shown) and driven by an actuator (not shown) such as an electric motor.

  A throttle opening sensor 56 is provided in the vicinity of the actuator of the DBW mechanism 55 and outputs a signal indicating the throttle opening THHF through the rotation amount of the actuator. A vehicle speed sensor 58 is provided in the vicinity of the final driven gear 48 and outputs a signal indicating the vehicle speed V every time the final driven gear 48 makes one rotation.

  Further, a crank angle sensor 60 is provided in the vicinity of the camshaft (not shown), and a CYL signal is subdivided at a predetermined crank angle of a specific cylinder, a TDC signal is subdivided at a predetermined crank angle of each cylinder, and a crank obtained by subdividing the predetermined crank angle. A CRK signal is output for each angle (for example, 15 degrees). Further, an absolute pressure sensor 62 is provided downstream of the throttle valve arrangement position of the intake passage of the engine E, and outputs a signal indicating the intake pipe absolute pressure (engine load) PBA.

  A first rotation speed sensor 64 is provided in the vicinity of the main shaft MS and outputs a signal indicating the rotation speed (input rotation speed of the transmission T / M) NM of the main shaft MS, and in the vicinity of the counter shaft CS. Is provided with a second rotational speed sensor 66, which outputs a signal indicating the rotational speed of the countershaft CS (output rotational speed of the transmission T / M) NC.

  Further, a shift lever position sensor 68 is provided in the vicinity of the shift lever 54 mounted in the vicinity of the vehicle driver's seat, and outputs a signal indicating the position selected by the driver among the eight positions (ranges) described above. To do.

  As will be described later, a temperature sensor 70 is provided in the vicinity of the reservoir of the hydraulic circuit O of the transmission T / M to output a signal proportional to the oil temperature (temperature of the hydraulic oil Automatic Transmission Fluid) TATF and each hydraulic clutch Cn. Are respectively provided with hydraulic switches 72 (not shown in FIG. 2), and outputs ON signals when the hydraulic pressure supplied to each hydraulic clutch Cn reaches a predetermined value.

  A brake switch 74 is provided in the vicinity of a brake pedal (not shown) in the vehicle driver's seat and outputs an ON signal in response to the driver's operation of the brake pedal, and an accelerator in the vicinity of the accelerator pedal (not shown). An opening degree sensor 76 is provided to generate an output corresponding to the driver's accelerator opening (accelerator pedal depression amount) AP.

  Outputs of these sensors 56 and the like are sent to an ECU (electronic control unit) 80.

  The ECU 80 includes a microcomputer including a CPU 82, ROM 84, RAM 86, an input circuit 88, and an output circuit 90. The microcomputer includes an A / D converter 92.

  The output of the sensor 56 and the like is input into the ECU 80 via the input circuit 88, the analog output is converted into a digital value via the A / D converter 92, and the digital output is processed by a waveform shaping circuit or the like. It is processed through a circuit (not shown) and stored in the RAM 86.

  The time interval between the output of the vehicle speed sensor 58 and the output of the CRK signal of the crank angle sensor 60 is measured by a counter (not shown), and the vehicle speed V and the engine speed NE are detected. The outputs of the first rotational speed sensor 64 and the second rotational speed sensor 66 are also counted, and the input shaft rotational speed NM and the output shaft rotational speed NC of the transmission are detected.

  As shown, the hydraulic circuit O of the transmission T / M includes shift solenoids SL1 to SL5 and linear solenoids SL6 to SL9. FIG. 2 is a hydraulic circuit diagram partially showing the hydraulic circuit O of FIG.

  The hydraulic circuit O is provided with a hydraulic pump O1. The hydraulic pump O1 is driven by the engine E, pumps up the hydraulic oil ATF stored in the above-described reservoir (indicated by reference numeral O2), and sends it to the PH regulator valve O3.

  The PH regulator valve O3 adjusts the discharge pressure of the hydraulic pump O1 in accordance with the traveling state of the vehicle, generates a PH pressure (original pressure or line pressure), and supplies it to the oil passage O4.

  The oil passage O4 is connected to each hydraulic clutch Cn and to the torque converter 12. That is, the lockup clutch LC of the torque converter 12 includes a back pressure chamber LC1 and an internal pressure chamber LC2 connected to the back pressure chamber LC1. The internal pressure chamber LC2 is connected to an oil passage O5 branched from the oil passage O4 and supplied with hydraulic pressure, while the back pressure chamber LC1 is connected to a linear solenoid SL8 to adjust the amount of engagement.

  When the lockup clutch LC is released, the back pressure chamber LC1 is connected to the oil passage O5 branched from the oil passage O4 and supplied with hydraulic pressure, while the internal pressure chamber LC2 is connected to the drain X through the oil passage O6. The hydraulic pressure is discharged.

  In the torque converter 12, the lock-up clutch LC engages (slips) the main shaft MS with the output shaft 10 at a pressure corresponding to the differential pressure (supply hydraulic pressure) between the back pressure chamber LC1 and the internal pressure chamber LC2.

  In the ECU 80, the CPU 82 determines a destination stage or a target stage (gear ratio), and excites / de-energizes shift solenoids SL1 to SL5 arranged in the hydraulic circuit O via an output circuit 90 and a voltage supply circuit (not shown). To control the switching of the clutch oil passage.

  Further, the CPU 82 controls the hydraulic pressure supplied to the hydraulic clutch Cn related to gear shifting by exciting / de-energizing the linear solenoids SL6, SL7, and energizing / de-energizing the linear solenoid SL8 to back pressure chamber LC1 of the lockup clutch LC. In addition, the PH pressure is adjusted by exciting / de-energizing the linear solenoid SL9.

  The CPU 82 determines the fuel injection amount and ignition timing of the engine E, supplies the determined injection amount of fuel via an injector (not shown), and is determined via an ignition device (not shown). The fuel / intake fuel mixture injected in accordance with the ignition timing is ignited, but since they are not directly related to the present invention, further explanation is omitted.

  Next, the operation of the automatic transmission control device according to the present invention will be described.

  FIG. 3 is a flow chart showing the processing, and FIG. 4 is a time chart showing the processing. The program shown in FIG. 3 is executed by the CPU 82 every predetermined time.

  In the following description, it is determined in S10 whether or not the accelerator opening AP exceeds a predetermined value.

  Specifically, the lockup clutch LC is released (not engaged), and the output rotational speed (rotational speed NM of the main shaft MS) of the torque converter 12 as shown in FIG. 4 is the input rotational speed (engine rotational speed). NE), it is determined whether torque is requested by the driver through the accelerator pedal operation.

  When the result in S10 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S12. It is judged whether it is below zero or the vicinity thereof. In the time chart of FIG. 4, this determination is affirmed at time t1.

  When the result in S12 is negative, the program proceeds to S14, where a fixed value is set to the hydraulic pressure control value indicating the preparatory pressure to be supplied to the lockup clutch LC. When the result is affirmative, the program proceeds to S16, where the hydraulic control value is set to the required torque. Calculate accordingly.

  FIG. 5 is a sub-routine flowchart showing the processing.

  Explaining below, in S100, it is determined whether or not the calculation of the hydraulic pressure control value is the first time, that is, the first program loop in the processing of the flowchart of FIG. 3, and if affirmative, the process proceeds to S102 and the output torque of the engine E is calculated. To do.

  This is calculated by searching an appropriate characteristic from the rotational speed NE of the engine E and a load (for example, the throttle opening THHF accelerator opening AP). In this embodiment, the DBW mechanism 55 is provided, and the throttle opening THHF is controlled according to the accelerator opening AP detected there. Therefore, the throttle opening THHF is a torque requested by the driver through the accelerator pedal operation. Indicates.

  Any parameter may be used as long as it indicates the torque requested by the parameter driver indicating the load through the accelerator pedal operation. For example, the absolute pressure PBA in the intake pipe may be used.

  Next, in S104, a target LC differential pressure (a target value of a differential pressure between the back pressure chamber LC1 and the internal pressure chamber LC2 of the lockup clutch LC) is calculated.

  This is determined in advance from the calculated target LC torque (target value of the transfer torque of the lockup clutch LC) from the engine E application torque calculated in S102, and from the calculated target LC torque, target LC slip amount, and oil temperature. The LC differential pressure required to achieve the target LC torque is retrieved and calculated according to the characteristics.

  This preset characteristic is obtained by mounting an experimentally measured value in the ROM 84 of the ECU 80. That is, the supply hydraulic pressure to the lockup clutch LC (that is, the differential pressure between the back pressure chamber LC1 and the internal pressure chamber LC2) obtained through an experiment in advance and the LC transmission torque actually generated in the lockup clutch LC by the supply hydraulic pressure. The LC differential pressure required to achieve the target LC torque is calculated according to the characteristic set based on the relationship.

  Next, in S106, a hydraulic pressure control value (a control value to be energized to the linear solenoid SL8) is calculated based on the calculated LC differential pressure. When the result in S100 is negative, the program proceeds to S108, and the previous value is held as the hydraulic pressure control value.

  Returning to the description of the flow chart of FIG. 3, the process then proceeds to S18 to output the hydraulic pressure control value calculated as described above (that is, supply hydraulic pressure).

Next, in S20, it is determined whether or not the slip amount of the torque converter 12 exceeds the previous value, in other words, whether or not the slip amount has been reversed from decrease to increase, and if not, the subsequent processing is skipped.

  On the other hand, when the result in S20 is affirmative, the program proceeds to S22, and the engagement control of the lockup clutch LC is permitted. In the time chart of FIG. 4, the determination in S20 is affirmed at time t2, and the engagement control is permitted.

  As described above, in this embodiment, the control of the automatic transmission (transmission) T / M that changes the speed by inputting the output of the engine E mounted on the vehicle via the torque converter 12 having the lock-up clutch LC. In the device (ECU 80), the lockup clutch LC is disengaged and the inertial running state in which the output rotational speed of the torque converter 12 (rotational speed NM of the main shaft MS) exceeds the input rotational speed (engine rotational speed NE). The driver torque request determining means (S10) for determining whether or not torque is requested through the accelerator pedal operation by the driver, and when it is determined that the torque is requested, based on the requested torque. Hydraulic control value calculation for calculating a hydraulic control value indicating a preparatory pressure to be supplied to the lockup clutch Means (S12 to 18) are provided, so that the preparatory pressure is not a fixed value but is calculated based on the requested torque, in other words, if the requested torque is large, it is calculated to increase. As shown by a solid line, an unnecessary increase in engine rotation as shown by a broken line in FIG. 4 can be suppressed.

  Further, since the preparation pressure is calculated to be large, it is possible to shift to the engagement control at t2 before time t3 as early as in FIG. 4, and it is possible to prevent a decrease in fuel consumption performance.

  The hydraulic control value calculation means is a characteristic set based on a relationship between a hydraulic control value obtained through an experiment in advance and a line pressure that is the original pressure of the hydraulic pressure actually generated in the lockup clutch LC. Therefore, in addition to the above-described effects, a delay in response characteristics of the lockup clutch LC with respect to the hydraulic control value can be taken into consideration.

  In other words, when there is a delay, the hydraulic pressure control value can be calculated so as to absorb the delay, so that the preparation section and the engagement control section can be smoothly continued without shock.

  The hydraulic control value calculation means is configured to calculate the hydraulic control value when the slip amount of the lockup clutch LC falls below a set value (S12, S16). The control value can be calculated at a more appropriate time.

  Further, the hydraulic pressure control value calculating means is configured to permit engagement control of the lockup clutch when the slip amount of the lockup clutch LC is reversed from decrease to increase (S20, S22). In addition to the effect, it is possible to more appropriately determine the transition timing to the engagement control.

  Although the slip amount is used in the process of FIG. 3, the ratio of the output rotational speed to the input rotational speed may be used. That is, in this specification, the target “slip amount” includes both the difference in the rotational speed and the ratio of the rotational speed.

  Although the present invention has been described by taking a parallel shaft type automatic transmission as an example, the present invention is also applicable to a planetary type automatic transmission.

  T / M automatic transmission (transmission), E engine (internal combustion engine), O hydraulic circuit, 12 torque converter, L lockup mechanism, LC lockup clutch, LC1 back pressure chamber, LC2 internal pressure chamber, 14, 16, 18, 20, 22, 24, 28, 30, 32, 34, 36, 42 Gear, Cn Hydraulic clutch (friction engagement element), 55 DBW mechanism, 58 Vehicle speed sensor, 60 Crank angle sensor, 62 Absolute pressure sensor, 64, 66 Rotation speed sensor, 76 accelerator opening sensor, 80 Electronic control unit (ECU)

Claims (4)

  In a control device for an automatic transmission that shifts by inputting an output of an engine mounted on a vehicle via a torque converter having a lock-up clutch, the lock-up clutch is released, and the output speed of the torque converter is Is in the inertial running state exceeding the input rotational speed, the driver torque request determining means for determining whether or not torque is requested through the accelerator pedal operation by the driver, and when it is determined that the torque is requested, the request And a hydraulic pressure control value calculating means for calculating a hydraulic pressure control value indicating a preparatory pressure to be supplied to the lockup clutch based on the torque that has been applied.   The hydraulic pressure control value calculating means is configured to perform the hydraulic pressure control value according to a characteristic set based on a relationship between a hydraulic pressure control value obtained through an experiment in advance and a line pressure that is an original pressure of the hydraulic pressure actually generated in the lockup clutch. 2. The control device for an automatic transmission according to claim 1, wherein a control value is calculated.   3. The control apparatus for an automatic transmission according to claim 1, wherein the hydraulic pressure control value calculation means calculates the hydraulic pressure control value when a slip amount of the lockup clutch falls below a set value.   The hydraulic pressure control value calculation means permits the lock-up clutch engagement control when the slip amount of the lock-up clutch is reversed from decrease to increase. Automatic transmission control device.

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