JP5357078B2 - Control device for automatic transmission - Google Patents

Description

  The present invention relates to a control device for an automatic transmission, and more specifically to a device that optimally engages a lock-up clutch of a torque converter.

  The technology described in Patent Document 1 below calculates the time change gradient by dividing the step between the clutch capacity control command value corresponding to the detected torque and the control command value of the clutch capacity 0 by the time at the first control of the lockup clutch area. It has been proposed that the lock-up clutch engagement time is controlled by increasing the command value with the obtained time-varying gradient after the next time.

  Further, the technique described in Patent Document 2 proposes to obtain a time-series change in the target engine speed, obtain a target slip amount from a difference from the turbine speed, and perform slip control of the torque converter so as to be the target slip amount. doing.

JP 2004-232870 A JP 2005-016671 A

  When the lock-up clutch (LC) is engaged from the non-engaged (OFF-off) state (ON-on), if it is quickly engaged, an LC on-shock will occur, while if it is gently engaged, engine rotation will be reduced. Absorption slows down, reducing fuel efficiency and durability of the lock-up clutch.

  In that regard, the conventional technology takes into account the effects of individual variations and changes in hydraulic response characteristics due to oil temperature, and as a result of providing a safety margin so that LC on shock does not occur in all states, the LC on time As a result, the fuel consumption performance and the durability of the lock-up clutch may be reduced.

  The object of the present invention is to solve the above-mentioned problems and to turn on the lock-up clutch quickly so as not to cause an LC on shock, and to prevent the fuel efficiency and the durability of the lock-up clutch from being lowered. It is to provide a control device for an automatic transmission.

  In order to solve the above-described problems, in the 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, A target slip amount calculating means for calculating a target slip amount of the lockup clutch according to the obtained characteristics; and an engine speed for calculating a reduction amount of the engine speed necessary to absorb the calculated target slip amount. Number reduction amount calculation means, target engagement time calculation means for calculating a target engagement time of the lockup clutch from the calculated reduction amount of the engine speed according to a predetermined characteristic, the engine and the torque converter So that the inertia torque of the lockup clutch becomes maximum during the calculated target engagement time. A transmission torque calculating means for calculating a reaching torque, a hydraulic pressure for calculating a hydraulic pressure supplied to the lockup clutch so as to be the calculated transmission torque, and calculating a hydraulic pressure control value so as to be the calculated hydraulic pressure And a control means.

  In the control apparatus for an automatic transmission according to claim 2, the transmission torque calculation means is configured to take a time at which the inertia torque of the engine and the torque converter is ½ or near the calculated target engagement time. The transmission torque of the lockup clutch is calculated so as to be maximized.

  In the control device for an automatic transmission according to claim 1, a target slip amount of the lockup clutch is calculated, and a reduction amount of the engine speed necessary to absorb the calculated target slip amount is calculated. Then, the target engagement time of the lockup clutch is calculated from the amount of decrease in the engine speed calculated according to the characteristic obtained in advance, and the maximum of the target engagement time during which the inertia torque of the engine and the torque converter is calculated The transmission torque of the lockup clutch is calculated so that the calculated transmission torque is obtained, and the hydraulic pressure control value is calculated by calculating the hydraulic pressure supplied to the lockup clutch so that the calculated transmission torque is obtained. The state can always be estimated in a feed-forward manner, and the lockup clutch can be quickly turned on, resulting in fuel efficiency. It is not possible to reduce the durability of the lock-up clutch.

  Also, the transmission torque of the lockup clutch is calculated so that the inertia torque of the engine and the torque converter becomes the maximum during the calculated target engagement time, and the hydraulic pressure supplied to the lockup clutch is adjusted so as to be the transmission torque. By calculating the hydraulic pressure control value by calculation, it is possible to optimally control the speed of change of the engine speed, so that LC on shock does not occur.

  In the control device for an automatic transmission according to claim 2, the lockup clutch is controlled so that the inertia torque of the engine and the torque converter is maximized at a half of the calculated target engagement time or a time in the vicinity thereof. Since the transmission torque is calculated, it is possible to more reliably prevent the occurrence of LC on shock in addition to the above effects.

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 explanatory drawing which shows the structure of the torque converter of FIG. 1 in detail. It is a flowchart which shows operation | movement of the control apparatus of the automatic transmission shown in FIG. FIG. 4 is an explanatory diagram of characteristics used for determining whether or not the LCON control permission condition is within the flowchart. 5 is a time chart for explaining the control shown in the flow chart of FIG. FIG. 5 is a sub-routine flow chart showing the initial LCON processing of the flow chart. 7 is an explanatory diagram showing characteristics of the target slip amount calculated by the flowchart of FIG. FIG. 7 is a sub-routine flowchart showing a calculation process of a target absorption LC slip amount in the flowchart of FIG. 7. FIG. 7 is a sub-routine flow chart showing a calculation process of a target ON time of the flow chart. FIG. 7 is a sub-routine flow chart showing a calculation process of a target inertia absorption amount for each control cycle of the flowchart of FIG. 7. 5 is a sub-routine flow chart showing the LCON processing of the flow chart. FIG. 12 is a sub-routine flowchart showing a calculation process of a next target LC torque in the flowchart of FIG. 12. FIG. 14 is a sub-routine flow chart showing a calculation process of a next target inertia torque in the flowchart of FIG. 13. 14 is a time chart for explaining the processing of the flow chart. FIG. 13 is a sub-routine flowchart showing the calculation process of the LC differential pressure control value in the flowchart of FIG. 12. It is explanatory drawing which shows the characteristic of LC differential pressure calculated with the flow chart of FIG. It is explanatory drawing which shows the characteristic of LC differential pressure final value computed with the flow chart of FIG. It is explanatory drawing which shows the characteristic of LC differential pressure final value line pressure correction value calculated with the flowchart of FIG. FIG. 17 is an explanatory diagram showing LC differential pressure transient characteristics calculated by the flow chart of FIG. 16.

  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 rotational speed of the main shaft MS to the rotational speed of the output shaft 10 indicates the slip ratio (engagement degree) of the torque converter 12, more specifically, the lockup clutch LC, and the rotational speed of the output shaft 10 and the main shaft. The speed difference SLIP of the MS also indicates the slip ratio (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 for a specific cylinder, a TDC signal is subdivided at a predetermined crank angle for each cylinder, and 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 control 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.

  The CPU 82 controls the hydraulic pressure supplied to the hydraulic clutch Cn related to the shift 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.

  FIG. 3 is an explanatory diagram showing in detail the structure of the torque converter (torque converter) 12 of FIG. Torque (hereinafter referred to as “LC transmission torque”) TLC transmitted by the lock-up clutch LC of the torque converter 12 is calculated according to the theoretical relational expression shown in the figure.

  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. 4 is a flowchart showing the processing. The illustrated program is executed by the CPU 82 every predetermined time.

  In the following, it is determined in S10 whether or not the LCON control permission condition is satisfied. This is performed by selecting a corresponding characteristic (LC control map) from the current gear position and determining whether or not the vehicle is in the LCON region from the accelerator opening AP and the vehicle speed V.

  FIG. 5 is an explanatory diagram showing the processing. As shown in the figure, the LC-on control permission condition (region where the LCON (engagement) control is performed) is set by the shift speed (speed ratio) SH, the accelerator pedal opening AP, and the vehicle speed V. In order to prevent control hunting, hysteresis is provided at the boundary line of the region.

  When the result in S10 is negative, the subsequent processing is skipped, and when the result is affirmative, the process proceeds to S12. It is determined whether this is the first program loop after affirmation.

  Before continuing the description of the flow chart of FIG. 4, the control according to this embodiment will be outlined with reference to FIG. FIG. 6 is a time chart for explaining the control shown in the flow chart of FIG.

  In this embodiment, a target slip amount is calculated in accordance with a predetermined characteristic, and then a target absorption LC slip amount, that is, a reduction amount of the engine speed NE necessary to absorb the calculated target slip amount is calculated. To do.

  Next, a target ON time (target engagement time of the lock-up clutch LC) is calculated from the oil temperature TATF and the calculated target absorption LC slip amount according to the characteristics obtained in advance.

  Next, the lockup clutch LC is set so that the inertia torque TI (shown in FIG. 3) of the engine E and the torque converter 12 becomes maximum during the calculated target ON time, more specifically, at half or near the target ON time. LC transmission torque TLC to be transmitted is calculated.

  That is, the maximum value of the shock that occurs as the engine speed NE decreases due to turning on the lockup clutch LC, in other words, the maximum value of the inertia torque TI of the engine E and the torque converter 12 is half of the target ON time. The engine speed is reduced by controlling the LC transmission torque TLC so that the engine rotation occurs.

  Furthermore, more specifically, the lockup clutch is controlled by the hydraulic pressure supplied to the lockup clutch LC (more precisely, the differential pressure between the back pressure chamber LC1 and the internal pressure chamber LC2) and the hydraulic pressure so that the calculated transmission torque is obtained. Based on the relationship with the LC transmission torque TLC actually generated in the LC, the hydraulic pressure supplied to the lockup clutch LC is calculated according to a preset delay characteristic, and the hydraulic pressure control value is calculated so as to be the calculated hydraulic pressure. It was configured as follows.

  Returning to the description of the flowchart of FIG. 4 on the premise of the above, when the result in S12 is affirmative, the process proceeds to S14, and the LCON initial process is executed.

  FIG. 7 is a sub-routine flowchart showing the processing.

  In the following, the target slip amount is calculated in S100. That is, the above-described target slip amount is calculated according to the characteristic obtained in advance.

  The target slip amount is calculated by the difference SLIP between the rotation speed of the output shaft 10 and the rotation speed of the main shaft MS, but may be calculated by the ratio ETR of the rotation speed of the main shaft MS to the rotation speed of the output shaft 10. That is, in this specification, the target “slip amount” includes both the rotational speed difference SLIP and the rotational speed ratio ETR.

  FIG. 8 is an explanatory diagram showing the characteristics. As shown in the figure, the target slip amount is set for each gear stage SH, the main shaft rotation speed NM, and the throttle opening THHF, and is calculated by interpolation calculation of values obtained by searching from the detected values of these parameters.

  Next, in S102, the above-described target absorption LC slip amount is calculated.

  FIG. 9 is a sub-routine flowchart showing the processing.

  First, in S200, the ON control initial target engine speed NE is calculated from the ON control initial actual engine speed NE, the actual main shaft speed NM, and the target slip amount (calculated in S100). Specifically, it is calculated by adding the ON control initial actual main shaft speed NM to the target slip amount.

  Next, in S202, the target absorption LC slip amount is calculated by dividing the ON control initial target engine speed NE from the ON control initial actual engine speed NE.

  Returning to the description of the flowchart of FIG. 7, the process then proceeds to S104 to calculate the above-described target ON time.

  FIG. 10 is a subroutine flow chart showing the processing.

  First, in S300, an appropriate characteristic set in advance is searched from the oil temperature TATF detected from the temperature sensor 70 and the target absorption LC slip amount calculated in S102, and the reference gear stage target ON time is calculated.

  Next, the routine proceeds to S302, where an appropriate characteristic set in advance is searched from the current gear position and the throttle opening THHF to calculate a target ON time search speed coefficient, and the routine proceeds to S304, where the calculated reference gear speed target ON is calculated. A target ON time is calculated by searching an appropriate characteristic set in advance from the time and the gear stage coefficient.

  Returning to the description of the flowchart of FIG. 7, the process then proceeds to S106, and the target inertia torque absorption amount for each control cycle is calculated.

  FIG. 11 is a subroutine flowchart showing the processing.

  First, in S400, the target absorption LC slip amount calculated in S102 is divided by the target ON time calculated in S104 to calculate a target absorption NE amount gradient (target value of the absorption gradient of the engine speed NE).

  Next, in S402, an appropriate characteristic is searched from the calculated target absorption NE amount inclination to calculate an average inertia torque absorption amount, and in S404, the average inertia torque absorption amount calculated in S402 and the calculation result in S104. A target inertia torque absorption amount for each control cycle is calculated by integrating the engine torque converter inertia I and the value obtained from the target ON time. That is, the target inertia torque absorption amount of the program loop period shown in the flowchart of FIG. 4 is calculated.

  Returning to the description of the flow chart of FIG. 4, when the result in S12 is negative and it is determined that the LCON control is not the first time, the process proceeds to S16 to execute the LCON process.

  FIG. 12 is a subroutine flowchart showing the processing.

  In the following, the next target LC torque is calculated in S500. In this specification, “next time” means the next control cycle, that is, the next program loop in the flow chart of FIG. Therefore, in S500, the target value of the LC torque for the next control cycle is calculated.

  FIG. 13 is a sub-routine flowchart showing the processing.

  In the following, the next engine torque TE is calculated in S600. This is calculated by searching for suitable characteristics from the rotational speed NE of the engine E and the load (for example, the throttle opening THHF).

  Next, in S602, the next target inertia torque TI, that is, the inertia torque value to be absorbed is calculated. That is, as shown in FIG. 6, the calculated value is such that the inertia torque TI of the engine E and the torque converter 12 is maximized in the middle of the calculated target ON time, more specifically, at half or near the target ON time. The inertia torque value to be absorbed is calculated by adding and subtracting.

  FIG. 14 is a sub-routine flowchart showing the processing, and FIG. 15 is a time chart explaining the processing of FIG.

  Explaining with reference to FIG. 15 (and FIG. 6), in S700, it is determined whether or not the remainder of the target absorption LC slip amount exceeds 1/2 of the target absorption LC slip amount. The target inertia torque absorption amount for each next control cycle is corrected by a predetermined amount.

  As shown at the end of FIG. 6, the predetermined amount for correcting the target inertia absorption amount is a value corresponding to the control cycle as a quotient obtained by dividing the value obtained by doubling the average inertia absorption amount by half of the target ON time. Multiply by α.

  Next, the process proceeds to S704, in which a value added and corrected by a predetermined amount is subjected to a limit process, that is, the value corrected by addition is limited so as to be not more than twice the average inertia torque absorption amount.

  On the other hand, when the result in S700 is negative, the program proceeds to S706, the target inertia torque absorption amount for each next control cycle is subtracted and corrected by a predetermined amount, and the program proceeds to S708, where the subtracted correction value is limited, that is, subtracted. Limit the value to not be less than zero.

  In FIG. 15, when the case indicated by A is the desired theoretical rotational transition, the case indicated by B is left unattended, but when the absorption of the LC slip amount as indicated by C is slow, the torque command value (next target LC torque ) Keep the peak. The peak is maintained by setting an upper limit on the inertia torque absorption amount and preventing changes in engine rotation.

  Returning to the description of the flowchart of FIG. 13, the process proceeds to S604, and the next pump torque TP is calculated according to the calculation formula shown in FIG.

  Next, in S606, the next target LC torque TLC (the target value of the LC transmission torque in the next control cycle) is calculated based on the values calculated from S600 to S604.

  Returning to the description of the flowchart of FIG. 12, the process proceeds to S502, and the LC differential pressure control value is calculated.

  FIG. 16 is a sub-routine flowchart showing the calculation process of the LC differential pressure control value.

  In the following, the LC differential pressure is calculated in S800. Specifically, the LC differential pressure (the differential pressure between the back pressure chamber LC1 and the internal pressure chamber LC2 of the lockup clutch LC) necessary for the next target LC torque calculated by the processing of the flowchart of FIG. 12 is calculated.

  More specifically, according to the characteristics shown in FIG. 17, the next target LC torque (the target value of the next control cycle of the LC transmission torque TLC) and the next target LC slip amount SLIPTN (calculated between S500 and S502 in FIG. 12). (Not shown) and the oil temperature TAFT, the LC differential pressure required to achieve the target LC torque is retrieved and calculated. The characteristics shown in FIG. 17 are obtained by mounting experimentally measured values in the ROM 84 of the ECU 80.

  That is, the supply hydraulic pressure (that is, the differential pressure between the back pressure chamber LC1 and the internal pressure chamber LC2) to the lockup clutch LC obtained in advance through experiments and the LC transmission torque TLC actually generated in the lockup clutch LC by the supply hydraulic pressure. In accordance with the characteristic set based on the above relationship, the LC differential pressure is calculated so as to obtain the calculated transmission torque necessary for realizing the calculated target LC torque.

  As shown in FIG. 17A, for example, eight types of TATF # 1 to TATF # 8 are set for each oil temperature TATF, so that the LC differential pressure is interpolated at four points on the TLC axis and the SLIPTN axis. The retrieved values are obtained for each TATF range, and are calculated by performing two-point interpolation with TATF as shown in FIG.

  Next, in S802, the LC differential pressure final value is searched. This is calculated by interpolating a value obtained by searching from the oil temperature TATF and LCICMD (control current to be energized to the linear solenoid SL8) according to the characteristics shown in FIG.

  The characteristic shown in FIG. 18 is also obtained by mounting the value measured by the single bench in the ROM 84 of the ECU 80, and defines the relationship between the control current to the linear solenoid SL8 and the LC differential pressure final value.

  Next, in S804, the LC differential pressure final value line pressure correction value is calculated. This is calculated by searching for a coefficient by performing an interpolation operation from the line pressure (PH pressure) command value PL (energization command value for the linear solenoid SL9) and LCICMD in accordance with the characteristics shown in FIG.

  The characteristic shown in FIG. 19 is also obtained by mounting the values measured by the single bench in the ROM 84 of the ECU 80. That is, since the LC differential pressure final value changes as the line pressure increases or decreases, the correction coefficient is set for each line pressure command value.

  In the flowchart of FIG. 16, the process proceeds to S806, where the LC differential pressure transient characteristic is calculated. As a result of extensive knowledge, the inventors have found that the response of the differential pressure to the hydraulic control value can be approximated by a second-order lag model.

  Therefore, the relationship between the hydraulic control value and the response characteristic of the actual differential pressure until reaching the final differential pressure value is measured in advance with a single bench or the like, and is mounted on the ROM 84 of the ECU 80 in the same manner as the data of S802, S804, etc. By arranging the data, it is possible to accurately estimate the differential pressure response based on the second-order lag model even in the actual running state.

  Specifically, according to the characteristics shown in FIGS. 20A, 20B, and 20C, three types of coefficients a (a11, a12, a21, a22), b are calculated by interpolation from the oil temperature TATF and the engine speed NE. Calculation is performed by searching for (b11, b21) and c (c11, c12), respectively.

  Returning to the description of the flow chart of FIG. 16, the process proceeds to S808, and the LC differential pressure control value is calculated by multiplying the differential pressure final value searched in S202 by the coefficient searched in S804 and S806, respectively.

  Returning to the description of the flowchart of FIG. 12, the process then proceeds to S504, where the LC command current value (LCICMD described above) is calculated so as to be the calculated LC differential pressure control value.

  In this embodiment, as described above, a control device for an 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. (ECU 80) Target slip amount calculation means (S14, S100) for calculating the target slip amount of the lock-up clutch according to characteristics obtained in advance, and the engine required to absorb the calculated target slip amount Engine speed reduction amount calculating means (S14, S102, S200) for calculating the amount of decrease in the engine speed (target absorption LC slip amount), and the engine speed reduction amount calculated in accordance with the previously determined characteristics. Target engagement time calculation means (S) for calculating the target engagement time (target ON time) of the lockup clutch 4, S104, S300 to S304), and transmission for calculating the transmission torque TLC of the lockup clutch so that the inertia torque TI of the engine E and the torque converter 12 becomes maximum during the calculated target engagement time. Torque calculation means (S16, S500, S600 to S606, S700 to S708), and the hydraulic pressure supplied to the lockup clutch LC to calculate the calculated transmission torque (S502, S800 to S808), and the calculation Since the hydraulic pressure control means (S504) for calculating the hydraulic pressure control value so as to obtain the supplied hydraulic pressure is provided, the operating state of the lockup clutch LC can always be estimated in a feed-forward manner. LC can be quickly turned on (engaged) It is not reduced and the durability of the performance and the lock-up clutch LC.

  Further, the transmission torque of the lockup clutch LC (next target LC torque TLC) is calculated so that the inertia torque TI of the engine E and the torque converter 12 becomes maximum during the calculated target engagement time (target ON time). (S700 to S708), the hydraulic pressure supplied to the lockup clutch LC is calculated so as to be the transmission torque, and the hydraulic pressure control value (LC command current value) is calculated (S800 to S808, S504). Since the NE change speed can be optimally controlled, LC on shock does not occur.

  Further, the transmission torque calculation means is configured so that the inertia torque TI of the engine E and the torque converter 12 is maximized at a time half of the calculated target engagement time (target ON time) or in the vicinity thereof. Since the transmission torque TLC of the lockup clutch LC is calculated (S16, S500 to S508, S600 to S606, S700 to S708), in addition to the above-described effects, it is possible to more reliably prevent the above-described shock from occurring. Can do.

  In the above description, the present invention has been described by taking a parallel shaft type automatic transmission as an example, but 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 (2)

  A target for calculating a target slip amount of the lockup clutch in accordance with a predetermined characteristic in a control device for an automatic transmission that inputs and outputs an output of an engine mounted on a vehicle via a torque converter having a lockup clutch A slip amount calculating means; an engine speed reduction amount calculating means for calculating a reduction amount of the engine speed necessary to absorb the calculated target slip amount; and the calculated in accordance with a predetermined characteristic. A target engagement time calculating means for calculating a target engagement time of the lockup clutch from an amount of decrease in the engine speed; and an inertia torque of the engine and the torque converter is maximized during the calculated target engagement time. The transmission torque calculating means for calculating the transmission torque of the lockup clutch, and the calculation And an oil pressure control means for calculating a hydraulic pressure to be supplied to the lockup clutch so as to obtain the transmitted torque and calculating a hydraulic pressure control value so as to obtain the calculated hydraulic pressure. Machine control device.   The transmission torque calculation means calculates the transmission torque of the lockup clutch so that the inertia torque of the engine and the torque converter becomes maximum at a time that is 1/2 of the calculated target engagement time or a time in the vicinity thereof. The control device for an automatic transmission according to claim 1.

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