JP6038755B2 - Control device for lock-up clutch - Google Patents

Description

  The present invention relates to a control device for a lockup clutch.

  The lock-up clutch of the torque converter is based on the map characteristics that can be searched based on the vehicle speed and the driver's required driving force for the drive source, the direct connection position that directly connects the pump impeller and the turbine runner, and the release position that releases them. However, if the slip position is controlled for a long time, the temperature of the friction material of the lockup clutch increases, and if left unattended, the durability deteriorates. As described in No. 1, protection control for preventing the friction material from being heated has been proposed.

  In the protection control described in Patent Document 1, the transmission torque of the lockup clutch is obtained from the engine torque, and the heat generation amount of the friction material is calculated from the obtained transmission torque of the lockup clutch, the slip amount, and the slip time. When the calculated value exceeds the predetermined value as compared with the predetermined value, the lockup clutch is controlled to the direct coupling position or the disengaged position according to the degree of the accelerator opening (the driver's required driving force).

JP 2011-149484 A

  By performing the protection control as proposed in Patent Document 1, it is possible to prevent a decrease in the durability of the lockup clutch. As a result, when the protection control is required, the normal control based on the map characteristics is performed during traveling. As soon as the protection control is switched, the control is immediately switched to the normal control when the protection control is completed. On the other hand, if the switch to protection control is delayed, the durability of the lockup clutch may be reduced.

  Accordingly, the object of the present invention is to solve the above-described problems and perform normal control of the lockup clutch based on map characteristics set so as to be searchable from the vehicle speed or the like, while based on a parameter indicating the load state of the friction material. Of the lock-up clutch that optimally achieves both the prevention of a decrease in the durability of the lock-up clutch and the prevention of a decrease in drivability by smoothly switching between the normal control and the protection control. It is to provide a control device.

  In order to solve the above-described problems, in claim 1, a pump impeller coupled to a drive source mounted on a vehicle, a turbine runner coupled to a transmission, and the pump impeller and turbine runner can be directly coupled. A torque converter having a lock-up clutch, and a direct connection position for directly connecting the pump impeller and the turbine runner based on map characteristics set so as to be searchable from a vehicle speed of the vehicle and a driver's required driving force with respect to the drive source; In a control apparatus for a lockup clutch, comprising: a release position for releasing them; and a control means for controlling the lockup clutch so as to be any one of a slip position between the direct connection position and the release position. Parameter calculating means for calculating a parameter indicating a load state of the friction material, and the parameter A comparison unit that compares the parameter calculated by the output unit with a first threshold value and a second threshold value that are set in consideration of the degree of lightness of the decrease in durability of the lockup clutch, and the control unit includes: When it is determined that the calculated parameter is greater than or equal to the first threshold and less than the second threshold, the lockup clutch is controlled based on the map characteristics and the lockup clutch is switched to the released position. When the first protection control for prohibiting switching to the direct connection position or the slip position is executed, and when the calculated parameter is determined to be equal to or greater than the second threshold value, the lockup clutch is immediately set to the release position. Thereafter, the direct connection position or the solution is changed until the calculated parameter becomes less than the first threshold value. And as configured to perform a second protection control to prohibit switching to position.

  In the lockup clutch control device according to claim 2, the control means may be configured such that, in the first protection control, the lockup clutch is controlled by control based on the map characteristics or by a predetermined operation by a driver. After switching to the release position, switching to the direct connection position or slip position is prohibited until the calculated parameter becomes less than the first threshold value.

  4. The lockup clutch control apparatus according to claim 3, wherein the control means is a required drive in which the required driving force of the driver is changed after the calculated parameter has decreased to less than the first threshold value. It is determined whether or not it is in the force change state, and when it is determined that the required drive force change state is established, the control is returned from the first protection control or the second protection control to the control based on the map characteristics.

  In the lockup clutch control device according to the first aspect, the parameter indicating the load state of the friction material of the lockup clutch is calculated, and the calculated parameter is used to determine the degree of lightness of the decrease in the durability of the lockup clutch. The first threshold value and the second threshold value set in consideration are compared, and when the calculated parameter is determined to be greater than or equal to the first threshold value and less than the second threshold value, the driver's requested drive for the vehicle speed and the drive source The first protection control for continuing the control of the lockup clutch based on the map characteristics set so as to be searchable from the force and prohibiting the switching to the direct connection position or the slip position when the lockup clutch is switched to the release position. If the calculated parameter is determined to be greater than or equal to the second threshold, the lockup clutch is immediately switched to the released position. Thereafter, since the second protection control for prohibiting switching to the direct connection position or the release position is executed until the calculated parameter becomes less than the first threshold value, the normal control and the protection control are smoothly performed. Therefore, it is possible to optimally achieve both the prevention of a decrease in durability of the lockup clutch and the prevention of a decrease in drivability.

  That is, the calculated parameter is compared with the first threshold value and the second threshold value that are set in consideration of the lightness of the decrease in the durability of the lockup clutch, and the calculated parameter is equal to or higher than the first threshold value. When it is determined that it is less than 2 threshold values, the degree of decrease in durability is relatively light. Therefore, control of the lockup clutch based on the map characteristics is continued, and when it is determined that it is equal to or more than the second threshold value, the degree of decrease is Since it is heavy, immediately switching to the release position makes it possible to optimally achieve both prevention of a decrease in durability of the lockup clutch and prevention of a decrease in drivability.

  Further, when the calculated parameter is determined to be greater than or equal to the first threshold value and less than the second threshold value, the control of the lockup clutch based on the map characteristics is continued, and the direct connection position when the lockup clutch is switched to the release position. Alternatively, the first protection control that prohibits switching to the slip position is executed, and if it is determined to be greater than or equal to the second threshold value, the lockup clutch is immediately switched to the release position, and thereafter the calculated parameter is less than the first threshold value. By executing the second protection control that prohibits switching to the direct connection position or the release position until the time becomes, normal control and the first and second protection controls can be smoothly switched.

  In the lockup clutch control device according to claim 2, in the first protection control, a predetermined operation by the driver, for example, a panic brake operation of the brake pedal, an accelerator pedal kickdown, or the like, is performed based on the map characteristics. When the lockup clutch is switched to the disengaged position by operation, switching from on to off, or range switching operation by the range selector, thereafter, the direct connection position or slip position is reached until the calculated parameter falls below the first threshold. Therefore, in addition to the above-described effects, the normal control and the first protection control can be smoothly switched.

  In the lockup clutch control device according to claim 3, whether or not the driver's required driving force is changed after the calculated parameter is reduced to less than the first threshold value. When the determination is made and it is determined that the required driving force change state is established, the first protection control or the second protection control is configured to return to the control based on the map characteristics. By performing it when it is difficult, it is possible to more smoothly switch from the first and second protection controls to the normal control.

It is the schematic which shows the control apparatus of the lockup clutch which concerns on this invention generally. FIG. 2 is a hydraulic circuit diagram of a transmission hydraulic pressure supply mechanism of the apparatus shown in FIG. 1. It is a flowchart which shows operation | movement of the apparatus shown in FIG. Similarly, it is a block diagram which shows operation | movement of the apparatus shown in FIG. 3 is an explanatory diagram showing the characteristics (map characteristics) of LCMAP used in the processing of the flow chart. It is a block diagram which shows the process of LC calorific value calculation block of FIG. 4 in detail. It is a time chart which shows an example of a time-dependent change of the temperature of the friction material of the lockup clutch shown in FIG. FIG. 8 is a sequence diagram for explaining the relationship between the increase in the friction material temperature shown in FIG. 7 and the first and second protection controls. FIG. 4 is a flowchart showing a return process from the first (or second) protection control to the normal control executed in the flowchart of FIG. 3.

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

  FIG. 1 is a schematic view showing a lockup clutch control apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 10 denotes an engine (internal combustion engine, drive source). The engine 10 is mounted on a vehicle 14 provided with drive wheels 12 (the vehicle 14 is partially indicated by the engine 10, the drive wheels 12 and the like).

  The throttle valve 16 disposed in the intake system of the engine 10 is disconnected from the accelerator pedal 18 disposed on the floor surface of the vehicle driver's seat and the DBW (Drive By Wire) mechanism 20 including an actuator such as an electric motor is disconnected. And is opened and closed by the DBW mechanism 20.

  The intake air metered by the throttle valve 16 flows through an intake manifold (not shown) and mixes with fuel injected from an injector (not shown) in the vicinity of the intake port of each cylinder to form an air-fuel mixture. When an intake valve (not shown) is opened, it flows into a combustion chamber (not shown) of the cylinder. The air-fuel mixture is ignited and combusted in the combustion chamber, and after driving the piston and rotating the crankshaft (not shown), it is discharged to the outside of the engine 10 as exhaust.

  The rotation of the crankshaft is input to the automatic transmission (transmission) 24 via the output shaft 10a and the torque converter 22. The automatic transmission 24 includes a continuously variable transmission (hereinafter referred to as “CVT”) 26.

  The torque converter 22 is connected to the engine 10 via the cover member 22a including the drive plate connected to the output shaft 10a of the engine 10 and the cover member 22a, in other words, the cover member 22a and the output shaft 10a. The pump impeller 22b and the pump impeller 22b are arranged opposite to the pump impeller 22b and supplied with hydraulic oil ATF, and are connected to the main shaft (transmission input shaft) MS, in other words, the automatic transmission 24 via the main shaft MS. A turbine runner 22c connected to the pump runner 22c, and a pump-up impeller 22b and a lock-up clutch 22d that can directly connect the turbine runner 22c.

  The lockup clutch 22d includes a piston 22d1, and a back pressure chamber 22d2 (shown in FIG. 2) is formed between the piston 22d1 and the inside of the cover member 22a. A plate-like friction material (facing) 22d3 is affixed to the piston 22d1, and is configured to increase the fastening force when the piston 22d1 is pressed inside the cover member 22a.

  The CVT 26 is a main shaft MS, more precisely, a drive (DR) pulley 26a disposed on the outer shaft, a counter shaft (transmission output shaft) CS parallel to the main shaft MS, and more precisely, an outer shaft thereof. And a power transmission member, for example, a metal belt 26c, hung around the driven (DN) pulley 26b.

  The drive pulley 26a is fixed to the stationary pulley half 26a1 which is disposed so as not to be rotatable relative to the outer peripheral shaft of the main shaft MS and is not movable in the axial direction, and to the fixed pulley half 26a1 which is not rotatable relative to the outer peripheral shaft of the main shaft MS. A movable pulley half 26a2 that is relatively movable in the axial direction, and a movable pulley half 26a2 that is provided on the side of the movable pulley half 26a2 and is supplied with hydraulic pressure (hydraulic oil pressure). A hydraulic actuator 26a3 composed of a piston, a cylinder and a spring is provided to press the body 26a1.

  The driven pulley 26b includes a fixed pulley half 26b1 that is not rotatable relative to the outer peripheral shaft of the counter shaft CS and is not movable in the axial direction, and an axial direction relative to the fixed pulley half 26b1 that is not rotatable relative to the counter shaft CS. A movable pulley half 26b2 that is relatively movable, and a piston that is provided on the side of the movable pulley half 26b2 and presses the movable pulley half 26b2 toward the fixed pulley half 26b1 when hydraulic pressure is supplied. A hydraulic actuator 26b3 including a cylinder and a spring is provided.

  In the automatic transmission 24, the CVT 26 is connected to the engine 10 via the forward / reverse switching mechanism 28. The forward / reverse switching mechanism 28 includes a forward clutch 28a that allows the vehicle 14 to travel in the forward direction, a reverse brake clutch 28b that allows the vehicle 14 to travel in the reverse direction, and a planetary gear mechanism 28c disposed therebetween. . The CVT 26 is connected to the engine 10 via a forward clutch 28a (and a reverse brake clutch 28b).

  In the planetary gear mechanism 28c, the sun gear 28c1 is fixed to the main shaft MS, and the ring gear 28c2 is fixed to the fixed pulley half 26a1 of the drive pulley 26a via the forward clutch 28a.

  A pinion 28c3 is disposed between the sun gear 28c1 and the ring gear 28c2. Pinion 28c3 is connected to sun gear 28c1 by carrier 28c4. When the reverse brake clutch 28b is operated, the carrier 28c4 is fixed (locked) thereby.

  The rotation of the countershaft CS is transmitted from the secondary shaft (intermediate shaft) SS to the drive wheels 12 via a gear. That is, the rotation of the countershaft CS is transmitted to the secondary shaft SS via the gears 30a and 30b, and the rotation is transmitted from the differential 32 to the left and right drive wheels (only the right side is shown) 12 via the gear 30c.

  A disc brake 34 is disposed in the vicinity of the driving wheel (front wheel) 12 and a driven wheel (rear wheel, not shown), and a brake pedal 36 is disposed on the vehicle driver's seat floor. The brake pedal 36 is connected to the disc brake 34 via a master back 38 and a master cylinder 40. When the driver depresses the brake pedal 36, the depressing force is increased by the master back 38 and transmitted from the master cylinder 40 to the disc brake 34, and the disc brake 34 is operated to brake (decelerate) the vehicle 14.

  In the forward / reverse switching mechanism 28, the forward clutch 28a and the reverse brake clutch 28b are switched by the driver operating a range selector 44 provided in the vehicle driver's seat to select one of the ranges such as P, R, N, and D. It is done by selecting. The range selection by the driver's operation of the range selector 44 is transmitted to the manual valve of the transmission hydraulic pressure supply mechanism 46, and the vehicle 14 travels forward or backward.

  In this specification, the automatic transmission 24 includes a torque converter 22, a CVT 26, and a forward / reverse switching mechanism 28 (more specifically, its forward clutch 28a and reverse brake clutch 28b).

  FIG. 2 is a hydraulic circuit diagram of the transmission hydraulic pressure supply mechanism 46.

  As shown, the transmission hydraulic pressure supply mechanism 46 is provided with a hydraulic pump (oil feed pump) 46a. The hydraulic pump 46a is a gear pump, is driven by the engine (denoted “E”) 10, pumps up hydraulic oil stored in the reservoir 46b, and pumps it to a PH control valve (PH REG VLV) 46c.

  On the other hand, the output of the PH control valve 46c (PH pressure (line pressure). High pressure control hydraulic pressure) is supplied from the oil passage 46d through the first and second regulator valves (DR REG VLV, DN REG VLV) 46e, 46f. Connected to the piston chamber (DR) 26a31 of the hydraulic actuator 26a3 of the drive pulley 26a and the piston chamber (DN) 26b31 of the hydraulic actuator 26b3 of the driven pulley 26b, and on the other hand, the CR valve (CR VLV) 46h via the oil passage 46g. Connected to.

  The CR valve 46h reduces the PH pressure to generate CR pressure (low pressure control hydraulic pressure), and the first, second, and third linear solenoid valves (LS-DR, LS-DN, LS-CPC, electromagnetic) from the oil passage 46i. Valve) 46j, 46k, 46l.

  The first and second linear solenoid valves 46j and 46k act on the first and second regulator valves 46e and 46f with the output pressure determined according to the excitation of the solenoids, and thus the operation of the PH pressure sent from the oil passage 46d. Oil is supplied to the piston chambers 26a31 and 26b31 of the hydraulic actuators 26a3 and 26b3.

  As a result, a pulley side pressure (narrow pressure) is generated by moving the movable pulley halves 26a2 and 26b2 in the axial direction to narrow the belt 26c, and the pulley widths of the drive pulley 26a and the driven pulley 26b are changed. The winding radius changes. Thus, by adjusting the side pressures of the pulleys 26a and 26b, the ratio (transmission ratio) for transmitting the output of the engine 10 to the drive wheels 12 can be changed steplessly.

  The output (CR pressure) of the CR valve 46h is adjusted according to the excitation of the solenoid of the third linear solenoid valve 46l, and sent to the manual valve (MAN VLV, indicated by reference numeral 46o) through the oil passage 46m. From there, they are connected to the piston chamber (FWD) 28a1 of the forward clutch 28a of the forward / reverse switching mechanism 28 and the piston chamber (RVS) 28b1 of the reverse brake clutch 28b.

  As described above, the manual valve 46o outputs the output regulated by the third linear solenoid valve 46l in accordance with the position of the range selector 44 operated (selected) by the driver, as described above, in the piston chambers of the forward clutch 28a and the reverse brake clutch 28b. 28a1 and 28b1 are connected.

  The output of the PH control valve 46c is sent to the TC regulator valve (TC REG VLV) 46q via the oil passage 46p, and the output of the TC regulator valve 46q is LC shifted via the LC control valve (LC CTL VLV) 46r. Connected to valve (LC SFT VLV) 46s.

  The output of the LC shift valve 46s is connected to a back pressure chamber 22d2 formed between the piston 22d1 of the lockup clutch 22d of the torque converter 22 and the inside of the cover member 22a via an oil passage 46t.

  The output of the CR valve 46h is connected to an LC control valve 46r and an LC shift valve 46s through an oil passage 46u, and a fourth linear solenoid valve (LS-LC; electromagnetic valve) 46v is inserted in the oil passage 46u. . The LC shift valve 46s is connected to an on / off solenoid valve (SOL, normally open electromagnetic valve) 46w.

  The case where the lockup clutch 22d is first released will be described. In this case, both the fourth linear solenoid valve 46v and the on / off solenoid valve 46w are demagnetized. As a result, the output of the fourth linear solenoid valve 46v becomes zero, while the output does not change because the on / off solenoid valve 46w is a normally open type.

  Accordingly, the hydraulic oil is sent from the LC shift valve 46s through the oil passage 46t to the back pressure chamber 22d2, and is discharged from the oil passage 46x through the LC shift valve 46s through the pump impeller 22b and the turbine runner 22c. Accordingly, the piston 22d1 is separated from the cover member 22a, and the lockup clutch 22d is released (controlled to a release position for releasing the pump impeller 22b and the turbine runner 22c).

  Next, the case where the lockup clutch 22d is engaged will be described. In this case, both the fourth linear solenoid valve 46v and the on / off solenoid valve 46w are excited. As a result, the hydraulic oil introduced into the back pressure chamber 22d2 flows from the oil passage 46t through the LC shift valve 46s to the LC control valve 46r and is discharged from the discharge port.

  Accordingly, the piston 22d1 is pressed by the cover member 22a, and the lockup clutch 22d is fastened (engaged) (controlled to a direct connection position where the pump impeller 22b and the turbine runner 22c are directly connected).

  At this time, the output (LCC pressure) is made different according to the command value (energization command value) LCCCMD of the fourth linear solenoid valve 46v, thereby adjusting the position of the spool of the LC control valve 46r, and an amount corresponding to it. By discharging the hydraulic oil from the back pressure chamber 22d2, the degree of engagement (slip amount) of the lockup clutch 22d is adjusted (controlled to a slip position between the direct connection position and the release position).

  Returning to the description of FIG. 1, a crank angle sensor 50 is provided at an appropriate position such as near the cam shaft (not shown) of the engine 10 and outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. To do. In the intake system, an absolute pressure sensor 52 is provided at an appropriate position downstream of the throttle valve 16 and outputs a signal proportional to the intake pipe absolute pressure (engine load) PBA.

  The actuator of the DBW mechanism 20 is provided with a throttle opening sensor 54 and outputs a signal proportional to the opening TH of the throttle valve 16 through the rotation amount of the actuator.

  Further, an accelerator opening sensor 56 is provided in the vicinity of the accelerator pedal 18, and a signal proportional to the accelerator opening AP corresponding to the driver's accelerator pedal operation amount (the driver's required driving force for the engine 10) is provided. Output. A brake switch 58 is provided in the vicinity of the brake pedal 36, and outputs an ON signal when the brake pedal 36 is operated by the driver. The output of the crank angle sensor 50 and the like described above is sent to the engine controller 66.

  The main shaft MS is provided with an NT sensor (rotational speed sensor) 70, and the rotational speed of the turbine runner 22c (turbine rotational speed) NT, specifically, the rotational speed of the main shaft MS (transmission input shaft rotational speed). More specifically, a pulse signal corresponding to the input shaft speed of the forward clutch 28a is output.

  An NDR sensor (rotational speed sensor) 72 is provided at an appropriate position in the vicinity of the drive pulley 26a of the CVT 26 to output a pulse signal corresponding to the rotational speed NDR of the drive pulley 26a, in other words, the output shaft rotational speed of the forward clutch 28a. To do.

  An NDN sensor (rotational speed sensor) 74 is provided at an appropriate position in the vicinity of the driven pulley 26b to output a pulse signal corresponding to the rotational speed NDN of the driven pulley 26b (the rotational speed of the countershaft CS), and the secondary shaft SS. A V sensor (rotational speed sensor) 76 is provided in the vicinity of the gear 30b and outputs a pulse signal corresponding to the vehicle speed V through the rotation of the secondary shaft SS.

  A range selector switch 80 is provided in the vicinity of the above-described range selector 44 and outputs a signal corresponding to a range such as P, R, N, D selected by the driver.

  As shown in FIG. 2, a hydraulic pressure supplied to the piston chamber 26b31 of the hydraulic actuator 26b3 of the driven pulley 26b is disposed in the oil passage leading to the driven pulley 26b of the CVT 26 in the transmission hydraulic pressure supply mechanism 46. Output a signal according to.

  A second pressure sensor 82b is disposed in the oil passage between the piston chamber 28a1 of the forward clutch 28a and the manual valve 46o, and outputs a signal corresponding to the hydraulic pressure supplied to the piston chamber 28a1 of the forward clutch 28a. A third pressure sensor 82c is disposed in the oil passage 46t that communicates with the back pressure chamber 22d2 of the lockup clutch 22d of the torque converter 22 and outputs a signal corresponding to the hydraulic pressure supplied to that portion.

  Further, an oil temperature sensor 84 is disposed in the reservoir 46b and outputs a signal corresponding to the oil temperature (temperature TATF of the hydraulic oil ATF).

  Returning to the description of FIG. 1 again, the output of the NT sensor 70 and the like described above is sent to the shift controller 90 including the outputs of other sensors (not shown). The engine controller 66 and the shift controller 90 each include a microcomputer composed of a CPU, ROM, RAM, I / O, and the like, and are configured to be able to communicate with each other.

  Based on the sensor output described above, the engine controller 66 determines the target throttle opening from the detected accelerator opening and the like to control the operation of the DBW mechanism 20, and determines the fuel injection amount and ignition timing to determine the injector or ignition plug. The operation of the engine 10 is controlled through an ignition device.

  The shift controller 90 excites and demagnetizes the first to fourth linear solenoid valves 46j, 46k, 46l, 46v and the on / off solenoid valve 46w of the transmission hydraulic pressure supply mechanism 46 based on the sensor output described above. Then, the operation of the forward / reverse switching mechanism 28 and the torque converter 22 is controlled, and the operation of the CVT 26 is controlled by controlling the pulley supply hydraulic pressure (side pressure).

  Further, the shift controller 90 executes protection control for the lock-up clutch 22d of the torque converter 22.

  FIG. 3 is a flowchart showing the operation of the shift controller 90, that is, the operation of the lockup clutch control device according to this embodiment, and FIG. 4 is a block diagram showing the operation in the same manner.

  Referring mainly to the flowchart of FIG. 3, LCMAP that means a map (MAP) indicating the control contents of the lockup clutch (LC) 22d is referred to in S10 (S: processing step).

  FIG. 5 is an explanatory diagram showing LCMAP characteristics (map characteristics).

  As shown in the figure, LCMAP is set so as to be searchable from the vehicle speed V of the vehicle 14 detected by the V sensor 76 and the accelerator opening AP (the driver's requested driving force for the engine 10) detected from the accelerator opening sensor 56. Is done.

  More specifically, the LCMAP is based on the running state of the vehicle 14 defined by the vehicle speed V and the accelerator opening (the driver's requested driving force for the engine 10) AP, and the LC tight region is controlled by the lockup clutch 22d. (Control to a direct connection position where the pump impeller 22b and the turbine runner 22c are directly connected), release region (control to a release position where the pump impeller 22b and the turbine runner 22c are completely released), slip between the LC tight region and the release region It is determined whether it is in one of the three areas (controlling to a slip position between the direct connection position and the release position), and control is set so as to select the control according to it.

  In the flowchart of FIG. 3, the process then proceeds to S12 to determine whether or not the lockup clutch 22d should be engaged. When it is determined that the vehicle is in the disengagement region from the vehicle speed V and the accelerator pedal opening AP detected in the process of S10, the determination of S12 is denied and the process proceeds to S14, and the LC is released, that is, the lockup clutch 22d is set to the disengaged position. Control.

  On the other hand, when it is determined in the process of S10 that the current position is in the LC tight or slip region, the determination in S12 is affirmed and the process proceeds to S16, and the LC engagement, that is, the lockup clutch 22d is controlled to the direct connection position or the slip position.

  Next, in S18, the command value-based LC transmission torque is calculated. That is, the first estimated value of the transmission torque of the lockup clutch 22d based on at least a command value given to the electromagnetic control valves (the fourth linear solenoid valve 46v and the on / off solenoid valve 46w, particularly the fourth linear solenoid valve 46v). Is calculated.

  Referring to the block diagram of FIG. 4, the shift controller 90 includes a command value-based LC transmission torque calculation block (first estimated value calculation means) 90a, and the calculation block 90a is provided to at least the fourth linear solenoid valve 46v. Based on the command value LCCCMD and the oil temperature (temperature TATF of the hydraulic oil ATF) detected from the oil temperature sensor 84, the command value-based LC transmission torque (first estimated value of the transmission torque) is calculated according to appropriate characteristics.

  Returning to the description of the flow chart of FIG. 3, the process then proceeds to S20 to calculate the estimated torque-based LC transmission torque. That is, the second estimated value of the transmission torque of the lockup clutch 22d is calculated based on at least the output torque (engine torque) of the engine 10 mounted on the vehicle 14 and the engine speed NE.

  Referring to the block diagram of FIG. 4, as shown in the figure, the shift controller 90 includes an estimated torque base LC transmission torque calculation block (second estimated value calculation means) 90b. The calculation block 90b includes engine (ENG) torque Ten and Based on the engine speed NE and the like, an estimated torque-based LC transmission torque (second estimated value of the transmission torque) is calculated according to appropriate characteristics.

  More specifically, the calculation block 90b calculates the torque to a search value obtained by searching an appropriate characteristic from the engine speed NE detected from the crank angle sensor 50 and the intake pipe absolute pressure PBA detected from the absolute pressure sensor 52. The engine torque is calculated by multiplying the amplification factor of the converter 22.

The calculation block 90b includes a torque converter transmission torque calculation block 90b1, and the calculation block 90b1 calculates torque converter transmission torque Ttc (torque transmitted by the torque converter 22) according to the following equation simultaneously with the calculation of the calculation block 90b.
Ttc = τe × (NE / 1000) ²
In the above, τe is a pump capacity coefficient, and is calculated by searching a searchable map from the slip ratio e of the torque converter 22, the engine speed NE, and the oil temperature TATF. Note that the slip ratio e of the torque converter 22 is obtained by the turbine rotational speed NT / the engine rotational speed NE.

Next, the calculation block 90b calculates an estimated torque-based LC transmission torque Tlc by subtracting the torque converter transmission torque Ttc from the calculated engine torque Ten. That is, the torque input from the engine 10 to the torque converter 22 is expressed by the following equation.
Ten-Ttc-Tlc-Ien = 0
In the formula, Ien represents engine inertia. From the above equation, the estimated torque-based transmission torque can be calculated from the engine torque Ten, the torque converter transmission torque Ttc, and the engine inertia.

  Returning to the description of the flow chart of FIG. 3, the process then proceeds to S22, where the command value-based LC transmission torque calculated in S18 is compared with the estimated torque-based LC transmission torque calculated in S20, and min, That is, the minimum value (more specifically, the smaller value) is selected. This process corresponds to the process of the LC transmission torque min selection block 90c in the block diagram of FIG.

  Next, in S24, the LC heat generation amount, that is, the heat generation amount of the friction material 22d3 of the lockup clutch 22d (a parameter indicating the load state of the friction material 22d3) is calculated based on the selected minimum value. This process corresponds to the process of the LC heat generation amount calculation block 90d in the block diagram of FIG.

  FIG. 6 is a block diagram showing in detail the processing of the LC calorific value calculation block 90d of FIG.

  As will be described below, the LC heat generation amount calculation block 90d includes a friction material heat generation amount calculation block 90d1, and the calculation block 90d1 is the minimum of the LC transmission torque selected by the selection block 90c, that is, the minimum value, the oil temperature TATF, and the engine rotation. Based on the number NE and the turbine speed NT, the friction material heat generation amount (the heat generation amount [J] of the friction material 22d3 of the lockup clutch 22d) is calculated.

  The LC heat generation amount calculation block 90d includes a torque converter estimated temperature calculation block 90d2 and a friction material temperature calculation block 90d3. The calculation block 90d2 is based on the engine coolant temperature TW, the oil temperature TATF, and the engine speed NE, and is converted into a torque converter. The estimated temperature [° C.] within 22 is calculated.

  The calculation block 90d3 converts the friction material heat generation amount calculated in the calculation block 90d1 into a temperature by an appropriate conversion method, and divides the estimated temperature in the torque converter calculated in the calculation block 90d2 from the converted value to calculate the friction material temperature [° C. ] And outputs the calculated value.

  Returning to the description of the flow chart of FIG. 3, the process then proceeds to S26 and the subsequent steps, and based on the selected value, more specifically, the selected minimum value, the amount of heat generated by the friction material 22d3 of the lockup clutch 22d (load state is changed). And a protection control for preventing the temperature of the friction material 22d3 from rising based on the calculated heat generation amount. This process corresponds to the process of the LC protection control determination block 90e in the block diagram of FIG.

  As shown in FIG. 4, the shift controller 90 includes an estimated LC torque application determination block 90f. The determination block 90f includes at least the engine rotational speed (the rotational speed of the engine 10) NE and the turbine rotational speed (the rotational speed of the turbine runner 22c). ) Based on NT, more specifically, based on the slip rate e of the lockup clutch 22d calculated from them, the estimated torque-based LC transmission torque calculation by the estimated torque-based LC transmission torque calculation block 90b is in a reliable operating state. Judgment (determination) is made.

  More specifically, the determination block 90f indicates that the slip ratio e of the lockup clutch 22d is not less than a predetermined value (for example, 95%) during deceleration, the lockup clutch 22d is engaged (95 to 105%), or the vehicle 14 Is in a deceleration slip (105% or more), it is not determined that the estimated torque-based LC transmission torque of the torque converter 22 is in a reliable operating state, and the contact of the switch 90f1 is switched from 90f11 to 90f12. Then, protection control is executed based on the command value-based transmission torque calculated by the command value-based LC transmission torque calculation block 90a.

  The determination block 90f can reliably calculate the estimated torque-based LC transmission torque by the estimated torque-based LC transmission torque calculation block 90b based on the accelerator opening AP, engine torque calculation failure information, and the like in addition to the above parameters. It is determined whether or not the vehicle is in a proper operating state.

  Returning to the description of the flow chart in FIG. 3, the process then proceeds to S26, where the calculated LC heat generation amount, more specifically, the friction material temperature calculated in the calculation block 90d3 of FIG. 6 is compared with the first threshold value. It is determined whether the friction material temperature is equal to or higher than a first threshold value.

  When the result in S26 is negative, the subsequent processing is skipped. When the result is positive, the process proceeds to S28, where it is determined whether the calculated friction material temperature is equal to or higher than the second threshold value. When it is determined that the threshold value is greater than or equal to the threshold value and less than the second threshold value, the process proceeds to S30, and the first protection control is executed. To do.

  FIG. 7 is a time chart showing an example of a change over time of the temperature of the friction material 22d3 of the lockup clutch 22d shown in FIG.

  As shown in the figure, the first threshold value corresponding to the first protection control is set to a low value, while the second threshold value corresponding to the second protection control is set to a value higher than the first threshold value. That is, the first and second threshold values consider the degree of lightness of the decrease in durability of the lockup clutch 22d, and the first threshold value increases to such a degree that the temperature of the friction material 22d3 slightly deteriorates the durability of the lockup clutch 22d. The second threshold value is set to a level at which it can be detected that the temperature has risen to a level that significantly deteriorates the durability.

  FIG. 8 is a sequence diagram for explaining the relationship between the increase in the friction material temperature and the first and second protection controls.

  FIG. 8A is a description of the first protection control. In the following description, when normal control based on the LCMAP characteristic, which is not the first (second) protection control of the lockup clutch 22d, is executed, the friction material. Normally, the temperature gradually increases, but the first protection control is not executed as long as it is determined to be less than the first threshold in the process of S26 of the flow chart of FIG.

  However, the increase in the friction material temperature continues to be high, and it is determined in S26 that the friction material temperature is equal to or higher than the first threshold value, and is affirmed. However, as long as it is less than the second threshold value, the normal control of the lockup clutch 22d based on the LCMAP characteristic is continued as it is, and in the normal control based on the LCMAP characteristic or by a predetermined operation by the driver, Is switched to the release position (when LC is turned off), thereafter, the first protection control for prohibiting switching to the direct connection position or the slip position (LC engagement prohibition) is executed.

  Here, the predetermined operation by the driver means, for example, a case where a panic brake operation of the brake pedal 36, a kick-down operation of the accelerator pedal 18, a switching operation from on to off, or a range switching operation by the range selector 44 is performed. To do.

  FIG. 8B is a description of the second protection control. In the following description, when the friction material temperature rises beyond the first threshold and becomes extremely high, an LC protection control operation request is made.

  The processing of the flow chart of FIG. 3 is when the friction material temperature is determined to be greater than or equal to the second threshold value in S28 and the process proceeds to S32. In this case, even if the vehicle 14 is traveling, the lockup clutch 22d is immediately switched to the release position, and thereafter, the second protection control for prohibiting switching to the direct connection position or the slip position (LC fastening prohibition) is executed.

  As shown in FIGS. 8 (a) and 8 (b), when the temperature of the friction material subsequently decreases and becomes a temperature lower than the first threshold (negative in S26 of FIG. 3), the first protection control is performed. To normal control based on the LCMAP characteristic, and slip control is also executed as necessary. Therefore, “after” means until the friction material temperature becomes less than the first threshold value.

  FIG. 9 is a flowchart showing a return process from the first (or second) protection control to the normal control executed in the flowchart of FIG.

  As will be described below, in S100, the LC heat generation amount is calculated in the same manner as in the process of S24 in the flow chart of FIG. 3, and the process proceeds to S102 to determine whether or not the friction material temperature has decreased, more specifically, below the first threshold value. to decide.

  When the result in S102 is negative, the subsequent processing is skipped, while when the result is affirmative, the process proceeds to S104. When the vehicle driving force of the vehicle 14 is switched, in other words, the required driving force in which the driver's required driving force is changed. It is determined whether or not there is a change state.

  When the result in S104 is affirmative and it is determined that the requested driving force is changed, the process proceeds to S106, and the normal control (control of the operation of the lockup clutch 22d based on the LCMAP characteristics) is returned from the first or second protection control. When the result in S104 is negative, the program proceeds to S108, and the first or second protection control is continued. Thereby, it is possible to return to the normal control from the first or second protection control without giving the driver a sense of incongruity.

  As described above, in this embodiment, the pump impeller 22b connected to the drive source (engine) 10 mounted on the vehicle 14, the turbine runner 22c connected to the transmission (automatic transmission) 24, and the pump. The torque converter 22 having a lock-up clutch 22d that can directly connect the impeller and the turbine runner, and the vehicle speed V of the vehicle and the driver's required driving force (accelerator opening AP) for the driving source are set so as to be searchable. Based on a map (LCMAP) characteristic, the lock-up clutch 22d is either directly connected to the pump impeller and the turbine runner, or to a release position to release them, or to a slip position between the direct connection position and the release position. Control device for lockup clutch provided with control means (shift controller 90) for controlling The parameter calculation means (LC heat generation amount calculation unit 90d, S24) for calculating the parameter (friction material heat generation amount) indicating the load state of the friction material 22d3 of the lockup clutch 22d, and the parameter calculation means. Comparing means (S26, S28) for comparing the parameter with a first threshold value and a second threshold value that are set in consideration of the degree of lightness of the decrease in durability of the lockup clutch, and the control means, When it is determined that the calculated parameter is greater than or equal to the first threshold value and less than the second threshold value, the control of the lockup clutch based on the map characteristic is continued and the lockup clutch is switched to the release position. Executes first protection control for prohibiting switching to the direct connection position or slip position (S30). If the calculated parameter is determined to be greater than or equal to the second threshold, the lockup clutch is immediately switched to the disengaged position, and thereafter, the direct connection position until the calculated parameter is less than the first threshold. Alternatively, since the second protection control for prohibiting switching to the release position is executed (S32), the normal control and the protection control can be smoothly switched to prevent the durability of the lockup clutch 22d from being lowered. And the prevention of a decrease in drivability can be optimally achieved.

  That is, the calculated parameter (the amount of heat generated by the friction material) is compared with the first threshold value and the second threshold value, which are set in consideration of the degree of reduction in durability of the lockup clutch 22d, and the calculated parameter Is determined to be greater than or equal to the first threshold value and less than the second threshold value, the degree of decrease in durability is relatively light. Therefore, the control of the lockup clutch 22d based on the map (LCMAP) characteristics is continued and the second threshold value is maintained. If it is determined as above, since the degree of reduction is heavy, immediately switching to the release position can optimally achieve both prevention of the durability of the lockup clutch 22d and prevention of reduction of drivability. .

  When it is determined that the calculated parameter is greater than or equal to the first threshold value and less than the second threshold value, the control of the lockup clutch 22d based on the map characteristics is continued and the lockup clutch 22d is switched to the released position. While the first protection control for prohibiting switching to the direct connection position or the slip position is executed, when it is determined that the second threshold value or more is reached, the lockup clutch 22d is immediately switched to the disengagement position, and thereafter, the calculated parameter is changed to the first parameter. By executing the second protection control that prohibits switching to the direct connection position or the release position until the threshold value is less than one threshold value, it is possible to smoothly switch between the normal control and the first and second protection controls.

  In the first protection control, the control means may be a control based on the map (LCMAP) characteristic or a predetermined operation by the driver, for example, a panic brake operation of the brake pedal 36, a kick-down operation of the accelerator pedal 18, or When the lockup clutch 22d is switched to the disengaged position by an on-to-off switching operation or a range switching operation by the range selector 44, the direct connection until the calculated parameter becomes less than the first threshold value thereafter. Since switching to the position or slip position is prohibited (S26, S28, S30), in addition to the above-described effects, normal control and first protection control can be smoothly switched.

  Further, the control means determines whether or not the driver's required driving force is changed to a required driving force change state after the calculated parameter is reduced to less than the first threshold (S100, S102). , S104), when it is determined that the required driving force is changed, the control is returned from the first protection control or the second protection control to the control based on the map characteristics (S106). In addition, it is possible to more smoothly switch from the first and second protection control to the normal control by performing the operation when it is difficult for the driver to experience.

  In the above description, the first estimated value (command value-based LC transmission torque) of the lockup clutch 22d is calculated based on the command value LCCCMD given to the electromagnetic control valve in the flow chart of FIG. Based on the output torque of the power source (engine torque TEN) and the rotational speed of the drive source (engine speed NE), a second estimated value (LC transmission torque based on the estimated torque base) of the transmission torque of the lockup clutch 22d is calculated. Then, either the first estimated value or the second estimated value of the calculated transmission torque, more specifically, the minimum value is selected, and the load state of the friction material 22d3 of the lockup clutch 22d is selected based on the selected minimum value. The parameter indicating friction material (heat generation amount of friction material) is calculated, but the calculation of the parameter indicating the load state of the friction material is limited to that. Rather, it may be calculated from any value.

  Further, although a continuously variable transmission mechanism has been disclosed as a transmission, it is not limited thereto. Further, although the engine is disclosed as the drive source, the present invention is not limited to this, and the drive source may be an electric motor or a hybrid of the electric motor and the engine.

  DESCRIPTION OF SYMBOLS 10 engine (internal combustion engine, drive source), 12 drive wheel, 14 vehicle, 16 throttle valve, 18 accelerator pedal, 20 DBW mechanism, 22 torque converter, 22b pump impeller, 22c turbine runner, 22d lockup clutch, 22d3 friction material, 24 automatic transmission, 26 CVT (continuously variable transmission mechanism), 26a drive pulley, 26b driven pulley, 26c belt, 28 forward / reverse switching mechanism, 28a forward clutch, 28b reverse brake clutch, 34 disc brake, 36 brake pedal, 46 shift Machine hydraulic pressure supply mechanism, 46a hydraulic pump, 46v fourth linear solenoid valve, 46w on / off solenoid valve, 66 engine controller, 76 V sensor, 82 pressure sensor (82a, 82b, 82c), 0 shift controller, MS main shaft, CS counter shaft

Claims (3)

  A pump impeller coupled to a drive source mounted on a vehicle; a turbine runner coupled to a transmission; a torque converter having a lockup clutch that can directly connect the pump impeller and the turbine runner; and the vehicle speed and the drive of the vehicle A slip position between the direct connection position where the pump impeller and the turbine runner are directly connected, the release position where they are released, and the direct connection position and the release position based on a map characteristic which is set so as to be searchable from the driver's required driving force with respect to the source A control unit for controlling the lock-up clutch so that the position of the lock-up clutch is any one of the positions, a parameter calculation unit that calculates a parameter indicating a load state of the friction material of the lock-up clutch; The parameter calculated by the parameter calculating means Comparing means for comparing the first threshold value and the second threshold value, which are set in consideration of the degree of weight reduction of the durability of the clutch, and the control means, wherein the calculated parameter is not less than the first threshold value. When it is determined that the value is less than the second threshold value, the control of the lockup clutch based on the map characteristic is continued, and when the lockup clutch is switched to the release position, the control is switched to the direct connection position or the slip position. When the calculated parameter is determined to be greater than or equal to the second threshold value, the lockup clutch is immediately switched to the disengaged position, and thereafter, the calculated parameter is The second protection control is executed to prohibit switching to the direct connection position or the release position until the value becomes less than the first threshold value. Lockup clutch control apparatus according to claim and.   When the lock-up clutch is switched to the disengaged position by the control based on the map characteristics or by a predetermined operation by the driver in the first protection control, the control means thereafter calculates the parameter 2. The control device for a lockup clutch according to claim 1, wherein switching to the direct connection position or the slip position is prohibited until the value becomes less than the first threshold value.   The control means determines whether or not the driver's requested driving force is in a changed requested driving force change state after the calculated parameter has decreased to less than the first threshold, and the requested driving force change 3. The lockup clutch control device according to claim 1, wherein when the state is determined to be in a state, the control is returned from the first protection control or the second protection control to the control based on the map characteristic.

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