JP2009079715A - Shift control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deterioration of traveling performance by improving a shift tolerance. <P>SOLUTION: This shift control device for an automatic transmission comprises a present thermal load calculating means calculating present thermal load states of friction elements, calorific value predicting means (S24, S31, S35 and S41) predicting calorific values in the friction elements before the start of a shift when the shift is performed, thermal load predicting means (S25, S32, S36 and S42) predicting the thermal load states of the friction elements upon shift completion based on the thermal load states of the friction elements and the calorific value predicted by the calorific value predicting means, and a shift control means changing a shift mode to perform or prohibit the shift when the thermal load states upon the shift completion predicted by the thermal load predicting means are brought into prescribed states so that the calorific values of the friction elements are reduced in comparison with that in the case that the prescribed states are not generated. The prescribed state is set in a different state depending on whether the shift is an upshift or a downshift. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a shift control device for an automatic transmission.

  In general, an automatic transmission for an automobile is such that an engine rotation is input via a torque converter, and is shifted to a drive shaft or a propeller shaft (axle side) by a speed change mechanism having a plurality of planetary gears. Are known.

  In this type of automatic transmission, the transmission mechanism transmits the rotation of the input shaft (input shaft) to a specific gear or carrier constituting the planetary gear according to the shift position, or appropriately outputs the rotation of the specific gear or carrier. Shifting is performed by transmitting to the shaft. In addition, a plurality of friction elements such as clutches and brakes are provided to restrain the rotation of a specific gear or carrier as appropriate at the time of shifting, and the transmission path is switched by a combination of engagement and release of these friction elements to achieve a predetermined shifting speed. Is configured to be performed. In general, these friction elements are applied with a hydraulic clutch or brake whose engagement state is controlled by a hydraulic supply / discharge state.

  By the way, in a conventional automatic transmission, when a predetermined shift is performed, if the vehicle is traveling in the vicinity of the boundary region of the vehicle traveling condition, the selected gear stage may fluctuate and the shift may be repeated. is there. For example, when the 3-4 shift from the 3rd speed to the 4th speed is performed, the 3-4 shift from the 3rd speed to the 4th speed and the 4-3 shift from the 4th speed to the 3rd speed are repeated. A continuous shift such as -3--4 -... is performed.

  If such speed change is continuously performed, the same friction element is repeatedly engaged and released over a long period of time, so the thermal load applied to the friction element increases (temperature rises), and the friction element seizes. Risk of burning. In this specification, “thermal load” is used to mean “temperature” or “heat generation”.

  In response to such a problem, for example, Patent Document 1 below discloses a technique using a timer. Specifically, the timer is counted down during continuous gear shifting, and when the timer value reaches a predetermined value, it is assumed that the thermal load state (temperature) of the friction element has reached the burnout temperature. Shifting is prohibited. In addition, when the continuous shift is completed before reaching the set value, the timer is counted up with a certain gradient, assuming that heat is being released.

As a result, when the continuous shift is resumed immediately after the end of the continuous shift, the timer value starts counting down from a value smaller than the initial value, and the control in consideration of the amount of heat accumulated in the friction element is performed. Executed.
Japanese Patent No. 3402220

  However, in the above conventional technique, time is only used as a parameter regardless of the shift type and input torque, and since it does not consider what shift the next shift is, a timer for determining shift prohibition The predetermined value is set so that the friction element is not damaged regardless of the type of the subsequent shift. That is, the predetermined value of the timer value is set to a value having a sufficient margin for the actual damage temperature so that the friction element is not damaged even when a shift at which the amount of heat generation is maximum occurs. As a result, even if the determined shift is a shift that does not generate a large amount of heat and the friction element does not reach the damage temperature even when this shift is performed, the shift is uniformly prohibited. Drivability deteriorates.

  In particular, when the shift is downshift, an upshift may occur immediately after the downshift to prevent engine overrevs. Therefore, it is necessary to expect a larger amount of heat generated by the downshift than the upshift. There is. Therefore, if the predetermined value for determining whether to prohibit the shift is set to be the same regardless of the shift type, the shift on the upshift side will be excessively limited.

  An object of the present invention is to prevent deterioration in drivability by improving the shift allowance.

  The present invention relates to a current thermal load state of a friction element in a shift control device for an automatic transmission that performs a shift from a current shift stage to a target shift stage by selectively engaging or releasing a plurality of friction elements. Current heat load calculating means for calculating the heat generation amount, the heat generation amount prediction means for predicting the heat generation amount in the friction element when shifting is performed before the start of the shift, the current thermal load state of the friction element, and the heat generation amount prediction means The thermal load predicting means for predicting the thermal load state at the end of the shift of the friction element on the basis of the calorific value predicted by the above, and the thermal load state at the end of the shift predicted by the thermal load predicting means A shift control means for changing the speed change mode so that the amount of heat generated by the friction element is less when the predetermined state is not required, or prohibiting the shift; Shift or da Nshifuto or in has been set to a different state.

  According to the present invention, the predetermined state for determining permission or prohibition of shifting is set to a different state depending on whether the type of shifting is upshift or downshift, so that maximum shifting is permitted for each shifting type. And deterioration of drivability can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a functional block diagram showing the configuration of a shift control device for an automatic transmission according to this embodiment. FIG. 2 is a skeleton diagram showing the configuration of the automatic transmission. As shown in FIG. 1, the speed change control apparatus includes a controller 1, an input shaft rotational speed sensor (turbine shaft rotational speed sensor) 12 that detects rotational speeds NT of the turbine 25 and the turbine shaft 10, and a rotational speed No of the output shaft 28. Output shaft rotation speed sensor (vehicle speed sensor) 13, oil temperature sensor 14 for detecting the temperature of ATF (automatic transmission oil), throttle sensor 30 for detecting the throttle opening of the engine (not shown), engine intake air amount The air flow sensor 31 for detecting the engine speed and the engine speed sensor 32 for detecting the engine speed NE and the hydraulic circuit 11 of the automatic transmission 7 are configured. The controller 1 controls the sensors 12, 13, While determining a desired target gear position based on detection signals from 14, 30, 31, 32, etc., It performs shift control to achieve the target gear position via the hydraulic circuit 11.

  The gear stage of the automatic transmission 7 is determined by the engagement relationship of friction elements such as a planetary gear unit, a plurality of hydraulic clutches and a hydraulic brake provided in the automatic transmission 7. For example, FIG. 1 shows the automatic transmission 7 in the case of a four-speed shift. The first clutch 15, the second clutch 17, the third clutch 19, the first brake 22, and the second brake 23 are used as friction elements. I have it. Details of the automatic transmission 7 are shown in FIG. In FIG. 2, the reference numerals indicating the friction elements correspond to those shown in FIG.

  Control of the friction elements 15, 17, 19, 22, 23 by the controller 1 is performed via the hydraulic circuit 11 shown in FIG. In other words, the hydraulic circuit 11 is provided with a plurality of solenoid valves (not shown), and by appropriately driving (duty control) these solenoid valves, the ATF delivered from the oil pump is changed to the friction elements 15, 17, 19, 22, 23. The controller 1 determines the target gear position based on the throttle opening detected by the throttle sensor 30 and the vehicle speed calculated based on the rotational speed No of the output shaft 28 detected by the output shaft rotational speed sensor 13, A drive signal (duty ratio signal) is output to the solenoid valves of the friction elements 15, 17, 19, 22, and 23 involved in the shift to the determined target shift speed. The ATF is regulated to a predetermined oil pressure (line pressure) by a regulator valve (not shown), and the ATF regulated to this line pressure is to operate the friction elements 15, 17, 19, 22, and 23. Supplied to the hydraulic circuit 11.

  Incidentally, a shift map 3 is provided in the controller 1. Further, the automatic transmission 7 is equipped with a switching lever (not shown) for switching the operation mode, and when the driver operates the switching lever, the parking range, the traveling range (for example, the first gear to the fourth gear). Speed range), neutral range, reverse range, etc. can be manually selected.

There are two shift modes in the travel range, an automatic shift mode and a manual shift mode (manual shift mode). When the automatic shift mode is selected, a preset range is set based on the throttle opening θ _TH and the vehicle speed V. A shift determination is performed according to the shift map 3, and the shift is automatically performed according to this determination. On the other hand, when the manual shift mode is selected, the gear stage is shifted to the gear stage selected by the driver regardless of the shift map 3, and then fixed.

For example, characteristics as shown in FIG. 4 are stored in the shift map 3. At the time of a normal shift in which the shift is automatically performed, the vehicle speed V detected by the vehicle speed sensor 13 and the throttle opening θ _TH detected by the throttle sensor 30 based on the shift map 3 shown in FIG. 3 and the first and third clutches 15, 17, 19 and the first and second brakes 22, 23, etc., are controlled by the solenoid valves respectively set. Each gear stage is automatically established by a combination of engagement or release as shown in FIG. Note that the circles in FIG. 3 indicate the coupling of each clutch or each brake.

  As shown in FIG. 3, for example, when the first clutch 15 and the second brake 23 are engaged and the second clutch 17, the third clutch 19, and the first brake 22 are released, the second speed is achieved. The shift from the second speed to the third speed is achieved by releasing the engaged second brake 23 and engaging the second clutch 17. The engagement state of these friction elements 15, 17, 19, 22, 23 is controlled by the controller 1, and the gear position is determined by the engagement relationship of these friction elements 15, 17, 19, 22, 23, Shift control is performed with appropriate timing of fastening and releasing.

  At the time of shifting, a drive signal is output from the controller 1 to each solenoid valve, and each solenoid valve is driven at a predetermined duty value (duty rate) based on this drive signal, so that optimum shift control with good shift feeling is achieved. Is executed.

Next, the main part of the present embodiment will be described in detail. The apparatus always calculates the current thermal load state (temperature) of each friction element (hereinafter simply referred to as “clutch”), and when a shift is determined. The clutch rising temperature T _INH at the time of shifting is estimated, and the prohibition or permission of shifting is executed based on these results.

  Specifically, when the driving point crosses the upshift line and the downshift line of the shift map 3 continuously and repeatedly, for example, 3-4 shift and 4-3 shift between 3rd speed and 4th speed are performed. It is conceivable that repeated shifts such as 3-4-3-4-... Are repeated. Alternatively, it is conceivable that a continuous gear shift such as 3-4-3-4-... Is performed in the same manner as described above even when the third speed and the fourth speed are frequently switched by the shift lever operation by the driver. .

  When such a continuous shift is performed, a specific clutch (in the case of 3-4 continuous shift, the first clutch 15 and the second brake 23; see FIG. 3) repeats engagement and release. If the engagement and disengagement are repeatedly executed in a short time in this way, it is considered that the heat capacity of the clutch increases (temperature rises) and the clutch or brake is seized.

  In addition, as in the prior art, in the case where the thermal load state of the clutch is simply predicted with a timer and the shift is prohibited without considering the shift type, engagement release state, and input torque, An accurate temperature cannot be obtained. For this reason, the threshold value for determining prohibition of shifting is set to a value with a sufficient margin so that the clutch does not reach the burnout temperature even when shifting is performed so that the largest amount of heat is generated. In spite of being in an allowable state, it is conceivable that the shift is prohibited and drivability is impaired.

Therefore, in this embodiment, the thermal load state (current temperature) is calculated for each clutch, and when a shift is determined, an increase in temperature for each clutch is predicted to accurately prohibit or allow the shift. It is comprised so that it may judge. That is, as shown in FIG. 5, in addition to the shift map 3, the controller 1 includes a current temperature calculation means 101 (current thermal load calculation means) for calculating the current temperature of each clutch, and the next shift. A predicted rise temperature calculating means 102 (heat generation amount prediction means) for predicting the clutch rise temperature T _INH , and a predicted temperature T _{ES of the} clutch at the next shift based on the current clutch temperature and the predicted rise temperature Based on whether the predicted temperature T _ES is equal to or higher than a predetermined value by the predicted temperature calculation unit 103 (thermal load prediction unit), the comparison unit 109 that compares the predicted temperature T _ES with a predetermined threshold value, and the comparison unit 109. , A shift prohibition switching means 104 (shift control means) for permitting or prohibiting the next shift or switching to another shift.

  First, the current temperature calculation means 101 will be described.

The current temperature calculation means 101 sequentially calculates and updates the current temperature of each clutch, and an ATF temperature T _OIL obtained by the oil temperature sensor 14 is set as an initial value when the engine is started. This is because the temperature of each clutch of the transmission 7 can be regarded as approximately the oil temperature T _OIL when the engine is started.

Here, FIG. 6 is a diagram in which the validity of applying the oil temperature T _OIL as the initial value of the clutch temperature at the time of starting the engine is verified. In the drawing, V _SP indicates the vehicle speed.

As shown in the drawing, the temperature of the clutch (corresponding to the second brake 23 in the present embodiment; see FIG. 3) that is engaged when shifting from the first speed to the second speed may be intentionally burned (burnout temperature). In this state, the vehicle speed is decreased at a constant gradient. Then, after downshifting to the first speed, when the vehicle speed V _SP = 0, the engine is stopped as ignition off (IGN-OFF) (see t1 in the figure). Here, after IGN-OFF, the engine is restarted (IGNON) (see t2), and the accelerator is fully opened to be upshifted to the second speed (see t3).

In this example, a case was simulated where a downshift from the first speed (see t0) to an upshift to the second speed (see t3) takes about 10 seconds, but the clutch temperature decreases with a predetermined gradient from t0. For this reason, it was confirmed that the oil temperature in the oil pan had been lowered to the oil temperature _{TOIL for} about 10 seconds.

Thus, even if the engine is restarted immediately after the engine is stopped, it has been experimentally confirmed that the temperature of the clutch is about the oil temperature T _OIL . Therefore, the oil temperature T _OIL is set as the initial temperature when starting the engine. There is no problem with setting.

When the initial temperature value of the clutch is set as described above, the current temperature calculation unit 101 calculates the clutch temperature Tc by a different method depending on the current state of the clutch. . That is, in the clutch, the thermal load (heat generation amount T _up ) is different at the time of engagement and at the time of release, and the thermal load is different at the time of shifting transient and at the time of steady state. Further, the thermal load generated in the clutch differs between downshift and upshift. For this reason, as shown in FIG. 5, the current temperature calculation means 101 includes a heat generation amount calculation means 105 for calculating the heat generation at the time of engagement and disengagement of the clutch, and a heat release amount calculation means 106 at the time of steady engagement and release. Further, the calorific value calculation means 105 includes a fastening transient calorific value calculation means 107 that calculates the heat generation during the fastening transition, and a release transient calorific value calculation means 108 that calculates the heat dissipation amount during the release transition. Is provided.

  In this embodiment, “engagement transient” refers to the torque phase or inertia phase of the clutch to be engaged, and “release transient” refers to the torque phase or inertia phase of the clutch to be released. Use as Further, the “engagement steady state” means that the target clutch is in the engagement completion state and is not in the torque phase or the inertia phase, regardless of whether or not the gear change command is being issued or not. Furthermore, “relative release” indicates that the target clutch is in a completely released state.

  Here, FIG. 7 is a diagram showing a characteristic of a temperature change accompanying the engagement and disengagement of the clutch at the time of actual upshift, and as shown in the figure, the temperature rises most during the period from the start of clutch engagement to the end of engagement. . At this time, the gradient of temperature change is the largest. Further, when the clutch is engaged and becomes a steady state, the temperature decreases with a certain gradient. When the clutch starts to be released, the temperature drop up to that point and the temperature rise due to frictional heat due to the relative rotation of the clutch cancel each other, resulting in a substantially constant temperature, and the temperature change of the clutch becomes minute (in FIG. Shown as constant temperature Tc).

  Further, when the release of the clutch ends (during steady release), the temperature decreases with a predetermined gradient. Note that the temperature decrease gradient after releasing the clutch (at the time of steady release) at this time is larger (the inclination is larger) than the temperature decrease gradient after engaging the clutch (at the time of steady engagement).

Therefore, the current temperature calculation means 101 calculates the clutch temperature Tc in consideration of such temperature change characteristics. Here, the calculation of the clutch temperature T _C by the current temperature calculation means 101 will be described in detail. In the current temperature calculation means 101, the current shift speed and the target shift speed are input when judging the shift based on the information from the shift map 3. Furthermore, the turbine rotational speed NT and the engine rotational speed NE are input from the turbine rotational speed sensor 12 and the engine rotational speed sensor 32.

  Then, among the plurality of clutches, a clutch that is engaged or disengaged (that is, in the case where the transmission 7 is in a non-shifting operation, or in the case of a shifting operation in which the clutch is not involved even in the shifting operation, for example, 2 The third clutch 19 and the first brake 22) during the third speed shift are not in a state in which the clutch is in a steady state and the clutch is in sliding contact with a capacity, so that frictional heat is not generated in the clutch. The temperature will not rise. For this reason, the heat dissipation amount is calculated by the heat dissipation amount calculation means 106.

Here, the heat dissipation amount calculation means 106 calculates a heat dissipation amount (temperature reduction allowance) _Tdown based on the following equations (1) and (2). In the control of the controller 1, since the heat generation amount T _up is treated as + and the heat radiation amount is −, the heat radiation amount T _down <0 in the following equations (1) and (2).
Release state: T _down = −A × t _c (t ≦ t1), T _down = −B × t _c (t1 ≦ t) (1)
However, A is a variable, B is a constant, t _c is an interval, t is an elapsed time after the end of shifting, t 1 is a predetermined time engagement state: T _down = −C × t _c (t ≦ t 1), T _down = −D × t _c (t1 ≦ t) (2)
Where C is a variable, D is a constant, t _c is an interval, t is an elapsed time after the end of a shift, and t 1 is a predetermined time.

That is, the heat dissipation amount calculation means 106 calculates the heat dissipation amount _Tdown on the assumption that the clutch temperature Tc decreases at the gradients A and C, which are variables, until the predetermined time t1 elapses after the shift is completed and the steady state is reached. Then, after a predetermined time t1 has elapsed since the end of the shift, the heat radiation amount _Tdown is calculated assuming that the clutch temperature Tc decreases with the constant gradients B and D. The variables A and C are values determined based on the temperature difference between the clutch current temperature Tc and the oil temperature T _OIL, and are set to values that increase as the temperature difference increases. Further, the gradients B and C, which are constants, are set such that B> C, and as shown in FIG. This is because the lubricating oil is more easily supplied to the facing surface of the clutch in the stationary release state than in the stationary engagement state, and as a result, a large heat dissipation can be performed.

A new clutch current temperature Tc is calculated by adding the currently calculated heat dissipation amount _Tdown to the previously calculated clutch current temperature Tc.

Here, at the time of steady engagement or disengagement of the clutch, the clutch temperature Tc decreases with a predetermined gradient from the formulas (1) and (2) in calculation. Therefore, if the target clutch is maintained in a steady state for a long time, it is actually Therefore, a temperature that is impossible (for example, a temperature lower than the oil temperature T _OIL ) is calculated.

Therefore, when the clutch engagement or disengagement steady state continues for a predetermined time, the heat dissipation amount calculation means 106 resets the calculation of the heat dissipation amount _Tdown according to the expressions (1) and (2) (or clips the lower limit value). A function is provided. That is, the heat release amount calculation means 106 is provided with a reset determination timer (not shown), and the timer starts counting when it is determined that the fastening steady state or the releasing steady state is started.

If the timer counts that the clutch is in the engagement steady state or the release steady state and this state has continued for a predetermined time, the calculation of the clutch temperature Tc based on the equations (1) and (2) is cancelled. In this case, the clutch temperature Tc should be sufficiently lowered to be equal to the oil temperature T _OIL , so that the clutch temperature Tc is made to coincide with the current oil temperature T _OIL thereafter.

Even if the count of the timer does not exceed the predetermined time, when the current clutch temperature Tc becomes equal to or lower than the oil temperature T _OIL , the clutch temperature Tc = the oil temperature T _OIL is set thereafter.

  On the other hand, when the state of the clutch changes to the release transition or the engagement transition within a predetermined time from the start of the count of the timer, the timer is reset and the count returns to the initial value. As a result, when the clutch changes from the transient state to the steady state again, the count starts from the initial value.

  Here, with reference to FIG. 8, the operation of the reset determination timer when the continuous shift is performed between the Nth stage and the N + 1th stage will be described. FIG. 8A is a diagram illustrating a change in the clutch temperature Tc. (B) is a figure shown about the count of a reset determination timer.

  As shown in FIG. 8A, when a continuous shift occurs, the clutch temperature Tc increases every time the clutch is engaged. Note that the clutch temperature Tc decreases at the time of clutch engagement steady state and at the time of steady release, but when continuous shift is performed in a short time, the temperature decrease is small compared to the temperature increase at the clutch engagement transition time.

On the other hand, as shown in FIG. 8B, the count of the timer is reset every time a shift is started (at the time of transition). In this example, the count of the timer is continued when the clutch shifts to the engaged steady state. When the timer count reaches a predetermined value, as shown in FIG. 8A, after that, it is determined that the clutch temperature Tc has decreased to the oil temperature T _OIL and the clutch temperature Tc is set to the oil pan temperature T _OIL . It is like that. Further, the timer count is held at a set value or a maximum value set to a value larger than the set value.

  Next, temperature calculation (heat generation) at the time of clutch engagement or disengagement transition will be described.

  In this case, the heat generation amount calculation means 105 calculates the current temperature of the clutch as needed. First, when it is determined that the clutch is in a transient state based on information from the turbine rotational speed sensor 12 or the like, the heat generation amount calculation means 105 determines whether the clutch is in a release transition state or an engagement transition time.

When it is determined that the clutch is in the engagement transition state (for example, the second clutch 17 during the 2 → 3 shift), the engagement heat generation amount calculation means 107 provided in the heat generation amount calculation means 105 causes the heat generation amount of the clutch. T _up is calculated.

  Based on the information from the shift map 3, the engagement transient heat generation amount calculation means 107 determines whether the currently proceeding shift is an upshift or a downshift. Here, even when the clutch is in the engagement transition state, the amount of heat generation is greatly different between the upshift and the downshift, and the engagement transition during the upshift has a larger amount of heat generation than that during the downshift. On the other hand, the amount of heat generated during downshifting is not so large as compared with upshifting even when the clutch is in transitional engagement.

This is because the downshift, when the disengagement side clutch is disengaged increases engine speed by itself, since the engagement side clutch is engaged at a timing synchronized with, the heat generation amount T _up of the engagement side clutch than the upshift Because it is small.

Therefore, in this embodiment, when it is determined that the engagement is in a transitional transition state, and when it is determined that the shift is an upshift, the heat generation amount T _{UP of the} clutch is calculated based on the following equation (3), and the downshift is performed. If the shift is determined, the heat generation amount T _UP is set based on the following equation (4).
T _UP = (ΔN × T _in × Δt / 1000) × A × α (3)
T _UP = 0 (4)
However, in the formula (3), .DELTA.N the relative rotational speed of the clutch, T _in the transmission torque of the clutch, Delta] t is very small shift time, A is a constant for converting the amount of energy in temperature, alpha matching constant (correction coefficient ). The relative rotational speed ΔN of the clutch depends on the turbine rotational speed NT obtained by the turbine rotational speed sensor 12, the output shaft rotational speed No obtained by the output shaft rotational speed sensor 13, and the gear ratio of each gear of the transmission. Calculated based on The clutch transmission torque is calculated from the duty value of the solenoid valve for each clutch, that is, the hydraulic pressure value.

Further, since the heat generation amount _Tup is small at the time of downshifting even at the time of fastening transition, in this embodiment, the heat generation amount _TUP = 0 at the time of downshifting is set as shown in Expression (4). . This is because, as described above, when the clutch is in the engagement transition, the temperature drop (heat radiation) due to the lubricating oil and the temperature rise due to relatively small heat generation are offset, and the temperature becomes substantially constant.

In this way, during upshifting, the heat generation amount T _UP is calculated every cycle by integration during shifting, and the clutch temperature Tc calculated in the previous control cycle is added to the calculated heat generation amount T _UP . Thus, the current clutch temperature Tc is calculated. As described above, the initial value of the clutch temperature Tc is set to the ATF temperature T _OIL obtained by the oil temperature sensor 14.

On the other hand, when it is determined that the clutch is in the release transition state (for example, the second brake 23 during the 2 → 3 shift), the release transient heat generation amount calculation unit 108 provided in the heat generation amount calculation unit 105 performs the clutch release. A calorific value T _up is calculated.

  Based on the information from the shift map 3, the release transient heat generation amount calculation means 108 determines whether the currently proceeding shift is an upshift or a downshift. Here, even when the clutch is in the disengagement transition state, the amount of heat generation differs greatly between the upshift and the downshift, and contrary to the engagement transition, the disengagement transition during the downshift has a larger amount of heat generation than during the upshift. On the other hand, at the time of upshifting, even if the clutch is in a transitional release transition, the amount of heat generation is not large compared to the downshifting.

Therefore, when it is determined that the shift is an upshift, the heat generation amount _Tup is calculated based on the above-described equation (4), and when it is determined that the shift is a downshift, based on the equation (3). A calorific value T _up is calculated.

When the controller 1 determines the speed change while calculating the current clutch temperature Tc as described above, when the next speed change is executed from the current temperature state, the clutch rising temperature T related to the speed change is determined. Predict _INH .

The prediction of the rising temperature T _INH is executed by the predicted rising temperature calculation means 102 provided in the controller 1. Here, as shown in FIG. 5, the predicted increase temperature calculation means 102 includes an UP shift predicted increase temperature calculation means 111 for predicting the clutch increase temperature T _INH at the time of upshift, and a clutch increase temperature at the time of normal downshift. the normal DOWN shift predicted temperature increase calculation unit 112 that predicts the T _INH, a PYDOWN shift predicted temperature increase calculation unit 113 that predicts the clutch temperature increase T _INH during the PYDOWN shift to be described later, during a second synchronization shift And a second synchronized shift predicted temperature increase calculating means 114 for predicting the clutch temperature increase _TINH .

When the controller 1 makes an upshift determination or a downshift determination, the rising temperature T _INH is predicted prior to the actual upshift command or downshift command. The calculation method in each predicted rise temperature calculation means will be described later.

When the predicted rise temperature T _INH at the next shift to be performed is calculated by the predicted rise temperature calculating means 102 in this way, the predicted rise temperature T _INH and the current temperature calculating means 101 are calculated as shown in FIG. The current clutch temperature Tc is input to the predicted temperature calculation means 103.

The predicted temperature calculation means 103 adds the predicted increase temperature T _INH to the current clutch temperature Tc, and calculates the predicted temperature T _ES when the shift is completed at the next shift.

Further, as shown in FIG. 5, the controller 1 is provided with a threshold storage unit 110, and the threshold storage unit 110 stores an UP burnout temperature and a DOWN burnout temperature. The UP burnout temperature is a temperature at which the clutch burns out when the clutch temperature Tc exceeds, and is used to determine whether or not the clutch temperature Tc after the shift exceeds during an upshift (hereinafter also referred to as UP shift). The The DOWN burnout temperature is a temperature lower than the UP burnout temperature used to determine whether or not the clutch temperature Tc after the shift exceeds during downshift (hereinafter also referred to as DOWN shift). This is a temperature obtained by subtracting the temperature increase due to the maximum heat generation amount T _up due to the shift. Note that the PYUP shift in the normal UP calorific T _up from shift is small shift mode is to perform the shift of the shift determination, which will be described later.

The comparison means 109 compares the predicted temperature T _ES with the UP burnout temperature or the DOWN burnout temperature, and when it is determined that the predicted temperature T _ES is equal to or higher than the UP burnout temperature or the DOWN burnout temperature, the shift prohibition switching means 104 determines the shift. The upshift or downshift performed is prohibited or switched to another shift. Here, the other shift is a PYUP shift for an upshift performed in a normal shift mode and a PYDOWN shift for a downshift performed in a normal shift mode. On the other hand, if it is determined that the predicted temperature T _ES is lower than the UP burnout temperature or the DOWN burnout temperature, the shift determined to be shifted is permitted, and an upshift or a downshift is executed in a normal shift mode.

Further, as shown in FIG. 5, the controller 1 is provided with a continuous change mind shift permission number calculation means 120. The change mind means that a new shift determination to the n-th stage is made during a shift operation from the n-th stage to the n + 1-th stage or the n-1-th stage. When it is determined that the shift determination is a change mind, the number of times of continuous change mind shift permission is calculated based on the current clutch temperature Tc without predicting the clutch rising temperature T _INH .

  Thereafter, the comparison means 109 compares the current number of continuous change-mind shifts with the number of permitted continuous change-mind shifts, and determines that the current number of continuous change-mind shifts is equal to or greater than the number of permitted continuous change-mind shifts. The execution of upshift or downshift is prohibited. On the other hand, if it is determined that the current number of continuous change-mind shifts is less than the number of permitted continuous change-mind shifts, the execution of the upshift or downshift determined for the shift is permitted.

  When there is a possibility that the clutch may be burned by the above control, the upshift or downshift of the next shift is prohibited, or the execution is switched from the normal shift mode to another shift mode, and the clutch is determined not to burn. Since upshifting or downshifting is allowed when possible, it is possible to prohibit and permit appropriate shifting according to the thermal load state of the clutch.

Here, the above-described PYUP shift and PYDOWN shift will be described. The PYUP shift and the PYDOWN shift are shift modes in which the shift time is shortened and the heat generation amount T _up is reduced correspondingly when compared with the normal upshift and downshift modes with the same input torque. Specifically, the shift time is shortened by increasing the hydraulic oil pressure increase and decrease gradients.

  In the following specification, the term “upshift” is used to mean that the gear position is switched to a high gear, and the term “UP gearshift” is performed in a normal gear mode. This is an upshift, and is used to clarify a difference from an upshift (for example, PYUP shift) that is mainly performed in another shift mode. Similarly, the term “downshift” is used to mean that the gear position is switched to a low gear position, and the term “DOWN gearshift” is a downshift performed in a normal gearshift mode. It is used to clarify the difference from downshifts (for example, PYDOWN shift) performed mainly in other shift modes.

  First, the PYUP shift will be described with reference to FIG. FIG. 9 is a time chart showing changes in gear ratio, release side clutch hydraulic pressure command value, engagement side clutch hydraulic pressure command value and engine torque in PYUP shift, and a broken line indicates a normal shift mode (normal UP shift). A solid line indicates a speed change mode (PYUP speed change) with a small amount of heat generation.

  As shown by the solid line in FIG. 9, the engagement-side clutch has a hydraulic pressure increase gradient during the torque phase (t1 to t2) and a hydraulic pressure during the inertia phase (t2 to t3) with respect to the normal shift mode (normal UP shift). It is controlled so that the ascending gradient of becomes large. Further, the release side clutch is controlled so that the gradient of decrease of the oil pressure during the torque phase (t1 to t2) becomes large. This is because even if the engagement-side clutch starts to have capacity, if the release-side clutch still has capacity, there is a possibility of causing an interlock.

As a result, it takes only t4-t1 time in the normal shift mode (normal UP shift) until the gear ratio changes from the n stage to the n + 1 stage, whereas the PYUP shift requires only t3-t1 time. , T4-t3 time can be shortened. Therefore, reduced by the time amount of the heat generation amount T _up of the engagement side clutch is reduced.

  In the upshift, engine torque reduction control is performed during the inertia phase, but in the PYUP shift, the torque reduction amount is set to a larger value, so even if the engagement side clutch is engaged in a shorter time by the PYUP shift. The deterioration of the shift shock can be suppressed.

  Similarly, PYDOWN shift will be described with reference to FIG. FIG. 10 is a time chart showing changes in the gear ratio, disengagement side clutch hydraulic pressure command value, and engagement side clutch hydraulic pressure command value in the PYDOWN shift. The broken line indicates the normal shift mode (normal DOWN shift), and the solid line indicates heat generation. A shift mode (PYDOWN shift) with a small amount is shown.

  As shown by the solid line in FIG. 10, the release side clutch has a hydraulic pressure decrease gradient from the start of the shift to the start of the inertia phase (t1 to t2) and an increase in the hydraulic pressure during the inertia phase (t2 to t3) with respect to the normal shift. The gradient is controlled to be large. Further, the engagement side clutch is controlled so that the rising gradient of the hydraulic pressure during the inertia phase (t2 to t3) becomes large.

As a result, it takes only t6-t1 hours for the normal gear shift until the gear ratio changes from the n-th stage to the n-1 stage, whereas t4-t1 time is required for the PYDOWN shift. Can only be shortened. Therefore, reduced by the time amount of the heat generation amount T _up of the disengagement side clutch is reduced.

  The control performed by the controller 1 described with reference to FIG. 5 as described above will be described in detail below with reference to the flowcharts of FIGS. In addition, the flowchart shown in FIGS. 11-18 is performed for every clutch.

  First, the control contents of the current temperature calculation means 101 will be described with reference to FIG.

In step S1, information such as the current engine speed NE, turbine speed NT, oil temperature T _OIL , vehicle speed No, etc. is captured.

  In step S2, it is determined that the state of the clutch is the engagement steady state, the release transient state, the release steady state, or the engagement transient state.

If the clutch state is the steady engagement state, the process proceeds to step S3, the reset determination timer is counted up, and the process proceeds to step S4 to calculate the engagement heat release amount _Tdown . The calculation of the fastening heat radiation amount _Tdown will be described later.

If the clutch state is the disengagement transient state, the process proceeds to step S5, and it is determined whether the shift type is upshift or downshift. If it is a downshift, the process proceeds to step S6, the reset determination timer is cleared, the process proceeds to step S7, and the release-time heat generation amount _Tup is calculated. The release-time heat generation amount T _up is calculated based on the above equation (3). If the shift type is upshift, the process proceeds to step S8, the reset determination timer is cleared, the process proceeds to step S9, and the heat generation amount _Tup is set to 0 based on the equation (4).

If the state of the clutch is the steady release state, the process proceeds to step S10, the reset determination timer is counted up, and the process proceeds to step S11 to calculate the released heat dissipation amount _Tdown . The calculation of the release heat radiation amount _Tdown will be described later.

If the clutch is in the engaged transition state, the process proceeds to step S12, and it is determined whether the shift type is upshift or downshift. If it is a downshift, the process proceeds to step S8, the reset determination timer is cleared, the process proceeds to step S9, and the heat generation amount _Tup is set to 0 based on the equation (4). If the shift type is upshift, the process proceeds to step S13, the reset determination timer is cleared, and the process proceeds to step S14 to calculate the engagement heating value _Tup . The fastening heat generation amount T _up is calculated based on the above equation (3).

In step S15, it is determined whether or not the reset determination timer is equal to or longer than the clutch reset set time. If the reset determination timer is equal to or longer than the clutch reset set time, the process proceeds to step S16, where the current temperature Tc of the clutch is set to the oil temperature T _OIL and the process is terminated.

If the reset determination timer is smaller than the clutch reset set time, the process proceeds to step S17, and the heat generation amount _Tup or the heat dissipation amount _Tdown is added to the current clutch temperature Tc. The heat radiation amount T _down is a negative value. Here, the clutch reset setting time is such that it can be determined that the clutch temperature Tc is sufficiently lowered to be equal to the oil temperature T _OIL because the clutch engagement or disengagement steady state has continued for a predetermined time. Is the time.

In step S18, it is determined whether or not the current clutch temperature Tc is equal to or lower than the oil temperature T _OIL . Continue the current temperature Tc of the clutch to step S16 if less oil temperature T _OIL, the current clutch temperature Tc and the oil temperature T _OIL. If the current clutch temperature Tc is higher than the oil temperature T _OIL , the process is terminated. In other words, since it is unlikely that the clutch temperature Tc is lower than the oil temperature T _OIL , when the calculated clutch temperature Tc is lower than the oil temperature T _{OIL, the} clutch temperature Tc is changed to the oil temperature T _OIL. It is what.

Here it will be described with reference to the flowchart of FIG. 12 for the calculation of the engagement heat radiation amount T _down in the step S4 of FIG. 11. Incidentally, disengagement heat radiation amount T _down in the step S11 is also computed in the same manner as operation of the engagement heat radiation amount T _down to be described below.

  In step S101, it is determined whether or not it is immediately after the end of shifting. If it is immediately after the end of the shift, the process proceeds to step S102, and if not immediately after the end of the shift, the process proceeds to step S103.

In step S102, a temperature decrease gradient is set based on the temperature difference between the clutch current temperature Tc and the oil temperature T _OIL . The temperature decrease gradient is A and C in the above formulas (1) and (2), and is set so as to increase as the temperature difference between the clutch current temperature Tc and the oil temperature T _OIL increases.

  In step S103, a timer is counted.

  In step S104, it is determined whether the timer is equal to or greater than a predetermined value. If the timer is equal to or greater than the predetermined value, the process proceeds to step S105, and the temperature decrease gradient is set to a predetermined gradient (a constant value).

In step S106, the current engagement heat release amount _Tdown is calculated from the time from the start of shifting (the value of the timer) and the temperature decrease gradient, and the process ends. Here, the predetermined value is t1 in the above formulas (1) and (2), which is the time required until the temperature decrease gradient becomes substantially constant regardless of the temperature at the start of heat dissipation, and is set to 5 sec, for example. .

  Next, referring to FIGS. 13 and 14, the control of the predicted rise temperature calculation means 102, the predicted temperature calculation means 103, the threshold value calculation means 110, the continuous change mind shift permission number calculation means 115, the comparison means 109, and the shift prohibition switching means 104 is controlled. The contents will be described.

  In step S21, it is determined whether or not there has been a shift determination. If there is a shift determination, the process proceeds to step S22, and if there is no shift determination, the process ends.

  In step S22, it is determined whether or not the shift type for which the shift is determined is change mind. If it is a change mind, the process proceeds to step S50. If it is not a change mind, the process proceeds to step S23. The change mind means that a shift to the nth stage is newly determined during the shift operation from the nth stage to the (n + 1) th stage or the (n-1) th stage.

  In step S23, it is determined whether the shift type is upshift or downshift. If it is an upshift, the process proceeds to step S24, and if it is a downshift, the process proceeds to step S29.

In step S24 (heat generation amount predicting means), a predicted temperature increase for UP shift is calculated. The predicted rising temperature for UP shift is the predicted rising temperature T _INH of the clutch that is engaged during an upshift, and a detailed calculation method will be described later.

In step S25 (thermal load predicting means), an UP shift predicted temperature T _ES is obtained by adding the UP shift predicted increase temperature to the current clutch temperature Tc.

In Step S26, the UP shift predicted temperature T _ES is equal to or higher than the UP burnout temperature (first predetermined state), in other words, the UP shift predicted temperature T _ES is in a temperature range equal to or higher than the UP burnout temperature. Determine whether it will be. If the UP shift predicted temperature T _ES is lower than the UP burnout temperature, the process proceeds to step S27 to perform the normal shift mode UP shift, and if the UP shift predicted temperature T _ES is equal to or higher than the UP burnout temperature, step S27 is performed. Proceeding to S28, a PYUP shift, which is a shift mode with a small amount of heat generation, is performed. Here, the normal UP shift, which is a normal shift mode, is a shift mode that is executed by setting the hydraulic pressure so that the driver does not experience a shift shock. This is a shift that shortens the time required to engage the clutch by increasing the rate of increase in the hydraulic pressure supplied to the clutch. In the PYUP shift, the torque reduction amount of the engine is set larger than the normal UP shift. As a result, the deterioration of the shift shock can be suppressed, and the heat generation amount T _up can also be reduced by reducing the input torque.

  On the other hand, if it is determined in step S23 that the shift type is downshift, the process proceeds to step S29 to calculate the DOWN burnout temperature. A detailed calculation method of the DOWN burnout temperature will be described later.

  In step S30, it is determined whether or not a downshift due to depression of the accelerator. If it is a downshift due to accelerator depression, the process proceeds to step S40, and if it is not a downshift due to accelerator depression, the process proceeds to step S31.

In step S31 (heat generation amount predicting means), a predicted temperature increase for normal DOWN shift is calculated. The predicted rising temperature for normal DOWN shift is the predicted rising temperature T _INH of the clutch that is released during a normal downshift, and a detailed calculation method will be described later.

In step S32 (thermal load predicting means), a normal DOWN shift predicted temperature T _ES is obtained by adding the normal DOWN shift predicted temperature increase to the current clutch temperature Tc.

In step S33, the normal DOWN shift predicted temperature T _ES is equal to or higher than the DOWN burnout temperature (second predetermined state), in other words, the normal DOWN shift predicted temperature T _ES is in a temperature range equal to or higher than the DOWN burnout temperature. It is determined whether a state is reached. If the normal DOWN shift predicted temperature T _ES is lower than the DOWN burnout temperature, the routine proceeds to step S34, where the normal DOWN shift is performed, and if the normal DOWN shift predicted temperature T _ES is equal to or higher than the DOWN burnout temperature, the routine proceeds to step S35. .

In step S35 (heat generation amount predicting means), a PYDOWN shift predicted temperature increase is calculated. The predicted increase temperature for PYDOWN shift is the predicted increase temperature T _INH of the clutch that is released during the PYDOWN shift, and a detailed calculation method will be described later. The PYDOWN shift is a shift in which the time required for releasing the clutch is shortened by increasing the rate of decrease in the hydraulic pressure supplied to the clutch compared to the normal DOWN shift which is a normal shift mode.

In step S36 (thermal load prediction means), the PYDOWN shift predicted temperature increase T _INH is added to the current clutch temperature Tc to obtain the PYDOWN shift predicted temperature T _ES .

At step S37, whether PYDOWN shift predicted temperature T _ES is DOWN burnout temperature (second predetermined state) or more, or in other words PYDOWN shift predicted temperature T _ES is entering a temperature region equal to or greater than the DOWN burnout temperature judge. PYDOWN shift predicted temperature T _ES is performed PYDOWN shift proceeds to step S38 if lower than DOWN burnout temperature, down predicted temperature T _ES for at PYDOWN shift is obtained by shift determination proceeds to step S39 if the DOWN burnout temperature or higher Prohibit execution of shift.

  On the other hand, if it is determined in step S30 that the vehicle is downshifted due to depression of the accelerator, the process proceeds to step S40, where the accelerator opening before determining that there is a shift determination in step S21 is equal to or less than a predetermined opening, and the accelerator opening. It is determined whether or not the change speed is equal to or higher than a predetermined speed. If the above condition is satisfied, the process proceeds to step S46, and if none of the above conditions is satisfied, the process proceeds to step S41. The predetermined opening is substantially zero, and the predetermined speed is set to a value that can be determined as a sudden depression of the accelerator pedal. That is, the above condition is satisfied when the accelerator opening is suddenly depressed from a substantially fully closed state. In such a case, the first synchronous control is performed, so the process proceeds to step S46, and the above condition is not satisfied. In this case, since the second synchronization control is performed, the process proceeds to step S41.

  Note that the first synchronization control and the second synchronization control are controls for engaging the clutch after synchronizing the engine speed and the rotation speed of the clutch that is engaged during downshifting. In the control, the clutch on the releasing side is released suddenly without being dragged, that is, the hydraulic pressure supplied to the clutch is lowered stepwise, whereas the second synchronous control aims to eliminate the feeling of output torque loss. The difference is that the clutch is released while being dragged, that is, the hydraulic pressure supplied to the clutch is gradually reduced.

In step S41 (heat generation amount predicting means), the second synchronous shift predicted temperature increase T _INH is calculated. The predicted increase temperature for second synchronous shift is the predicted increase temperature T _INH of the clutch that is released during the shift by the second synchronous control, and a detailed calculation method will be described later.

In step S42 (thermal load prediction means), the second synchronous shift predicted temperature T _ES is obtained by adding the second synchronous shift predicted increase temperature T _INH to the current clutch temperature Tc.

In step S43, it is determined whether or not the second synchronized shift predicted temperature T _ES is equal to or higher than the DOWN burnout temperature (second predetermined state). If the second synchronized shift predicted temperature T _ES is lower than the DOWN burnout temperature, the routine proceeds to step S44 to perform a shift by the second synchronization control, and if the second synchronized shift predicted temperature T _ES is equal to or higher than the DOWN burnout temperature. Proceeding to step S45, the downshift determined for shifting is prohibited.

  On the other hand, if it is determined in step S40 that the accelerator opening before it is determined that there is a shift command is equal to or less than the predetermined opening and the change rate of the accelerator opening is equal to or higher than the predetermined speed, the process proceeds to step S46. To read the current clutch temperature Tc.

  In step S47, it is determined whether or not the current clutch temperature Tc is equal to or higher than the DOWN burnout temperature. If the current clutch temperature Tc is lower than the DOWN burnout temperature, the process proceeds to step S48 to perform a shift by the first synchronous control. If the current clutch temperature Tc is equal to or higher than the DOWN burnout temperature, the process proceeds to step S49 and a downshift is prohibited. To do.

  On the other hand, if it is determined in step S22 that there is a change mind, the process proceeds to step S50 in FIG. 14 to determine whether the shift type is upshift or downshift. If it is determined to be an upshift, the process proceeds to step S51, and if it is determined to be a downshift, the process proceeds to step S57. Here, in step S50, as in step S23, being an upshift indicates only an upshift in the engagement transient state, and being a downshift indicates only a downshift in the release transient state.

  In step S51, the current clutch temperature Tc is read.

  In step S52, the number of continuous change mind shifts permitted by the clutch temperature Tc during the UP shift is read. The number of continuous change mind shift permission times is determined based on the clutch temperature Tc with reference to the map of FIG.

The map of FIG. 15 is divided into four regions, S region, A region, B region, and C region, according to the clutch temperature Tc, and the change mind shift permission frequency depends on which region the current clutch temperature Tc is in. It is determined. The S region is a region where the clutch temperature Tc is equal to or higher than the UP burnout temperature. The A region is a region where the clutch temperature Tc is lower than the UP burnout temperature and equal to or higher than the DOWN burnout temperature. B region, the clutch temperature Tc is lower than the DOWN burnout temperature, a temperature higher than the area obtained by subtracting the maximum heat generation amount T _up during an upshift from the UP burnout temperature. C region is a region below the temperature at which the clutch temperature Tc is obtained by subtracting the maximum heat generation amount T _up during an upshift from the UP burnout temperature.

  When the current clutch temperature Tc is in the S region, clutch burn occurs, so change mind is prohibited and the continuous change mind shift permission count is set to zero. When in the A area, even if the change mind is performed once, there is a possibility of entering the S area, so the change mind is prohibited, and the continuous change mind shift permission count is set to 0. When in the B region, the change mind of the upshift during the downshift can be limited even if the next downshift occurs, so the continuous change mind shift permission count is set to one. Although the change mind does not need to be restricted when in the C region, for example, the continuous change mind shift permission number is set to 5 here.

  Returning to FIG. 14, in step S53, it is determined whether or not the current number of continuous change-mind shifts is less than the number of continuous change-mind shifts permitted. If the current number of continuous change-mind shifts is less than the number of permitted continuous change-mind shifts, the process proceeds to step S54, the number of continuous shifts is incremented, and the process proceeds to step S55 to upshift. If the current number of continuous change-mind shifts is equal to or greater than the number of continuous change-mind shifts allowed, the process proceeds to step S56 and upshifting is prohibited.

  On the other hand, if it is determined in step S50 that the shift type is downshift, the process proceeds to step S57 and the current clutch temperature Tc is read.

  In step S58, the number of continuous change mind shifts permitted by the clutch temperature Tc at the time of downshift is read. The number of permitted continuous change mind shifts during downshifting is obtained in the same manner as the permitted number of continuous change mind shifts during upshifting determined in step S52. However, when the clutch temperature Tc is in the B region, it is different from that during upshifting. Since the downshift change mind during the upshift may be forcibly upshifted to prevent the engine from being overrevised, the change mind is prohibited in consideration of this upshift.

  In step S59, it is determined whether or not the current number of continuous change-mind shifts is less than the number of permitted continuous change-mind shifts. If the current number of continuous change-mind shifts is less than the number of permitted continuous change-mind shifts, the process proceeds to step S60 to increment the number of continuous shifts, and the process proceeds to step S61 to perform a downshift. If the current number of continuous change-mind shifts is equal to or greater than the number of continuous change-mind shifts allowed, the process proceeds to step S62 and downshifting is prohibited.

Next, the calculation of the predicted temperature increase _TINH for UP shift in step S24 of FIG. 13 will be described with reference to the flowchart of FIG. 16 and the time chart of FIG. The time chart of FIG. 20 shows (a) target shift speed NxtGP, (b) current shift speed CurGP, (c) turbine rotation speed NT, (d) output rotation speed No (vehicle speed), (e) acceleration, ( f) Relative rotational speed, (g) clutch transmission torque, (h) change in hydraulic pressure supplied to clutch. t1 to t2 are preprocessing times, t2 to t3 are torque phase target times, t3 to t4 are inertia phase target times, and the preprocessing time is the time from the shift command to the completion of the piston stroke of the clutch.

  In step S201, the acceleration at the start of preprocessing (FIG. 20 (e); t1) is calculated. The acceleration at the start of preprocessing is calculated based on the vehicle speed at the start of preprocessing and the vehicle speed before a predetermined time.

  In step S202, the preprocessing time (t2-t1) is read. The preprocessing time is a time determined based on the vehicle speed and the torque. In this embodiment, the preprocessing time backup timer of the shift control is read.

  In step S203, the vehicle speed at the start of the torque phase (FIG. 20 (d); t2) is calculated. The vehicle speed at the start of the torque phase is calculated by adding the acceleration at the start of preprocessing multiplied by the preprocessing time to the vehicle speed at the start of preprocessing.

  In step S204, the torque torque at the start of the torque phase is calculated. The turbine torque at the start of the torque phase is calculated by obtaining the turbine rotation speed NT from the vehicle speed at the start of the torque phase and the gear ratio, and referring to a rotation-torque conversion map stored in advance based on the turbine rotation speed NT.

  In step S205, the torque phase target time (t3-t2) possessed by the shift control is read based on the vehicle speed and turbine torque at the start of the torque phase.

  In step S206, the torque transmission torque at the start of the torque phase (FIG. 20 (g); t2) is calculated. The transmission torque at the start of the torque phase is a torque balanced with the return spring of the clutch, and since no hydraulic pressure is supplied at the start of the torque phase, the transmission torque at the start of the torque phase is zero.

  In step S207, the vehicle speed at the start of the inertia phase (FIG. 20 (d); t3) is calculated. The vehicle speed at the start of the inertia phase is calculated by adding the vehicle speed at the start of the torque phase to the product obtained by multiplying the acceleration at the start of preprocessing by the torque phase target time.

  In step S208, the turbine torque at the start of the inertia phase is calculated. The turbine torque at the start of the inertia phase is calculated by obtaining the turbine rotation speed NT from the vehicle speed at the start of the inertia phase and the gear ratio, and referring to the rotation-torque conversion map based on the turbine rotation speed NT.

  In step S209, the inertia phase transmission torque (FIG. 20 (g); t3) is calculated. The transmission torque at the start of the inertia phase is calculated by multiplying the turbine torque at the start of the inertia phase by the sharing ratio. Note that the sharing ratio is a ratio of the torque that each of a plurality of clutches engaged in a certain gear stage has to the input torque.

  In step S210, the torque phase average transmission torque (FIG. 20 (g)) is calculated. The torque phase average transmission torque is calculated by dividing the torque phase start transmission torque added to the inertia phase start transmission torque by two. That is, it is calculated as an average value of the torque torque at the start of the torque phase and the torque transmitted at the start of the inertia phase.

In step S211, an inertia phase start hydraulic pressure (FIG. 20 (h); t2) is calculated. The hydraulic pressure at the start of the inertia phase is calculated according to the following formula.
(Hydraulic pressure at start of inertia phase) = (transfer torque at start of inertia phase) / (A × μ × D × N) + F / A (8)
Here, A is the area, μ is the friction coefficient, D is the effective diameter, N is the number of facings, and F is the load of the return spring.

  In step S212, the inertia phase start hydraulic pressure gradient is read from the shift control map based on the inertia phase start turbine torque and the inertia phase start vehicle speed.

  In step S213, the inertia phase average oil pressure is calculated. The inertia phase average oil pressure is calculated based on the inertia phase start oil pressure, the inertia phase start oil pressure gradient, and the inertia phase target time. The inertia phase target time is a constant.

  In step S214, the inertia phase average transmission torque (FIG. 20 (g)) is calculated based on the inertia phase average oil pressure.

In step S215, the torque phase start relative rotational speed (FIG. 20 (f); t2) is calculated. The relative rotational speed at the start of the torque phase is calculated according to the following equation (9).
(Relative rotational speed at the start of the torque phase) = {A × (output rotational speed No at the start of the torque phase) + B × (turbine rotational speed NT at the start of the torque phase)} × 2π / 60 (9)
Here, A and B are relative rotation calculation constants and are obtained from the nomograph.

In step S216, an inertia phase start relative rotational speed (FIG. 20 (f); t3) is calculated. The relative rotation speed at the start of the inertia phase is calculated according to the following equation (10).
(Inertia phase start relative rotation speed) = {A × (Inertia phase start output rotation speed No) + B × (Inertia phase start turbine rotation speed NT)} × 2π / 60 (10)

  In step S217, the torque phase average relative rotational speed (FIG. 20 (f)) is calculated. The torque phase average relative rotational speed is calculated by dividing by 2 the sum of the relative rotational speed at the start of the torque phase and the relative rotational speed at the start of the inertia phase. That is, it is calculated as an average value of the relative rotational speed at the start of the torque phase and the relative rotational speed at the start of the inertia phase.

  In step S218, the inertia phase average relative rotational speed (FIG. 20 (f)) is calculated. The inertia phase average relative rotational speed is calculated by dividing the relative rotational speed at the start of the inertia phase by two. Since the relative rotational speed becomes zero at the end of the inertia phase, the relative rotational speed at the start of the inertia phase is divided by 2 to calculate an average value at the start and end of the inertia phase.

In step S219, it calculates the heat generation amount T _{Stay up-.} The heat generation amount T _up is calculated according to the following equation (11).
(Heat generation amount T _up ) = {(torque phase time) × (torque phase average relative rotation speed) × (torque phase average transmission torque) + (inertia phase time) × (inertia phase average relative rotation speed) × (inertia phase average) Transmission torque)} / 1000 × (QT conversion coefficient) (11)
Here, the QT conversion coefficient is a coefficient for converting the unit into [° C.] because the unit becomes [J] when multiplied by time, relative rotational speed, and torque. At the time of unit conversion, in order to apply a coefficient after correcting [kJ], it is divided in advance by 1000.

  Next, the calculation of the DOWN burnout temperature in step S29 of FIG. 13 will be described with reference to the flowchart of FIG.

  In step S301, the vehicle speed after shifting to the (n-1) th stage is calculated.

  In step S302, the acceleration after the shift to the (n-1) th stage is calculated. The turbine rotational speed NT is obtained from the vehicle speed obtained in step S301, the turbine torque is obtained from the rotation-torque conversion map, and the acceleration is calculated based on the turbine torque.

  In step S303, the shift vehicle speed to the nth speed at the time of the n-1th speed is calculated. The shift vehicle speed to the nth speed at the time of the (n−1) th stage is a vehicle speed at which the upshift to the nth stage is determined, and is calculated with reference to the shift map.

  In step S304 (time estimation means), the shift vehicle speed arrival time at the n-th stage at the (n-1) -th stage is calculated. The shift vehicle speed arrival time at the n-th stage at the n-th stage is calculated based on the acceleration calculated at step S302.

In step S305, a heat dissipation coefficient is calculated. Radiation coefficient is calculated based on the heat generation amount T _up and the current clutch temperature Tc by a downshift is computed as the temperature after completion of the downshift increases higher.

In step S306, the heat radiation amount _Tdown until reaching the shift vehicle speed to the n-th stage at the n-1th stage is calculated. The heat dissipation amount _Tdown is calculated by multiplying the heat dissipation coefficient by the time required to reach the shift vehicle speed to the nth stage at the time of the (n-1) th stage.

In step S307, the down burnout temperature is calculated. Down burnout temperature is down burnout temperature as a base, and a value obtained by adding the temperature reduction caused by heat radiation amount T _down to the gear shift vehicle speed reaching the n stages when n-1 stage of the UP burnout temperature, low It is calculated as one of the two values.

Furthermore Here, the calculation of the normal DOWN shift predicted temperature increase T _INH is described with reference to a time chart of the flow chart and FIG. 21 in FIG. 18 in step S31 in FIG. 13. The time chart of FIG. 21 shows changes in (a) turbine rotational speed NT, (b) output rotational speed No (vehicle speed), (c) acceleration, (d) relative rotational speed, and (e) clutch transmission torque. . t1 to t2 are inertia phase target times.

  In step S401, the vehicle speed at the start of the inertia phase (FIG. 21B; t1) is calculated. The vehicle speed at the start of the inertia phase is calculated by adding the acceleration at the start of preprocessing multiplied by the preprocessing time to the vehicle speed at the start of preprocessing.

  In step S402, the turbine torque at the start of the inertia phase is calculated by obtaining the turbine rotation speed NT from the vehicle speed at the start of the inertia phase and the gear ratio, and referring to the rotation-torque conversion map based on the turbine rotation speed NT.

  In step S403, the transmission torque at the start of the inertia phase (FIG. 21 (e); t1) is calculated. The transmission torque at the start of the inertia phase is calculated by multiplying the turbine torque at the start of the inertia phase by the sharing ratio.

  In step S404, the vehicle speed at the end of the inertia phase (FIG. 21B; t2) is calculated. The vehicle speed at the end of the inertia phase is calculated based on the current acceleration, the preprocessing time, and the inertia phase target time.

  In step S405, the turbine torque at the end of the inertia phase is calculated. The turbine torque at the end of the inertia phase is calculated by obtaining the turbine rotation speed NT from the vehicle speed at the end of the inertia phase and the gear ratio, and referring to the rotation-torque conversion map based on the turbine rotation speed NT.

  In step S406, inertia torque transmission torque (FIG. 21 (e); t2) is calculated. The transmission torque at the end of the inertia phase is calculated by multiplying the turbine torque at the end of the inertia phase by the sharing ratio and the safety factor. The safety factor is a constant for determining the hydraulic pressure at the time of downshift and releasing the clutch, and is obtained based on the turbine torque and vehicle speed at the end of the inertia phase.

  In step S407, the inertia phase average transmission torque (FIG. 21E) is calculated. The inertia phase average transmission torque is calculated by dividing by 2 the sum of the transmission torque at the start of the inertia phase and the transmission torque at the end of the inertia phase. That is, it is calculated as an average value of the transmission torque at the start of the inertia phase and the transmission torque at the end of the inertia phase.

In step S408, the inertia phase average relative rotational speed (FIG. 21D) is calculated. The inertia phase average relative rotational speed is calculated according to the following equation (12).
(Inertia phase average relative rotation speed) = {A × (output rotation speed No at inertia phase start) + B × (turbine rotation speed NT at inertia phase start)} × π / 60 (12)
Here, A and B are relative rotation calculation constants and are obtained from the nomograph.

In step S409, the heat generation amount _Tup is calculated. The heat generation amount T _up is calculated according to the following equation (13).
(Heat generation amount T _up ) = {(Inertia phase time) × (Inertia phase average relative rotational speed) × (Inertia phase average transmission torque)} / 1000 × (QT conversion coefficient) (13)

The calculation of the predicted increase temperature T _INH for PYDOWN shift in step S35 of FIG. 13 is the same as the calculation of the predicted increase temperature T _INH for normal DOWN shift, but the inertia phase target time used in step S404. Is different from that for normal DOWN shift.

Will be described below with reference to the flowchart of FIG. 19 for the calculation of the second synchronization shift predicted temperature increase T _INH in the step S41 in FIG. 13.

  In step S501, the relative rotational speed between the turbine rotational speed NT and the output rotational speed No is calculated.

  In step S502, the target transmission torque of the released clutch is calculated.

  In step S503, a target shift time is calculated.

In step S504, the predicted heat generation amount _Tup is calculated. The predicted heat generation amount T _up is calculated by multiplying the relative rotational speed, the target transmission torque, and the target shift time.

  Next, the operation of the shift control device for an automatic transmission according to this embodiment will be described with reference to the time chart of FIG. Note that upshift and downshift mean a shift according to a normal shift mode in which shift shock is regarded as important unless otherwise described. FIG. 22 is a time chart showing a change in temperature of a certain clutch, and shows a state in which upshifting and downshifting are repeated between the n-th gear stage and the (n + 1) -th gear stage, and then heat is released.

When the UP shift is commanded at time t1, the predicted temperature increase T _INH for the UP shift is calculated, and the predicted temperature T _ES after the UP shift obtained by adding the current clutch temperature Tc to this is the UP burnout temperature. Since it is not exceeded, an upshift is performed.

When a downshift is commanded at time t2, a predicted increase temperature T _INH for DOWN shift is calculated, and the predicted temperature T _ES after downshift obtained by adding the current clutch temperature Tc to this is the DOWN burnout temperature. Since it has not exceeded, a downshift is performed.

Thereafter, upshift and downshift are repeated in the same manner, and when an upshift is determined at time t3, the predicted temperature T _ES after the upshift is calculated, and since this predicted temperature T _ES exceeds the UP burnout temperature, A PYUP shift which is a shift mode with a small amount of heat generation is performed. As a result, the heat generation amount _Tup of the clutch decreases, so that it is avoided that the clutch temperature exceeds the UP burnout temperature and burns out.

Thereafter, the clutch enters a steady engagement state and gradually dissipates heat. The heat release amount T _{down at} this time, that is, the temperature decrease gradient is determined based on the temperature difference between the temperature of the clutch immediately after the upshift performed after time t3 and the oil temperature T _OIL .

When the downshift is determined at time t4, the predicted temperature T _ES after the shift when the downshift is executed in the normal shift mode is calculated, and since this predicted temperature T _ES exceeds the DOWN burnout temperature, A predicted temperature T _ES after the PYDOWN shift which is a small shift mode is calculated. However, since the predicted temperature T _ES after the PYDOWN shift also exceeds the DOWN burnout temperature, execution of the downshift determined as a shift is prohibited.

When the downshift is determined again at time t5, the predicted temperature T _ES after the shift when the downshift is executed in the normal shift mode is calculated, and since this predicted temperature T _ES exceeds the DOWN burnout temperature, the PYDOWN shift is performed. The later predicted temperature T _ES is calculated. On the other hand, since the predicted temperature T _ES after the PYDOWN shift in the shift mode with a small amount of heat generation does not exceed the DOWN burnout temperature, the PYDOWN shift is performed.

Thereafter, the clutch is in a released steady state and gradually dissipates heat. The heat release amount T _{down at} this time, that is, the temperature decrease gradient, is determined based on the temperature difference between the clutch temperature immediately after the end of the downshift performed after time t5 and the oil temperature T _OIL .

After the time t5, when the clutch reset set time elapses or when the clutch temperature becomes equal to or lower than the oil temperature T _OIL , the clutch temperature is held as the oil temperature T _OIL (a constant value).

  As described above, according to the present embodiment, the burnout temperature for determining permission or prohibition of shifting is set to a different temperature depending on whether the type of shifting is upshift or downshift. Can be permitted and deterioration of drivability can be prevented (corresponding to claim 1).

  Also, the UP burnout temperature is set to a temperature higher than the DOWN burnout temperature, so it is possible to allow upshifts as much as possible, and downshifts are appropriately prohibited in consideration of upshifts after downshifts. (Corresponding to claim 2).

  Furthermore, since the DOWN burnout temperature is set based on the time until the upshift after the downshift that is calculated based on the current running state, the time until the upshift for preventing the engine overrev that occurs after the downshift. By taking into account, downshift can be allowed to the maximum, and deterioration of drivability can be further prevented (corresponding to claim 3).

Moreover, DOWN burnout temperature, since it is set lower than the maximum heat T _up by only the temperature rise UP burnout temperature occurring in the clutch when the PYUP shift, when determining whether to allow the prohibition of downshifting, after downshift The amount of heat generation T _{up due} to the upshift can be taken into consideration, and a reduction in the durability of the clutch can be prevented while allowing the downshift to the maximum extent (corresponding to claim 4).

Further, at the time of upshift, the temperature of the predicted shift at the end of the clutch is when more than the UP burnout temperature, performs PYUP shift calorific value T _up of the clutch is less than the normal UP shift. Here, if the upshift is prohibited and the engine rotational speed NE further increases, and if a forced upshift occurs to prevent overrev in this situation, the relative rotational speed of the clutch further increases, so heat is generated accordingly. The amount T _up also increases, and the gear shift is performed in a very severe situation. Therefore, when the temperature of the clutch at the time predicted shift termination as described above is not less than the UP burnout temperature, without disabling the UP shift, the decrease in the durability of the clutch by performing small PYUP shift heat generation amount T _up It can prevent appropriately (corresponding to claim 5).

Further, at the time of downshifting, the temperature of the predicted shift at the end of the clutch is when more than the DOWN burnout temperature, the time shift end in the case of performing the PYDOWN shift calorific value T _up of the clutch is less than the normal DOWN shift clutch When the predicted temperature does not exceed the DOWN burnout temperature, the PYDOWN shift is performed, so that the downshift can be allowed to the maximum and the deterioration of drivability can be further prevented (corresponding to claim 6). ).

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea.

It is a schematic diagram which shows the structure of the transmission control apparatus of the automatic transmission in this embodiment. It is a skeleton figure which shows the structure of the automatic transmission in this embodiment. It is a figure which shows the engagement state of the friction fastening element in each gear stage of the shift control apparatus of the automatic transmission in this embodiment. It is a figure which shows the shift map of the shift control apparatus of the automatic transmission in this embodiment. It is a block diagram which shows control of the transmission control apparatus of the automatic transmission in this embodiment. It is a figure explaining the clutch temperature initial value of the shift control apparatus of the automatic transmission in this embodiment. It is a figure explaining the characteristic of the clutch temperature of the shift control apparatus of the automatic transmission in this embodiment. It is a figure explaining the reset determination timer of the shift control apparatus of the automatic transmission in this embodiment. It is a time chart at the time of PYUP shift. It is a time chart at the time of PYDOWN shift. It is a flowchart which shows the calculation control of the clutch temperature of the transmission control apparatus of the automatic transmission in this embodiment. It is a flowchart which shows the calculation control of the thermal radiation amount at the time of fastening. It is a flowchart which shows the shift control of the shift control apparatus of the automatic transmission in this embodiment. It is a flowchart which shows the shift control of the shift control apparatus of the automatic transmission in this embodiment. It is a map which shows the continuous change mind shift permission frequency | count. It is a flowchart which shows the calculation control of the estimated temperature for UP shift. It is a flowchart which shows the calculation control of a DOWN burning temperature. It is a flowchart which shows the calculation control of the prediction temperature for normal DOWN shift. It is a flowchart which shows the calculation control of the predicted temperature for 2nd synchronous shifting. It is a time chart at the time of UP shift. It is a time chart at the time of DOWN shift. It is a time chart which shows the effect | action of the transmission control apparatus of the automatic transmission in this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Controller 3 Shift map 7 Automatic transmission 10 Input shaft or turbine shaft 12 Turbine rotating shaft rotational speed sensor 13 Output shaft rotational speed sensor 14 Oil temperature sensor 15 First clutch (friction element)
17 Second clutch (friction element)
19 Third clutch (friction element)
22 First brake (friction element)
23 Second brake (friction element)
101 Current temperature calculation means (current thermal load calculation means)
102 Predicted rising temperature calculation means (heat generation amount prediction means)
103 Predicted temperature calculation means (thermal load prediction means)
104 Shift prohibition switching means (shift control means)
105 Heat generation amount calculation means 106 Heat release amount calculation means 107 Disengagement transient heat generation amount calculation means 108 Disengagement transient heat generation amount calculation means 109 Comparison means 110 Threshold storage means 111 UP shift predicted temperature increase calculation means 112 Normal DOWN shift prediction Rise temperature calculation means 113 PYDOWN shift predicted increase temperature calculation means 114 Second synchronous shift predicted increase temperature calculation means 115 Continuous change mind shift permission frequency calculation means

Claims (6)

In a shift control device for an automatic transmission that performs a shift from a current shift stage to a target shift stage by selectively engaging or releasing a plurality of friction elements,
Current thermal load calculating means for calculating a current thermal load state of the friction element;
A heat generation amount prediction means for predicting a heat generation amount in the friction element when the shift is performed before the start of the shift;
Thermal load predicting means for predicting a thermal load state at the end of shifting of the friction element based on a current thermal load state of the friction element and a heat generation amount predicted by the heat generation amount prediction means;
When the thermal load state at the end of the shift predicted by the thermal load predicting means becomes a predetermined state, the shift mode is changed so that the amount of heat generated by the friction element is smaller than when the shift is not performed. Shift control means for performing or prohibiting the shift,
The shift control device for an automatic transmission, wherein the predetermined state is set to be different depending on whether the shift is upshift or downshift. The predetermined state is set to a first predetermined state when the shift is an upshift, and is set to a second predetermined state when the shift is a downshift.
The shift control device for an automatic transmission according to claim 1, wherein the first predetermined state is a state in which a thermal load state is higher than the second predetermined state. When the shift is a downshift, it comprises time estimation means for estimating the time until the upshift after the downshift based on the current running state before the start of the shift,
The shift control device for an automatic transmission according to claim 2, wherein the second predetermined state is set based on a time estimated by the time estimation means.   The second predetermined state includes only the thermal load state corresponding to the maximum heat generation amount generated in the friction element in the case of an upshift according to the shift mode changed so that the heat generation amount of the friction element is reduced. 3. The shift control device for an automatic transmission according to claim 2, wherein the thermal load state is set to be lower than the predetermined state.   When the shift is an upshift, and the thermal load state at the end of the shift predicted by the thermal load predicting means is the first predetermined state, the amount of heat generated by the friction element is less than that when it is not. The shift control apparatus for an automatic transmission according to any one of claims 2 to 4, wherein the shift is performed by changing a shift mode so as to be reduced. When the shift is a downshift, and when the thermal load state at the end of the shift predicted by the thermal load predicting means is the second predetermined state, the amount of heat generated by the friction element is less than that when the shift is not. The amount of heat generated in the friction element when a shift is performed in a reduced speed change mode is predicted, and the speed of the friction element is changed based on the newly predicted amount of heat generation and the current thermal load state of the friction element. Predict the thermal load condition at the end,
6. The shift according to any one of claims 2 to 5, wherein the shift is performed in the changed shift mode when the newly predicted thermal load state at the end of the shift is not the second predetermined state. The shift control device for an automatic transmission according to the item.