JP2002310288A - Lockup control device for automatic transmission - Google Patents

Abstract

(57) [Summary] [PROBLEMS] As a measure for preventing engine stall when sudden deceleration occurs in a lock-up state, this measure can be performed without causing the torque converter to slip, thereby preventing fuel efficiency improvement from being sacrificed by fuel cut. I do. SOLUTION: A controller 9 controls the speed of the automatic transmission 2 through solenoids 6 and 7 and locks up the torque converter 3 through a solenoid 8 based on a throttle opening TH and an output rotation speed No. During coasting in which the throttle opening TH is close to 0 in the lock-up state, the controller 9 sets the torque converter 3 via the solenoid 8 to the smallest coasting traveling engagement capacity in a range where no slip occurs. Controller 9 when sudden deceleration occurs
Releases the lock-up, but the small lock-up capacity accomplishes this quickly to prevent engine stall. Note that the coasting engagement capacity is calculated from the reverse drive torque detection value of the engine, and this detection value is corrected by an increase or decrease in torque according to the operation or non-operation of the engine drive auxiliary machine, thereby contributing to the calculation of the coasting engagement capacity. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention appropriately controls a lock-up state in which an input / output element is directly connected to a torque converter inserted into a transmission system of an automatic transmission during coasting including deceleration of a vehicle. The present invention relates to a lockup control device.

[0002]

2. Description of the Related Art In order to improve fuel efficiency by improving transmission efficiency, an automatic transmission uses a torque converter under a vehicle operating condition in a lock-up region where a torque increasing function and a torque fluctuation absorbing function are not required. In this case, a lock-up type is adopted in which a lock-up state in which input / output elements are directly connected is adopted.

Conventionally, lock-up control of this type of torque converter is performed as described in, for example, an automatic transmission described in "NISSAN RE4R01A Full-range Electronically Controlled Automatic Transmission Maintenance Manual" issued by the present applicant. 16 shows the lock-up ON line with a two-dot chain line and lock-up OFF
As exemplified by the one-dot chain line, in any one of the vehicle operating states in the lockup (L / U) region and the converter (C / V) region defined by the throttle opening TH (engine operation load) and the vehicle speed V. In the lock-up region, the torque converter is set to a lock-up state in which the input / output elements are directly connected by opening the lock-up clutch. It is customary to make the converter state in which the direct connection is broken.

In order to improve the fuel efficiency by locking up the torque converter, it is necessary to expand the lock-up region so that the torque converter is locked up to a low load operation and a low vehicle speed as much as possible. Is determined, for example, as shown in FIG.

On the other hand, as a device for improving the fuel efficiency of the vehicle, power from the so-called coasting engine including deceleration by releasing the accelerator pedal is not necessary, so that fuel supply to the engine is stopped during this period. There is a fuel cut device. In this device, when the engine speed decreases to a set speed (fuel recovery speed), fuel cut is stopped and fuel supply is restarted (fuel recovery) in order to prevent engine stall. In such a device, delaying the decrease in the engine speed during coasting results in a longer fuel cut time and a greater effect of improving fuel efficiency. For this reason, generally, in a vehicle equipped with an engine with a fuel cut device, the throttle opening T
It is customary to bring the torque converter into a lockup state during coasting with H set to 0/8.

[0006]

For these reasons, the torque converter is often brought into a lock-up state in which the input and output elements are directly connected during coasting of the vehicle. When braking with the brake pedal depressed, especially on low friction roads, the wheels are suddenly stopped rotating, so the lock-up release, which cannot escape a relatively large response delay of the torque converter, cannot catch up with this and drives the wheels. There has been a problem that a harmful effect such as a stop of the combined engine is concerned.

Conventionally, as described in Japanese Patent Application Laid-Open No. 4-370465, when a brake pedal is depressed during coasting,
A technology is proposed that switches the torque converter in the lock-up state to a slip control state in which slip occurs to allow relative rotation between input and output elements, and releases the lock-up of the torque converter during sudden deceleration with the brake pedal depressing force increased. Have been.

According to this technique, although the problem of engine stall due to a delay in response to lock-up release can be solved, the torque converter immediately slips when the vehicle is coasted despite not being subjected to sudden braking.
The following problems arise. In other words, the slip of the torque converter causes the engine speed to be reduced by the amount of the slip, so that the fuel cut has to be stopped and the fuel must be recovered sooner, and the effect of improving the fuel economy by the fuel cut is diminished. In other words, the above prior art is not perfect because it is a measure to prevent engine stall at the expense of the fuel efficiency improvement effect of fuel cut.

The present invention is based on the fact that the response delay of the lock-up release changes according to the engagement capacity of the lock-up clutch as shown in FIG. 17, that is, as shown in FIG. 18, the lock-up release command instant t _1. lockup clutch engagement capacity from the solid line in the immediately preceding dotted, as it drops from the dotted line to the one-dot chain line, the lock-up shows the time courses in the same corresponding line release pressure P _R and the lock-up engagement pressure P _a of Based on the fact that response delays ΔT ₁ , ΔT ₂ , ΔT ₃ until lock-up release completed at the moment of intersection are reduced, the above-mentioned problem that the fuel cut effect of fuel cut is reduced is not a sudden deceleration. This is because the torque converter slips immediately after coasting, and lock-up occurs during coasting without sudden deceleration. The clutch engagement capacity is set to the smallest engagement capacity within a range that does not cause slippage of the torque converter, and thereby the engine accompanying the response delay of lock-up release without sacrificing the fuel efficiency improvement effect of fuel cut. The purpose is to realize stall prevention.

[0010]

According to the present invention, there is provided a lock-up control device for an automatic transmission according to the present invention, wherein the transmission includes the torque converter with the lock-up clutch in a transmission system. Assuming a vehicle equipped with a vehicle, coasting detection means for detecting during coasting including deceleration operation of the vehicle, sudden deceleration detection means for detecting a large deceleration greater than or equal to a set value of the vehicle, In response to the signal, while the vehicle deceleration is less than the set value during the coasting, the engagement capacity of the lock-up clutch is set to the smallest coasting engagement capacity within a range that does not cause relative rotation between the torque converter input / output elements. And a coast-up lock-up capacity control means for controlling.

The inertia running lock-up capacity control means includes a reverse driving torque detecting means for detecting a reverse driving torque of the prime mover in a forward gear of the automatic transmission, and the inertia running torque based on the reverse driving torque detected by the means. And a coasting lock-up capacity calculating means for calculating the running engagement capacity. The reverse drive torque detecting means is configured to correct the reverse drive torque detection value of the prime mover by an increase or decrease in the torque of the accessory according to the operation or non-operation of the auxiliary machine to be driven by the prime mover.

A lock-up control device for an automatic transmission according to the present invention can be configured as described in claim 2 so as to achieve the above object. That is, the configuration is substantially the same as the above, but the reverse drive torque detecting means is configured to correct the reverse drive torque detection value of the prime mover according to the cooling water temperature of the prime mover instead of the above.

[0013]

According to the first aspect of the present invention, the inertia traveling lock-up capacity control means detects that the vehicle is coasting, including the deceleration operation of the vehicle, while the inertia traveling detection means detects that the vehicle is suddenly decelerating. While the large deceleration greater than the set value is not detected, that is, while the vehicle deceleration is less than the set value while the vehicle is coasting, the engagement capacity of the lock-up clutch is set so that relative rotation does not occur between the torque converter input and output elements. To control to the smallest coasting traveling engagement capacity.

By the way, during coasting in which the vehicle deceleration is less than the above set value, the engagement capacity of the lock-up clutch is controlled to the smallest coasting engagement capacity within a range that does not cause relative rotation between the torque converter input / output elements. From that
Then, when the vehicle deceleration becomes equal to or higher than the above set value, the disengagement of the lock-up clutch can be completed promptly with a small response delay, eliminating the concern that the prime mover will stop despite sudden deceleration. I can do it. Such an effect is not achieved by the slip control of the torque converter, but is obtained while maintaining the lock-up state of the torque converter. There is no adverse effect such that the fuel cut time is shortened and the fuel efficiency improvement effect of the fuel cut is sacrificed.

Further, in the present invention, the reverse drive torque detecting means detects the reverse drive torque of the prime mover in the preceding stage of the automatic transmission, and the coasting lockup capacity calculating means calculates the reverse drive torque from the reverse drive torque detected by the means. Since the coasting engagement capacity is calculated, the coasting engagement capacity is adapted to the actual situation, and the engagement capacity control of the lock-up clutch during coasting is performed so that the above-described operation and effect can be reliably achieved. Can be something.

Further, in the present invention, the reverse drive torque detecting means corrects the reverse drive torque detection value of the prime mover by an amount corresponding to the increase or decrease of the torque by the accessory according to the operation or non-operation of the auxiliary machine to be driven by the prime mover. Therefore, the reverse drive torque can be accurately detected without being affected by the operation and non-operation of the auxiliary equipment, and the control of the engagement capacity of the lock-up clutch during coasting is affected by the operation and non-operation of the auxiliary equipment Without doing so, it is possible to achieve the above-described effects more reliably.

According to the second aspect of the present invention, the reverse drive torque detecting means corrects the reverse drive torque detection value of the prime mover in accordance with the cooling water temperature of the prime mover. The drive torque can be accurately detected, and the control of the engagement capacity of the lock-up clutch during coasting can be performed more reliably without being affected by the temperature change of the prime mover. can do.

[0018] Regardless of which of the configuration described in claim 1 or the configuration described in claim 2 is adopted, the brake detecting means detects that the vehicle is being braked, as described in claim 3.
Further, when the accelerator operation detecting means detects that the accelerator pedal is depressed, the lock-up clutch is forcibly released by the lock-up forcible releasing means. At the time of a driving operation in which the accelerator pedal is depressed while braking as described above, since the detection by the coasting detection unit cannot be performed, the engagement capacity of the lockup clutch is determined by the coasting lockup capacity control unit before the rapid deceleration. Although it is not possible to expect the effect of making the inertia traveling engagement capacity the smallest in a range in which relative rotation does not occur between the torque converter input and output elements, the corresponding effect cannot be obtained. Since the lock-up clutch is forcibly released in advance as described above, the occurrence of engine stall can be prevented.

When the coasting lock-up capacity control means controls the engagement capacity of the lock-up clutch in accordance with a predetermined command value, the coasting detection means detects the command value. During a set time after detecting the transition to the coasting, it is preferable to set a value corresponding to the release of the lock-up clutch. In this case, the engagement capacity of the lock-up clutch can be promptly reduced to the minimum coasting engagement capacity within a range in which relative rotation does not occur between the torque converter input / output elements. Takes a considerable amount of time,
There is a concern that the above-described effects cannot be expected even if a sudden deceleration is detected before the engagement capacity is reduced. However, this concern can be eliminated in the present configuration.

Further, as set forth in claim 5, the time measuring means measures the time from the end of the control by the coasting lock-up capacity control means to the next coasting. It is preferable to shorten the set time in which the command value is set to a value corresponding to the release of the lock-up clutch. In this way, when the time from the end of the control by the coasting lock-up capacity control means to the next coasting is short, the engagement capacity of the lock-up clutch is still small before the engagement capacity of the lock-up clutch returns to the original state. In the configuration according to the fourth aspect, the capacity control command value is set to a value corresponding to the release of the lock-up clutch, and the engagement capacity of the lock-up clutch tends to be too low to deteriorate fuel efficiency. Then it can be resolved.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a lockup control device for an automatic transmission according to an embodiment of the present invention. In this figure, reference numeral 1 denotes an engine as a prime mover, and 2 denotes an automatic transmission. The automatic transmission 2 receives the power of the engine 1 via the torque converter 3, changes the input rotation at a gear ratio according to the selected shift speed, and transmits the input rotation to the output shaft 4.

Here, the automatic transmission 2 turns on and off the shift solenoids 6 and 7 in the control valve 5.
The gear ratio is determined by the combination of the torque converter 3 and the torque converter 3 controls the duty ratio of the lock-up solenoid 8 in the control valve 5 so that the converter state is not directly connected between the input and output elements or the lock-up between the input and output elements is not shown. It can be brought into a lockup state directly connected by a clutch. The lock-up solenoid 8 puts the torque converter 3 into a converter state by releasing the lock-up clutch when the drive duty D is 0%, and locks the torque converter 3 when the drive duty D is 100% by engaging the lock-up clutch. Shall be

ON / OFF of shift solenoids 6 and 7;
And the drive duty D of the lock-up solenoid 8
Are controlled by a controller 9. The controller 9 receives a signal from a throttle opening sensor 10 for detecting a throttle opening TH of the engine 1,
From the engine rotation sensor 11 that detects the rotation speed Ne of the automatic transmission 2, the input rotation speed (the torque converter 3
Output rotation speed) Nt turbine speed sensor 12 for detecting Nt
, A signal from a transmission output rotation sensor 13 for detecting the number of rotations of the transmission output shaft 4, and a transmission operating oil temperature C
, And a signal B from a brake switch 15 that is turned on when the brake pedal is depressed.

Although not shown, the controller 9 performs the following shift control based on these input information by a well-known calculation. That is, in the shift control, the controller 9 obtains the optimum gear position for the current driving state from the throttle opening TH and the vehicle speed V obtained from the transmission output rotation speed No, for example, from table data by a lookup method. The shift solenoid 6, so that the optimal gear position is selected
7 is turned on and off to perform a predetermined shift.

Next, the lock-up control will be described. In this lock-up control, it is assumed that the controller 9 repeatedly executes the main routine of FIG. 2 by a periodic interruption every Δt = 10 msec. First, at step 21, the throttle opening TH, the transmission output rotation speed No, and the transmission operating oil temperature C are read. In the next step 22, the vehicle speed V is calculated from the transmission output rotation speed No, and is set to V (NEW).
(OLD) and the difference ΔV between the current vehicle speed calculation value V (NEW) and the vehicle deceleration are obtained.

In step 23, for example, a lock-up vehicle speed diagram (L / U indicates a lock-up region, C /
Based on the throttle opening TH and the above-mentioned vehicle speed V, it is determined from the table data corresponding to the converter area (V is the converter area) which of the lock-up area L / U and the converter area C / V is running. Determine. In the case of the converter area C / V, the drive duty D of the lock-up solenoid 8 is set to 0% in step 24.
Is output to the lock-up solenoid 8 at step 30 to bring the torque converter 3 into the converter state as required by opening the lock-up clutch and as usual.

When it is determined in step 23 that the lock-up area is L / U, step 2 corresponds to the coasting detection means.
In 5, it is determined whether or not the vehicle is coasting including deceleration based on whether or not the throttle opening TH is less than the minute set value THs. When it is determined that the vehicle is not coasting, the drive duty D of the lock-up solenoid 8 is set to 100% in step 26 and is output to the lock-up solenoid 8 in step 30 to thereby connect the torque converter 3 to the lock-up clutch. Tighten to lock-up as required and normal. Although not shown in step 25 as the coasting detection means instead of the above, it is also possible to determine whether or not the vehicle is coasting based on a signal from an idle switch that is turned on when the accelerator pedal is released. Needless to say.

If it is determined in step 25 that the vehicle is coasting, step 27 corresponding to the rapid deceleration detecting means is performed.
It is determined whether or not rapid deceleration is performed based on whether or not the vehicle deceleration ΔV is equal to or greater than the set value ΔVs. If it is not sudden deceleration, in step 28 corresponding to the coasting lockup capacity control means, the coasting lockup clutch engagement capacity is determined, and the corresponding drive duty Dc% of the lockup solenoid 8 is calculated. This is set as the lock-up solenoid drive duty D.

This process is as shown in FIG.
First, in step 61 corresponding to the reverse drive torque detecting means,
The reverse drive torque T applied to the engine during coasting is searched from the engine speed Ne on the basis of table data previously obtained through experiments and the like illustrated in FIG. Then, in step 62, it calculates a lockup release pressure P _r just balances the reverse drive torque T. Here, the lock-up engagement pressure acting constantly lockup clutch piston in a direction to oppose the lock-up release pressure of P _A, the pressure receiving area of the lockup clutch piston and S, and the facing friction coefficient mu, When the average radius of the facing is R, the lock-up release pressure P _r just balances the reverse drive torque _{T, P r = P a - (} T / S · μ · R) is represented by and the lock-up engagement pressure P _Since it is known that A can change as shown in FIG. 5 according to the line pressure controlled by the line pressure solenoid drive duty, which is an internal signal of the transmission controller 9, and can be searched, the reverse drive torque T exactly balanced lockup release pressure P _r can be calculated by calculating the above equation.

[0030] At step 63 corresponding to the next coasting lockup capacity calculation means, is calculated by the above, release target lockup by subtracting a predetermined value δ from the lock-up release pressure P _r just balances the reverse drive torque T determine the pressure P _R. Here reason for subtracting a predetermined value δ is in the lock-up release pressure P _r just balanced with the reverse drive torque T, since it may not be possible to keep the slip of the torque converter to completely 0, with a margin This is because there is a need to set the lock-up release pressure P _R.

[0031] In the next step 64, the duty Dc for achieving the target lockup release pressure P _R above,
For example, a search is performed based on the table data corresponding to FIG. 6, and this is set as the lock-up solenoid drive duty D. D = Dc% thus determined corresponds to the smallest lock-up clutch engagement capacity (coasting engagement capacity) within a range in which the torque converter 3 does not slip.

Thereafter, when it is determined in step 27 of FIG. 2 that rapid deceleration is to be performed, the drive duty D of the lock-up solenoid 8 is set to 0% in step 29 corresponding to the lock-up releasing means for rapid deceleration, and this is set in step 30. To output to the lock-up solenoid 8. As a result, the torque converter 3 is released from the lock-up and enters the converter state, and it is possible to prevent the engine 1 from being stopped by the braked drive wheels during the sudden deceleration of the vehicle.

The engagement capacity of the lock-up clutch is controlled during coasting before the vehicle suddenly decelerates, so that the engagement capacity of the lock-up clutch becomes the smallest engagement capacity for coasting as long as the torque converter 3 does not slip as described above with reference to FIG. from, that from the migration instant t ₁ to coasting as shown in the time chart of FIG. 9, until the sudden deceleration instant t ₃ when accompanied by a braking operation of the instant t _2, the lock-up release pressure P by the capacity reduction control of the _{since R} is reduced to P _RC corresponding to D = Dc%, which becomes the above-mentioned lock-up release ending instant t ₄ when crossing the lockup pressure P _a is rapidly completed, the lock It is possible to reduce the response delay ΔT _{C of the} release of the up, and it is possible to eliminate the concern that the engine stall occurs.

According to this control, the above-described operation and effect can be achieved without causing the torque converter 3 to slip. Therefore, the fuel cut time is shortened due to the decrease in the engine speed due to the slip, and the fuel cut is performed. The problem of sacrificing the fuel efficiency improvement effect caused by this is not caused.

In the present embodiment, the reverse drive torque T of the engine is obtained by searching, but it can be directly detected by a torque sensor. However, needless to say, a search method that does not require addition of a sensor and is advantageous in terms of cost is better.

By the way, when a torque sensor is not used,
Naturally, the retrieved reverse drive torque T causes an error between the actual value due to the operation and non-operation of the engine drive auxiliary equipment such as the air conditioner, the power steering device, and the alternator, and the engine coolant temperature. It is preferable to perform correction for correcting this error. If an air conditioner is taken as an example of the auxiliary equipment, the driving load of the air conditioner does not change much depending on the engine speed Ne as shown in FIG. Only OFF is detected, and when ON, an air conditioner driving load is added to the retrieved reverse drive torque T to contribute to the control in FIG. 3, and such correction is not performed when OFF. Further, the engine cooling water temperature is substantially the same as the transmission working oil temperature C, and the reverse drive torque changes as illustrated in FIG.
In anticipation of this change, the reverse drive torque search value T is corrected according to the temperature C.

In the above-described embodiment,
In step 25 of FIG. 2, the throttle opening TH is set to the set opening T.
When it becomes less than Hs, it is determined that the vehicle is coasting, and the above-described lock-up clutch engagement capacity control during the coasting is performed. For example, it is possible to depress the brake pedal while depressing the accelerator pedal using both feet. When the abnormal operation is performed, the lock-up clutch engagement capacity control during the coasting cannot be performed, and the above-described operation and effect cannot be obtained.

The operation of the above embodiment at the time of such an abnormal operation will be described with reference to FIG. 11 corresponding to FIG. While depresses the accelerator pedal, the instant t ₂ when an abnormality operation depresses the brake pedal, not give the lockup clutch engagement capacity control during coasting is initiated, the vehicle deceleration Δ
V is deceleration lock-up release control as usual made instantaneously t ₃ when reaching the set deceleration .DELTA.Vs, with the lock-up engagement pressure P _A as indicated by a dotted line decreases, the lock-up release pressure as indicated by a dotted line P _R is increased, the deceleration lock-up release instantaneously t ₄ when these pressures intersect is completed. Thus, it now too late lockup release time t ₄ gives rise to an engine stall as is clear from aging indicated by the dotted line in the engine rotational speed Ne.

FIG. 10 shows an embodiment which solves this problem, and is an alternative to FIG. In FIG. 10, steps for performing the same processing as in FIG. 2 are denoted by the same reference numerals. In the present embodiment, in step 21, the brake switch signal B is additionally read and a step 71 is added between step 25 corresponding to the accelerator operation detecting means and the next step 26. In step 71 corresponding to the brake detecting means, it is checked whether or not the brake is being depressed by depressing the brake pedal, based on whether the brake switch signal B is ON or OFF. If braking is not being performed, control is advanced to step 26 to execute the same control as in FIG. 2, but if it is determined that braking is being performed, control is advanced to step 24, and the corner lock-up is released. Issue a command. Therefore, Step 24 is performed in the case of this embodiment.
This corresponds to lock-up forced release means.

FIG. 11 will be described according to this control.
With the brake pedal depressed while pressing the accelerator pedal.
The instant t when an abnormal operation is performed_Two And as shown by the solid line
Lock-up fastening pressure P_A Decreases and is indicated by a solid line.
Lock-up release pressure P _R Rise and these pressures
The intersecting lock-up release instant is the above instant t._Four than
Can be faster. Therefore, depress the accelerator pedal
When the brake pedal is depressed and abnormal operation is performed,
The instant t at which the vehicle deceleration ΔV becomes equal to or greater than the set deceleration ΔVs_Three 
Lock-up can be released when it is not far behind
And the engine speed Ne is indicated by a one-dot chain line.
Engine stall does not occur
Can be prevented.

By the way, the decrease control of the lock-up clutch engagement capacity to be performed during coasting in the embodiments described above, proceeds by the traffic of the vent of lock-up engagement pressure P _A, and the supply of the lock-up release pressure P _R to be, as it is apparent from the lock-up clutch engagement capacity change between the coasting initial instant t ₁ in Figure 15 to sudden deceleration instant t _2, inevitably the progress of the control is slightly delayed. Therefore, the rapid deceleration from coasting start instant t ₁ instant t ₂
In the operation in which the time until the lock-up clutch engagement speed is short, the lock-up solenoid driving duty D
= Dc%, the lock-up release command is issued before the target capacity for coasting decreases, and this lock-up release is delayed with respect to rapid deceleration. The effect may not be sufficiently achieved.

FIG. 12 shows an embodiment in which such a problem is solved. This control program is executed only when the torque converter is locked up and before the vehicle is suddenly decelerated by the brake operation. Shall be shown. First, at step 81, the throttle opening T
Whether or not the vehicle is coasting is checked based on whether or not H is less than the set opening THs. If the vehicle is not coasting, the drive duty D = 100% is maintained in step 82 to maintain the lock-up state.

If the vehicle is coasting, in step 83, a timer TM1 for measuring the elapsed time after the transition to the coasting operation is provided.
It is determined whether or not the minute set time indicated by ΔT _R in FIG. 14 has been reached. As shown in FIG. 14, the drive duty D is changed to 0% corresponding to lock-up release in step 84 until the set time ΔT _R elapses from the coasting instant t _1.
Then, in step 84, the drive duty D is set to Dc% obtained in the same manner as in each of the above embodiments. According to this control, the drive duty is rapidly reduced during the minute set time ΔT _R , so that the lock-up clutch engagement capacity is quickly changed to D =
It can be reduced to the target capacity for coasting corresponding to Dc%. Accordingly, even when the operation of performing rapid deceleration from coasting initial instant t ₁ to instant t ₂ without placing between large, yet the lock-up clutch engagement capacity in the lock-up release command when that response to the rapid deceleration corresponding to D = Dc% It is possible to solve the problem that the lock-up release is delayed with respect to the rapid deceleration and the operation and effect aimed at by the present invention cannot be sufficiently achieved. .

FIG. 13 shows a further improvement of FIG.
In this modified example, a step 86 corresponding to the time measuring means is inserted between steps 81 and 83, and here, the next inertia starts after the end of the coasting lock-up clutch engagement capacity control in step 85 (instantaneous t _{2 in} FIG. 14). It is determined whether or not the time TM2 up to the instant of the traveling shift is less than the set time ΔT _I. If TM2 ≧ ΔT _I , the control proceeds to step 83 to perform the same control as described above with reference to FIG.
If M2 <ΔT _I , the control proceeds to step 85, and the drive duty sudden decrease operation during the minute set time ΔT _R in step 84 is not performed.

To explain the reason, when TM2 <ΔT _I , since the engagement capacity of the lock-up clutch is still small before returning to the original state, it is necessary to perform the drive duty sudden decrease operation during the minute set time ΔT _R. This is because the engagement capacity of the lock-up clutch becomes too low, which tends to deteriorate fuel efficiency.

In this case, when TM2 <ΔT _I , the drive duty sudden decrease operation is not performed during the minute set time ΔT _{R.
As the} time becomes shorter than _{I, the} minute setting time ΔT _R may be shortened. In this case, it is preferable to perform a control that further matches the actual situation. Then, when TM2 becomes shorter than a certain extent, ultimately to the [Delta] T _R = 0, and is not performed the drive duty rapid reduction operation during the minute setting time [Delta] T _R.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a lockup control device according to the present invention.

FIG. 2 is a flowchart of a main routine showing lock-up control performed by a transmission controller according to the embodiment.

FIG. 3 is a flowchart showing a calculation program in a case where a coast-up lock-up capacity is obtained by calculation in the embodiment.

FIG. 4 is a diagram showing a relationship between a reverse drive torque searched in the embodiment and an engine speed.

FIG. 5 is a diagram showing a relationship between a lock-up engagement pressure searched in the embodiment and a line pressure solenoid drive duty.

FIG. 6 is a diagram showing a relationship between a lock-up solenoid drive duty searched in the embodiment and a target lock-up release pressure.

FIG. 7 is a characteristic diagram of an air conditioner driving load that affects a reverse driving torque searched in the embodiment.

FIG. 8 is a diagram showing a relationship between a reverse driving torque searched in the embodiment and an engine cooling water temperature.

FIG. 9 is an operation tie time chart of the lockup control device in the embodiment shown in FIGS. 1 to 8;

FIG. 10 is a flowchart of a main routine showing lock-up control according to another embodiment of the present invention.

FIG. 11 is an operation tie time chart in the embodiment.

FIG. 12 is a main part flowchart showing an improvement example of the embodiment.

FIG. 13 is a main part flowchart showing a further improved example of the embodiment.

FIG. 14 is an operation tie time chart according to the embodiment shown in FIG. 12;

FIG. 15 is an operation tie-time chart used to explain inconvenience when the example of FIGS. 12 and 13 is not improved;

FIG. 16 is a region diagram illustrating a lockup region of the automatic transmission.

FIG. 17 is a diagram showing a relationship between a lock-up clutch engagement capacity and a response delay of lock-up release.

FIG. 18 is an operation tie time chart showing a relationship between a lock-up clutch engagement capacity and a response delay of lock-up release.

[Explanation of symbols]

 Reference Signs List 1 engine (motor) 2 automatic transmission 3 torque converter 5 control valve 6 shift solenoid 7 shift solenoid 8 lock-up solenoid 9 controller 10 throttle opening sensor 11 engine rotation sensor 12 turbine rotation sensor 13 transmission output rotation sensor 14 oil temperature sensor 15 Brake switch

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Noboru Hattori, Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Hidesaku Katakura 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa, Nissan Motor Co., Ltd. 72) Inventor Naoaki Higashijima 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in Nissan Motor Co., Ltd. (reference) 3J053 CA02 CB09 CB12 DA02 DA04 DA06 DA07 EA01

Claims (5)

[Claims] 1. A vehicle equipped with an automatic transmission having a torque converter in a transmission system which can be brought into a lock-up state in which an input / output element is directly connected by a lock-up clutch, and detects during coasting including deceleration operation of the vehicle. In response to signals from these two detection means, the vehicle deceleration is less than the set value while coasting. And a coasting lockup capacity control means for controlling the engagement capacity of the lock-up clutch to the smallest coasting engagement capacity within a range that does not cause relative rotation between the torque converter input / output elements. Lock-up capacity control means includes reverse drive torque detection means for detecting reverse drive torque of the prime mover in the forward gear of the automatic transmission; Coasting lock-up capacity calculating means for calculating the coasting engagement capacity from the detected reverse drive torque, the reverse drive torque detecting means for activating or deactivating an auxiliary machine to be driven by the prime mover. A lock-up control device for an automatic transmission, wherein the reverse drive torque detection value of the prime mover is corrected according to the increase or decrease of the torque by the auxiliary machine. 2. A vehicle equipped with an automatic transmission having, in a transmission system, a torque converter capable of establishing a lock-up state in which an input / output element is directly connected by a lock-up clutch in a transmission system, and detects during coasting including deceleration operation of the vehicle. In response to signals from these two detection means, the vehicle deceleration is less than the set value while coasting. And a coasting lockup capacity control means for controlling the engagement capacity of the lock-up clutch to the smallest coasting engagement capacity within a range that does not cause relative rotation between the torque converter input / output elements. Lock-up capacity control means includes reverse drive torque detection means for detecting reverse drive torque of the prime mover in the forward gear of the automatic transmission; A coast-up lock-up capacity calculating means for calculating the coasting engagement capacity from the detected reverse drive torque, the reverse drive torque detecting means detecting a reverse drive torque of the prime mover according to a cooling water temperature of the prime mover. A lockup control device for an automatic transmission, wherein the lockup control device is configured to correct a value. 3. The lock-up control device according to claim 1, wherein the brake detection means detects that the vehicle is being braked, and the accelerator operation detection means detects that the accelerator pedal of the vehicle is depressed. A lock-up control device for an automatic transmission, further comprising lock-up forcible release means for forcibly releasing the lock-up clutch when braking detection and accelerator pedal depression detection by these means are simultaneously performed. 4. The lock-up control device according to claim 1, wherein the coast-up lock-up capacity control means controls the engagement capacity of the lock-up clutch according to a predetermined command value. Wherein the command value is set to a value corresponding to the release of the lock-up clutch during a set time after the coasting detection means detects the shift to the coasting of the vehicle. Lock-up control device. 5. The lock-up control device according to claim 4, further comprising a time-measuring means for measuring a time from the end of the control by the coasting lock-up capacity control means to the next coasting. A lock-up control device for an automatic transmission, wherein the set time in which the command value is set to a value corresponding to the release of the lock-up clutch is shortened as the measurement time is shortened.