JPH0792145B2 - Automatic transmission control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling an automatic transmission mounted on a vehicle, and more particularly to directly connecting an output shaft of an engine and an input shaft of a speed change gear mechanism. The present invention relates to a device for changing and controlling an operating region of a lockup mechanism.

(Prior Art) Conventionally, as a control device for changing the lock-up operation region of an automatic transmission, as shown in, for example, Japanese Patent Laid-Open No. 56-138559, the cooling water temperature of the engine is detected, When the temperature of the cooling water is low, the lockup pattern, which is the basis for activating and deactivating the lockup mechanism, is shifted to the high-speed side of the engine, thereby expanding the lockup release area when the engine is cold to increase the engine. It is known that the load is reduced.

(Problem to be Solved by the Invention) By the way, a state in which the engine is idle to cope with an external load such as an electric load for driving a generator or a load for driving a compressor of an air conditioner (air conditioner) Then, when the automatic transmission is locked up, the driving force of the engine for running the vehicle decreases due to the direct connection between the output shaft of the engine and the input shaft of the transmission.
There is a problem that the drivability of the vehicle is sacrificed.

Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to utilize the concept of the conventional technique described above to perform automatic gear shifting in a state where an external load acts on the engine. By limiting the operating region of the lockup characteristic of the machine in the direction of reducing the lockup characteristic, it is possible to reduce the decrease in the engine driving force with respect to the vehicle running caused by the action of the external load by releasing the lockup.

(Means for Solving the Problem) In order to achieve the above object, the solution means of the present invention is
As shown in the figure, the output shaft 2 of the engine 1 and the automatic transmission 3
Between the input shaft 5 of the speed change gear mechanism 4 in FIG.
A torque converter 7 having a lock-up clutch 6 directly connected to the torque converter 7 is provided, and a load sensor 91 for detecting a load state of the engine 1 by a throttle opening and the like, a turbine speed of the torque converter 7, a vehicle speed, and the like. And a speed sensor 92 for detecting the speed of the power transmission system on the output side of.

Further, an external load detecting means 93 for detecting a state in which an external load such as an electric load or an air conditioner drive load is acting on the engine 1 is provided, and the output signals of the load sensor 91 and the speed sensor 92 are input. , The operation of the lockup clutch 6 is controlled based on a first lockup characteristic relating to a predetermined engine load and the speed of the power transmission system on the output side of the torque converter 7, while the external load detection means 93 When a signal indicating the operating state of the external load of the engine 1 is input, the operating region of the lockup clutch 6 is detected by the speed sensor 92 as compared with the first lockup characteristic, and the power transmission system on the torque converter output side is detected. The lock-up clutch 6 based on the second lock-up characteristic that is restricted in the direction of reducing to the high speed side with respect to the speed of The lock-up control means 94 for controlling the operation of is provided.

(Operation) With the above configuration, according to the present invention, the torque converter 7 is operated when no external load is applied to the engine 1.
The lockup clutch 6 is controlled based on a first lockup characteristic relating to the engine load and the speed of the power transmission system on the output side of the torque converter 7. But,
When an external load is applied to the engine 1, the lockup characteristic of the lockup control means 94 is changed from the first characteristic to the second characteristic by the output signal of the external load detection means 93 which detects the external load. The lock-up clutch 6 is operated based on the second lock-up characteristic.

At this time, the second lock-up characteristic is restricted in the direction in which the operating region of the lock-up clutch 6 is reduced to the high speed side with respect to the speed of the power transmission system on the output side of the torque converter as compared with the first lock-up characteristic. With this characteristic, it is possible to prevent the transmission 3 from entering a lockup state when an external load is applied to the engine 1. Therefore, the effect of increasing the torque due to the slip of the torque converter 7 can be utilized to reduce the engine driving force for vehicle running. Can be supplemented.

(First Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows the overall configuration of a control device for an automatic transmission according to a first embodiment of the present invention, in which 1 is a vehicle-mounted engine having an output shaft 2 and 3 is a drive wheel of a vehicle for changing the rotation of the engine 1. (Not shown) is an electronically controlled automatic transmission. The transmission 3 is, as shown in enlarged detail in the upper part of FIG.
Transmission gear mechanism 4 as a transmission element, and the transmission gear mechanism 4
And a torque converter 7 provided with a lock-up clutch 6 which is arranged between the input shaft 5 and the output shaft 2 of the engine 1 and directly connects the shafts 2 and 5.

The torque converter 7 includes a pump 8 coupled to the output shaft 2 of the engine 1, a turbine 9 arranged to face the pump 8, and a stator 10 arranged between the pump 8 and the turbine 9. Therefore, the input shaft 5 of the speed change gear mechanism 4 is coupled to the turbine 9. Further, the lock-up clutch 6 is provided between the input shaft 5 of the speed change gear mechanism 4 and the pump 8, and the lock-up clutch 6 is operated by the pressure of hydraulic oil circulating in the torque converter 7. While directly connecting the output shaft 2 of the engine 1 and the input shaft 5 of the speed change gear mechanism 4 to each other, a hydraulic control circuit described later.
The releasing hydraulic pressure supplied by 40 holds the non-operating state to release the direct connection between the two shafts 2, 5.

The speed change gear mechanism 4 is composed of a multi-stage gear mechanism 11 connected to the input shaft 5 thereof and an overdrive planetary gear mechanism 28 installed between the multi-stage gear mechanism 11 and the torque converter 7. ing. The multi-stage gear mechanism 11 has a front planetary gear mechanism 12 and a rear planetary gear mechanism 13, and the sun gear 14 of the front planetary gear mechanism 12 and the sun gear 15 of the rear planetary gear mechanism 13 are connected by a connecting shaft 16. The input shaft 17 of the multistage gear mechanism 11 is connected to the connecting shaft 16 via the front clutch 18.
In addition, the rear clutch 19 is connected to the internal gear 20 of the front planetary gear mechanism 12. A front brake 21 is provided between the connecting shaft 16, that is, the sun gears 14, 15 and the transmission case 3a. The planetary carrier 22 of the front planetary gear mechanism 12 and the internal gear 23 of the rear planetary gear mechanism 13 are connected to the output shaft 24. A brake 26 and a one-way clutch 27 are provided. The multi-stage gear speed change mechanism 11 has three forward gears and one reverse gear in a conventionally known form.
It has a gear shift stage, clutches 18 and 19 and brakes 21 and 26.
The desired shift speed is obtained by appropriately operating.

Further, in the planetary gear mechanism 28 for overdrive, a planetary carrier 30 that rotatably supports the planetary gear 29 is connected to the input shaft 5 of the speed change gear mechanism 4.
Sun gear 31 is an internal gear via a direct coupling clutch 32.
It is designed to be combined with 33. An overdrive brake 34 is provided between the sun gear 31 and the transmission case 3a.
Further, the internal gear 33 is connected to the input shaft 17 of the multistage gear mechanism 11. Then, when the direct coupling clutch 32 is engaged and the brake 34 is released, the overdrive planetary gear mechanism 28 couples the shafts 5 and 17 in a direct coupling state, the brake 34 is engaged and the clutch 32 is released. The shafts 5 and 17 are over-driving when they are connected.

A hydraulic control circuit 40 for hydraulically controlling the operation of actuators of various friction elements and the lockup clutch 6 in the speed change gear mechanism 4 of the transmission 3 is shown in the lower part of FIG. The hydraulic control circuit 40 has an oil pump 41 driven by the engine 1. The hydraulic oil discharged from the oil pump 41 to the pressure line 62 is adjusted by the pressure adjusting valve 46 to the select valve 42. It is designed to guide you. The select valve 42 is 1, 2, D,
The pressure line 62 communicates with the ports 42a to 42c of the select valve 42 when the shift range positions are N, R, and P, and the shift range positions are the 1, 2 and P positions. Select valve above
The port 42a of 42 is connected to an actuator 56 for actuating the rear clutch 19, and the rear clutch 19 is held in the engaged state when the select valve 42 is in the position described above. The port 42a of the select valve 42 is also connected to the vicinity of the left end of the 1-2 shift valve 43 in the figure, and the spool 43a thereof is pressed to the right in the figure. Further, the port 42a is connected to the right end of the 1-2 shift valve 43 in the figure through the first line 63 and the 2-3 shift valve 44 through the second line 64.
3-4 shift valve through the third line 65 at the right end in the figure
In Figure 45, they are connected to the upper end respectively. The first,
First, second and third drain lines 67 to 69 are branched and connected to the second and third lines 63 to 65, and these drain lines 67 to 69 are respectively connected to the drain lines 67 to 69. The first, second and third solenoid valves 52 to 54 for opening and closing are connected to each other, and when the solenoid valves 52 to 54 are excited by power supply, the pressure line 62 and the port 42a of the select valve 42 communicate with each other. By closing the drain lines 67 to 69 in the state of being kept, the pressure in the first to third lines 63 to 65 is increased.

Further, the port 42b of the select valve 42 is connected to the second lock valve 47 via a line 79, and the pressure from this port 42b acts to push down the spool 47a of the second lock valve 47 in the figure. When the spool 47a of the second lock valve 47 is at the lower position, the line 7
The line 9 communicates with the line 80, and the hydraulic pressure is introduced into the engagement side pressure chamber 57a of the actuator 57 of the front brake 21 to hold the front brake 21 in the operating direction.

Further, the port 42c of the select valve 42 is connected to the second lock valve 47, and the pressure from the port 42c acts to push the spool 47a of the second lock valve 47 upward in the drawing. Also, the port 42c is connected to the pressure line 72
It is connected to the 2-3 shift valve 44 via. The pressure line 72 is a line when the spool 44a of the 2-3 shift valve 44 moves to the left in the figure due to the pressure in the second line 64 increased by the excitation of the solenoid valve 53 of the second drain line 68. Connect to 73. The line 73 is connected to the release side pressure chamber 57b of the actuator 57 of the front brake 21, and when the hydraulic pressure is introduced into the pressure chamber 57b, the actuator 57 resists the pressure of the engagement side pressure chamber 57a. Then, the brake 21 is operated in the releasing direction. The pressure in the line 73 is the same as that in the actuator 15 of the front clutch 18.
Is also guided to engage the clutch 18.

In addition, the select valve 42 also has a port 42d communicating with the pressure line 62 at its 1-shift range position, the port 42d reaching the 1-2 shift valve 43 via a line 74, and further passing through the line 75 to the rear side. It is connected to the actuator 59 of the brake 26. The 1-2 shift valve 43 and the 2-3 shift valve 44 described above. When the solenoid valves 52 and 53 are excited by a predetermined signal, the spools 43a and 44a respectively
To switch the line, which activates the specified brake or clutch to activate 1-2 speed and 2-3 speed respectively.
It is configured to perform a high speed shift operation. Also,
Reference numeral 48 is a cutback valve for stabilizing the hydraulic pressure from the pressure regulating valve 46, and 49 is a pressure regulating valve according to the magnitude of the intake negative pressure of the engine 1.
Vacuum slot valve that changes the line pressure from 46,
Reference numeral 50 is a throttle backup valve which assists the vacuum throttle valve 49.

Further, the hydraulic control circuit 40 is provided with an actuator 60 controlled by the 3-4 shift valve 45 in order to control the operation of the clutch 32 and the brake 34 of the planetary gear mechanism 28 for overdrive. The engagement side pressure chamber 60a of the actuator 60 is connected to the pressure line 62, and the pressure of the line 62 pushes the brake 34 in the engagement direction. Further, the 3-4 shift valve 45 has the above-mentioned 1-2 and 2
Like the -3 shift valves 43 and 44, when the solenoid valve 54 is excited, the spool 45a thereof moves downward in the figure. As the spool 45a moves, pressure line 62 and line 76
Communication with line 71 is cut off and line 76 is drained, which causes the actuator of brake 34 to
The hydraulic pressure acting on the release side pressure chamber 60b of 60 disappears, the brake 34 is operated in the engaging direction, and the actuator 61 of the clutch 32 acts to release the clutch 32.

Further, the hydraulic control circuit 40 includes a lockup control valve 51.
Is provided. The lockup control valve 51 is connected to the port 42a of the select valve 42 via the fourth line 66. Similar to the drain lines 67 to 69, a fourth drain line 70 having a fourth solenoid valve 55 as an electromagnetic means is branched and connected to the line 66. And
The lock-up control valve 51 shuts off the communication between the line 77 and the line 78 by the spool 51a when the drain line 70 is closed and the pressure in the line 66 is increased due to the excitation of electric power from the solenoid valve 55. When the lockup clutch 6 is drained, the lockup clutch 6 is moved in the connecting direction.

Tables 1 to 3 below show the operational relationship between each shift speed and lockup and each solenoid valve, and the operational relationship between each shift speed, clutch, and brake in the above configuration.

Further, in FIG. 2, 90 is an electronic control circuit incorporating a computer for controlling ON / OFF operations of the solenoid valves 52 to 55 in the hydraulic control circuit 40. The electronic control circuit 90 includes a throttle opening sensor 91 that detects the load of the engine 1 based on the opening of the throttle valve 1b that opens and closes the intake passage 1a of the engine 1 (throttle opening), and the output of the torque converter 7. Turbine rotation speed sensor 92 as a speed sensor for detecting the rotation speed T of the turbine 9 constituting the power transmission system on the side, and an external load other than the traveling load applied to the engine 1 (for example, a compressor driving load or an electric load of the air conditioner). ) Is operating, an output signal from an idle-up detecting means 93 as an external load detecting means for detecting the engine rotational speed by an idle-up state in which the engine rotational speed is slightly raised from the normal idle rotational speed is inputted. .
The electronic control circuit 90, as shown in FIG.
Shift-up shift line set in advance based on the characteristics of throttle opening (engine load) with respect to turbine speed
It stores a shift characteristic map having Lu and a shift-down shift line Ld and a lock-up characteristic map having similarly set lock-up operation control line Ll _N and lock-up release control line Ll _F , Position sensor
The shift lines Lu and Ld and the lock-up control line of the characteristic map in which the actual throttle opening (engine load) and turbine speed T detected by 91 and the turbine speed sensor 92 are stored in the electronic control circuit 90. Ll
_N and L _F are compared and compared to calculate whether or not gear shifting should be performed and whether or not lockup should be performed, and the ON / OFF signal of gear shifting and the ON / OFF signal of lockup are respectively calculated by the hydraulic control circuit 40. Output to each solenoid valve 52-55. Also,
When an idle-up signal (signal of an external load acting state) is input from the idle-up detecting means 93 to the electronic control circuit 90, as shown by a broken line in FIG. 4, a map of lock-up characteristics stored in advance is displayed. Each value of the lockup operation control line Ll _N and the lockup release control line Ll _NF is substantially shifted to the high speed side of the turbine speed by the constant T ₀ to limit the lockup operation region to the direction of reducing the high speed side. Is configured.

Here, the control procedure for the automatic transmission 3 by the electronic control circuit 90 will be further described in detail. The main routine of the program installed in the computer of the electronic control circuit 90 is performed according to the flowchart shown in FIG. That is, in the shift control, the initial rise setting is performed in step S ₁ after the start. In this initial rise setting, first, the ports of various control valves in the hydraulic control circuit 40 of the automatic transmission 3 and necessary counters are initialized to put the transmission gear mechanism 4 in the first speed state and the lockup clutch 6 in the released state. Each is set. Thereafter, in step S ₂ , it is determined whether the position of the select valve 42, that is, the shift range is the N or P range,
The same step S ₂ is continued while this determination is YES.
If the decision is NO, and in turn the shift range is determined whether the 1 range in step S _3, the process shifts to a step S ₄ when this determination is YES, the fourth solenoid valve of the hydraulic control circuit 40 55 The ON signal to output unlocks the lockup by output, and then in step S ₅ , it is calculated whether the engine overruns when the gear position of the transmission gear mechanism 4 is downshifted to the first speed. Step when Thereafter, a determination is made whether or not to overrun on the basis of the operation in step S _6, the speed change gear mechanism 4 at step S ₇ when this determination is YES in the second speed, a NO
It emits a signal for controlling the shift valve so as to shift to the first speed at S ₈ to the solenoid valves 52 to 54 of the hydraulic control circuit 40. Thereafter, the flow returns to the initial step S _2.

On the other hand, when the determination in step S ₃ is NO, it is determined in step S ₉ whether or not the shift range is 2 ranges, and when the determination is YES, the process proceeds to step S ₁₀ to lock up. And the speed change gear mechanism 4 is changed to the second speed in step S ₁₁ . When the determination in step S ₉ is NO, that is, when the shift range is the D range, the step
In S ₁₂ , S ₂₄ , and S ₃₆ , shift-up control including shift-up determination, shift-down control including shift-down determination, and lock-up control including lock-up determination are sequentially performed.

The upshift control is performed based on the upshift control subroutine shown in FIG. That is, first, reads the gear position of the transmission gear mechanism 4 in step S _13, the read gear position is a judgment of whether or not fourth gear, when this determination is YES, no further Since the shift up of No. cannot be performed, the control ends as it is. On the other hand, when the determination in step S ₁₃ is NO, the throttle opening is read in step S ₁₄ , and the read throttle opening is read in next step S ₁₅ in the shift-up shift line in the shift-up map shown in FIG. 7. The set turbine rotational speed Tmap on the map corresponding to the throttle opening is read by checking against Lu. Next, in step S ₁₆ , the actual turbine speed T is read out, and then in step S ₁₇ , the actual turbine speed T is set to the set turbine speed Tm.
It is judged whether it is larger than ap, and this judgment is T> Tmap
Shift up flag F ₁ in step S ₁₈ when it is YES
Determines whether F ₁ = 0. This flag F ₁ is set to F ₁ = 1 when the shift up is executed and the history of the shift up state is stored.
Then, when the decision in step S ₁₈ is NO, it terminates the control the shift-up is performed. If the determination is YES, the flag F ₁ is set to F ₁ = 1 in step S ₁₉ , and then the gear position of the transmission gear mechanism 40 is shifted up by one step in step S ₂₀ to end the control.

On the other hand, when the decision in step S ₁₇ is NO in T ≦ Tmap is multiplied by a coefficient 0.8 to the set turbine speed Tmap modify the settings turbine speed Tmap in step S _21, in FIG. 7 the broken lines A new shift-up transmission line Lu 'having a hysteresis as shown by is formed. Then
In step S _22, similarly to the step S _17, a determination is made whether the actual or turbine speed T is larger than the modified set turbine speed Tmap, this determination is YES
If NO, the shift up flag F ₁ is reset to F ₁ = 0 in step S ₂₃ , and if NO, the control ends. This completes the subroutine for upshift control.

Shift-down control including shift-down determination performed after execution of such shift-up control is performed based on the shift-down control subroutine shown in FIG. In this shift-down control, as in the case of the shift-up control, first, it reads the gear position of the transmission gear mechanism 4 in step S _25, it is determined whether the gear position is first gear. If this determination is YES, the shift down cannot be performed further, so the control is ended as it is.
On the other hand, when the decision in step S ₂₅ is NO reads the throttle opening in step S _26, the next step S
_{At 27} , the read throttle opening is compared with the shift down shift line Ld of the shift down map shown in FIG. 9 to set the turbine speed Tm on the map according to the throttle opening.
read ap. Next, in step S ₂₈ , the actual turbine rotation speed T is read out, and in subsequent step S ₂₉ , it is determined whether or not the actual turbine rotation speed T is smaller than the set turbine rotation speed Tmap. This judgment is YE with T <Tmap
When a S, in step S _30, the shift down flag F ₂ is set to "1" when the shift down is executed is determined whether the F ₂ = 0, the determination is NO At this time, since the downshift is being performed, the control is ended as it is. On the other hand, if the determination in step S ₃₀ is Y
If ES, shift down flag F ₂ in step S _31.
Is set to F ₂ = 1 and then the gear position of the transmission gear mechanism 4 is shifted down by one step in step S ₃₂ , and thereafter the control is ended.

On the other hand, when the determination in step S ₂₉ is NO of T ≧ Tmap, the set turbine speed T is set in step S ₃₃ .
The map is divided by a coefficient of 0.8 and corrected to form a new downshift line Ld 'having hysteresis as shown by the broken line in FIG. Then, in step S _34,
The actual turbine speed T is a judgment of whether or not smaller than the set turbine speed Tmap which is the modified, as it is when this determination is YES, the shift down flag F ₂ in step S ₃₅ when the answer is NO The control is ended after resetting F ₂ = 0. This completes the subroutine for downshift control.

Furthermore, after executing such downshift control, the lockup control including the lockup determination as described above is performed.
This is performed based on the lockup control subroutine shown in the figure. In the lockup control, first, the first step S
_The throttle opening is read at ₃₇ , and the next step S
_The throttle opening read in ₃₈ is the lockup release control line Ll _{F of the} lockup release map shown in the broken line in FIG. 11.
And the set turbine speed Tmap on the map corresponding to the throttle opening is read. Then, in step S ₃₉ , it is determined whether or not the engine 1 is in the idle-up state based on the output signal of the idle-up detection means 93. If the determination is YES, the set turbine speed Tmap read in step S ₄₀ is set. After correcting the set turbine speed Tmap to the high speed side of the turbine speed by adding the constant T _0, and when the determination is NO, the process directly proceeds to step S ₄₁ . In this step S ₄₁ , the actual turbine rotation speed T is read out, and in the next step S ₄₂ , the turbine rotation speed T is read.
Is smaller than the set turbine speed Tmap. Proceeds to step S ₄₃ when this determination is YES, the after releasing the lock-up and the lock-up clutch 6 in a non-operating state, the control is ended. On the other hand, when the decision in step S ₄₂ is NO, the process shifts to a step S _44, the throttle opening read in step S ₃₇ first
1 Read the set turbine speed Tmap on the map according to the throttle opening by checking against the lock-up operation control line Ll _N of the lock-up operation map shown by the solid line in FIG. 1, and then, as in steps S ₃₉ and S ₄₀ above. In step _S45 , it is determined whether the engine 1 is in the idle-up state based on the output signal of the idle-up detection means 93, and this determination is YES.
In step S ₄₆ , the constant T ₀ is added to the set turbine speed Tmap read in step S ₄₄ to correct the set turbine speed Tmap to the high speed side of the turbine speed, and when the determination is NO, the condition remains unchanged. Move to step S ₄₇ . This step S ₄₇ in the above actual turbine rotational speed T is determined whether greater than the set turbine speed Tmap, step S when this determination is YES
_The lockup clutch 6 is activated at ₄₈ and the transmission 3
After locking up, when the determination is NO, the control is ended as it is. Thus, the lockup control is completed.

Therefore, in this embodiment, the entire steps S ₃₇ to S ₄₈ to dwell in the step S _36, that the lock-up control subroutine, inputs the output signals of the throttle opening sensor 91 and turbine speed sensor 92, is Me out previously The operation of the lock-up clutch 6 is controlled based on the first lock-up characteristic relating to the throttle opening (engine load) and the turbine speed, while the idle-up detection means 93 controls the idle-up state of the engine 1 (that is, the external load When a signal indicating the (action state) is input, the second lockup in which the operating region of the lockup clutch 6 is limited in the direction of reducing the turbine speed to the high speed side as compared with the first lockup characteristic described above. The lock-up control means 94 is configured to control the operation of the lock-up clutch 6 based on the characteristics. That.

Further, step S _12, S _24, i.e. the shift-up control routine and a shift-down control routine, receives the output signals of the throttle opening sensor 91 and turbine speed sensor 92, throttle opening and turbine speed that have been set in advance The shift control means 95 is configured to control the actuation / non-actuation of each actuator of the transmission gear mechanism 4 based on the characteristics of shift up and shift down regarding the above.

Therefore, in the above embodiment, when the external load is not acting on the engine 1, the operation of the lockup clutch 6 is controlled based on the normal first lockup characteristic relating to the throttle opening and the turbine speed. It On the other hand, when an external load is acting on the engine 1 due to the compressor load or electric load of the air conditioner, the idle-up detecting means 93 detects the state and receives the output signal of the idle-up detecting means 93. The lockup control means 94 limits the operating region (lockup operating region) of the lockup clutch in the map of the first lockup characteristic to a direction in which the turbine rotational speed is reduced to the high speed side, and the first lockup is performed. The characteristic map is modified to the second lockup characteristic map, and the operation of the lockup clutch 6 is controlled based on the modified second lockup characteristic map. Therefore, when the external load of the engine 1 is applied, the area where the lock-up of the automatic transmission 3 is released is expanded, and it becomes difficult to lock-up.
Therefore, it is possible to compensate for the reduction in the driving force of the engine 1 that occurs when the external load is applied.

In the above embodiment, when the engine 1 receives an external load, the lockup operating region of the lockup characteristic is reduced to the high speed side of the turbine speed, but the lockup clutch 6 is locked in the inoperative state. It may be restricted to hold and release the lockup.

(Second Embodiment) FIGS. 12 and 13 show a second embodiment of the present invention, in which a plurality of lock-up patterns preset according to the running mode of the vehicle are set except for the set mode when the engine idles up. The mode is changed to.

That is, in this embodiment, an electric control system for controlling ON / OFF of the fourth solenoid valve 55 of the hydraulic control circuit 40 in the first embodiment to control the operation and release of the lockup is shown in FIG. Is configured. In the figure, 100 is a throttle opening detection circuit as a load sensor that detects the load of the engine 1 by its throttle opening, and 101 is a torque as a speed sensor that detects the output shaft speed of the torque converter 7, that is, the turbine speed. A converter output shaft speed detection circuit, 102 is an idle-up detection circuit that detects an external load application state depending on an idle-up state of the engine 1, and 103 is a mode switch that detects an output signal of a mode switch for selecting a running mode of the vehicle. In the detection circuit, the traveling modes of the vehicle include a power mode A for increasing the driving force of the vehicle, a normal mode B, and an economy mode C for reducing fuel consumption. Further, 104 is the idle-up detection circuit 102.
And a mode determination circuit 104 that receives each output signal from the mode switch detection circuit 103 and determines the lockup control mode in the transmission 3.
As shown in FIG. 13, there are three types of ac, which are set so that the lockup operation control line Ll _N and the release control line Ll _F relating to the torque converter output shaft speed and the throttle opening are different from each other. The lockup characteristic mode is determined as shown in Table 4 below according to the combination of the idle-up ON / OFF state of the engine 1 and the traveling mode.

Further, 105 is a lockup determination circuit that determines the lockup by receiving the output signals of the throttle opening detection circuit 100, the torque converter output shaft speed detection circuit 101, and the mode determination circuit 104. circuit
Reference numeral 105 determines whether or not lockup should be performed by collating the throttle opening and the torque converter output shaft rotational speed detected by the detection circuits 100 and 101 with the lockup characteristics determined by the mode determination circuit 104. Also, 10
Reference numeral 6 denotes a lockup solenoid drive circuit which receives the output signal of the lockup determination circuit 105 and operates the fourth solenoid valve 55 of the hydraulic control circuit 40 at the time of lockup. Therefore, the mode determination circuit 104 and the lockup determination circuit 1
05 and lock-up solenoid drive circuit 106
When the engine 1 idles up, the lockup operating region is controlled to control the lockup operating state based on the lockup characteristics that the lockup operating region is reduced to the higher speed side of the torque converter output shaft speed than when the engine is not idled up. Means 94 'are constructed.

Therefore, in this embodiment, when the engine 1 is idle-up (that is, when an external load is applied), the lockup characteristic in the economy mode C is substantially higher than the lockup characteristic of the mode C in the lockup operating region. Since the lockup characteristic is changed to the reduced normal mode B, the lockup operation is less likely to be performed, so that the reduction in the driving force of the vehicle due to the external load acting state of the engine 1 can be compensated.

(Effect of the Invention) As described above, according to the present invention, when the external load of the engine is applied, the operating region of the lock-up characteristic in the automatic transmission is set to the high speed side with respect to the speed of the power transmission system on the output side of the torque converter. By limiting the direction of reduction, it is possible to avoid the lock-up state when an external load is applied and to utilize the torque increase effect due to the slip of the torque converter, thus compensating for the reduction of the driving force to the vehicle due to the external load application state of the engine. You can

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. 2 to
FIG. 11 shows the first embodiment of the present invention, FIG. 2 is an overall schematic configuration diagram of a control device for an automatic transmission, and FIG. 3 is an explanation showing a structure of a mechanical portion of the automatic transmission and a hydraulic control circuit. Figure,
4 is an explanatory view showing characteristic maps for shift control and lock-up control, FIG. 5 is a flow chart showing a main routine of shift control, and FIG. 6 is a flow chart showing a shift-up control subroutine of shift control. FIG. 7 is an explanatory view of a shift-up map, FIG. 8 is a flowchart showing a shift-down control subroutine, FIG. 9 is an explanatory view of a shift-down map, and FIG. 10 is a flowchart showing a lock-up control subroutine. The figure is an illustration of a lockup map. 12 and 13 show a second embodiment of the present invention, FIG. 12 is a block diagram showing the overall configuration, and FIG. 13 is an explanatory diagram showing a mode of lockup characteristics. 1 ... Engine, 2 ... Output shaft, 3 ... Automatic transmission, 4
...... Speed change gear mechanism, 5 …… Input shaft, 6 …… Lockup clutch, 7 …… Torque converter, 40 …… Hydraulic control circuit, 90 …… Electronic control circuit, 91 …… Throttle opening sensor, 92 …… Turbine speed sensor, 93 ... Idle-up detection means (external load detection means), 94,94 '... Lock-up control means, 100 ... Throttle opening detection circuit, 101
...... Torque converter output shaft speed detection circuit, 102 ……
Idle-up detection circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Shimaoka 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-59-197669 (JP, A)

Claims (1)

[Claims] 1. A torque converter provided between an output shaft of an engine and an input shaft of a speed change gear mechanism, the torque converter having a lockup clutch connecting the two, a load sensor for detecting an engine load, and the torque converter of the torque converter. A speed sensor for detecting the speed of the power transmission system on the output side, an external load detecting means for detecting a state in which an external load such as an electric load, an air conditioner drive load, or the like is acting on the engine, the load sensor and the speed Input the output signal of the sensor,
The operation of the lockup clutch is controlled on the basis of a first lockup characteristic relating to a predetermined engine load and the speed of the power transmission system on the output side of the torque converter, while the operation state of the external load is controlled by the external load detecting means. When the signal shown is input, the operating region of the lockup clutch is reduced to the higher speed side with respect to the speed of the power transmission system on the output side of the torque converter detected by the speed sensor as compared with the first lockup characteristic. A control device for an automatic transmission, comprising: lockup control means for controlling an operation of a lockup clutch based on a second lockup characteristic restricted in a direction.