JPS60113861A - Lock-up controlling unit for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce fuel consumption by releasing lock-up when an engine is vibrated by knocking or the like. CONSTITUTION:A roghness sensor (j) for detecting the roughness condition such as knocking condition is provided in an engine (b), and the output of said sencor (j) is sent to the input of a roughness condition judging means (k). And the output of said means (k) is sent to the input of a controller (i) and lock-up is released when the engine (b) is vibrated by knocking or the like. Thus, the operative region of lock-up can be expanded to reduce fuel consumption without producing any troubles due to knocking or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to automatic transmissions used in automobiles, and more particularly to a lockup control device for an automatic transmission equipped with a lockup function.

(Prior art) Automatic transmission in which a torque converter and a multi-speed gear mechanism are combined, and the transmission path of the transmission gear mechanism is switched by selective operation of a plurality of fluid actuators to obtain a plurality of gears. However, due to the slippage of the torque converter, the power transmission efficiency of automatic transmissions is inferior to that of mechanical clutches, and as a result, automobiles equipped with automatic transmissions have a disadvantage in terms of fuel efficiency. Therefore, unless the input side and output side of the torque converter are slid to avoid a shift shock, such as when changing gears, or when the torque increasing action of the torque converter is required, the input side of the torque converter and the output side of the torque Automatic transmissions have been provided that have a so-called lock-up function that is mechanically directly connected to the output side to improve fuel efficiency.

In this type of automatic transmission, as shown in Figure 1,
For example, lock-up is activated and released according to a predetermined operating range based on the throttle opening and torque converter turbine rotation speed, but in order to improve fuel efficiency as much as possible, the lock-up release line must be set low. It is necessary to set it on the rotation speed side to widen the lock-up operating range. However, if this is done, knocking will occur when the engine speed decreases while the torque converter remains locked up, resulting in poor riding comfort and engine stalling. Therefore, conventionally, the lock-up release line is set to a relatively high rotation speed side, and when the turbine rotation speed (or engine rotation speed) falls below the set rotation speed, the lock-up is released with a margin. This is intended to prevent knocking, but in this case, lockup is often released even though knocking does not actually occur, which unnecessarily narrows the lockup operating range and sacrifices fuel efficiency. It was supposed to be.

By the way, regarding the control of lock-up activation and release, for example, Japanese Patent Laid-Open No. 56-127856 and Japanese Patent Laid-open No. 57
There is an invention disclosed in Publication No.-6151 and the like. However, these systems prevent the engine from revving up due to torque converter slippage by controlling the lock-up release to be delayed for a certain period of time during upshifts, and extend the lock-up operating range to a low engine speed range. The purpose of this invention is different from that of the present invention, which aims to improve fuel efficiency.

(Object of the Invention) The present invention was made in view of the above-mentioned actual situation regarding automatic transmissions, and is designed to release lock-up when the engine is in a rough state, that is, in a state where it vibrates due to knocking, etc. . This makes it possible to set the preset lock-up release line to the extremely low rotation speed side, and to shift the lock-up operating range to the low turbine rotation speed or engine rotation speed range without causing any adverse effects such as knocking. The objective is to improve the fuel efficiency of this type of automatic transmission.

(Structure of the Invention) A lock-up control device for an automatic transmission according to the present invention is configured as follows in order to achieve the above object.

That is, as shown in FIG.
A shift change determination system in which signals are input from a sensor that detects the driving state of the vehicle, represented by an engine load sensor C that detects the magnitude of the load on the engine, and a sensor d that detects the output shaft rotation speed of the torque converter, etc. means e, lockup determination means f, and shift change electromagnetic means h1. for switching the fluid control circuit g in response to a shift up signal or a shift down signal from the shift change determination means e and a lockup signal from the lockup determination means. h
2. h3 and a controller 1 for driving and controlling the lock-up electromagnetic means h4, whereby the transmission gear mechanism and the lock-up means of the automatic transmission a are switched and controlled according to the engine load, torque converter output shaft rotation speed, etc. It looks like this. In addition, a roughness sensor j detects a roughness state such as a knocking state of engine b.
and a roughness state determining means k which receives a signal from the sensor j and generates a roughness signal when roughness is detected. When the controller i receives the roughness signal from the roughness state determining means k, the controller i drives and controls the lock-up electromagnetic means h4 to release the lock-up regardless of the signal from the lock-up determining means r. It is composed of

According to such a configuration, even if the lock-up release line set in the lock-up determination means f is set to an extremely low range of the engine rotation speed (or the output shaft rotation speed of the torque converter), the engine roughness state or The associated adverse effects are thus prevented, and it is therefore possible to expand the lock-up operating range and further improve fuel efficiency.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 does not show the mechanical structure and fluid control circuit of the automatic transmission 1. This automatic transmission 1! t1 is composed of a torque converter 10, a multi-stage gear mechanism 20, and an overdrive gear mechanism 40 disposed between the two.

The torque converter 10 includes a pump 13 directly connected to the output shaft 3 of the engine 2 via a drive plate 11 and a case 12, a turbine 14 disposed in the case 12 to face the pump 13, and the pump 13. The stator 15 is disposed between the turbine 14 and the turbine 14, and an output shaft 16 is coupled to the turbine 14. Further, a lock-up clutch 17 is provided between the output shaft 16 and the case 12. This lock-up clutch 17 is constantly pressed in the engagement direction by the pressure of the working fluid circulating within the torque converter 10, and is released when release fluid pressure is supplied from the outside.

The multi-speed gear mechanism 20 has a front planetary gear mechanism 21 and a rear planetary gear mechanism 22, and sun gears 23, 24 of both mechanisms 21, 22 are connected by a connecting shaft 25. The input shaft 26 to this multi-speed gear mechanism 20 is
It is configured to be connected to the connecting shaft 25 via the front clutch 27 and to the ring gear 29 of the front planetary gear mechanism 21 via the rear clutch 28, and the connecting shaft 25, that is, one double-way M gear A second brake 31 is provided between the sun gear 23.24 and the transmission case 30 at 21.22. The binion carrier 32 of the front planetary gear mechanism m21 and the ring gear 33 of the rear planetary gear mechanism 22 are connected to the output shaft 34, and between the binion carrier 35 of the rear planetary gear mechanism 22 and the transmission case 30. has a low reverse brake 36
A one-way clutch 37 and a one-way clutch 37 are respectively provided.

On the other hand, in the overdrive transmission gear mechanism 40, a binion carrier 41 is connected to the output shaft 16 of the torque converter 10, and a sun gear 42 and a ring gear 43 are connected to the output shaft 16 of the torque converter 10.
and are connected by a direct coupling clutch 44. Further, an overdrive brake 45 is provided between the sun gear 42 and the transmission case 30, and the ring gear 43 is connected to the input shaft 26 to the multi-speed gear mechanism 20.

The multi-stage transmission mechanism 20 configured as described above is conventionally known,
For selective operation of the clutches 27, 28 and brakes 31, 36, three forward stages are provided between the input shaft 26 and the output shaft 34;
A gear ratio of one reverse gear is obtained. Further, the overdrive speed change gear mechanism 40 directly connects the output shaft 16 of the torque converter 10 and the input shaft 26 to the multi-stage speed change gear mechanism 20 when the clutch 44 is engaged and the brake 45 is released. is released and brake 45 is engaged, coupling said shaft 16.26 into overdrive.

Next, the fluid control circuit of the automatic transmission will be explained.

Working fluid discharged into the main line 51 from the oil pump 50, which is constantly driven by the engine output shaft 3 via the torque converter 10, is guided to the select valve 53 after its oil pressure is adjusted by the pressure regulating valve 52. This select valve 53 is P.

R, N, D, has a range of 2.1, 0.2. The main line 51 is connected to the boat a at the lunge.

This boat a is connected to the rear clutch 2 via a line 54.
Therefore, in each of the forward ranges 2' and 1, the rear clutch 28a is connected to the rear clutch 28a.
8 is always kept in a fastened state.

Moreover, the boat a is the first boat. Second. Third. It communicates with fourth control lines 56, 57, 58, and 59.

These control lines 56 to 59 are led to one end of a 1-2 shift valve 61, a 2-3 shift valve 62, a 3-4 shift valve 63, and a lock-up valve 64, respectively. The drain lines are 66 and 67 respectively.
．． 68, 69 are branched and these drain lines 6
6 to 69 respectively open and close. Second. Third. A fourth solenoid 71°72.73.74 is provided. When these solenoids 71-74 are OFF, the drain lines 66-69 are released and the pressure in the corresponding control lines 56-59 is zero, but when they are ON, the drain lines 66-69 are released.
By closing 69 and increasing the pressure in the control lines 56-59, the above 1-2 shift valve 61.2-3 shift valve 6
2.3-4 Move the spools 61a, 62a, 63a, and 64a of the shift valve 63 and lock-up valve 64 from the positions shown in the figure by arrows (a), (b), (c), and (d), respectively.
move in the direction.

The boat a in the select valve 53 also reaches the 1-2 shift valve 61 via a line 76 branched from the line 54, and the spool 61a is moved in the (a) direction by the working fluid from the first control line 56. When moved to line 77, it also connects to second lock valve 7.
8 and line 79 to the engagement side port 318' in the actuator 31a of the second brake 31. As a result, working fluid is supplied to the boat 31a', and the second brake 31 is engaged. here,
The second lock valve 78 is connected to the line 80.8 from both boats b and C of the select valve 53 in the D range.
1, and the lines 77 and 79 are kept in communication as shown.
In range 2, where boat C is closed, working fluid is supplied only from boat b, and spool 78a moves downward, thereby connecting lines 80 and 79. Therefore, in the 2nd range, the second brake 31 is 1-2.
It will be fastened regardless of the state of the shift valve 61.

Also, boat C connected to main line 51 in D range.
is led to the 2-3 shift valve 62 by the line 81 via the one-way throttle valve 82. And said 2-
When the spool 62a of the 3-shift valve 62 is moved in the (B) direction by the working fluid from the second control line 57, it is connected to a line 83, which is further branched into lines 84 and 85, one of which is connected to the second brake 31. The other side connects to the release side port 318'' of the actuator 31a, and the other side connects to the actuator 27a of the front clutch 27.Thereby, the boat 31a Lr and the actuator 27a
The second brake 31 is released and the front clutch 27 is engaged.

In addition, in the lunge, the boat d of the select valve 53 communicates with the main line 51, and the working fluid is guided to the 1-2 shift valve 61 via the line 86, and in this case, the spool 61a of the valve 61 is not shown in the figure. Since it is located at this position, it is further connected to the actuator 36a of the low reverse brake 36 via a line 87. As a result, the low reverse brake 36 is engaged.

Further, in the R range, the boat 0 and the boat d are connected to the main line 51, so that the working fluid is guided to the 2-3 shift valve 62 through the line 88, and in this case, the spool 62a of the valve 62 is The lines 83 and 84 are located at the positions shown in the figure.
Second brake actuator 31a via 85
and the actuator 27a of the front clutch 27. As a result, in the R range, the front clutch 27 is engaged together with the low reverse brake 36. In this case, since the boat a is closed, the rear clutch 28 will be released.

The main line 51 is selectively switched to its course by the select valve 53 as described above, and at the same time, the branch line 89
．． 90 to the 3-4 shift valve 63 and the engagement side boat 458' of the actuator 458 of the overdrive brake 45. The line 89 led to the 3-4 shift valve 63 further leads to lines 91 and 92 when the spool 63a of the valve 63 is in the position shown, and one line 91 connects to the actuator 44a of the direct coupling clutch 44. , the other line 92 reaches the release side boat 45 a JL of the overdrive brake actuator 4.5 a. Therefore, when the 3-4 shift valve 63 is in the illustrated state, both the boats 458' on the engagement side and the release side of the overdrive brake actuator 45a.

45a'', the overdrive brake 45 is released, and the direct coupling clutch 44 is engaged.Then, the spool 63a of the 3-4 shift valve 63 is connected to the spool 63a from the third control line 58. By draining the lines 91..92 when moved in the (c) direction by the working fluid, the direct coupling clutch 44 is released and the overdrive brake 45 is engaged.

Furthermore, working fluid is led from the main line 51 to a lock-up valve 64 via a branch line 93 that passes through the pressure regulating valve 52. When the spool 64a of the valve 64 is in the position shown in the figure, it reaches the inside of the torque converter 10 via the line 94,
The lock-up clutch 17 inside o is disengaged. Then, the spool 64a of the lock-up valve 64 is
By draining the line 94 when moved in the (d) direction by the working fluid from the control line 59,
The lock-up clutch 17 is the torque converter 10
It is fastened by the fluid pressure inside.

In addition to the above configuration, this fluid control circuit includes a cutback valve 95 that stabilizes the oil pressure from the pressure regulating valve 52, and a vacuum throttle that changes the line pressure by the pressure regulating valve 52 according to the magnitude of the intake negative pressure. A valve 96 and a throttle backup valve 97 to assist the throttle valve 96 are provided.

Regarding the above configuration, the relationship between each shift solenoid 71 to 73 and the gear position in the D range, the relationship between the solenoid 74 and lockup, and the clutch in each range,
The relationship between the operating state of the brake and the gear position is shown in the first. Second
．． It is shown in Table 3.

The following is a margin: Table 1 Table 2 Next, the configuration of the electric control system of the automatic transmission will be explained using FIG. 4.

This system is equipped with an electronic control circuit 100 consisting of an input/output device 101, a RAM (Random Access Memory) 102, and a CPU (Central Processing Unit) 103.

The input/output device 101 receives a load signal $1 from an engine load sensor 1Q4 that detects the engine load based on the opening degree of a throttle valve 5 provided in the intake passage 4 of the engine 2, and a turbine rotation speed (torque converter). A speed signal S2 from a sensor 105 that detects the rotational speed of the output shaft is input.

Then, the input/output device 101 receives these signals $1, S
2 is processed and supplied to the RAM 102, and the RAM 10
2 are these signals S1. While storing S2, CP
These signals S1. S2 or other data is supplied to the CPU 103. CPU
103, the signals S1.
By comparing the engine load and turbine rotation speed indicated by S2 with a map indicating the range of shift control and lock-up control as shown in FIG. conduct. Here, the lock-up release line in this map is set at a significantly lower rotation speed than in the conventional one.

Then, in accordance with the calculation result by the CPU 103, the 1-2 shift valve 61 (not shown in FIG. 3) is transferred from the input/output device 101.
A shift control signal S3 is applied to the first to third solenoids 71 to 73 that operate the 2-3 shift valve 62 and 3-4 shift valve 63, and a lock-up control signal S4 is applied to the fourth solenoid 74 that operates the lock-up valve 64. Output.

In addition to the above configuration, this system is also equipped with a knock sensor 106 that detects the knocking state of the engine 2, and an output signal S5 of the sensor 106 is input to the electronic control circuit 100. The control circuit 100 determines whether knocking is occurring in the engine 2 based on the signal S5, and if it is determined that knocking is occurring, causes the input/output device 101 to release the lockup. The lock-up control signal S4 is applied to the fourth solenoid 74.
Output to.

Next, the specific operation of the electronic control circuit 100 will be explained according to the flowcharts shown in FIG. 6 and subsequent figures.

[First, to explain the main control flowchart shown in FIG. 6, the control circuit 100 first performs steps A1 to A.
3, after initializing various states and decrementing the count value of the shift timer set to the predetermined initial value by 1 at the time of shift change, the range set by the shift lever or select valve 53 is read. . If it is set to lunge, execute steps A4 to A5 to A9, cancel the first block up, and use 81 calculation to determine whether or not the engine rotation will overrun when downshifting to 1st gear. After checking, shift to 2nd gear if an overrun occurs, and shift to 1st gear if an overrun does not occur. If the 2nd range is set, steps A4 to A10 to A12 are executed to release the lockup and then shift to the 2nd speed.

On the other hand, if the setting is other than lunge and 2 ranges, that is, D range, the shift-up control, shift-down control, and lock-up control described later are performed in steps A13 to A1s, and after performing these 11J III, step At A+6, a delay time of a certain time (for example, 50771 seconds) is provided, and the next cycle is executed from step A2.

Shift-up control Next, the shift-up control in step A13 in the above main control will be explained. As shown in FIG.
In this control, first, in step B1, it is checked whether the transmission gear mechanism 20.40 shown in FIG. . If the speed is other than 4th, follow steps 82 to B5 to read the current throttle opening, read out the set turbine rotation speed T map corresponding to the read throttle speed from the preset and stored shift-up map, and The actual turbine rotation speed T map is read and compared with the set turbine rotation speed T map.

Here, the shift-up map shows the set turbine rotation speed T ma corresponding to each throttle opening as shown in FIG.
p is stored as a shift-up line MLI, and this shift-up line MLI corresponds to the boundary line X between the shift-up zone and the hold zone shown in FIG. Then, the actual turbine rotation speed T is the set turbine rotation speed T
If the shift-up flag F1 is '0' in a case where the driving region is in the shift-up zone shown in FIG. 5 or FIG. I 11
, and then shift up the gear by one gear. Then, in step B9, the shift timer T is set to an initial value. The shift-up flag F1 indicates that shift-up control has been performed when it is 1. Therefore, if the flag F1 has already been set to "1" in step B6, there is no need to shift up again. The control ends.Also, when it is determined in step B5 that the actual turbine rotation speed T is smaller than the set turbine rotation speed TI'l1ap, 0.8 is added to the set turbine rotation speed Tmap according to steps B+o to B12. By multiplying by
Newly set turbine rotation speed T mal corresponding to I
Only if it is smaller than l, reset the shift up flag F1 to O in preparation for the next cycle, and if the actual turbine rotation speed is greater than the new set turbine rotation speed Tmap, then end the control and shift. Shift to down control. The purpose of this control in step B1o-812 is to form a hysteresis zone and prevent so-called chattering, which is a complicated shift when the turbine rotational speed is on the shift-up line Mu.

In addition, the downshift control in step A14 in Fig. 6 is as follows:
The process is executed as follows according to the flowchart of FIG.

First, in step C1, it is confirmed that the transmission gear mechanism 20.40 is in a gear other than 1st gear, that is, in which downshifting is possible, and then the actual throttle opening is read in accordance with steps 02 to C5, and the 10th From the shift down line Md set in the shift down map as shown in the figure, the set turbine rotation speed T corresponding to the throttle opening at that time
Read the map and compare it with the actual turbine rotation speed. Here, the shift down line Md corresponds to the boundary line Y between the hold zone and the shift down zone shown in FIG. Then, when the actual turbine rotation speed T map is smaller than the set turbine rotation speed T map, that is, when the operating region is in the downshift zone of FIG. 5 or FIG. 10, the downshift flag F2 is set according to steps C6 to C8. After confirming that the flag F2 has been reset to 0'' and setting the flag F2 to 1111+, the gear stage is shifted down by one gear.Then, in step C9, the shift timer T is set to the initial value.In this case as well, , if the flag F2 has already been set to °'1'' in step C6, the control ends. Further, in step C5, the actual turbine rotation speed Tll is changed to the set turbine rotation speed Tll.
When it is larger than 1ap, according to step C1o-012, the turbine rotational speed is multiplied by 0.8 and compared with the set turbine rotational speed Tmap.

This means that the set turbine rotation speed Tmap is 110°8
Multiply this to form a new IC downshift line Md' as shown by the broken line in FIG. 10, and compare the actual turbine rotation speed T with a new set rotation speed T map corresponding to this line Md'. Then, only when T>T map, the downshift flag F2 is reset to "OII" to prepare for the next cycle.

Lock-up control Furthermore, the lock-up control shown in step A15 in the main control of FIG. 6 is executed as follows according to the flowchart shown in FIG.

First, step D1. In D2, this control circuit 10
If the signal from the knocking discrimination circuit set to 0 is read, and if the signal is "0", that is, if it is determined that there is no knocking state, the count value of the lock-up release timer, which will be described later, is read in steps D3 and D4. It is confirmed whether the count value T of the lower 1 and speed change timer is O. If the count value T1 is not O, it means that the predetermined time has not passed since the lock-up was released, and if the count value T1 is not O, it means that the predetermined time has not passed since the shift. If , step D5
to release the lockup respectively.

If the count value T1 and the count value T1 are both O, read the throttle opening according to steps D6 to D9, and
The set turbine rotational speed TIIap corresponding to the throttle opening at that time is read from the lockup release line Moft set in the lockup map as shown in FIG. 12, and this is compared with the actual turbine rotational speed TIIap. When the actual turbine rotational speed Tmap is smaller than the set turbine rotational speed Tmap, that is, when it is in the lockup release zone shown in FIG. 12, step D5 is executed to release the lockup.

The actual turbine rotation speed is the above lock-up release line M.
When the turbine rotation speed is larger than the set turbine rotation speed Tmap corresponding to off, in steps D1o and 11, a hysteresis zone of a predetermined width is provided on the high turbine rotation speed side of the lock-up release line Mof[, as shown by the broken line in FIG. The set turbine rotation speed Tmap corresponding to the set lockup operation line M011 is compared with the actual turbine rotation speed T, and when 7>l-map, the lockup operation is controlled in step D12.

However, in the above map, the lockup release line M
ofr (and lockup operating line MOn) is set to a lower turbine rotational speed than before, and the lockup operating range is expanded accordingly. As a result, the lockup will operate unless the turbine speed becomes extremely low, improving fuel efficiency.

However, as the lock-up release line MOf is set to the low rotational speed side, knocking may occur in the lock-up operating range.

However, in that case, since it is determined that the signal is 1 in step D2, that is, in a knocking state, step D1
3, the count value T1 of the lock-up release timer is
After setting , the lock-up release control in step D5 is executed. As a result, in this lock-up control, lock-up is immediately released as soon as knocking occurs, and fuel efficiency is improved without causing adverse effects due to knocking such as deterioration of riding comfort or engine stalling.

The reason why the lockup release timer is set in step D13 above is to prevent the lockup from immediately operating to eliminate knocking after the lockup is released, which makes the activation and release of the lockup complicated. It is possible to avoid so-called chattering that occurs when

(Effects of the Invention) As described above, according to the present invention, in an automatic transmission equipped with a lock-up function, unless the engine is in a roughness state, that is, in a state where it vibrates due to knocking, etc., the automatic transmission has a lock-up function. In addition, the lockup will be activated, and the lockup will be released immediately when the engine becomes rough. As a result, the lock-up operating range is expanded without causing adverse effects such as knocking, and fuel efficiency is improved.

[Brief explanation of the drawing]

Fig. 1 is a map showing the conventional lock-up control area, Fig. 2 is a block diagram showing the overall configuration of the present invention, and Figs.
The drawings show an embodiment of the present invention. Fig. 3 shows the mechanical structure and fluid control port path of an automatic transmission, Fig. 4 shows the control system, and Fig. 5 shows the control area. Figure shown, No. 6
．． 7, 9.11 is a flowchart diagram showing the operation, No. 8
Figures 10 and 12 are a shift-up map, a shift-down map, and a lock-up map used for control, respectively. DESCRIPTION OF SYMBOLS 1... Automatic transmission, 2... Engine, 3... Engine output shaft, 5... Throttle valve, 10... Torque converter, 20.40... Speed change gear m structure, 27.2
8, 31, 36, 44.45...Fluid type 7 type % electromagnetic means, 100...Controller, shift change judgment means, lockup judgment means, roughness state judgment means (control circuit), 1-04... engine load sensor,
105... Turbine rotation speed sensor, 106... Knock sensor (roughness sensor). Applicant: Toyo Kogyo Co., Ltd. Figure 1 Figure 2 Figure 4 Figure 54? I Fig. 7 Fig. 8 Turbine rotation y Fig. 9 Fig. 10 Turbine rotation J length

Claims (1)

[Claims] (1) A torque converter connected to the output shaft of the engine, a speed change gear 414 connected to the output shaft of the torque converter, a lockup means for connecting and connecting the input shaft and output shaft of the torque converter, and the speed change gear A fluid actuator that switches the power transmission path of the gear mechanism to perform speed change operations, an electromagnetic means that controls the supply of pressure fluid to the lockup means and the fluid actuator, a sensor that detects the running state of the vehicle, and a roughness state of the engine. A roughness sensor that detects the
a shift change determining means that receives an output signal from the sensor, compares the output signal with a shift change setting value, and emits a shift up signal or a shift down signal according to the result; and a shift change determining means that detects the running state of the vehicle. A lock-up determining means receives an output signal from the sensor, compares the output signal with a lock-up set value, and issues a lock-up activation or release signal according to the result; a roughness state determining means for emitting a roughness signal when roughness is detected; and receiving an output signal from the shift change determining means and an output signal from the lock-up determining means to drive and control the electromagnetic means, and receiving the roughness signal from the roughness determining means. 1. A lock-up control device for an automatic transmission, comprising: a controller that drives and controls electromagnetic means to release lock-up when a lock-up is received.