JPH06346961A - Speed change controller of automatic transmission - Google Patents

Abstract

PURPOSE:To enable a tie-up in the case of manual downshift to be reliably avoided. CONSTITUTION:A speed change controller of an automatic transmission A is provided with a frictional engaging device 1 for engine brake and a valve mechanism 2 to be electrically controlled, and for selectively supplying oil pressure to the frictional engaging device 1. And a speed change judging means 3 for judging the speed change into the speed change stage with which the frictional engaging device 1 is engaged and an engagement delaying means 4 for maintaining the frictional engaging device 1 in the releasing state until the fixed period determined on the basis of the traveling state including any one of car speed, throttle opening and speed change stage as a parameter passes after commanding the speed change into the speed change stage when the speed change into the speed change state is judged are provided. Accordingly, the engagement timing of the frictional engaging device for engine brake is accurately controlled, so as to prevent a tie-up in the case of downshifting into the speed change stage for bringing engine brake in its play.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a gear shift of an automatic transmission, and more particularly to a gear shift of an automatic transmission in which a friction engagement device for engine brake is controlled by an electrically controlled valve mechanism. The present invention relates to a control device.

[0002]

2. Description of the Related Art Conventional general automatic transmissions for vehicles are constructed such that a manual operation of a shift lever switches a manual valve to engage a friction engagement device for engine braking. This is because at low speeds in the drive range, the one-way clutch is engaged to set the low speeds in order to eliminate shift shocks, so engine braking can be activated in this state. This is because a friction engagement device such as a multi-disc brake provided in parallel with the one-way clutch is engaged there.

The gear speed at which the engine brake is applied varies depending on the selected range. When the number of gear speeds that can be set or the number of selectable ranges increases, a friction engagement device for applying the engine brake is applied. If the selection is made only by the manual valve, the hydraulic circuit becomes extremely complicated. In order to eliminate such inconvenience, the applicant of the present invention has disclosed a device in which a relay valve is provided for controlling engine braking, and the relay valve is controlled by a solenoid valve, as disclosed in Japanese Patent Application No. 3-344.
It is shown in the drawing attached to the application of No. 121 (not known).

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In the device provided with the above-mentioned relay valve, when the engine brake is applied,
The timing of the supply of hydraulic pressure to the friction engagement device for engine braking is controlled by electrically controlling the solenoid valve, but in the case of downshift, it engages with the friction engagement device to be released. There is a possibility that tie-up may occur in which the frictional engagement device and the power friction engagement device are engaged with each other at a hydraulic pressure of a predetermined value or more. Therefore, in order to avoid such an inconvenience, it is conceivable to delay the engagement of the engine brake frictional engagement device.

However, the optimum control cannot always be performed only by such general control. For example, the engagement of the engine brake frictional engagement device is too late for a predetermined running state. The engine speed drops too much, and the engine brake frictional engagement device engages thereafter to increase the engine speed, which causes a shock to worsen.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a shift control device capable of effectively preventing a shift shock at the time of downshifting to a shift stage in which engine braking is effective. It is intended.

[0007]

In order to achieve the above object, the present invention, as shown in FIG. 1, includes an engine brake friction engagement device 1 and an electrically controlled friction engagement device. 1. A shift control device for an automatic transmission A comprising a valve mechanism 2 for selectively supplying hydraulic pressure to 1, and a shift determination means 3 for determining a shift to a shift stage in which the friction engagement device 1 is engaged, When a shift to the shift stage is determined,
Engagement delay means 4 for maintaining the friction engagement device 1 in the released state until a predetermined time has elapsed after instructing the shift to the shift stage, and the shift determination means 3 for the predetermined time.
The multiple shift detecting means 5 for detecting that a new shift has been determined, and the friction engagement device 1 is released when the multiple shift detecting means 5 detects that the new shift is determined. The delay updating means 6 is provided for setting the predetermined time for maintaining the above based on the new shift.

[0008]

Therefore, according to the present invention, when the shift determining means 3 determines the shift to the shift stage in which the engine brake frictional engagement device 1 is engaged, a predetermined time has elapsed from the time when the shift to the shift stage is instructed. In the meantime, the friction delay device 4 maintains the friction engagement device 1 in the released state. In this way, the time for which the frictional engagement device 1 is maintained in the released state can be determined based on the traveling state that includes at least one of the vehicle speed, the throttle opening, and the gear as a parameter, and as a result, Tie-up during downshifting is prevented, and the engagement of the frictional engagement device is excessively delayed to effectively prevent the shift shock described above.

Further, when a new shift determination is made during the above-mentioned predetermined time for maintaining the friction engagement device in the released state, the multiple shift detection means 5 detects this. In that case, the predetermined time for maintaining the friction engagement device 1 in the released state is
It is updated based on the running state at the time of a new shift determination, and as a result, the time for maintaining the frictional engagement device 1 in the released state becomes suitable for the actual shift, so that tie-up or engagement delay may occur. The shift shock can be effectively prevented.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is an overall control system diagram showing an embodiment of the present invention. An engine E to which an automatic transmission A is connected has an intake pipe 12 in which a main throttle valve 13 is provided.
And a sub-throttle valve 14 located upstream thereof. The main throttle valve 13 is connected to an accelerator pedal 15 and is opened / closed according to the amount of depression of the accelerator pedal 15. The sub-throttle valve 14 is opened and closed by a motor 16. An engine electronic control unit (E-ECU) 17 for controlling the motor 16 for adjusting the opening of the sub-throttle valve 14 and for controlling the fuel injection amount and ignition timing of the engine E is provided. There is. The electronic control unit 17 is mainly composed of a central processing unit (CPU), a storage unit (RAM, ROM), and an input / output interface. The electronic control unit 17 stores data for control as Engine (E /
G) Various signals such as rotational speed N, intake air amount Q, intake air temperature, throttle opening, vehicle speed, engine water temperature, and signals from brake switches are input.

In the automatic transmission A, the hydraulic control device 18 controls the shift and the lockup clutch, the line pressure, or the engagement pressure of a predetermined friction engagement device. The hydraulic control device 18 is configured to be electrically controlled, and also has first to third shift solenoid valves S1 to S3 for executing a shift and a first to third engine for controlling an engine braking state. 4 solenoid valve S4, linear solenoid valve SLT for controlling the line pressure, linear solenoid valve SLN for controlling the back pressure of the accumulator, linear for controlling the engagement pressure of a lock-up clutch or a predetermined friction engagement device A solenoid valve SLU is provided.

An electronic control unit (T-ECU) 19 for an automatic transmission that outputs a signal to these solenoid valves to control gear shift, line pressure, accumulator back pressure, etc.
Is provided. This automatic transmission electronic control unit 19
Is a central processing unit (CPU) and a storage device (RA
M, ROM) and an input / output interface, and the electronic control unit 19 has a throttle opening, vehicle speed, engine water temperature, a signal from a brake switch, a shift position, as data for control.
The signal from the pattern select switch, the signal from the overdrive switch, the signal from the C0 sensor that detects the rotational speed of the clutch C0, which will be described later, the signal from the C2 sensor that detects the rotational speed of the second clutch C2, and the automatic transmission Oil temperature, signals from the manual shift switch, etc. are input.

The electronic control unit 19 for the automatic transmission and the electronic control unit 17 for the engine are connected to each other so that data communication is possible, and the electronic control unit 17 for the engine transfers to the electronic control unit 19 for the automatic transmission. On the other hand, a signal such as the intake air amount per rotation (Q / N) is transmitted, and an instruction signal for each solenoid valve is sent from the automatic transmission electronic control unit 19 to the engine electronic control unit 17. A signal equivalent to, a signal instructing a shift speed, and the like are transmitted.

That is, the electronic control unit 19 for the automatic transmission
Is based on the input data and the map stored in advance, and the ON / OFF of the gear position and the lockup clutch is performed.
F, or the line pressure or the adjustment level of the engagement pressure is judged, and based on the judgment result, an instruction signal is output to a predetermined solenoid valve, and further judgment of fail or control based on it is performed. . In addition to controlling the fuel injection amount, the ignition timing, the opening degree of the sub-throttle valve 14, etc. based on the input data, the electronic control unit 17 for the engine also sets the fuel injection amount during the shift in the automatic transmission A. The output torque is temporarily reduced by reducing the amount, changing the ignition timing, or narrowing the opening of the sub-throttle valve 14.

FIG. 3 is a diagram showing an example of a gear train of the above-described automatic transmission A, and in the configuration shown here, it is configured to set five forward gears and one reverse gear. That is, the automatic transmission A shown here is used in the torque converter 20.
And a sub-transmission unit 21 and a main transmission unit 22. The torque converter 20 includes a lockup clutch 23.
The lock-up clutch 23 has a front cover 25 that is integrated with the pump impeller 24.
A member (hub) in which the turbine runner 26 and the turbine runner 26 are integrally attached
It is provided between 7 and. An engine crankshaft (not shown) is connected to a front cover 25, and a turbine runner 26 is connected to an input shaft 28.
Is connected to a carrier 30 of an overdrive planetary gear mechanism 29 that constitutes the auxiliary transmission unit 21.

The carrier 3 in this planetary gear mechanism 29
A multi-plate clutch C0 and a one-way clutch F0 are provided between 0 and the sun gear 31. The one-way clutch F0 is engaged when the sun gear 31 rotates forward relative to the carrier 30 (rotates in the rotation direction of the input shaft 28). Further, a multi-plate brake B0 for selectively stopping the rotation of the sun gear 31 is provided.
The ring gear 3 which is an output element of the subtransmission unit 21
2 is connected to an intermediate shaft 33 which is an input element of the main transmission unit 22.

Therefore, in the sub transmission unit 21, the entire planetary gear mechanism 29 rotates integrally when the multi-plate clutch C0 or the one-way clutch F0 is engaged, so that the intermediate shaft 33 has the same speed as the input shaft 28. It will rotate at low speed. Further, in the state where the brake B0 is engaged and the rotation of the sun gear 31 is stopped, the ring gear 32 is accelerated with respect to the input shaft 28 to rotate in the normal direction, and the high speed stage is established.

On the other hand, the main transmission section 22 is provided with three sets of planetary gear mechanisms 40, 50, 60, and their rotating elements are connected as follows. That is, the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 of the second planetary gear mechanism 50 are integrally connected to each other, and the ring gear 43 of the first planetary gear mechanism 40 and the carrier 52 of the second planetary gear mechanism 50 are connected. The third planetary gear mechanism 60 and a carrier 62 are coupled to each other, and the carrier 62 is coupled to an output shaft 65. Further, the ring gear 53 of the second planetary gear mechanism 50 is connected to the sun gear 61 of the third planetary gear mechanism 60.

In the gear train of the main transmission unit 22, it is possible to set a reverse gear and four gears on the forward side, and clutches and brakes therefor are provided as follows. First, the clutch will be described. The ring gear 53 and the third gear of the second planetary gear mechanism 50 which are connected to each other.
A first clutch C1 is provided between the sun gear 61 of the planetary gear mechanism 60 and the intermediate shaft 33, and the sun gear 41 of the first planetary gear mechanism 40 and the sun gear 51 and the intermediate shaft of the second planetary gear mechanism 50 are connected to each other. A second clutch C2 is provided between the first clutch 33 and the second clutch C3.

Next, the brake will be described. The first brake B1 is a band brake, and the sun gears 41 and 5 of the first planetary gear mechanism 40 and the second planetary gear mechanism 50 are used.
It is arranged to stop the rotation of 1. A first one-way clutch F1 and a second brake B2, which is a multi-disc brake, are arranged in series between the sun gears 41 and 51 (that is, the common sun gear shaft) and the casing 66. One way clutch F1 is sun gear 41,5
1 engages when trying to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 28). The third brake B3, which is a multi-disc brake, is the first planetary gear mechanism 4
It is provided between the zero carrier 42 and the casing 66. Then, as a brake for stopping the rotation of the ring gear 63 of the third planetary gear mechanism 60, the fourth brake B4, which is a multi-disc brake, and the second one-way clutch F2 are provided in the casing 6.
6 and 6 are arranged in parallel. The second one-way clutch F2 is adapted to be engaged when the ring gear 63 tries to rotate in the reverse direction.

In the above-described automatic transmission A, it is possible to set five forward speeds and one reverse speed by engaging and disengaging each clutch and brake as shown in the operation table of FIG. In FIG. 4, a circle indicates an engaged state, a circle indicates an engaged state during engine braking, a triangle indicates either engaged or disengaged, and a blank indicates a disengaged state.

Each gear stage shown in FIG. 4 is set according to the traveling range selected by operating a shift lever (not shown), and the position of the traveling range selected by the shift lever is shown in FIG. Are arranged as follows. That is, the reverse (R) range position is arranged following the parking (P) range position, and the neutral (N) range position is provided following the R range at a position diagonal to the arrangement direction. The drive (D) range position is arranged parallel to the N range with the arrangement direction of the P range position and the R range position, and the fourth speed range position is a direction orthogonal to these arrangement directions. It is placed in a bent position. Further, the third speed range position is arranged in a direction parallel to the arrangement direction of the N range and the D range with respect to the fourth speed range position, and the second speed range position is similar to the N range position with respect to the R range position. The low (L) range position is provided at a position having the same relationship as the fourth speed range position with respect to the D range position.

Among the driving ranges, the D range can achieve the 5 forward speeds shown in FIG. 4, whereas the 4th speed range does not have the 5th speed, which is the overdrive speed, and the 4 forward speeds. In addition, in the third speed range, up to the third speed can be achieved, in the second speed range, up to the second speed, respectively, and in the L range, only the first speed can be achieved. be able to.

The engine braking states in the first speed to the third speed can be achieved by engaging the friction engagement devices corresponding to the respective engine braking states. That is, FIG.
As shown in, the engine brake can be activated by engaging the fourth brake B4 at the first speed,
Further, by engaging the clutch C0 of the subtransmission unit 21 at the second speed and further engaging the first brake B1 at the third speed, the engine braking can be activated respectively. An example of a hydraulic circuit for that purpose is shown in FIG.

In FIG. 6, reference numeral 70 denotes a pressure control valve, which regulates the line pressure PL supplied through the line pressure oil passage 71 with a regulated value based on the signal pressure of the accumulator back pressure linear solenoid valve SLN. The output port 72 outputs to the input port 74 of the engine brake relay valve 73. The engine brake relay valve 73 is controlled by the fourth solenoid valve S4. That is, the fourth solenoid valve S4 is configured to drain the line pressure in the ON state, and close the drain port in the OFF state to output the signal pressure, and the signal pressure is supplied to the engine brake relay valve 73. As a result, the input port 74 communicates with the output port 75. And this output port 75
It is connected to the input port 77 of the 1-2 shift valve 76.

The operating state of the 1-2 shift valve 76 is as follows.
As shown in the upper side of FIG. 6, the input port 77 communicates with the first brake port 78 in the first speed, the neutral (N) range, and the reverse (R) range, and the input port at other gears. 77 is configured to communicate with the second brake port 79. Of these brake ports 78, 79, the first brake port 78
Is connected to the fourth brake B4 via a shuttle valve 80. Therefore, if the fourth solenoid valve S4 is turned off while the first speed is set, the hydraulic pressure regulated by the pressure control valve 70 is supplied to the fourth brake B4, and as a result, the engine brake can be activated. it can.

Reference numeral 81 in FIG. 6 indicates a 4-5 shift valve, and an input port 82 thereof has a manual valve 83.
D range port 84 of is connected. This 4-5 shift valve 81 has an input port 8 in the 1st to 4th speeds and the N range, as described below in FIG.
2 is configured to communicate with the output port 85,
The output port 85 is connected to the input port 87 of the C0 exhaust valve 86. C0 exhaust valve 8
Reference numeral 6 denotes a valve for selectively supplying hydraulic pressure to the clutch C0 of the auxiliary transmission unit 21, which is the fourth solenoid valve S.
When 4 is turned off and the signal pressure is supplied, the input port 87 communicates with the output port 88. The clutch C0 is connected to the output port 88. Therefore, if the fourth solenoid valve S4 is turned off in the second speed state, the 4-5 shift valve 81
And clutch C0 via C0 exhaust valve 86
The hydraulic pressure is supplied to and is engaged, and as a result, the engine brake can be applied in the second speed.

On the other hand, the second output port 79 of the 1-2 shift valve 76 is connected to the input port 90 of the 3-4 shift valve 89. This 3-4 shift valve 89
As shown in the upper side of FIG. 6, the input port 90 is the output port 9 in the first to third and N ranges.
It is configured to communicate with 1. The first brake B1 is connected to the output port 91. Therefore, if the fourth solenoid valve S4 is turned off in the state where the third speed is set, the hydraulic pressure regulated by the pressure control valve 70 causes the engine brake relay valve 73, the 1-2 shift valve 76 and the 3-4 It is supplied to the first brake B1 via the shift valve 89, and as a result, the first brake B1 is engaged and the engine brake can be activated.

The above-mentioned engine braking states in the third speed to the first speed are set by selecting the "3" range, the "2" range or the L range by a shift lever (not shown). In this case, tie-up occurs depending on the timing of engagement of the frictional engagement device for engine braking, so control is performed so that the timing of engagement of the frictional engagement device for engine braking is delayed. For example, in the case of downshifting from the 4th speed to the 3rd speed engine braking state, if the engagement timing of the first brake B1 is early with respect to the release of the second clutch C2, the sun gears 41, 51 are operated by the second clutch C2. This is fixed by the first brake B1 while rotating, and therefore the first brake B1 is maintained in the released state for a predetermined time to prevent such tie-up. Also, the time to maintain the released state is the time according to the running state,
In the case of multiple shifts in which downshifts based on two or more manual operations are performed within a shorter time, the frictional engagement device for engine braking is maintained in the released state in accordance with the last selected shift speed. .

FIG. 7 is a flow chart showing a control routine in the case where each shift speed is set by a manual shift operation. After the initial setting such as the processing of the input signal, the fourth speed or the fifth speed is set. It is judged whether or not it is being output (step 1). If the judgment result is "yes", it returns. If it is "no", it is judged in step 2 whether or not the third speed is being output. To do. If the result of the judgment is "yes", then the timer TMDS4
Start (step 3), and then the timer TMD
It is determined whether or not S4 has finished counting the predetermined time (step 4). If the counting of the time has not been completed, that is, if the predetermined time has not elapsed from the output of the shift, it is determined whether the shift to the second speed is output (step 5), If the result of the judgment is "no", the fourth solenoid valve S4 is turned on.
After performing (Step 6), the procedure returns to before Step 4. If the result of the determination in step 4 is "yes" due to the elapse of a predetermined time, the process proceeds to step 7 and the fourth
Turn off the solenoid valve S4 and return.

That is, when the manual downshift to the third speed is output, the fourth solenoid valve S4 is turned on until a predetermined time elapses from the shift output, so that the engine brake relay valve 73 described above is turned on. In, the communication between the input port 74 and the output port 75 is cut off. Therefore, the first brake B1 is maintained in the released state without being supplied with hydraulic pressure. Then, when a predetermined time has elapsed from the output of the shift, the fourth solenoid valve S4 is turned off and the input port 7 of the engine brake relay valve 73 is turned off.
4 and the output port 75 communicate with each other, so the first brake B
1 is engaged and engine braking is activated. As described above, while the first brake B1 is maintained in the released state, the second clutch C2 is released and the downshift to the third speed is completed. Up does not occur.

On the other hand, if the result of the determination in step 2 is "NO", the process proceeds to step 8 and it is determined whether or not a manual downshift to the second speed is output.
If the shift to the second speed is output, the timer TMD is used as in the case of the manual downshift to the third speed described above.
Start S4 (step 9), then timer T
It is determined whether the MDS 4 has finished counting the predetermined time (step 10). If the counting of the time has not been completed, that is, if the predetermined time has not elapsed from the output of the shift, it is determined whether the shift to the first speed is output (step 11), If the result of the determination is "No", the fourth solenoid valve S4
After turning ON (step 12), the process returns to the step before step 10. If the result of the determination in step 10 is "yes" due to the passage of a predetermined time, step 1
Proceed to step 2, turn off the fourth solenoid valve S4, and return.

Further, if the result of the determination in step 8 is "no", it means that the manual downshift to the first speed has been outputted. Therefore, in this case as well, the timer TMD
S4 is started (step 14), and then it is determined whether or not the timer TMDS4 has finished counting a predetermined time (step 15). If the counting of the time has not been completed, that is, if the predetermined time that has been set in advance has not elapsed from the output of the shift, it is determined whether the shift to the first speed is being output (step 15), If the result of the determination is “No”, the fourth solenoid valve S
After turning ON 4 (step 16), return to the step before step 15. If the result of the determination in step 15 is "yes" due to the elapse of a predetermined time, the routine proceeds to step 17, where the fourth solenoid valve S4 is turned off and the routine returns.

That is, in both the case of the manual downshift to the second speed and the case of the manual downshift to the first speed, the count value of the timer TMDS4 becomes a predetermined value and a predetermined time elapses. Until then, the fourth solenoid valve S4 is turned on to maintain the friction engagement device (clutch C0, fourth brake B4) for engine braking at each shift speed in the released state, so that tie-up can be prevented. it can.

Further, the time for maintaining the frictional engagement device for engine braking in the released state is set by mapping the running state such as each shift stage or shift stage at the time of shift output or throttle opening. An example of this is shown in FIG. Therefore, it is possible to prevent a shift shock caused by maintaining the friction engagement device for engine braking in a released state for an excessively long time.

In FIG. 7, if the result of the determination in step 5 is "yes", the process proceeds to step 9, and if the result of the determination in step 11 is "yes", then the step 1
Go to 4. That is, if the shift to the second speed is output while the timer TMDS4 is counting during the manual downshift to the third speed, the counts up to that point are canceled and the count of the timer TMDS4 for the second speed is canceled. Is newly started, and the fourth solenoid valve S4 is turned on during the counting to maintain the friction engagement device (clutch C0) for engine braking in the released state. Further, when the shift to the first speed is output while the timer TMDS4 for the second speed is counting, similarly, the counts up to that time are canceled and the count of the timer TMDS4 for the first speed is newly added. When the counting is started, the fourth solenoid valve S4 is turned on to keep the friction engagement device for engine braking (fourth brake B4) in the released state.

Fourth type of so-called multiple shift
The ON / OFF state of the solenoid valve S4 is shown in FIG. FIG. 9 shows an example of a case where the manual shift is made to the L range while the vehicle is traveling at the fifth speed of the D range, and the third shift is made at the time t0 when the D range is shifted to the L range.
The speed change output to the high speed is performed and the fourth solenoid valve S4 is set to the ON state.
A downshift to the second speed is output due to a change in the running state such as a decrease in vehicle speed. At this time point t1, the timer count is canceled and the timer TMDS4 newly starts counting time, but at time point t2 prior to the count-up, due to a change in the running state such as a decrease in vehicle speed, the first speed is reached. Downshift is output. Therefore, the counting of the timer TMDS4 is canceled again and the counting of the time by the timer TMDS4 is newly started. Then, at time t when the predetermined time for the first speed has elapsed
At 3, the fourth solenoid valve S4 is switched off and the engine braking is activated.

When so-called multiple manual downshifts are output in this way, the frictional engagement device for engine braking is controlled to be released for the final gear stage that is actually set. It is possible to reliably prevent tie-up in which the engine brake frictional engagement device is engaged while the engagement device is engaged.

It should be noted that the present invention is not limited to the above-described embodiment, and an automatic transmission other than the automatic transmission having the gear train shown in FIG. 3 and an automatic transmission having a hydraulic circuit other than the hydraulic circuit shown in FIG. It can also be applied to a shift control device for a machine. Therefore, the present invention is configured to control the friction engagement device for engine brake by controlling the fourth solenoid valve and to control the friction engagement device for engine brake to the released state for a predetermined time by other means. May be.

[0040]

As described above, according to the shift control device of the present invention, the frictional engagement device for the engine brake is released during the manual downshift for the predetermined time set according to the running state. Since the friction engagement device is engaged with the friction engagement device after that, it is possible to effectively prevent a shift shock due to tie-up or engagement of the friction engagement device with a delay. Also in the case of so-called multiple shift, the engine brake frictional engagement device is maintained in the released state according to the final shift output.
It is possible to effectively prevent gear shift shock by avoiding tie-up and delay in engagement of the friction engagement device.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention.

FIG. 2 is a block diagram schematically showing a control system of an embodiment of the present invention.

FIG. 3 is a diagram mainly showing a gear train of the automatic transmission.

FIG. 4 is a diagram showing an operation table for setting each shift speed.

FIG. 5 is a diagram showing an arrangement of shift positions for selecting each traveling range.

FIG. 6 is a diagram schematically showing a part of a hydraulic circuit.

FIG. 7 is a flowchart showing a control routine for maintaining a friction engagement device for engine braking in a released state during a manual downshift.

FIG. 8 is a diagram showing an example of a map in which a time period during which a frictional engagement device for engine braking is maintained in a released state is set according to a traveling state.

FIG. 9: ON / OFF of the fourth solenoid valve at the time of multiple shift
It is a time chart which shows change of an OFF state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Friction engagement device 2 Valve mechanism 3 Gear shift determination means 4 Engagement delay means 5 Multiple gear shift detection means 6 Delay update means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Tabata 1 Toyota-cho, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (72) Inventor Masahiko Ando 10, Takane, Fujii-cho, Aichi Prefecture Aisin AW Within the corporation

Claims (1)

[Claims] 1. A shift control device for an automatic transmission, comprising: a friction engagement device for engine brake; and a valve mechanism that is electrically controlled to selectively supply hydraulic pressure to the friction engagement device. A shift determining means for determining a shift to a shift stage to engage the engagement device; and, when a shift to the shift stage is determined, a predetermined time has elapsed after the shift to the shift stage is instructed. The engagement delay means for maintaining the friction engagement device in the released state, the multiple shift detecting means for detecting that the shift determining means newly makes a shift determination during the predetermined time, and the multiple shift detecting means. Delay change means for setting the predetermined time period for maintaining the friction engagement device in the released state based on the new shift when the shift detecting means detects that the new shift is determined. Is characterized by Shift control system for an automatic transmission.