JPH0531695B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a shift control device for an automatic transmission used in a vehicle such as an automobile, and more specifically, it has a gear transmission that switches between a plurality of gears,
The present invention relates to a shift control device that switches and sets gears according to a predetermined shift pattern depending on vehicle speed and the amount of depression of an accelerator pedal. [Prior Art] Automatic transmissions used in vehicles such as automobiles generally include a hydraulic torque converter and a gear transmission as an auxiliary transmission, and the gear transmission is capable of switching between multiple gears. A gear transmission with an overdrive stage is
In many cases, the gear is switched between four forward speeds and one reverse speed, including an overdrive speed. In a vehicle automatic transmission that has a gear transmission that switches between four forward speeds and one reverse speed, including an overdrive speed, the gear ratio (input rotation speed/output rotation speed) is small until the vehicle speed is low. In the drive stage, drive torque is generated because the torque converter's turbine rotational speed tends to be lower than the engine rotational speed, and during controlled operation when the accelerator pedal is released and the brake pedal is depressed, the above-mentioned drive occurs. It is known that when torque is generated, the wear of the brake pads of a vehicle brake becomes severe and the service life of the brake pads is shortened.
Therefore, the vehicle speed for downshifting from overdrive gear to third gear when the accelerator pedal is released should be set to a vehicle speed above a predetermined value at which the above-mentioned driving force is not generated. However, the vehicle speed when the accelerator pedal is released from the overdrive gear to the third gear, which is determined by the above-mentioned requirements, is generally in the medium vehicle speed range of 30 to 40 km/h, which is a vehicle speed range where the perceived shift shock is large. Therefore, if the vehicle speed for downshifting from the overdrive gear to the third gear is determined according to the requirements described above, the perceived shift shock when downshifting from the overdrive gear to the third gear will be large and the driving will be This creates a problem with comfort. The reason why the perceived shift shock is large in the medium speed range of 30 to 40 km/h is as follows.
This is believed to be because the gear shift is performed relatively rapidly compared to when the vehicle is in a high vehicle speed range, and the amount of change in engine speed is larger than when it is in a low vehicle speed range. The generation of drive torque as described above becomes a problem only when the brake pedal is depressed due to wear of the brake pads of the vehicle brake, and when the vehicle is coasting when both the accelerator pedal and the brake pedal are not depressed. When driving, the generation of drive torque as described above does not become a problem, and at this time, in order to reduce the perceived shift shock, it is necessary to downshift from overdrive gear to third gear when the accelerator pedal is released. The vehicle speed may be a relatively low vehicle speed that generates drive torque but does not cause a large perceived shift shock. By the way, in an automatic transmission having a gear transmission device that switches between four forward speeds and one reverse speed including an overdrive speed, it is necessary to control the engagement and disengagement of a friction engagement device in conjunction with each other when changing gears. In order to avoid the need for strict timing control, the engine drive power is transmitted through a one-way clutch in the first and second gears, and therefore the overdrive and third gears are transmitted through a one-way clutch. An engine braking effect can be obtained in the first and second gears, but the engine braking effect cannot be obtained in the first and second gears. Therefore, when the overdrive gear is downshifted to the second gear, which does not have an engine braking effect, the engine speed does not increase rapidly even if the gear ratio increases, and therefore the accelerator pedal Even if the downshift vehicle speed from the overdrive gear to the second gear when the depression is released is at the above-mentioned medium vehicle speed, a shift shock does not occur. Incidentally, automatic transmissions configured to perform special speed change control during braking operation are disclosed in Japanese Patent Application Laid-open Nos. 56-39349, 46150-1980, 58519-1977, and 57-1982.
This has already been proposed in No. 95222 and Japanese Patent Application Laid-Open No. 179460/1982, but these do not take into account the above-mentioned phenomenon. [Problems to be Solved by the Invention] The present invention provides a solution to the problem that, when the accelerator pedal is released and the brake pedal is depressed while the vehicle is running in a high-speed gear, the wheels are activated as the vehicle speed decreases. An automatic transmission for a vehicle that is improved to reliably avoid a situation in which the engine is driven even when the vehicle is in a braked state, and to avoid premature wear of the brake pads for braking the vehicle. Our objective is to provide a speed change control device. [Means for Solving the Problems] According to the present invention, the above-mentioned problems are solved by having a basic speed change pattern that determines the gears to be executed in accordance with the running state of the vehicle, and changing the speed based on the basic speed change pattern. In a shift control device that controls the gears of a vehicle automatic transmission, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, torque is transferred from the engine side to the wheels through the automatic transmission. This is achieved by a shift control device characterized in that it has a control means that performs a downshift with priority over a shift determination based on the basic shift pattern before transmission occurs. In this case, it is preferable that the downshift is performed in priority to the gear shift determination based on the basic shift pattern at a gear position that does not produce an engine braking effect. Furthermore, in this case, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, the gear shift based on the basic gear shift pattern is performed before torque is transmitted from the engine side to the wheels through the automatic transmission. Even if the brake pedal is released after the downshift is performed in priority to the judgment, as long as the accelerator pedal is not depressed, the downshift according to the basic shift pattern occurs to the gear position achieved by the downshift. It is preferable that the gear position is maintained until the vehicle speed decreases to the vehicle speed. Furthermore, in this case, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, the gear shift based on the basic gear shift pattern is performed before torque is transmitted from the engine side to the wheels through the automatic transmission. A downshift is performed with priority over the judgment, and even when the brake pedal is subsequently released and the accelerator pedal is depressed, the gear position achieved by the downshift is maintained until a predetermined period of time has elapsed. preferable. [Operations and Effects of the Invention] According to the shift control device for an automatic transmission for a vehicle of the present invention as described above, the automatic transmission basically determines the gear stage to be executed in accordance with the running state of the vehicle. However, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, if the automatic transmission is set to a high speed gear, the reduction gear ratio will be compared. When the vehicle speed decreases and torque is transmitted from the engine side to the wheels through the automatic transmission, the automatic transmission takes priority over the shift decision based on the basic shift pattern. By downshifting and increasing the reduction gear ratio, a situation in which the wheels are driven by the engine even though the brakes are applied is prevented from occurring. Additionally, in this case, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, a gear shift decision is made based on the basic gear shift pattern before torque is transmitted from the engine side to the wheels through the automatic transmission. After a downshift has been performed in priority to , even if the brake pedal is released, as long as the accelerator pedal is not depressed, the vehicle speed at which the downshift according to the basic shift pattern occurs to the gear position achieved by the downshift. If the gear position is maintained until the vehicle speed decreases to
Automatically returns to shifting according to the basic shifting pattern,
Transient shift instability does not occur. Furthermore, in this case, when the vehicle is running with the accelerator pedal released and the brake pedal depressed, the gear shift based on the basic shift pattern is performed before torque is transmitted from the engine side to the wheels through the automatic transmission. A downshift is performed with priority over the judgment, and even when the brake pedal is released and the accelerator pedal is depressed, the gear position achieved by the downshift is maintained until a predetermined period of time has elapsed. , favorable acceleration performance can be obtained. [Example] The present invention will be described in detail below with reference to the accompanying drawings. The attached drawing schematically shows the configuration of an apparatus for carrying out the method for controlling an automatic transmission for a vehicle according to the present invention. The automatic transmission 1 is well known in itself, and is a three-element, single-stage, two-phase type general fluid transmission having an input shaft 2 drivingly connected to the output shaft of an engine 100, a pump, a turbine, and a starter. The gear transmission 7 has a hydraulic torque converter 3 and a gear transmission 7 as an auxiliary transmission. The input shaft and the output shaft are drivingly connected to a plurality of gears that drive and connect the output shaft 6 that is drivingly connected to the drive wheel at one speed ratio selected from a plurality of speed ratios. It is designed to be able to switch between a neutral stage and a neutral stage that separates from the relationship. The gear transmission 7 includes a carrier 8 connected to the input shaft 5, a planetary pinion 9 supported by the carrier, a sun gear 10 and a ring gear 11 meshing with the planetary pinion, and a carrier 8 and a sun gear 10. A one-way clutch (F ₀ ) 12 provided between the two, and an OD clutch (C ₀ ) that selectively connects the carrier 8 and sun gear 10.
13, and an OD brake (B ₀ ) 1 that selectively fixes the sun gear 10 to the transmission case.
4, which is used as an overdrive device in this gear transmission 7. The gear transmission 7 includes a sun gear 15, two ring gears 16 and 17, a planetary pinion 18 that is located between the sun gear 15 and the ring gear 16 and meshes with both, and a planetary pinion 18 that is in mesh with the sun gear 15 and the ring gear 17. It has another planetary pinion 19 that meshes with the two planetary pinions, and carriers 20 and 21 that rotatably support the planetary pinions 18 and 19, respectively. Ring gear 16 is supported by an intermediate shaft 22, which is adapted to be selectively coupled in torque transmission relationship to ring gear 11 by a forward clutch (C ₁ ) 23. The sun gear 15 is supported by an intermediate shaft 24, and the intermediate shaft 24 is connected to the ring gear 1 by a direct clutch (C ₂ ) 25.
1 in a torque transmission relationship. The intermediate shaft 24 is a one-way clutch (F ₁ ) 2 that is locked when the engine is driven.
A band is selectively fixed to the transmission case and selectively prevented from rotating by a direct connection mechanism between the second brake (B 2 ) 6 and the second brake (B ₂ ) 27, and a band provided in parallel to the series connection mechanism. A second coast brake (B ₁ ) 28 of the type is selectively fixed to the transmission case separately from the series connection mechanism to selectively prevent its rotation. carrier 21
is fixed to the transmission case and prevented from rotating only when the engine is driven by a one-way clutch (F ₂ ) 29 that becomes locked when the engine is running, and is prevented from rotating by a fast & reverse brake (B ₃ ) 30. The rotation case is selectively fixed to the rotation case so that its rotation can be selectively prevented. Both the ring gear 17 and the carrier 20 are connected to the output shaft 6. Each of the clutches 13, 23, 25 and brakes 14, 27, 28, 30 of the gear transmission 7 is driven by a hydraulic servo device (not shown), and each hydraulic servo device is operated by a hydraulic control device 31. It's getting old. The hydraulic control device 31 includes two electromagnetic valves 32 and 33.
and manual shift lever 4 operated by hand.
1, and various hydraulic control valves and speed change valves (not shown). The gear transmission 7 is controlled to switch between a plurality of gears and a neutral gear by controlling the supply and discharge of hydraulic pressure to the gears. This hydraulic control device 31
The basic structure of this has already been proposed in Japanese Patent Application No. 55-69110 by the same applicant as the present applicant, and if a more detailed explanation of this hydraulic control device is required, please refer to Japanese Patent Application No. 55-69110. Please refer to the specification and drawings of No. The opening and closing of the solenoid valves 32 and 33 is performed by electric signals individually applied to each solenoid valve by an electronic control unit 36. The electronic control device 36 has an arithmetic processing function such as a microcomputer, and receives information regarding the vehicle speed from the vehicle speed sensor 37 and information regarding the throttle opening of the internal combustion engine 100 from the throttle opening sensor 38, in other words, the amount of depression of the accelerator pedal. Information regarding whether or not the brake for braking the vehicle is in operation is provided from the brake switch 39, and an on-off electrical signal is individually output to each of the solenoid valves 32 and 33 according to the information. I'm starting to do that. By individually applying ON or OFF signals to the two solenoid valves 32 and 33, the two solenoid valves open and close individually, and thereby the clutches 13, 23, 25 of the gear transmission 7 and the brake 1
4, 17, 28, and 30 are operated in combinations as shown in the table below, and the gears are switched between a plurality of gears including four forward gears including an overdrive gear and one reverse gear. Ru.

[Table] In this list, ○ mark indicates that the relevant clutch or brake is engaged, × mark indicates that the relevant clutch or brake is released, and △ mark indicates that the relevant one-way clutch or brake is engaged. It is engaged (locked) when the vehicle is driven by the engine, and released (free) during engine braking, when the engine is driven from the vehicle. Note that in the L range, the second gear is not upshifted, and only the first gear is downshifted from the second gear. By operating the clutch and brake in the above-mentioned combination, in the D range, the overdrive stage and third gear have an engine braking effect, and the second gear and first gear have an engine braking effect. does not play. FIG. 2 shows a basic shift pattern depending on the vehicle speed and throttle opening in the D range. In this Fig. 2, upshift line 1→2 is an upshift line that changes from the first gear to the second gear, and conversely, the upshift line 1←2 is the upshift line that changes from the first gear to the second gear. This is the downshift line that switches to first gear, and similarly upshift line 2→
3 and downshift line 2←3 are the upshift line and downshift line between the second and third gears, respectively, and the upshift line 3→O/D and the downshift line 3←O/ D is an upshift line and a downshift line between the third gear and the overdrive gear (fourth gear), respectively. By switching the gear position of the gear transmission 7 according to this shift pattern, an upshift is performed in response to an increase in vehicle speed at a constant throttle opening, and at a constant vehicle speed, an upshift is performed as the vehicle speed increases. A downshift is performed in response to the increase. Next, with reference to the flowchart shown in FIG. 3, the manner in which the speed change control method for an automatic transmission for a vehicle according to the present invention is carried out will be explained. When the internal combustion engine is started, step 1 is executed, and in step 1, as initialization, the flag F is converted to 0 and the counter is reset. After step 1, the process proceeds to step 2, and in step 2, the gear stage S _x is determined according to the vehicle speed V and the throttle opening according to the basic shift pattern shown in FIG. be exposed. The first vehicle speed _V1 , which is the overdrive gear → third gear downshift vehicle speed when the accelerator pedal is released from the overdrive gear according to the basic shift pattern, is set as shown in Fig. 4 in order to reduce the perceived shift shock. As shown in , when the accelerator pedal is released in the overdrive stage, the torque converter 3
Lower than the driving torque generation limit vehicle speed V ₀ b in the overdrive stage where the turbine rotation speed is equal to the idle rotation speed of the internal combustion engine, and equal to or equal to the similar driving torque generation limit vehicle speed V ₃ b in the third gear. The vehicle speed is set to a higher speed. In step 3, the gear stage S _x determined in step 2, or in step 8 or step 11 is
The gear position determined in step S is stored in the storage device as the control gear position S. After step 3, the process proceeds to step 4, in which it is determined whether the throttle valve is fully closed. When it is determined in step 4 that the throttle valve is fully closed, that is, when the accelerator pedal has been released, the process proceeds to step 5; on the other hand, when it is determined that the throttle valve is not fully closed, that is, when the accelerator pedal has been released, If the accelerator pedal is depressed, proceed to step 13. In step 5, it is determined whether the current gear is an overdrive gear. If the current gear position is the overdrive position, the process proceeds to step 6, whereas if the current gear position is not the overdrive position, the process proceeds to step 17. In step 6, it is determined whether the brake for braking the vehicle is on, that is, whether the brake pedal is being depressed. When the brake is on, that is, the brake pedal is depressed, the process proceeds to step 7, whereas when the brake is not on, that is, the brake pedal is released, the process proceeds to step 17. Step 7 is an overdrive stage and is a step executed during braking operation when the accelerator pedal is released and the brake pedal is depressed. In step 7, the vehicle speed is set to the third vehicle speed _V3.
A determination is made as to whether the value is greater than or not. When V≧V ₃ , proceed to step 8; on the other hand, when V≧
If not V ₃ , proceed to step 10. third vehicle speed
V ₃ is an overdrive stage during coasting →
First vehicle speed V ₁ which is the third gear downshift vehicle speed
The vehicle speed is considerably higher than that of the conventional automatic transmission for passenger cars, which is set at a high vehicle speed of 50 km/h or more. In step 8, during braking operation when the gear position is the overdrive position, the vehicle speed is set to the third vehicle speed _V3 .
This step is executed when the above is the case, and in this step 8, the control gear S is changed to the third gear S ₃
This is then written to the storage device in step 3. After step 8, the program proceeds to step 9, in which flag F is converted to 1. Flag F is a flag for executing speed change control during braking operation. After step 9, proceed to step 20. In step 10, the gear is in the overdrive gear, braking operation is in progress, and the vehicle speed is at the third vehicle speed _V3 .
In step 10, it is determined whether the vehicle speed V is smaller than the second vehicle speed _V2 . When V≦V ₂ , the process proceeds to step 11, and when V≦V ₂ does not hold, the process proceeds to step 20. As shown in FIG. 4, the second vehicle speed V ₂ is the time when the turbine rotation speed of the torque converter 3 reaches the idle rotation speed N ₁ of the internal combustion engine when the accelerator pedal is released in the overdrive stage. The vehicle speed is equal to or higher than the drive torque generation limit vehicle speed V ₀ b of the overdrive stage, and this second vehicle speed V ₂ is equal to or higher than the first vehicle speed
higher than V ₁ and lower than the third vehicle speed V ₃ . Step 11 is a step that is executed when the gear is in overdrive, controlled operation is being carried out, and the vehicle speed is not higher than the second vehicle speed _V2 .
In step 11, the control gear S is set to the second gear _S2 , and this is written in the storage device in step 3. After step 11, proceed to step 12, and step
At step 12, the flag F is converted to 1. After step 12, proceed to step 20. Step 13 is a step executed during load operation when the accelerator pedal is depressed, and in step 13, it is determined whether flag F is 1 or not. When F=1, step
Proceed to step 14; on the other hand, if F is not 1, proceed to step 20. In step 14, the count value C of the counter
It is done to count one up. After step 14, proceed to step 15, and then
At step 15, it is determined whether the count value C of the counter is greater than the set count value Cset.
When C≧Cset, the process proceeds to step 16, whereas when C≧Cset, the process proceeds to step 14. In step 16, a predetermined time determined by the set count value Cset of the counter has elapsed from the time when the throttle valve changes from fully closed to not fully closed, that is, from the time when the accelerator pedal is depressed. This step is executed later, and in step 16, the flag F is converted to 0 and the counter is reset. After step 16, proceed to step 2. Step 17 is a step executed during coasting, including when the gear position is in the overdrive position. In step 17, it is determined whether flag F is 1 or not. When F=1, the process proceeds to step 18, whereas when F=1, the process proceeds to step 20. Step 18 is a step executed when the vehicle shifts to coasting operation after braking in the overdrive stage, and in step 18, it is determined whether the vehicle speed is smaller than the deceleration control release vehicle speed Vc. will be held. If V≦Vc, proceed to step 19, whereas if V≦Vc, proceed to step 20.
Proceed to. The deceleration control release vehicle speed Vc may be a vehicle speed equal to the downshift vehicle speed from third gear to second gear when the accelerator pedal is released. In step 19, flag F is converted to zero. Step 19 is followed by Step 20
Proceed to. In step 20, the solenoid valves 32 and 3 are operated according to the control gear S stored in the storage device in step 3.
3 solenoid drive control is performed. As a result, the gear position of the gear transmission 7 is switched to the control gear position S. After step 20, proceed to step 21. In step 21, it is determined whether flag F is 1 or not. When the flag F=1, the process proceeds to step 3; on the other hand, when the flag F=1, the process proceeds to step 2. By performing the shift control according to the flowchart as described above, a large sensation of shock is generated according to the basic shift pattern during coasting operation in which the accelerator pedal and the brake pedal are released when the shift gear is in the overdrive gear. During braking operation, when a downshift to the third gear is performed at the first vehicle speed of V ₁ , and the gear is in overdrive, the accelerator pedal is released and the brake pedal is depressed. If the vehicle speed at the start of the braking operation is lower than the third vehicle speed _V3 , no driving torque is generated to reduce wear on the brake pads.Avoiding the occurrence of a large perceived shift shock at the second vehicle speed _V2 . Therefore, the third gear is skipped and a downshift is performed to the second gear, which does not have an engine braking effect.If the vehicle speed at the start of braking operation is higher than the third vehicle speed _V3 , the braking effect of the vehicle is increased. A downshift is immediately performed to third gear, which provides an engine braking effect. When the braking operation is performed in the overdrive stage and the downshift is made to the second or third gear as described above, that is, when the shift control during braking operation is executed, the flag F becomes 1. As a result, as long as the accelerator pedal is not depressed, whether the brake pedal is maintained or released, the process starts from step 4, passes through steps 5 and 17, and then returns to step 18.
As a result, even if the brake pedal is released, the gear position is maintained until the vehicle speed decreases to the deceleration shift control release vehicle speed Vc. Further, when the accelerator pedal is depressed while the above-described shift control during braking operation is being executed, the process proceeds from step 4 to step 13, and the process proceeds to step 13.
By executing steps 14, 15, and 16, even if the accelerator pedal is depressed, the gear position will not be changed immediately, that is, an upshift will not be performed at the same time as the accelerator pedal is depressed, and By executing step 2 after a predetermined time has elapsed since the accelerator pedal is depressed, the gear position S _x is determined based on the basic shift pattern shown in FIG. 2 according to the vehicle speed and throttle opening. At this time, the gear stage can be switched for the first time after the shift control during braking operation. FIG. 5 is a flowchart showing another embodiment of the method for controlling the speed change of an automatic transmission for a vehicle according to the present invention. . In such embodiments,
A step 22 is provided, the step being step 4.
This is executed when it is determined that the throttle valve is fully closed. In step 22, it is determined whether the flag F is 1 or not. If F=1, step 5 is skipped and the process proceeds to step 6.
When the value is not equal to 1, the process proceeds to step 5. Therefore, if a downshift is made to the third gear due to braking in the overdrive gear, the third gear will be shifted from step 4 to step 22 and step 22 if procedural braking is being performed. By proceeding to step 7 through step 6, the vehicle speed is maintained until it decreases to the second vehicle speed _V2 , and when the vehicle speed falls below the second vehicle speed _V2 , the process proceeds from step 10.
By proceeding to 11, the gear is further downshifted from the third gear to the second gear, and generation of drive torque while the brake pedal is being depressed is avoided. In addition, in the case of downshifting from the third gear to the second gear under braking operation as described above, the vehicle speed is determined to be equal to or higher than _V3 , which is the driving torque limit vehicle speed of the third gear. The first vehicle speed V ₁ may be the first vehicle speed V 1 . Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to these, and it is understood that various embodiments may be made within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram schematically showing one embodiment of a vehicular automatic transmission that implements the speed change control method according to the present invention and a speed change control device used to implement the speed change control method, and FIG. 1 is a graph showing an example of a basic shift pattern of an automatic transmission for a vehicle, FIG. 3 is a flowchart showing an implementation outline of a shift control method for an automatic transmission for a vehicle according to the present invention, and FIG. 4 is a graph showing an example of a basic shift pattern of an automatic transmission for a vehicle. FIG. 5 is a graph showing the relationship between engine speed and vehicle speed, and is a flowchart showing another embodiment of the method for controlling the speed change of an automatic transmission for a vehicle according to the present invention. DESCRIPTION OF SYMBOLS 1... automatic transmission, 2... input shaft, 3... hydraulic torque converter, 5... shaft, 6... output shaft, 7... gear transmission, 8... carrier, 9... planetary pinion, 10... sun gear, 11... ring gear , 12...
One-way clutch, 13...OD clutch, 14
...OD brake, 15...Sun gear, 16,17...
Ring gear, 18, 19...planetary pinion,
20, 21...Carrier, 22...Intermediate shaft, 23...Forward clutch, 24...Intermediate shaft, 25...Direct clutch, 26...One-way clutch, 27
...Second brake, 28...Second coast brake, 29...One-way clutch, 30...First & reverse brake, 31...Hydraulic control device, 32, 33...Solenoid valve, 36...Electronic control device,
37... Vehicle speed sensor, 38... Throttle opening sensor, 39... Brake switch, 41... Manual shift lever.

Claims (1)

[Scope of Claims] 1. A shift control device that has a basic shift pattern that determines the gears to be executed in accordance with the running state of the vehicle and controls the gears of an automatic transmission for a vehicle based on the basic shift pattern. When the vehicle is running with the accelerator pedal released and the brake pedal depressed, a shift decision based on the basic shift pattern is made before torque is transmitted from the engine to the wheels through the automatic transmission. A speed change control device characterized by having a control means for performing a downshift with priority. 2. In a shift control device that has a basic shift pattern that determines the gears to be executed in response to the running condition of the vehicle and controls the gears of an automatic transmission for a vehicle based on the basic shift pattern, the accelerator pedal When the vehicle is running with the brake pedal depressed and the brake pedal depressed, the engine braking effect is applied prior to the transmission of torque from the engine to the wheels through the automatic transmission, taking priority over the shift decision based on the basic shift pattern. 1. A speed change control device comprising a control means for downshifting to a gear position that does not provide the desired speed. 3. In a shift control device that has a basic shift pattern that determines the gears to be executed in accordance with the running condition of the vehicle and controls the gears of an automatic transmission for a vehicle based on the basic shift pattern, the accelerator pedal When the vehicle is running with the brake pedal depressed and the brake pedal depressed, a downshift is performed prior to the transmission of torque from the engine to the wheels through the automatic transmission, giving priority to the shift decision based on the basic shift pattern. Even if the brake pedal is released and the accelerator pedal is not depressed, the shift gear will remain in the gear position achieved by the downshift until the vehicle speed decreases to a speed at which a downshift according to the basic shift pattern occurs. 1. A speed change control device comprising control means for maintaining. 4. In a shift control device that has a basic shift pattern that determines the gears to be executed in accordance with the running condition of the vehicle and controls the gears of an automatic transmission for a vehicle based on the basic shift pattern, the accelerator pedal When the vehicle is running with the brake pedal depressed and the brake pedal depressed, a downshift is performed prior to the transmission of torque from the engine to the wheels through the automatic transmission, giving priority to the shift decision based on the basic shift pattern. A shift control device comprising control means for maintaining the gear position achieved by the downshift until a predetermined time period elapses when the brake pedal is released and the accelerator pedal is depressed.