JP2002323130A - Shift control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit off-upshifting only when a driver has a stopping intention of a vehicle by predicting whether or not the driver has the stopping intention of the vehicle. SOLUTION: This device is provided with a stoppage intention prediction means for predicting whether or not a closing operation of an accelerator is due to an intention of stopping the vehicle by subsequently stopping on the brake. When the closing operation of the accelerator is predicted to be due to the stopping intention of the driver by the stopping intention prediction means, a shift inhibition means for inhibiting an up-shift is provided. Because the off-upshifting is inhibited when predicting that the driver has the stopping intention, the off-upshifting is inhibited and the generation of an event for imparting unnatural feeling to the driver can be prevented also when the driver has no stopping intention. When the driver has intention of stopping the vehicle, the off-upshifting is inhibited, and thereby a busy shift, in which the up-shift is performed by the closing operation of the accelerator and a down-shift is performed by a succeeding braking operation is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission mounted on an automobile, and more particularly, to a shift control device applied to an automatic transmission that performs a shift by controlling a friction engagement element. .

[0002]

2. Description of the Related Art Normally, when a driver closes an accelerator and then steps on a brake, an upshift called off-up is first performed according to a normal shift map. , A downshift is performed.

[0003] Further, at the time of a downshift that occurs when the driver steps on the brake, a downshift point that occurs during deceleration of the vehicle, that is, a coast down point, is changed in accordance with the deceleration of the vehicle (in all cases, a normal downshift). A technique for preventing the generation of shocks and rattling due to the engine straddling the driving / non-driving state at the time of the downshift has been conventionally employed.

[Problems to be solved by the invention]

In this case, the driver closes the accelerator,
When the brake is subsequently applied, a map for coast down control is adopted for a downshift caused by the brake operation. As described above, the map is set on the higher vehicle speed side than the downshift point according to the normal shift map, so that it is 3-2 down from the 2-3 off-up point according to the normal shift map. The vehicle speed may be higher at the shift point.

[0005] Then, immediately after the driver closes the accelerator and performs an upshift, a downshift accompanying the brake operation is performed, causing a busy shift and giving the driver an uncomfortable feeling.

Therefore, it is conceivable to always prohibit the off-up shift which occurs when the driver performs the accelerator closing operation. However, prohibiting the off-up more than necessary requires the driver to close the accelerator at a high vehicle speed. In this case, too, an upshift is not performed, and a low gear is maintained, which in turn causes the driver to feel uncomfortable.

Therefore, the present invention predicts whether or not the driver intends to stop the vehicle, and prohibits the off-up shift only when the driver intends to stop the vehicle. It is an object of the present invention to provide a shift control device for an automatic transmission in which an off-up shift is performed and an off-up shift is not unnecessarily prohibited.

[0008]

According to the present invention, an input shaft (3) to which power from an engine output shaft (13) is input and an output shaft (14a, 14) connected to wheels.
b) and a plurality of friction engagement elements (C1 to C3, B1 to B5) for changing the power transmission path between the input shaft and the output shaft.
And a shift control means (21, SL) for performing a shift operation by appropriately controlling the plurality of friction engagement elements.
S, SLU), and the shift control device of the automatic transmission in which the driver performs an upshift to a predetermined shift speed by closing the accelerator by the driver, the accelerator closing operation then stops the vehicle by depressing a brake. Stop intention estimating means (21c,
And the step S2) of the off-up shift control program PRO shown in FIG. 5 is provided, and when the stop intention estimating means predicts that the closing operation of the accelerator is due to the driver's intention to stop, the predetermined gear position is determined. Shift prohibition means (21c, and step S22 of the off-up shift control program PRO in FIG. 5) for prohibiting an upshift to the vehicle.

According to a second aspect of the present invention, the stop intention estimating means is configured to determine that the intention to stop is higher than a predetermined value (output_CD) when the output shaft speed (ie, the vehicle speed No) of the transmission after the accelerator operation is closed. It is configured to predict that there is something.

According to a third aspect of the present invention, the stop intention estimating means includes a throttle opening (th) after the accelerator is closed.
Is, when the value is equal to or smaller than a predetermined value (th_guard), it is predicted that there is an intention to stop.

According to a fourth aspect of the present invention, the speed change inhibiting means includes:
When the accelerator is depressed, the shift operation is inhibited from being prohibited until the input torque (Tin) from the engine exceeds a predetermined value (inT guard).

According to a fifth aspect of the present invention, the shift prohibition control means includes: when the accelerator is depressed, the input torque (Tin) from the engine exceeds a predetermined value (inT guard);
And the throttle opening (th) is a predetermined value (th_guard_hi)
The prohibition of the shift operation is maintained until the time exceeds

[0013]

According to the first aspect of the present invention, the stopping intention estimating means predicts whether or not the driver has an intention to stop the vehicle. Since the shift prohibition means prohibits the off-up shift, the off-up shift is prohibited even when there is no intention to stop, and it is possible to prevent a situation that gives a feeling of strangeness to the driver.

If the driver intends to stop the vehicle, off-up shifting is prohibited, so that the upshift is performed by closing the accelerator, and the downshift is performed by subsequent brake operation. Is prevented.

According to the present invention, the output shaft rotation speed of the transmission after the operation of closing the accelerator, that is, the vehicle speed (No)
Is smaller than or equal to a predetermined value (output_CD), it is predicted that there is a will to stop, and off-up shifting is prohibited. Therefore, when the vehicle speed is high, it can be predicted that there is no intention to stop the vehicle. Accordingly, it is possible to prevent a situation in which the off-up shift is prohibited by the shift prohibiting means in a high vehicle speed state, and shift control without a sense of incongruity can be performed.

According to the third aspect of the present invention, only when the throttle opening (th) after the accelerator is closed is equal to or less than a predetermined value (th_guard), it is predicted that the driver intends to stop, and the vehicle is turned off. Since shifting is prohibited, when the throttle opening is high and there is no intention to stop the vehicle, off-up shifting is not prohibited, and shift control without a sense of incongruity is possible.

According to the present invention, when the accelerator is depressed, the prohibition of the shift operation is maintained until the input torque (Tin) from the engine exceeds a predetermined value (inT guard). Therefore, unless the accelerator is depressed to some extent, the off-up shift is prohibited, and even if the brake operation is performed after the accelerator is closed,
Unnecessary coast-down control is prevented from occurring carelessly.

According to the fifth aspect of the present invention, even when the driver normally performs the closing operation of the accelerator and the throttle opening is closed earlier, the input torque of the engine decreases with a delay. Even if the input torque is in the off-up shift prohibited area (OUPR),
A state occurs in the area where the prohibition of the off-up shift is released (the area equal to or more than inT guard). In this case, since chattering occurs, in the off-up shift operation, the input torque (Tin) from the engine exceeds the predetermined value (inT guard) and the throttle opening (th) becomes the predetermined value (th_guard_h
Prohibit until i) is exceeded. Thus, it is possible to realize an appropriate off-up shift prohibition state and a prohibition release state.

The reference numerals in parentheses are for comparison with the drawings, but do not affect the configuration of the present invention at all.

[0020]

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

FIG. 1 is a block diagram showing an example of an electric control circuit of an automatic transmission to which the present invention is applied, FIG. 2 is a skeleton diagram showing a mechanical portion of the automatic transmission to which the present invention can be applied, and FIG. FIG. 4 is a diagram showing the operation of each frictional engagement element.
Means re-grip of the friction engagement element (clutch-to-clutch)
FIG. 5 is a diagram schematically showing a hydraulic circuit related to a gear shift based on FIG.
Flowchart showing an off-up shift control program,
FIG. 6 is a diagram showing an example of a shift map near the off-up shift prohibition region.

The five-speed automatic transmission 1 is, as shown in FIG.
A torque converter 4, a three-speed main transmission mechanism 2, a three-speed auxiliary transmission mechanism 5, and a differential 8 are provided, and these parts are housed in a case integrally connected to each other. The torque converter 4 includes a lock-up clutch 4a. The input shaft 3 of the main speed change mechanism 2 is transmitted from the engine crankshaft 13 through an oil flow in the torque converter or through a mechanical connection by the lock-up clutch. To enter. Then, the first shaft 3 (specifically, the input shaft) arranged in alignment with the crankshaft, and the second shaft 6 (counter shaft) and the third shaft ( Left and right axles 14a, 14b are rotatably supported, and a valve body is disposed outside the case.

The main transmission mechanism 2 has a planetary gear unit 15 comprising a simple planetary gear 7 and a double pinion planetary gear 9. The simple planetary gear 7 is a carrier that supports a sun gear S1, a ring gear R1, and a pinion P1 meshing with these gears. The double pinion planetary gear 9 includes a sun gear S2, a ring gear R2, and a pinion P meshing with the sun gear S2.
2 and a common carrier CR that supports the pinion P3 meshing with the ring gear R2 together with the pinion P1 of the simple planetary gear 7.

The input shaft 3 interlocked from the engine crankshaft 13 via the torque converter 4
Can be connected to the ring gear R1 of the simple planetary gear 7 via the first (forward) clutch C1, and can be connected to the sun gear S1 of the simple planetary gear 7 via the second (direct) clutch C2. The sun gear S2 of the double pinion planetary gear 9
Can be directly locked by the first brake B1, and can be locked via the first one-way clutch F1.
It can be locked at 2. Furthermore, the ring gear R2 of the double pinion planetary gear 9 is connected to the third brake B3 and the second gear B2.
Can be locked by the one-way clutch F2. Further, the common carrier CR is connected to a counter drive gear 18 serving as an output member of the main transmission mechanism 2.

On the other hand, the sub-transmission mechanism 5 moves the output gear 1 toward the rear side in the axial direction of the counter shaft 6 constituting the second shaft.
6, a first simple planetary gear 10 and a second simple planetary gear 11 are arranged in this order, and the counter shaft 6 is rotatably supported by an integrated case via a bearing. The first and second simple planetary gears 10, 11 are of Simpson type.

Further, the first simple planetary gear 10
Means that the ring gear R3 is the counter drive gear 1
The sun gear S3 is fixed to a sleeve shaft 12 rotatably supported on the counter shaft 6 with the counter driven gear 17 meshing with the counter driven gear 17. And
The pinion P3 is supported by a carrier CR3 formed of a flange integrally connected to the counter shaft 6, and the carrier CR3 supporting the other end of the pinion P3 is connected to an inner hub of the UD direct clutch C3. The second simple planetary gear 11 has a sun gear S4 formed on the sleeve shaft 12 and is connected to the sun gear S3 of the first simple planetary gear. The ring gear R4 is connected to the counter shaft 6. .

The UD direct clutch C3 is
The sun gears S3 and S4 are interposed between the carrier CR3 of the first simple planetary gear and the connected sun gears S3 and S4, and the connected sun gears S3 and S4 are engaged by a fourth brake B4 including a band brake. Can stop. Further, the carrier CR4 supporting the pinion P4 of the second simple planetary gear can be locked by the fifth brake B5.

Next, the operation of the mechanism of the five-speed automatic transmission will be described with reference to FIGS.

First speed (1S) in the D (drive) range
In the T) state, the forward clutch C1 is engaged, and the fifth brake B5 and the second one-way clutch F2
And the ring gear R2 of the double pinion planetary gear and the carrier CR4 of the second simple planetary gear 11 are held in a stopped state. In this state, the rotation of the input shaft 3 is transmitted to the ring gear R1 of the simple planetary gear via the forward clutch C1, and the ring gear R2 of the double pinion planetary gear is in a stopped state, so that the two sun gears S1 and S2 idle in the opposite direction. While doing so, the common carrier CR is largely decelerated and rotated in the forward direction. That is, the main transmission mechanism 2 is in the first speed state, and the reduced rotation is transmitted to the ring gear R3 of the first simple planetary gear in the auxiliary transmission mechanism 5 via the counter gears 18 and 17. The auxiliary transmission mechanism 5 is in the first speed state with the carrier CR4 of the second simple planetary gear stopped by the fifth brake B5, and the reduced speed rotation of the main transmission mechanism 2 is further reduced by the auxiliary transmission mechanism 5. Output from the output gear 16.

In the second speed (2ND) state, in addition to the forward clutch C1, the second brake B2 (and the first brake B1) operates, and further, the second one-way clutch F2 to the first one-way clutch F1 , And the fifth brake B5 is maintained in the locked state. In this state, the sun gear S2 is set to the second brake B
2 and the first one-way clutch F1 is stopped,
Therefore, the rotation of the ring gear R1 of the simple planetary gear transmitted from the input shaft 3 via the forward clutch C1 corresponds to the rotation of the ring gear R2 of the double pinion planetary gear.
The carrier CR is decelerated in the forward direction while idling in the forward direction. Further, the decelerated rotation is performed by the counter gears 18 and 1.
The transmission is transmitted to the auxiliary transmission mechanism 5 via the transmission 7. That is, the main speed change mechanism 2 is in the second speed state, and the auxiliary speed change mechanism 5 is in the first speed state by engagement of the fifth brake B5.
By combining the speed states, the second speed can be obtained in the entire automatic transmission 1. Note that, at this time, the first brake B1 is also in the operating state, but when the second speed is established due to the coast down, the first brake B1 is released.

In the third speed (3RD) state, the forward clutch C1, the second brake B2, the first one-way clutch F1 and the first brake B1 are kept in the engaged state, and the fifth brake B5 is locked. Is released and the fourth brake B4 is engaged. That is, the main transmission mechanism 2 is kept in the same state, the above-mentioned rotation at the second speed is transmitted to the sub transmission mechanism 5 via the counter gears 18 and 17, and the sub transmission mechanism 5 performs the first simple transmission. The rotation of the planetary gear from the ring gear R3 is output from the carrier CR3 as a second-speed rotation by fixing the sun gear S3 and the sun gear S4, so that the automatic transmission 1 as a whole is driven at the second speed of the main transmission mechanism 2 and the second speed of the auxiliary transmission mechanism 5. The third speed is obtained.

In the fourth speed (4TH) state, the main transmission mechanism 2
Are the forward clutch C1, the second brake B2, the first one-way clutch F1, and the first brake B
This is the same as the above-described second speed and third speed states in which the first gear 1 is engaged, and the auxiliary transmission mechanism 5 releases the fourth brake B4 and performs UD
The direct clutch C3 is engaged. In this state, the carrier CR3 of the first simple planetary gear is connected to the sun gears S3 and S4, and the planetary gears 10 and 11 are directly connected to rotate. Therefore, the second speed of the main transmission mechanism 2 and the direct connection (third speed) of the auxiliary transmission mechanism 5 are combined, and the fourth speed rotation is output from the output gear 16 in the entire automatic transmission.

In the fifth speed (5TH) state, the forward clutch C1 and the direct clutch C2 are engaged, and the rotation of the input shaft 3 rotates the ring gear R1 of the simple planetary gear.
And transmitted to the sun gear S1, the main transmission mechanism 2
Direct connection rotation in which the gear unit rotates integrally. On this occasion,
The first brake B1 is released and the second brake B2
Is held in the engaged state, but the first one-way clutch F
When the wheel 1 idles, the sun gear S2 idles. Further, the auxiliary transmission mechanism 5 is a directly connected rotation in which the UD direct clutch C3 is engaged.
The speed (direct connection) and the third speed (direct connection) of the auxiliary transmission mechanism 5 are combined, and the fifth speed rotation is output from the output gear 16 in the entire automatic transmission.

Further, the automatic transmission has an intermediate shift stage that operates during a downshift such as acceleration, that is, a third-speed low and a fourth-speed low.

In the low speed state of the third speed, the forward clutch C1
And the direct clutch C2 is connected (the second brake B
2 is in the engaged state, but overruns due to the one-way clutch F1), and the main transmission mechanism 2 is in the third speed state in which the planetary gear unit 15 is directly connected. On the other hand, the fifth brake B5 is locked, and the auxiliary transmission mechanism 5 is in the first speed state. Therefore, the third speed state of the main transmission mechanism 2 and the first speed state of the auxiliary transmission mechanism 5 are combined, and the automatic transmission 1 As a whole, a gear stage having a gear ratio between the second and third speeds described above is obtained.

In the low speed state of the fourth speed, the forward clutch C1
And the direct clutch C2 is connected to the main transmission mechanism 2
Is in the third speed (direct connection) state as in the third speed low state. On the other hand, when the fourth brake B4 is engaged, the sun gear S of the first simple planetary gear 10
Sun gear S of third and second simple planetary gears 11
4 is fixed and in the second speed state. Therefore, the main transmission mechanism 2
The third speed state and the second speed state of the auxiliary transmission mechanism 5 are combined to obtain the above-mentioned gear ratio in the automatic transmission 1 as a whole between the third and fourth speeds.

In FIG. 3, the dotted circles indicate the operating state (4, 3, or 2 ranges) of the engine brake during coasting. That is, at the first speed, the third brake B3 operates to prevent the rotation of the ring gear R2 due to the overrun of the second one-way clutch F2. In the second gear, the third gear, and the fourth gear, the first brake B1 is actuated and the sun gear S1 due to the overrun of the first one-way clutch F1.
Block the rotation of

In the R (reverse) range,
The direct clutch C2 and the third brake B3 are engaged, and the fifth brake B5 is engaged. In this state, the rotation of the input shaft 3 is transmitted to the sun gear S1 via the direct clutch C2, and the ring gear R2 of the double pinion planetary gear is stopped by the third brake B3. The carrier CR also reverses while idling, and the reverse rotation is transmitted to the auxiliary transmission mechanism 5 via the counter gears 18 and 17. In the auxiliary transmission mechanism 5, the carrier CR4 of the second simple planetary gear is also stopped in the reverse rotation direction based on the fifth brake B5, and the first speed state is maintained. Therefore, the reverse rotation of the main transmission mechanism 2 and the
The high speed rotation is combined, and the output shaft 16 outputs the reverse rotation deceleration rotation.

FIG. 1 is a block diagram showing an electric control system. Reference numeral 21 denotes a control unit (ECU) comprising a microcomputer (microcomputer), an engine rotation sensor 22, and a throttle opening for detecting an accelerator pedal depression amount of a driver. Degree sensor 23, sensor 2 for detecting the input shaft rotation speed (= turbine rotation speed) of the transmission (automatic transmission mechanism)
5. Each signal is input from a vehicle speed (= automatic transmission output shaft rotation speed) sensor 26 and a shift sensor 27 for detecting a manual shift operation, and is output to the linear solenoid valves SLS and SLU of the hydraulic circuit. . The control unit 21 includes a release-side control unit 21a that controls a release-side hydraulic pressure.
, An engagement-side control unit 21b that controls the engagement-side hydraulic pressure, and an off-up control unit 21c that performs control related to off-up shift inhibition.

FIG. 4 is a diagram schematically showing a hydraulic circuit.
A plurality of frictional engagement elements (clutches and And a plurality of hydraulic servos 29 and 30 for connecting and disconnecting brakes. The input pressures a1 and a2 of the linear solenoid valves SLS and SLU are supplied with solenoid modulator pressure, and the control oil pressure from the output ports b1 and b2 of the linear solenoid valves is used to control the pressure control valves 31 and 32, respectively. The oil is supplied to the oil chambers 31a and 32a. The pressure control valves 31 and 32 supply line pressures to the input ports 31b and 32b, respectively. The pressure control oil pressures from the output ports 31c and 32c adjusted by the control oil pressure are applied to shift valves 33 and 35, respectively. Are supplied to the respective hydraulic servos 29 and 30 as appropriate.

This hydraulic circuit shows the basic concept relating to a so-called clutch-to-clutch shift in which one frictional engagement element is released and the other frictional engagement element is engaged. 29 and 30 and the shift valves 33 and 35 are symbolically shown. Actually, many hydraulic servos are provided corresponding to the automatic transmission mechanism. The hydraulic servo for the fourth brake B4, the hydraulic servo for the fifth brake B5, and the hydraulic servo for the third clutch C3 and the hydraulic servo for the fourth brake B4 during the 4 → 3 shift. There are also many shift valves that switch the hydraulic pressure to As shown in the hydraulic servo 30, the hydraulic servo has a piston 39 which is fitted in a cylinder 36 in an oil-tight manner by an oil seal 37, and the piston 39 is connected to a pressure control valve 32 acting on a hydraulic chamber 40. Moves against the return spring 41 based on the pressure-adjusted oil pressure from the outer friction plate 42 and the inner friction material 43. Although the friction plate and the friction material are shown by the clutch, it is needless to say that the friction plate and the friction material also correspond to the brake.

Now, as shown in a shift map MAP shown in FIG. 6, the driver changes the accelerator position from the vehicle state P1 of the vehicle speed and the throttle opening which is equal to or lower than the predicted stop speed SV and equal to or lower than the upshift point of 2-3 upshift. It is assumed that the throttle opening is returned by operating the pedal to bring the vehicle state to the vehicle speed and the throttle opening at the point P2.

The predicted stop speed SV is a low vehicle speed that is considered to be highly likely to stop the vehicle by operating the brake after the driver closes the accelerator below the vehicle speed. The vehicle speed is set in advance as a predicted stop speed SV. The vehicle speed is a value set by an experiment or the like.

The signal from the throttle opening sensor 23 indicates that the driver has released the accelerator pedal.
Is determined, the off-up control unit 21c is
Is commanded to perform control relating to the subsequent off-up shift based on the off-up shift control program PRO shown in FIG.

That is, in step S1 of the off-up shift control program PRO, the off-up control section 21c determines the current throttle opening th and the output shaft rotation speed of the transmission, ie,
The vehicle speed No is determined by the throttle opening sensor 23 and the vehicle speed sensor 2.
6 and in step S11, the throttle opening th
Then, it is determined whether the vehicle state determined from the vehicle speed No has crossed the 2-3 upshift line in the shift map MAP in FIG. If the vehicle has crossed, the timer is started in steps S12 and S13,
In step S14, it is confirmed that the state of crossing the 2-3 upshift line has been continued for a predetermined time, and the process proceeds to step S2.

As shown in FIG. 6, in the shift map MAP, for a region equal to or lower than the predicted stop speed SV and equal to or higher than the 2-3 upshift point, a predetermined throttle opening degree thguard is set as an upper limit threshold value, and the acceleration return is performed. An off-up shift prohibited area OUPR (shaded area in the figure) for prohibiting a -3 off-up shift is set. When the driver returns the accelerator pedal and the vehicle state enters the off-up shift prohibited area OUPR, the shift map MA
Upshifting based on P is prohibited and the state in which the low-speed gear in the vehicle state P1 is selected is maintained, so that off-up shifting and subsequent coast-down shifting are not performed, thereby generating shift shock and rattling noise. To prevent.

In the shift map MAP, as shown in FIG. 6, the throttle opening th guard at the time of entering the off-up shift prohibited area OUPR is set as an upper limit threshold of the inhibition. The throttle opening th guard hi at the time of exiting from OUPR is set as a threshold for canceling prohibition. The prohibition threshold th guard is set slightly lower than the prohibition release threshold th guard hi,
When the vehicle state enters the off-up shift prohibition region OUPR, chattering in which the prohibition of the off-up shift state and the release of the prohibition are repeatedly prevented by a slight change in the throttle opening th is prevented.

As described above, the driver determines that the speed is less than or equal to the predicted stop speed SV in the shift map MAP shown in FIG.
The throttle opening is returned by operating the accelerator pedal from the vehicle state P1 of the vehicle speed and the throttle opening below the -3 shift point, and when the vehicle state passes the 2-3 upshift point in step S11, the ECU 21 increases. A shift command is issued based on the shift map MAP. At this time, the off-up control section 21c enters step S2 of the off-up shift control program PRO, and the current throttle opening th
Is smaller than the prohibition threshold th gurd and the current vehicle speed No
However, the vehicle speed is equal to or lower than the predicted stop speed SV at which the driver is likely to stop the vehicle, that is, the off-up shift prohibition region O
It is determined whether the output speed is equal to or less than a threshold value output CD at the vehicle speed of UPR.

The current throttle opening th is prohibited threshold th g
urd and the vehicle speed No at which the current vehicle speed No is equal to or less than the predicted stop speed SV, that is, the off-up shift prohibition region OUP
When the vehicle speed is equal to or lower than the threshold value output CD at the vehicle speed of R, it is determined that the vehicle state is within the 2-3 off-up shift prohibited area OUPR as shown by a point P2 in FIG. It is predicted that the intention to stop the vehicle by operating the brake after the operation, that is, the intention to stop the vehicle is large, and then, in step S22, the operation for prohibiting the off-up shift is started.

In step S2, the current throttle opening th is greater than a prohibition threshold th gurd, or the current vehicle speed (output shaft rotation speed) No is equal to or higher than the predicted stop speed SV, ie, an off-up shift prohibition region. Threshold output at vehicle speed
In the case of the CD or more, the vehicle state is outside the off-up shift prohibition area OUPR, and the driver predicts that the intention to stop the vehicle, that is, the intention to stop, is small. Then, it is determined that the throttle return operation does not correspond to the off-up shift prohibition operation, and the process proceeds to step S4 to perform a normal upshift operation without taking the upshift prohibition operation.

If it is determined in step S2 that the vehicle state is within the 2-3 off-up shift prohibited area OUPR, the process proceeds to step S22, as described above, in which the upshift is prohibited. The shift is prohibited.

Next, at step S3, the throttle opening th exceeds the prohibition release threshold th gurd hi, and furthermore, the actual input torque Tin from the engine to the automatic transmission.
However, the off-up shift prohibition operation is continued until the torque exceeds the predetermined 2-3 upshift prohibition release threshold value inT guard, so that the upshift operation is not performed.

In step S2, even if the driver performs the closing operation of the accelerator and the throttle opening decreases first, and the upshift is prohibited in step S22, the input torque Tin of the engine is maintained at the throttle opening. This will be delayed with respect to the th movement. Therefore, step S
In step 3, if the upshift prohibition release condition is a condition that the input torque exceeds the threshold value inT guard, the input torque that has not yet decreased is larger than the threshold value inT guard. There is a danger that chattering will occur due to cancellation.

Therefore, in step S3, as an upshift prohibition release condition, the actual input torque Tin from the engine to the automatic transmission exceeds a predetermined threshold value inTguard at the torque at which the 2-3 upshift prohibition is released. In addition, the throttle opening th becomes the prohibition threshold th gurd
A to exceed the larger ban threshold th gurd hi
Under the ND condition, a malfunction caused by a delay in the output torque Tin due to the closing operation of the accelerator by the driver is prevented. Such control is extremely effective in preventing a malfunction when the condition of step S2, which is a condition for prohibiting the off-up shift, and the condition of step S3 for canceling the off-up shift prohibition state are different. Technology.

Further, once the off-up shift is prohibited, the throttle opening th exceeds the prohibition release threshold th gurd hi unless the driver subsequently depresses any throttle in step S3, and the engine is stopped. Since the actual input torque Tin to the automatic transmission from the engine does not exceed the threshold value inT guard at the torque at which the predetermined 2-3 upshift prohibition is released, the off-up shift control program PRO may proceed from step S3. In other words, even if the driver subsequently performs a brake operation to stop the vehicle, the prohibited state of the 2-3 off-up shift is maintained, so that the second speed is maintained. Therefore, unnecessary 3-2 coast down shift control based on the shift map MAP is not performed, and the occurrence of shock and rattling can be prevented. Thereafter, when the vehicle speed further decreases and crosses the 2-1 coast down point, coast down shift control to the first speed is performed.

The off-up transmission control program PRO is as follows:
In the off-up shift prohibited state, step S is always executed.
Step 3 is repeated and the driver monitors the throttle again.

When the driver depresses the accelerator pedal again when the driver feels the necessity of some torque from the off-up shift prohibited state, the throttle opening th increases. Then, the vehicle state reaches the point P3 shown in FIG. 6 after a predetermined time, and the throttle opening th becomes the threshold value th gur for prohibition release.
The actual input torque Tin from the engine to the automatic transmission exceeds the threshold value inT guard at the torque at which the predetermined 2-3 upshift prohibition is released. At this point, the off-up shift control program PRO enters the step S4 from the step S3, releases the prohibited state of the upshift, and executes the upshift command.

At this time, the upshift operation of the vehicle is delayed until the input torque Tin from the engine exceeds a predetermined threshold value inTguard at the torque at which the 2-3 upshift prohibition is released. The required torque can be applied to the vehicle, and the upshift operation started simultaneously with the depression of the throttle prevents the driver from feeling uncomfortable.

Although the above-described embodiment has been described with respect to the 2-3 off-up shift, the present invention is not limited to the 2-3 off-up shift, and can be applied to any shift stage as long as the off-up shift is performed. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of an electric control circuit of an automatic transmission to which the present invention is applied.

FIG. 2 is a skeleton diagram showing a mechanism portion of an automatic transmission to which the present invention can be applied.

FIG. 3 is a view showing the operation of each friction engagement element.

FIG. 4 is a diagram schematically illustrating a hydraulic circuit related to a shift based on gripping of a friction engagement element (clutch-to-clutch).

FIG. 5 is a flowchart showing an off-up shift control program.

FIG. 6 is a diagram illustrating an example of a shift map near an off-up shift prohibition region.

[Explanation of symbols]

13 engine output shafts 14a, 14b output shaft 21 shift control means (ECU) 21c stop intention predicting means, shift prohibiting means (off-up control unit) SLU, SLS shift control means (linear solenoid Valve) C1 to C3: Friction engagement element (clutch) B1 to B5: Friction engagement element (brake)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F16H 63:12 F16H 63:12 (72) Inventor Seiwa Nomura 10 Takane Fujiimachi, Anjo-shi, Aichi Aisin Ai F-term (reference) in W3U Corporation 3J552 MA02 MA12 NA01 NB01 PA19 PA33 RB08 RB18 RC12 SA02 SB13 TA06 TB01 TB11 VA32Y VA37Y VA77Y VB01W VC01W VC03W

Claims (5)

[Claims] An input shaft to which power from an engine output shaft is input, an output shaft connected to wheels, and a plurality of friction engagement elements for changing a power transmission path between the input shaft and the output shaft. And a shift control means for performing a shift operation by appropriately controlling the plurality of frictional engagement elements, and a shift of an automatic transmission that performs an upshift to a predetermined shift speed by closing an accelerator by a driver. In the control device, there is provided stop intention predicting means for predicting whether or not the accelerator closing operation is due to an intention to stop the vehicle by stepping on a brake thereafter. The shift control of the automatic transmission, which is provided with a shift prohibiting means for prohibiting an upshift to the predetermined shift speed when it is predicted that the shift is intended to stop. Location. 2. The stop intention predicting means predicts that there is a stop intention when the output shaft rotation speed of the transmission after the accelerator closing operation is equal to or less than a predetermined value. A shift control device for an automatic transmission according to claim 1. 3. The stop intention predicting means predicts that there is a stop intention when the throttle opening after the accelerator closing operation is equal to or less than a predetermined value.
The shift control device for an automatic transmission according to claim 1. 4. The gear shift prohibiting means maintains the gear shift operation prohibition until the input torque from the engine exceeds a predetermined value when the accelerator is depressed. A shift control device for an automatic transmission according to claim 1. 5. The shift prohibition control means, when the accelerator is depressed, until the input torque from the engine exceeds a predetermined value and the throttle opening exceeds a predetermined value. The shift control device for an automatic transmission according to claim 4, wherein prohibition is maintained.