JPH05263912A - Speed change control method for automatic transmission - Google Patents

Abstract

PURPOSE:To reduce a shock at the time of speed change in an automatic transmission in which a shift up operation is performed by reducing an input shaft rotation speed so that the rate of change therein may be equal to a target rotation speed change rate after setting of an initial duty factor of a solenoid valve for operating a hydraulic clutch. CONSTITUTION:After (Ni)' is read in step S60, a rotation speed change rate (Nt)' at a starting time point for speed change and a change rate (Nt)'' in this rotation speed change rate are determined (S61). Then, an initial duty factor Da is corrected (S64, S65, S68, S69) on the basis of the (Nt)' and (Nt)'' (S62, S63, S66, S67).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control method for an automatic transmission.

[0002]

2. Description of the Related Art An automatic transmission mounted on an automobile is equipped with a large number of friction engagement means such as hydraulic multi-plate clutches and hydraulic brakes, and the operating oil pressure supplied to these friction engagement means is adjusted. A duty solenoid valve whose duty ratio is controlled by a controller is widely used as a means for doing so.

This duty solenoid valve (hereinafter, simply referred to as a solenoid valve) can adjust the working oil pressure to a pressure value corresponding to the duty ratio by changing the duty ratio. It controls the engagement and release of the brake. The shift change of the automatic transmission is performed by switching an operating clutch or brake, that is, by disengaging one friction engagement means while engaging another friction engagement means.

For example, when shifting up the automatic transmission from the second speed to the third speed, the clutch for establishing the second speed (hereinafter referred to as the disengagement side clutch) is released and the third speed is set. The clutch (hereinafter referred to as the coupling side clutch) that establishes the engagement is engaged, and a so-called grip change operation of the clutch is performed. As a result, the transmission path of the engine torque is switched, and the shift speed is switched.

By the way, when the automatic transmission shifts up, it is necessary to reduce the input shaft rotation speed of the transmission. Therefore, in the clutch re-gripping operation at the time of upshifting, first, after the disengagement of the disengagement side clutch is started, the rotation speed Nt of the automatic transmission input shaft is changed by the gear ratio (Nt) ′ of the target rotation speed The torque transmission amount of the coupling side clutch is feedback-controlled so as to be equal to the ratio (Ni) ', and is reduced to the synchronous rotation speed. It should be noted that the symbol (Nt) ′ represents a time differential value of the rotation speed Nt, and other time differential values are similarly expressed below.

This point will be described in detail. As mentioned above,
The rate of change of the rotation speed Nt of the input shaft can be changed by increasing or decreasing the torque transmission amount of the coupling side clutch. In order to favorably perform the upshift, it is required that the rotational speed Nt be rapidly reduced to the synchronous rotational speed, and that the change in the input shaft rotational speed near the synchronous rotational speed be minimized. In order to satisfy these contradictory requirements, it is desirable to reduce the input shaft rotation speed Nt at the optimum target rotation speed change rate (Ni) ′.

The controller first drives the solenoid valve on the coupling side at a duty ratio of 100% to move the engagement side clutch from a position where the engagement is completely released to a position immediately before starting the engagement. After performing the so-called backlashing operation, the solenoid valve is driven at a predetermined duty ratio Da. Here, for the duty ratio Da, the input shaft rotational speed change rate (Nt) 'is calculated as the target rotational speed change rate (Ni)'.
It is set as an initial duty ratio for feedback control.

[0008]

By the way, when the initial duty ratio Da is larger than the optimum value, the operating oil pressure supplied to the engagement side clutch is too high, and the rotation speed change rate at the start of the feedback control ( Nt) 'has a larger absolute value than the target rotation speed change rate (Ni)', which causes hunting, an increase in shift shock, and the like.

When the initial duty ratio Da is smaller than the optimum value, the operating oil pressure supplied to the engagement side clutch is low and the rotation speed change rate (Nt) 'is the target rotation speed change rate (Ni)'. The absolute value will be smaller than that, and the completion of the upshift will be delayed. Conventionally, the initial duty ratio Da is set to a constant value that is different for each shift pattern, and this value is merely changed by so-called learning control. However, the vehicle operating conditions and the driver's accelerator operation etc. when the shift-up is carried out differ for each shift-up, and therefore the optimum initial duty to be set for each shift-up is carried out. Rate D
a changes. Therefore, there is a problem that it is difficult to set the initial duty ratio Da to an optimum value for each shift operation.

The present invention has been made to solve the above-mentioned problems, and provides a shift control method for an automatic transmission capable of correcting the initial duty ratio to an optimum value when performing the feedback control. The purpose is to do.

[0011]

In order to achieve the above object, according to the present invention, the operating oil pressure of the friction engagement means for switching the shift speed is adjusted by the duty ratio controlled oil supply / discharge oil means. When shifting up the automatic transmission from the low speed stage to the high speed stage, after setting the initial duty ratio of the oil supply / drainage means to a predetermined value, the rate of change of the rotational speed of the input shaft is feedback-controlled to the target rate of change. In a shift control method for an automatic transmission that reduces the rotation speed of an input shaft toward a high speed synchronous rotation speed, a change rate of the rotation speed of the input shaft at the start of a shift and a further change rate of this change rate are The initial duty ratio is detected and corrected based on these values.

[0012]

According to the method of the present invention, the initial duty ratio is corrected on the basis of the rate of change of the rotational speed of the input shaft at the start of gear shifting and the rate of further change of this rate of change. The initial duty ratio is set to a value suitable for controlling the rate of change of the rotation speed of the input shaft at the start of the feedback control to be close to the target rate of change.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of an automatic transmission of an automobile that implements a hydraulic control method according to the present invention. Reference numeral 1 in the figure indicates an internal combustion engine, and the output of the engine 1 is transmitted to drive wheels (not shown) via an automatic transmission 2.

The automatic transmission 2 comprises a torque converter 4, a gear transmission 3, a hydraulic circuit 5 and a controller 40. The gear transmission 3 includes, for example, a gear train with four forward gears and one reverse gear, and a number of gear shift friction engagement means for performing gear shift operations by switching the gear ratio of the gear train. The shift friction engagement means is, for example, a hydraulic clutch or a hydraulic brake.

FIG. 2 is a partial block diagram of the gear transmission 3. A first drive gear 31 and a second drive gear 32 are rotatably arranged around the input shaft 3a. In addition, the input shaft 3a between the first drive gear 31 and the second drive gear 32,
Hydraulic clutches 33 and 34 are fixedly provided as gear shift friction engagement means. The drive gears 31 and 32 rotate integrally with the input shaft 3a by engaging the clutches 33 and 34, respectively.

The intermediate transmission shaft 35 arranged parallel to the input shaft 3a is connected to the drive axle via a final reduction gear unit (not shown). A first driven gear 36 and a second driven gear 37 are fixedly mounted on the intermediate transmission shaft 35, and these driven gears 36 and 37 mesh with the drive gears 31 and 32, respectively. Therefore, when the clutch 33 and the first drive gear 31 are engaged,
The rotation of the input shaft 3a depends on the clutch 33, the first drive gear 3
1, transmitted to the first driven gear 36, the intermediate transmission shaft 35,
For example, the second speed is established. Also, the clutch 34 and the second
When the drive gear 32 is engaged, the rotation of the input shaft 3a is transmitted to the clutch 34, the second drive gear 32, the second driven gear 37, and the intermediate transmission shaft 35 to establish, for example, the third speed. To be done.

From the state in which the clutch 33 on the second speed side is engaged, the clutch 33 is disengaged while the third gear is engaged.
By engaging the clutch 34 on the high speed side, the automatic transmission 2
Shifts up from second gear to third gear. Conversely, by engaging the clutch 33 while releasing the engagement of the clutch 34 from the state in which the clutch 34 is engaged,
The automatic transmission 2 shifts down from the third speed to the second speed.

The clutches 33 and 34 are hydraulic multi-plate clutches. FIG. 3 shows a cross section of the clutch 34, which has a number of friction engagement plates 50 arranged in hydraulic fluid. When hydraulic oil is supplied from the oil passage 14 into the clutch 34 through the port 51, the piston 52 moves forward to frictionally engage the friction engagement plates 50. On the other hand, when the piston 52 returns while being pressed by the return spring 53 and discharging the hydraulic oil into the oil passage 16 through the port 51, the friction engagement between the friction engagement plates 50 is released. The clutch 3
3 is also configured similarly to this clutch 34.

The hydraulic circuit 5 has a duty solenoid valve (hereinafter simply referred to as a solenoid valve) corresponding to each of the above-mentioned speed change friction engagement means, and each speed change friction engagement means, that is, each clutch. And the brakes are operated independently of each other. Since each solenoid valve operates each clutch and brake in the same manner, the solenoid valve that operates the clutch 34 will be described with reference to FIG. 4, and description of the other solenoid valves will be omitted.

FIG. 4 shows a part of the hydraulic circuit 5, which includes a solenoid valve 11 capable of supplying hydraulic pressure to the hydraulic clutch 34. The solenoid valve 11 is a normally closed two-position switching valve, and has ports 11a to 11c at three locations. A first oil passage 13 extending to an oil pump (not shown) is connected to the first port 11a. A pressure adjusting valve (not shown) or the like is interposed in the middle of the first oil passage 13, and an operating hydraulic pressure (line pressure) adjusted to a predetermined pressure is supplied.

The second oil passage 14 extending to the hydraulic clutch 34 is connected to the second port 11b, and the third oil passage 15 extending to an oil tank (not shown) is connected to the third port 11c. These second and third oil passages 14,
Stops 16 and 17 are provided in the middle of 15, respectively. The flow passage area of the throttle 16 provided in the second oil passage 14 is set larger than the flow passage area of the throttle 17 provided in the third oil passage 15. Further, an accumulator 18 is connected in the middle of the second oil passage 14 between the clutch 34 and the throttle 16.

The solenoid valve 11 is electrically connected to the controller 40, and the controller 40 controls the duty ratio at a predetermined cycle, for example, a control cycle of 50 hertz. When the solenoid 11e of the solenoid valve 11 is deenergized, the valve body 11f is pressed by the return spring 11g and the first port 11a is pressed.
While shutting off the second port 11b and the solenoid 11e
When the valve is biased, the valve body 11f lifts against the spring force of the return spring 11g to connect the first port 11a and the second port 11b. The second port 11b and the third port 11c are always in communication.

The controller 40 includes a ROM (not shown),
It incorporates a storage device such as a RAM, a central processing unit, an input / output device, a counter, and the like. Various sensors, such as the Nt sensor 21, the No sensor 22, and the θt sensor 23, are electrically connected to the input side of the controller 40. The Nt sensor 21 is a turbine rotation speed sensor that detects the rotation speed Nt of the turbine of the torque converter 4 (that is, the input shaft of the automatic transmission 2). Also, the N
The o sensor 22 is a transfer drive gear rotation speed sensor that detects a rotation speed No of a transfer drive gear (not shown). The controller 40 can calculate the vehicle speed V based on this rotation speed No. The θt sensor 23 is a throttle valve opening sensor that detects a valve opening θt of a throttle valve arranged in the intake passage (not shown) of the engine 1. Each of these sensors 21 to 23 supplies a detection signal to the controller 40 at predetermined time intervals.

The controller 40 shifts the automatic transmission 2 according to a program stored in the storage device. That is, the controller 40 continues to monitor the signals from the Nt sensor 21, the No sensor 22, the θt sensor 23, and the like, and determines the shift speed suitable for the running state of the vehicle based on these signals. And, for example,
When recognizing the necessity of shifting up from the second speed to the third speed based on the vehicle speed V and the throttle valve opening θt, the controller 40 causes the disengagement side clutch 33 and the coupling side clutch 34.
Perform the grip change operation.

At this time, the controller 40 changes the rotation speed Nt detected by the Nt sensor 21 into the change rate (N
t) ′ is made equal to the target rotation speed change rate (Ni) ′, and is reduced, and shift up is performed. The target rotation speed change rate (Ni) 'is set for each shift-up mode and is stored in the storage device of the controller 40 in advance.

5 and 6 show the control procedure of the coupling side clutch 34 at the time of upshifting, and FIG.
Shows changes in the duty ratio of the solenoid valve 11 that operates the coupling side clutch 34. Step S8 in FIG.
At 0, the controller 40 drives the solenoid valve 11 at the duty ratio of 100% for the time Tf to perform the rattling operation of the coupling side clutch 34. This time Tf
Is the time obtained by experiments or the like and is stored in advance in the storage device of the controller 40. When the solenoid valve 11 is driven at the duty ratio of 100% for the time Tf, the loosening operation of the coupling side clutch 34 is completed.

Next, the controller 40 proceeds to step S8.
1, the solenoid valve 11 with the initial duty ratio Da
Drive is started, and step S82 is repeatedly executed and waits until the start of gear shift is detected. The controller 40 uses the rotation speed No supplied from the No sensor 22.
Then, the substantial start of the upshift is detected based on the rotation speed Nt. More specifically, the storage device of the controller 40 stores in advance the gear ratio at each shift stage of the automatic transmission 2. Then, the controller 40 obtains the product of the rotation speed No and the gear ratio at the second speed, and when the speed difference between the product and the rotation speed Nt reaches the predetermined value ΔNb, the shift up is started. to decide. The predetermined value ΔNb is stored in the storage device of the controller 40 in advance.

When the shift start is detected in step S82 (time Ts in FIG. 7), the controller 40 proceeds to step S83. In step S83, the controller 40 corrects the initial duty ratio Da based on the duty ratio correction amount ΔD (Da = Da).
+ ΔD). The controller 40 determines the duty ratio correction amount Δ
In order to obtain D, a duty ratio correction amount determination routine is executed.

FIG. 8 shows a flow chart of this duty ratio correction amount determination routine. First, in step S60,
The controller 40 controls the target rotation speed change rate (N
i) 'is read and the process proceeds to step S61. Then, in step S61, the controller 40 calculates a rotation speed change rate (Nt) 'which is a time differential value of the rotation speed Nt based on the rotation speed Nt detected last time and the rotation speed Nt detected this time, Furthermore, based on this calculation result,
Rate of change in rotational speed (Nt) 'according to previous calculation and rate of change in rotational speed that is a time derivative of rotational speed change rate (Nt)' to rotational speed change rate (Nt) 'according to current calculation. (Nt) ”is calculated.

Next, the controller 40 proceeds to step S6.
2 and S66, the rotational speed change rate (Nt) '
Discriminant value C₁(Ni) 'and C₂(Ni) 'to determine the magnitude relationship
It Here, the shift-up operation is the engine speed.
The target rotation speed change is
The conversion rate (Ni) 'is a negative value, and each predetermined value is C ₁
> 1.0> C₂Since it is set to> 0, the discriminant value
C₁(Ni) '<(Ni)' <discriminant value C₂(Ni) '.

The predetermined values C ₁ and C ₂ are stored in advance in the storage device of the controller 40. Therefore, when the rotation speed change rate (Nt) 'is equal to or smaller than the determination value C ₁ (Ni)', the rotation speed Nt is the target rotation speed change rate (Ni) '.
It is thought that it is beginning to decrease at a more rapid rate of change.
When the rotational speed change rate (Nt) 'is larger than the discriminant value C ₁ (Ni)' and smaller than the discriminant value C ₂ (Ni) ', the rotational speed Nt is the target rotational speed change rate. (Ni) '
It is considered that the rate of change is starting to decrease at a rate close to. Further, when the rotation speed change rate (Nt) 'is equal to or larger than the discriminant value C ₂ (Ni)', the rotation speed Nt is the target rotation speed change rate (Nt).
It is considered that the rate of change is beginning to decrease at a slower rate than i) '.

Therefore, as shown in FIG. 8, the controller 40 first determines in step S62 whether the rotational speed change rate (Nt) 'is less than or equal to the determination value C ₁ (Ni)'. Then, if this condition is satisfied, that is, if it is considered that the rotation speed Nt has started to decrease at a change rate that is more rapid than the target rotation speed change rate (Ni) ', the process proceeds to step S63.

In step S63, the controller 4
0 compares the change rate (Nt) "of the rotational speed change rate with the discriminant value A. The discriminant value A is a positive constant previously stored in the storage device of the controller 40. Change in the rotational speed change rate When the rate (Nt) "is equal to or smaller than the discriminant value A, it means that the rotational speed change rate (Nt) 'is decreasing in the direction away from the target rotational speed change rate (Ni)'. It is preferable to reduce Da so that the engagement of the coupling side clutch 34 is released a little and the decrease of the rotation speed Nt is suppressed a little.

Therefore, the controller 40 determines in step S
64, the duty ratio correction amount ΔD is set to D2 (<
0) is set. Further, in step S63 described above, when the change rate (Nt) ”of the rotation speed change rate is larger than the discriminant value A, the rotation speed Nt is a steeper change rate than the target rotation speed change rate (Ni) ′. However, it is considered that the change rate (Nt) 'is approaching the target rotational speed change rate (Ni)', so in such a case, the initial duty ratio Da is
Need not be corrected.

Therefore, the controller 40 proceeds from step S63 to step S65 as shown in FIG.
The duty ratio correction amount ΔD is set to 0. On the other hand, in step S62 described above, the rotation speed change rate (N
If t) ′ is larger than the discriminant value C ₁ (Ni) ′, the process proceeds to step S66. In step S66, the controller 44 determines that the rotation speed change rate (Nt) 'is the determination value C ₂ (N
i) 'It is determined whether or not it is greater than or equal to. Then, if this condition is satisfied, that is, if it is considered that the rotation speed Nt has started to decrease at a change rate gentler than the target rotation speed change rate (Ni) ', the process proceeds to step S67.

In step S67, the controller 4
0 compares the change rate (Nt) "of the rotational speed change rate with the determination value B. The determination value B is a negative constant previously stored in the storage device of the controller 40. Change of the rotational speed change rate When the rate (Nt) ”is equal to or smaller than the discriminant value B, it means that the rotational speed change rate (Nt) ′ is increasing in the direction away from the target rotational speed change rate (Ni) ′. It is preferable that the rate Da be increased, the engagement of the coupling side clutch 34 be slightly accelerated, and the rotation speed Nt be slightly reduced.

Therefore, the controller 40 determines in step S
68, the duty ratio correction amount ΔD is set to D1 (>
0) is set. Further, in step S67 described above, when the change rate (Nt) of the rotation speed change rate is smaller than the discriminant value B, the rotation speed Nt is a change rate gentler than the target rotation speed change rate (Ni) '. It is considered that the rate of change (Nt) ′ is starting to decrease, but it is considered that the rate of change (Nt) ′ is approaching the target rotational speed change rate (Ni) ′.
Therefore, in such a case, it is not necessary to correct the initial duty ratio Da.

Therefore, as shown in FIG. 8, the controller 40 proceeds from step S67 to step S65, and sets the duty ratio correction amount ΔD to 0. on the other hand,
In step S66 described above, the rotation speed change rate (N
t) ′ is smaller than the discriminant value C ₂ (Ni) ′, that is, when the rotation speed Nt is considered to start decreasing at a change rate close to the target rotation speed change rate (Ni) ′. ,
The controller 40 proceeds to step S65 and sets the duty ratio correction amount ΔD to 0.

As described above, the duty ratio correction amount Δ
When D is set, in step S69, the initial duty ratio Da is corrected by adding the duty ratio correction amount ΔD to the stored initial duty ratio Da.
Then, the controller 40 ends the routine,
It progresses to step S84 of FIG. In step S84, driving of the solenoid valve 11 is started. At this time, as described above, when ΔD is set to D1, the duty ratio is (Da + D1) as shown by the solid line in the figure, and when ΔD is set to D2, two points are shown in the figure. When ΔD is set to 0 with the duty ratio (Da + D2) as shown by the chain line, the solenoid valve 11 is driven with the duty ratio Da as shown by the one-dot chain line in the figure. As a result, the hydraulic pressure of the engagement side clutch 34 is adjusted, and the rotational speed change rate (Nt) 'can be brought closer to the target rotational speed change rate (Ni)' quickly.

Then, the controller 40 proceeds to step S85 in FIG. 6 so that the rotational speed change rate (Nt) 'is larger than the discriminant value C ₁ (Ni)' and is larger than the discriminant value C ₂ (Ni) '. Judge whether the value has become small. When this condition is satisfied, that is, the rotational speed change rate (Nt) '
Is a value sufficiently close to the target rotation speed change rate (Ni) ′, the process proceeds to step S87 without executing step S86.

On the other hand, in step S85, the rotational speed change rate (Nt) 'is the discriminant value C ₁ (Ni)' and the discriminant value C ₂ (Ni) 'with respect to the target rotational speed change rate (Ni)'. If it is not within the specified range, the process proceeds to step S86. In step S86, the controller 40 determines whether or not the elapsed time from the time Ts at which the shift start is detected reaches a predetermined time. If the predetermined time has not been reached, the process returns to step S85 and step S85.
Steps S85 and S86 are repeatedly executed until either one of the conditions 85 and 86 is satisfied.

Therefore, while the controller 40 executes steps S84 to S86, that is, Ts in FIG.
From time T1 to time T1, the controller 40 continues to drive the solenoid valve 11 with the corrected duty ratio Da. In addition, between the time Ts and the time T1 in the figure, the controller 40 may increase the corrected initial duty ratio Da at a predetermined ratio when ΔD is set to D1. , ΔD is D
If set to 2, the corrected initial duty ratio D
You may make it reduce a at a predetermined ratio.

The controller 40 then proceeds to step S
From the time point when the operation proceeds to 87 (time point T1 in FIG. 7), feedback control is started so that the rotation speed change rate (Nt) ′ becomes the target rotation speed change rate (Ni) ′. Next, in Step S88, the controller 4
0 determines whether the rotations of the input shaft and the output shaft of the automatic transmission 2 are synchronized. If this synchronization has not ended, step S88 is repeatedly executed, and the above feedback control is repeatedly executed until the synchronization is achieved.
Whether or not the input shaft rotation speeds are synchronized is determined by, for example, obtaining the product of the rotation speed No and the gear ratio at the third speed, and when the speed difference between this product and the rotation speed Nt is a predetermined value ΔNf or less. Alternatively, it may be determined that the input axis and the output axis are synchronized. The predetermined value ΔNf is determined by the controller 40
Is previously stored in the storage device.

Then, in step S88, when the controller 40 detects the synchronization (time Te in FIG. 7), the process exits step S88 and proceeds to step S89. In step S89, the controller 40 drives the solenoid valve 11 at a duty ratio of 100%, and thereafter holds the engagement side clutch 34 in a completely engaged state. At this time, the release side clutch 33 is also completely released,
Upshift from the 2nd speed to the 3rd speed of the automatic transmission 2
finish.

In this embodiment, the automatic transmission 2
Has described the case of shifting up from the second speed to the third speed. However, other modes of shifting up, for example, shifting up from the first speed to the second speed or shifting from the third speed to the fourth speed. It goes without saying that the same method is also applied to the case of uploading.

[0046]

As described above, according to the method of the present invention, the rotational speed of the input shaft is controlled to the synchronous rotational speed on the high speed stage side while feedback controlling the rate of change of the rotational speed of the input shaft to the target change rate. When decreasing toward the input side, the initial duty ratio for starting the feedback control is corrected based on the rate of change of the rotation speed of the input shaft at the start of gear shift and the rate of further change of the input speed. The rate of change of the rotation speed of the shaft can be promptly converged to the target rate of change of rotation speed suitable for shifting. As a result, there is an excellent effect that the shift timing can be optimized and the shift shock can be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automatic transmission for an automobile in which a method according to the present invention is implemented.

FIG. 2 is a schematic configuration diagram showing a part of a gear train in the gear transmission of FIG.

FIG. 3 is a cross-sectional view showing the hydraulic clutch of FIG.

FIG. 4 is a schematic configuration diagram showing a part of a hydraulic circuit for operating the hydraulic clutches of FIGS. 2 and 3.

5 is a part of a flowchart showing an operation procedure of a coupling side clutch at the time of upshift, which is executed by the controller shown in FIGS. 1 and 4. FIG.

6 is a flow chart of the remainder following the flow chart of FIG.

FIG. 7 is a diagram showing a change state of a duty ratio of a coupling side solenoid valve at the time of upshifting.

FIG. 8 is a flowchart showing a procedure for setting a duty ratio correction amount of the coupling side solenoid valve at the time of upshifting, which is executed by the controller shown in FIGS. 1 and 4.

[Explanation of symbols]

 1 Engine 2 Automatic Transmission 3 Gear Transmission 5 Hydraulic Circuit 11 Solenoid Valves 13-15 Oil Path 34 Hydraulic Clutch 40 Controller

Claims (1)

[Claims] 1. When the automatic transmission shifts up from a low speed stage to a high speed stage by adjusting the hydraulic pressure of a friction engagement means for switching the shift speed by means of a duty ratio controlled supply / discharge oil means, After the initial duty ratio of the oil means is set to a predetermined value, the input shaft rotation speed is reduced toward the high-speed synchronous rotation speed while performing feedback control of the input shaft rotation speed change rate to the target change rate. In a transmission gear shift control method, detecting a rate of change of the rotational speed of the input shaft at the start of gear shift and a rate of further change of the rate of change, and correcting the initial duty rate based on these values. A method for controlling a shift of an automatic transmission characterized by: