JP2973256B2 - Anti-creep control system for automatic transmission for vehicles - Google Patents

Abstract

PURPOSE:To cause a creep-preventive control apparatus to have a function to make fail-safe in the case where there is a probability that back-movement may occur, during a creep-preventive control operation. CONSTITUTION:In a creep-preventive control apparatus adapted to prevent creep phenomenon by disconnection of a forward clutch when specified conditions are established, decision is made on whether or not a speed change stage where a brake for Hill holding is engaged can be achieved (steps 501 to 507). If the decisions that such achievement is impossible are sequentially made a specified number of times (steps 509 and 510), a flag F1 of 'fail' is caused to stand (step 511) to interrupt disconnection of the forward clutch.

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 preventing creep of an automatic transmission for a vehicle, and more particularly to a control device for a vehicle when a predetermined condition is satisfied even when a shift range is set to a forward drive range. By releasing the forward clutch (clutch engaged to achieve forward running) (including substantial release by reducing the hydraulic pressure), a neutral state is formed to prevent the occurrence of creep, and at the same time, a predetermined gear position is established. The present invention relates to a creep prevention control device for an automatic transmission for a vehicle, which achieves the above-described operation to prevent the vehicle from moving backward by a brake that forms the predetermined gear position.

[0002]

2. Description of the Related Art Conventionally, in an automatic transmission for a vehicle, if the shift range is set to a forward traveling range such as a drive range (D range), even if the vehicle speed is substantially zero, The gear transmission of the automatic transmission does not enter the neutral state, but is set to the first speed (or the second speed). Therefore, the output of the internal combustion engine is always transmitted to the output shaft via the torque converter and the forward clutch of the gear transmission, so that so-called creep occurs. As a result, the brake pedal is depressed to keep the vehicle stopped. Needed to be maintained. In addition, dragging of the torque converter at this time deteriorates the fuel consumption efficiency, and further causes a problem that the temperature of the hydraulic oil of the torque converter rises.

In view of the above, a control valve for controlling the hydraulic pressure of the forward clutch is newly provided, and when the accelerator pedal is released and the vehicle is substantially stopped, the shift range is set to the drive range. Even when the vehicle is in the forward travel range, the forward clutch is released or depressurized through the control valve, automatically forming a neutral state to prevent the occurrence of creep and improve fuel consumption efficiency. In addition, a technology that suppresses the temperature rise of the hydraulic oil of the torque converter (hereinafter, this control is referred to as “creep reduction control” in a narrow sense or “neutral control”).
(For example, JP-A-63-1064).
No. 49).

At the same time, in order to prevent the vehicle from moving backward on a slope or the like, there is a technique for performing a so-called "hill hold control" in which a brake capable of preventing the vehicle from moving backward is engaged. Known (Japanese Unexamined Patent Publication No.
-244856).

[0005] In this case, normally, a brake for forming an engine brake of a second speed (for example, two ranges (= S range)) is used as a hill hold brake to achieve the second speed. Thus, the hill hold control is executed.

[0006]

However, in the conventional automatic transmission that performs the hill hold control simultaneously with the neutral control, in some cases, for example, when the second speed is achieved, the automatic transmission is opened. (For example, a 1-2 shift valve or a 2-3 shift valve) sticks, or an abnormality occurs in a signal output system (for example, a solenoid valve or the like) for controlling the valve. When a situation in which the hill hold brake cannot be securely engaged occurs, the vehicle may be moved backward on a slope.

[0007] This means that, on a slope that normally does not retreat when the neutral control is established or not, in this case, when the neutral control is not established, the vehicle does not retreat, and only when the neutral control is established, the vehicle retreats. It means that a situation occurs.

The conditions for establishing the neutral control are generally based on the driver's intention, such as "accelerator release" and "foot brake on", as well as a driver condition such as "the engine coolant temperature is equal to or higher than a predetermined value". There are also conditions that make it impossible to predict the establishment.

Therefore, when the neutral control condition is satisfied by such a condition, the vehicle starts to retreat when the driver does not expect.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has an object to provide a creep prevention control device for an automatic transmission for a vehicle having a fail-safe function when there is a possibility of reversing on a slope. By providing the above, the above problem has been solved.

[0011]

According to the present invention, as shown in FIG. 1, even when the shift range of the automatic transmission is set to the forward traveling range, when a predetermined condition is satisfied, a forward clutch is provided. An automatic transmission for a vehicle, in which a neutral state is formed by releasing C1 to prevent the occurrence of creep, and a predetermined gear is achieved, thereby preventing the vehicle from moving backward by the brake B1 which forms the predetermined gear. In the creep prevention control device of the above, the predetermined gear position achievement availability determination means for determining whether or not the predetermined gear position can be achieved, and when the means determines that it is impossible to achieve the predetermined gear position, Means for prohibiting the release of the forward clutch are provided, thereby solving the above problem.

[0012]

According to the creep prevention control device of the present invention, when it is not possible to achieve a predetermined gear position in which the brake B1 used for hill hold is engaged, disengagement of the forward clutch is prohibited and neutral control is performed. Absent.
Therefore, when performing the neutral control, the hill hold control is always executed to prevent the vehicle from moving backward.
Further, when the hill hold control cannot be executed, the vehicle does not enter the neutral control, so that creep occurs and the vehicle does not move backward in any case.

[0013]

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

FIG. 2 is an overall schematic diagram of an automatic transmission combined with an electronic fuel injection engine for an automobile.

This automatic transmission has a torque converter 2
0, overdrive mechanism 40, three forward steps, one reverse step
And a stepped underdrive mechanism 60.

The torque converter 20 includes a pump 2
1, a turbine 22, a stator 23, and a lock-up clutch 24. The output of the crankshaft 10 of the engine 1 is
Transmit to 0.

The overdrive mechanism 40 includes a sun gear 43, a ring gear 44, a planetary pinion 42,
And a set of planetary gear units consisting of
The rotational state of the planetary gear unit is controlled by a clutch C0, a brake B0, and a one-way clutch F0.

The underdrive mechanism 60 includes two sets of planetary gear units including a common sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67. The rotation state and the connection state with the overdrive mechanism 40 are controlled by clutches C1, C2, brakes B1 to B3, and one-way clutches F1, F2.

On the other hand, the engine 1 includes a main throttle valve 2A and a sub throttle valve 2
B, two injectors, an injector 3 for injecting fuel, an ignition coil 4 for ignition, and the like.

The main throttle valve 2A rotates in conjunction with an accelerator pedal provided in the driver's seat. The sub-throttle valve 2A controls the engine torque when the computer 84 controls the engine, the automatic transmission, and the like.

A computer 84 for controlling the engine 1 and the automatic transmission includes a throttle sensor 80 for detecting a throttle opening θ for reflecting the load of the engine 1.
A vehicle speed sensor (rotation speed sensor of the output shaft 70) 82 for detecting the vehicle speed N0, and Nc for detecting the rotation speed Nc0 of the clutch C0
0 sensor 99, shift position switch 5 for outputting a shift position signal, brake switch 6 for outputting a signal when a foot brake is depressed, engine speed N
Signals for various controls such as a Ne sensor 7 for detecting e, an idle switch 8 for outputting a state of an idle contact, and a water temperature switch 9 for detecting a cooling water temperature T of the engine are inputted.

Since the rotational speed Nc0 of the clutch C0 is the same as the turbine rotational speed Nt of the torque converter section 20 from the first speed to the third speed, in this embodiment, the detection of the turbine rotational speed Nt is performed. The Nc0 sensor 99 is used as a means.

The computer 84 calculates the fuel injection amount, the optimal ignition timing, the target throttle opening, and the like using the input signals from the respective sensors, switches, and the like as parameters, and calculates the injector 3, the ignition coil 4, the main and sub throttle valves 2A, 2B is controlled to control the operating state of the engine.

The computer 84 also operates the solenoid valves S1 and S2 in the hydraulic control circuit 106, which will be described later, according to a preset throttle opening-vehicle speed shift point map.
, S3, S4, etc., are driven and controlled, and a shift control is performed by performing a combination of engagement of each clutch and brake as shown in FIG.

Here, the clutch C1 corresponds to a forward clutch that is released during creep reduction control, and the brake B1 corresponds to a brake that is engaged during hill hold control.

When the shift range is in the forward running range, the forward clutch C1 is in the engaged state, and the forward running is enabled. Even if the shift range is the forward travel range, when the throttle opening .theta. Is zero (or the idle contact is ON) and the vehicle speed is zero (including substantially zero), the engagement of the clutch C1 is performed. When the pressure is reduced, the automatic transmission is shifted to the neutral state (creep reduction control), and the brake B1 is engaged to activate the hill hold function (hill hold control).

Next, an example of a hydraulic control device for executing creep reduction control and hill hold control will be described with reference to FIG.

In the figure, reference numeral 110 indicates a manual shift valve. This manual shift valve 1
10 has a hydraulic input port 114. The hydraulic pressure input port 114 is supplied with a line pressure PL sucked up by an oil pump 120 and regulated by a primary regulator valve 124 via an oil passage 126. The manual shift valve 110 has a spool 112 driven by a manual shift lever (not shown), and connects the hydraulic input port 114 to the D range port 116 when the manual shift range is the D range. When the manual shift range is the S range (two ranges), the hydraulic pressure input port 114 is connected to the S range port 118.

D range port 116 is connected to oil passages 300 and 30.
The S range port 118 is connected to the port 146 of the 2-3 shift valve 140 through the oil passage 304.
−3 is connected to the port 148 of the shift valve 140.

The 2-3 shift valve 140 is provided on the spool 1
42. When no hydraulic pressure is supplied to the port 144, the spool 142 is in the raised position shown in the right half of the drawing, and connects the port 146 to the port 150,
In addition, the port 148 communicates with the port 152. On the other hand, when hydraulic pressure is being supplied to the port 144, the port 144 is at the lowered position shown in the left half of the figure, and cuts off the communication between the port 146 and the port 150 and cuts off the communication between the port 148 and the port 152. , Port 152 communicate with the drain port 154.

The supply of control oil pressure to the port 144 is as follows:
This is performed in a known manner by a solenoid valve S1,
The oil pressure is supplied to the port 144 only when the speed stage or the overdrive stage (fourth speed stage) is achieved. Therefore, the spool 142 is at the raised position when the first speed or the second speed is achieved, and is at the lowered position when the third speed or the overdrive speed is achieved.

The solenoid valve S1 is of a normally closed type. When the solenoid valve S1 is "ON", the pressure is supplied to the port 144, and when the solenoid valve S1 is OFF, the pressure disappears. Therefore, when the first speed or the second speed is achieved, the solenoid valve S1
To “ON” to release the pressure, and when the third speed stage or the overdrive stage is achieved, the solenoid valve S1 is turned “OF”.
F "and supply pressure.

The port 150 is connected to a B1 control valve 18 for hill hold control described later by an oil passage 306.
0 port 186. Port 152 is
Oil passage 308, second coast modulator valve 16
0, port 1 of check valve 170 via oil passage 310
72.

The check valve 170 is connected to the inlet port 17.
In addition to the inlet port 174 and the outlet port 174, when an oil pressure is supplied to the inlet port 172 by the action of the check ball 178, the inlet port 174 is closed. When the hydraulic pressure is supplied to the inlet port 172, the inlet port 172 is closed. The inlet port 174 is connected to the port 188 of the B1 control valve 180 by an oil passage 312, and the outlet port 176 is connected to the
It is connected to the port 136 of the two-shift valve 130.

The 1-2 shift valve 130 is connected to the spool 13
2 When hydraulic pressure is not supplied to the port 134, the spool 132 is in the raised position shown in the left half of the figure and communicates the ports 136 and 138. On the other hand, when hydraulic pressure is supplied to the port 134, the right half of the figure is The port 136 is disconnected from the drain port 139 by shutting off the ports 136 and 138 at the lower position shown in FIG. The port 138 is connected to the oil passage 316.
Connected to the brake B1.

The port 134 has a solenoid valve S2
Due to the operation described above, the hydraulic pressure is supplied only when the first speed is achieved, whereby the spool 132 is set to the raised position when the second speed, the third speed, or the overdrive speed is achieved, and when the first speed is achieved. Only the lowered position is set.

The solenoid valve S2 is also a normally closed type. When the solenoid valve S2 is "ON", the pressure is supplied to the port 134, and when the solenoid valve S2 is "OFF", there is no pressure.

The relationship between the operation signals to the solenoid valves S1 and S2 and the shift speed is as shown in the table below.

[0039]

The B1 control valve 180 provided for hill hold control includes a spool 182 and a plug 18
And 4. When the spool 182 is in the raised position shown in the right half of the figure, the ports 186 and 188 communicate with each other, and the ports 190 and 192 are shut off so that the port 1
92 is connected to the drain port 198. On the other hand, when in the lowered position shown in the left half of the figure, the port 186 is closed, the port 188 communicates with the drain port 187, and the ports 190 and 192 communicate.

The port 190 is connected to the oil passage 314 and the oil passage 300
Is connected to the D range port 116 of the manual shift valve 110, and the port 192 is connected by an oil passage 316 to the port 208 of the C1 control valve 200 provided for neutral control (for creep reduction control).

The spool 182 of the B1 control valve 180 is driven by the hydraulic pressure applied to the ports 194 and 196, and when at least one of the ports 194 and 196 is supplied with the signal hydraulic pressure Ps equal to or higher than the predetermined value Psset, the left half position That is, the hill hold control is released. When the signal oil pressure Ps equal to or greater than the predetermined value Psset is not supplied to any of the ports 194 and 196, the port is located at the right half position, that is, the hill hold control position. Port 194 is oil passage 318
As a result, the oil pressure is connected to the oil passage 320 to supply the signal oil pressure Ps of the oil passage 320.

The solenoid valve S3 provided as the main control means of the C1 control valve 200 for the neutral control and the B1 control valve 180 for the hill hold control operates according to the duty ratio D of the pulse signal applied to its electromagnetic coil. , A signal pressure Ps corresponding to the duty ratio D is generated in the oil passage 320. The solenoid valve S3 is constituted by a so-called normally closed solenoid valve, whereby the signal oil pressure Ps of the oil passage 320 decreases as the duty ratio D applied to the electromagnetic coil increases. Oil passage 32
0 is the throttle 280, the oil passage 322, the modulator valve 25
0, which is connected to the oil passage 126 via the oil passage 324, whereby the oil pressure 322 regulated to a predetermined constant pressure by the modulator valve 250 is supplied to the oil passage 322.

The oil passage 320 is connected to a port 194 of the B1 control valve 180 by an oil passage 318, and is connected to a port 210 of the C1 control valve 200 via an oil passage 326 and a throttle 282.

The C1 control valve 200 has a spool 202 and two plugs 204 and 206.
Spool 202 is connected to oil passage 3 by oil passages 328 and 314.
00 and a port 21 to which the line pressure PL is supplied.
By controlling the degree of communication with the second drain port 216, the hydraulic pressure at the outlet port 214 is adjusted. The pressure adjustment value is increased in accordance with the urging force applied to the spool 202 by the compression coil spring 218 and the pressing force applied directly to the spool 202 by the plugs 204 and 206. Exit port 214
Is connected to the clutch C1 via a C1 relay valve 270 provided for fail-safe of the C1 control valve 200.

That is, the C1 relay valve 270 is arranged between the port 214 of the C1 control valve 200 and the clutch C1. The port 214 of the C1 control valve 200 and the C1 relay valve 270
Port 272 is connected by an oil passage 330. The clutch C1 and the port 276 of the C1 relay valve 270 are connected by an oil passage 340. Further, a D range line pressure PL generated at the D range port 116 of the manual valve 110 is guided to a port 274 of the C1 relay valve 270 by an oil passage 336.

In the middle of the oil passage 340, a throttle 284
Is provided. Also, the oil passage 340 and the oil passage 300
It is connected via a check valve 260. The check valve 260 is configured to allow only the flow of oil from the oil passage 340 to the oil passage 300, that is, the drain flow of the oil.

The hydraulic control device of the present embodiment is provided with another solenoid valve S4. The solenoid valve S4 controls the oil pressure of the oil passage 410 to a high pressure or a low pressure by being turned on / off. The oil passage 410 is connected via a throttle 411 and an oil passage 412 to an oil passage 126 that is adjusted to the line pressure PL by the primary regulator valve 124.

The C1 relay valve 270 has two control signal input (pilot) ports 277 and 278 for switching control of the spool position of the C1 relay valve 270 in the same direction. , 27
8, when the oil pressure higher than the set pressure is introduced, it is located at the right half position in FIG.
To communicate with Also, when the pressures of both ports 277 and 278 are both lower than the set pressure, the port is located at the left half position in FIG.

The one control signal input port 277
Is connected to the oil passage 320 via an oil passage 334, and is connected to a port 277 through a valve C3 controlled by a solenoid valve S3.
1 A pressure Ps for control valve control is introduced. Also, the other control signal input port 27
Numeral 8 is connected to an oil passage 410 via an oil passage 413, and a hydraulic pressure controlled by a solenoid valve S4 is introduced into a port 278.

The control signal input port 196 of the B1 control valve 180 is connected via an oil passage 414 to an oil passage 410 whose pressure is controlled by a solenoid valve S4.

Further, in this apparatus, the drain port 216 for regulating the pressure of the C1 control valve 200 is connected to the port 192 of the B1 control valve 180,
1 When the control valve 180 is in the brake release position (Fig. 4
When the D range line pressure PL is
C1 is introduced into the drain port 216 together with the control port 208 of the control valve 200.

Next, the operation of the hydraulic control device having the above configuration will be described.

When the manual shift range is set to "D range", the solenoid valve S2 is set to "OFF",
When the first speed is established by turning ON the solenoid valve S1, the 1-2 shift valve 1
30 is in the lowered position, and the spool 142 of the 2-3 shift valve 140 is in the raised position.

The creep reduction control and the hill hold control have not been started yet, and the solenoid valve S3 is turned off.
While the signal is being given, the signal oil pressure Ps of the oil passage 320
Is set to the same oil pressure as the output oil pressure Pm of the modulator valve 250, and this oil pressure is set to the B1 control valve 180.
Port 194 and the port 210 of the C1 control valve 200. Therefore, at this time, B
1 The spool 180 of the control valve 180 is located at the left position, that is, the hill hold control release position, whereby the port 186 is closed and the hill hold control output port 188 is connected to the drain port 187.

Further, since the port 190 communicates with the port 192, the line pressure PL from the oil passages 300 and 314 is increased.
Enters the port 208 of the C1 control valve 200 through the oil passage 316, and the C1 control valve 2
00 is located at the left position, that is, the normal mode position, by the action of the line pressure PL supplied to the port 208 in addition to the signal oil pressure Ps applied to the port 210.

As a result, the line pressure PL applied to the port 212 by the drain port 216 being completely closed is not reduced, but is directly introduced into the clutch C1 from the port 214 via the oil passage 330. Therefore, at this time, the clutch C1 is completely engaged, and the first speed is achieved.

Since the port 186 of the B1 control valve 180 is closed, the port 188 is drain-connected, and the port 13 of the 1-2 shift valve 130 is connected.
6 is also closed and port 138 is drain connected,
No hydraulic pressure is supplied to the brake B1 and the brake B1
Are maintained in a released state.

Next, when the manual shift range is set to the "D range", the throttle opening of the engine 1 is returned to the idle opening position (idle contact ON), and the vehicle speed is close to zero. When the pressure falls below a predetermined value, control commands are issued to the solenoid valves S1 to S4 to execute creep reduction control and hill hold control.

That is, a pulse signal is given to the solenoid valve S3, and its duty ratio D is increased with the passage of time. In response to the increase in the duty ratio D, the signal oil pressure Ps of the oil passage 320 gradually decreases with the passage of time, and when the signal oil pressure Ps decreases to a predetermined value Psset, the spool 182 of the B1 control valve 180 moves to the position shown in FIG. To the right side (hill hold control side), and the communication port of port 188 is connected to drain port 187.
To port 186. Further, the communication port of the port 192 is switched from the port 190 to the drain port 198.

Therefore, since the line pressure PL is not supplied to the port 208, the pressure adjustment value of the C1 control valve 200, that is, the engagement pressure of the clutch C1 is set by the signal oil pressure Ps applied to the port 210, and the signal oil pressure Ps
The drain port 216 is opened with the decrease of. As a result, the engagement pressure supplied from the port 214 to the clutch C1 decreases, and this causes the clutch C1 to slip. Thus, the automatic transmission is in the same state as in the neutral state, and the occurrence of creep is prevented at the same time as the idle vibration is reduced. That is, creep reduction control is executed.

At the same time, both the solenoid valves S1 and S2 are turned "ON" to achieve the second speed stage.
Operated. At this time, since the ports 186 and 188 of the B1 control valve 180 communicate with each other as described above, when the solenoid valve S1 is turned "ON", the spool 142 of the 2-3 shift valve 140 is raised, that is, the first speed. The manual shift valve 11 is operated by operating the shift position to achieve the second speed or the second speed.
0, the line pressure PL of the D range port 116 is
0, 302, port 146 of 2-3 shift valve 140
And 150, oil passage 306, B1 control valve 18
0 through ports 186 and 188, an oil passage 312, a check valve 170, and an oil passage 314.
It reaches port 136 at 0.

Then, the solenoid valve S2 is turned "ON".
As a result, the spool 132 of the 1-2 shift valve 130 is operated to the raised position, that is, the switching position for achieving the second speed, the third speed, or the overdrive stage (fourth speed). Line pressure PL reached
Is supplied from the port 138 to the brake B1 via the oil passage 316, the brake B1 is engaged, and the sun gear 61 (FIG.
Reference) is fixed. Therefore, the sun gear 6
1 and the carrier 67 is prevented from rotating backward by the action of the one-way clutch F2, so that the planetary pinion 65 is prevented from rotating backward, whereby the ring gear 6 is prevented from rotating.
3 is prevented, the output shaft 70 is prevented from rotating in the reverse direction of the vehicle, and so-called hill hold control is executed.

That is, even when the manual shift range is the "D range", the same shift speed as the second speed in the "S range" is achieved by the engagement of the brake B1. Thus, the vehicle is prevented from moving backward.

The above description has been made in the case where there is no abnormality in the solenoid valves S1 and S2, and there is no abnormality in the 2-3 shift valve 140 or the 1-2 shift valve 130. The following problem may occur when the error occurs.

That is, for example, when the solenoid valve S1 does not perform a normal ON operation, or when the 2-3 shift valve sticks on the third and fourth speeds, the second speed state cannot be achieved. Cannot be engaged. Similarly, when the solenoid valve S2 does not perform a normal ON operation, or when the 1-2 shift valve sticks on the first speed side, the second speed state cannot be achieved, so that the brake B1 can be engaged. become unable.

If it is attempted to execute the creep reduction control, but a situation occurs in which the shift speed at which the brake B1 is engaged cannot be achieved, neutral control, that is, the engagement pressure of the forward clutch C1 is maintained. If the control for canceling (or reducing) is performed, there is a possibility that the vehicle will retreat on a slope. The disadvantages in this regard have already been described in detail.

Therefore, in the apparatus according to the present embodiment, when such a situation is likely to occur, that is, when a predetermined gear (the brake B1 in this embodiment) for engaging the hill hold brake (the brake B1 in this embodiment) is applied. In the embodiment, when the second speed in the two ranges cannot be achieved, a function is provided for judging it and for inhibiting the neutral control based on the judgment.

Hereinafter, the function will be described in detail with reference to the flowcharts of FIGS.

FIG. 5 shows the flow of the routine for determining whether the second speed stage can be achieved in the above-described embodiment, and FIG. 6 shows the flow of the creep prevention control routine. These routines are one of the main routines for automatic transmission control and engine control.
Are defined as two subroutines, each of which is repeatedly executed at a predetermined very short cycle.

First, when the process of FIG. 5 is started, it is determined in step 500 whether or not the manual shift range is the “D range”. If not "D range", step 5
In step 08, the value of the fail counter C is reset to "0".

In the case of "D range", steps 501 to
At 507, the solenoid valves S1, S2, and 2
The failure determination of the -3 shift valve 150 and the 1-2 shift valve 130 is performed.

That is, first, at step 501, it is determined whether the solenoid valve S1 is normal, and at step 502, it is determined whether the solenoid valve S2 is normal. The failure determination of the solenoid valves S1 and S2 is performed by another routine (not shown) by a known method. The failure state includes a short-circuit failure or a disconnection failure.

Either solenoid valve (S1 or S1
If 2) is a failure, the process proceeds to step 509, and the value of the fail counter C is incremented by "1".

Each of the solenoid valves (S1 and S2
If) is not a failure, the process proceeds to step 503. Then, in this step 503, it is determined whether or not the signal to the solenoid valve S1 is "OFF".

When the signal to the solenoid valve S1 is "OF"
If it is not "F" (in the case of NO), it means that "first speed" or "second speed" has been commanded, and it is then determined in step 504 whether the power is on or coasted. I do. In the power-on state, the process proceeds to step 506,
Here, the following relation [turbine rotation speed Nco] <[output shaft rotation speed No × i2-
ΔN] is determined. Here, i2 is the gear ratio of the second speed, and ΔN is a constant.

In the case of "YES", it can be determined that the third speed or higher is established even though the first speed or the second speed is instructed. This means that the stick state toward the third and fourth speeds has been detected. Therefore, the routine proceeds to step 509, where the fail counter C is incremented by one.

The determination in step 504 is "NO".
In the case of, step 50
Proceeding to 8, reset the fail counter C to "0".

If "NO" in the step 506, it is next determined whether or not the command signal to the solenoid valve S2 is "ON" in a step 505 in order to determine the failure of the 1-2 shift valve 150. . Here, when the solenoid valve S2 is "OFF", it means that the "first speed" has been commanded. In this case, since the shift speed is not related to the fail determination, the process proceeds to step 508.
The fail counter C is set to “0”.

If the command signal to the solenoid valve S2 is "ON", the determination in step 505 is "YES".
Becomes In this case, it means that "second speed" has been commanded, and the routine proceeds to step 507, where the following relationship [turbine rotational speed Nco]> [output shaft rotational speed No × i2 +
ΔN] is determined. Here, i2 = the gear ratio of the second speed, and ΔN = a constant.

When this input / output relational expression holds (YE
The case of S) means that the actual shift speed is “first speed”. Therefore, although the command is for the "second speed", it is actually "first speed", so that the 1-2 shift valve 150 fails to the first speed side. Can be considered to be. Therefore, in this case, the process proceeds to step 509, and the value of the fail counter C is incremented by one.

If the determination in step 507 is "NO", it means that the actual shift speed is "second speed", and since it matches the command signal, it is determined that the speed is normal and step 508 is performed. To reset the fail counter to "0".

When the process proceeds to step 509,
Next, in step 510, it is checked how many times the fail determination has been made. If the number of failures is counted more than a predetermined number of times, it is finally determined that "failure has occurred", the fail flag F1 is set in step 511, and the next Or return to the main routine.

If the number of counts is less than the predetermined number, the determination is repeated. If it is not failed,
After resetting the fail counter C to "0" in step 508, the judgment is repeated again. Therefore, only when the same failure is confirmed a predetermined number of times continuously, it is determined that a failure has occurred, and the fail flag is set.
The fact that the flag F1 is set means that the shift speed (second speed) at which the brake B1 is engaged cannot be achieved.

Next, the contents of the creep reduction (= prevention) control will be described with reference to the flowchart shown in FIG.

When the processing of the routine in FIG. 6 is started, the conditions for establishing the creep prevention control are determined in steps 600 to 606. The conditions include the following.

The shift range is the drive range (step 600). The idle contact signal is on (step 601). The aforementioned fail flag F1 is “0” (step 60).
2) The foot brake signal is ON (Step 603) The vehicle speed V is equal to or less than a predetermined value V0 close to zero (Step 604) The engine coolant temperature is equal to or more than a predetermined value T1 (Step 60)
5) The engine speed Ne is equal to or less than a predetermined value Ne0 (step 6).
06)

Then, when all of these conditions are satisfied, anti-creep control is executed. here,,,
The conditions (1) and (2) correspond to conditions for substantially realizing the creep prevention control, and the conditions (2) and (3) correspond to conditions detected for confirmation from the viewpoint of fail-safe. The condition (1) corresponds to the engagement condition of the hill hold brake B1.

When all of these conditions are satisfied, step 60
Proceeding to 7, the opening of the sub-throttle valve 2B is closed to the predetermined value θs1. This θs1 is set to a value immediately before the engine torque is reduced.

Thereafter, the routine proceeds to step 608, where a signal for releasing the forward clutch C1 is issued, and the neutral state is formed by the above-described method to create the anti-creep state. In step 621, an "ON" signal is output to the solenoid valves S1 and S2 to form a second speed in which the hill hold brake B1 can be engaged.

On the other hand, when it is determined that the condition is not satisfied in any one of steps 600 to 606, the creep prevention control is stopped (prohibited) or canceled. In this case, step 600
The method of releasing differs depending on which of the conditions 606 is not satisfied.

If the condition of step 601 is satisfied, that is, if the idle contact is turned off (the accelerator pedal is depressed), the creep prevention control is released, step 6
In step 09, it is determined whether the torque-down control has ended, that is, whether or not the end timing of the closing control of the sub-throttle valve 2B has come. Initially, this determination is “NO”, so the process proceeds to step 610.

In step 610, the opening of the sub-throttle valve 2B is closed to a predetermined value θs2 in order to execute the torque down control when the creep prevention control is canceled. As a result, the torque is quickly reduced.

Next, the routine proceeds to step 612, where a command to engage the forward clutch is issued to form the first speed. In step 622, a solenoid signal according to a normal shift map is output.

Eventually, when the engagement of the forward clutch is advanced, and it is determined in step 609 that the condition for determining the termination is satisfied, the routine proceeds to step 611, where the sub-throttle valve 2B is fully opened, and the torque down control is terminated. . That is, according to this embodiment, the forward clutch can be engaged in a state where the engine torque is reduced, so that the forward clutch can be quickly and completely engaged with a small shift shock, and furthermore, the forward clutch can be engaged with the engine at an optimal timing. Since the torque is restored, the vehicle can be quickly started at the same time as the engagement is completed.

If the creep prevention control is prohibited due to the failure of the condition in step 602, that is, if it is determined that the gear position at which the hill hold brake B1 cannot be engaged cannot be achieved, the creep reduction control is directly performed. If executed, there is a possibility that the vehicle will move backward. Therefore, the determination in step 601 is exactly the same as when the determination in step 601 is NO.
To perform the same processing.

On the other hand, the anti-creep control is executed in step 603.
If any one of the steps 606 to 606 is released because it is not established, the process first proceeds to step 614 to determine whether or not the forward clutch has been completely engaged. Initially, it is determined that the full engagement has not been achieved, so the routine proceeds to step 617, where the sub-throttle valve 2B is fully opened,
Next, at step 618, the forward clutch is engaged while gradual.

That is, when the anti-creep control is released due to a factor other than the accelerator, no response is required for starting, and the generated engine torque is low, so that the forward clutch is engaged and the engagement is gradually reduced. Let me
In particular, the engine torque is not reduced.

When it is determined in step 614 that complete engagement has been reached, the flow proceeds to 609,
Since the vehicle has already been fully engaged, the determination here is always "YES", and the routine proceeds to step 611, where the sub-throttle is fully opened, and at step 61
2 keeps the forward clutch completely engaged.

When it is determined that the shift range is not the drive range, the process proceeds to step 613 or step 616. When the shift range is not the drive range, the creep prevention control is not executed. That is, it is determined in step 614 whether or not the forward clutch has been completely engaged. If the forward clutch is engaged, the process proceeds to step 617, where the sub-throttle valve 2B is fully opened, and in step 618, the forward clutch is slowly released. The engagement is performed, and the process proceeds to step 622. When the engagement is completed, the flow proceeds from step 614 to 609, 611, and 612, so that the forward clutch is completely engaged.

On the other hand, when it is determined that the shift range is not the drive range, 2 range, or L range,
Proceeding to step 619, the sub-throttle valve 2B is fully opened and is not in the forward range.
, The forward clutch is completely released. Then, the routine proceeds to step 622, where the solenoid is driven according to the normal shift map.

As described above, the solenoid valves S1 and S
2, 2-3 shift valve 150, 1-2 shift valve 1
30 has failed and brake B
When the second speed in which 1 is engaged cannot be achieved, the release of the forward clutch C1 is prohibited. Therefore, even in the event of a failure, the possibility of retreating on a slope can be eliminated.

[0103]

As described above, according to the anti-creep control apparatus of the present invention, when the predetermined gear stage in which the brake for reverse movement used for hill hold cannot be engaged, the forward clutch is disengaged. Prohibit release of joint pressure and do not perform neutral control. Therefore, when performing the neutral control, the hill hold control is always executed to prevent the vehicle from retreating, and there is no possibility of the vehicle retreating.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of an entire system including an automatic transmission to which an embodiment of the present invention is applied;

FIG. 3 is a diagram showing an engaged and disengaged state of a friction engagement device at each shift speed in the automatic transmission.

FIG. 4 is a diagram showing a structure of a hydraulic control device of the automatic transmission according to the embodiment.

FIG. 5 is a flowchart showing a part of control contents in the embodiment.

FIG. 6 is a flowchart showing another control content in the embodiment.

[Explanation of symbols]

 C1: forward clutch, B1: brake for hill hold, S1, S2: solenoid valve, 130 ... 2-3 shift valve, 150 ... 1-2 shift valve.

Continuation of the front page (56) References JP-A-5-240340 (JP, A) JP-A-62-2737 (JP, A) JP-A-61-244956 (JP, A) Jpn. , U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16H 59/00-63/00

Claims (1)

(57) [Claims] When a predetermined condition is satisfied even when the shift range of the automatic transmission is set to the forward traveling range, the forward clutch is released to form a neutral state and the occurrence of creep. A creep prevention control device for an automatic transmission for a vehicle, which prevents and prevents a vehicle from moving backward by a brake that forms the predetermined shift speed by achieving the predetermined shift speed. Means for determining whether a predetermined gear position can be achieved, and means for prohibiting disengagement of the forward clutch when the means determines that the predetermined gear position cannot be achieved. Anti-creep control system for automatic transmissions for vehicles.