JPH11311326A - Stall preventing device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the engine stall in the case of suddenly operating a brake by disconnecting a lockup clutch so as to cancel the slip control, and disconnecting a clutch. SOLUTION: A second control unit 28 outputs the lockup solenoid signal to a lockup control solenoid 20 and outputs the neutral solenoid signal to a neutral control solenoid, and while the slip control number of revolution is input to the second control unit 28 from a slip control number of revolution detecting means 12, and the car speed is input thereto from a car speed sensor 18. When the second control unit 28 judges the time of sudden braking, the second control unit 28 disconnects the lockup clutch 8 so as to cancel the slip control, and disconnects the neutral control clutch 16. The slip control is canceled by perfectly disconnecting the engagement of the lockup clutch 8 so as to provide the converter condition, and while turning the slip control signal off, and turning the fuel cut control off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stall prevention device for an automatic transmission, and more particularly to a control device that disconnects a lock-up clutch to release slip control when it is determined that sudden braking has occurred, and that at least one The present invention relates to a stall prevention device for an automatic transmission that controls to disengage a clutch and reliably prevents a stall that occurs during a sudden braking.

[0002]

2. Description of the Related Art In vehicles equipped with an automatic transmission,
There was a bad reputation such as "the engine brake does not function at the time of deceleration" or "the fuel consumption is lower than the vehicle equipped with a manual transmission during normal driving".

[0003] This is because the transmission efficiency of the torque converter used in the automatic transmission is low, and the braking force from the driving wheels cannot be sufficiently transmitted to the engine. Unnecessary slippage occurs in the torque converter during running, and the fuel efficiency is deteriorated.

[0004] Regardless of the automatic transmission and the manual transmission,
In order to reduce fuel consumption, fuel cut control for stopping fuel supply during deceleration is widely used. This fuel cut control is released when the engine speed falls below a certain value.

As the stall prevention device for the automatic transmission, there is one disclosed in Japanese Patent Application Laid-Open No. 6-94122. A lock control clutch slip control device disclosed in this publication includes a throttle opening detection unit that detects a fully closed state of a throttle valve of an internal combustion engine mounted on a vehicle, and a device that determines whether rapid deceleration is performed during a brake operation of the vehicle. A rapid deceleration determining means for determining whether the throttle valve has been fully closed by the throttle fully closed detecting means while the vehicle is running, and determining whether or not the rapid deceleration determining means has made a sudden deceleration determination. At the time of sudden deceleration determination, the target slip ratio set by the target slip ratio set by the target slip ratio set by giving the target slip ratio of the lock-up clutch in the automatic transmission mounted on the vehicle. And a slip ratio control means for controlling a slip ratio of the lock-up clutch based on the vehicle speed. On which realized above and emission reduction, during rapid deceleration, immediately controls the lock-up clutch on the open side, thereby preventing engine stall.

[0006]

In a conventional automatic transmission, when a lock-up clutch is engaged during deceleration in order to increase the engine braking effect of a vehicle equipped with the automatic transmission, fuel efficiency is improved. Since the fuel cut control is performed at the same time, the engine speed is rapidly reduced, and the fuel cut control is canceled early.

Therefore, in order to continue the fuel cut control for a long time, a slip control for controlling the lock-up clutch to a half-clutch state, that is, a slip state during deceleration is employed.

For this reason, the fuel cut control can be continued for a long time while improving the engine braking effect of the automatic transmission.

However, when the vehicle speed rapidly decreases in a short period of time, such as in the case of sudden braking (also referred to as "panic braking"), there is no time to complete the slip control. In other words, the lock-up clutch remains in the lock-up state, and at the time of this rapid braking, the rate of decrease in the engine speed is large, so that the fuel cut control cannot be canceled in time, and as shown in FIG. There is an inconvenience of falling into a stall (also called "engine stall") after being performed.

Here, the slip control will be described. In the slip control, the lock clutch is put into a slip state, that is, a half-clutch state to improve the fuel efficiency. At the time of acceleration, the engine speed is suppressed to improve the fuel efficiency, and the speed is reduced. At times, the engine speed is reduced and the fuel cut control state is set to improve fuel economy.

[0011]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a torque converter provided on the engine side, a lock-up clutch disposed on the torque converter, and a method for detecting the engine speed in order to eliminate the above-mentioned disadvantages. Engine speed detecting means for detecting slip control speed, slip control speed detecting means for detecting slip control speed, and at least one clutch provided between the engine side and the input shaft side. When the engine speed from the means and the slip control speed from the slip control speed detecting means are input and a predetermined deceleration slip condition is satisfied, the lock-up clutch is slipped according to the engine speed and the slip control speed. In an automatic transmission connected with control means for performing slip control, When it is determined that the vehicle is in the off state, a function of disconnecting the lock-up clutch to release the slip control and controlling to disconnect at least one clutch is added to the control means. I do.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
When it is determined that the vehicle is suddenly braked, the control means disconnects the lock-up clutch to release the slip control, controls to disconnect at least one clutch, weakens the engagement state between the engine and the input shaft, Stalls that occur during sudden braking are prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 4 show an embodiment of the present invention. In FIG. 2, reference numeral 2 denotes an engine mounted on a vehicle (not shown), and reference numeral 4 denotes an automatic transmission.

As shown in FIG. 2, the automatic transmission 2 includes a torque converter 6 provided on the engine 2 side, a lock-up clutch 8 provided on the torque converter 6,
Engine speed detecting means 10 for detecting engine speed
A slip control rotation speed detecting means 12 for detecting a slip control rotation speed, and at least one clutch provided between the engine 2 side and the input shaft 14 side, for example, one neutral (N) control clutch 16. Having.

A vehicle speed sensor 18 for detecting a vehicle speed is provided on the output side of the automatic transmission 4, and a lock-up control solenoid 20 is provided near the lock-up clutch 8 of the torque converter 6, and is provided near the neutral control clutch 16. Is provided with a neutral control solenoid 22.

The engine speed detecting means 10
When the engine speed and the slip control speed from the slip control speed detector 12 are input and the predetermined deceleration slip condition is satisfied, the lock-up clutch 8 is slipped by the engine speed and the slip control speed. A control means 24 for performing slip control for setting the state is connected to the automatic transmission 4 and provided.

At this time, when it is determined that the vehicle is suddenly braked, the lock-up clutch 8 is disengaged to release the slip control, and a control function for disengaging at least one clutch, ie, the neutral control clutch 16, is provided. , Provided in addition to the control means 24.

More specifically, the control means 24 receives the detection signal from the vehicle speed sensor 18 and determines the deceleration rate of the vehicle speed.
The vehicle speed is calculated, and the vehicle speed, which is the deceleration rate, is equal to a predetermined value Xkm /
h or more, that is, when the formula Δvehicle speed ≧ X (km / h) holds, it is determined that it is the time of sudden braking.

As shown in FIG. 2, the control means 24 includes a first control unit (ECU, engine control unit) 26 and a second control unit (TCU, transmission control unit).
A control unit) 28.

The second control section 28 outputs a lock-up solenoid signal as a control signal S1 to the lock-up control solenoid 20, and outputs a control signal S2 as a neutral solenoid signal to the neutral control solenoid 22 to perform slip control rotation. A slip control rotation speed as a detection signal S3 from the number detection means 12 is input, and a vehicle speed as a detection signal S4 from the vehicle speed sensor 18 is input.

The first control unit 26 includes an engine speed pulse as a detection signal S5 from the engine speed detection means 10, a slip control signal as a signal S6 and a neutral signal S7 as a signal S6 from the second control unit 28. A control signal, a D range signal as a signal S8, and a throttle opening as a detection signal S11 from a throttle opening sensor 30 provided in the engine 2 are input.
9 engine speed and signal S10 throttle DU
And a TY output.

The second control unit 2 of the control means 24
8 determines the panic brake state, that is, the time of sudden braking. At the time of sudden braking, control for disconnecting the lock-up clutch 8 to release the slip control and disengaging at least one neutral clutch 16 as a clutch is performed. Will be

At this time, the above-mentioned release of the slip control means that the engagement of the lock-up clutch 8 is completely disengaged to set the converter state, and at the same time, the slip control signal is turned off and the fuel cut control is turned off to stop. It is to let.

Here, the slip control by the control means 24 will be described. The second control unit 28 of the control means 24 controls the slip control rotation speed as the detection signal S3 from the slip control rotation speed detection means 12 and the vehicle speed. Sensor 18
, The vehicle speed as the detection signal S4, the engine speed as the signal S9 from the first control unit 26, and the throttle DUTY output as the signal S10 are input to a predetermined deceleration slip condition, that is, (1) vehicle speed ≧ Vh (km / H) (2) It is determined whether or not the throttle duty output = 0 (%) is satisfied.

If the above-mentioned deceleration slip condition is satisfied, slip control is started. This slip control compares the slip control rotation speed, which is the detection signal S3 from the slip control rotation speed detection means 12, with the engine rotation speed, which is the signal S9, and performs a feedback control using a difference between these rotation speeds as a target value. Yes, control signal S
The lock-up control solenoid 20 is controlled by one lock-up solenoid signal, and the lock-up clutch 8 is brought into a slip state.

At this time, if either the vehicle speed or the throttle duty output is outside the deceleration slip condition, the slip control is stopped.

The neutral control by the control means 24 will be described. In the state where the torque converter 6 between the engine 2 and the automatic transmission 4 is connected, the torque is reduced during the D range idling when the vehicle is stopped. Converter 6 slips, and the fuel efficiency of engine 2 decreases. Therefore, the slip of the torque converter 6 is eliminated by the neutral control, and the fuel efficiency is improved.

The second control unit 28 of the control means 24 determines when a predetermined deceleration slip condition is satisfied, that is, (1) vehicle speed ≧ Vh (km / h), and (2) throttle duty output = 0 (%). The neutral control solenoid 22 is operated by the neutral solenoid signal serving as the control signal S2 in the D range, and the neutral control clutch 16 is released. The second control unit 2 of the control means 24
8 outputs a neutral control signal as a signal S7 and a D range signal as a signal S8 to the first controller 26, and sets a target rotation speed during the neutral control.

Further, the fuel cut control by the control means 24 will be described.
The slip control signal as the signal S6 is transmitted from the control unit 28 to the first control unit 26, and the fuel cut control is performed only while the slip control signal as the signal S6 is ON.

Next, the operation of the above-described automatic transmission stall prevention device will be described with reference to the control flowchart of the first control unit (ECU) 26.

When the control program by the first control unit (ECU) 26 is started (100), as shown in FIG. 3, the ON / OFF state of the slip signal, that is, the slip control signal as the signal S6 is determined (102).

If the slip control signal is ON in the judgment (102), the fuel cut control is executed (104), and if the slip control signal is OFF in the judgment (102), the fuel cut control is executed. The control is stopped and returned to the predetermined state (104),
Thereafter, the control program by the first control unit (ECU) 26 ends (108).

A description will be given along a control flowchart by the second control unit (TCU) 28 of the stall prevention device for the automatic transmission.

When the control program by the second control unit (TCU) 28 is started (200), as shown in FIG. 1, predetermined deceleration slip conditions, that is, (1) vehicle speed ≧ Vh (km / h) (2) throttle It is determined whether or not the duty output = 0 (%) is satisfied (202).

If the judgment (202) is YES,
The slip signal, that is, the slip control signal, which is the signal S6, is turned on to shift to the execution (204) of the slip control (also referred to as "deceleration slip control").
In the case of O, the slip signal, that is, the slip control signal, which is the signal S6, is turned off to shift to a process (206) of stopping the slip control, and thereafter, the second control unit (TC
U) The process is shifted to the end (212) of the control program by 28.

After the execution of the slip control (204), it is determined whether or not the vehicle speed, which is the deceleration rate, is equal to or more than a predetermined value Xkm / h, that is, whether or not the formula Δvehicle speed ≧ X (km / h) holds (208). )I do.

Then, if the judgment (208) is NO, the process returns to the judgment (202) as to whether or not a predetermined deceleration slip condition is satisfied. Is determined, the slip control is stopped, that is, the slip control signal is turned off, the neutral control clutch 16 is released (210), and then the control program by the second control unit (TCU) 28 ends (212). ).

Thus, when it is determined that the vehicle is suddenly braked, the control means 26 controls the lock-up clutch 8
To release the slip control, control to disconnect at least one clutch, weaken the engagement state between the engine 2 and the input shaft 14, and reliably prevent stall that occurs during sudden braking. It is practically advantageous.

Further, a detection signal from the vehicle speed sensor 18 is input to calculate a vehicle speed deceleration rate △ vehicle speed. If the vehicle speed deceleration rate △ vehicle speed is equal to or more than a predetermined value Xkm / h, it is determined that a sudden braking is being performed. By providing the control means 24 for determining,
Vehicle speed sensor 1 already provided for judgment during sudden braking
8 can be used, there is no need to newly provide an acceleration (G) sensor, there is no fear that the configuration is complicated, the cost can be kept low, and it is economically advantageous.

Further, by using the neutral control clutch 16 as at least one clutch provided between the engine 2 side and the input shaft 14 side, it is not necessary to newly provide a clutch, and the configuration is complicated. There is no danger that the cost can be kept low and it is economically advantageous. Further, if the neutral control clutch 16 is disconnected, the effect that the stall generated at the time of sudden braking can be surely prevented can be easily achieved. Obtainable.

It should be noted that the present invention is not limited to the above-described embodiment, and various application modifications are possible.

For example, in the embodiment of the present invention, when it is determined that the vehicle is suddenly braked, the control means disconnects the lock-up clutch to release the slip control and controls to disconnect at least one clutch. However, instead of the function of disconnecting the lock-up clutch and releasing the slip control, when it is determined that sudden braking is being performed, the slip control of the lock-up clutch and the release of the slip control are repeated for a predetermined time, It is also possible to release the slip control by disconnecting the lock-up clutch after the elapse of the predetermined time T, and to add a function (SG1) for controlling to disconnect at least one clutch to the control means.

That is, as shown in FIG. 5, when it is determined that the vehicle is suddenly braked, the slip control signal is alternately turned on and off for a predetermined time T, so that the slip control signal is turned on for a predetermined time T. It is possible to satisfy both effects of improving fuel efficiency, which is a slip effect, and preventing stall when the slip control signal is OFF,
Since the slip hydraulic pressure and the engine speed can be smoothly reduced, and the control settings are uniform, the setting operation can be easily performed.

The slip control signal is alternately turned ON / O.
When the FF operation is performed, as shown in FIG. 6, the ON operation time is gradually reduced stepwise from TA1 to TA4, for example, and the OFF operation time is also gradually reduced stepwise from TB1 to TB4 ( SG2) or, as shown in FIG.
It is possible to use a measure (SG3) in which the N operation time is gradually reduced stepwise from TC1 to TC4 and the OFF operation time is gradually increased stepwise from TD1 to TD4.

Then, the above two measures (SG2, S2
In G3), the slip control signal is alternately turned ON / OF.
When the F operation is performed, the ON operation time and the OFF operation time change, and the balance between the respective effects of improving the fuel efficiency, which is a slip effect when the slip control signal is ON, and preventing stall when the slip control signal is OFF is changed. As a result, any setting can be made, and usability can be improved.

[0047]

As described above in detail, according to the present invention, a torque converter provided on the engine side, a lock-up clutch provided on the torque converter, and an engine speed detecting means for detecting the engine speed are provided. And a slip control rotation speed detecting means for detecting a slip control rotation speed, and at least one clutch provided between the engine side and the input shaft side. A control means for inputting the slip control speed from the control speed detecting means and performing slip control for bringing the lock-up clutch into a slip state by the engine speed and the slip control speed when a predetermined deceleration slip condition is satisfied. If the connected automatic transmission determines that sudden braking has occurred, With releasing the slip control by disengaging the clutch, the function of controlling so as to cut at least one clutch, since there is provided in addition to the control means,
This reduces the engagement between the engine and the input shaft during sudden braking, and can reliably prevent stall that occurs during sudden braking, which is practically advantageous. Further, if a detection signal from the vehicle speed sensor is input and a deceleration rate of the vehicle speed is calculated, and if this deceleration rate is equal to or more than a predetermined value, control means for judging that it is a time of a sudden brake is provided, It is possible to use the vehicle speed sensor already provided for the judgment, it is not necessary to newly provide an acceleration (G) sensor, there is no fear that the configuration is complicated, the cost can be kept low, and economical. Is advantageous.

[Brief description of the drawings]

FIG. 1 is a flowchart for control by a second control unit (TCU) of a stall prevention device for an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a stall prevention device of the automatic transmission.

FIG. 3 is a flowchart for control by a first control unit (ECU) of the stall prevention device of the automatic transmission.

4 shows a time chart of the stall prevention device of the automatic transmission, (a) is a time chart of vehicle speed, (b) is a time chart of a slip signal, and (c) is a slip (SL).
IP) oil pressure time chart, (d) is a time chart of neutral control oil pressure, and (e) is a time chart of engine speed.

FIGS. 5A and 5B show a time chart of another first embodiment of the present invention, wherein FIG. 5A is a time chart of a slip signal, and FIG.
Is the time chart of the slip (SLIP) hydraulic pressure, (c)
Is a time chart of the engine speed.

FIG. 6 is an enlarged view of a main part of a slip signal portion showing a time chart of another second embodiment of the present invention.

FIG. 7 is an enlarged view of a main part of a slip signal portion showing a time chart of another third embodiment of the present invention.

8A and 8B show a prior art of the present invention, wherein FIG. 8A is a time chart of vehicle speed, FIG. 8B is a time chart of slip signal, FIG. 8C is a time chart of slip (SLIP) oil pressure, and FIG. It is a time chart of a number.

[Explanation of symbols]

 2 Engine 4 Automatic Transmission 6 Torque Converter 8 Lockup Clutch 10 Engine Revolution Detecting Means 12 Slip Control Revolution Detecting Means 14 Input Shaft 16 Neutral (N) Control Clutch 18 Vehicle Speed Sensor 20 Lockup Control Solenoid 22 Neutral Control Solenoid 24 Control means 26 First control unit (ECU) 28 Second control unit (TCU) 30 Throttle opening sensor

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F16H 59:36 59:46 59:48

Claims (5)

[Claims] 1. A torque converter provided on an engine side, a lock-up clutch provided in the torque converter, an engine speed detecting means for detecting an engine speed, and a slip control speed for detecting a slip control speed. Engine speed detecting means, and at least one clutch provided between the engine side and the input shaft side, and an engine speed from the engine speed detecting means and a slip control from the slip control speed detecting means. An automatic transmission connected with control means for performing a slip control to put a lock-up clutch into a slip state by an engine speed and a slip control speed when a predetermined deceleration slip condition is satisfied by inputting a speed.
A function of disconnecting the lock-up clutch to release the slip control when it is determined that the vehicle is suddenly braked, and adding a function of controlling to disconnect at least one clutch to the control means is provided. A stall prevention device for an automatic transmission. 2. The control means includes a vehicle speed sensor for detecting a vehicle speed, and calculates a deceleration rate of the vehicle speed by inputting a detection signal from the vehicle speed sensor. The stall prevention device for an automatic transmission according to claim 1, wherein it is determined that time is reached. 3. The automatic transmission according to claim 1, wherein the automatic transmission includes a lock-up clutch provided in a torque converter, and a neutral control clutch provided between the engine side and the input shaft side. Stall prevention device for transmission. 4. The control means repeats the slip control of the lock-up clutch and the release of the slip control for a predetermined time when it is determined that the emergency braking is being performed, and disconnects the lock-up clutch after a predetermined time elapses. The stall prevention device for an automatic transmission according to claim 1, further comprising a function of canceling the slip control and controlling to disconnect at least one clutch. 5. The control means turns on a slip control signal when the slip control of the lock-up clutch and the release of the slip control are repeated for a predetermined time at the time of sudden braking.
The stall prevention device for an automatic transmission according to claim 4, further comprising a function of controlling the operation time and the OFF operation time to change stepwise.