JP3477925B2 - Anti-creep control system for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a creep prevention control device for an automatic transmission, and more specifically, it selectively controls creep prevention and creep prevention inhibition functions in accordance with the temperature of hydraulic oil when the automatic transmission is in a running range. The present invention relates to a creep prevention control device for an automatic transmission.

[0002]

2. Description of the Related Art Conventionally, as a creep prevention control device for an automatic transmission, a device disclosed in, for example, Japanese Patent Application Laid-Open No. 58-202116 is known. The configuration of the operation control device for the automatic transmission with the creep prevention mechanism of the invention disclosed in this publication will be briefly described.

As shown in FIG. 8, a conventional device of this type disclosed in Japanese Patent Laid-Open No. 58-202116 discloses the output torque of an engine E as a hydraulic torque converter T and an auxiliary transmission M. In the middle of the transmission system that is transmitted to the drive wheels W, W ′ via the engine, a creep prevention mechanism that detects it during idle operation of the engine E and shuts off the transmission system is installed, and it is used during warm-up operation of the engine. It is characterized in that a creep prevention releasing means for detecting the occurrence of the above and stopping the operation of the creep prevention mechanism is provided.

[0004]

As described above, in the conventional creep prevention control device, the creep prevention is prohibited when the engine is warmed up in order to promote warming up of the engine body. It was

However, even if the creep prevention control device is operated after the engine is warmed up, the operating oil temperature of the automatic transmission (in particular, the lubricating oil temperature supplied to the automatic transmission power train).
As is clear from the characteristic diagram of FIG. 9, when the vehicle temperature is low, the friction of the automatic transmission main body (due to the drag of the friction element or the like) increases when the vehicle is stopped. Then, FIG.
As shown in the characteristic diagram of No. 2, the torque converter is operated in the region A in which the speed ratio is smaller than when the transmission fluid temperature is high,
Since the torque capacity coefficient becomes the largest, the engine load becomes larger than in the creep prevention prohibited state (speed ratio e = 0). Note that, in FIG. 10, the reference character A indicates an operating state at low temperature, B indicates an operating state at high temperature, and C indicates respective characteristic portions in the creep prevention prohibited state.

More specifically, when the engine torque during creep prevention operation is T _E , the transmission input torque is T _τ , and the engine speed is N _E at low temperature, T _E = τ _L × N _E ² ... (1) T _τ = τ _L × T _E , (friction torque of automatic transmission main body). When the engine torque during creep prevention operation is T _E and the transmission input torque is T _τ at high temperature, T _E = τ _H × N _E ² (2) T _τ = 1. From 0 × T _E , (friction torque of automatic transmission main body) τ _L > τ _H , equation (2) <equation (1) is obtained. by the way,
The engine torque when creep prevention is prohibited (e = 0) is T _E
Then, T _E = τ _S × N _E ² (3)

From equations (1), (3), and τ _S <τ _L , equation (3) <(1), and the engine load is smaller when creep prevention is prohibited at low temperatures. Therefore, when the automatic transmission hydraulic oil temperature is low, the idle fuel consumption and the idle vibration become larger than in the creep prevention prohibited state (speed ratio e = 0), and there is a problem that it defeats the original purpose.

The object of the present invention has been made by paying attention to such a conventional problem, and a means for detecting a hydraulic oil temperature of an automatic transmission is provided to prohibit a creep preventing operation according to the hydraulic oil temperature. Alternatively, when the speed ratio of the torque converter is less than or equal to a predetermined value during the creep prevention operation, the creep prevention control device for the automatic transmission that improves the fuel efficiency during idle and reduces the vibration during idle by prohibiting the creep prevention operation is provided. To provide.

[0009]

SUMMARY OF THE INVENTION The present invention is a creep prevention control for an automatic transmission, which is configured as follows in order to solve the above-mentioned technical problems .

That is, the first aspect of the present invention
Selector lever operated by torque converter and driver
When the driving range is selected by
Via an automatic transmission with friction elements to enable transmission
While transmitting to the drive wheels, when the vehicle is stopped
The friction element is
The transmission of the engine output to the drive shaft is regulated by removing
Anti-creep control for automatic transmission to prevent creep
In the device, the input shaft and output shaft of the torque converter
It is equipped with rotation speed detection means to detect the rotation speed of
During the loop prevention operation, the rotation speed detection means
Input shaft rotation speed of the torque converter and torque converter
The output shaft rotation speed is detected, and the torque converter
Difference in speed between the input and output shafts or speed ratio, that is, output shaft rotation speed
Degree / input rotation speed is calculated, and the difference between both rotations is more than a specified value or
When the speed ratio is less than the specified value, the friction element is completely connected.
To perform the creep prevention prohibition operation.
Is characterized by.

Further , the automatic transmission according to the second aspect of the present invention
The leap prevention controller converts the engine output to torque converter.
And a select lever operated by the driver
When the gear is selected, it can be engaged to transmit power.
Transmission to drive wheels via automatic transmission with friction element
On the other hand, the driving range is selected when the vehicle is stopped
Nevertheless, by releasing the fastening of the friction element
The transmission of engine output to the drive shaft is restricted to prevent creep.
In the creep prevention control device of the automatic transmission to prevent
Hydraulic oil temperature detection for detecting the hydraulic oil temperature of the automatic transmission
Means, and based on the detection signal of the hydraulic oil temperature detection means
When the hydraulic oil temperature of the automatic transmission is low, the creep
Creep prevention that allows creep by deactivating the preventive action
Stop prohibition means, input shaft and output shaft of the torque converter
Rotation speed detection means for detecting the rotation speed of
During the leap prevention operation, the rotation speed detection means
Torque converter input shaft speed and torque converter
The output shaft rotation speed of the
Is both rotations of the input / output shaft in the torque converter
Calculate difference or speed ratio, that is, output shaft rotation speed / input rotation speed
However, if the rotation speed difference is greater than or equal to the specified value or the speed ratio is less than or equal to the specified value
The friction element completely regardless of the hydraulic oil temperature.
Characterized by performing a creep prevention prohibition operation by combining them
And

[0012]

According to the creep preventive control device for the automatic transmission of the first aspect of the present invention, as a basic operation, when the driver stops the vehicle with the sect lever in the travel range, all friction of the automatic transmission is reduced. The element is released to prevent the creep of the automatic transmission in which the transmission of the engine output to the drive wheels is restricted.

At this time, the torque control is performed during the creep prevention operation.
Calculate the input rotation speed and output rotation speed of the barter to obtain the rotation difference.
Is greater than a specified value or the speed ratio is less than a specified value, the friction element
Conclude In other words, the input rotation of the torque converter
The rotation difference between the speed and the output rotation speed is greater than a specified value or the speed ratio
Is less than a predetermined value, the friction of the automatic transmission body
As it gets bigger and the engine load also gets bigger,
In such a case, the creep prevention control is controlled to be prohibited.

According to the creep preventive control device for the automatic transmission of the second invention , the driver operates as a basic operation.
Move the vehicle with the select lever in the driving range.
When stopped, all friction elements of the automatic transmission are released.
This restricts the transmission of engine output to the drive wheels.
The creep of the automatic transmission is prevented.

At that time, the operating oil temperature of the automatic transmission is detected.
Based on the detection signal from the hydraulic oil temperature detection means,
When the temperature is high, the friction of the main body of the automatic transmission increases.
Engine load is higher than that in the creep prevention prohibited state.
Therefore, the creep prevention prohibition means is a creep prevention means.
Deactivate and control to allow creep. Moreover, creep prevention inhibiting means, the input rotation speed and an output rotational speed by the operated rotational difference is greater than a predetermined value or speed ratio of the torque converter fastening a friction element when the predetermined value or less during operation of the anti-creep . In other words, even if the rotation difference between the input rotation speed and the output rotation speed of the torque converter is greater than or equal to a predetermined value or the speed ratio is less than or equal to a predetermined value, the friction of the automatic transmission body increases and the engine load also increases. Even in such a case, the creep prevention control is controlled to be prohibited.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The creep prevention control device for an automatic transmission according to the present invention will be described below in more detail with reference to the embodiments shown in the drawings. FIG. 1 shows a creep prevention control device 10 for an automatic transmission according to an embodiment of the present invention. The creep prevention control device 10 is configured to include an engine 11, a torque converter (fluid coupling) 12 of an automatic transmission (AT), and a clutch 13 as a friction element that continues to be operated in a running range of the automatic transmission.

The power from the engine 11 is input to the torque converter 12 via the crankshaft 11a, and the torque converter 12 inputs the engine power to the clutch 13 via the output shaft 12a. Clutch 13
Is a clutch housing 13a, a drive plate 13b drivingly connected to the clutch housing 13a, and a driven plate 13c drivingly connected to an output shaft 14 of the automatic transmission.
When the hydraulic pressure is supplied to the chamber 13e, the clutch 13 is composed of a clutch pack and a clutch piston 13d.
Is capable of operating to transmit the engine power reaching the shaft 12a to the output shaft 14 and to driving wheels (not shown) to drive the vehicle.

The chamber 13e is supplied with a clutch pressure P _C obtained by adjusting the original pressure (line pressure of the automatic transmission) P _L supplied in the running range of the automatic transmission by the control valve 15, and thereby the clutch pressure P _C is supplied. The operation of the clutch 13 is controlled. The control valve 15 includes a spool 15a, one end of which is in the chamber 15b,
The other end faces the chamber 15c, and the spool 15a is in the chamber 13c.
The circuit 16 from e is selectively communicated with a source pressure circuit 18 with a pulsation damping orifice 17 or a drain port 19.

The chamber 15b is connected to the circuit 16 by a circuit 21 with a pulsation damping orifice 20, and the chamber 15c is connected to a source pressure circuit 18 by a circuit 23 with an inlet orifice 22 and communicated with a drain orifice 24.

A solenoid valve 25 is provided in opposition to the drain orifice 24. This solenoid valve normally allows the plunger 25a to be in a free state to allow drainage from the drain orifice 24, and the plunger 25a when energized is moved to the left from the position shown in the drawing. The drain orifice 24 is closed. The solenoid valve 25 is duty-controlled by the control computer 26 to generate a control pressure P _S in the chamber 15c according to the duty ratio.

The control pressure P _S acts on the spool 15a so as to oppose the clutch pressure P _C reaching the chamber 15b via the circuit 21, and when P _S > P _C , the spool 15a moves to the left in the drawing to move to the clutch pressure P _{C. C} is increased by supplementing the original pressure P _L , and when P _S <P _C , the spool 15a moves to the right in the drawing to reduce the clutch pressure P _C from the port 19 by draining. Thus, the control valve 15
Has the effect of controlling the clutch pressure P _C to the same value as the control pressure P _S, and the clutch pressure P _C can be changed by changing the control pressure P _S.

The energization of the solenoid valve 25 is duty-controlled so that it is carried out from the control computer 26 during the pulse width (ON time) as shown in the waveforms (a) and (b) of FIG. As shown in the waveform (b) of FIG. 2, when the duty (%) is large, the solenoid valve 25 closes the drain orifice 24 for a long time, so that the control pressure P _S is as shown in FIG.
As shown in (3), it increases as the duty (%) increases, and finally becomes the same value as the original pressure P _L.

On the contrary, when the duty (%) is small as shown in the waveform (a) of FIG. 2, the solenoid valve 25 closes the drain orifice 24 for a short time, so that the control pressure P _S is as shown in FIG. The duty ratio (%) decreases as the duty (%) decreases, and finally becomes a constant minimum value determined by the difference in the opening areas of the orifices 22 and 24.

By the way, since the control valve 15 sets the clutch pressure P _C to the same value as the control pressure P _S as described above, the clutch pressure PC also changes with the characteristic as shown in FIG. 3 according to the duty (%).

A computer 26 for duty-controlling the solenoid valve 25 supplies a signal from a temperature sensor 32 for detecting the temperature T of the AT hydraulic oil, a signal from an engine speed sensor 27 for detecting an engine speed N _E , and a torque. The signal from the torque converter output speed sensor 28 for detecting the converter output speed N _T , the signal from the transmission output speed sensor 29 for detecting the transmission output speed N _O , and the signal when the accelerator pedal is released are turned on. The signal I from the idle switch 30 and the signal R from the inhibitor switch 31 that detects the travel range of the automatic transmission in which the clutch 13 should continue to operate are input.

The computer 26 repeatedly executes the control program shown in the flow chart of FIG. 4 based on these input information to control the duty of the solenoid valve 25. At the start of the program, the solenoid valve 2 is first operated at step 40.
The output duty etc. to 5 is initialized (initial value setting). In the next step 41, the engine speed N _E ,
The torque converter output speed N _T and the transmission output speed N _O are read respectively, and further, the temperature T of the AT hydraulic oil, the idle signal I, and the selected range signal R are read.

In the next step 42, it is judged from the signal R whether or not it is in the running range in which the clutch 13 should be continuously operated. If not, the control is returned to step 41 and the above-mentioned loop is repeated. Step 43
Proceed to. In step 43, AT hydraulic fluid temperature to determine whether more than a predetermined value T _C, if more than a predetermined value T _C proceeds to step 44, the output duty 10 if less than a predetermined value T _C
The clutch 13 is completely engaged with 0%.

In step 44, the transmission output speed N _O
Is 0 or not, that is, whether or not the vehicle is stopped at zero vehicle speed,
If the vehicle is traveling without being stopped, the output duty is set to 100% in step 45, the control is returned to step 41, and the above-described loop is repeated. This output duty of 100% is shown in FIG.
As can be seen from the above, the clutch pressure P _C is set to the maximum value, and the clutch 13 actuated by this is completely engaged. Therefore, the power from the engine 11 is applied to the torque converter 12.
And, it is transmitted to the shaft 14 through the clutch 13 to enable the traveling.

If it is determined in step 44 that the vehicle is stopped, it is determined in step 46 whether or not the accelerator pedal is released from the idle signal I, and the vehicle is not started, and if the accelerator pedal is depressed, the start control is performed in step 47. After that, the control is returned to step 41 and the above-mentioned loop is repeated. The start control is performed by gradually increasing the clutch pressure P _C by gradually increasing the output duty, as is apparent from FIG.
Engage and advance the clutch 13 to prevent shock.
The vehicle is started without shock.

When the vehicle is stopped without a starting position, which is determined to be accelerator pedal release in step 46, in step 48,
Perform normal creep prevention control. After execution, the process returns to step 41 and the above loop is repeated. Here, before roughly explaining the normal creep prevention control, first, the difference between the engine speed (torque converter input speed) N _E and the torque converter output speed N _T (torque converter slip amount) N _E − N _T (which allows the transmission output torque to be inferred) is determined, and this is the upper limit of the transmission output torque that is allowed for creep prevention (it depends on the load, road gradient, etc.)
The output duty to the solenoid valve 25 (slip coupling force of the clutch 13) is PI-calculated so that the target torque converter slip amount corresponding to is maintained.

Thus, the clutch 13 can be prevented from slipping by slipping so that the transmission output torque (creep torque) is kept at the upper limit value of the transmission output torque which is allowable for creep prevention. Further, at the time of starting after such creep prevention, the engagement progress of the clutch 13, which is executed as described above in step 47, is promptly performed because it is not from the clutch disengaged state but from the slip coupling state. You can eliminate the delay.

FIG. 5 shows an automatic transmission in a creep prevention control system for an automatic transmission according to a second embodiment of the present invention. In the second embodiment, the AT lubricating oil supply passage 3 for communicating the AT hydraulic oil temperature sensor 32 provided in the first embodiment shown in FIG. 1 with the shaft center of the shaft is provided.
It is arranged at an arbitrary position (non-rotating portion) of No. 3.

The conventional temperature sensor is installed in the vicinity of the oil pan OP as indicated by the symbol TS in FIG. The temperature of the oil near the oil pan OP and the friction of the AT body (drag of the friction element) greatly influence and have a high correlation. It is very different from the core lubrication temperature.

In the present invention, since it is necessary to activate the creep prevention only when the friction of the AT body becomes sufficiently small, it is necessary to directly measure the lubricating oil temperature of the power train, which has a very high correlation with the friction of the AT body. is there. At a temperature near the oil pan as in the conventional case, there is a problem that a sufficiently effective creep prevention control cannot be realized.

Next, FIG. 6 shows a creep prevention control system for an automatic transmission according to a third embodiment of the present invention.
In the creep prevention control device for an automatic transmission according to the third embodiment, the temperature sensor 32 is removed from the creep prevention control device 10 according to the first embodiment shown in FIG. 1, and other configurations are the same. is there.

In the third embodiment, the speed ratio N _T / N _E of the torque converter is calculated during the creep prevention control operation,
If the speed ratio is equal to or smaller than a predetermined value e ₀ (e ₀ = 0.9th place, for example), the friction of the AT body increases and the engine load also increases (see FIG. 10), so the creep prevention control is prohibited. Or the input rotation difference of the torque converter ΔN
= N _E −N _T is calculated, and if the rotation difference is equal to or greater than the predetermined value ΔN _{O, the} creep prevention control is prohibited.

The operation of the creep preventing control system for the automatic transmission according to the third embodiment will be described with reference to the flow chart shown in FIG. In step 50, the creep prevention control is activated. Then, in step 51, the speed ratio N _T / N _E of the torque converter during the creep prevention operation is calculated. Then, in step 52, N _T / N _E > e
_{If 0} (≈0.9), it is determined that the AT friction is small, and the creep prevention control is continued. If N _T / N _E ≦ e ₀ , it is determined that the friction of the AT is large, and in step 53, the creep prevention FLG = 0 is set, and the duty is set to 100% to prohibit the creep prevention.
Here, by setting FLG = 0, the prohibition of creep prevention is continued even if the creep prevention operation condition is satisfied in step 54. In step 55 or step 56, if the creep prevention operating condition such as the traveling or starting control is canceled even once, FLG = 1, and if the creep prevention operating condition is satisfied next, the creep prevention control operates.

In addition to the above embodiment, as a method of indirectly estimating the AT hydraulic oil temperature, not directly, it is time-integrated (∫N _O dt) from the transmission output speed N _O (equivalent to vehicle speed). Estimate the distance traveled, and from the time since the engine was started, the outside air temperature signal used by the air conditioner, etc.
There is also a method of estimating the T hydraulic oil temperature and prohibiting creep prevention at a predetermined temperature or lower.

[0039]

As described in the foregoing, according to the creep prevention control device for an automatic transmission in the first aspect of the present invention, Cree
The anti-slip control means controls the torque control during creep-prevention operation.
Calculate the input rotation speed and output rotation speed of the barter to obtain the rotation difference.
If the gear ratio is greater than or equal to a specified value or the speed ratio is less than or equal to a specified value, automatic gear shifting
The friction of the main body is large and the engine load is large.
Control so that the friction element is fastened.
As a result, it is possible to stably reduce idle fuel consumption and idle vibration.

Further, according to the creep preventive control device for the automatic transmission in the second aspect of the invention, the temperature of the hydraulic oil of the AT is detected.
Depending on the hydraulic oil temperature,
Since the control is to switch the operation, it depends on the AT oil temperature.
Regardless of the size of the AT friction that affects
The engine load is always the minimum. Furthermore, the movement of creep prevention
Input rotation speed and output rotation speed of the torque converter during operation
Is calculated and the rotation difference is greater than or equal to the specified value or the speed ratio is less than or equal to the specified value
In the case of
Even in such a case, the friction of the automatic transmission body
The larger the engine load, the more
Disable the anti-pull operation. Therefore, stable idle combustion
Cost and idle vibration can be reduced.

[0041]

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing a creep prevention control device for an automatic transmission according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram showing a pulse waveform from a control computer that constitutes a creep prevention control device for an automatic transmission according to a first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing control pressure and clutch pressure during duty control of a solenoid valve by a control computer that constitutes a creep prevention control device for an automatic transmission according to a first embodiment of the present invention.

FIG. 4 is a flowchart illustrating the operation of the creep prevention control system for an automatic transmission according to the first embodiment of the present invention.

FIG. 5 is a structural explanatory view schematically showing an automatic transmission equipped with an AT lubricating oil temperature sensor in a creep prevention control device for an automatic transmission according to a second embodiment of the present invention.

FIG. 6 is a configuration explanatory view similar to FIG. 1, showing a creep prevention control device for an automatic transmission according to a third embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation of a creep prevention control device for an automatic transmission according to a third embodiment of the present invention.

FIG. 8 is a structural explanatory view schematically showing a conventional creep prevention control device for an automatic transmission.

FIG. 9 is a characteristic diagram showing a relationship (corresponding to a non-driving range) between a hydraulic oil temperature and a friction of a transmission main body in an automatic transmission.

FIG. 10 is a characteristic diagram showing a relationship between a hydraulic oil temperature and an engine load in an automatic transmission.

[Explanation of symbols] 10 Creep prevention control device for automatic transmission 11 engine 12 Torque converter 13 Automatic transmission 14 Output shaft 15 control valve 25 solenoid valve 26 Control computer 27 Engine speed sensor 28 Torque converter output speed sensor 29 Automatic transmission output speed sensor 32 Automatic transmission hydraulic oil temperature sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 45/00 F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63 / 48 F16D 25/00-39/00 F16D 48/00-48/12

Claims (2)

(57) [Claims] 1. An engine output is transmitted to a drive wheel through an automatic transmission having a torque converter and a friction element that is engaged to transmit power when a travel range is selected by a select lever operated by a driver. On the other hand, when the vehicle is stopped, the creep of the automatic transmission that prevents the creep by restricting the transmission of the engine output to the drive shaft by releasing the engagement of the friction element despite the selection of the running range In the prevention control device, a rotation speed detecting means for detecting rotation speeds of the input shaft and the output shaft of the torque converter is provided, and during the creep preventing operation, the rotation speed detecting means detects the input shaft rotation speed and torque of the torque converter. The output shaft rotation speed of the converter is detected, and the rotation difference or speed ratio between the input and output shafts of the torque converter, that is, The force shaft rotation speed / input rotation speed is calculated, and when the rotation difference between both is greater than or equal to a predetermined value or the speed ratio is less than or equal to a predetermined value, the friction elements are completely coupled to perform the creep prevention prohibiting operation. Creep prevention control device for automatic transmission. 2. The engine output is controlled by a torque converter and a drive.
Select the driving range with the select lever operated by Iba
A friction element that can be engaged to transmit power when
Transmission to the drive wheels via an automatic transmission having
On the other hand, even if the driving range is selected when the vehicle is stopped
Even if the friction element is unfastened,
Prevents creep by limiting the transmission of gin output to the drive shaft
In a creep prevention control device for an automatic transmission, the operating oil temperature detection for detecting the operating oil temperature of the automatic transmission is performed.
Means, and based on the detection signal of the hydraulic oil temperature detection means
When the hydraulic oil temperature of the automatic transmission is low, the creep
Creep prevention that allows creep by deactivating the preventive action
Stop prohibition means, input shaft and output shaft of the torque converter
Rotation speed detection means for detecting the rotation speed of
During the leap prevention operation, the rotation speed detection means
Torque converter input shaft speed and torque converter
The output shaft rotation speed of the
Is both rotations of the input / output shaft in the torque converter
Calculate difference or speed ratio, that is, output shaft rotation speed / input rotation speed
However, if the rotation speed difference is greater than or equal to the specified value or the speed ratio is less than or equal to the specified value
The friction element completely regardless of the hydraulic oil temperature.
Characterized by performing a creep prevention prohibition operation by combining them
An automatic transmission creep prevention control device.