JPH06307528A - Engagement control of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent slipping of wheels by optimizing engagement speed. CONSTITUTION:The engagement controller of automatic transmission is provided with a behavior detection means (a) for detecting the behavior relating to traveling and driving of a vehicle and a road surface friction judgement means (b) for judging the friction coefficient of the running surface based on the signal from the behavior detection means (a). An engagement actuator (e), which carries out operation for engaging the friction factor (d) of an automatic transmission (c), and which can change the engagement velocity, and an engagement velocity control means (f), which determines the engagement velocity of the friction factor (d) based on the relationship between the road surface friction coefficient and the car speed when the road surface friction coefficient is judged as no more than a predetermined level at the time of speed change, and which controls the operation of the engagement actuator (e) based on the result, are also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of an automatic transmission mounted on a vehicle, and more particularly to control of engagement speed of friction elements.

[0002]

2. Description of the Related Art Conventionally, among devices for controlling the engagement speed of a friction element, a device for controlling the engagement speed of a friction element when an engine brake is actuated is disclosed in, for example, Japanese Patent Laid-Open No. 62-62.
A backup pressure control device for an automatic transmission described in Japanese Patent Publication No.-80338 is known. This conventional device is a means for detecting the vehicle speed at the time of selecting to the manual range in an automatic transmission that supplies backup pressure to a friction element that is engaged when selecting from the automatic range to the manual range. A means for controlling the backup pressure based on the detection signal from the vehicle speed detecting means, and supplying an optimal backup pressure in accordance with the vehicle speed at the time of selection to provide emergency backup due to excessive backup pressure that causes a shift shock. In this case, it is possible to prevent the engagement delay due to the insufficient backup pressure, which causes the insufficient engine braking force.

[0003]

However, in the above-mentioned conventional apparatus, the backup pressure, that is, the driving force for engaging the friction element is set only on the basis of the vehicle speed. When the back-up pressure is controlled to be high at a high vehicle speed and downshifting is performed when the wheels slip on a road surface with a low road surface friction coefficient such as an icy road, the engine braking force will be reduced. If it is high, the wheels may slip further, which may reduce the stability of the vehicle.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to optimize the engagement speed and prevent the wheel from slipping.

[0005]

In order to achieve the above object, an engagement control device for an automatic transmission according to the present invention relates to running and driving of a vehicle as shown in the claim correspondence diagram of FIG. The behavior detection means a for detecting the behavior, the road surface friction determination means b for determining the friction coefficient of the traveling road surface based on the signal from the behavior detection means a, and the friction element d of the automatic transmission c are engaged and driven. , An engagement actuator e capable of changing the engagement speed, and when the road surface friction coefficient is determined to be equal to or less than a predetermined value at the time of shifting, the engagement speed of the friction element d is determined based on the relationship between the road surface friction coefficient and the vehicle speed. The engagement speed control means f for controlling the drive of the engagement actuator e according to the result is provided.

It should be noted that, as part of the behavior detecting means a, an accelerator depression amount detecting means for detecting an accelerator depression amount, a vehicle speed detecting means for detecting a vehicle speed, and a selected position detection for detecting a selected position of the automatic transmission. Means is provided and the engagement speed control means f selects the selected position from the high gear to the low gear based on the input from the behavior detection means a and the accelerator depression amount is less than or equal to a predetermined value. When it is determined that the vehicle is operating, and at the same time, when the road surface friction coefficient is below a predetermined value, the higher the vehicle speed, the slower the engagement speed becomes. The drive of the engagement actuator e may be controlled so as to reduce the speed. Also,
The road surface friction determining means b may determine the rotational deceleration of the drive wheels of the vehicle when the engine brake is applied, and may determine that the road surface has a lower friction coefficient as the deceleration increases.

Further, the road surface friction judging means b may obtain the rotational speeds of the driving wheels and the non-driving wheels of the vehicle and judge that the road surface has a low friction as the speed difference between the two is large.

Further, a part of the behavior detecting means a is a vehicle body acceleration detecting means for detecting a behavior related to the longitudinal acceleration / deceleration of the vehicle body, and a wheel rotational speed detection for detecting a behavior related to the rotational speed of the driving wheels. Means for providing the actual vehicle body obtained based on the input from the vehicle body acceleration / deceleration detection means and the calculated acceleration / deceleration obtained by calculation based on the input from the wheel rotation speed detection means. The actual acceleration / deceleration, which is the acceleration / deceleration of, may be obtained, and it may be determined that the road surface has lower friction as the difference between the two is larger.

[0009]

In gear shifting, when the road surface friction determining means detects a road surface having a low friction coefficient equal to or lower than a predetermined value, the engagement speed control means determines the engagement speed of the friction element based on the road surface friction coefficient and the vehicle speed. , The drive of the engagement actuator is controlled based on the result. Therefore, at the time of engine braking or acceleration, it is possible to delay the engagement speed to cause slippage in the friction element and prevent slippage between the wheel and the road surface.

Further, in the apparatus according to the second aspect, when the select position of the automatic transmission is selected from the high gear to the low gear and the accelerator depression amount is less than a predetermined value, it is determined that the engine brake is operating. At this time, the control is performed such that the engagement speed becomes slower as the vehicle speed becomes higher, and further, when the vehicle speed is higher than a predetermined value, the engagement speed becomes slower as the road surface friction coefficient becomes lower. As a result, it is possible to prevent slippage between the wheel and the road surface during engine braking.

[0011]

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

FIG. 2 is a structural explanatory view showing the outline of the structure of an automatic transmission AT to which the engagement control device of the first embodiment of the present invention is applied, in which T / C is a torque converter and O / P. Is an oil pump, IN is an input shaft, B / B is a band brake, R / C is a reverse clutch, H / C is a high clutch, S _F is a front sun gear, P _F is a front pinion gear, and R _F is a front internal gear. C _F
Is a front carrier, S _R is a rear sun gear, P _R is a rear pinion gear, R _R is a rear internal gear, C _R is a rear carrier, F / C is a forward clutch, F / OC forward one-way clutch, O / C is an overrun clutch, L / OC is rowan way clutch, L & R / B
Is a low and reverse brake, PP is a parking pole, PG is a parking gear, and OUT is an output shaft. Since this configuration is the same as the conventional technique and is known, detailed description thereof will be omitted.

Each friction element B / of the above-mentioned automatic transmission AT
B, R / C, H / C, F / C, F / OC, O / C, L
& R / B are engaged with the combinations shown in the engagement operation table of Table 1 below to operate the other friction elements F / O.
Combined with C and L / OC operation, 4 forward speeds and 1 reverse speed
It is possible to obtain a high speed shift stage. In the figure, ○, ◎,
The symbols ●, △, × indicate the engaged state, respectively, but ◎ is engaged at an accelerator opening of 1/16 to obtain the engine braking action, ● is operated in an accelerated state, and △ is It is engaged but does not contribute to power transmission, and x indicates that it is engaged at an accelerator opening of 1/16 but does not contribute to engine braking. Also, * 1 is limited to power mode operation, * 2 does not fasten the brake band, * 3 does.

[0014]

[Table 1] The above-mentioned friction elements B / B, R / C, H / C, F / C, F
The operation of / OC, O / C, L & R / B is controlled by the operation of a control valve CV provided below the automatic transmission A / T shown in FIG. 3, and the operation of this control valve CV is controlled. For this purpose, a first shift solenoid 1, a second shift solenoid 2, an overrun clutch solenoid 3, a lockup solenoid 4, and a line pressure solenoid 5 are provided. The drive of these solenoids 1 to 5 is controlled by the A / T control unit 6. The signal to the line pressure solenoid 5 is output via the dropping register 7.

That is, the A / T control unit 6
Is a behavior detection means for detecting behaviors related to traveling and driving of the vehicle, and is an idle switch 8 for detecting full closing of the throttle valve, 1 / th of the throttle valve.
Full throttle switch 9 for detecting two or more openings, throttle sensor 10 for detecting throttle opening, engine rotation sensor 11 for detecting the number of revolutions of engine E, inhibitor switch 12 for detecting the position of a manual lever (not shown), automatic A temperature sensor 13 for detecting the oil temperature in the transmission A / T, a first vehicle speed sensor 14 provided on the output shaft OUT of the automatic transmission A / T for detecting the vehicle speed, and a spare first built-in meter (not shown). 2 vehicle speed sensor 15,
Manual power shift switch 1 provided in the passenger compartment
6, a kick-down switch 17 for detecting the fully open state of the accelerator pedal (not shown) is provided, and further, in the present embodiment, the drive wheel sensor 1 for detecting the rotational speed of the drive wheel (not shown).
8 are provided.

The first and second shift solenoids 1 and 2 are driven to select a speed change gear according to the running state of the vehicle. The overrun clutch 3
Is for controlling the engine braking effect in accordance with the running state of the vehicle. When OFF, line pressure is supplied to the overrun clutch O / C to engage and engine brake is applied, while when ON, the overrun clutch O / C is applied. The line pressure is not supplied, and the engine is not braked because the line is not engaged. The lockup solenoid 4 regulates the lockup pressure according to the traveling condition of the vehicle. The line pressure solenoid 5 regulates the discharge pressure of the oil pump O / P to a pressure according to the running of the vehicle. That is, normally, the duty ratio is set so as to form the optimum line pressure based on the output of the throttle sensor 10. Control (ON-OF
The ratio of ON time of F switching is controlled).

In this embodiment, when the engine brake is applied, the engagement pressure (line pressure) of the overrun clutch O / C is set according to the vehicle speed V and the road surface friction coefficient μ (hereinafter, the road surface friction coefficient is referred to as road surface μ). By controlling, the engagement speed of the overrun clutch O / C is made variable.
That is, FIG. 4 shows a rising characteristic of the engagement pressure P when the overrun clutch O / C is engaged. As shown by, the engagement pressure P rises quickly at the start of engagement, and thereafter, the engagement pressure P increases as the vehicle speed decreases. , And the rising at the beginning of engagement is very slow, as shown in
There are three characteristics: a characteristic that the engagement pressure increases as the vehicle speed decreases, and a characteristic that the start-up at the start of engagement is medium and the engagement pressure increases as the vehicle speed decreases, as shown in. is doing. Overrun clutch O /
The fastening pressure of C is adjusted by driving the line pressure solenoid 5, and the line pressure solenoid 5 corresponds to the engagement actuator in the claims.

Next, the control of the engagement speed (engagement pressure) of the overrun clutch O / C will be described with reference to the flowchart of FIG.

This control is started when the manual lever is selected from the D range to the 2nd speed or the 1st speed. In step S1, it is determined whether or not the selection shifts from the high gear to the low gear. It is a step of determining whether or not, the process proceeds to step S2 if YES, and proceeds to the next other flow if NO.

In step S2, it is determined whether the throttle opening θ is less than or equal to a predetermined value θ ₀ based on the output from the throttle sensor 10. If YES, the process proceeds to step S3, where N
O is the step to proceed to the normal flow. The predetermined value θ ₀ is set to a throttle opening degree (for example, 1/16 of full opening) at which a sufficient engine braking action is obtained in the selected low speed gear, and is a sufficiently small opening degree.

Step S3 is a step for calculating the acceleration / deceleration G of the drive wheel based on the output from the drive wheel sensor 18.

Step S4 is a step of judging the road surface friction coefficient μ based on the acceleration / deceleration G obtained in the previous step S3, that is, when the acceleration G shows a deceleration of a predetermined value or more, the road surface friction coefficient μ is determined. It is determined that the road surface has low μ (hereinafter referred to as low μ road), and μ = α is processed. Note that this α is a small value indicating a low μ road. Further, the portion that makes the determination in step S4 corresponds to the road surface friction determination means in the claims.

Step S5 is a step of calculating the vehicle speed V from the output of the first vehicle speed sensor 14.

In step S6, it is determined whether or not the road surface friction coefficient μ determined in step S4 is equal to or less than a predetermined value μ _{0. If} YES, the process proceeds to step S7, and if NO, step S8.
This predetermined value μ ₀ is a value larger than α, and therefore, when it is determined in step S4 that the road surface is a low μ road, the process proceeds to step S7, and otherwise. , And proceeds to step S8.

A step S7 decides whether or not the vehicle speed V is a predetermined value V ₀ or less, and if YES, the process advances to a step S9,
This is the step that proceeds to step S10 if NO. The predetermined value V ₀ is a value for determining whether or not the vehicle is traveling at high speed, and is set to a value in the range of 30 to 40 Km / h, for example.

In step S8, the same judgment is made and YES.
Then, the process proceeds to step S9, and if NO, the process proceeds to step S11.

In step S9, the characteristic of FIG. 4 is selected, and the drive control of the line pressure solenoid 5 is performed based on this characteristic, that is, the overrun clutch O / C.
Is a step of performing drive control so as to increase the engagement speed at the start of engagement and thereafter increase as the vehicle speed V decreases. Incidentally, this characteristic is selected when the vehicle speed is low on a low μ road or low on a high μ road.

In step S10, the characteristic of FIG. 4 is selected, and the drive control of the line pressure solenoid 5 is performed based on this characteristic, that is, the overrun clutch O / C.
Is a step in which drive control is performed so that the engagement speed is very slow at the start of the engagement and thereafter increases as the vehicle speed V decreases. By the way, this characteristic is selected in the case of a low μ road and a high vehicle speed.

In step S11, the characteristic of FIG. 4 is selected, and the drive control of the line pressure solenoid 5 is performed based on this characteristic, that is, the overrun clutch O / C.
Is a step of performing drive control so that the engagement speed is medium when the engagement is started, and thereafter increases as the vehicle speed V decreases. By the way, this characteristic is selected in the case of a high μ road and a high vehicle speed. Step S5 described above
The part that performs the determination and processing from S11 to S11 corresponds to the engagement speed control means in the claims.

Therefore, when the engine lever is operated by operating the manual lever, when the vehicle speed V is lower than the predetermined value V ₀ , regardless of the road surface friction coefficient μ,
Line pressure control is performed based on the characteristics of FIG. 4, and the engagement speed of the overrun clutch O / C is controlled faster. In this case, since the vehicle speed V is low even when traveling on a low μ road,
The wheels do not slip. Further, when the vehicle speed V is higher than the predetermined value V ₀ , the line pressure control is performed on the high μ road based on the characteristic of FIG. 4 on the high μ road, and the overrun clutch is applied at an engagement speed slower than that at the low speed running. Engage O / C. As described above, when the vehicle runs on a high μ road at high speed, the slipping of the wheels is not a problem even if the engagement speed is not slowed down, but the engagement speed is slightly delayed in order to alleviate the shift shock. On the other hand, when the vehicle runs on a low μ road at high speed, the line pressure control is performed based on the characteristics shown in FIG. 4, and the engagement speed of the overrun clutch O / C is made slower than when the vehicle runs on a high μ road at high speed. Since the engagement speed is slowed in this way, it is possible to prevent the wheels from slipping even on a low μ road and ensure traveling stability.

Next, a second embodiment of the present invention will be described.

FIG. 6 is a block diagram showing the main part of the second embodiment device. In this embodiment, in addition to the drive wheel sensor 18, a driven wheel sensor 19 for detecting the rotational speed of the driven wheel is provided. This is an example in which a road surface μ determination different from that of the first embodiment is performed. Further, in the figure, reference numeral 20 denotes a slip amount calculation unit that calculates a slip amount based on signals from the driving wheel sensor 18 and the driven wheel sensor 19, and 21 denotes a slip amount calculation unit 20.
A road surface friction determining unit that determines the road surface μ based on the calculation result of the above, a select position determining unit that determines a select position based on a signal from the inhibitor switch 12, and a select position determining unit 23
Is a vehicle speed calculation unit that calculates a vehicle speed V based on a signal from the first vehicle speed sensor 14, 24 is an accelerator depression amount calculation unit that calculates an accelerator depression amount based on a signal from the throttle sensor 10, and 25 is each determination unit 21. , 22 and arithmetic unit 2
3 and 24 are engagement speed switching determination units that determine the engagement speed based on the signals from the ATs of the first embodiment.
The part which performs signal processing inside the control unit 6 is shown.

The operation of the above configuration will be described with reference to the flowchart of FIG. The steps having the same contents as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In step S21, the slip amount calculator 20
In the case of the present embodiment, the drive wheel rotational speed N ₁ obtained from the output of the drive wheel sensor 18 and the driven wheel rotational speed N obtained from the output of the driven wheel sensor 19 are determined. _This is the step of calculating the slip amount L based on the difference from ₂ (| L | = | N ₁ −N ₂ |). Steps S22, S23, S24 are steps for determining the road surface μ in the road surface friction determining unit 21, and
In S22, it is determined whether or not the slip amount L is equal to or more than the predetermined value L ₀ , and if YES, the process proceeds to step S23, and the road surface μ is processed as α (where α is a low value and a low μ road No.), the process proceeds to step S24 with NO to process the road surface μ as β (note that β is a high value and corresponds to a high μ road). To).

In steps S6 to S11, the engagement speed switching calculator 25 selects the line pressure characteristic in accordance with the road surface μ as in the first embodiment. In step S6, the road surface μ has a predetermined value μ _0. It is determined whether or not the following is satisfied. The predetermined value μ ₀ has a relation of β> predetermined value μ ₀ > α.

Based on the above construction, the overrun clutch O / C during high speed running on a low μ road, as in the first embodiment.
It is possible to prevent the wheels from slipping by slowing the engagement speed of.

Next, a third embodiment of the present invention will be described.

FIG. 8 is a block diagram showing the main part of the third embodiment device. In this embodiment, an acceleration / deceleration sensor 26 for detecting the longitudinal acceleration / deceleration of the vehicle body is provided instead of the drive wheel sensor 18. This is an example in which a road surface μ determination different from that of the first embodiment is performed. Further, reference numeral 27 in the figure is an acceleration / deceleration calculation unit. The same components as those in the first or second embodiment are designated by the same reference numerals and the description thereof will be omitted.

The operation of the above configuration will be described with reference to the flowchart of FIG. The steps having the same contents as those in the first or second embodiment are designated by the same reference numerals and the description thereof will be omitted.

In step S31, the acceleration / deceleration calculation unit 27 obtains the engine load based on the selected position, the vehicle speed V, and the accelerator pedal depression amount, and the calculated acceleration / deceleration, which is the acceleration / deceleration of the vehicle body calculated from the engine load. This is a step of calculating G _A.

Steps S32, S33, S23, S24
Is a step for determining the road surface μ, and in step S32, from the calculated acceleration / deceleration G _A obtained from the acceleration / deceleration calculation unit 27 and the actual acceleration / deceleration G _T obtained from the acceleration / deceleration sensor 26, Obtain the slip degree L _B (| L _B ｜
_{= | G A -G T |)} . In the next step S33, it is determined whether the slip degree L _B is equal to or more than a predetermined value L _B0 ,
If YES, the process proceeds to step S23, where the road surface μ is processed as α, and if NO, the process proceeds to step S24 where the road surface μ is processed as β (note that α, β and the predetermined value μ _{0 in} step S6 are , The same values as in the first and second embodiments).

Based on the above construction, the overrun clutch O / C during high speed running on a low μ road, as in the first embodiment.
It is possible to prevent the wheels from slipping by slowing the engagement speed of.

Although the embodiment has been described above, the specific structure is not limited to this embodiment, and the present invention includes a design change and the like within a range not departing from the gist of the invention. For example, in the embodiment, the control for preventing wheel slippage during engine braking has been described, but the present invention can also be applied to control for preventing wheel slippage during start or acceleration. In this case, for example, in steps S21 to S24 of the second embodiment, the road surface μ is obtained from the slip amount L. For example, if the throttle opening θ is a predetermined value or more and the road surface μ is a predetermined value or less, the line pressure Can be implemented by slowing the rise of the friction element and controlling the engagement speed of the friction element to be engaged at that time.

[0044]

As described above, in the engagement control device for an automatic transmission according to the present invention, when it is determined that the road surface friction coefficient is less than or equal to a predetermined value at the time of gear shifting, it is based on the relationship between the road surface friction coefficient and the vehicle speed. The engaging speed of the friction element is determined according to the result, and the engaging speed control means for controlling the drive of the engaging actuator is provided according to the result, so that gear shifting is performed while traveling on a road surface having a low friction coefficient. Occasionally, the engagement speed can be delayed to cause slippage in the friction element to prevent slippage between the wheel and the road surface, which has the effect of improving running stability. .

According to the second aspect of the present invention, it is determined that the engine braking is in operation because the select position is selected from the high gear to the low gear and the accelerator depression amount is less than a predetermined value. At the same time, when it is determined that the road surface friction coefficient is less than or equal to a predetermined value, the engagement speed is reduced as the vehicle speed increases, and when the vehicle speed is more than the predetermined value, the engagement speed is decreased as the road surface friction coefficient decreases. Since the drive is controlled, it is possible to prevent the wheels from slipping and to improve the running stability, especially when the engine brake is applied.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing an engagement control device for an automatic transmission according to the present invention.

FIG. 2 is a structural explanatory view showing the structure of an automatic transmission to which the engagement control device for an automatic transmission according to the first embodiment of the present invention is applied.

FIG. 3 is a configuration explanatory view showing a configuration related to a portion for controlling the first embodiment device.

FIG. 4 is a line pressure characteristic diagram of the first embodiment device.

FIG. 5 is a flowchart showing the control flow of the first embodiment device.

FIG. 6 is a block diagram showing an engagement control device for an automatic transmission according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing the control flow of the second embodiment device.

FIG. 8 is a block diagram showing an engagement control device for an automatic transmission according to a third embodiment of the present invention.

FIG. 9 is a flowchart showing the control flow of the third embodiment device.

[Explanation of symbols]

 a behavior detection means b road surface friction determination means c automatic transmission d friction element e engagement actuator f engagement speed control means

Claims (5)

[Claims] 1. A behavior detecting means for detecting behavior related to traveling and driving of a vehicle, a road surface friction determining means for determining a friction coefficient of a traveling road surface based on a signal from the behavior detecting means, and a friction of an automatic transmission. When an engagement actuator that drives the elements to engage and that can change the engagement speed is selected, and when the road surface friction coefficient is determined to be below a predetermined value when shifting,
And an engagement speed control means for determining the engagement speed of the friction element based on the relationship between the road surface friction coefficient and the vehicle speed, and controlling the drive of the engagement actuator according to the result. Engagement control device for automatic transmission. 2. The behavior detecting means includes an accelerator depression amount detecting means for detecting an accelerator depression amount, a vehicle speed detecting means for detecting a vehicle speed, and a select position detecting means for detecting a select position of an automatic transmission. However, the engagement speed control means is based on the input from the behavior detection means, when the select position is selected from high gear to low gear and the accelerator depression amount is less than a predetermined value, so that it is during engine braking. At the same time, if it is determined that the road surface friction coefficient is less than or equal to a predetermined value, the higher the vehicle speed, the slower the engagement speed, and if the vehicle speed is a predetermined value or more, the lower the road surface friction coefficient, the slower the engagement speed. The engagement control device for an automatic transmission according to claim 1, wherein the engagement control device controls the drive of the engagement actuator. 3. The road surface friction determining means determines the rotational deceleration of the drive wheels of the vehicle when the engine brake is applied, and determines that the road surface has a lower friction coefficient as the deceleration increases. The engagement control device for an automatic transmission according to claim 2. 4. The road surface friction determining means obtains rotational speeds of a driving wheel and a non-driving wheel of a vehicle, and determines that the road surface has low friction as the speed difference between the two is large. The engagement control device for an automatic transmission according to claim 1 or 2. 5. The behavior detecting means includes a vehicle body acceleration detecting means for detecting a behavior relating to a longitudinal acceleration / deceleration of a vehicle body, and a wheel rotation speed detecting means for detecting a behavior relating to a rotation speed of a drive wheel. However, the road surface friction determination means uses the calculated acceleration / deceleration obtained by calculation based on the input from the wheel rotation speed detection means and the actual acceleration / deceleration of the vehicle body obtained based on the input from the vehicle body acceleration / deceleration detection means. The engagement control device for an automatic transmission according to claim 1 or 2, wherein a certain actual acceleration / deceleration is obtained, and it is determined that the road surface has lower friction as the difference between the two is larger.