JPH02212668A - Slip control device for fluid joint - Google Patents

Abstract

PURPOSE:To produce an acceleration feeling even during the change of a running load by providing a means to detect a running load and a means to receive an output from the detecting means to correct the engaging force of a lockup clutch in response to a detected running load. CONSTITUTION:In a step S2, a car speed V, a throttle opening theta, the number NE of revolutions of an engine, the number NT of revolutions of a turbine, and a gear shifting step position G are read from respective sensors to compute a slip ratio NS. A car weight W and a car body gradient alpha are read from respective sensors, and respective correction factors Cw and Ca are read from a map to compute a target slip amount No. A deviation N between a present actual slip amount NS and a target slip ratio No is determined, and when it is decided that a present operation area is in a slip control area, control parameters A and B are decided, a feedback amount U is computed, and a duty correction amount dF responding to the feedback amount is determined from a map to determine a present duty ratio D. Namely, when a running load is increased, a slip amount is increased.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a slip control device for a fluid coupling equipped with a lock-up clutch mechanism used, for example, in automatic transmissions for automobiles. The present invention relates to a slip control device that controls a slip state by controlling fastening force.

(Prior Art) In fluid couplings (hereinafter referred to as torque converters) used in automatic transmissions for automobiles, in order to reduce the deterioration of engine fuel efficiency caused by so-called slippage of the torque converter, torque is increased. In a predetermined operating range in which the torque converter does not require action or absorption of shift shock, a lock-up clutch may be provided to directly connect the input member and output member of the torque converter.

By the way, if this lock-up clutch is engaged and the output member of the I-lux converter is directly connected, engine vibrations will be directly transmitted to the transmission, especially in the low engine rotation range, and the ride quality of the vehicle will deteriorate. This problem arises. Furthermore, if the lock-up clutch is released in a relatively wide range on the low engine speed side in order to cope with this problem, the fuel efficiency reducing effect of the lock-up clutch will not be effectively utilized.

Therefore, as shown in Japanese Patent Laid-Open No. 61-52427, for example, the lock-up clutch is controlled to be partially engaged and slipped in a predetermined operating range, compared to the case where the lock-up is completely released. This prevents engine vibration from being transmitted to the transmission while reducing deterioration in fuel efficiency. In a torque converter that performs such slip control, the first control region is
As shown in Figure 2A, there is a slip control region (A) where the above-mentioned slip control is performed, a converter region (B) where the lock-up clutch is completely released and converter is activated, and a lock-up region (L) where the lock-up clutch is engaged.
/U).

Incidentally, the running load of the vehicle also changes, for example, when the slope changes or when the vehicle weight changes.

When this running load changes, this means that the accelerator pedal is depressed, which causes the engine load to change. Therefore, the following problems with slip control have been pointed out. While driving in the slip control area, for example, if you enter a slope and the driving load increases, if you gradually depress the accelerator, the system will shift from the slip area to the converter area (transition from A to B in Figure 12A). do). Note that when moving to this converter region, the throttle opening rate is approximately 1.5/8. Now, when shifting to the converter region, the coupling force of the lock-up clutch is weakened, so the engine speed suddenly increases as shown in FIG. 12B. Since this sudden increase occurs even in response to the slightest accelerator operation by the driver, it feels very strange.

On the other hand, as an example of a torque converter that performs the same slip control, there is, for example, Japanese Patent Laid-Open No. 57-33253. In this patent application, the amount of slip in the slip control region is finely changed, and the amount of slip is set to be large in the converter region.

(Problems to be Solved by the Invention) When trying to prevent a sudden increase in engine speed when transitioning to the above-mentioned converter region, the following may occur. That is, as shown in FIG. 13, feedback control is performed in the slip control region, and when the shift to the converter region occurs, the duty of the duty solenoid that controls the amount of slippage of the lock-up clutch is gradually reduced. be. However, even if such control is performed to gradually reduce the duty value, the change in running load is only indirectly understood as a change in engine load. In other words, the duty value is gradually reduced only after the engine load shifts to the converter region.
Therefore, it cannot be said that the shift shock at the time of transition of the converter region has been improved.

In addition to the problem of shift shock during transition from the slip control area to the converter control area, another major problem with the prior art is the lack of acceleration feeling while driving in the slip control area. This is due to the following reason. For example, even if the running load increases and the accelerator is depressed, the
No. 253 proposes that the amount of slip increases only when the engine load changes within the slip region to a region close to the converter region, and as a result, the engine speed increases and the torque increases. In other words, even if the running load increases, the amount of slip does not increase unless the vehicle speed decreases, and this decrease in vehicle speed leads to a lack of sense of acceleration.

Therefore, the present invention was proposed in order to eliminate the drawbacks of the above-mentioned conventional examples.The purpose of the present invention is to provide a fluid that can provide a predetermined acceleration feeling even with changes in running load such as changes in road surface slope and changes in loaded weight. This paper proposes a slip control device for joints.

(Means and operations for achieving the object) As shown in FIG. 1, the present invention has a lock-up clutch mechanism in which the fastening force is controlled to a predetermined value. A slip control device for a fluid coupling comprising: a means for detecting a running load; and a means for receiving an output of the detecting means and correcting a lock-up clutch engagement force in accordance with the detected running load. It is characterized by

(Example) An example in which the present invention is applied to a torque converter for an automobile will be described below with reference to the accompanying drawings.

<Configuration of torque converter> First, the structure of the torque converter and its control hydraulic circuit will be explained with reference to Fig. 2.
For example, a pump 4 is fixedly attached to one side of the case 3 connected to the engine output shaft 2 and rotates integrally with the engine output shaft 2, and the other side of the case 3 is connected to the pump 4, and the other side of the case 3 is connected to the engine output shaft 2. A turbine 5 is rotatably provided in the pump 4 and is rotatably driven via hydraulic oil by the rotation of the pump 4, and a turbine 5 is interposed between the pump 4 and the turbine 5 to adjust the speed ratio of the turbine rotation speed to the pump rotation speed. It has a stator 6 that increases torque when the torque is below a predetermined value, and a lock-up clutch 7 interposed between the turbine 5 and the case 3.

The rotation of the turbine 5 is outputted by a turbine shaft 8 and inputted to a speed change gear mechanism (not shown), and the lock-up clutch 7 is connected to the turbine shaft 8 and is connected to the case 3. When fastened, the engine output shaft 2 is connected to the engine output shaft 2 through the case 3.
and turbine shirt l-8 are directly connected.

Further, hydraulic oil is introduced into the torque converter 1 through a main line 9 led from an oil pump (not shown) through a lock-up valve 10 and a converter inline 11, and the pressure of this hydraulic oil is The lock-up clutch 7 is always urged in the engagement direction, and a lock-up release line 13 led from the lock-up valve 10 is connected to the space 12 between the clutch 7 and the case 3. When hydraulic pressure (release pressure) is introduced into the space 12 from the line 13, the lock-up clutch 7 is released. Further, a converter outline 16 is connected to the torque converter 1 to send hydraulic oil to an oil cooler 15 via a pressure holding valve 14 .

On the other hand, the lock-up valve 10 has a spool 10a.
and a spring 10b that urges this to the right in the drawing, and both sides of the boat 10c to which the lock-up release line 13 is connected. 1-1. Od and a drain boat 10a are provided. Further, a control line 17 for applying pilot pressure to the spool 10a is connected to the right end of the valve 10 in the drawing, and
A duty solenoid valve 19 is installed in a drain line 18 branched from this control line 17.

This duty solenoid valve 19 repeatedly turns ON and OFF at a duty rate according to the input signal, and opens and closes the drain line [8] in extremely short cycles, so that the pilot pressure in the control line 17 corresponds to the above duty rate. Adjust to the desired value. Then, spring 1. is attached to this pilot 10a. At the same time, the release pressure in the lock-up release line 13 is applied to the spool 10a in the same direction as the urging force of the spring 10b, and these hydraulic pressures or The spool 10a moves due to the force relationship, and the lock-up release line 13 is communicated with the main line 9 (pressure regulation bow +-1od) or drain boat Oe, so that the lock-up release pressure becomes the pilot pressure. That is, it is controlled to a value corresponding to the duty rate of the duty solenoid valve 19.

Here, when the duty rate is at its maximum value, the flow rate from the control line 17 is at its maximum, and the pilot pressure or release pressure is at its minimum, so that the lock-up clutch 7 is completely engaged. Further, when the duty rate is at a minimum value, the drain amount is at a minimum, and the pilot pressure or release pressure is at a maximum, so that the lock-up clutch 7 is completely released. At a duty rate between the maximum value and the minimum value, the lock-up clutch 7 is in a slip state, and by adjusting the release pressure in accordance with the duty rate in this state, the slip amount of the lock-up clutch 7 is controlled. It is now possible to do so.

<Configuration of Control Circuit> Next, the electric circuit that controls the slip amount of the lock-up clutch 7 will be explained. As shown in FIG. A vehicle speed sensor 21 that detects ■ and a throttle sensor 2 that detects the engine throttle opening θ
2, a gear position sensor 23 that detects the gear position G of the automatic transmission, an engine rotation sensor 24 that detects the engine rotation speed N0, and a turbine rotation sensor 25 that detects the rotation speed NT of the turbine shaft 8. It consists of a vehicle weight sensor 26 that detects the vehicle weight and a slope sensor 27 that detects the slope of the vehicle body. The vehicle weight sensor is designed to indirectly detect the vehicle weight by detecting, for example, the degree of depression of the suspension.

In addition, the slope sensor 27 indirectly knows the slope of the slope by detecting the slope of the vehicle body, but instead, it can indirectly know the slope from changes in the throttle opening and changes in vehicle speed. You can also do this.

Then, the CPU 20 controls the duty solenoid hub 19 based on the signals from the sensors 21 to 27.
The duty ratio of the torque converter 1 is calculated, and the slip control of the torque converter 1, that is, the slip amount of the lock-up clutch 7 is controlled according to the flow chart shown in FIG.

<Outline of Operation of Example Control> The operation results of the slip control of this example will be explained using FIG. 4. The control of this embodiment is characterized by the following three points. That is, (1) When the running load increases in the slip control region, the response to the acceleration of the driver is made to be faster than in the past.

■Secondly, when attempting to shift from the slip control area to the converter area when the running load is increasing,
By reducing the difference in the amount of slip just before and after the transition, the shock during the transition is alleviated.

(2) Immediately after transitioning to the converter region, the amount of slip is controlled to gradually decrease to further reduce the shock at the time of transition.

FIG. 4 shows changes over time in the duty D for controlling the slip amount, the engine speed NE, the vehicle body acceleration, etc. when the slope a gradually increases over time during slip control operation. According to the control of this embodiment, when the vehicle body slope α increases, the duty D is decreased, that is, the slip amount is increased in response to the change in the slope. Then, since the engine load torque decreases, the engine rotational speed N increases, and as a result, the engine shaft output increases, resulting in an increase in vehicle body acceleration.

Incidentally, FIG. 4 also shows a case where the driver depresses the accelerator when the vehicle body slope α increases and the torque converter shifts from the control region or slip region to the converter region. That is, in the same figure, even if the vehicle body slope α increases until time t1 and maintains the upward slope angle after that, as long as the upward slope continues, the duty D is decreased and the slip amount is increased. are increasing. Because of this, the difference between the amount of slip immediately before and immediately after shifting to the converter region is smaller than in the conventional case, so there is less shock at the time of transition.

In order to realize the slip amount control operation as shown in FIG. 4, the present invention proposes two control modes. One is feedback control of the amount of slip as shown in FIGS. 5 and 6, and the other is feedforward control as shown in FIGS. 10 and 11.

<Feedback Control> Feedback control of the amount of slip will be explained according to FIGS. 5A to 6B. This feedback control converts the deviation (slip ff1) between the engine rotational speed N and the turbine rotational speed N'r (N5C=INEN Tl) into the target slip [INEN. It is like converging to . A feature of the feedback control of this embodiment is that when the running load changes, the target slip ff1N.

The idea is to change the

FIG. 5A is the main routine of slip control, and the fifth
Figure B shows a subroutine used as the main routine. The procedure shown in this flowchart is to calculate the duty rate, and the duty rate is actually pulse width modulated and output to the duty solenoid 19 by the not-shown part of the CPtJ20. Since this pulse width modulation is well known, its explanation will be omitted.

Now, in step S2 of FIG. 5A, the vehicle speed V thrower 1~
lever opening θ, engine speed NE, turbine speed NT,
The speed change position ffG is read from each sensor. Step S4
Then, the slip amount Ns is calculated.

NS" NONl In step S6, the vehicle weight W and the vehicle body slope α are read from the respective sensors. In step s8, the vehicle body slope a and the vehicle weight W that have been read are used to determine the slope corresponding to the slope according to FIGS. 6A and 6B. The correction coefficient ca and the correction coefficient Cw corresponding to the vehicle weight are read from the map.The characteristics of this map will be described later.

In step SIO, the target slip amount N. Calculate.

That is, N o ” N o *Cw * Ca The feature of this calculation formula is that if C,, C, is 1° or more, the target slip iN increases. Now, Fig. 6A. , and FIG. 6B, the correction coefficients Ca and Cw will be explained.The characteristic of Ca in FIG. 6A is that when the vehicle is on a downhill slope, the running load decreases, so the target slip N. is not changed.

On the other hand, when the road surface slope rises, the steeper the slope, the higher the target slip iN. It's like getting bigger. Also,
The characteristics of the vehicle weight correction coefficient CW in FIG. 6B are for a certain vehicle weight W. up to the target slip amount N. is not changed, and increases as the vehicle weight increases compared to Wo.] 5 The larger the amount, the larger the coefficient value C8 becomes than '°1°'. That is, the coefficients in Figs. 6A and 6B The characteristic is that the target slip amount N increases as the slope of the road surface becomes steeper or as the vehicle weight increases.

Returning to FIG. 5A, the explanation of the flowchart will be continued. In step S1.2, the deviation ΔN of the target slip amount N0 calculated in steps S] and O with respect to the current actual slip amount Ns is calculated.

ΔN=N, -N0 In step S14, it is determined from the vehicle speed V and throttle opening O obtained in step S2 whether the vehicle is in the current driving region or slip control region according to the characteristics shown in FIG. In FIG. 7, the slip control region is indicated by 1, the lock-up region is indicated by 1, and the converter region is indicated by IIT. In addition, in FIG. 7, a slip control area (2), a lock-up area II, and a converter area III are shown at each shift position.

If the current operating range is in either the converter range or the lock-arrow range, the process advances to step S26;
If it is in the slip control region, the process advances to step S16.

The case where the current state is not in the slip control area will be explained. In step S26, it is determined whether the current state is the current state or immediately after the transition from slip control to the converter region. If it is immediately after, the stepwise gradual decrease control of the slip amount as shown in FIG. 4 is not necessary, so the process proceeds to step S30, and well-known lock-up control or converter control (subroutine LUCNVT, not shown) is performed. . Since this LUCNVT is well known, its explanation will be omitted.

If it is determined in step S14 that the current operating range is in the slip control range, the control proceeds to step S16. In steps S], 6, the control parameters A and B (constants or variables) are determined, and the feedback amount U is calculated.

U=AXΔN −1−B Find the duty 82D.

D=D+△d.

Next, in step S22, the slip amount deviation is saved for the next calculation.

ΔN'=ΔN The PAUSE in step S24 is intended to execute feedback control at predetermined time intervals and also to allow the CPU 20 to execute other control routines.

Thus, when in the slip control region, step 8
2 to Step S1.4) In Step 326 to Step S22, feedback control is performed to change the amount of slip in accordance with the running load.

Next, control at the time of transition from the slip control region to the converter region will be explained. That is, this is a case where the control region determined from the vehicle speed and throttle opening as shown in FIG. 7 is about to shift to the converter region even though the slip control as described above is performed.

At this time, the control is performed in step S14#step 526-
The process proceeds to step S28. This subroutine LUCNVTAIL of step 828 is shown in FIG. 5B.

In FIG. 5B, if it is determined in step S60 that the area after the transition is a converter area, steps 368 to
In the loop of step S72, the duty rate is controlled to gradually decrease until D m l n where lock-up is completely released. The situation at this time is shown in FIG. 9(a).

Further, if it is determined in step S60 that the area after the transition is the lockup area, the duty rate is controlled to gradually increase up to Dmax until the lockup becomes fully engaged in a loop from step 862 to step S66.

The situation at this time is shown in FIG. 9(b).

The reason why such gradual decrease control or gradual increase control is performed is to avoid reducing the shock.

〈Feet for 1/Control〉 In the control shown in FIG. 5, the slip amount control is set to the target slip amount N.

This was done by feedback control such as convergence of the actual slip amount Ns with respect to the actual slip amount Ns. The flowchart in FIG. 10 performs this slip amount control in a feedforward manner.

First, in step S100, vehicle speed ■, throttle opening θ, engine speed NE, turbine speed N□, and shift position G are read from each sensor. In step 5102, it is determined whether the current driving region is in the slip control region, based on the determined vehicle speed ■ and throttle opening θ, according to the characteristics shown in FIG. If it is not in the slip control area, the fifth
The same procedure as step 326 to step S30 in Figure A is performed. In step 5104, the vehicle weight W, the vehicle body slope α
are read from each sensor. In steps 31 and 06, 1.1. A
Figure 1] Correction coefficient C8 corresponding to the slope according to Figure B
゛, The correction coefficient Cw' corresponding to the vehicle weight is not read from the map. The characteristics of this map are opposite to those shown in FIG. This is because, in the case of feedback control, the duty D is reduced by increasing the target slip amount No as the running resistance increases, whereas in the case of feedforward, the duty D is directly reduced.

Therefore, there is no difference between FIG. 6 and FIG. 11 from the viewpoint that the amount of slip increases as the running resistance increases.

In step 5108, duty D is read based on vehicle speed V and throttle opening θ. And step S
], 1. 0 to calculate the final duty D.

D=D*Cw'*C.

Even with such feedforward, the control operation shown in FIG. 4 can be obtained.

<Effects of Examples> In this way, the following effects can be obtained from the above embodiments. That is, (1): When the running load increases in the slip control region, the amount of slip is increased as a response to acceleration by the driver, so the sense of acceleration is greater than in the past.

■Secondly, when attempting to shift from the slip control area to the converter area when the running load is increasing,
By gradually increasing the amount of slip, it was possible to reduce the difference in slip m between immediately before and after the transition, thereby alleviating the shock during the transition.

- Immediately after transitioning to the converter region, the amount of slip is controlled to gradually decrease, thereby further reducing the shock at the time of transition.

The present invention can be modified in various ways without departing from the gist thereof. For example, although the above embodiments have been described with reference to embodiments applied to torque converters for automobiles, it is obvious that the present invention can also be applied to general fluid couplings.

(Effects of the Invention) As explained below, according to the slip control device for a fluid coupling of the present invention, the engagement force of the lock-up clutch is variably controlled according to the running load. Even when going uphill, you can get the desired feeling of acceleration.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the present invention in detail, Fig. 2 is a sectional view of the torque converter and hydraulic circuit used in the embodiment, Fig. 3 is a block diagram of the control circuit of the embodiment, and Fig. 4 is the embodiment. Figures 5A and 5B are flowcharts of the control procedure when the control of the embodiment is realized by feedback control; Figures 6A and 6B are diagrams of the correction coefficients used in feedback control; Figure 7 is a diagram explaining the operating range of the example, Figure 8 is a diagram showing the conversion characteristics from the feedback amount to the duty correction amount used in the example, and Figure 9 is a diagram showing the characteristics of the example. Fig. 10 is a flowchart of the control procedure when the control of the embodiment is realized by feedforward control; Figures 12A, 12B, and 13, which show the characteristics of the correction coefficient in the case of accuracy, are diagrams explaining the drawbacks of the prior art. In the diagram, 1...torque converter, 2 engine output shaft, 8...
...Turbine shaft, 10...Duty solenoid hub for lock-up, 20...CPU, 24.2
5...Engine rotation sensor, turbine rotation sensor. Figure 10 (lower lire) Graduation θ on page 1 (up) Figure 11A 1st old diagram

Claims (1)

[Claims] (1) In a slip control device for a fluid coupling having a lock-up clutch mechanism in which the fastening force is controlled to a predetermined value, there is a means for detecting running load, and a lock-up clutch that receives the output of the detecting means. A slip control device for a fluid coupling, comprising means for correcting a fastening force of the fluid coupling in accordance with a detected running load.