JPH01206159A - Device for controlling slip of torque converter - Google Patents

Abstract

PURPOSE:To properly control slip in line with the change in operating conditions by setting the target value of a slipping quantity between the input side and output side members of a lock-up clutch based on a map which is formed in accordance with the operating condition of an engine. CONSTITUTION:A CPU 20 has two maps for giving the slipping quantity between the engine output shaft 2 and turbine shaft 8 of a torque converter 1 from the relation between a throttle opening theta (sensor 22) and a vehicle speed V (sensor 21), one for coping with the time when an engine output demand is strong or when an output condition is low and one for coping with an ordinary output condition. By selecting a map in accordance with the operating condition of the engine, the target value of slipping quantity is set in accordance with the operating condition of the engine to control the slipping quantity of a lock-up clutch 7 via a duty solenoid valve 19 and a lock-up valve 10. Thereby, a proper slip control can be carried out improving fuel consumption and a traveling property.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a slip control device in a lock-up clutch of a torque converter of an automatic transmission equipped with a lock-up clutch.

(Prior Art) It is known that an automatic transmission is provided with a torque converter that transmits torque through fluid before the transmission section, and a lock-up clutch that transmits torque without using the torque converter.

When the lock amplifier clutch is engaged, the engine output can be transmitted as is, which has the advantage of improving fuel efficiency, but on the other hand, it has the disadvantages of not being able to amplify torque, making it difficult to reduce vibrations, and making the ride uncomfortable. be.

Considering these characteristics of lock-up operation, in order to minimize the disadvantages of lock-up while avoiding a significant deterioration in fuel efficiency, it is necessary to maintain a certain amount of slip between the input-side member and output-side member of the lock-up clutch. It is known to drive while allowing.

For example, Japanese Patent Application Laid-open No. 57-33253 discloses a slip control device for a lock-a-pull clutch in a torque converter that performs feedback control to maintain a constant slip amount, or rotational speed difference, between an input side member and an output side member. Disclosed.

In such a slip control device, the amount of slip is usually set in relation to the operating state of the engine, that is, the engine load and engine speed, or the vehicle speed.

(Problem to be Solved by the Invention) However, if the operating conditions of the engine differ, the appropriate amount of slip will also differ, and it is desirable to change the setting of the amount of slip accordingly. For example, when the engine output is decreasing or when the engine is accelerating, there is a strong demand for torque in order to improve driving performance and acceleration, so slippage is relatively greater than during normal operation. It is desirable to increase the amount.

However, conventional slip control devices did not take these conditions into account and controlled the slip amount to a constant amount, making it impossible to achieve appropriate slip control in response to changes in engine operating conditions. .

The present invention was constructed in view of the above circumstances, and by performing appropriate slip control in response to changes in engine operating conditions, it maintains the fuel efficiency improvement function while also achieving excellent running performance and acceleration performance. The present invention aims to provide a slip control device for a torque converter.

(Means for Solving the Problems) The above-mentioned object of the present invention is to provide a lock-up clutch, and adjust the amount of slip of the lock-up clutch so that the amount of slip of the output-side member with respect to the input-side member of the lock-up clutch becomes a predetermined target value. In the slip control device for a torque converter, which controls the amount of torque transmitted from the engine, the target value is set in at least two different patterns depending on the operating state of the engine; This can be achieved by a torque converter slip control device characterized by comprising a selection means for arbitrarily selecting the above-mentioned pattern and providing a target value for the control when controlling the amount of slip.

The selection means automatically selects a pattern in which the target value is set relatively small when the condition and/or state is detected according to the output of the detection means for detecting a condition where the engine output decreases and/or an acceleration state. do.

(Operation) According to the present invention, the target value of the slip amount between the input side member and the output side member of the lock amplifier clutch is set based on a map created according to the operating state of the engine.

Then, the slip amount of the lock-up clutch is controlled so as to reach this target value. Feedback control can also be applied to this control.

In the present invention, at least two maps of this target value are prepared, and the engine operating conditions, for example, when the engine is in an accelerating state or when the driver selects driving that emphasizes power performance, are compared to the normal one. A map is used that sets a target value with a relatively large amount of slip.

Furthermore, it is preferable to set a relatively large target value for the amount of slip even when the engine is operating in a cold state, when traveling at high altitudes, or when an external load is applied to the engine such as when the air conditioner is operating.

(Description of Embodiment) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

The structure of the torque converter and its control hydraulic circuit will be explained with reference to FIG. A rotating pump 4, a turbine 5 rotatably provided on the other side of the case 3 to face the pump 4, and rotationally driven via hydraulic oil by the rotation of the pump 4; A stator 6 that is interposed between the turbine 5 and the stator 6 that increases torque when the speed ratio of the turbine rotation speed to the pump rotation speed is below a predetermined value; and a lock that is interposed between the turbine 5 and the case 3. It has an up clutch 7. 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.
When the engine output shaft 2 and the turbine shaft 8 are connected to the case 3, the engine output shaft 2 and the turbine shaft 8 are directly connected through the case 3.

Further, hydraulic oil is introduced into the torque converter 1 through a main line 9 led from an oil pump (not shown) through a lockup pulp 10 and a converter line 11, and the pressure of this hydraulic oil is The lock-up clutch 7 is always biased 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 amplifier 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 pulp 10 is spooled in a spool 10a.
and a spring 10b that urges this to the right in the drawing, and a pressure regulating port IQd and drain bow) 10e to which the main line 9 is connected on both sides of the port 10c to which the lock-up release line 13 is connected. It is equipped with

Further, a control line 17 for applying pilot pressure to the spool 10a is provided at the right end of the valve 10 in the drawing.
A duty solenoid valve 19 is installed in a drain line 18 branched from the control line 17.

The duty solenoid valve 19 repeatedly turns on and off at a duty rate according to an input signal to open and close the drain line 18 in extremely short cycles, thereby increasing the pilot pressure in the control line 17 to a value corresponding to the duty rate. Adjust to.

This pilot pressure is applied to the spool 10a in a direction opposing the biasing force of the spring 10b, and the release pressure in the lock-up release line 13 acts in the same direction as the biasing force of the spring 10b. The spool 10a moves due to the relationship between these oil pressures and biasing forces, and the lock-up release line 13 is moved.
is communicated with the main line 9 (pressure regulation port 10d) or drain port 10e. By this operation, the lock-up release pressure is controlled to the above-mentioned pilot pressure, that is, a value corresponding to the duty rate of the duty solenoid valve 19.

Here, when the duty rate (ON time ratio during the ION-OFF cycle) is at a maximum value close to 10%, the amount of drain from the control line 17 is at its maximum, and along with this, the pilot pressure or release pressure is at its minimum. When this happens, the lock-up clutch 7 is completely engaged, and when the duty rate is at a minimum value close to 0%, the drain amount is at its minimum, and the lock-up clutch 7 is accordingly completely released. It has become. At a duty rate intermediate between the maximum value and the minimum value, the lock-up clutch 7 is in a slip state, and within this state, the lock-up clutch 7 is adjusted by adjusting the pilot pressure or release pressure according to the duty rate. The amount of slip can be controlled.

In order to control the amount of slippage of the lock-up clutch 7, the device of this embodiment includes a control device, that is, a CPU 20.

The CPU 20 includes a vehicle speed sensor 21 that detects the vehicle speed of the vehicle, a throttle sensor 22 that increases the throttle opening of the engine, a gear position sensor 23 that detects the gear position of the automatic transmission, and a gear position sensor 23 that detects the engine rotation speed. Signals from an engine rotation sensor 24 that detects the rotation speed of the turbine shaft 8 and a turbine rotation sensor 25 that detects the rotation speed of the turbine shaft 8 are input.

Furthermore, the CPU 20 receives a signal P representing the atmospheric pressure, a signal T representing the engine cooling water temperature, a signal representing the operating state of the air conditioner, and the manual selection state of the transmission, that is, whether the transmission lever is in the power range or not. Signals, etc. are input without checking whether it is in the drive range.

Then, the CPU 20 adjusts the duty of the duty solenoid pulp 19 according to the operating state based on the signals from the sensors 21 to 25, the atmospheric pressure signal P, the water temperature signal T, the air conditioner operating state signal, and the manual selection state signal. The torque converter 1 (lock-up clutch 7) is controlled by calculating the ratio.

The lock-up clutch 7 is controlled according to a predetermined control program, and a flowchart of this program is shown in FIG. 2, fat.

In FIG. 2 (al), in step S1, the CPU 20 first reads the vehicle speed ■, throttle opening θ, engine speed Ne, turbine speed Nt, and gear G based on the signals from the sensors 21 to 25. Next, The CPU 20 executes the subroutine of the control content shown in FIG. 2 fb) to set the target slip amount No. in the slip control (
S2).

The CPU 20 is equipped with a map that gives the amount of slip between the engine output shaft 2 of the torque converter 1 and the turbine shaft 8 from the relationship between the throttle opening degree O and the vehicle speed ■, and sets the target slip iNo based on this map. It looks like this.

In this example, there are two maps, one corresponding to when the engine output is strongly requested or the engine output status decreases, and one corresponding to the engine's normal output status. The output state and the level of the driver's output request are judged and one of the maps is selected as appropriate.

In FIG. 2(b), the CPU 20 outputs an atmospheric pressure signal P,
Reads the water temperature signal T, air conditioner operating status signal, and manual select status signal (SSl), and determines whether the atmospheric pressure P is smaller than a predetermined value to determine whether the vehicle is traveling at a high altitude (SS2) . If the determination is NO, the CPO 20 determines whether the engine coolant temperature T has not reached a predetermined value (SS
3). Furthermore, the CPU 20 sequentially determines whether the air conditioner is on and whether the manual selection state is in the power range selected state (SS4.5S
5).

Then, if the atmospheric pressure P is lower than a predetermined value, the water temperature T is lower than a predetermined value, the air conditioner is turned on, or the power range is selected, the CPU 20 Select the map shown in Fig. 4 (5S6), then select the target slip ilN corresponding to the vehicle speed ■ and the throttle opening θ.

(SS7).

In addition, if none of the above cases apply, CPU2
0 selects the map in Figure 3 and reads the amount of slip (SS
8) Correspondingly, a target slip amount No. in slip control is set (SS7).

Note that in FIGS. 3 and 4, the slip amount a is larger than the slip amount s.

As is clear from comparing FIG. 3 and FIG. 4, the value of the amount of slip corresponding to the same throttle opening θ and vehicle speed V is larger in FIG. 3 than in FIG. 4. Therefore, when the map shown in Fig. 3 is selected, the target slip amount N
o, the target slip lNo becomes relatively larger than when the map shown in FIG. 4 is selected.

After setting the target slip amount No. using the above procedure, the CPU
20 calculates the actual slip amount Ns (=lNe-NtI) of the torque converter 1 in steps S3 and S4, and also calculates the deviation ΔN (=Ns-No) of this actual slip 11Ns with respect to the target slip amount No.

Then, in step S5, the CPU 20 determines whether the driving state indicated by the vehicle speed ■ and the throttle opening θ belongs to a preset slip region of the torque converter 1, that is, a region in which slip control is performed.

When the operating condition does not belong to the slip region, C
After replacing the deviation ΔN with the previous value ΔN'' according to steps 86 to s7, the PU 20 determines whether the operating state belongs to the lock amplifier region, that is, the operating region in which the candlestick clutch 7 is fully engaged. judge. As a result, when the operating state belongs to the lock-up region, the duty solenoid valve 19 is
The duty rate of is set to the maximum value Dmax.

If it does not belong to the lock-up region, it is determined to be the converter region, that is, the operating region in which the lock-up clutch 7 is released, and the duty rate is set to the minimum value Dmin in step S9.

Then, in both the lockup area and the convert area, step S10 is performed.
At this point, a control signal is output to the duty solenoid valve 19 so as to obtain the respective duty rates.

As a result, in the lock-up region, the pilot pressure applied to the spool 10a of the lock-up valve 10 shown in FIG. Ru. In the converter region, the pilot pressure or release pressure is maximized and the lock-up clutch 7 is completely released.

Furthermore, when the operating state belongs to the slip region, the CP
U20 executes steps Sll to S13, and calculates the feed bank amount U according to the following equation (i) in step Sll.

U is A×ΔN+BXΔN”...(i) Here,
Δ■゛ is the deviation of the actual slip amount Ns obtained in step S7 during the previous control with respect to the target slip amount No.

Further, in step S12, this feedback l
By setting the correction amount ΔD of the duty rate corresponding to u based on the map in FIG. 7, and correcting the previous duty rate D′ with this correction amount ΔD, the current duty rate D ) is calculated. After replacing the deviation ΔN obtained in the current control with the previous value ΔN' (S13), a control signal is output to the duty solenoid valve 19 so as to obtain the duty rate corrected as described above in step S12.

As a result, when the current and previous deviations ΔN and ΔN゛ are negative, that is, when the actual slip amount Ns is smaller than the target slip amount No, the feedback amount U and the correction amount ΔD of the duty rate also become negative, and the duty rate is reduced. As the rate decreases, the amount of drain from the duty solenoid valve 19 decreases and the pilot pressure or lock-up release pressure increases, and as a result, the lock-up clutch 7
is controlled in the releasing direction, and the actual slip amount Ns increases.

Also, on the contrary, the current and previous deviations ΔN, ΔN
When ゛ is positive, that is, the actual slip amount Ns reaches the target 1lN
When it is larger than o, the duty ratio is increased and the lock amplifier release pressure is decreased, so that the lock-up clutch 7 is controlled in the engagement direction and the actual slip 11Ns is reduced, and in this way the actual slip is reduced. The amount Ns converges to the target slip 1jlNo. In addition, the current deviation ΔN
When the positive and negative signs of the previous deviation ΔN'' are opposite, that is, when the actual slip amount Ns has almost converged to the target slip amount No, the feedback lu or duty rate correction amount ΔD becomes zero or an extremely small value. Therefore, the actual slip amount Ns is maintained at a value that is equal to or very close to the target slip amount No.

Note that even in slip control when the engine that requires output is in an accelerating state, the map shown in FIG. 4 is selected and a relatively small target slip amount No. is set.

(Effects of the Invention) According to the present invention, it is possible to perform an appropriate slip control device that can meet each output request according to engine operating conditions, and to obtain good results in terms of both fuel efficiency and running performance. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a torque converter to which the present invention can be applied, FIG. 2(a) is a flowchart of a slip control program according to an embodiment of the present invention, and FIG.
b) is a flowchart of a subroutine for determining the target slip amount used in FIG. ... Torque converter, 2 ... Engine output shaft, 3 ... Case, 4 ... Pump, 5 ... Turbine, 6 ...・Stator, 7...Lock-up clutch, 8...
...Turbine shaft, 9...Main line,
10...Rock-up pulp, 11...
・Converter line, 12...Space part, 13・
...Lockup release line, 14...
Pressure holding valve, 15...Oil cooler, 16...
...Converter outline, 17...System J
B line, 18... Drain line, 19...
...Duty solenoid valve, 20...
CPU. Figure 2 (b)

Claims (2)

[Claims] (1) A lock-up clutch is provided, and the amount of slip of the lock-up clutch is controlled so that the amount of slip of the output side member relative to the input side member of the lock-up clutch becomes a predetermined target value, thereby controlling the amount of torque transmitted from the engine. In the slip control device of the torque converter to be controlled,
target setting means for setting the target value in at least two different patterns depending on the operating state of the engine;
A slip control device for a torque converter, comprising a selection means for arbitrarily selecting the pattern and providing a target value for the control when controlling the slip amount. (2) The selection means automatically sets a relatively small target value when the condition and/or state is detected in accordance with the output of the detection means for detecting the condition and/or acceleration state in which the engine output decreases. The slip control device according to claim 1, wherein a pattern is selected.