JPS60143268A - Controller for slip of torque converter - Google Patents

Abstract

PURPOSE:To prevent the occurrence of hunting and an answering lag, by a method wherein a control constant for slip control is varied according to the load condition of a power source and so as to always match such condition. CONSTITUTION:A load detecting means 6 for detecting the load condition of a power source 1 and a combining force control constant varying means 7 for varyilng a control constant for slip control according to a load condition signal from the means 6 are provided, and the control constant is varied according to the load condition of the power source 1 and so as to always match such condition. This enables the slip amount of a troque converter to be prevented from high hunting because of the control constant being too high under a high load condition or permits prevention of the occurrence of a fact that a long time elapses until the slip amount of the torque converter is regulated to a set value because of the control constant being too low under a low load condition.

Description

Detailed Description of the Invention (1) Technical Field The present invention relates to a torque converter used by being inserted into a power transmission system such as an automatic transmission for a vehicle, and in particular, to a torque converter that is used to adjust the relative rotation (slip) between its input and output elements to an appropriate setting value. The present invention relates to a slip control device for a torque converter that is capable of such slip control.

(2) Conventional torque converters transfer power between their input and output elements via hydraulic oil and have a torque increasing function and a torque fluctuation absorption function, but on the other hand, they avoid relative rotation (slip) between input and output elements. power transmission efficiency is poor. Therefore,
Although torque fluctuations are still a problem, under conditions where the torque increase function is almost unnecessary, the torque converter can be used to perform slip control so that the relative rotation between the input and output elements is the minimum necessary (set value) to absorb torque fluctuations. Slip control type torque converters that can increase power transmission and delay efficiency while ensuring the necessary torque fluctuation absorption function are already in practical use in some areas.

This torque converter generally includes an input element driven by a power source, an output element driven by hydraulic oil circulated by the input element, and a clutch that appropriately limits the amount of slip between these input and output elements. (generically referred to as a direct coupling clutch or lock-up clutch), and is configured to be capable of slip control so that the amount of slip between the nine input and output elements becomes a set value by adjusting the coupling force of the clutch. It's normal.

For this slip control, the above-mentioned clutch is usually a hydraulic type, and the slip control is usually performed by feedback or feedforward control of the hydraulic pressure that determines the coupling force of the shift latch using a solenoid valve controlled by a tutee. Deroru. On the other hand, in this case, it is known that the rate of change in torque converter slip amount with respect to torque converter slip (%) varies depending on the load condition of the power source, as shown in Figure 10. As the condition changes, the range of change in torque converter slip roughness increases even with the same change in duty (%).

However, in the conventional slip control device, the control constant was constant regardless of the load condition of the power source, so if this is used as a determiner in accordance with the medium load condition, then in this medium load condition, Fig. 11 As shown in Figure 2, the torque converter slip amount causes hunting and although the torque converter slip amount is stably and quickly brought to the set value without flashing for a long time, under high load conditions the control constant becomes too thick and the torque The converter slip amount also causes hunting as shown in FIG. 11, and in a low load state, the control constant is too small and it takes a long time for the torque converter sling lid to reach the set value as shown in FIG. 11. This is due to the fact that, as described above with reference to Figure 10, the rate of change in the amount of torque converter slip with respect to the tute is sudden in a heavy load condition, and becomes gradual in a low load condition. Hunting under load conditions causes a problem in which vibration occurs due to insufficient slip in the torque converter when the amount of torque converter slip falls significantly below the set value, and response delay under low load conditions causes torque A problem arises in that the amount of converter slip greatly exceeds the set value for a long period of time, impeding the same effect on fuel efficiency of the power source due to the use of a slip-controlled torque converter, and either case is undesirable.

(8) Purpose of the Invention The purpose of the present invention is to solve the above-mentioned problems by configuring a slip control device so that the control constant can be changed to always match the load condition of the power source. .

(4) Structure of the Invention For this purpose, the slip control device of the present invention, as shown in FIG. Output element 8;
A slip control type comprising a clutch 4 that appropriately limits the amount of slip between these input and output elements, and a clutch control means 5 that controls the coupling force of the clutch according to a control constant to bring the slip lid to a set value. The torque converter is characterized by being provided with a load detecting means 6 for detecting the load state of the power source 1, and a coupling force control constant changing means 7 for changing the control constant according to a load state signal from the means. shall be.

(5) Examples Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows the slip control device of the present invention together with a torque converter in an automatic transmission for a vehicle to be controlled by the slip control device, in which lO is an engine as a power source, 11 is its crankshaft, 12 is a flywheel, and 18 is a Torque converter, 14) is a torque converter output shaft. During operation of the engine 10, the crankshaft 11 rotates together with the flywheel 12, and the torque converter 18 is drivingly connected to the crankshaft 11 via the flywheel 12 and is connected to a pump impeller (input element) which is constantly driven by the engine. ) 18a, a turbine launch (output element) 1.9b opposed thereto, and a stator (reaction force element) 18c. is placed on a hollow fixed shaft 16 via a one-way clutch 15. The torque converter 18 is supplied with working fluid from the pump 17 to its internal converter chamber 18d via the supply path 18, and returns this working fluid to the internal converter chamber 18d.
9 and returned to the reservoir 20, and is cooled by a heat radiator 21 provided in the middle. In addition, a pressure holding valve (not shown) is inserted in the return path b 19, which reduces the pressure (converter pressure) below the value in the converter chamber 18d.
Keep it at c. Thus, as described above, the pump impeller 18a driven by the engine stirs the internal working fluid, causes it to collide with the turbine runner 18b, and then flows through the stator 18c, during which time the turbine runner 18b is torqued under the reaction force of the stator 13c. Rotate while increasing.

Torque converter 18 in operation in such a converter state
can transmit the power of the engine 10 to the output shaft 14 while suppressing vibration and increasing torque without causing slip (relative rotation) between the input/output elements 18a and 18b. The power from the output shaft 14 is shifted by the gear transmission mechanism 42 to rotate the drive wheels of the vehicle, thereby allowing the vehicle to travel.

The torque converter 18 is further provided with a clutch (lock-up clutch) 22 in order to use a slip control type and a lock-up type that can limit and stop the above-mentioned slip, and this is drivingly coupled to the output shaft 14 via a torsional damper 23. The lock-up chamber 24 is set to be movable in the axial direction on this axis. The clutch 22 moves to the left during the system due to the differential pressure between the lock-up pressure PL/u in the lock-up chamber 24 and the converter pressure Pc in the converter chamber 18 (l), and operates the input/output elements with a force corresponding to this differential pressure. 13a+18
By drivingly coupling between b? ) Lux converter 13
may limit and cancel slips.

The lock-up pressure PL//u is adjusted as described below by the slip control valve 25.For this purpose, the lock-up chamber 24 is connected to the slip control valve 25 via the hollow hole of the shaft 14 and the circuit 26. 25a. The valve 25 is separately provided with a bow 25b through which the converter pressure Pc is guided by the circuit 27, and a drain boat 25c.
25b and 25c, and when the spool 25d moves to the left in the figure, the spool 25a is connected to the boat 25b,
When d moves to the right in the figure, the boats 25a are connected to the boats 25C, respectively.

The spool 25d has a force exerted by the converter pressure Pc acting on the pressure receiving area difference of the spool land in the pressure receiving area 25e,
The control pressure Ps is controlled in response to the force exerted by the lock-up pressure PL/u acting on the pressure receiving area difference of the spool land in the chamber 25f and the force exerted by the control pressure Ps acting on the left end surface of the spool in the chamber 25g. The pressure generating circuit 28 and the solenoid valve 29 are constructed as follows.

That is, the reference pressure (for example, line pressure in the case of an automatic transmission) PL is supplied to the control pressure generation circuit 28 from its one end 28a,
This line pressure is passed through orifice 28C128d to circuit 2.
The other end 28b of 8 is closed. By determining this drain amount using the duty-controlled electromagnetic valve 29, a control pressure Ps can be generated between the orifices 280.degree. 28a, and this is guided to the drain chamber 25g by the circuit 80.

The solenoid valve 29 includes a plunger 29a and a solenoid 29b that moves the plunger 29a to the left in the figure when energized.
When the solenoid 29b is energized, the plunger 29a is pushed away by the drain working fluid from the drain opening end 28b to allow the above drain, and when the solenoid 29b is energized, the plunger 29a moves to the left to close the drain opening end 28b. shall be. Then, energizing (energizing) the solenoid valve solenoid 29b
is the eighth signal from the slip control computer 81 that performs slip control of the torque converter, which is the object of the present invention.
Duty control is performed so that the pulse signal is repeatedly performed during the pulse width (on time) of the pulse signal as shown in FIGS. (a) and (b). As shown in FIG. 8(a), when the tutee is small, the time for the solenoid valve 29 to close the drain opening end 28b is short, and therefore the control pressure Ps is at the fourth
As shown in the figure, it is a constant value determined by the difference in pressure receiving area between the orifices 28c and 28d. As the duty (%) increases as shown in FIG. 8(b), the solenoid valve 27 closes the drain opening end 28bi for a long time, so the control pressure Ps gradually increases as shown in FIG. 4, and finally is line pressure P
becomes equal to L.

In FIG. 2, as the control pressure Ps increases, this control pressure causes the spool 25d to move to the right as shown in FIG. 11 decreases. On the other hand, control pressure P
As s decreases, the spool 25d is moved to the left as shown in FIG. 5(b) to gradually open the port 25ak to the port 25b, and the lockup pressure PL/ increases. By the way, since the control pressure Ps increases as the tutee (%) increases as shown in Fig. 4, the lockup pressure PL/
As shown in FIG. 6, is kept equal to the converter pressure Pc in a region where the duty (ch) is small, decreases as the duty (ch) increases, and is finally changed to zero. When the lock-up pressure PL/u reaches the maximum value equal to the converter pressure Pc, the lock-up clutch 22 is released because the pressures in the chambers 18d and 24 are equal, and the torque converter 8 is connected to the converter with the highest slip amount. (/V) state, lock-up pressure PL/
/When Iu becomes zero, the lock-up clutch 22 is in the chamber 18.
When the lock-up pressure PL/u reaches an intermediate value, the lock-up clutch 22 is completely coupled to the converter pressure Pc in the chamber 18d, and the torque converter 8 is operated in the loss step (4) state with zero slip amount. Pressure Pc in 24, difference between PL/u, nail lock-up pressure P
A sliding connection is made with a connection force according to the value of L/, and the torque converter 8 functions in a slip control state.

The slip control computer 81 is operated by the power supply +V, and receives a signal 3g related to the gear position (gear ratio) of the gear transmission mechanism 42 from the gear position sensor 32 - rotation speed sensor 88
from the engine rotation speed (rotation speed of the human power element 18a) signal Sir, from the rotation speed sensor 84 from the gear transmission mechanism (4
2) Output rotation speed (this rotation speed is multiplied by the gear ratio of the gear transmission mechanism 42 to obtain the rotation speed of the output element 18b) signal Sor
, the engine throttle opening signal "TH" from the throttle opening sensor 85, and performs the tutee control of the electromagnetic valve 29 as described below.

For this purpose, the computer 81 is, for example, a microcomputer as shown in the block diagram of FIG. It consists of a memory (ROM) 87, an input/output interface circuit (1) aS, and an I'/D converter 89.

And this microcomputer has a sensor 88. ．． 34
The signals Sir and Sor from the sensor 85 are inputted after being multi-waveform shaped into the waveform shaping circuit 40, and the signal STH from the sensor 85 is converted into a digital signal by the converter 89) and is inputted from the sensor 82. The control program shown in FIG. 8 is executed based on these input signals, and the control program shown in FIG.
shall be controlled.

FIG. 8 shows an interrupt routine stored in ROM87.
U86 repeatedly executes this routine in step 49 in response to an interrupt signal input at regular intervals. First, in step 50, the initial values of the MPU 86 and 1038 are set (internalized), and then in step 51, the signal Sg from the sensor 82 is set.
The gear position (gear ratio 1) of the gear transmission mechanism 42 is read, and in the next step 52, the signal Sir from the sensor 88 and the engine rotation speed (the rotation speed of the input element 18a) NE are read, and in step 58, the signal Sir from the sensor 88 is read. In step 54, the signal Sor includes the output shaft rotation speed No1i of the gear transmission mechanism 42, and the rotation speed iN of the turbine runner (output element) 18b is determined in step 54.
.

x1, and in the next step 55, the engine throttle opening TH is read from the signal STH from the sensor 85.

After that, the control proceeds to step 56, where it is determined from the throttle opening TH1 output shaft rotational speed No. (vehicle speed) whether or not the torque converter 18 is in a slip region where slip control is required (in this example, the torque converter 18 is locked up). ). If the torque converter 18 is not in the slip region, the torque converter 18 should be placed in the converter state, so step 57 is selected, the duty is set to 0%, and the torque converter 18 is placed in the demand-transfer state.

If it is in the slip region, step 56 selects step 58, where the torque converter slip amount ΔN is set to ΔN
= NE-N, calculate accordingly. In the next step 59, the deviation ΔX of the actual slip amount ΔN with respect to the slip amount set value ΔNr is calculated by ΔX=ΔN−ΔNr, and in the next step 60, the proportional constant of the integral control according to the load condition of the engine IO is set to 1 and proportional to Select the control proportional constant Kp (in this example, PI sub-control is used, so the control constant is determined by these). When making this selection, the load condition of the engine IO is represented by its throttle opening TH and turbine rotation speed N, so the table data in the following table based on these is R
The OM87 is stored in advance, and the throttle opening TH and turbine rotational speed N, 'f are calculated from these table data.
Based on c, proportional constants Ki and Kp are calculated as hk using a table lookup method.

Table data of T Kp In these table data, Ki and Kp are respectively equal to the throttle opening TH under the same turbine rotation speed.
The load increases as the throttle opening increases, and if the throttle opening is the same, the load increases as the turbine rotational speed NT decreases. Therefore, as the throttle opening TH increases, the load increases, and as the turbine rotational speed NT decreases, the load increases. , Ki, and Kp are made smaller as the load becomes larger and larger as the load becomes smaller for each load state, so as to match the characteristics shown in FIG. 10.

In the next step 61, the proportionality constant K selected as described above is
Perform the division of i, Kp and duty.

That is, first, the tute value D (NEW) by integral control
In order to calculate the difference, 1·ΔX is added to the product of the constant Ki and the slip amount deviation ΔX to the previous tute value D (OLD). Next, based on the duty value D(NEW) obtained by the integral control obtained in this way, the current duty value, which takes into account the proportional control, can be requested as D=D(NEW) 10 Kp·ΔX. In the next step 62, the previous duty value D (
OLD) is updated to the current tutee value, and in step 68, this tutee value is outputted to the electromagnetic valve solenoid 29b via the amplifier 41 shown in FIG.

The above control ends with step 57 or step 68 and step 64, or the slip control of the torque converter 18 in steps 58 to 63 changes the output duty by an amount proportional to the constants Ki and Kp according to the slip deviation ΔX. In order to increase the lock-up pressure PL/, the lock-up pressure PL/ is lowered each time the control is repeated, as is clear from FIG. Therefore, as is clear from the foregoing, the torque converter 18 has its slip amount ΔN successively reduced, and when transitioning from the comperme state to the slip control state, the slip amount ΔN has been brought to the set value ΔNr as shown in FIG. and is maintained at this set slip amount.

By the way, the proportional constants Ki and Kp are changed in step 60 according to the load condition of the engine IO so that the control constants are just right, so no matter what the engine load condition, the slip control is performed as shown in FIG. Even when large hunting occurs, the processing is executed without causing a large response delay.

(6) Effects of the Invention Thus, in the present invention, for example, as described above, the slip control device is configured to change the control constant according to the load condition of the power source (engine number) so as to always match the load condition, so that it is possible to This is to prevent the torque converter slip cover from hunting greatly due to the control constant being too thick under low load conditions, and from requiring a long time for the torque converter slip amount to reach the set value due to the control constant being too small under low load conditions. can.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the slip control device of the present invention, Fig. 2 is a system diagram showing an embodiment of the slip control device of the present invention, and Fig. 3 (1) and (b) are the slip control device of the present invention. A time chart showing changes in the tutee outputted by the control computer, Fig. 4 is a change characteristic diagram of the control pressure for the tutee, Figs. 5(a) and 5(b) are diagrams each explaining the operation of the slip control valve, Fig. 6 is a characteristic diagram of changes in lock-up pressure with respect to duty, Fig. 7 is a block diagram of a computer for slip control, Fig. 8 is a flowchart showing the control program of the computer, and Fig. 9 is a slip control according to the present invention. FIG. 10 is a time chart showing the change rate of the slip amount with respect to the tutee, and FIG. 11 is a time chart showing the slip control situation by the conventional device. 1... Power source 2... Torque converter input element 8... Torque converter output element 4... Clutch 5... Clutch control means 6...
Load detection means 7... Coupling force control constant changing means lO.
...Engine (power source) 11...Crankshaft 12...Flywheel 18...Torque converter 18a...Pump impeller (input noble) 18b...
Turbine runner (output element) 14...Torque converter output shaft 17...Oil pump 21...Radiator 22...
Lock-up clutch (clutch) 25...Slip control valve 28...Control pressure generation circuit 29...Solenoid valve
81... Slip control computer 82... Gear position cage sensor 38... Engine rotation speed sensor 84... Transmission output rotation speed sensor 35... Throttle opening sensor 36... Microprocessor unit 87 ...Read-only memory 38...Input/output interface circuit 39...Converter 4o...Shaping shaping circuit 41...Amplifier 42
...gear transmission mechanism. Fig. 3 Fig. 4 Cytonoid Kaji5-ti (%) Fig. 5 (a) (b) Fig. 6

Claims (1)

[Claims] 1. An input element driven by a power source, an output element driven by hydraulic oil stirred by the input element, and a clutch that appropriately limits the amount of slip between these input and output elements. In the slip control torque converter, the slip control torque converter is provided with a clutch control means for controlling the coupling force of the clutch according to a control constant to bring the slip amount to a set value, load detection for detecting a load state of the power source. 1. A slip control device for a torque converter, comprising: means for controlling a coupling force control constant; and a coupling force control constant changing means for changing the control constant according to a load condition signal from the means. 2. The slip control device for a torque converter according to claim 1, wherein the load detection means detects the load condition from the throttle opening of the power source and the rotation speed of the output element.