JPS60143267A - Controller for slip of torque converter - Google Patents

Abstract

PURPOSE:To enable stable control of slip, by a method wherein a control gain is varied according to the temperatue of clutch working fluid. CONSTITUTION:A temperature detecting means 6 which detects the temperature of clutch working fluid and a control gain varying means 7 which varies the control gain of a clutch control means according to temperature are provided, and the control gain is varied in response to the temperature of the clutch working fluid. This enables the control gain to be always varied to a proper value even if the answering lag of a fluid pressure working system is differed due to a difference in temperature, and permits stable control of slip which is prevented from the occurrence of high hunting.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field The present invention relates to a slip control device for a torque converter used by being inserted into a power transmission system such as an automatic transmission.

(2) Prior art In a normal torque converter, the output element (turbine runner) is rotationally driven via the working fluid from the input element (pump impeller) which is rotationally driven by the power source, so it has the ability to increase torque and absorb torque fluctuations. Although it is convenient because it can perform its functions, relative rotation (slip) between input and output elements cannot be avoided, resulting in poor power transmission efficiency.

Therefore, although torque fluctuations are still a slight problem, some so-called slip control type torque converters are used to maintain the above-mentioned slip at the minimum setting value necessary to absorb torque fluctuations without the need for a torque increase function. It is put into practical use. This type of torque converter usually includes a clutch (lock-up clutch) whose coupling force is adjusted by fluid pressure.
This makes it possible to control each slip between the input and output elements, but this control usually employs PID control according to the deviation between the slip amount and the set value, which improves control stability. The control gain that satisfies the response and responsiveness is determined by experiments and calculations.On the other hand, since the above-mentioned clutch is a fluid-operated thread, a delay in response to operation cannot be avoided, and this delay in response may be caused by the temperature of the fluid. -Different. In other words, when the fluid temperature is low, the viscosity is high, so the response delay becomes severe, and as the fluid temperature increases, the viscosity decreases and the response delay becomes small.

By the way, since the setting of the control gain is performed assuming the fluid temperature, at this assumed temperature, the slip amount is stably brought to the set value without large hunting as shown by the dashed line in Fig. 18. However, when the fluid temperature is lower than this, the response delay described above becomes large and the control gain becomes too large. For example, as shown by the solid line in Fig. 18, the slip wind greatly hunts and reaches the set value. This results in poor control stability.

In this case, it takes a long time for the slip amount to stabilize at the set value, and during this time the power transmission function of the torque converter becomes unstable, causing vibration in the worst case.

(3) Purpose of the Invention From this point of view, it is an object of the present invention to solve the above-mentioned problems by not making the control gain constant, but by making it variable so as to be optimal depending on the temperature of the clutch working fluid.

(4) Structure of the Invention For this purpose, the present invention has a fluid pressure of 1 as shown in FIG.
Input/output element 3 via clutch 2 whose coupling force is adjusted by
In the slip control type torque converter, the slip control type torque converter is provided with a clutch control means 5 which is adjusted to a G level so as to be able to control the slip amount between 4 and 4 to a set value. It is characterized by being provided with control gain changing means 7 for making the control gain of the control means 5 variable. - (5) Examples Examples 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 a military automatic transmission which is to be controlled by the slip control device. is a torque converter, and 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 13 has a pump impeller (input element) Xaa which is drive-coupled to the crankshaft 11 via the flywheel 12 and is constantly driven by the engine. The turbine runner 13. b is drivingly connected to the output shaft 14, and the stator 13C is connected to the hollow fixed shaft 16 via the one-way clutch 15. The working fluid is supplied through the return path 1.
9 and returns to the reservoir 20, where it is cooled by a radiator 21 installed somewhere along the way.In addition, a pressure holding valve (not shown) is inserted in the return path 19, which makes up the inside of the converter chamber. Pressure below the value (1 inverter pressure)
The pump impeller 13a driven by the engine stirs the internal working fluid as described above, causes it to collide with the turbine runner 13b, and then flows through the stator 130. During this time, the turbine is heated under the reaction force of the stator 18Ci. Rotate the runner tab while increasing the torque. During operation in such a converter state, the torque converter 13 can transmit the power of the engine IO to the output shaft 14 while suppressing vibration and increasing torque while generating slip (relative rotation) between the input and output elements 13a and 13b. The power from the output shaft 14 is changed in speed by the gear transmission mechanism 42 to rotate the drive wheels of the vehicle, thereby allowing the vehicle to travel.

The torque converter 13 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 clutch 22, which sets the lock-up chamber 24 so as to be axially movable on this shaft, is connected to the converter L according to the lock-up pressure P in the lock-up chamber 24.
/u Converter pressure P in chamber 18d. The input/output element 13a moves to the left in the figure due to the pressure difference between the input and output elements 13a.

Torque converter 1 by drivingly coupling between 13b
3. Slips may be restricted and canceled.

The lock-up pressure P is controlled by the slip control valve L/u 25 as described below, and for this purpose the lock-up chamber 24 is communicated with the boat 25a of the slip control valve 25 through the hollow hole of the shaft 14 and the circuit 26. valve 25
A boat 25b to which the converter pressure Po is guided by a circuit 27 and a drain port 250 are separately provided, and when the spool 25d is in the neutral position shown, the boat 25a is connected to both ports 25b.

When the spool 25d moves to the left in the drawing, the boat 25a is connected to the boat 25b, and when the spool z5d moves to the right in the drawing, the boat 25a is connected to the boat 250. Converter pressure P that acts on the pressure receiving area difference of the spool land.

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 control pressure P acting on the left end surface of the spool in the chamber 25g.
In response to the force exerted by 8, the control pressure Ps is generated by the control pressure generation circuit 28 and the solenoid valve 29 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 one end 28a (IIF
Then, this line pressure is drained from the other end 2sb of the circuit 28 via the orifice 28C228d. By determining this drain amount by the duty-controlled solenoid valve 29,
A control pressure P8 can be created between the orifices 28C2zsd, which is guided by the circuit 30 to the chamber 25g.

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 plunger 29a is deenergized, the plunger 29a is pushed away by the drain working fluid from the drain opening end 28b, allowing the above-mentioned drain, and when the strain/id 29b is energized, the plunger 29a is moved to the left, thereby opening the drain opening end 28b. shall be closed. 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). Therefore, as shown in FIG. 3(a), when the duty (ch) is small, the time for the solenoid valve 29 to close the drain opening end 28b is short, and therefore the control pressure P8 is
As shown in the figure, it is a constant value determined only by the difference in pressure receiving area between the orifices 28C and 28d. Duty (chi) is the 8th
4), the solenoid valve 27 closes the drain opening end 28b for a long time, so the control pressure Ps gradually increases as shown in FIG. 4, and finally the line pressure P
becomes equal to L.

In FIG. 2, as the control pressure Ps increases, this control pressure causes the spool z5d to move to the right as shown in FIG.
The lock-up pressure P decreases.

L/u On the other hand, as the control pressure P8 decreases, the spool 25d moves to the left as shown in FIG.
is gradually increased, and the lock-up pressure P increases. By the way, since the control pressure PS increases as the duty (%) increases as shown in Fig. 4 L/u, the lock-up pressure P rises as the duty (%) increases as shown in Fig. 6 L/u. . It is kept equal to , decreases as the duty (%) increases, and is finally changed to zero.

The slip control computer 31 is operated by the power supply +■, and receives a torque converter working fluid temperature signal ST1 from the temperature sensor 32 which functions as a temperature detection means.An engine rotation speed (rotation speed of the input element 18a) signal 5ir1 from the rotation speed sensor 88. The gear transmission mechanism from the rotation speed sensor 34 (
4z) Output rotational speed (the rotational speed of the output element 13b is equal to this rotational speed by changing the gear ratio of the gear transmission mechanism 42) signal S.

r and a signal S regarding the gear position (gear ratio) of the gear transmission mechanism 42 from the gear position sensor 85, the duty control of the electromagnetic valve 29 is performed as described below.

For this purpose, the computer 31 is, for example, a microcomputer as shown in the block diagram in FIG. This microcomputer consists of a memory (ROM) 37, an input/output interface circuit (Ilo) 38, and an A/D converter 39.
Waveform shaping circuit 40
The signal ST from the sensor 32 is converted into a digital signal by the A/D converter 39 and inputted, and the signal S5 from the sensor 35 is inputted as is, and based on these input signals, Figures 8 to 11
The control program shown in the figure is executed to duty-control the solenoid valve solenoid 29b via the amplifier 41.0 FIG. 8 shows a background routine, and this routine starts when the ignition switch of the engine 10 is turned on in step 50. executed repeatedly. First, in step 51, the initial values of the MPU 36 and l1088 are set (initialized), and in the next step 52, various signals "T#"ir+5Ort Sg are read. In step 53, it is determined from the signal S whether the gear transmission mechanism 42 has selected the second speed or the eighth speed (since the slip control of the present invention is not performed in the first speed, here speed shall not be determined)0
In the case of second gear, the gear flag GEA is set in step 54.
RFLC is reset to 0, and this gear flag is set to 1 in the case of 3rd speed. In the 0th order, the control proceeds to step 56, where it is determined by the signal ST whether the torque converter working fluid temperature is higher or lower than the set temperature. If the temperature is high, the temperature flag TEMPFLG is set to 1 in step 57, and if the temperature is low, this flag is reset to 0 in step 58. In the next step 59, the signal Si
The 0 signal Sir, which calculates the engine speed NE by executing the interrupt routine shown in FIG. 9(a) based on r, corresponds to the ignition signal of the engine 10 as shown in FIG. Noise is removed by the shaping circuit 40, as shown in FIG. 9(b).
As shown in the figure, a rectangular wave signal Si rises every time the ignition signal is input.
It becomes r'. The interrupt routine in FIG. 9(a) uses the signal Sir
First, in step 70, the rising edge of the signal Sir is read, and in the next step 71, the period T is measured from the time difference with the previous reading, and the engine rotation speed NF is calculated from this period. Control then proceeds to step 72 where the background routine of FIG. 8 is returned.The next step 60 in FIG. First based on r
0 Execute the interrupt routine in Figure (a) to create a gear transmission! g4
2 output rotation speed N. 0 signal S to calculate. r is the 10th frequency corresponding to the output shaft rotation speed of the gear transmission mechanism 42;
This signal is a sine wave signal as shown in FIG.
is triggered by a rectangular wave signal S shown in FIG. r'
The interrupt routine of FIG. 10(a) is executed by the signal S. r
' starts at each rising edge of signal S.
. The rising edge of r' is read, and in the next step 81, the period T is measured from the time difference with the previous reading, and the gear transmission mechanism output rotation speed N is determined from this period. After calculating 0, control proceeds to step 82, where it returns to the background routine of FIG.

In the next step 61 in FIG. 8, the rotational speed N is determined. The torque converter output rotation speed (turbine runner 13b
After that, the control returns to step 52 and the background routine is repeated.

FIG. 11 shows a regular interrupt routine for slip-controlling the torque converter 18, which is executed every 100 ms, for example, when the count value A of the counter 1 in step 90' reaches the set value. Therefore, counter 1 is 10f'rLS
If the count value A is counted up every time, the interrupt routine shown in FIG. 11 is executed every time the count value A reaches 10. Therefore, first, in step 91, it is determined whether or not the count value A is the set value 10. If not, the counter l is incremented by one step in step 92, and the output duty D is increased in the next step 98. The previous calculation duty value D (OLD) is set, and step 94
The process returns to the background routine shown in FIG.

By the way, when the count value A reaches the set value lO, step 91 selects step 95, where the count value A of counter 1 is cleared to O, and in the next step 96, it is determined whether the gear flag GEARFLG is 0 or l. do. When this flag is 0, that is, when the second speed is selected as described above, step 97 is selected as not to perform the slip control of the present invention, as in the case of selecting the first speed, and in this step, the output duty D Rub it 0φG. At this time the 6th
As is clear from the figure, the lock-up pressure "L/u" is made equal to the converter pressure P. By releasing the clutch 22, the torque converter 13 can function as intended in the converter (0/V) state. In the case of , that is, when the third speed is selected as described above, step 96 selects step 98, and in this step 98, the output rotation speed N of the gear transmission mechanism 42 (corresponding to the vehicle speed) is determined as the set rotation speed. Determine whether or not the speed is equal to or higher than N.S (set vehicle speed).If No≧NQS, the torque increasing mechanism and torque fluctuation absorbing function of the torque converter 4 are required to the maximum, so the output duty D is set to 0 in step 97'. %, torque converter 1
3 to function in the converter state.

If No≧No8, step 98 selects step 99, where it is determined whether the engine rotation speed (the rotation speed of the pump impeller 13a) NF is greater than or equal to the rotation speed N7 of the turbine runner 13b. , engine 1
Coasting (engine braking) where 0 is driven in reverse
Since the vehicle is in a running state, slip control of the torque converter 13 should not be performed, so step 97 is performed in this case as well.
By selecting , the torque converter 13 is made to function in the converter state. Note that the control after step 97 is performed in step 9.
Step 4 then returns to the background routine of FIG.

The determination result in step 98 is N. ≧NoS and if the determination result in step 99 is N E > N T, that is, the torque converter 13 is subjected to slip control.
If the operating range is , the control proceeds to step 100, where it is determined whether the temperature flag TEMPFLG is 0 or 1.
In other words, it is determined whether the torque converter working fluid temperature is low or high. If the temperature is low, step 101 is selected, and if the temperature is high, step 102 is selected, and step 10 is selected.
1, the proportionality constant K of integral control in PI control, which will be described later.
i and the proportional constant Kp of proportional control (these determine the control gain of PI control) are small constants for low temperatures.

In step 102, Kp is set to large constants K 1 and K 2 for high temperature, respectively.

iHpH Next, the control proceeds to step 108, where the slip amount N5 (N
s-NE-NT) is smaller than the slip amount set value NR, that is, whether the torque converter 13 is in an insufficient slip state or an excessive slip state with respect to the set value NR.

If there is insufficient slip, D in step 104.
After determining the duty D (NEW ) for integral control by calculating (NEW )=D(OL'D)- as □・ΔX (where Δx is a proportional constant, Δx=lNs-NR1), step 105 is performed. iTD=D (NEW)-K
The final output duty D is determined by taking into consideration the proportional control calculation p-ΔX (where Kp is a proportional constant). Thereafter, in step 106, the previous output duty D (○LD") is exchanged by 1 with the current output duty D, and this is supplied to the solenoid 29b of the electromagnetic valve 29 via the amplifier 41 in FIG. 7 to control the duty. However, since this control reduces the output duty by an amount proportional to the constants Ki and Kp according to the slip error ΔX, the lock-up pressure "L"
As is clear from FIG. 6, /u is gradually increased each time the control is repeated.

Therefore, the lock-up clutch 22 in FIG. 2 weakens the drive coupling between the torque converter input/output elements 1.8a and 13b, and the torque converter 18 is corrected for the lack of slip and brought to the target slip amount NR. Ru.

By the way, in the case of excessive slip, step 1 (M+
selects steps 107 and 108 sequentially, and in these steps calculates the final output duty D in the opposite direction to that in steps 104 and 105. In step 106, this output duty D and the previous output duty D (OLD) are calculated. Replace with. However, in this case,
Since the output duty is increased by an amount proportional to the constants Ki and Kp according to the slip error ΔX, the solenoid valve 29 whose duty is controlled by this increases the lock-up pressure PL/
As is clear from FIG. 6, u is lowered. Therefore, the lock-up clutch 22 is the torque converter input/output element t.
Strengthen the drive coupling of aa and 1abi, and torque converter 1
8 is corrected for the above-mentioned excessive slip, and the target slip amount NR
It will be brought to

After step 106, step 94 is executed to return to the background routine of FIG. 8, but each time the scheduled interrupt routine of FIG. 11 is executed, the torque converter slip amount is brought to the set value NR in sequence. The P-manufacturing is controlled as described above.

By the way, in the present invention, the proportional constants Ki and Kp are changed according to the temperature of the torque converter working fluid so that the control gain determined by these is just right.
Regardless of whether the fluid temperature is high or low, the slip amount can be quickly stabilized at the set value NR without having to greatly hunch-jig the slip amount, as shown in FIG. 12, for example.

In the example described above, only two types of Kp can be changed depending on whether the torque converter working fluid temperature is higher or lower than one set temperature, Q or the proportional constant.
, Kp can be continuously changed according to the torque converter working fluid temperature, and in this case, the control gain can be changed more precisely.

(6) Effects of the Invention Thus, since the slip control device of the present invention has a configuration in which its control gain can be changed according to the temperature of the torque converter working fluid, the response delay of the slip control fluid pressure operating system differs depending on the temperature. The control gain can always be kept at an appropriate value, enabling stable slip control without causing large hunting, and the torque converter slip amount can be quickly stabilized at the set value without causing vibration. .

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing 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 is an explanation of the duty output by the slip control computer in the device of the present invention. Figure 4 is a change characteristic diagram of control pressure with respect to the same duty. Figures 5 (a) and 5 (b) are diagrams explaining the operation of the slip control valve. Figure 6 is a change characteristic diagram of lock amplifier pressure with respect to output duty. 7 is a block diagram of the slip control computer; FIG. 8, FIG. 9(a), FIG. 10(a), and FIG. 11 are flowcharts showing the control program of the slip control computer, respectively; 9(b) and 10) are explanatory diagrams of waveforms before and after waveform shaping of the engine rotational speed signal and the gear transmission mechanism output rotational speed signal, respectively. FIG. 12 is a complete chart of the operation of slip control by the device of the present invention. , FIG. 13 is an operation time chart of slip control by a conventional device. 1... Clutch operating fluid pressure 2... Clutch 8... Torque converter input element 4... Torque converter output 43 element 5 - Clutch control means 6... Temperature detection means 7... Control gain changing means lO... - Engine 11... Crankshaft 12... Flywheel 13... Torque converter 18a... Pump impeller (torque converter input element) 18b... Turbine runner (torque converter output element) - 14. Torque converter output shaft 17.・Pump 21 ・Radiator 22 ・Lock-up clutch 25 ・Slip control valve 28 ・Control pressure generation circuit 29 ・Solenoid valve 81 ・Slip control computer 82 ・Temperature sensor (temperature detection means) ) 33 - Engine rotation speed sensor 34... Output rotation speed sensor 35... Gear position sensor 36... Microprocessor unit 37... Read-only memory 38... Input/output interface circuit 89... A/D converter 40 ...Waveform shaping circuit 41...Amplifier 42...Gear transmission mechanism Fig. 1 Fig. 3 Fig. 4 Solenoid 'Measure C%' Fig. 5 (a) (b) Fig. 6-j ≧-T (%), -L gutter Robek-Kade)〉Toichiko →〉Kokogugu-Tobe? goose

Claims (1)

[Claims] L. In a slip control torque converter equipped with a clutch control means capable of controlling the amount of slip between input and output elements to a set value via a clutch whose coupling force is adjusted by fluid pressure, the temperature of the fluid is detected. A slip control device for a torque converter, comprising: temperature detection means; and control gain changing means for varying the control gain of the clutch control means in accordance with the temperature.