JPS6060368A - Lock-up controller for torque converter - Google Patents

Abstract

PURPOSE:To prevent the generation of shock and improve fuel consumption by maintaining the perfect connection of a lock-up clutch in deceleration state and gradually restoring the perfect connection from slidable connection in acceleration state. CONSTITUTION:An operation-state monitoring means (f) detects the deceleration state and acceleration state of a prime mover (a) in a lock-up range and operates a lock-up control means (e) so that the perfect connection of a lock-up clutch (d) is maintained in deceleration state and the perfect connection is gradually restored after the slidable connection state of the lock-up clutch (d) in acceleration state. Therefore, the fuel-cut time of the prime mover equipped with a fuel cutting device can be prolonged and fuel consumption can be improved, and the necessary time for the output torque of the prime mover to become a stationary torque can be prolonged, and the generation of shock on acceleration can be prevented.

Description

[Detailed description of the invention]

The present invention relates to a torque converter to be used, and particularly to a lock-up control device for a lock-up torque converter that can appropriately eliminate relative rotation (slip) between its input and output elements. A normal torque converter transmits power by driving an output element (usually a turbine runner) through working fluid stirred by an input element (usually a pump inverter) driven by a prime mover, so it has a torque increasing function and torque fluctuation. Although an absorption function can be obtained, on the other hand, relative rotation between input and output elements called slip cannot be avoided, resulting in poor power transmission efficiency. Therefore, in operating conditions of the prime mover where the torque increase function and torque fluctuation absorption function are not required, the input and output elements are directly connected mechanically using a lock-up clutch. . However, a so-called lock-up torque converter that eliminates the above-mentioned slip in the operating state is being put into practical use. This torque converter is basically operated in the converter state with the lock-up clutch released (converter area of the torque converter) in the operating state of the prime mover where its torque increase function and torque fluctuation g & collection function are required. , the lock-up clutch is operated in the fully engaged lock-up state (the torque converter's Il
1 lockup area). However, in performing this four-up control, the lock-up clutch is always fully engaged in the lock-up region as shown in FIG. 14, and the torque converter is locked up (L/u
) In the deceleration state when the accelerator pedal is released, there is no slip in the torque converter, so the prime mover rotation speed N can be made to a high value NLu, and the output torque of the prime mover is on the negative side. Although the engine brake increases and sufficient engine braking is obtained, the next time you step on the accelerator pedal! The steady torque reaches 1 within a certain period of time, and since the torque difference is large and the change is rapid, it causes a large shock, and in severe cases, the reaction causes long-term vibration, which becomes unbearable. For example, Nissan Motor Co., Ltd. issued maintenance manual No. A2610.
As shown in ``Automatic Transmission'' in No. 04, when the lock-up clutch is released in the deceleration state as shown in Figure 13, the torque converter is temporarily put in the converter (A/T) state, and then the moment of re-acceleration occurs. T
A type of four-up control device has been proposed in which the torque converter is returned to the lock-up (L/u) state by complete engagement of the lock-up clutch at 0.0. In this case, the prime mover rotation 1X number is lower than the prime mover rotation speed Nlu when there is no slip (when the torque converter is in a lock-up state) by the slip amount n□ of the torque converter in the deceleration state before the instant To, and naturally the prime mover output torque (Negative side torque) is also small like KQ. Also, after instantaneous TQ, 2(・(4)) The lock-up clutch is fully engaged, but due to the delay in the response of the hydraulic actuation system, this 1 is actually performed as shown by the two-dot chain line x, and the lock-up clutch is instantaneously engaged. It is not fully coupled until it reaches T1 ◇During this time, the prime mover rotation speed once overshoots by nl, then becomes NLu, and the prime mover output torque also overshoots by the inertial mass of the rotating part of the prime mover due to the overshoot of the rotation speed. However, in such a lock-up control device, the prime mover output torque KQ, which occurs on the negative side in the reduced IO speed state, is smaller than the corresponding torque shown in FIG. 14, and the torque difference KO+ is 1. 1st
It is smaller than the torque difference Ks + Kl in Figure 4, and the instantaneous 'r
The time between o - T1 corresponds to the time lll0-T in Fig. 14.
Since it is longer than 2 and the torque change is gradual, it can solve the shock and vibration problems mentioned above with reference to Fig. 14, but since the torque Ko is small, the effect of the engine braking obtained by this is low. Moreover, if the motor is equipped with a fuel cut device because the rotational speed N is low in the deceleration state, the following problem will occur. In other words, the fuel cut device stops the fuel supply to the prime mover (fuel cut) until the rotation speed of the prime mover falls close to the limit rotation speed at which the prime mover can restart. When it drops further than that. The fuel supply to the prime mover is resumed (fuel recovery) even during deceleration operation, but as mentioned above, if the prime mover rotation speed N is low during deceleration, the fuel must be recovered as quickly as possible, and the fuel cut time is shortened. If this causes a deterioration in fuel efficiency, the concentration of hydrocarbons (HO) in the exhaust gas during deceleration will increase for both the I and 1 engines, which is also disadvantageous in terms of exhaust gas measures. The present invention can solve the problem 15 mentioned above with reference to FIG. 18 by leaving the torque converter in the lock-up state during deceleration in the lock-up region without changing it into the converter state, and when re-accelerating in the same region, the torque converter can be turned into the lock-up state. If the pull-up clutch is brought into a slidingly engaged state, and then the lock-up clutch is gradually fully engaged to return the torque converter to the lock-up state, the problem described in Figure 14 (4) can also be solved. From the viewpoint of solving all of the above-mentioned problems and obtaining ideal lock-up control, it is an object of the present invention to provide a lock-up control device for a torque converter that embodies this idea.For this purpose, the present invention As shown in FIG. 1, the power is directly locked up in the out-rotation state via a transmission path that transmits power from a prime mover a to an output shaft C via a torque converter b, and a lock-up clutch d that is appropriately coupled. A lock-up control device for a torque converter, comprising 15 lock-up control means e, which releases clutch d and fully engages lock-up clutch d in an operating state of prime mover a corresponding to a lock-up region of the lock-up torque converter. The deceleration operating state and the re-acceleration operating state of the prime mover a are detected, and the lock-up clutch d is kept fully engaged in the decelerating operating state, and the lock-up clutch d is kept in the sliding engagement state in the re-accelerating operating state. The present invention is characterized in that an operating state monitoring means f is provided which operates the lock-up control means e gradually so that the lock-up control means e is completely connected after the lock-up is completed. Hereinafter, the present invention will be described in detail with reference to illustrated embodiments. do. FIG. 2 shows an embodiment of the lock-up control device of the present invention together with a four-up torque converter for a vehicle automatic transmission to be controlled by a collector. In the figure, 1 is an engine as a prime mover, 2 is its crankshaft 11° 8 is a flywheel, 4 is a lock-up torque converter, and 5 is a gear transmission mechanism. The torque converter 4 includes a pump impeller (input element) 4a connected to the crankshaft 2 via a flywheel 8 and constantly driven by the engine, a turbine runner (tB77v element) 4b opposed to the pump impeller 4a, and a stator ( The turbine runner 4b consists of 8 elements including the reaction force element) 40.
is drivingly coupled to the output shaft (input shaft of the gear transmission mechanism 5) 7 of the torque converter 4, and the stay &40 is connected to the one-way clutch 8.
Hollow through (8) Place on fixed shaft 9. The torque converter 4 supplies a working fluid to a converter chamber 10 in the direction of the arrow y, and discharges the working fluid in the direction of the arrow. The pressure (converter chamber) in the converter chamber is kept at Pc below the pressure within 1o, and the pump impeller 4a driven by the engine as described above stirs the internal working fluid, collides with the turbine runner 4b, and then flows to the stator 4C. During this period, the turbine runner 4b is rotated IO while increasing the torque under the reaction force of the stator 40. Therefore, the power from the engine 1 is transmitted to the driving wheels via the torque converter 4, the output shaft, and the transmission mechanism 5, and the vehicle can be driven. Also, the torque converter 4 connects the input element 4a and the output element 4b. A lock-up clutch 11 is provided in order to make it a 15-tube type that can be mechanically directly connected as appropriate, and this is drivingly coupled to the output shaft 7 via a torsional damper 12, and is movable in the axial direction on the output shaft. In addition to the converter chamber 10, a p-tuck-up chamber 18 is set inside the torque converter 4.
0ru. The lock-up clutch 11 is in the converter chamber 101
In response to the difference between the converter pressure PC in the interior and the lockup pressure P''/u in the four-up chamber 18, it moves to the left in the figure and drives and connects the input and output elements 4a and 4b with a force corresponding to the differential pressure. The lock-up pressure PL/u is adjusted by the slip control valve 14, which is connected to the boat 14a leading to the four-up chamber 18 and the converter king PC. Boat being run over 1
4b and a drain boat 14c, and when the spool 14d is in the neutral position shown, the bow) 14a is set to both bows) 1
4b and 140, and when the spool 14d moves to the right in the figure, the boat 14a is connected to the boat 14b, and the spool 14d is
When moves to the left in the diagram, 14a to % vine*boat 14C

[・ shall be communicated to each. The spool 14C1 responds to the differential pressure between the lock-up pressure PVu acting on the right end surface in the drawing through the orifice 15 and the control pressure Ps acting on the left end surface in the drawing, and the control pressure Ps is created as follows. That is, the reference pressure (line pressure in the case of an automatic transmission) PL that controls the speed change of the transmission wI5 is supplied from the end 16a of the control pressure generation circuit 16, and this line pressure is passed through the orifice F and 18. By draining from the other end 16b of the circuit 16 and determining the amount of drain by the duty-controlled electromagnetic valve 19, a control pressure ps can be created between the orifices 17 and 18. In normal state, the solenoid valve 19 is closed to the plunger 19 by the spring 19a.
b is moved to the left in the figure to close the drain opening end 16b of the circuit 16, and each time the solenoid IQ id 1oc is energized, the plunger 19b is moved to the rightward position as shown in the figure to open the drain opening end 16b. The above drainage shall be permitted. The solenoid 190 is energized by the lock-up control computer 20 as shown in FIGS. 8(a) and 8.
The duty control is performed so that it is performed during the pulse width (on time) of the pulse signal as shown in FIG. As shown in FIG. 8(a), when the duty is small, the time for the solenoid valve 19 to open the drain opening end 161) is short, and therefore the control EP8 is set to 20 line pressure P as shown in FIG.
Equal to L. Furthermore, as the duty (%) increases as shown in FIG. 18(b), the solenoid valve 19 begins to open the drain opening end 16b for a long time, and therefore the control pressure Ps gradually decreases as shown in FIG. , finally the orifice 17.18
Determined by the difference in aperture area and remains a constant value. In FIG. 2, as the control pressure ps increases, this control pressure causes the spool 14d to move to the right as shown in FIG.
Lock-up pressure PL, /u to "L/u"' = -Ps
(where k is a constant), the pressure increases gradually as shown in FIG. 6, and finally reaches a constant value corresponding to the converter pressure Pc. As the control pressure ps decreases, the lock-up pressure PL/11 increases by 1° at the end face of the spool 14 (l) on the opposite side to which it acts, as shown in FIG.
The boat 14a is made to communicate with the boat 14G by moving to the left as shown in J, and the four-up pressure PL/u is gradually decreased in the same manner as above, and finally reaches zero. Then, the slip control valve 14 has a p pull-up pressure PL/u corresponding to the control pressure Ps, and 2. . When the value is reached, the spool 14d is returned to the neutral position 1 shown in Fig. 2, and the lock-up pressure PL/u is maintained at this value.
This four-up pressure can be controlled by the control pressure Ps. By the way, the change characteristics of the control pressure Ps with respect to the duty (regret) are as shown in Fig. 4, and the control pressure (ps) - lockup pressure ((PL/ll) shown in Fig. 6)
From the characteristics, the change characteristics of the lockup pressure PL/u with respect to the duty size are as shown in FIG. The lock-up control computer 20 is operated by a power source V, and receives a gear position signal Sg1 from a gear position sensor 21 that detects the selected gear position of the transmission mechanism 5. Vehicle speed sensor 22
The vehicle speed signal Sv from the engine 1, the idle signal S from the idle switch 28 which turns on when the accelerator pedal C (not shown) that controls the output of the engine 1 is released, and the engine throttle opening signal from the throttle opening sensor 24. It receives the temperature signal STH and the engine cooling water temperature signal 8w from the water temperature sensor 25, and performs duty control of the electromagnetic valve 1920 based on these calculation results. For this purpose, the computer 0 has a microprocessor unit (MPU) 26, for example, as shown in FIG.
Random access memory (RAM) 27, read-only memory (ROM) 28 (input/output interface circuit)
10) It consists of 29 microphones, four computers, and a user. The MPU 26 is the sensor 21 a 22 #2
4*1101 the signal from 25 and switch 28!
9 and outputs the above calculation result to the drive circuit 80 via 11027.
Since the signal Sv is a pulse signal at 102 o, a counter to count the number of these pulses and a signal 8 are required.
Since TH and Sv are analog signals, A7. to convert them into digital signals. It is assumed that a converter and further a counter for converting the above calculation results into binary values into duty control pulse signals are included. The MPU 26 executes the control program shown in FIG. 9 stored in the ROM 1!8 to turn the solenoid valve 19 on duty! 11, the lock-up pressure PL/u' is controlled according to the duty as shown in FIG. 7, and the operation of the four-up clutch 11 is controlled. FIG. 9 shows the lockup (L/up) M""-chin. This routine is performed at regular intervals of, for example, 100 mB. Executed repeatedly. First, in step 81, by reading the cooling water temperature signal Sw from the sensor 25, it is determined whether the engine cooling water temperature is higher or lower than, for example, 60° C., which is a guideline for completion of continuous warm-up of the engine 1. If it is low, the warm-up operation has not been completed and the engine 1° output torque is unstable, so the control proceeds to step 82, where the output duty (DUTY) is maximized as shown in the diagram, and the lock-up clutch 1] Since the torque converter 54 is released, the torque converter 54 becomes a converter state, and its torque fluctuation absorbing function appropriately absorbs fluctuations in the engine output torque and enables smooth power transmission. If the engine coolant temperature is high, warm-up has been completed and the above-mentioned problem will not occur, so the control will continue. (15) Proceed to step 88. In this step sensor 21.122
．． The operating state of the engine 1 is determined based on the gear position signal to Sg1 from 24 and the throttle opening signal STH, and in the next step 84, the operating state of the lever is determined to set the torque converter 4 to the comparator 1 state. Based on the map corresponding to the lock-up area diagram in FIG. 11, it is determined whether the area is in the A/T area where it should be placed or in the L/U area where it should be in the lock-up state. A7. If the area is in the L/11 area, the torque converter 4 is set to the predetermined condition as described above in step 82, and in step 85 if it is in the L/11 area.
The idle signal Sl from the idle switch 28 at
Based on this, it is determined whether the idle switch 28 is on or off. When the accelerator pedal is released for 1 m, the idle switch 28 is turned on as described above, and at this time step 3
At step 6, the idle flag FLAGID is set to 1. Next, the control proceeds to step 87, where the presence or absence of a shift is detected based on whether there is any change in the gear position signal S. Next step...(16) The knob 88 determines whether or not the gear is being shifted. If the gear is shifting (\1), the control proceeds to step 82, and if it is in the - range, the torque converter 4 is set to the converter state. This prevents shift shock from occurring. If the gear is not being shifted, the control advances from step 88 to step 89, where the output duty (DUTY) is set to 10.
Make it 0 good. At this time, the lock-up pressure PL/u is minimized as shown in FIG. 7, and the lock-up clutch 11 is completely engaged, so that the torque converter 4 can be in a predetermined lock-up state in the negative region. In the acceleration state where the accelerator pedal is depressed, the idle switch 28 is turned off, and at this time step δ5 is changed to step 40.
Select. In step 40, the idle flag FLA
Determine whether GID is 0 or 115. If it is 1, as is clear from the above description of step 86, this means that the vehicle has been re-accelerated this time in the previous deceleration state, and at this time step 40 sequentially selects steps 41 and 42. In step 41, the idle flag FLAGID is reset to 0, and Stella 2
In the 0b 42, the output duty (DUTY) is set to a value between 0qIb and 1100%, for example, as shown by DSET in FIG. As shown in FIG. 7, the duty DSET is an intermediate value between the highest and lowest values of the lock-up pressures PIJ/uOPL/uD, and the 10-' pull-up clutch 11 is engaged while sliding. If it is determined in step 40 that the 7 rack FLAGID is 0, that is, if the acceleration state continues, the control proceeds to step 48, where the output ``'''' duty (D
It is determined whether or not UTY) is 100%. If so, since the torque converter 4 is already in the four-up state, control proceeds to step 89 to maintain this lock-up state. If the output duty is not 100 in step 48,
'll, the output duty (DUTY) is increased by a predetermined amount ΔD in step 44, thereby increasing the coupling force of the lock-up clutch 11 by that amount. Figure 12 shows that the vehicle is temporarily decelerated in the L/u region, and
Below is the operation time chart when accelerating again. Based on this, the operation of the above embodiment will be briefly explained below. In the deceleration state described above, the control proceeds to steps 86 to 89 (provided that no gear change is performed), the output duty is set to 1001, and the lockup puller is activated. The switch 11 is completely connected and the silk converter 4 is left in the four-up (L'/u) state. Therefore, since the torque converter 4 does not slip, the engine speed N is set to the same high value as NLu during this deceleration, and the engine output torque generated on the negative side also increases by 1°, providing sufficient engine braking. Thus, the problem described above with reference to FIG. 18 can be solved. By the way, at the re-acceleration instant To, the control proceeds to step 85.
．． Proceeds to 40 to 42, output duty is 15DSET
will be lowered to Therefore, the lock-up clutch 11 is slidably connected, and the torque converter 4 is changed from a lock-up state to a slip state (but not a converter state). After that, the control goes to step 85*40]
-48e Proceed to 44 (O output duty is DSET
It increases by ΔD from 'f141 and returns to 1001 at T8. During this time, the lock-up clutch 11 gradually increases the coupling force (torque: gradually decreases the inverter slip l,
), to return to the fully connected state at time T8, based on the change in engine speed N. The resulting engine output torque also reaches a steady torque of 1 only after reaching instantaneous T8. Therefore, the time between instants T and -T3 becomes longer, and the change in engine output torque becomes gentler, making it possible to eliminate the gap described above with reference to FIG. Thus, as described above, the lock-up control device of the present invention keeps the torque converter in the lock-up state without changing it to the converter state during deceleration in the lock-up region.
During this time, the engine speed N can be kept high, and the seven-wheel cut time of the prime mover equipped with the fuel cut device 1j can be lengthened, thereby improving fuel efficiency and lowering the concentration of hydrocarbons (HC) in the exhaust gas. Also, during this deceleration, the motor output torque generated on the negative side increases by 2, which improves the effectiveness of the engine brake.
be able to. Furthermore, at the time of re-acceleration in the lock-up region, the torque converter is brought into a state in which the lock-up clutch 11 is slid and engaged, and then the lock-up clutch is gradually fully engaged to return the torque converter to the lock-up state. By lengthening M70-T8 until the torque reaches the steady torque Kl, the change in torque can be made smoother, and it is possible to prevent shocks and vibrations from occurring during the re-acceleration. Therefore, the device of the present invention can perform ideal stomach 10-up control while solving all of the above-mentioned conventional problems. FIG. 10 is a modification of the p-tuck-up control routine shown in FIG. 9. In this example, the routine in FIG.
In contrast to 15 in which 1 is in a sliding connection state, this control is in 7
This is performed only when re-accelerating from a deceleration state where the 7-Yel cut has occurred, and is not performed when re-accelerating from a deceleration state where the 7-Yel cut has not been made. For this purpose, in this example, the fuel cut 7 2 indicates that the fuel is being cut.
'Set FLAGFO and add Nystera 7'45.4111 for step 86.87°. Step 45
Then, it is determined whether or not the engine 1 is in the 7-well cut mode based on a signal (not shown) from the 7-well cut device, and if so, the flag FLAGF is set. 0 is set to 1, otherwise control proceeds to step 87. Furthermore, step 47 is added after step 41, and step 48 is added after step 42, respectively. In step 47, the flag FLAGFO is 1 or 0.
If it is 1, it is F1. . Since this means that the deceleration state has been re-accelerated, the output duty is set to DSET in step 42.
Although the same control as described above for FIG. 9 is carried out,
If FLAGIFO is 0, it means that the vehicle has re-accelerated from a deceleration state without fuel cut. Therefore, in step 89, the output duty is kept at 100, which is the same as during deceleration, and the torque converter 4 is kept in the lock-up state. Note that the flags FI and AGFO are reset to 0 after step 42 is executed. 1 In the lock-up control program of this example, when re-accelerating from a deceleration state in which 1 fuel is not cut, the re-acceleration is performed while the torque converter 4 is kept in the lock-up state, so the output torque of the engine 1 is unstable. Torque 5 converter is DUTY-DS even though it is not
It is possible to prevent the discomfort caused by -H slip due to ET and then a lockup state, during which the rotational speed of the engine 1 fluctuates greatly.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of the lock-up control device of the present invention, FIG. 2 is a system diagram showing an embodiment of the device of the present invention, and FIGS. 8(a) and 8(b) are for lock-up control in the device of the present invention, respectively. Figure 4 is a time chart showing how the duty changes as output by the computer. Figure 4 shows the change characteristics of control pressure with respect to duty. Figures 5 (a) and 5 (b) are explanatory diagrams of the operation of the slip control valve. (2t) (28) Figure 6 is a characteristic diagram of changes in lock-up pressure with respect to control pressure, Figure 7 is a characteristic diagram of changes in lock-up pressure with respect to duty, Figure 8 is a lock-up diagram of the lock-up control computer, Figure 9 10 are flow charts showing two examples of control programs executed by the lock-up control computer, respectively. 1. Operation time chart of the device. FIGS. 13 and 14 are operation time charts showing two examples of the operation time chart of the conventional lock-up control device. 1. Engine (prime mover a) 4.・Lock-up torque converter 5... Gear transmission mechanism 7... Torque converter output shaft (○) (24) 11... Lock-up clutch (CI)] 4... Slip control valve 16... Control pressure Generation circuit 19...Solenoid valve 20...Lockup control computer 21...
Gear position sensor 22... Vehicle speed sensor 28... Idle switch 24... Throttle opening sensor 25...
・・Water wetness sensor 26 ・・Microprocessor unit (MPU) 27
... Random access memory (RAM) 28 ... Read-only memory (ROM) 29 ... Input/output interface [1 (Engineering 10) 80
... Drive circuit b... Torque converter e... Lockup control means f... Operating state monitoring means. JP-A-Sho GG-60368 (8) / Kou 1 0 Aoi Toto Toji J

Claims (1)

[Claims] 1. A converter for a lock-up torque converter that has both a transmission path that transmits power from a prime mover to an output shaft via a torque converter, and a transmission path that transmits the power directly to the output shaft via a lock-up clutch that is appropriately coupled. A lock-up control means is provided which releases the lock-up clutch in an operating state of the prime mover corresponding to the lock-up region of the lock-up torque converter and fully engages the lock-up clutch in an operating state of the prime mover corresponding to the lock-up region of the lock-up torque converter. Torque converter lock-up control device--In this device, the deceleration operating state and re-acceleration operating state of the prime mover in the lock-up region are detected, and the lock-up clutch is kept fully engaged in the decelerating operating state, and the lock-up clutch is kept fully engaged in the re-accelerating operating state. 111 so that the lock-up clutch is brought into a slidingly engaged state and then gradually fully engaged.
1. A lock-up control device for a torque converter, characterized in that it is provided with operating state monitoring means for activating the lock-up control means.