JP2898642B2 - Line pressure control device for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line pressure control device for an automatic transmission, and more particularly to a device for appropriately controlling a line pressure during a gear shift.

(Prior Art) An automatic transmission is operated by selectively operating various friction elements (clutches, brakes, etc.) of a transmission gear mechanism by a line pressure to select a predetermined shift speed and changing the operated friction elements. The shift to the next gear is performed.

For this reason, if the line pressure is too high, the transient engagement capacity of the friction element becomes excessively large, causing a large shift shock.If the line pressure is too low, the transitional engagement capacity of the friction element becomes excessively small and the friction element slips. As a result, the life is shortened. Therefore, it is necessary to appropriately control the line pressure. Conventionally, for example, as described in “Automatic Transmission RE4R01A Type Maintenance Manual” (A261C07) issued by Nissan Motor Co., Ltd. 6th of each is different depending on non-shift
The line pressure is controlled by determining the drive duty of the line pressure control solenoid based on the engine throttle opening from the table data shown in FIG.

(Problems to be Solved by the Invention) However, in such a conventional line pressure control device,
If there is product variation in the line pressure control solenoid,
When the characteristics change over time, or when the friction element has a variation in the product or when the friction material changes over time, these cannot be dealt with.In the former case, the line pressure will not exceed the proper value even with the same solenoid drive duty. In the latter case, even if the line pressure is controlled as intended, the value may not be appropriate for the friction element, and in any case, excessive shifts in the line pressure and a long life of the friction element are avoided due to excessive or insufficient line pressure. Absent.

The present invention, as shown in FIG. 8, Describing per case of the automatic transmission of the document is Atsupushifuto shifting from the first speed to the second speed OFF the shift solenoid from ON instantaneously t _1,
When the line pressure is low, the second speed selection pressure, which is the base pressure, rises as shown by the solid line to engage and advance the corresponding friction element, and the input / output rotation ratio N _T / N _O (N _T : The gear ratio represented by the input speed, N _O : output speed changes from the first speed equivalent value to the second speed equivalent value as shown by the solid line, and the transmission output torque changes as shown by the solid line. When the line pressure is high, the operation waveform becomes as shown by the dotted line, and the gear ratio _NT / N
From the viewpoint that it is possible to judge whether or not the line pressure is an appropriate value in consideration of the variation and the change with time from the time when _O is changing, that is, the inertia time T, basically, from the viewpoint of FIG. Such a line solenoid drive duty is determined as a basic line pressure for each throttle opening, and the line pressure is controlled to a pressure value obtained by adding a line pressure correction amount for each throttle opening to the line pressure. A line pressure control device is proposed in which the line pressure correction amount is corrected for each throttle opening so that the deviation between the inertia phase time and the target inertia phase time during shifting is reduced.

By the way, in the line pressure control system based on the learning control, if the above-described learning control is continued even while the operating oil temperature of the automatic transmission is high and the control system including the line pressure control solenoid is unstable (cavitation or the like), the line pressure is controlled. Control becomes erratic during this time, and learning control becomes an enemy.

Conventionally, as described in JP-A-63-203948, the operating state of the engine such as the engine load differs from the operating state when the reference value of the shift time (corresponding to the target inertia phase time) is determined. At this time, since the reference value itself is inappropriate, a technique for prohibiting the learning control of the line pressure performed so that the shift time becomes the reference value has been proposed.

However, this technique cannot solve the above-mentioned problem even when the hydraulic oil temperature of the automatic transmission becomes high enough to cause cavitation and the like, and the line pressure control is performed by cavitation and the like due to the high oil temperature. The problem that random learning of the line pressure is performed during the unstable state cannot be completely eliminated.

(Means for Solving the Problems) The present invention particularly aims to propose a line pressure learning control device which does not cause the above-mentioned problem when the automatic transmission has a high oil temperature. As shown in the diagram, various frictional elements of the transmission gear mechanism are selectively hydraulically operated by line pressure to select a predetermined gear position, and change to another gear position by changing the operating friction element. In this automatic transmission, basic line pressure setting means for obtaining a predetermined basic line pressure for each throttle opening of the engine at the preceding stage of the automatic transmission, and a line pressure correction amount for each throttle opening in the basic line pressure. A line pressure adjusting means for adjusting the line pressure to the pressure value obtained by the addition, an input rotation sensor for detecting an input rotation speed of the transmission gear mechanism, and detecting an output rotation speed of the transmission gear mechanism. A force rotation sensor, an inertia phase time measuring means for measuring a time during which a gear ratio represented by a ratio between the input / output rotation speeds is changed, based on signals from these sensors, and an inertia phase time during a previous shift, and A line pressure correction amount correcting means for correcting the line pressure correction amount for each throttle opening so as to reduce the deviation of the target inertia phase time; an oil temperature sensor for detecting a hydraulic oil temperature of the automatic transmission; During a high temperature exceeding a set value, a line pressure learning control prohibiting unit for prohibiting the correction of the line pressure correction amount by stopping the operation of the line pressure correction amount correcting unit is provided.

(Operation) The transmission gear mechanism selectively hydraulically operates various frictional elements based on the line pressure to select a predetermined shift speed, and increases and reduces the supplied power at this shift speed to output. And the transmission gear mechanism,
The gear is shifted to another gear by changing the hydraulically operated friction element.

During this time, the line pressure is adjusted by the line pressure adjusting means to a pressure value obtained by adding a line pressure correction amount for each throttle opening to the basic line pressure for each engine throttle opening set by the basic line pressure setting means. Is done.

On the other hand, the inertia phase time measuring means changes the gear ratio represented by the ratio between the input rotation speed of the transmission gear mechanism detected by the input rotation sensor and the output rotation speed of the transmission gear mechanism detected by the output rotation sensor. Time, that is, the inertia phase time.

The line pressure correction amount correction means corrects the line pressure correction amount for each throttle opening so that the deviation between the inertia phase time and the target inertia phase time during the previous shift is reduced.

As a result, the line pressure is controlled so that the target inertia phase time is constantly achieved.

In other words, even if the line pressure control element has a variation in the product or the characteristics change over time, or if the friction element has a variation in the product or the friction material changes over time, these automatic transmissions can be used. Line pressure control during gear shifting taking into account individual differences and changes over time will be performed, thereby avoiding situations where a large gear shift shock due to excessive or insufficient line pressure or shortening of the life of the friction element is caused. Can be.

By the way, during a high temperature in which the operating oil temperature of the automatic transmission detected by the oil temperature sensor is equal to or higher than the set value, the line pressure learning control prohibiting means stops the operation of the line pressure correction amount correcting means, and the line pressure correction amount is reduced. Prohibit changes. For this reason, during the high temperature, the line pressure control system becomes unstable due to the occurrence of cavitation and the like, and the line pressure control by the learning control is made random. Can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a power train control system of an automobile having a built-in line pressure control device of the present invention, wherein 1 is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, and 4 is driving wheels. .

The engine 1 includes an engine control computer 5,
The computer, the signal from Surotsutorusensa 8 for detecting signals from an engine speed sensor 6 for detecting an engine speed N _E, a signal from a vehicle speed sensor 7 for detecting a vehicle speed V, the engine Ro Tsu Torr opening TH, And a signal from an intake air amount sensor 9 for detecting an engine intake air amount Q. Computer 5 supplies or commands it to the engine 1 determines the fuel injection pulse width T _P on the basis of these input information, a not shown ignition timing control signal to the engine 1. Engine 1 is supplied with fuel in an amount corresponding to the fuel injection pulse width T _P, operated by combusting the fuel in timed with the rotation of the engine.

The automatic transmission 2 includes a torque converter 10 and a transmission gear mechanism.
11 is provided in tandem, and the engine power is input to the input shaft 12 via the torque converter 10. The input rotation of the transmission to the shaft 12 is increased / decreased in accordance with the selected shift speed of the transmission gear mechanism 11 and reaches the output shaft 13 from which the differential gear 3 is rotated.
The vehicle can reach the drive wheel 4 via the vehicle and travel.

The speed change gear mechanism 11 incorporates various friction elements (not shown) such as clutches and brakes that determine a transmission path (gear stage) from the input shaft 12 to the output shaft 13, and these various friction elements are controlled by the line pressure P _L. It is assumed that a predetermined gear position is selected by being selectively hydraulically operated, and a shift to another gear position is performed by changing a friction element to be operated.

For this shift control, a shift control computer 14 and a control valve 15 are provided. The computer 14 is a shift solenoid 15 for shifting control in a control valve 15.
a, 15b are selectively turned ON, and these shift solenoids are turned ON and
Gear position corresponding with a combination of F is selectively supplying the line pressure P _L to the various friction elements to be selected Nikki by Tsukasa shift control. The speed change control computer 14 is additionally provided with a line pressure control duty solenoid 16 in the control valve 15.
Is controlled by the drive duty D to control the line pressure P _L in the control valve 15 (the line pressure increases with an increase in the duty D) as intended by the present invention. A signal from the vehicle speed sensor 7 and a signal from the throttle sensor 8 are input to the computer 14 for the above-mentioned shift control and line pressure control, and a signal from an input rotation sensor 17 for detecting the rotation speed _NT of the shaft 12. And a signal from an output rotation sensor 18 for detecting the rotation speed N _O of the shaft 13 and a signal from an oil temperature sensor 19 for detecting the operating oil temperature TEM of the automatic transmission.

The computer 14 executes the control programs shown in FIGS. 3 to 5 to perform line pressure control and shift control.

First, the line pressure control shown in FIG. 3 which is repeatedly executed by the periodic interruption will be described.
It is checked whether gear shifting is in progress or not depending on whether 1 is 1 or not. If the transmission is not shifting, the line pressure control solenoid driving duty D corresponding to the throttle opening TH is table-up from the non-shifting table data indicated by the solid line A in FIG. 6 in step 21, and then the driving duty is changed in step 22. and it outputs the D to the solenoid 16 to control the line pressure P _L to the normal value for non-shifting.

On the other hand, during the shift, in step 23, the line pressure control solenoid drive duty D corresponding to the basic line pressure for each throttle opening TH is table-up from the shift table data indicated by the dotted line B in FIG. Next, in step 24, the throttle opening is determined from the data of the line pressure control solenoid drive duty correction amount corresponding to the line pressure correction amount for each throttle opening degree as shown in FIG. Line pressure control solenoid drive duty correction amount ΔD corresponding to degree TH
Is read. Then, in step 25, D + ΔD is changed to solenoid 16
And outputs for controlling the line pressure P _L to the value for the shift to.

Next, a description will be given of the shift control and the line pressure solenoid drive duty correction amount control of FIG. 4 which are repeatedly executed by the periodic interruption. First, at step 30, it is determined whether or not FLAG1 is 1 or not.
That is, it is checked whether or not the shift is being performed. If the vehicle is not shifting, the vehicle speed V is determined based on the normal shifting pattern determined in step 31
And the required shift speed corresponding to the combination of the throttle opening TH. In the next step 32, it is checked whether or not the gear should be shifted based on whether or not the requested gear is different from the currently selected gear. If the gear should be shifted, FLAG1 is set to 1 to indicate that the gear is being shifted in step 33, and the solenoids 15a and 15b are turned ON and O.
The shift to the required shift speed is executed by switching the FF. When the shift is being performed, steps 31 to 33 are skipped.

In step 34, the operating oil temperature TEM of the automatic transmission is read, and in the next step 35, it is checked whether or not the inertia phase is being performed. In this check, the transmission gear mechanism 11
The inertia phase changes while the gear ratio represented by the input / output rotational speed ratio N _T / N _O changes from the gear ratio corresponding to the gear before the gear shift to the gear ratio corresponding to the gear after the gear shift. Judge as medium. Then, the timer TM is incremented (stepped) at the step 36 during the inertia phase, and the step 36 is skipped after the inertia phase.
To measure the inertia time.

In the next step 37, it is checked whether or not the inertia phase has been completed (ie, whether or not the shift has been completed). If not, the program is terminated as it is.
Resets the flag FLAG1 to 0 in response to the end of the shift, and sets the flag FLAG2 to 1 for executing the learning control for correcting the RAM data in FIG.

In this way, the shift is completed, and thereafter, while the shift is not performed,
The control proceeds to step 39 through steps 30 to 32. However, since FLAG2 is set to 1 as described above, step 40 is selected, and the previous learning control of the line pressure solenoid drive duty correction amount ΔD shown in FIG. After correcting and updating the data, FLAG2 and timer TM are executed by executing step 41.
Clear

This step 40 is as shown in FIG. 5. First, at step 50, it is checked whether the oil temperature TEM is high, for example, 140 ° C. or higher. If the temperature is not high, the measurement time of the timer TM, that is, the inertia time is checked in step 52. When the inertia time TM coincides with the target value T _S (different for each type of shift and throttle opening) corresponding to a line pressure preferable for preventing shift shock and reducing the life of the friction element, RAM of correction amount ΔD in FIG.
The data is not changed and used for line pressure control during the next shift. When TM> T _S , the line pressure is too low and the life is shortened due to the slip of the friction element. Therefore, by executing step 53, the RAM data of the correction amount ΔD shown in FIG.
% To be used for line pressure control during the next shift. Accordingly, the line pressure solenoid drive duty D + ΔD during the line pressure control is increased by 0.1% from the previous time, so that the line pressure can be increased by that amount, and the line pressure can be brought close to an appropriate value to avoid a reduction in the life of the friction element. Can be. vice versa,
When TM <T _S , the line pressure is too high and a large shifting shock occurs due to the excessive engagement capacity of the friction element. Therefore, by executing step 54, the RAM data of the correction amount ΔD shown in FIG.
% For use in line pressure control during the next shift. Therefore,
The line pressure solenoid drive duty D + ΔD during the line pressure control is reduced by 0.1% from the previous time, so that the line pressure can be reduced by that amount, and the line pressure can be brought close to an appropriate value to prevent a large shift shock.

By repeating such an operation (learning control), the line pressure solenoid drive duty correction amount ΔD changes the line pressure solenoid drive duty D + ΔD during shifting to an appropriate value (inertia) regardless of the individual difference of the automatic transmission and the change with time. Continue to correct the yaw phase time TM to the target value T _S ), and control the line pressure during shifting to an appropriate value that does not cause a reduction in the life of the friction element or a large shifting shock under any situation change. be able to.

If it is determined in step 50 in FIG. 5 that the temperature is high, that is, TEM> 140 ° C., the control is terminated and the RAM data of the correction amount ΔD in FIG. Used for control, prohibits learning control. For this reason, during the high temperature, the system including the line pressure control duty solenoid 16 is unstable and the line pressure control by the learning control is made random, and the random control is performed by prohibiting the learning control. Can be prevented.

(Effects of the Invention) As described above, the apparatus of the present invention is configured to perform learning control of the line pressure during shifting so that the inertia time TM becomes the target value T _S. Even if there is a change, the line pressure during shifting can be maintained at an appropriate value without excess or deficiency, and a large shifting shock and a shortened life of the friction element can be prevented. Further, since this learning control is prohibited during a high oil temperature when the line pressure control system becomes unstable, it is possible to prevent the line pressure control during the high oil temperature shift from being random.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a line pressure control device of the present invention, FIG. 2 is a control system diagram of an automobile para-lane showing an embodiment of the device of the present invention, and FIG. 3 to FIG. FIG. 6 is a characteristic diagram of a line pressure control solenoid drive duty, and FIG. 7 is a momentary RAM relating to a correction amount of the duty.
FIG. 8 is a diagram illustrating data, and FIG. 8 is a shift operation time chart showing a state of occurrence of inertia during a shift. 1 ... electronically controlled fuel injection engine, 2 ... automatic transmission,
3 ... Differential gear, 4 ... Drive wheels, 5 ...
... Computer for engine control, 6 ... Engine rotation sensor, 7 ... Vehicle speed sensor, 8 ... Throttle sensor, 9
…… Intake air amount sensor, 10 …… Torque converter, 11…
… Speed change gear mechanism, 14… speed change control computer, 15…
… Control valves, 15a, 15b… Shift solenoids for speed change control, 16 …… Due solenoids for line pressure control, 17 …… Input rotation sensors, 18 …… Output rotation sensors, 19
... Oil temperature sensor.

Claims (1)

(57) [Claims] 1. An automatic transmission in which various frictional elements of a transmission gear mechanism are selectively hydraulically operated by a line pressure to select a predetermined gear position, and a shift to another gear position is performed by changing an operating friction element. In the transmission, basic line pressure setting means for obtaining a predetermined basic line pressure for each throttle opening of the engine at the preceding stage of the automatic transmission, and adding a line pressure correction amount for each throttle opening to the basic line pressure. A line pressure adjusting means for adjusting the line pressure to the pressure value obtained by the above, an input rotation sensor for detecting an input rotation speed of the transmission gear mechanism, an output rotation sensor for detecting an output rotation speed of the transmission gear mechanism, and these sensors. An inertia phase time measuring means for measuring a time during which the gear ratio represented by the ratio between the input and output rotational speeds is changed, based on a signal from A line pressure correction amount correcting means for correcting the line pressure correction amount for each throttle opening so as to reduce the deviation between the phase time and the target inertia phase time; and an oil temperature sensor for detecting a hydraulic oil temperature of the automatic transmission. An automatic transmission, provided with a line pressure learning control prohibiting means for stopping the operation of the line pressure correction amount correction means and prohibiting the correction of the line pressure correction amount during a high temperature when the hydraulic oil temperature exceeds a set value. Machine line pressure control device.