JP2611749B2 - Line pressure control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 shift.

[0002]

2. Description of the Related Art In an automatic transmission, various friction elements (clutches, brakes, etc.) of a transmission gear mechanism are selectively hydraulically actuated by a line pressure to select a predetermined shift speed and to change the friction element to be actuated. 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 transient engagement capacity of the friction element becomes excessively small and the friction element slips. As a result, the life is shortened.

[0003] Therefore, it is necessary to appropriately control the line pressure. Conventionally, for example, "Automatic Transmission RE4R01A" issued by Nissan Motor Co., Ltd. in March 1987.
The line pressure is controlled by determining the drive duty of the line pressure control solenoid based on the engine throttle opening based on the different table data during shifting and during non-shifting, as described in the “Model Maintenance Manual” (A261C07). Was.

However, in such a conventional line pressure control device, when the line pressure control solenoid has a variation in the product, when the characteristics change over time, or when the friction element has a variation in the product, the friction has a problem. In the case of the former, the line pressure deviates from the proper value even with the same solenoid drive duty, and in the latter case, the line element is appropriately controlled for the friction element even if the line pressure is controlled as intended. In any case, the shift shock or the shortening of the life of the friction element can be considered due to excessive or insufficient line pressure.

[0005] As shown in FIG. 11 FIG example, an automatic transmission of the document by a reduction in engine throttle opening degree upshift from the first speed to the second speed to OFF from ON shift solenoid instant t ₁ Looking at the case, if the line pressure is low, the second speed selection pressure, which is based on the line pressure, rises as shown by the solid line to engage and advance the corresponding friction element, and the input / output rotation speed ratio N _{T of the} transmission gear mechanism. The gear ratio represented by / N _O (N _T : input rotation speed, N _O : output rotation 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 to the solid line. In contrast, when the line pressure is high, the operation waveform becomes as shown by the dotted line. Therefore, it can be determined from the time during which the gear ratio N _T / N _O is changing, that is, the inertia phase time T ₂ , whether or not the line pressure is an appropriate value in consideration of the above-mentioned variation and aging.

From this point of view, the present applicant has previously filed Japanese Patent Application No. 62-3
In No. 27452, the input rotation speed and the output rotation speed of the transmission gear mechanism of the automatic transmission described above are detected by the input rotation sensor and the output rotation sensor, respectively, and the inertia phase time is determined based on signals from those sensors. The measuring means
A line that measures the time during which the gear ratio represented by the ratio between the input and output rotation speeds is changing, and controls the line pressure during shifting so that the inertia phase time becomes a target value. A pressure control device has been proposed, which can constantly perform line pressure control in line with the actual conditions of automatic transmissions, and can reduce the occurrence of large shift shocks and shortening of the life of friction elements due to excessive or insufficient line pressure. Can be avoided.

[0007]

However, the inventors of the present application have found the following points to be improved while further studying the above-mentioned apparatus. That is, the apparatus determines excess or deficiency of the line pressure during shifting from the length of the inertia phase time T _2, the inertia phase time T ₂
For example, when an upshift is performed in a state where the throttle opening is a certain degree or more, a large change corresponding to a change in line pressure as shown in FIG. 9 is obtained, but the upshift is performed in a state where the throttle opening is extremely small. 1 is performed because the transient pressure capacity of the frictional element is small and the line pressure is controlled to be significantly lower.
As shown by 0, only a very small change is shown with respect to the change in the line pressure. Because of this, in the above-mentioned conventional device,
In the latter case, it is difficult to accurately determine whether the line pressure is excessive or insufficient, so that the learning control of the line pressure cannot be performed sufficiently properly.

On the other hand, the time associated with the shift is
Other inertia phase above time T ₂ for example, the time from an instruction of change of the friction element to change the gear ratio is completed, i.e. there is a total shift time T _1, the total shift time T ₁ is
Even in the latter case, since the time until the actual engagement of the friction element is started varies depending on the line pressure, etc., as shown in FIG. 9 and FIG. Changes greatly in response to changes in The present invention has been made in view of the above circumstances, and provides an apparatus that advantageously solves the above-described problems.

[0009]

As shown in FIG. 1, a line pressure control device for an automatic transmission according to the present invention selectively hydraulically operates various friction elements of a transmission gear mechanism by a line pressure to set a predetermined gear position. The input rotation sensor and the output rotation sensor of the transmission gear mechanism of the automatic transmission configured to perform the shift to another gear by selecting and operating the friction element to be operated, respectively. The inertia phase time measuring means measures the inertia phase time, which is the length of the inertia phase in which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and the line pressure adjusting means The line pressure is adjusted based on the correction amount data, and the inertia phase time of the next shift is set to the target value using the measured value of the inertia phase time. To correct the correction amount data, the line pressure control device for an automatic transmission, during the speed change,
Throttle opening average output means for detecting and outputting a value obtained by averaging the throttle opening immediately after determining that a shift is necessary and the throttle opening immediately after the end of the inertia phase, and the throttle opening average output means The average value of the throttle opening at the time of shifting is set to a throttle opening at which the change in the inertia phase time with respect to the change in the line pressure is not large enough to correct the correction amount data. A correction amount data correction limiting unit that allows the line pressure adjusting unit to correct the correction amount data using the measured value of the inertia phase time during the shift only when the reference amount is equal to or more than the reference value. It is characterized by becoming.

[0010]

In such a device, the transmission gear mechanism selectively hydraulically operates various frictional elements by the line pressure to select a predetermined gear, and to increase / decrease the supply power at this gear to output. The speed change gear mechanism is shifted to another speed by changing the friction element that is hydraulically operated. During this time, the input rotation sensor and the output rotation sensor detect the input rotation speed and the output rotation speed of the transmission gear mechanism, respectively. The inertia phase time measuring means measures an inertia phase time which is a length of an inertia phase in which a gear ratio represented by a ratio between the input and output rotational speeds is changing. The line pressure is adjusted based on the correction amount data, and the correction amount data is corrected using the measured value of the inertia phase time so that the inertia phase time of the next shift becomes a target value.

On the other hand, the throttle opening average value output means comprises:
At the time of the shift, a value obtained by averaging the throttle opening immediately after determining that a shift is necessary and the throttle opening immediately after the end of the inertia phase is detected and output. Based on a signal from the opening average value output means, the average value of the throttle opening during shifting is large enough that the change in the inertia phase time with respect to the change in line pressure is sufficient for correcting the correction amount data. Only when the reference value is equal to or greater than the reference value set for the throttle opening to be lost, the line pressure adjusting means is allowed to correct the correction amount data using the measured value of the inertia phase time during the shift.

Therefore, according to this device, even if the line pressure control element or the friction element has a product variation or changes over time, the line pressure control taking into account the individual differences of these automatic transmissions and the change over time can be performed. It is possible to avoid the occurrence of a large shift shock due to excessive or insufficient line pressure and to reduce the life of the friction element.In addition, the average value of the throttle opening at the time of shifting is determined by the change in the inertia phase time with respect to the change in line pressure. Only when the change is equal to or greater than a reference value set for the throttle opening degree at which the change is not large enough to correct the correction amount data, the correction amount data for adjusting the line pressure is obtained by measuring the inertia phase time. The throttle opening range is such that the change in the inertia phase time with respect to the change in line pressure is small even when the throttle is open. Using the measured value during shifting in and give prevented sufficiently appropriate and is a no possibility learning, can makes it always proper to control the line pressure.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a power train control system of an automobile incorporating a line pressure control device according to an embodiment of the present invention, wherein 1 is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, Is a drive wheel.

The engine 1 has an engine control computer 5 which has an engine speed N _E
, A signal from a vehicle speed sensor 7 for detecting a vehicle speed V, a signal from a throttle sensor 8 for detecting an engine throttle opening TH, and an intake air amount for detecting an engine intake air amount Q. A signal or the like from the sensor 9 is input. 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 has a fuel injection pulse width T
The fuel is supplied in an amount corresponding to _P, and operation is performed by burning this fuel in time with the rotation of the engine.

The automatic transmission 2 includes a torque converter 10
And a transmission gear mechanism 11 in tandem, and inputs engine power to an input shaft 12 via a torque converter 10. The input rotation of the transmission to the shaft 12 is accelerated and decelerated according to the selected shift speed of the transmission gear mechanism 11, reaches the output shaft 13, and reaches the drive wheels 4 from the output shaft via the differential gear 3 to drive the vehicle. Can be.

Here, the transmission gear mechanism 11 incorporates various friction elements (not shown) such as clutches and brakes for determining a transmission path (gear stage) from the input shaft 12 to the output shaft 13. Is selectively hydraulically actuated by the line pressure P _L to select a predetermined shift speed, and to change to another shift speed by changing the operated friction element. In this case, the shift control computer 14 is used for this shift control.
And a control valve 15.

A computer 14 selectively turns on shift control shift solenoids 15a and 15b in a control valve 15.
And, ON these shift solenoids, Nikki by Tsukasa selectively supplied to the shift control of the line pressure P _L to the various friction elements to shift speed corresponding the combination of OFF is selected. The shift control computer 14 also performs duty control of the line pressure control duty solenoid 16 in the control valve 15 with the drive duty D to obtain the line pressure P _L in the control valve 15 (the line pressure increases as the duty D increases). Control shall be performed as intended by the invention. For the shift control and the line pressure control, the computer 14 receives a signal from the vehicle speed sensor 7 and a signal from the throttle sensor 8 as well as a signal from an input rotation sensor 17 for detecting the rotation speed _NT of the shaft 12 and the like. A signal from an output rotation sensor 18 for detecting the rotation speed N _O of the shaft 13 is input.

The computer 14 is shown in FIGS.
And executes the line pressure control and the shift control. First, a description will be given of the line pressure control program of FIG. 3 which is repeatedly executed by a periodic interruption. In step 20, it is checked whether or not a later-described flag FLAG1 is "1" to determine whether or not shifting is in progress. As a result, if the shift is not in progress (FLAG1 = 0), in step 21, for example, the duty table 1 for non-shift which has been written in the RAM and has the characteristic shown by the solid line A in FIG.
, A table lookup of the line pressure control solenoid drive duty D corresponding to the throttle opening TH is performed, and then the drive duty D is output to the solenoid 16 in step 22 to control the line pressure P _L to a normal value for non-shifting. I do.

On the other hand, as a result of the above check, the gear is being shifted (FLAG1
= 1), the gear position, upshift and
A line pressure control solenoid drive duty D corresponding to the throttle opening TH is obtained from a table look-up from a shift duty table 2 having a characteristic as shown by a dotted line B in FIG. In step 34, it is checked whether or not the shift is an upshift that is particularly likely to cause a shift shock due to an excessive line pressure. In step 22, the drive duty D is output to the solenoid 16 as it is.
On the other hand, in the case of an upshift, in step 25, a line pressure corresponding to the throttle opening TH is written from a correction amount table as shown in FIG. Look up the control solenoid drive duty correction amount ΔD, and then
At 26, D + ΔD is output to the solenoid 16 to control the line pressure P _L to a value for normal speed change.

Next, the shift control and the line pressure control solenoid drive duty correction amount control of FIG. 4 which are also repeatedly executed by the periodic interruption will be described.
Then, it is checked whether or not FLAG1 is 1, that is, whether or not shifting is being performed. If the shifting is not being performed (FLAG1 = 0), at step 31, the vehicle speed V and the throttle opening TH are determined based on a predetermined shifting pattern.
Determine the required gear position corresponding to the combination of
At 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 shift is to be performed as a result, in step 33, FLAG1 = 1 is set so as to indicate that the gear is being shifted, and the solenoids 15a and 15b are turned on and off.
Is changed to execute the shift to the required shift speed, and then the routine proceeds to step 34. Note that this will cause the shifting (FLAG
When 1 = 1), steps 31 to 33 are skipped in the next control.

[0021] At step 34, the timer T ₁ is incremented (increment) for measuring the total transmission time, the next step 35
Then, it is checked whether or not the inertia phase is in progress. In this check, the input / output rotational speed ratio of the transmission gear mechanism 11
It is determined that the inertia phase is in progress while the gear ratio represented by N _T / N _O changes from the gear ratio corresponding to the gear position before the gear shift to the gear ratio corresponding to the gear position after the gear shift. And here, the timer is set in step 36 during the inertia phase.
The T ₂ is incremented (increment) by skipping the inertia phase after step 36, to measure the inertia phase time timer T _2.

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 immediately terminated. At the same time, the flag FLAG2 for executing learning control for correcting the data of the correction amount table in the RAM shown in FIG. 8 is set to 1.

In this manner, while the shift is completed, and thereafter no shift is performed, the control proceeds through steps 30 to 32 to step 39.
However, since FLAG2 is set to 1 as described above, step 40 is selected, and the previous data of the line pressure control solenoid drive duty correction amount ΔD shown in FIG. 8 is corrected and updated by the following learning control.

In step 40, the correction amount correction mode selection subprogram shown in FIG. 5 and the learning control subprogram shown in FIG. 6 are sequentially executed. First, in step 50 in FIG. It is checked whether or not the shift is a shift. If the shift is not an upshift, the learning control is not performed as described above, so the process is terminated. This step 51
Then, what kind of shift was last, for example,
It is checked which of the upshifts is the second to third speed, the second to third speed, and the third to fourth speed, and in the next step 52, it is written in RAM for each type of shift. A value corresponding to the type of shift is read from a certain learning mode selection reference value C described later.

In the following step 53, the throttle opening TH immediately after the shift is determined to be necessary at the time of the immediately preceding shift
_S and the end of the inertia phase immediately after the throttle opening degree TH _e
Obtains the throttle opening average value TH _m on average bets, the next step 54, the throttle opening degree average value TH _m is checked whether smaller than the learning mode selection reference value C, the result if TH _m <C, in step 55, the learning mode selection flag FLAG3, while the FLAG3 = 1 in order to execute the learning control based on the total shift time T _1, TH _m <C
If not, this subprogram is terminated as it is (FLAG3 = 0).

Here, the learning mode selection reference value C is
For example, C = 1/8 in the shift from the first speed to the second speed, C = 2/8 in the shift from the second speed to the third speed, and C = 0 / in the shift from the third speed to the fourth speed. 8 Accordingly, here, the learning mode selection flag FLAG3 is set to 1 when the throttle opening TH is extremely small by executing the subprogram.

Next, here, in step 60 of FIG.
It is checked whether or not FLAG3 = 1, and if FLAG3 is not 1, since the throttle opening TH is not an upshift when the throttle opening is minimal, the line pressure is set to a preferable value in step 61 in order to prevent a shift shock and to reduce the life of the friction element. the corresponding target value of the inertia phase time (shift type and different for each throttle opening) T _2S, as well as looked up from the inertia phase target value table in RAM, which in step 62,
The line pressure control solenoid drive duty correction amount ΔD corresponding to the throttle opening TH is looked up from the correction amount table described above corresponding to the type of the shift, and the inertia phase time T ₂ is set to the target value in step 63. Compare with _T2S .

As a result of the comparison in step 63, T ₂
There When match the T _2S without changing the table data in the RAM of the correction amount [Delta] D, is used as is in the line pressure control during the next shift. When T ₂ > T _2S , the line pressure is too low and the life is shortened due to the sliding of the friction element. Therefore, by executing steps 64 and 65, the correction amount ΔD corresponding to the type of the shift is stored in the RAM. Table data of 0.2
% For use in line pressure control during the next normal shift. Therefore, at the time of the next line pressure control, the line pressure control solenoid drive duty D + ΔD is increased by 0.2% from the previous time, so that the line pressure can be increased by that amount, and the line pressure approaches an appropriate value to avoid a reduction in the life of the friction element. be able to.

Conversely, when T ₂ <T _2S , the line pressure is too high, as shown by the dotted line in FIG. 11, causing a large shift shock due to the excessive engagement capacity of the friction element. The table data in the RAM of the correction amount ΔD corresponding to the type of shift is reduced by 0.2% and used for line pressure control during the next normal shift. Therefore, the line pressure control solenoid drive duty D at the time of the next line pressure control
+ ΔD is reduced by 0.2% from the previous time, so that the line pressure can be reduced correspondingly, and the line pressure can be brought close to an appropriate value as shown by the solid line in FIG. 11 to prevent a large shift shock.

On the other hand, if FLAG3 = 1 in step 60, the shift is performed when the throttle opening is minimum, so in step 67, the total shift time corresponding to the preferable line pressure in the shift when the throttle opening is minimum is determined. The target value (different for each type of shift) T _1S is looked up from the total shift time target value table in the RAM, and in step 68, the correction amount ΔD is looked up from the correction amount table described above, and the total shift time T ₁ compared with the target value T _1S in 69, depending on the result of the comparison, RAM correction amount ΔD in step 70-72 in the same manner as in step 64 to 66 when not throttle opening minimum Increase or decrease or maintain the table data in.

Thereafter, the sub-program is terminated and the process returns to step 41, whereby steps 50 to 71 are skipped until the next shift is completed and learning is permitted. In step 41, the value of FLAG2 and FLAG3 resets the value of the timer T _1, T ₂ is reset to 0 to 0 to wait for the next measurement.

By repeating such an operation (learning control), the line pressure solenoid drive duty correction amount ΔD can be adjusted so that the line pressure control solenoid drive duty D + ΔD during shifting is properly adjusted regardless of individual differences of the automatic transmission and changes over time. (If the throttle opening is not minimum, the inertia phase time T ₂ is continuously adjusted to the target value T _2S ), and the line pressure during shifting is reduced under any circumstances and the life of the friction It can be controlled to an appropriate value that does not cause a shift shock.

Further, according to the apparatus of this embodiment, in the case of a normal upshift, in which the throttle opening TH is not extremely small, the error due to the influence of the operating oil temperature and the like is extremely small, and the gear ratio is actually changed. While the line pressure control is performed based on the inertia phase time, which is the time, while the change in the inertia phase time with respect to the change in the line pressure becomes small due to the upshift with the minimum throttle opening TH, the throttle opening is relatively controlled. Since the line pressure control is performed based on the total shift time that largely changes in response to the change of the line pressure without being affected by the degree, the control of the line pressure can always be made appropriate.

Although the present invention has been described with reference to the illustrated examples, it goes without saying that the present invention is not limited to the above examples.

[0035]

Thus, according to the line pressure control device of the present invention, the average value of the throttle opening at the time of gear shifting is sufficient if the change in the inertia phase time with respect to the change in the line pressure is sufficient for correcting the correction amount data. The correction amount data for adjusting the line pressure is corrected based on the measured value of the inertia phase time only when the throttle opening is equal to or more than the reference value set for the throttle opening, which is not so large. It is possible to prevent learning that may not be sufficiently appropriate using the measured value during shifting in the throttle opening range where the change in the inertia phase time with respect to the change in line pressure is small, and always control the line pressure. It can be done properly.

[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 power train showing one embodiment of the device of the present invention.

FIG. 3 is a flowchart showing a line pressure control and a shift control program of a shift control computer in the same example.

FIG. 4 is a flowchart showing a line pressure control and shift control program of a shift control computer in the same example.

FIG. 5 is a flowchart showing a line pressure control and a shift control program of a shift control computer in the same example.

FIG. 6 is a flowchart showing a line pressure control and a shift control program of a shift control computer in the same example.

FIG. 7 is a characteristic diagram of a line pressure control solenoid drive duty.

FIG. 8 is a diagram exemplifying data in a RAM at a certain moment regarding the correction amount of the same duty;

FIG. 9 is a diagram showing a relationship between a line pressure during a shift and a shift-related time.

FIG. 10 is a diagram showing a relationship between a line pressure during a shift and a shift-related time.

FIG. 11 is a shift operation time chart showing a state of occurrence of an inertia phase during a shift.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronically controlled fuel injection engine 2 Automatic transmission 3 Differential gear 4 Drive wheel 5 Engine control computer 6 Engine rotation sensor 7 Vehicle speed sensor 8 Throttle sensor 9 Intake air amount sensor 10 Torque converter 11 Transmission gear mechanism 14 Transmission control computer 15 Control Valves 15a, 15b Shift solenoid for shift control 16 Duty solenoid for line pressure control 17 Input rotation sensor 18 Output rotation sensor

Claims (1)

(57) [Claims] An automatic transmission in which various friction elements of a transmission gear mechanism are selectively hydraulically actuated by a line pressure to select a predetermined shift speed and to change to another shift speed by changing an operating friction element. An input rotation sensor and an output rotation sensor respectively detect an input rotation speed and an output rotation speed of the transmission gear mechanism of the transmission, and an inertia phase time measuring unit outputs a gear represented by a ratio between the input and output rotation speeds. The inertia phase time, which is the length of the inertia phase in which the ratio is changing, is measured, and the line pressure adjusting means adjusts the line pressure during shifting based on the correction amount data and uses the measured value of the inertia phase time. And correcting the correction amount data such that the inertia phase time of the next shift becomes a target value. During fast, immediately after the shift is determined to be necessary slots
And the throttle opening average value output means for detecting and outputting a value obtained by averaging the slot <br/> Le opening of immediately after the Le opening and the inertia phase, the signal from the throttle opening degree average value output means The average value of the throttle opening during shifting is calculated based on the line pressure.
The change of the inertia phase time with respect to the change
A switch that is not large enough to correct the volume data
A correction amount data correction limiting unit that permits the line pressure adjusting unit to correct the correction amount data using the measured value of the inertia phase time during the shift only when the rotation amount is equal to or greater than the reference value set for the rottle opening. A line pressure control device for an automatic transmission, characterized by comprising: