JPH0242264A - Line pressure control device of automatic transmission - Google Patents

Abstract

PURPOSE:To prevent misstudy because the value in power-off condition is included in the measurement of inertia phase time by performing study control only when speed changing is conducted while an automatic transmission does not include power-off condition. CONSTITUTION:A speed change gearing mechanism engages friction elements selectively with the line pressure so as to perform speed changing. At this time, a line pressure adjusting means adjusts the line pressure so that the inertia phase time from speed change start measured by a time measuring means in response to a signal given by an input and an output rotation sensor becomes identical to the target value. A power-off signal output means, on the other hand, emits a signal indicating if the speed change with inertia phase time measured is a speed change including the power-off condition, while a control yes/no judging means allows generation of study control on the basis of inertia phase time only when speed change is made with the power-off excluded. This prevents misstudy and allows conduction of line pressure control during speed changing properly at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a line pressure control device for an automatic transmission, and particularly to a device for appropriately controlling line pressure during gear shifting.

(Prior art) Automatic transmissions selectively hydraulically operate various friction elements (clutches, brakes, etc.) of a transmission gear mechanism using line pressure to select a predetermined gear, and change the friction elements to be operated. Shift to the next gear.

Therefore, if the line pressure is too high, the transient engagement capacity of the friction element becomes too large, causing a large shift shock. If the line pressure is too low, the transient engagement capacity of the friction element becomes too small, causing the friction element to slip. This leads to a decrease in service life. Therefore, it is necessary to properly control the line pressure, and in the past, for example, the "Automatic Transmission RE4R01A Type Maintenance Manual" published by Nissan Motor Co., Ltd. in March 1987 was used.
As described in (^261CO7), the line pressure was controlled by determining the drive duty of the line pressure control solenoid based on the engine throttle opening from different table data during shifting and non-shifting.

However, in such conventional line pressure control devices, when there are product variations in the line pressure control solenoid or changes in characteristics over time, or when there are product variations in the friction elements or when the friction material changes over time. When a change occurs, in the former case, the line pressure deviates from the appropriate value even with the same solenoid drive duty, and in the latter case, even if the line pressure is controlled as desired, it may not be the appropriate value for the friction element. Too much or too little line pressure can cause a large shift shock or shorten the life of the friction elements.

By the way, for example, as shown in FIG.
Looking at the case of upshifting from 1st to 2nd speed by turning the shift solenoid from ON to OFF, if the line pressure is low, the 2nd speed selection pressure, which uses this as the source pressure, increases as shown by the solid line. The gear ratio expressed by the input/output rotational speed ratio Nt/No (A: input rotational speed, No.: output rotational speed) of the transmission gear mechanism is the first.
The speed equivalent value changes to the second speed equivalent value as shown by the solid line, and the transmission output torque changes as shown by the solid line, whereas when the line pressure is high, the operating waveform becomes as shown by the dotted line.

Therefore, from the time during which the gear ratio NT/No is changing, that is, the inertia phase time T, it can be determined whether the line pressure is at an appropriate value taking into account the above-mentioned variations and changes over time.

From this point of view, the present applicant previously applied for patent application No. 62-32745.
In No. 2, an input rotation sensor and an output rotation sensor respectively detect the input rotation speed and output rotation speed of the transmission gear mechanism of the automatic transmission mentioned above, and based on the signals from those sensors, the inertia phase time is determined. The measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and the line pressure adjusting means adjusts the line pressure during the shifting so that the inertia phase time reaches the target value. We have proposed a line pressure control device that can constantly control line pressure in accordance with the actual situation of automatic transmissions, and can prevent large shift shocks and friction caused by excessive or insufficient line pressure. It is possible to avoid shortening the lifespan of the elements.

(Problems to be Solved by the Invention) As the inventors of the present invention conducted further research on the above-mentioned device, they discovered the following points to be improved.

In other words, even if the engine throttle opening is the same, the transient engagement capacity of the friction element of the automatic transmission installed in a vehicle is determined by whether the transmission is in the power-on state where the engine is providing driving force to the automatic transmission or not. Conversely, it differs depending on whether the engine is being shifted in a power-off state, where driving force is supplied from the automatic transmission, and therefore the measured value of the inertia phase time is also the same depending on whether it is in a power-on state or a power-off state. It differs depending on the throttle opening.

However, in the conventional line pressure control device described above, the target value of the inertia phase time is determined only according to the type of shift and the throttle opening in order to be suitable for shifting when the power is on. In this case, learning control would be performed even on the measured value of the inertia phase time when shifting near the fully closed throttle opening, where the power-on state and power-off state alternate, and as a result, the shift shock may be caused. There was a risk that the occurrence could not be sufficiently prevented.

The present invention provides a device that advantageously solves this problem.

(Means for Solving the Problems) The line pressure control device for an automatic transmission of the present invention is as shown in FIG. An input rotation sensor and an output rotation sensor detect the input rotation speed and output rotation speed of the transmission gear mechanism of an automatic transmission that selects a gear and shifts to another gear by changing the operating friction element. Based on the signals from these sensors, the inertia phase time measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and the line pressure adjusting means , a line pressure control device that controls the line pressure during the shifting so that the inertia phase time becomes a target value, a signal indicating whether or not the shifting for which the inertia phase time was measured is a shifting that includes a power-off state; a power-off signal output means for outputting a power-off signal; and a control enable/disable determination means for regulating line pressure control of the line pressure adjustment means during a shift based on the inertia phase time based on the signal from the power-off signal output means. It is characterized by:

(Function) In such a device, the transmission gear mechanism selectively hydraulically operates various friction elements using line pressure to select a predetermined gear position, and outputs the supplied power by increasing or decelerating it at this gear position. The transmission gear mechanism is then shifted to another gear stage by changing the hydraulically operated friction element.

During this time, the input rotation sensor and the output rotation sensor are respectively detecting the input rotation speed and output rotation speed of the speed change gear mechanism. The inertia phase time measuring means measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds of the speed change gear mechanism is changing, that is, the inertia phase time during the speed change, based on the signals from these two sensors. Then, the line pressure adjusting means controls the line pressure so that the inertia phase time reaches the target value.

On the other hand, the power-off signal output means outputs a signal indicating whether or not the speed change for which the inertia phase time was measured is a speed change that includes a power-off state, and the controllability determination means includes:
Based on the signal from the power-off signal output means, learning control based on the inertia phase time of the line pressure adjustment means is regulated.

Therefore, with this device, even if there are product variations in the line pressure control element or changes in characteristics over time, or even if there are product variations in the friction element or changes in the friction material over time, these It is possible to perform line pressure control that takes into account individual differences in automatic transmissions and changes over time, and it is possible to avoid large shift shocks and shortened lifespans of friction elements due to excessive or insufficient line pressure. Since learning control is performed only when the machine shifts gears without including the power-off state, it prevents erroneous learning due to the measured value of the inertia phase time including the value in the power-off state, and The pressure can always be controlled appropriately.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 2 shows a power train control system of an automobile incorporating an embodiment of the line pressure control device of the present invention, in which 1 is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, and 4 is a drive. It's a wheel.

The engine 1 includes an engine control computer 5,
This computer has the engine speed N.

A signal from the engine rotation sensor 6 that detects the vehicle speed, a signal from the vehicle speed sensor 7 that detects the vehicle speed, a signal from the throttle sensor 8 that detects the engine throttle opening TH, and an intake air amount that detects the engine intake air amount Q. sensor 9
Input the empty signal, etc.

The computer 5 determines the fuel injection pulse width T based on this information and instructs the engine 1 to do so, and also supplies the engine 1 with an ignition timing control signal (not shown). The engine 1 is supplied with fuel in an amount corresponding to the fuel injection pulse width T, and is operated by burning this fuel in time with the rotation of the engine.

The automatic transmission 2 also includes a torque converter 1o and a speed change gear mechanism 11 in tandem, and inputs engine power to an input shaft 12 via the torque converter 10.

The transmission input rotation to the shaft 12 is increased or decreased according to the selected gear position of the transmission gear mechanism 11, and reaches the output shaft 13. From this output shaft, the rotation is transmitted through the differential gear 3 to i[K! , fJ wheel 4 is reached and the car can be driven.

Here, the speed change gear mechanism 11 has an input shaft 12 and an output shaft 13.
It has built-in various friction elements (not shown) such as clutches and brakes that determine the transmission path (gear position) to the motor, and these various friction elements are selectively hydraulically actuated by line pressure P to select a predetermined gear position. At the same time, shifting to other gears is performed by changing the friction elements that are operated.

For this speed change control, a speed change control computer 14 and a control valve 15 are provided here.

The computer 14 selectively turns on shift solenoids 15a+15b for speed change control in the control valve 15.
Line pressure PL is selectively supplied to the various R friction elements so that the corresponding gear stage is selected by the combination of ON and OFF of these shift solenoids to control the shift. In addition, the shift control computer 14 duty-controls the line pressure control duty solenoid 16 in the control valve 15 using the drive duty D to maintain the line pressure PL in the control valve 15 (the line pressure increases as the duty D increases). It shall be controlled as intended by the invention. For the above-mentioned speed change control and line pressure control, the computer 14 receives a signal from the vehicle speed sensor 7 and a signal from the throttle sensor 8, respectively, and also inputs the rotation speed N7 of the shaft 12.
The signal from the input rotation sensor 17 that detects the rotation speed N of the shaft 13. A signal from an output rotation sensor 18 that detects the engine speed is inputted, and a signal I from an idle switch 19 that is linked to the throttle valve and turns ON when the engine throttle opening TH is near the fully closed position is also inputted.

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

First, the line pressure control program shown in FIG. 3, which is repeatedly executed by regular interrupts, will be explained. In step 30, it is checked whether or not the gear is being changed by checking whether a flag FLAG 1, which will be described later, is set to 1. As a result, during non-shifting (FLAG 1 =
If O'), then in step 31, the line pressure control solenoid drive duty D corresponding to the throttle opening TH is determined from the non-shift duty table 1 written in the RAM and having the characteristics as shown by the solid line A in FIG. 6, for example. is looked up in the table, and then in step 32 this drive duty D is output to the solenoid 16 to control the line pressure PL to a normal value for non-shifting.

On the other hand, as a result of the above check, the gear shift is in progress (FLAG 1 = 1
), in step 33, the gear, upshift,
This differs depending on the type of shift such as downshifting, and this is also RAM.
The line pressure control solenoid drive duty D corresponding to the throttle opening TH is looked up from the shift duty table 2 having characteristics as shown by the dotted line B in FIG. It is checked whether or not the shift is an upshift in which shift shock is particularly likely to occur due to excessive line pressure, and if the result is not an upshift, in this example device, the drive duty D is directly output to the solenoid 16 in step 32. do. On the other hand, in the case of an upshift, in step 35, 124
For example, the line pressure control solenoid drive duty correction amount ΔD corresponding to the throttle opening Tl+ is looked up from the correction amount table as shown in FIG.
to control the line pressure PL to a value for shifting.

Next, to explain the shift control and line pressure control solenoid drive duty correction amount control shown in FIG.
Check whether 1 is 1, that is, whether the gear is being shifted,
If not shifting (FLAG 1 = O), step 41
Then, a required gear position corresponding to the combination of vehicle speed (2) and throttle opening degree TH is determined based on a predetermined normal gear shift pattern.

In the next step 42, it is checked whether or not the gear should be changed based on whether the requested gear is different from the currently selected gear. If the result is that the gear should be shifted, then in step 43, a message is displayed to indicate that the gear is being shifted. In addition to setting FLAG 1 = 1, the solenoids 15a and 15b are turned ON and OFF to execute the shift to the above-mentioned required gear position, and in the following step 44, it is checked by the signal I whether the idle switch 19 is ON or not. , if the idle switch 19 is ON, in step 45, PLΔG3 is set to 1 to indicate that the engine state during gear shifting includes a power-off state, and then in step 4
Proceed to step 6 and turn on the idle switch in step 44.
Otherwise, the process proceeds to step 46 with FLAG 3 = O.

Note that during the gear shift (FLAG 1
= 1), steps 41 to 43 will be skipped in the next control, but steps 44 and 45 will be executed even during gear shifting. FLAG 3 = 1 even when the state changes to the power-off state.

In step 46, the timer T1 for measuring the shift time is incremented, and in the next step 47, it is checked whether or not the inertia phase is in progress.

In this check, the gear ratio represented by the input/output rotation speed ratio N/No of the transmission gear mechanism 11 is changed from the gear ratio corresponding to the gear before shifting to the gear ratio corresponding to the gear after shifting. The period during which is changing is determined to be in the inertia phase. And here, during the inertia phase, step 4
By incrementing the timer T2 at 8 and skipping 4 days after the inertia phase, the timer T2 measures the inertia phase time.

In the next step 49, it is checked whether or not the inertia phase has ended (the end of the shift). If it has not ended, the program is terminated as is, and if it has ended, the flag FLAG 1 is set to correspond to the end of the shift in step 50. Te 0
At the same time, the tlA? shown in FIG. A flag FLAG2 is set to 1 for executing learning control to correct the data in the correction amount table in l.

After the shift is finished in this way, the control proceeds to step 51 via steps 40 to 42, but since FLAG 2 = 1 as described above, step 52 is selected and the following steps are performed. Through learning control, the line pressure control solenoid drive duty correction amount Δ shown in Fig. 7 is
Correct and update the previous data of D.

In this step 52, the learning control subprogram shown in FIG. 5 is executed, and first in step 60, the FLAG
Check whether 3 = 1 or not, and set FLAG 3
If not equal to 1, the immediately preceding shift was a shift only in the power-on state, so the process proceeds to step 61, where it is checked whether the immediately preceding shift was an upshift shift. If it is not an upshift shift, the learning control is not performed as described above, and the process ends.If it is an upshift shift, on the other hand, in step 62, the timer T1, that is, the shift time is checked to see if it is greater than a predetermined value Tli. The measurement time of timers T+ and Tz for the line pressure control solenoid drive duty D+ΔD% during gear shifting is as shown by the solid line in Fig. 8 for the upshift shift in the power-on state. However, T1≧T
For example, when α is extremely small in the region showing I3,
Because the line pressure is extremely low, for example, the part where the selective pressure rises, the so-called shelf part, as shown in Figure 10, is too low overall, and at the end of the shelf part, the friction element suddenly increases due to the rapid increase in the selective pressure. Since the gears are fastened, the shift will be off-shelf as shown by the dotted line α in Figure 9, and the shift shock will be extremely large (
The solid line β and chain line γ in FIG. 9 are operating waveforms when the solenoid drive duty is at the value indicated by the circular symbol in FIG. 8, respectively. In order to prevent this off-shelf gear shift, if it is determined in step 62 that T, ≧Ls, in step 63, the throttle opening degree Tll at the time of gear shift is adjusted from the correction amount table mentioned above corresponding to the type of gear shift. The line pressure solenoid drive duty correction amount ΔD is looked up, and in the subsequent step 64, the correction amount ΔD is significantly increased by 2%, and in the subsequent step 65, the table data in the RAM is rewritten to the correction amount ΔD. Try to escape from the T1≧T+3jl area.

In the TI < TI 3 region, since there is no above concern, learning control of the correction amount ΔD is performed, and first step 66 is performed.
Then, set the target value T25 of the inertia phase time (different depending on the type of shift and throttle opening) that corresponds to the line pressure that is preferable for preventing shift shock and preventing reduction in the life of friction elements when shifting in the power-on state to the inertia in the RAM. While looking up from the phase time target value table, in step 67, the line pressure control solenoid drive duty correction amount Δ corresponding to the throttle opening TH is determined from the correction amount table described above corresponding to the type of shift.
D is looked up and the inertia phase time T2 is compared with the target value T2S in step 68.

Then, as a result of the comparison in step 68, T2 is 'hs
When they match, the table data in the RAM for the correction amount ΔD is not changed and is used as it is for line pressure control during the next shift. But ↑Z>T2! In this case, the line pressure is too low and the life of the friction element is shortened due to slipping. Therefore, by executing steps 69 and 70, the table data in the RAM of the correction amount ΔD corresponding to the type of shift is set to 0.
It is increased by 2% and used for line pressure control during the next gear shift. Therefore, during the next line pressure control, the line pressure control solenoid drive duty D + ΔD is increased by 0.2% from the previous time, and the line pressure can be increased by that amount, bringing the line pressure closer to the appropriate value and extending the life of the friction element. decline can be avoided. Conversely, when T2<T2S, the line pressure is too high and a large shift shock occurs due to the excessive engagement capacity of the friction element, so by executing steps 71 and 70, the RAM of the correction amount ΔD corresponding to the type of shift is stored. The table data within is reduced by 0.2% and used for line pressure control during the next shift. Therefore, the line pressure control solenoid drive duty D + ΔD during the next line pressure control is reduced by 0.2% from the previous time, making it possible to reduce the line pressure slightly, bring the line pressure closer to the appropriate value, and avoid large shift shocks. It can be prevented.

On the other hand, if FLAG 3 = 1 in step 60, the measured value of T2 is during gear shifting including the power-off state, and on the other hand, the inertia phase time target value T2S in this embodiment is as described above. It is suitable for shifting gears only when the power is on, as in
Moreover, for example, in power-off shift shifting at low vehicle speeds, the transient engagement capacity of the friction element is small, so even with the same throttle opening, the inertia phase time T2 is longer than in the case of only the power-on state, as shown in Figure 8. Therefore, in order to prevent erroneous learning, the table data of the correction amount ΔD is not corrected, and in step 72 the FLAG
After clearing 3 to O, this subprogram is ended and the process returns to step 52.

Thereafter, in step 53, FLAG 2 is reset to O, and the value of timer TI+r2 is reset to O to wait for the next measurement.

By repeating this action and learning side '4'BI), the line pressure solenoid drive duty correction ID adjusts the line pressure control solenoid drive duty D+ΔD during gear shifting to the line pressure, regardless of individual differences in automatic transmissions or changes over time. is the appropriate value (
The inertia phase time T2 is the target value T2. ), and the line pressure during gear shifting can be controlled to an appropriate value that will not shorten the life of the friction element or cause a large gear shift shock under any situation change.

Moreover, according to the device of this example, the inertia phase time target value suitable for shifting in the power-on state is used for learning control, and the learning control is not performed for the inertia phase time measured during shifting, including the power-off state. Therefore, it is possible to prevent erroneous learning due to differences in engine conditions during gear shifting, and to ensure that line pressure control during gear shifting is always appropriate.

Although the above has been explained based on the illustrated example, the present invention is not limited to the above-mentioned example. For example, learning control is performed not only for upshifting but also for downshifting, and it is possible to determine whether or not the learning control is possible. It may be determined.

(Effects of the Invention) Thus, according to the line pressure control device of the present invention, since learning control is performed only when the automatic transmission changes gears without including the power-off state, the measured value of the inertia phase time does not include the power-off state. It is possible to prevent erroneous learning due to the inclusion of the value in , and to ensure that line pressure control during gear shifting is always appropriate.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of the line pressure control device of the present invention, Fig. 2 is a control system diagram of an automobile power train showing an embodiment of the device of the present invention, and Figs. 3 to 5 are a computer for speed change control on the same side. 6 is a characteristic diagram of the line pressure control solenoid drive duty, and FIG. 7 is an instantaneous RA regarding the correction amount of the duty.
A diagram illustrating the data in M, FIG. 8 is a diagram showing the relationship between the timer measurement time and the line pressure control solenoid drive duty during gear shifting, and FIG. 9 is a diagram showing the solenoid drive duty indicated by α, β, and T in FIG. 8. Shift operation time chart when
FIG. 10 is a shift operation time chart showing the occurrence of an inertia phase during a shift. 1... Electronically controlled fuel injection engine 2... Automatic transmission 3... Differential gear 4... Drive wheels 5... Engine control computer 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 i5a, 15b... For speed change control Shift solenoid 1
6...Duty solenoid for line pressure control 17...
・Input rotation sensor 18...Output rotation sensor 19...Idle switch

Claims (1)

[Claims] 1. Selectively hydraulically actuate various friction elements of the transmission gear mechanism using line pressure to select a predetermined gear, and change the operating friction elements to shift to other gears. An input rotation sensor and an output rotation sensor respectively detect the input rotation speed and the output rotation speed of the speed change gear mechanism of the automatic transmission, and based on the signals from these sensors, the inertia phase time measuring means The line pressure adjuster measures the time during which the gear ratio represented by the ratio between the input and output rotational speeds is changing, and controls the line pressure during the shifting so that the inertia phase time reaches the target value. In the control device, a power-off signal output means for outputting a signal indicating whether or not the speed change for which the inertia phase time was measured is a speed change that includes a power-off state; 1. A line pressure control device for an automatic transmission, characterized in that the line pressure control device comprises a control enable/disable determining device for regulating line pressure control of the line pressure adjusting device during gear shifting based on the inertia phase time.