JPH05248530A - Speed change pressure controller of automatic transmission - Google Patents

Abstract

PURPOSE:To improve the effect of speed change shock reduction by controlling the pressure to operate a friction element at a torque phase separated from an inertia phase in the speed change by an automatic transmission. CONSTITUTION:When an automatic transmission performs up-shift speed change to a higher speed stage from a lower speed stage by engaging a certain friction element, a torque phase time measuring means measures the torque phase time to the moment when the speed change ratio begins to change at the beginning of speed changing. An optimum torque phase time calculating means determines optimum torque phase time favorable for reducing the shock caused by speed change according to the input to the automatic transmission. A speed change pressure learning controlling means performs learning control of the operation pressure of a certain friction element in the torque phase so that the actual torque phase time measured by the torque phase time measuring means may coincide with the optimum torque phase time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift pressure control device for controlling an operating pressure of a friction element that is engaged during a shift of an automatic transmission to a value suitable for reducing shift shock.

[0002]

2. Description of the Related Art In an automatic transmission, it is possible to select a corresponding shift speed by selectively hydraulically operating various friction elements (friction clutch, friction brake, etc.), and change gears to operate by changing the friction element to be operated. is there. Therefore, depending on the type of shift, it is necessary to change the friction elements that fasten a certain friction element and release the other friction element at the same time.

In particular, in the upshift shift from the low speed stage to the high speed stage by changing the friction elements, the shift operation waveform becomes as shown in FIG. 6, for example.
That is, after the response delay t ₁ from the instant of the speed change command from the low speed stage to the high speed stage, the friction element is switched over by the start of the engagement of a certain friction element to be engaged at the time of the shift, and the torque phase time t ₂ This changeover will be completed later (however, in the following description, for convenience of explanation of the present invention, the description will proceed with t ₁ + t ₂ as the torque phase time). After that, during the inertia phase time t ₃ as the engagement of the certain friction element progresses, the transmission input / output rotation ratio (effective gear ratio) changes from the gear ratio before gear shift to the gear ratio after gear shift, and the final finish phase FF. Press to end shifting.

As is clear from the waveform of the transmission output torque, the pull-in torque TQ1 in the torque phase TF is
Further, the peak torque TQ2 is generated in the inertia phase IF, and these greatly influence the shift shock. The start of the inertia phase can be regarded as the start of the inertia phase, for example, when the engine speed Ne starts to decrease and drops by 100 rpm from the peak value Nep, and the end of the inertia phase can be regarded as the transmission input / output rotation ratio after shifting. When the gear ratio is reached, it can be judged that the inertia phase has ended.

In controlling the operating pressure (shift pressure) of the certain friction element as a countermeasure against shift shock during the shift, the inertia phase time is conventionally set as described in, for example, US Pat. No. 4,653,350. By measuring t ₃ , the shift pressure during the shift period is corrected by the learning control so that the inertia phase time matches the target time suitable for reducing the shift shock. The aim is to keep the peak torque TQ2 during the inertia phase IF as small as possible within the range that does not prolong the gear shifting time or cause frictional element wear. Therefore, the shift shock is reduced.

[0006]

However, in such a conventional shift pressure control technique, as is apparent from the shift pressure change time chart of FIG. 6, the torque phase TF, the inertia phase IF, and the finish phase FF are basically different from each other. Whether the transmission pressure is different or different, the inertia phase time is monitored, and the transmission pressure correction amount ΔPu or ΔPd determined by the learning control is used as it is in other torque phase and finish phase. Therefore, the following problems occurred.

That is, in the inertia phase, the peak torque TQ2 involved in the shift shock depends on the transmission input torque, whereas in the torque phase, the torque pull-in TQ1 involved in the shift shock and its generation time t _{4 are} generated.
Is dependent on variations in hydraulic oil temperature (viscosity) and hydraulic oil path resistance of the automatic transmission. Even if the target subject to shift shock is different, it would be appropriate if the learning result of the inertia phase is used as it is in the torque phase to increase or decrease the shift pressure during the torque phase by the same value as the inertia phase. Not enough gear shift shock reduction effect.

An object of the present invention is to solve the above-mentioned problem by learning control by separating the shift pressure in the torque phase from the inertia phase.

[0009]

To this end, the present invention is, as shown in the concept of FIG. 1, an automatic transmission in which a certain friction element is engaged to perform an upshift from a low speed stage to a high speed stage. In the above, the torque phase time measuring means for measuring the torque phase time until the moment when the initial gear ratio of the upshift gearshift starts to change, and the preferable preferable torque phase time for reducing the shift shock according to the input to the automatic transmission are obtained. Shift pressure learning for learning control of the operating pressure of the certain friction element during the torque phase so that the actual torque phase time measured by the torque phase time calculating means and the torque phase time measuring means coincides with the preferable torque phase time. And a control means.

[0010]

The automatic transmission shifts from the low speed stage to the high speed stage by engaging a certain friction element. At the time of this shift, the torque phase time measuring means measures the torque phase time until the moment when the initial gear ratio of the upshift shift starts to change. On the other hand, the suitable torque phase time calculating means obtains a suitable suitable torque phase time for reducing the shift shock according to the input to the automatic transmission. Then, the shift pressure learning control means learns and controls the operating pressure of the certain friction element during the torque phase such that the actual torque phase time measured by the torque phase time measuring means matches the preferable torque phase time.

Therefore, during the torque phase, the shift pressure is determined so that the torque phase time becomes a preferable torque phase time preferable for reducing the shift shock, separated from the inertia phase, and the torque is pulled in and generated in the torque phase. The time is certainly favorable for the shift shock, and the shift shock reducing effect can be enhanced.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the shift pressure control device of the present invention, in which 1 is an engine, 2 is an automatic transmission, and the automatic transmission 2 makes the rotational power from the engine 1 rotate according to a selected shift speed. Transmit to the evil wheel.

The shift control of the automatic transmission 2 and the shift pressure control aimed at by the present invention are performed by the control valve 3. Therefore, the control valve 3 comprises shift solenoids 4 and 5 and shift pressure duty solenoid 6. The shift solenoids 4 and 5 can turn the automatic transmission 2 into any of the four forward gears by a combination of ON and OFF, and the duty solenoid 6 is a friction element that is activated during a gear shift. The operating pressure (shift pressure) is controlled according to the drive duty. In the case of an automatic transmission, all the friction elements are operated at a common line pressure. Therefore, the duty solenoid 6 may perform duty control on this line pressure. Good.

The solenoids 4 to 6 are the controller 7
ON / OFF control and duty control are performed by means of this, and for this reason, the controller 7 has a throttle opening TV
A signal from a throttle opening sensor 8 that detects O, a signal from an engine rotation sensor 9 that detects an engine speed Ne, a signal from an input rotation sensor 10 that detects an input speed Ni of the automatic transmission 2, an automatic speed change Machine oil temperature AT
A signal from an oil temperature sensor 11 that detects F, and a vehicle speed sensor 1 that detects the output speed (vehicle speed) VSP of the automatic transmission
Input the signals from 2 respectively.

The controller 7 performs gear shift control (not shown) based on these input information, and executes the control programs of FIGS. 3 and 4 to perform predetermined gear shift pressure control.

First, an outline of the shift control will be described. The controller 7 controls the throttle opening T detected by the sensors 8 and 12.
Based on VO and vehicle speed VSP, the optimum shift speed for the current driving state is determined based on a preset shift pattern, and when the currently selected shift speed is different from this optimum shift speed, the shift solenoids 4, 5 are turned on and off. The automatic transmission 2 is shifted to the optimum shift speed by switching to correspond to the optimum shift speed.

To explain the shift pressure control of FIG. 3, first, at step 21, it is checked whether or not the shift requiring the shift pressure control according to the present invention has started. As this shift, for example, there is an upshift shift by changing the friction elements, which is turned on and off of the shift solenoids 4 and 5.
Determine by switching. Until the upshift gear shift is started, a command is issued to the gear shift pressure duty solenoid 6 in step 22 to make the gear shift pressure a steady pressure according to the throttle opening TVO as usual.

When a shift requiring the shift pressure control according to the present invention is started, the torque phase timer TM (TF) for measuring the torque phase time is started in steps 23 and 24, and its operation is confirmed. Check whether or not after the torque phase TF is completed. In this determination, as described above with reference to FIG. 6, it is possible to determine that the torque phase ends when the engine speed Ne starts to decrease and decreases by 100 rpm. Until the end of the torque phase, that is, during the torque phase, a torque phase reference pressure Ptfo corresponding to the throttle opening TVO is determined by a table lookup method in step 26, and this torque phase reference pressure Ptfo will be described later in step 27. The operating pressure (shift pressure) to be supplied to the friction element in the torque phase is calculated by multiplying the torque phase pressure correction multiple n learned as described above, and the duty solenoid 6 is commanded.

When the torque phase ends, step 2
At 8, the timer TM (TF) is stopped and the actual torque phase time is measured. Next, in step 29, a table lookup is performed for the torque phase target time Ttfo according to the throttle opening TVO, and step 3
At 0, this torque phase target time Ttfo and timer T
The torque phase pressure correction multiple n is learned and controlled by comparing the measured time of M (TF) (actual torque phase time).

The details of steps 29 and 30 are as shown in FIG. 4. First, in steps 41 and 42, the allowable upper and lower limits Ttp and Tbm of the torque phase target time Ttfo corresponding to the throttle opening TVO are obtained. The allowable upper and lower limits Ttp and Tbm are the torque phase target time Tt.
for setting the dead zone of fo, step 43,
At 44, the torque phase time TM (TF) is within this dead zone, the torque phase time TM (TF) is longer than the torque phase target time upper limit value Ttp and beyond the dead zone, or the torque phase time TM (TF) is the torque. It is checked whether it is less than the phase lower limit value Tbm and is short of the dead zone.

If the torque phase time TM (TF) is longer than the dead zone and is longer than the torque phase target time upper limit value Ttp, the shift pressure in the torque phase is too low at the current value. Increase n by Δn to increase torque phase time TM (TF)
Is smaller than the torque phase lower limit value Tbm and is out of the dead zone, the shift pressure in the torque phase is too high at the present value, so the torque phase pressure correction multiple n is decreased by Δn in step 46. The torque phase pressure correction multiple n learned and controlled in this manner is used for the calculation of the torque phase pressure in step 27 of FIG. 3 as described above. As the multiple n increases, the operating pressure to be supplied to the friction element in the torque phase is increased. By increasing the torque phase time to the target time, the shift shock can be reduced.

Here, a supplementary explanation of the torque phase pressure correction multiple n and its correction amount Δn will be made. The initial value n _i of the torque phase pressure correction multiple is the operating oil temperature ATF of the automatic transmission.
Is set as a parameter as shown in FIG. The reason for increasing the multiple n at low temperature and high temperature is that the correction of the torque phase pressure must be increased in these temperature ranges to bring the torque phase time to the target value quickly. The torque phase pressure correction multiple correction amount Δn is also set as shown in the table shown in the figure with the hydraulic oil temperature ATF of the automatic transmission as a parameter, and the absolute value of + Δn when the torque phase time is too long and When the torque phase time is too short, the absolute value of -Δn is increased at high temperature and low temperature for the same reason as above. In the learning control of the torque phase pressure correction multiple n, n is corrected by n = n _i ± Δn the first time the engine is started, and thereafter, the previous value is added or subtracted by Δn to obtain the torque phase pressure correction multiple n.
Needless to say, learning control is performed.

In step 31 of FIG. 3, it is checked whether or not the inertia phase IF is completed. In this determination, as described above, the ratio of the transmission input / output speed detected by the sensors 10 and 12, that is, whether the effective gear ratio of the automatic transmission reaches the gear ratio corresponding to the gear after the gear shift or not. It is possible to determine whether or not the inertia phase IF has ended.

While the inertia phase is not yet completed, that is, during the inertia phase, steps 32 and 33 are performed.
In step 34, after the inertia phase timer TM (IF) for measuring the inertia phase time is started and its operation is confirmed, in step 34, the inertia phase reference pressure Pifo corresponding to the throttle opening TVO is obtained by the table lookup method, and the step is performed. At 35, the inertia phase reference pressure Pifo is set to the inertia phase pressure correction amount ΔPi set by the learning control described later.
Only f is added and corrected, and the duty solenoid 6 is commanded. This inertia phase pressure correction amount ΔPif has, of course, positive and negative polarities, and when it is negative, the friction element operating pressure in the inertia phase is lowered from the previous value.

When the inertia phase is completed and the finish phase FF is entered, in step 36, the timer T
The operation of M (IF) is stopped and the measurement of the actual inertia phase time is completed. Next, at step 37, the inertia phase target time T according to the throttle opening TVO
The ifo is looked up in the table, and in step 38, the inertia phase target time Tifo and the timer TM are set.
(IF) measurement time (actual inertia phase time)
And the inertia phase pressure correction amount ΔPif
And learning control of the finish phase pressure correction amount ΔPff described later. In this learning control, the actual inertia phase time TM (IF)
Is longer than the inertia phase target time Tifo, the shift pressure in the inertia phase and the finish phase is too low at the current value, so the inertia phase pressure correction amount ΔPif and the finish phase pressure correction amount ΔPff are increased by a predetermined amount, respectively. However, when the actual inertia phase time TM (IF) is shorter than the inertia phase target time Tifo, the shift pressure in the inertia phase and the finish phase is too high at the present value, so the inertia phase pressure correction amount ΔPif and the finish phase The pressure correction amount ΔPff is reduced by a predetermined amount.

The inertia phase pressure correction amount ΔPif learned and controlled in this way is used for the calculation of the inertia phase pressure Pif in step 35 as described above, and the working pressure to be supplied to the friction element in the inertia phase is calculated as the inertia phase time. Can be controlled so as to be brought to the target time to contribute to the mitigation of shift shock.

In the next step 39, the throttle opening T
The finish phase reference pressure Pffo corresponding to VO is obtained by a table lookup, and at step 40, the finish phase reference pressure Pffo is increased / decreased by the finish phase pressure correction amount ΔPff to obtain the finish phase pressure Pff.
Command. As a result, the operating pressure of the friction element is appropriately controlled due to the shift shock even in the finish phase.

By the way, in the above embodiment, the shift pressure Ptf during the torque phase is separated separately from the inertia phase so that the torque phase time TM (TF) converges within the range of the target time Ttp to Tbm. Since the correction is made by the pressure correction multiple n, the gear shift shock in the inertia phase depends on the transmission input torque, while the gear shift shock in the torque phase changes the hydraulic oil temperature ATF (viscosity) and the hydraulic oil passage resistance of the automatic transmission. Even if the object to which the shift shock depends depends on the variation, it is possible to adequately enhance the shift shock reduction effect by appropriately controlling the friction element operating pressure in the torque phase.

In the above example, t ₁ + t ₂ in FIG. 6 is measured as the torque phase time, and this is compared with the target time to learn and control the shift pressure (correction multiple n) during the torque phase. Since the delay t ₁ can be easily estimated from the automatic transmission operating oil temperature ATF, it goes without saying that only the time t ₂ may be measured and used for the learning control.

[0030]

As described above, the shift pressure control apparatus according to the present invention performs learning control so that the shift pressure in the torque phase is brought to the target torque phase time suitable for the shift shock. Because it was configured,
This learning control is executed separately from the inertia phase, and the shift pressure in the torque phase can be surely set to a pressure suitable for the shift shock, and the shift shock reducing effect can be greatly enhanced. ..

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a shift pressure control device of the present invention.

FIG. 2 is a system diagram showing an embodiment of a transmission pressure control device of the present invention.

FIG. 3 is a flowchart showing a shift pressure control program executed by the controller of the example.

FIG. 4 is a flowchart showing a subroutine of the same shift pressure control program.

5A and 5B are a diagram and a table showing an initial value and a correction amount of a torque phase pressure correction multiple used in the same example.

FIG. 6 is an operation time chart showing conventional shift pressure control.

[Explanation of symbols]

 1 Engine 2 Automatic Transmission 3 Control Valve 4 Shift Solenoid 5 Shift Solenoid 6 Duty Solenoid 7 Controller 8 Throttle Opening Sensor 9 Engine Rotation Sensor 10 Transmission Input Rotation Sensor 11 Oil Temperature Sensor 12 Vehicle Speed Sensor

Claims (1)

[Claims] 1. An automatic transmission in which a certain friction element is engaged to perform an upshift from a low speed stage to a high speed stage, and a torque phase time until the moment when the initial gear ratio of the upshift shift starts to change. Torque phase time measuring means for measuring, a preferable torque phase time calculating means for obtaining a preferable torque phase time preferable for reduction of shift shock according to an input to the automatic transmission, and an actual torque measured by the torque phase time measuring means. A shift pressure learning control means for learning and controlling the operating pressure of the certain friction element during the torque phase so that the phase time coincides with the preferable torque phase time. Control device.