JPS6299225A - Gear shift shock reducing device for automatic speed change gear - Google Patents

Abstract

PURPOSE:To aim at reducing the cost of a gear shift shock reducing device, by providing a discriminating means for evaluating the condition of gear shift operation and a means for regulating fluid pressure fed to a fluid pressure type friction element so that the output of an engine is controlled in accordance with the evaluation by the discriminating means and the operation of the regulating means. CONSTITUTION:A gear shift condition discriminating means 103 evaluates the condition of gear shift operation in accordance with the shape of waves indicating the torque of an output shaft during gear shift operation, which is obtained by a waveshape recognizing means 102. Then, fluid pressure regulating means 104 regulates fluid pressure fed into a fluid pressure type friction element 105 for gear shift operation, corresponding to the evaluation by the discriminations means 103. An engine output control means 106 controls the output of the engine as necessary so that gear shift shocks are reduced. With this arrangement, it is possible to obtain a sufficient effect of reduction of gear shift shocks without using a digital circuit having a high computing speed and a highly accurate torque sensor.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applicable to automatic transmissions for vehicles, and particularly relates to a shift shock reduction device for automatic transmissions that can reduce shift shock. Regarding.

(Prior Art) Conventional gear shift shock reduction devices for automatic transmissions include, for example, Japanese Patent Application Laid-Open No. 52-106064 and Japanese Patent Application Laid-open No. 53-85.
There is one described in No. 264.

The conventional device described above detects the output shaft torque of an automatic transmission with a torque sensor, and changes gears while feeding back a detection signal of the output shaft torque so that the output shaft torque changes in accordance with a preset torque change. By controlling the fluid pressure of the hydraulic friction element used in the transmission, the shift shock is attempted to be reduced.

(Problems to be Solved by the Invention) However, the conventional device described above detects the output shaft torque of the automatic transmission with a torque sensor, feeds back this ratio check signal, and detects the actual change in the output shaft torque. Since the configuration is such that real-time control is performed in accordance with preset torque changes, if this control is attempted to be performed using a digital calculation circuit such as a microcomputer, an expensive device capable of high-speed calculation will be required.

Furthermore, due to the real-time control described above, if error components such as noise are mixed into the torque sensor output, the control accuracy will immediately decrease.To prevent this, it is necessary to use a highly accurate torque sensor, that is, An expensive torque sensor is required.

Furthermore, if the engine output torque is excessive due to constraints such as the durability of the friction elements, it may not be possible to sufficiently reduce the shift shock simply by adjusting the supply pressure to the friction elements.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes means shown in FIG.

The waveform recognition means 102 recognizes the fluctuation waveform of the output shaft torque of the automatic transmission 100 detected by the output torque detection means 101.

The shift operation quality determination means 103 evaluates the quality of the shift operation based on the fluctuation waveform of the output shaft torque during the shift recognized by the waveform recognition means 102.

The fluid pressure adjustment means 104 includes the gear shift operation quality determination means 1
In response to the evaluation by No. 03, the fluid pressure supplied to the fluid pressure type friction element 105 for shifting that constitutes the automatic transmission is adjusted.

The engine output control means 106 controls the engine output as necessary based on the evaluation by the shift operation quality determining means 103 and the fluid pressure adjustment operation by the fluid pressure adjustment means 104.
7's output is controlled in a direction that reduces shift shock.

(Function) The present invention uses the waveform recognition means 102 and the speed change operation quality determination means 103 to evaluate the quality of the speed change operation based on the fluctuating waveform of the output shaft torque at the time of speed change. This method can be realized using a digital circuit that takes a slower calculation processing time than a method in which the detected value of the output shaft torque is fed back and compared with a preset torque change.

Further, the fluid pressure adjusting means 104 adjusts the fluid pressure of the fluid pressure type friction element 105 in response to the evaluation of the quality of the speed change operation by the speed change operation quality determining means 103. Even if error components such as noise are mixed in, by appropriately selecting the criteria for evaluating the quality of the gear shifting operation, evaluation can be made without being influenced by the error components mentioned above.For this reason, high-precision torque sensors It is no longer necessary to use a 2000 µm, and costs can be reduced.

Further, if the shift shock cannot be sufficiently reduced by adjusting the supply pressure to the friction element 105 alone due to constraints such as the durability of the friction element 105, the engine output control means 106 may be used to By controlling the engine output, the system assists the shift shock reduction operation by adjusting the supply pressure to the friction elements.

(Example) FIG. 2 shows the configuration of an embodiment of the present invention.

The control circuit 20 is mainly composed of a digital arithmetic circuit constructed using a microcomputer or other digital circuit. In the figure, some functions are shown in order to make the control functions easier to understand.

It is illustrated in the figure.

The information input to the control circuit 20 is the output shaft torque Tou of the automatic transmission (the path shown) detected by the torque sensor 10.
T, the throttle opening 5TH1 detected by the throttle opening sensor 11, and the rotation speed N0LI7 of the output shaft of the automatic transmission detected by the output shaft rotation speed sensor 12.

The torque sensor 10 is a well-known magnetostrictive torque sensor (similar to the one described in the above-mentioned conventional publication), and the output signal is an analog signal, so the control circuit 20
The signal is converted into a digital signal by an A/D converter 30 within the unit. The output signals of the throttle opening sensor 11 and the output shaft rotation speed sensor 12 are digital signals.

The output signal output from the control circuit 20 is a drive signal for a pressure control valve 40 that controls the fluid pressure of a hydraulic friction element for shifting that constitutes an auxiliary transmission mechanism of an automatic transmission, and an engine control signal that controls engine output. This is a correction signal for the control amount of the engine output, which is supplied to the device 41.

As shown in FIG. 3, the pressure control valve 40 is composed of a spool valve 51 and a solenoid valve 52.
The supply pressure PL (which is the output pressure from the oil pump) supplied to the input oil passage 55 is applied to the spool valve 51 as a control pressure P by a fixed orifice 53 and a variable orifice 54 whose opening degree is adjusted by a solenoid valve 52. As a result, the amount of displacement of the spool 51S is adjusted,
As a result, the output pressure P from the output oil passage 56 is adjusted. The output oil passage 56 is connected to the hydraulic oil supply passage of the hydraulic friction element.

The drive signal I given to the pressure control valve 40 from the control circuit 20 is the excitation current of the solenoid valve 52, and this drive signal I is the PW in the control circuit 20.
This is a pulse width modulated current signal output from the M circuit (pulse width modulation circuit) 31.

That is, by changing the ON/OFF duty ratio of the drive signal (2) using the PWM circuit 31, the amount of displacement of the spool 52S of the solenoid valve 52 is adjusted, and the opening degree of the variable orifice 54 is adjusted. As a result, the output pressure P is adjusted.

The engine control device 41 is a well-known electronic engine control device, and inputs various operating state parameters (for example, throttle opening, vehicle speed, engine speed, oxygen concentration in exhaust gas, etc.) (not shown), and This device adjusts the fuel ratio, ignition timing, exhaust gas recirculation amount, etc. to optimally control the engine.

Functionally, the configuration of the control circuit 20 can be divided into functional sections 21 to 28 as shown in FIG.

The shift point determination unit 21 determines the throttle opening degree 5T11 and the output shaft rotation speed N. The gear position of the automatic transmission is determined based on Ua.

When the gear position is determined by the shift point determining section 21, the pressure determining section 22 recognizes a change in the gear position, that is, when a shift is performed, and activates a hydraulic friction element for shifting at the time of the shift. A time change in the supply pressure is set in advance (this set time change in the supply pressure is referred to as a "reference pressure change").

The waveform recognition unit 23 detects the output shaft torque T. Enter u7,
Output shaft torque T during gear shifting. Recognize the fluctuating waveform of UT. Specifically, the output shaft torque T during gear shifting. U
Detect the peak value of T and its occurrence time.

Based on the peak value of the output shaft torque recognized by the waveform recognition unit 23 and the timing of its occurrence, the quality determining unit 24 determines whether the gear shifting operation causes discomfort to the driver when one gear shifting is performed. Are there any large torque changes that would cause
Alternatively, determine whether the shift time is so long that it causes wear on the friction elements.

The storage unit 25 is a memory, and determines the amount of correction of the supply pressure to the friction element or the amount of correction of the engine control amount according to the type of shift, the operating conditions, and the determination result of the acceptability determination unit 24. The arranged data is stored as a data table.

The pressure adjustment unit 26 determines the supply pressure change to the friction element to be applied during gear shifting based on the reference pressure change set by the pressure determination unit 22 and the correction amount of the supply pressure, and adjusts the PWM circuit 3
1 to generate an output for forming the drive signal r applied to the pressure control valve 40.

The correction necessity determining section 27 determines whether or not the control amount of the engine output needs to be corrected based on the determination by the quality determining section 24 .

The engine control amount correction section 28 outputs the correction amount provided from the storage section 25 to the engine control device 41 when the correction necessity determining section 27 determines that correction of the engine control amount is necessary.

Thereby, the engine control device 41 corrects the engine control amount determined based on the various operating state parameters described above using the correction amount, and controls the engine output according to the corrected control amount.

Next, FIGS. 4 to 6 show the control circuit 2o when the control circuit 2o is configured using a microcomputer.
2 is a flowchart illustrating processing executed at 0. Fourth
The processes shown in FIGS. 6 to 6 are a series of processes, and are repeatedly executed at predetermined time intervals.

In the process of step 61 in FIG. 4, the throttle opening ST
H and output shaft rotation speed N. Each input data of U is read.

In step 62, the contents of the control mode determination flag F are determined to determine which routine to proceed to thereafter. This flag F is set as 2-bit data, and when it is "00", it means "not shifting", and when it is "roll", it means "shifting".
, ``10j'' indicates that ``the quality of the gear shifting operation is being determined.'' Note that when the ignition switch is turned on, the flag F is reset to roOJ.

Assuming that the flag F=00 as a result of the determination in step 62, the operating conditions are then determined in the process of step 63, and the process of step 64 is based on the shift diagram previously stored in the memory. Then, it is determined whether the above operating conditions (throttle opening degree STH and output shaft rotational speed N, determined by IJ?) exceed a shift point that requires a shift.

Here, if the driving conditions are not such that shifting is required,
Exit the routine without any control. On the other hand, if a shift is required, steps 66 to 70 are performed.

In step 66, the fluid pressure to be applied to the fluid pressure type friction element for shifting during shifting is determined by lookup processing of a data table of pressure data (hereinafter referred to as "pressure data table") stored in the memory.

The above pressure data table shows the type of speed change (for example, “1
There are multiple cases depending on the operating conditions (throttle opening s'ro, output shaft rotation speed N.ur, vehicle speed, etc.). The required pressure data under each condition is stored.

In the next step 67, a data table of correction amount data (hereinafter referred to as "pressure correction amount table") stored in the memory is used.
The above step 66 is performed by the look amplification processing of
A correction amount ΔP (which is a one-time correction amount) is obtained for the pressure data obtained in , and the pressure data is corrected using this correction amount ΔP.

In the next step 68, the operating conditions for the current shift operation and the type of shift are determined by look-amp processing of a data table of engine output correction amount data (hereinafter referred to as "engine output correction amount table") stored in the memory. Find the engine output correction amount ΔE at the position determined by .

In step 69, the pressure data corrected in step 67 is output as a command value for the pressure to be supplied to the friction element (this will be referred to as "pressure command value P").

This pressure command value P is supplied to the PWM circuit 3I and converted into a drive signal I for the pressure control valve 40. This results in
The fluid pressure supplied to the friction element changes according to the pressure command value P.

By executing the above steps 66 to 69, the actual speed change operation is started. Therefore, in the next step 70, the flag F is set to "01" to indicate that "shifting" is in progress.

When the speed change operation is started as described above, the process of step 71 in FIG. 5 is performed, and it is determined whether or not correction of the engine output is necessary. This means that when E is read out to the engine output correction amount in step 68 above, this ΔE is "0".
This is a process of determining whether or not a correction amount other than `` is stored.

Here, if ΔF≠0, it is determined that engine output correction is necessary, and then, in step 72, the engine output correction amount ΔE is output to the engine control device 41.

Then, based on the result of determining the contents of the flag F in step 73, the process in step 74 is executed, and the A/D converter 30 is activated to calculate the output shaft torque T. L
12 data is read.

In the next step 75, the output shaft torque T during gear shifting is
. Find the maximum and minimum values of Ua. The obtained maximum value is temporarily stored as peak torque T.

The minimum value is also temporarily stored as the bottom torque T.

This process uses the output shaft torque T read in each routine process. This is done by comparing U with the maximum and minimum values obtained in the previous routine processing and updating it to a larger or smaller value.

In the next step 76, a process of measuring the shift time Jo (the time required from the start to the end of the shift operation) is performed. This process is performed at the start of gear shifting (when flag F is “
The value of the output shaft torque after the gear ratio has been changed is estimated from the output shaft torque after the gear ratio has been changed (when the output shaft torque becomes "Ol"), and if the value of the output shaft torque read in step 74 matches the estimated value or This process determines the shift time JH by assuming that the shift is completed when the shift time approaches a fixed value.

In step 77, it is determined whether or not the shift time J exceeds a preset allowable shift time J. This allowable shift time Jc is intended to limit the shift time in order to prevent excessively long shift time, which increases the degree of wear on the friction elements. This allowable shift time Jc varies depending on the operating conditions and the type of shift, so the appropriate allowable shift time J is determined by experiment or calculation by dividing into multiple cases in advance, and the results are stored in memory as a data table. Use what you have left.

When the shift time J exceeds the allowable shift time Jc (however, in this case, the end of the shift is not determined in step 76, and the shift time JH represents the elapsed time from the start of the shift), Through the process of step 78, a command value signal for generating a supply pressure to completely engage or completely disengage the friction element is output in place of the pressure command value P output in step 69. That is, in the case of complete engagement, the duty ratio of the drive signal I is set to 10 oz, so that the supply pressure to the friction element becomes the complete engagement pressure. Further, in the case of complete release, the duty ratio is set to 0%.

With this process, even before the conditions for determining that the shift is completed in step 76 are satisfied, the allowable shift time Jc
When this period has elapsed, the gear shifting operation is forcibly terminated to prevent wear of the friction elements.

In step 79, it is determined whether the conditions for determining that the shift has been completed in step 76 are satisfied. Here, if it is determined that the shift has ended, flag F=10 is set to indicate that the shift operation has ended (step 79).

Step 80 is a necessary process when the shift line γ is determined before the determination in step 77 becomes YES, and the same process as step 78 is performed.

When the speed change operation is completed and the flag F is set to "10", the processes of steps 82 to 92 shown in FIG. 6 are executed next.

In step 82, based on the peak torque T2 obtained in step 75, it is determined whether or not the shift operation performed this time was accompanied by a large torque fluctuation that caused a shift shock. Perform processing to evaluate. In other words, if the value of peak 1-lux T, - is less than a preset reference value for determining the occurrence of shift shock, it is determined that the shift operation has been performed satisfactorily.

Here, if it is determined that the shift operation has been performed satisfactorily, the determination in step 83 becomes YES, and in step 92, the flag F is reset to "00", and the control is terminated.

On the other hand, if it is determined in step 82 that the gear shifting operation was not performed satisfactorily, the determination in step 83 is NO.
After that, the processes of steps 84 to 91 are executed.

The processing in steps 84 to 91 is performed to calculate the peak torque T.

In order to adjust the supply pressure to the friction element according to the timing of occurrence, the engine This is a process of determining the engine output correction amount ΔE in order to control the output and assist in reducing the shift shock.

In step 84, it is determined whether the shift time Jll exceeds the allowable shift time Jc. Here, JH<Jc
If so, the peak torque T that caused the shift shock
, it is determined that this is due to the supply pressure to the friction element being too high, and in step 87, a new pressure correction amount ΔP is calculated.

The pressure correction amount ΔP calculated at this time is a value that generates a supply pressure lower than the supply pressure during the current shift, and the value is determined in accordance with the magnitude of the peak torque T2.

Figure 7 shows the supply pressure to the friction element and the output shaft torque 'rou
t, in which a drive signal I with a duty ratio corresponding to the pressure command value P is generated from a shift start time t0 to a shift end time t1, and a drive signal I with a duty ratio according to a pressure command value P is generated from a shift end time 1. This shows the state until the duty ratio becomes 100χ and the friction element is completely engaged.

As shown by the solid line a in Fig. 7 fbl, if the supply pressure is too high, the friction elements will engage rapidly, and the energy released when the engine speed changes with the change in gear ratio will be rapid. As a result, a large peak torque (indicated by the solid line A in fC1 in the figure) is generated after the start of the shift, resulting in a shift shift.

Therefore, in step 87, the pressure correction amount ΔP is determined so as to generate a supply pressure lower than the solid line a, as shown by the broken line in FIG.

The pressure correction amount ΔP determined in step 87 is determined in step 88 at a position in the pressure correction amount table used in step 67 that corresponds to the same conditions and type as the operating conditions and type of shift at the time of the current shift. The existing data will be replaced.

As a result, the next time a shift is performed under the same conditions and type as this time, the above-mentioned changed correction amount ΔP will be used in step 67, and the supply pressure will be lower than the current supply pressure. .

Therefore, as shown by the broken line B in FIG. 7(C), the released energy is sufficiently absorbed by the amount that the supply pressure is reduced, so the peak torque value is suppressed to a small value, and shift shock occurs. can be prevented.

Next, in step 84, if it is determined that 9≧j, it is determined whether the peak torque that caused the shift shock is due to a shelf shearing phenomenon. This is determined in step 85 at peak torque generation time 1.
．． The determination is made based on whether or not the shift has been completed.

The above-mentioned shelf shearing phenomenon is caused by the supply pressure being too low at the time t when the shift starts, as shown by the dashed line C in Fig. 7 fbl.
. Since the engagement of the friction elements has not progressed sufficiently between the time t1 and the time t1 when the shift ends, the energy emitted by the engine that should be absorbed during the shift period cannot be fully absorbed, and at the end of the shift, the friction elements are not fully engaged. When fastening is performed, the unabsorbed residual energy is suddenly released, resulting in a large torque fluctuation (as shown by the dashed line C in FIG. 7 (C1)).

If it is determined in step 85 that the peak torque exceeding the reference value is due to the shelf shearing phenomenon, then in step 89, when the previous gear change under the same conditions and type was performed,
It is determined whether a correction to increase the supply pressure has been made.

Here, if the supply pressure was not increased in the previous process, in the process of step 87, the supply pressure is made higher than the current supply pressure during the next shift to prevent the shelf slipping phenomenon. Calculate the pressure correction amount ΔP.

On the other hand, if it is determined in step 89 that the supply pressure has already been increased in the previous process, it is determined that the shelf shearing phenomenon cannot be prevented even if the supply pressure is increased further. , step 90 calculates the engine output correction amount ΔE.

This engine output correction amount ΔE is obtained by determining how much the engine output should be reduced in order to suppress the value of the peak torque T caused by the shelving phenomenon to a reference value or less.

The engine output correction ■ΔE obtained in step 90 is
In step 91, it is updated and stored in the engine output correction amount table used in step 68 at a position corresponding to the same conditions and type as the operating conditions and type of gear change at the time of the current gear change.

As a result, the next time a gear shift is performed under the same conditions and type as this time, the engine output correction amount ΔE after the above change is read out in step 68, and the engine output is controlled while adjusting the supply pressure. will also be held.

Therefore, if adjusting the supply pressure alone is not sufficient to prevent the shelf shearing phenomenon, the engine output may also be controlled to assist in reducing the shift shock caused by adjusting the supply pressure. There is.

Next, in step 85, if it is determined that the peak torque T, which caused the shift shock, is not due to the shelf shearing phenomenon, then step 85 is performed.

At block 86, the same processing as step 89 is performed.

This indicates that when the supply pressure was not increased in the previous process, a large peak torque occurred before the end of the shift, even though the shift time J was long. This is because it is determined that the supply pressure is still too high even though it was reduced in the previous process, and in the process of step 87, a pressure correction amount ΔP for further lowering the supply pressure is calculated.

On the other hand, if it is determined in step 86 that the supply pressure was increased in the previous process, this indicates that the supply pressure was increased because a shelf shearing phenomenon occurred during the previous gear shift. , Even though the supply pressure was increased last time, a shift shock occurred during the current shift.1 This is a situation in which the shift shock cannot be sufficiently alleviated by adjusting the supply pressure alone. It is thought that there is.

Therefore, in this case as well, when the process of step 90 is performed and the next shift operation under the same conditions and type is performed,
In conjunction with the adjustment of the supply pressure, an engine output correction amount ΔE is determined so as to reduce the engine output.

As described above, in this embodiment, each time a gear shifting operation is performed,
Based on the magnitude of the peak torque and the timing of its occurrence, the quality of the gear shifting operation is determined, and based on this determination, the pressure correction amount ΔP for reducing the gear shifting shock is determined, and the supply pressure is adjusted to an appropriate value. At the same time, if adjusting the supply pressure alone cannot sufficiently reduce the sudden shift shock, a sufficient effect of reducing the shift shock can be obtained by supplementarily controlling the engine output.

(Effects of the Invention) As explained in detail above, the present invention recognizes the fluctuating waveform of the output shaft torque during gear shifting of an automatic transmission and evaluates the quality of the gear shifting operation. Compared to systems such as those that feed-hack the detected value of the output shaft torque in real time and compare it with preset torque changes, it can be realized using a digital circuit that has a slower calculation processing time and can reduce costs. can.

In addition, by adjusting the fluid pressure of the fluid pressure friction element in response to the above evaluation of the quality of the gear shifting operation, error components such as noise are mixed into the detection signal of the torque sensor that detects the output shaft torque. Even 1. Evaluation of quality of gear shifting operation 5q
If = is appropriately selected, evaluation can be performed without being influenced by the above error component, and therefore there is no need to use a highly accurate torque sensor, and costs can be further reduced.

Furthermore, if the shift shock cannot be sufficiently reduced by adjusting the supply pressure to the friction element alone due to constraints such as the durability of the friction element, engine output may be controlled as necessary. By adjusting the supply pressure to the friction element, the shift shock reduction operation is assisted, and the shift shock reduction effect can be more reliably obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a sectional view showing the specific configuration of the pressure control valve in FIG. 2, and FIG. 6 to 6 are flowcharts showing the processing executed by the control circuit in FIG. 2, and FIG. 7 shows the relationship between the drive signal, the supply pressure to the friction element, and the output shaft torque in the same embodiment. FIG. DESCRIPTION OF SYMBOLS 100... Automatic transmission 101... Output torque detection means 102... Waveform recognition means 103... Transmission operation quality determination means 104... Fluid pressure adjustment means 105... Fluid pressure type friction element 106... - Engine output control means 107... Engine 10... Torque sensor 11... Throttle opening sensor 12... Output shaft rotation speed sensor 20... Control circuit 40... Pressure control valve 4
1...Engine control device T. Ua...Output shaft torque T,...Peak torque J□...Shift time Jc
...Allowable shift time ΔP...Pressure correction amount ΔE...
・Engine output correction amount patent applicant: Nissan Motor Co., Ltd. Representative Patent Attorney: Hidetoshi Sugimura Patent Attorney: Oki Sugimura Figure 1 Figure 3 Evening

Claims (1)

[Claims] 1. Output torque detection means for detecting output shaft torque of an automatic transmission; Waveform recognition means for recognizing a fluctuation waveform of the detected output shaft torque; and Waveform recognition means for recognizing a fluctuation waveform of the detected output shaft torque. A shift operation quality determining means for evaluating the quality of the gear shifting operation based on a fluctuating waveform of output shaft torque during gear shifting; Based on the evaluation by the fluid pressure adjustment means for adjusting the fluid pressure supplied to the pressure type friction element and the shift operation quality determination means and the fluid pressure adjustment operation by the fluid pressure adjustment means, the engine output is adjusted as necessary. 1. A shift shock reducing device for an automatic transmission, comprising engine output control means for controlling gear shift shock in a direction that reduces the shift shock.