JP2002079854A - Shift control device of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a suitable down shift even in any mode. SOLUTION: Torque recovery after reduction control of engine output torque Tc is performed by sweeping away in each case; in time t2C longer than reference time in a down shift while up shifting; in time t2A shorter than the reference time in a down shift followed by the next down shift immediately thereafter and the reference time in an ordinary down shift of none of these. Thus, peak torque is prevented in the down shift while up shifting, and output shaft torque quickly rises in the down shift followed by the next down shift immediately after the shift, so that an accelerating feeling is not impaired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for a motor vehicle equipped with an engine and an automatic transmission, and relates to a shift control method such as a downshift during an upshift and a downshift immediately before the next downshift. The present invention relates to a method for controlling engine output torque in shift control so that a suitable downshift is realized even in a downshift in such a mode.

[0002]

2. Description of the Related Art A control device for adjusting an engine output torque in a downshift is disclosed, for example, in Japanese Patent Publication No. 7-599.
No. 04 proposes this. In this example, when the turbine (transmission input shaft) rotation speed reaches a reference rotation speed set by a predetermined amount lower than the expected convergence rotation speed (rotation speed after shifting), this is detected, and fuel injection is started from the time point. The engine output torque is reduced by correcting the amount in the decreasing direction. This torque reduction suppresses the peak torque during shifting and reduces shift shock.

[0003]

However, downshifting includes downshifting in various modes, such as a downshift during an upshift (off-up) and a downshift immediately before the next downshift. There is a shift. In the case of a downshift during an upshift, the downshift is performed from a state in which the torque is smaller than that of a normal downshift, so that the difference in torque between before and after the return of the above-described torque reduction control becomes considerably larger than usual. As a result, a sudden torque return causes an increase in end shock.
Conversely, when a downshift is performed immediately before the next downshift is performed, if a long time is required for the torque recovery, the output shaft torque does not readily increase and the feeling of acceleration is impaired.

Therefore, the present invention is suitable for downshifting in any mode, such as downshifting during an upshift or downshifting immediately before the next downshift, without causing the above-mentioned inconvenience. It is an object of the present invention to provide a shift control device for an automobile in which a downshift is realized.

[0005]

The present invention according to claim 1 (see, for example, FIGS. 1, 10 and 11) provides an engine and an input rotation from the engine output by disconnecting a plurality of friction engagement elements. An automatic transmission that changes the transmission path by contacting and changes the transmission path and outputs the shifted rotation to the axle;
A shift control device for an automobile, wherein the automatic transmission is downshifted. An engine control means (1c) for reducing and controlling an output torque (T _c ) from the engine during the downshift, A mode determining means (1d) for determining the state of the downshift in a series of shift operations, and the engine control means (1) based on the determination of the mode determining means (1d).
c) a return control means (1f) for changing the return (t ₂ ) from the reduction control.

According to a second aspect of the present invention (for example, see FIGS. 9, 11 and 13), the mode determining means (1d) comprises:
A first mode that is a single downshift and a second mode that is a downshift during an upshift;
The return control means (1f) sets the mode change means as the return sweep time (t ₂ ) as the return to be changed.
When d) determines the first mode, the reference time (t _2B )
2. The shift control device for an automobile according to claim 1, wherein when the second mode is determined, a time (t _2C ) longer than the reference time (t _2B ) is adopted.

According to a third aspect of the present invention (see, for example, FIGS. 9, 11 and 12), the mode determining means (1d) comprises:
A first mode that is a single downshift; and a third mode that is a downshift immediately before the next downshift. The return control unit (1f) performs the return to be changed. Is the return sweep time (t ₂ ), the reference time (t _2B ) is adopted when the mode determining means (1d) determines the first mode, and the reference time (t _2B ) is used when the third mode is determined. 3. The shift control device for a motor vehicle according to claim 1, wherein the time (t _2A ) is shorter than the time (t _2B ).

The present invention according to claim 4 (see, for example, FIGS. 1, 8, and 10) provides an extra amount of torque supplied from the engine to the automatic transmission with respect to a target value (N _TA ). A torque difference detecting means (1b) for detecting and calculating the shortage amount, wherein the engine control means, when the torque calculated based on the torque difference detecting means (1b) is excessive, sets a reference value (T _CA ), the reduction control is performed so as to reduce the extra torque, and when the calculated torque is insufficient, to add the insufficient torque to the reference value (T _CA ). A shift control device for a motor vehicle according to any one of claims 1 to 3.

[Operation] Based on the above configuration, the return such as the return sweep time (t ₂ ) is appropriately changed according to the state of the downshift during operation in a series of shift operations. To return from the reduction control.

For example, the downshift currently in operation is a first mode in which the downshift is performed alone, a second mode in which the downshift is performed during an upshift, and the downshift immediately before the next downshift is performed. It is determined which mode, such as the third mode that is the shift, and the return sweep time (t ₂ ) of the output torque (T _c ) after the reduction control is determined according to the determination result. Is done.

The reference numerals in parentheses are for the purpose of comparison with the drawings, but are for the purpose of facilitating understanding and speeding up the understanding, and have no influence on the structure of the claims. It does not give.

[0012]

According to the first aspect of the present invention, the return from the appropriate reduction control is performed in accordance with the state of the downshift during operation in a series of shift operations. Even in such a mode of downshifting, downshifting with a suitable feeling becomes possible.

According to the second aspect of the present invention, in the case of a downshift during an upshift, the torque is gently restored by taking a return sweep time longer than the reference time, so that end shock is prevented.

According to the third aspect of the present invention, when a downshift is performed immediately before the next downshift is performed, the torque is restored in a return sweep time shorter than the reference time. It can be raised quickly and the feeling of acceleration is not impaired.

According to the fourth aspect of the present invention, in a situation where excess energy is supplied from the engine during the downshift and engine blowing occurs, the torque corresponding to the excess energy is reduced to the engine output torque reference value. Therefore, the shift torque can be reduced by suppressing the peak of the output torque due to the engine blowing, and in a situation where the energy from the engine is insufficient due to tie-up or the like, the torque corresponding to the insufficient energy is supplied to the engine. Since the output torque is added to the output torque reference value, it is possible to suppress a drop in output torque due to tie-up or the like, reduce a pull-in feeling (braking action feeling), and improve a shift feeling.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present automatic transmission has a number of frictional engagement elements such as clutches or brakes, and an automatic transmission in which the transmission path of a planetary gear is selected by appropriately connecting and disconnecting these frictional engagement elements. A mechanism (not shown) is provided, and the input shaft of the automatic transmission mechanism is connected to an engine output shaft via a torque converter, and the output shaft is connected to drive wheels. More specifically, the present automatic transmission is applied to one having five forward speeds and one reverse speed disclosed in Japanese Patent Application Laid-Open No. 9-21448.

FIG. 1 is a block diagram showing an electric control system. Reference numeral 1 denotes a control unit (ECU) comprising a microcomputer (microcomputer), an engine rotation sensor 2 and an accelerator pedal for detecting an accelerator pedal depression amount of a driver. Opening sensor 3, sensor 4 for detecting the actual throttle opening in the engine, transmission (automatic transmission mechanism)
The signals from a sensor 5 for detecting an input shaft rotation speed (= turbine rotation speed), a vehicle speed (= automatic transmission output shaft rotation speed) sensor 6 and an oil temperature sensor 7 are input. The signals are output to an electronic throttle system (engine operating means) 8 to be controlled and linear solenoid valves (pressure adjusting means) SLS and SLU of a hydraulic circuit. The control unit 1 controls the linear solenoid valve SLS or S
A hydraulic control unit 1a for transmitting a pressure regulation signal to the LU and an engine control unit 1c for transmitting a throttle opening command to the electronic throttle system 8 are provided.

Further, the control unit 1 detects and calculates the energy input to the automatic transmission (running system), and determines that the energy supplied from the engine to the automatic transmission such that engine blowing occurs is larger than a target value. In the case of, the engine output torque is corrected in the direction of decreasing the torque corresponding to the calculated energy, and the energy supplied to the automatic transmission from the engine becomes insufficient than the target value due to tie-up or the like. In this case, there is provided a torque difference detecting means 1b for outputting a signal for correcting the engine output torque in a direction to add a torque corresponding to the calculated energy.

The control unit 1 also receives inputs from each sensor,
Shift determining means 1e for determining a shift process to be performed, such as an upshift or a downshift, based on a map (not shown).
have. Further, the control unit 1 controls the shift determining unit 1e.
Based on the determination result (stored as the value of the flag)
The downshift currently being performed includes a single downshift (first mode), a downshift during upshifting (second mode), and a downshift immediately before the next downshift (third mode). Mode) to determine which mode is the mode.

The control unit 1 is provided with the mode determining means 1d.
Based on the determination of, and a return control means 1f for changing the return sweep time t ₂ from the reduction control by the engine control unit 1c. Specifically, the return control means 1
f is the return sweep time t ₂ and the mode determination means 1
When d determines the first mode, the reference time t _2B is employed. When the second mode is determined, the time t _2C longer than the reference time t _2B is employed, and the third mode is determined. In this case, a time t _2A shorter than the reference time t _2B is adopted (see FIG. 11). Detailed operations of the mode determining means 1d and the return control means 1f will be described later.

FIG. 2 is a diagram schematically showing a hydraulic circuit.
It has two linear solenoid valves SLS and SLU constituting the hydraulic control means 1a, and switches the transmission path of the planetary gear unit of the automatic transmission mechanism to achieve, for example, a forward fourth speed or a fifth speed and a reverse first speed. A plurality of hydraulic servos 9 and 10 for connecting and disconnecting a plurality of frictional engagement elements (clutches and brakes). The input ports a ₁ and a ₂ of the linear solenoid valves SLS and SLU are supplied with a solenoid modulator pressure, and the output ports b of these linear solenoid valves are provided.
The control oil pressures from ₁ and b ₂ are supplied to the control oil chambers 11a and 12a of the pressure control valves 11 and 12, respectively. Pressure control valves 11, 12
The line pressure is supplied to the input ports 11b and 12b, respectively, and the pressure regulation from the output ports 11c and 12c regulated by the control hydraulic pressure is applied to the shift valve 1 respectively.
The hydraulic servos 9 and 10 are supplied to the hydraulic servos 9 and 10 via the switches 3 and 15 as appropriate.

This hydraulic circuit is for showing the basic concept, and the hydraulic servos 9 and 10 and the shift valves 13 and 15 are shown symbolically.
A number of hydraulic servos are provided corresponding to the automatic transmission mechanism, and a number of shift valves for switching the hydraulic pressure to these hydraulic servos are also provided.

Next, the power-on downshift will be described with reference to FIG. 3. First, the control of the release hydraulic pressure PA will be described with reference to FIGS. Note that, specifically, a downshift (kickdown) in which the driver steps on the accelerator pedal to request a torque,
2 shows a state in which two shifts are performed.
The hydraulic pressure PA of the hydraulic servo of the C3 clutch is
(Exclusively for pressure regulation) Pressure regulation is controlled by the linear solenoid valve SLS. The hydraulic pressure here is not the hydraulic pressure supplied to the actual hydraulic servo, but the hydraulic control means 1 of the control unit 1.
5A shows an electric signal sent from a to the linear solenoid valves SLS and SLU, or a control oil pressure from the output ports b ₁ and b ₂ of the linear solenoid valve based on the electric signal.

Throttle opening sensor 3 and vehicle speed sensor 6
When the control unit 1 determines a downshift based on the signal from the map, the timing is started and the shift control is started after a predetermined delay time from the shift determination (S1). At the start time point (t = 0), the release hydraulic pressure PA is at the engagement pressure, and the release friction engagement element is engaged. The disengagement side torque T _A is calculated by the function of the input torque Tt (S2). The input torque Tt is obtained by calculating an engine torque based on a throttle opening and an engine speed using a map, further calculating a speed ratio from an input / output speed of the torque converter, obtaining a torque ratio from the map based on the speed ratio, It is determined by multiplying the torque by the torque ratio. Further, the release-side torque T _A is obtained by involving the torque sharing ratio and the like in the input torque.

The waiting engagement pressure Pw release side from the release side torque T _A is calculated (S3), and outputs a control signal to the linear solenoid valve as disengagement side pressure PA is該待machine engagement pressure Pw ( S4), the control of the release hydraulic pressure based on the input torque and the like is continued until a predetermined time tw has elapsed (S4).
5). The standby control is performed in steps S2 to S4, and the standby control time tw is changed by the input torque Tt.

Then, the predetermined release-side hydraulic pressure P _AS and the release-side torque T _A are calculated in the same manner as described above (S7, S8), and the target hydraulic pressure P _TA is calculated based on the release torque T _A (S9). Further, the margin ratio (degree of tie-up) S ₁₁ , S ₂₁
Thus, the release-side target oil pressure _PTA is calculated in consideration of the drive feeling (S10). Note that the above margin rate is
It is obtained from a large number of throttle opening / vehicle speed maps selected according to differences in oil temperature, and is generally S ₁₁ > 1.
0, S ₂₁ > 0.0.

Furthermore, the preset time t _TA, the gradient to the target hydraulic pressure _{P TA, [(P AS -P} TA) /
t _TA ], and the sweep down is performed by the gradient (S11). That is, in the power-on state, the sweep-down having a relatively steep gradient is performed, and continues until the release hydraulic pressure PA reaches the target hydraulic pressure _PTA immediately before the start of the inertia phase (S12). Then, the release-side hydraulic pressure change [delta] P _TA is a function _{[δP TA = fδ PTA (ωa} )]
(S13). Note that ωa is a target target input shaft rotation change rate (target rotation acceleration) at the start of rotation change of the input shaft rotation speed (gear ratio) N with respect to the output shaft rotation speed. Then, a gradient by the hydraulic change [delta] P _TA is a (second) sweep-down is performed (S1
4), the sweep-down is, in the power-on state, the input shaft rotational speed N _TS before the shift start, the rotational variation amount ΔN with a predetermined accuracy is continued until the shift start judgment rotation speed detected (S15 ). Steps S7 to S14 are the initial shift control, in which the torque capacity of the disengagement-side friction engagement element is reduced, but the shift is not progressing.

Next, the sweep-down is performed at a gradient based on a predetermined hydraulic pressure change δP _I having a relatively low gradient set in advance (S16). In the sweep-down, when the release hydraulic pressure PA is larger than the load pressure of the return spring of the hydraulic servo in the power-on state, that is, when the torque capacity of the release hydraulic servo does not become 0, the gear shift starts (rotation change starts). AF of change in total number of revolutions from shift to completion of gear shifting
[%], That is, up to a predetermined shift progress (S1
8). The above-mentioned shift progress rate is determined based on the input shaft rotation speed at the start of the rotation change, N _TS , and the amount of change in the input shaft rotation speed based on the gear ratio from the start of the rotation change to the present (to the output shaft rotation speed due to constant rotation). Assuming that ΔN, the gear ratio before shifting is g _i , and the gear ratio after shifting is g _{i + 1} ,
[(ΔN × 100) / (N _TS / g _i ) · (g _{i + 1} −
g _i )]. The sweep down at the gradient δP ₁ becomes the inertia phase control, and the change of the input shaft rotation speed _NT based on the gear ratio is started.

Then, the input shaft rotation speed N_TChanges are stable
A predetermined shift progress degree aF [%], for example, 20 [%] has elapsed.
Then, the downshift feedback control (S20)
Done. The feedback control is based on the actual input shaft
(Turbine) Rotational speed change rate (acceleration) and target input
So that the difference from the change rate of the force axis rotation speed is minimized
Is controlled in the shift progress stage. At this time, the torque converter
Is set at each stage of the above control based on the speed ratio of
May be corrected.
No. 145942). The feedback control includes
The change in gear ratio at which the degree of progress completes the downshift
A2 [%] near the rotation speed, for example, 90 [%].
(S21). In addition, the control of the engagement side hydraulic pressure described later and
Servo control time t_SEUntil the end of (S2
3) The engagement side oil pressure PB is equal to the target oil pressure P _TBBigger
(S24) until the feedback control (S2
0) is continued. In step S20, the feedback
Control.

When the shift up to a2 [%] is completed, a predetermined oil pressure change δP _FA having a relatively steep gradient is set, and the sweep down is performed at the gradient (S25).
When the release hydraulic pressure PA becomes 0, the release hydraulic control at the time of the downshift is completed (S26). Step S above
25 is the completion control.

Next, the control of the engagement side hydraulic pressure PB in the downshift will be described with reference to the flowcharts of FIGS. 6 and 7 and the time chart of FIG. Note that, specifically, as described above, the 4-2 downshift is performed, so the engagement-side friction engagement element is a B5 brake, and the hydraulic pressure PB of the hydraulic servo is linear (for lock-up control). The pressure is controlled by the solenoid valve SLU.

First, timing is started based on a downshift command from the control unit 1 (S30), and a predetermined signal is output to the linear solenoid valve SLU so that the engagement side hydraulic pressure PB becomes the predetermined pressure P _S1 (S31). . The predetermined pressure P _S1 is set to a hydraulic pressure required to fill the hydraulic chamber 20 of the hydraulic servo, and is maintained for a predetermined time t _SA . When the predetermined time t _SA has elapsed (S32), the engagement side hydraulic pressure PB sweeps down at a predetermined gradient [(P _S1 −P _S2 ) / t _SB ] (S3).
3) When the engagement side hydraulic pressure PB becomes the predetermined low pressure P _S2 (S3
4), the sweep-down is stopped and the predetermined low pressure _PS2 is maintained (S35). The predetermined low pressure P _S2 is set to a pressure that is equal to or higher than the piston stroke pressure and does not cause a change in the rotation of the input shaft, and the predetermined low pressure P _S2 is maintained until the time t reaches a predetermined time t _SE (S36). ). Steps S31 to S36 correspond to the servo start control.

[0033] Then, the engaging torque T _B is disengagement side pressure P
A and the function of the input torque Tt [T _B = f _TB (PA, T
is calculated by t)] (S37), and further consideration of the margin, the engaging torque T _{B is, [T B = S 1D ×} T B + S
_2D ] (S38). Then, the engagement side pressure PB is calculated from the engagement side torque T _B [PB = f
_PB (T _B )] (S39). Steps S37 to S39 above
Is the engagement control. Then, control of the engagement hydraulic pressure PB based on the engagement side input torque T _B (depending on the disengagement side pressure PA and the input torque Tt) by the step S39 is, a1 [%] of the total shift progress degree of downshifting, For example, it continues up to 70 [%] (S40). That is, the input shaft rotational speed of the shift start time and N _TS, the rotational variation amount of .DELTA.N, pre-shift to g _i gear ratio, when the g i _{+ 1} and after shifting gear ratio, [(ΔN × 10
0) / (N _TS / g _i ) · (g _{i + 1} −g _i )] is a1
Continue until [%] is reached.

In step S40, if the total shift progress degree exceeds a1 [%], the end control is started. First, the engagement-side target pressure P _TB is calculated from the engagement side input torque T _B (S4
1) Further, the engagement side hydraulic pressure PB at the time of the rotation change amount a1 [%] is stored as P _LSB (S42). As a result, a predetermined gradient [(P _TB −P _LSB ) / t _LE ] is calculated based on a predetermined time t _LE that is set in advance, and the sweep-up is performed with the relatively gentle gradient (S43). This is continued until the engagement side oil pressure reaches the target oil pressure P _TB (S44). Further, a predetermined gradient δP _LB is set, and the sweep is performed at the gradient (S46). In the sweep-up, the shift progress degree is a2 [%], for example, 90%.
Continue to [%] (S47). The above-described steps S41 to S46 are the final control.

Further, an end time t _F of the end control is set (S48), a relatively steep gradient δP _FB is set, and the slope is swept up (S49).
The completion control time t _{FE is} continued (S50). The gradient δP _FB
When the power is on, the sweep-up of step S2
5 is set steeply in accordance with the release side hydraulic pressure δP _FA . Steps S48 and S49 are the completion control.

Next, the engine torque control will be described with reference to FIGS. 8, 9 and 10. FIG. As described above, the input rotation speed _NT is increased by the feedback control (S20) of the release hydraulic pressure PA, and when the control of the input rotation speed is started (N
_TS ), the variation ΔN from the predetermined value a1 is set in advance.
When it reaches [%], for example, 70 [%] (see S40),
That is, when the progress of the shift mainly by the release-side hydraulic pressure PA approaches the end, and the engagement-side hydraulic pressure PB is in a state near the transition from the engagement control to the end control, the torque reduction control of the engine is activated (S50). If the torque-down timing is always constant, if the number of rotations at the start of shifting is large, that is, if the amount of change in rotation during shifting is large, the amount of heat generated by the disengagement-side friction engagement element also increases. Is delayed, the durability of the friction material may be impaired. However, in the engine torque control, as described above, the start point of the torque reduction is determined by the input rotation speed N _TS at the start of the shift control.
Since it is set based on (ΔN = 0) (ΔN ≧ a1),
From the high vehicle speed to the low vehicle speed, it is possible to prevent the durability of the disengagement side frictional engagement element from lowering.

[0037] Then, the predetermined value a1 to calculate a change rate i.e. acceleration dN ₁ input rotational speed in [%], based on said change ratio, for example, by a predetermined relationship such as direct proportion function calculates a torque reduction amount T _ca ( S51). Further, after the control amount _Tc of the engine torque at this time is virtually and set to 0 (S52), the control amount is controlled. The control amount _Tc of the engine torque is calculated as a correction amount by calculating an extra energy supplied by the engine blowing or the like or an insufficient energy (output torque) due to a tie-up or the like and as a correction amount, to the predetermined value a1 of the input shaft rotational speed. The calculated correction amount is subtracted from the torque reduction amount _Tca set in the step (S53). That is, the actual rotation speed of the input shaft rotation speed Nt is detected by the input shaft rotation speed sensor 5, and the actual rotation speed (in FIG. 10, the upward side by blowing is denoted by N _U, and the downward side by tie-up is denoted by N _D ), and a target input shaft rotation speed (rotation based on the gear position) calculated based on the input torque and the like by the vehicle speed sensor 6, the speed gear ratio (4-2nd gear ratio), the throttle opening sensor 3, and the like. the difference between the linear line) N _TA to completion from the change start Δ
Nd is calculated. It should be noted that the difference ΔNd _{1 from} the ascending side N _U acts as a plus side with respect to the torque reduction amount, and the difference ΔNd ₂ from the descending side N _D acts as a minus side.
Then, the rotation difference ΔNd [= N _TA −N _U (or N _D )] is multiplied by the acceleration gain and the engine inertia amount to be converted into energy (that is, output torque by a coefficient) and supplied from the engine at that time. the calculated torque difference corresponding to the difference between the energy actually supplied to the target energy to be, the said value, the set torque reduction amount T is subtracted from _ca the engine control amount T _c is calculated .

Then, the torque reduction amount _Tca based on the energy difference from the engine in step S53.
Is repeatedly performed until the elapsed time t _E from the point when the shift progress rate reaches a1 [%] exceeds a predetermined time t ₁ set in advance. The predetermined time t ₁ is at the end of the feedback control of the disengagement hydraulic pressure PA (the step S20) and the end control of the engagement hydraulic pressure PA (the step S46), that is, when the shift progress degree ΔN of the input shaft speed is a2
[%] (Steps S21 and S27, for example, 90
[%]), When the downshift is substantially achieved, and the input shaft speed is shifted to the low speed (second speed) gear stage, or when the input shaft speed is stabilized in consideration of the increase in the input shaft speed due to acceleration. And the time t _E from the start of the engine control control is set to the predetermined time t.
_{When 1} has elapsed (T _E > t ₁ ), the above-described correction control based on the supply energy of the engine is stopped, and the release-side hydraulic pressure PA (and the engagement-side hydraulic pressure PA) are also controlled by the completion control (step S24). , S48) are started (S5).
4).

Here, by referring to the value of the flag of the shift determining means 1e, the mode determining means 1d performs a normal downshift (first mode) in which the currently performed downshift is a single downshift. It is determined whether or not there is (S
55). In the step S55 when it is determined that the normal downshift employ a preset reference time for a period of time t _2B as the time t ₂ as a return time of the torque reduction (S56). The engine control T _c is reduction amount corrected in the step S53 is swept up by the time t _2B (S60), while avoiding the upheaval of the engine output change, the engine output, the driver's accelerator pedal After returning to the normal value based on the opening degree sensor 3 (S61), the engine torque control ends.

On the other hand, if it is determined in step S55 that the shift is not a normal downshift, the mode determining means 1d is determined by the value of the flag of the shift determining means 1e referred to above.
Is determined to be a downshift during the upshift (second mode) or a downshift immediately after the next downshift (third mode) (S5).
7). If this judgment is a downshift in the upshift substitutes preset time t _2C as the time t ₂ as a return time of the torque reduction (S5
8). This time t _2C is longer than the reference time t _2B . Also by the judgment, if the downshift to the next Daunshifu is ahead is performed immediately after substitutes preset time t _2A as the time t ₂ as a return time of the torque reduction (S59). This time t _2A is shorter than the reference time t _2B . If a downshift is being performed during an upshift and a downshift is being performed immediately before the next downshift, the process proceeds from step S57 to step S59 (priority is given to prevention of a feeling of acceleration loss).

As described above, step S58 or S59
Also, after each step S58 and S59 is completed, the engine control _Tc returns to step S53.
Reduction amount corrected is swept up by the time t _2C or time t _2A at (S60), while avoiding the upheaval of the engine output change, the engine output is usually based on the accelerator pedal opening degree sensor 3 of the driver (S61), and the engine torque control ends. The control in steps S55 to S61 (the return control means 1
f (corresponding to FIG. 1) will be described later in detail.

The output torque T _O of the automatic transmission is
By the feedback control of the release hydraulic pressure PA, the pressure is maintained at a substantially constant value until the downshift (for example, the 4-2 shift) approaches completion, but the input shaft rotation speed _NT increases and the low speed due to the downshift is increased. As the number of revolutions approaches the side gear (for example, the second speed), the torque tends to rise relatively sharply and increase excessively until the torque value converges to the torque value after the downshift. Therefore, when the predetermined shift change before downshifting completion (ΔN = a1 [%]) , reducing the output from the engine at reduction amount T _ca calculated by the input shaft acceleration dN ₁ at that time. Thus, the generation of the peak torque due to the output torque is suppressed.

However, the end control of the engagement side hydraulic pressure PB (S41 to S46) is delayed, or the synchronization timing of the release side and the engagement side is delayed due to a mistake in the feedback control of the release side hydraulic pressure PA (S20). Or
Engine blowing may occur. In such a case,
The constant (torque reduction amount _Tca ) cannot keep up with the above-mentioned constant value, and the output (output) torque T _O generates a large blow as shown by a thin dashed line in FIG. 10 to generate a large shift shock. Therefore, in the present embodiment, the torque corresponding to the extra energy which is calculated based on the difference [Delta] nd ₁ and the actual rotational speed N _U between the target rotational speed N _TA of the input shaft, the said reduction amount T _ca Is added to
Engine torque T _c, as indicated by a dashed line, is corrected as described above reduction amount T _ca increases, reducing the supply of energy from the engine to cause engine racing, thereby the output (output) torque T _{As for O} , the peak amount on the rising side decreases as indicated by the thick dashed line.

On the other hand, while the torque capacity of the disengagement side frictional engagement element does not decrease and the torque capacity of the engagement side frictional engagement element increases, tie-up occurs or the feedback control of the release side hydraulic pressure (S20). If the synchronization timing of the disengagement side and the engagement side is shifted to the gear stage before the shift (the side where the gear ratio is not established) due to a mistake, and the energy supplied from the engine is excessively consumed, becomes insufficient supply of energy in the torque reduction amount T _ca, output (output) torque T _O, as indicated by the thin dotted line in FIG. 10, caused excessive depression, discomfort, such as the brake is applied to the driver give. Therefore, in the present embodiment, the target rotation speed _NTA of the input shaft and the actual rotation speed N _D
Torque corresponding to the calculated is insufficient energy based on the difference [Delta] nd ₂ and is, is subtracted from the reduction amount T _ca,
The engine torque _Tc is corrected so as to reduce the amount of reduction as indicated by the dotted line, and compensates for the insufficient energy, thereby producing an output (output) torque Tc.
_O reduces the drop in torque, as shown by the thick dotted line.

The details of the control in steps S55 to S61 will be described. FIG. 11 is a time chart according to the engine torque control, and shows an outline of the engine torque control. The torque reduction amount in FIG. 11 is a control command from the engine control means 1c of the control unit 1, and indicates the maximum value of the engine torque to be controlled. Therefore, when the torque reduction amount is equal to or less than the detected engine torque, the engine torque is suppressed to the torque reduction amount. Further, when the torque reduction amount is larger than the detected engine torque, the torque reduction control for the engine torque is not executed. Corresponding to step S54 of FIG. 9 described above, in the portion indicated time t ₁ in FIG. 11, the torque reduction amount is equal to or less than the engine torque detected, the torque reduction is performed. Then, in response to step S55~S60 of FIG. 9 described above, in the portion indicated by time t _2A or time t _2B or time t _2C in FIG. 11, the torque reduction amount is greater than the engine torque is detected, the engine The torque increases in each of the predetermined sweep times.

FIG. 12 is a time chart relating to engine torque control during a downshift during an upshift. This control corresponds to step S57 in FIG.
This corresponds to control at time _t2C of one. When the driver returns the accelerator pedal, the so-called off-up shift,
For example, in the state where the throttle opening degree θ is constant, the input shaft torque _Tt is substantially constant, and the input rotation speed _Nt is reduced based on the upshift, during the 4-5 shift, and the driver open the throttle opening depresses the accelerator pedal in terms of SL _1, thereby the input shaft torque T _t starts to increase from iT ₁ point in FIG. Based on the throttle opening, the control unit 1 determines downshift based on the map and issues a downshift command. The input shaft rotational speed N _t is switched to increase in terms IR ₁ in FIG. (Rotation change start point of the downshift).

[0047] By the hydraulic pressure control by the downshift is operated, it is started aforementioned torque reduction control (step S53~S54 in FIG. 8), the torque reduction amount TR is reduced at a point TR ₁ in FIG. Input shaft torque is temporarily reduced from the viewpoint IT ₂ in FIG accordingly. Aforementioned torque reduction amount T _ca a predetermined time t ₁
The input shaft torque _Tt is maintained in the reduced state, and accordingly, the input shaft torque _Tt is also maintained in the reduced state. Thereafter, the control of the return control means 1f, a torque reduction amount in terms TR ₂ in the figure, it starts to rise at a predetermined slope on the basis of the above-mentioned return sweep time T _2C (line a in the figure). Also the input shaft torque T _t accordingly starts increasing at a point IT ₃ in the drawing, the throttle opening from the start of the rise after a predetermined time t _2C theta
(The line b in the figure).

In FIG. 12, for comparison, the torque reduction amount TR in the case of normal downshift control is shown.
And changes in the input shaft torque _Tt . Also in the case of the normal downshift control, the torque reduction amount is maintained in the reduced state for the predetermined time t ₁ , and accordingly, the input shaft torque is also maintained in the reduced state, and then the torque reduction amount is reduced at the point TR ₂ in the drawing. , The return sweep time t _2B
Starts rising at a predetermined inclination based on. However, in the case of the normal downshift control, the ascent starts with a slope indicated by a line a ′ in the figure (a slope steeper than the slope indicated by the line a in the figure). Also the input shaft torque T _t accordingly starts increasing at a point IT ₃ in the figure, the line with the slope shown by the slope even line b in FIG. A steeper slope than the slope indicated with b in Fig. ' Will be Then, a predetermined time t _2B (time t _2C
(Shorter) later, the input shaft torque according to the throttle opening is obtained.

FIG. 12 shows a change in the output shaft torque during a downshift during the upshift and a change in the output shaft torque in the case of normal downshift control. In the downshift during the upshift, the downshift is performed from a state in which the torque is suppressed from the normal level by the off-up shift. Therefore, if the input shaft torque is controlled to increase sharply as shown by the line b ′ in the figure without considering this, the output shaft torque T _O becomes the line A ′ in the diagram.
A peak is created as shown by, and vibration occurs. However, in the present embodiment, the return time of the torque reduction is extended as shown by the time _T2C , and the input shaft torque _Tt is controlled so as to gradually increase as shown by the line b in the figure. _{Since the} peak of _O is suppressed as shown by the line A in the figure, the end shock is prevented.

FIG. 13 is a time chart relating to the engine torque control in the case where a downshift is performed immediately before the next downshift is performed. This control corresponds to step S59 in FIG. 9 and corresponds to the control at time _t2A in FIG. As the driver keeps depressing the accelerator pedal, the throttle opening is opened,
The control unit 1 determines a downshift based on the map,
Issue a downshift command. Thus downshift it is started, the input shaft rotation speed N _t continues to increase, also increased input shaft torque T _t, the torque reduction control in this state (step S53~S54 in FIG. 8) is started by the torque in response to the reduction amount TR is lowered, the input shaft torque T _t is lowered from iT ₁ point in FIG.
Then, the torque reduction amount is maintained at a predetermined time t ₁ decreases state, even if the input shaft torque T _t in accordance with this is maintained in a degraded state, the output torque T _O is lowered state accordingly. During this time, when the driver continues to depress the accelerator pedal, the throttle opening is in the open state, and the control unit 1 determines the next downshift based on the map, and the value of the flag relating to the next shift process is decreased. This indicates a shift.

[0051] Then, the torque reduction amount in terms TR ₁ in the figure, it starts to rise at a predetermined slope based on the return sweep time T _2A (line a in the figure). Also the input shaft torque T _t accordingly starts increasing at a point IT ₂ in the figure is the input shaft torque corresponding to the throttle opening from the start of the rise after a predetermined time t _2A (in FIG. Line b).
Moreover the reduced torque reduction amount entered the subsequent downshift, the input shaft torque T _t is lowered from the point IT ₃ in FIG accordingly. Thereafter, under the control of the return control means 1f, the torque reduction amount decreases as shown by the line c in the figure, and accordingly, the input shaft torque also decreases as shown by the line d in the figure, and then returns.

FIG. 13 shows, for comparison, changes in the torque reduction amount and the input shaft torque in the case of normal downshift control. Also in the case of the normal downshift control, the torque reduction amount becomes equal to the predetermined time t.
_After the input shaft torque is maintained in the reduced state for _{1 and} the input shaft torque is also maintained in the reduced state accordingly, the torque reduction amount increases at a predetermined slope based on the return sweep time T _2B at the point TR ₁ in the figure. To start. However, in the case of the normal downshift control, the ascent starts at an inclination shown by a line a 'in the figure (a gentler inclination than the inclination shown by the line a in the figure).
This input shaft torque starts increasing at a point IT ₂ in chart according to this inclination also performed with the slope indicated by line b 'in Fig. The slope loose than the slope indicated by the line b in FIG. Then, after a predetermined time t _2B (longer than the time t _2A ) from the start of the increase, the input shaft torque according to the throttle opening is obtained. Further, since the torque reduction control relating to the subsequent downshift is delayed by the difference between the time t _2B and the time t _2A , as described above (see FIG. 10), the input shaft rotation speed N _t
, The amount of torque reduction TR controlled by the difference from the target value is delayed as indicated by the line c ′ in the figure, whereby the input shaft torque _Tt is delayed as indicated by the line d ′ in the figure.

FIG. 13 shows a change in the output shaft torque T _O when a downshift is performed immediately before the above-described downshift, and a change in the output shaft torque when a normal downshift control is performed. In the case of further downshifting during the downshift, if a long time is taken for the torque reduction, the increase in the output shaft torque is delayed as shown by the line A ′ in FIG. 13 and the feeling of acceleration is impaired. This is because a long time such as the time _t2B is required to return from the torque reduction, so that the input shaft rotation speed does not easily increase as indicated by the line B 'in the figure. Therefore, in the present embodiment, the return time of the torque reduction is shortened as time _T2A , and the input shaft rotation speed is easily increased as shown by the line B in the figure, so that the increase of the output shaft torque is accelerated. As a result, good output control is realized without impairing the feeling of acceleration.

In the above-described embodiment, the downshift mode is only three in the case of performing the torque return control from the reduction control. However, the case is not limited to the three cases, and the downshift mode may be two. For example, the first mode and the second mode, or the first mode and the third mode, or four or more modes are possible. It may be determined restoration soup time t ₂ according to the characteristics of each mode in any case. Note that return from reduction control is not limited to the return soup time t _2, it may be controlled by the speed and sweep gradient like.

When returning the input shaft torque in the torque reduction control (step S55 in FIG. 9).
To S61), the difference between the actual torque and the required torque may be large. For example, if there is a downshift command during an upshift as described above,
Reduction control is performed in an upshift, and subsequently, a downshift reduction command is output. In this case, for example, by a control command on the engine side such as based on exhaust gas, the amount of torque reduction by the reduction control during the upshift gradually increases, and the actual input shaft torque also gradually increases. If the input shaft torque is reduced by a predetermined reduction amount by the reduction control based on the downshift, the difference from the required torque becomes too large. If the difference is large, the sweep of the torque return deviates from the actual torque, which may cause a shock. Therefore, it is preferable to eliminate the shock by performing the return sweep of the input shaft torque not from the reduction amount due to the downshift, but from the actual torque during the upshift, for example.

The release-side and engagement-side hydraulic controls are not limited to the above-described embodiment, but may be other controls. In the engine torque control, a reduction amount based on the input shaft acceleration was used as a reference value and was corrected for the reference value. However, without setting the reduction amount, an engine based on a normal driver accelerator pedal opening was used. The torque may be used as a reference value to correct the torque.
Further, the excess energy such as blowing and the energy shortage due to tie-up are calculated based on the difference between the target value and the actual value of the input shaft rotation speed.
The calculation may be performed based on other factors such as the difference between the target value and the actual value of the output torque. Further, the reduction amount by the engine torque control may be set to be substantially constant without controlling the target value of the input shaft speed by the difference from the actual value as described above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electronic control unit according to the present invention.

FIG. 2 is a diagram schematically showing a hydraulic circuit.

FIG. 3 is a time chart of an input shaft rotation speed, a release hydraulic pressure, and an engagement hydraulic pressure command based on a gear ratio indicating a power-on downshift.

FIG. 4 is a flowchart illustrating control of a release-side hydraulic pressure of a downshift.

FIG. 5 is a flowchart showing a continuation of FIG. 4;

FIG. 6 is a flowchart showing control of the engagement side hydraulic pressure of the downshift.

FIG. 7 is a flowchart showing a continuation of FIG. 6;

FIG. 8 is a flowchart showing engine torque control according to the present invention.

FIG. 9 is a flowchart showing a continuation of FIG. 8;

FIG. 10 is a time chart related to engine torque control.

FIG. 11 is a time chart related to engine torque control.

FIG. 12 is a time chart related to engine torque control in a downshift during an upshift.

FIG. 13 is a time chart relating to engine torque control when a further downshift is performed during the downshift.

[Explanation of symbols]

Reference _{Signs List} 1 control unit 1b torque difference detection means 1c engine control means 1d mode determination means _NTA target value (input shaft speed target value) _Tca reference value (reduction amount)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 11/10 F02D 11/10 K 29/00 29/00 H 41/04 310 41/04 310G F16H 61 / 02 F16H 61/02 // F16H 59:18 59:18 59:24 59:24 59:42 59:42 59:44 59:44 59:72 59:72 (72) Inventor Seiwa Nomura Anjo City, Aichi Prefecture 10 Takane, Fujiimachi F-term (reference) in Aisin AW Co., Ltd. CB08 DA06 DB01 DB05 DB09 DB11 DB23 EA09 EB03 EC02 EC04 FA04 FA10 FA11 FB01 FB02 3G301 JA00 JA04 KB10 LA03 LC03 LC08 NA08 NC04 ND01 NE01 NE06 NE17 NE19 NE23 PA11Z PF01Z PF03Z PF07Z PF08Z 3J552 MA02 MA02 NA01 A32Z VA48Z VB01Z VC01Z VC03Z VD01Z

Claims (4)

[Claims] An automatic transmission for shifting an engine and an input rotation from an output of the engine by switching a transmission path by connecting and disconnecting a plurality of friction engagement elements, and outputting the changed rotation to an axle. Wherein the automatic transmission is downshifted, wherein the automatic transmission is downshifted. In the downshift, an engine control means for reducing and controlling an output torque from the engine; and Mode determination means for determining what state the shift is in during a series of shift operations; and return control means for changing return from reduction control by the engine control means based on the determination of the mode determination means. A shift control device for an automobile. 2. The method according to claim 1, wherein the mode determination unit includes a first mode in which the downshift is performed alone and a second mode in which the downshift is performed during the upshift. As a return sweep time, when the mode determination means determines the first mode, a reference time is employed, and when the second mode is determined, a time longer than the reference time is employed. The shift control device for an automobile according to claim 1. 3. The mode determination means has a first mode that is a single downshift, and a third mode that is a downshift immediately before the next downshift, The control means uses the reference time when the mode determination means determines the first mode as the return sweep time, and uses the reference time when the third mode is determined as the return sweep time. The shift control device for an automobile according to claim 1, wherein the shift control device employs: 4. An engine control means for detecting and calculating an excess amount and an insufficient amount of torque supplied from the engine to the automatic transmission with respect to a target value; If the torque calculated based on the detecting means is excessive, the extra torque is reduced with respect to the reference value of the engine output torque, and if the calculated torque is insufficient, the shortage is reduced with respect to the reference value. The vehicle shift control device according to any one of claims 1 to 3, wherein the reduction control is performed so as to apply the required torque.