JP3327154B2 - Anti-creep device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a delay start feeling given to a driver by commanding release of engine output reduction control for preventing engine racing following the delay of time for engagement of a friction element from a creep prevention slipping condition, in an early timing within the range of no hindrance. SOLUTION: By raising an oil pressure Pc in the forward clutch, which has been left in creep preventive slipping condition since accelerating instant t1 , re-engagement of the clutch is processed and the oil pressure Pc is brought to the maximum value at the engagement completion time t2 . By such engagement, a turbine revolving speed Nt drops and becomes zero in the instant t2 . Judging that re-engagement is commenced in the instant Ts the torque converter slip quantity, which is the difference between the engine revolving speed Ne and the turbine revolving speed Nt , is increased to a set value A, a command to release engine output reduction control, which fully opens a sub-throttle value fully closed for preventing racing, is issued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a creep preventing device for an automatic transmission for preventing a creep phenomenon of an automatic transmission caused by drag transmission of a fluid transmission device.

[0002]

2. Description of the Related Art In an automatic transmission, since the engine rotation is input via a fluid transmission, the drag torque of the fluid transmission is stopped during a stop in a state where the power can be transmitted with the automatic transmission in a travel range. Causes a so-called creep phenomenon that causes the vehicle to run at a low speed. The driver operates the brakes to prevent this very slow running, but during this time,
Fuel economy is likely to deteriorate and vibration problems are likely to occur.

[0003] Therefore, by lowering the operating oil pressure of the hydraulically operated friction element to bring the automatic transmission into a state in which power can be transmitted in the traveling range, the operating friction element is brought into a slip state. There has been proposed a creep preventing device that reduces transmission of creep torque by a fluid transmission device.

[0004] In the creep prevention device,
By depressing the accelerator pedal at the start of the vehicle, when the engine is switched from the no-load state to the load state, the frictional element in the slip state is re-engaged by increasing the operating oil pressure to end the creep prevention control, Thereafter, the automatic transmission is set to a state where a predetermined power transmission is possible by setting the operating hydraulic pressure to the maximum value.

FIG. 7 is a time chart showing the operation when the friction element in the slip state is re-engaged. As shown by the solid line in the figure, the brake switch is switched from ON to OFF by releasing the brake, and the idle switch is turned on by depressing the accelerator pedal.
Instant t ₁ switch to OFF from raising the working oil pressure P _c of the friction element by a predetermined shelf pressure [Delta] P.

[0006] The predetermined shelf pressure [Delta] P, slip as the re-engagement state was friction element progresses, instant t ₁ the turbine speed N _t is output, which is the rotation speed of the hydraulic power transmission ~t
Decreased as shown by the solid line between the _two, eventually by refastening the friction element instantaneously t ₂ is completed, the turbine speed N _t is approximately zero.

[0007] the engine speed N _e one hand, inherent response delay from depression instant t ₁ of the accelerator pedal (e.g. 1
(About 50 msec), and rises as shown by the solid line with a gradient corresponding to the degree of depression of the accelerator pedal.

The moment t when the re-fastening of the friction element is completed
Slip friction element by a maximum hydraulic pressure P _c of the friction element ₂ completely prevented, rise and transmission output shaft speed N shown by the solid line in turbine speed N _t at the instant t ₂ after _The vehicle can be started as is apparent from the upward trend indicated by the one-dot chain line of _o , and is apparent from the upward trend indicated by the solid line of the transmission output shaft torque.

When the operating oil pressure _Pc of the friction element rises with a large response delay as shown by a broken line due to, for example, air being mixed into the operating hydraulic line of the friction element, As shown by the two-dot chain line, the operating oil pressure _Pc of the friction element is doubled due to the double cause such as the viscosity of the operating oil increasing at low temperatures, in addition to air mixing into the operating hydraulic line of the element. be elevated further with a large response delay, will the engine rotational speed is racing, the result dashed and chronological changes and instability shown by two-dot chain line in turbine speed N _t as transmission output of shaft torque dashed and 2 As is apparent from the unstable time-series change indicated by the dashed line, a large refastening shock occurs, and the commercial value of the automatic transmission is significantly reduced.

The delay in raising the operating oil pressure _Pc is not limited to the above, and the operating oil pressure _Pc is excessively lowered beyond the slipping state due to the failure of the creep prevention control, so that the opening state (the so-called in-fill state). Even when the creep prevention control is terminated by depressing the accelerator pedal in the state of (defective state), the above-described infill defect occurs.

Therefore, conventionally, for example, Japanese Patent Application Laid-Open No. Sho 62-2447
As described in Japanese Unexamined Patent Application Publication No. 25-205 and Japanese Unexamined Patent Publication No. Hei 3-82638, when the increase in the operating oil pressure _Pc is so delayed that the engine speed can be idle, the engine output is reduced to reduce the idle speed. Techniques have been proposed to prevent this and to prevent re-fastening of the friction element.

[0012]

[Problems that the Invention is to Solve the engine output reduction control in this case starts from the anti-creep control end command instant t _1, as shown in FIG. 8 that describes moved to the solid line waveform in FIG. 7, re-engagement of the friction element There to terminate completed instantaneously t ₂ becomes the turbine speed N _t is approximately 0, not be dispelled concern the following problems arise.

[0013] That is, for example, the re-engagement completion instant t ₂ of the friction element will be described of determining the shelf pressure ΔP to time adjusted to increase the start of the engine speed N _e, the engine speed N _e is the accelerator pedal depression instant to begin to rise after a specific response delay from (creep prevention control end command instant) t ₁ (for example, about 150 msec), re-engagement completion target time corresponding from instant t ₁ to the inherent response delay Δ
t ₁ (150 msec or so) just instantaneously t ₂ has elapsed, the turbine rotational speed refastened friction element has completed N _t is approximately 0
become. Therefore, as shown in FIG. 8, the above-described engine output reduction control starts from the instant t ₁ and ends at the re-fastening completion target time Δt.
To time t _{2 to 1} (about 150 msec) has elapsed is performed.

[0014] Thus, even if commanded end of the engine output reduction control is instantaneously t _2, actually the engine output begins to return towards a value corresponding to the accelerator pedal operation, the engine speed N _e and the turbine rotation as it is clear from the upward trend indicated by the broken line in several N _t, from the instantaneous t ₂ response delay time Delta] t ₂ (about 150 msec) is the instantaneous t ₃ when has elapsed. Therefore, according to the conventional apparatus, the actual engine output from depression instant t ₁ of the accelerator pedal starts to rise, Delta] t ₁ (about 150 msec) and Delta] t ₂ after also about 300msec is the sum value of (about 150 msec) However, it greatly exceeds 50 msec which begins to feel delay physically,
There is a concern that the driver may be dissatisfied with the fact that depressing the accelerator pedal does not easily accelerate.

According to the first aspect of the present invention, the engine output reduction control for preventing the engine from idling is substantially required until the friction element starts re-fastening. As described above, based on the fact that there is a delay in the recovery response of the engine output, there is no problem even if the termination of the engine output reduction control is commanded. The main purpose is to solve the problem. The invention according to claim 1 is further configured such that the confirmation of the start of re-fastening of the friction element can be accurately performed even when the engine speed changes due to the idle-up control of the engine accompanying the start of the engine driving auxiliary machine, Another object of the present invention is to improve the control accuracy.

According to the first aspect of the present invention, in addition to the above, the completion of the re-fastening of the friction element is timed by the start of the increase in the engine speed due to the depression of the accelerator pedal, so that the re-fastening of the friction element is too late. It is also an object of the present invention to prevent a start delay from occurring and a re-engagement shock due to premature re-engagement of the friction element.

It is another object of the present invention to realize engine output reduction control with a more inexpensive configuration.

[0018]

According to a first aspect of the present invention, there is provided a creep preventing device for an automatic transmission according to a first aspect of the present invention, in which rotation of an engine is input via a fluid transmission device, and selective hydraulic pressure of a plurality of friction elements is provided. It is used in an automatic transmission that shifts and outputs the engine rotation at a speed selected by operation, and reduces the operating oil pressure of the friction element during operation in order to reduce transmission of creep torque by the fluid transmission device. Thus, the friction element is brought into the slip state, and after the engine is switched from the no-load state to the load state, the operating oil pressure is increased to re-engage the friction element in the slip state, thereby performing creep prevention control. At the same time, the creep prevention of the automatic transmission is designed to reduce the output of the engine in order to prevent the engine from blowing due to a delay in response to the re-fastening. In the device, the fact that the friction element has actually started to re-engage due to the rise of the operating oil pressure is detected by the slip amount of the fluid transmission device having become equal to or larger than a set value, and the start of the re-engagement is detected. Upon detection, the engine output reduction control release command is issued, and immediately after switching from the no-load state to the load state of the engine, the operating oil pressure of the friction element is changed. The load is increased by a target shelf pressure such that re-engagement is completed in response to the start of the increase in the engine speed due to the release of the engine output reduction control accompanying the switching from the load state to the load state. It is characterized in that the operating oil pressure of the friction element is increased to a maximum value.

According to a second aspect of the present invention, there is provided the automatic transmission creep preventing apparatus according to the first aspect of the present invention.
The engine output reduction control is performed by a sub-throttle valve that is provided in series with a main throttle valve that is linked to accelerator pedal operation and that reduces engine output for traction control that prevents wheel drive slip. It is characterized by having done.

[0020]

The automatic transmission shifts and outputs the rotation of the engine from the fluid transmission at the gear selected by the selective hydraulic operation of the plurality of friction elements.

On the other hand, the creep preventing device, when reducing the transmission of the creep torque by the fluid transmission device, lowers the operating oil pressure of the friction element during the operation to bring the friction element into a slip state, thereby preventing a predetermined creep. Do.

After the engine is switched from the no-load state to the load state, the creep preventing device re-engages the friction element in the slip state by increasing the operating oil pressure to terminate the creep preventing control. When the engine blows due to a response delay of the re-fastening, the engine output is reduced to prevent the engine from blowing and the re-fastening shock of the friction element due to the engine output.

In the first aspect of the present invention, when the engine output reduction control is terminated, the fact that the friction element has actually started to be re-engaged due to the increase in the operating oil pressure is determined by the slip amount of the fluid transmission device being set to a predetermined value. When the re-engagement start is detected, the release command of the engine output reduction control is issued when the re-engagement start is detected. As compared with the conventional device that generates the friction element, the release of the engine output reduction control can be hastened by the time from the start of re-fastening of the friction element to the completion of re-fastening, and accordingly, the response to the switching from the no-load state of the engine to the load state To speed up the rise of the engine output, eliminating concerns that the driver may be dissatisfied with depressing the accelerator pedal. Door can be.

Further, in the first invention, the start of refastening of the friction element is detected by detecting that the slip amount of the fluid transmission device has exceeded a set value, so that the output rotation speed of the fluid transmission device decreases. The engine speed (input speed of the fluid transmission) increases due to the idle-up control of the engine accompanying the start of the engine drive accessories, etc., and the fluid transmission Even when the output rotational speed increases, the start of re-fastening of the friction element can be accurately detected, and the above-described effects can be more reliably achieved.

When the friction element starts re-fastening, the above-mentioned incomplete filling state causing the above concern has been eliminated, and the engine output is actually reduced from the release command of the engine output reduction control. Because there is a response delay before recovery, as described above, even if the engine output reduction control is canceled at the start of re-engagement of the friction element, the engine output is restored before re-engagement of the friction element is completed. It was confirmed that the above-mentioned timing of the engine output reduction control cancel command according to the first invention did not substantially matter.

In the first invention, in addition to the above, immediately after the engine is switched from the no-load state to the load state, the operating oil pressure of the friction element is used for switching the engine from the no-load state to the load state. In response to the release of the engine output reduction control, the engine shelf speed is increased by a target shelf pressure at which the re-engagement is completed in time with the start of the increase of the engine speed, and the working oil pressure of the friction element is set to the maximum value when the re-engagement of the friction element is completed. To ensure the completion of re-fastening of the friction element,
It is possible to time the start of the increase in the engine speed by canceling the engine output reduction control in response to the switching of the engine from the no-load state to the load state, and the re-engagement of the friction element is too slow, causing a start delay, It is possible to prevent the re-fastening of the friction element from occurring too early and causing a re-fastening shock.

In the second aspect of the present invention, the engine output reduction control is provided in series with a main throttle valve linked to the operation of an accelerator pedal to reduce the engine output for traction control for preventing wheel drive slip. In the case of a vehicle equipped with a traction control device, the above-described engine output reduction control can be performed by diverting the traction control sub-throttle valve. It can be realized by an inexpensive configuration.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram showing a creep preventing device for an automatic transmission according to an embodiment of the present invention. In the present embodiment, the anti-creep device 10 of the automatic transmission includes a forward clutch (start clutch) 11, which is a starting friction element to be engaged in the first forward speed of the automatic transmission, in a semi-engaged state (slip state). To prevent creep.

In FIG. 1, reference numeral 12 denotes a torque converter (fluid transmission), which comprises a pump impeller 12p, a turbine runner 12t, and a stator 12s.
The torque converter 12 is provided with a pump impeller 12p.
To the engine crankshaft 13, the turbine runner 12 t to the input shaft 14 of the automatic transmission, and the stator 12 s to the one-way clutch 1 on the transmission case 15.
It is a normal one that is put into practical use by putting it through 2o.

Here, the torque converter 12 transmits the engine rotation (rotation speed _Ne ) from the crankshaft 13 to the input shaft 14 of the automatic transmission while increasing the torque via the internal working fluid. The input rotation speed to the machine is _Nt .

The automatic transmission includes a plurality of friction elements (not shown) including a forward clutch 11, and selectively operates a plurality of friction elements including the forward clutch 11 with a corresponding hydraulic gear (engagement). Is to select.

In the present embodiment, the forward clutch 1 is engaged while the vehicle is stopped with the automatic transmission in the travel range to set the automatic transmission to the first forward speed selection state.
To a 1 to perform anti-creep in the semi-engaged state (slip state), the oil pressure modulator 16 to control the hydraulic pressure P _C of the forward clutch 11
Is provided.

The oil pressure modulator (hereinafter, referred to as OPM) 16 is provided with a line pressure P of the automatic transmission.
_L is supplied from the oil passage 17 to the input port 18, the output port 19 is connected to the operating hydraulic chamber 11 a of the forward clutch 11 via the oil passage 20, and has a drain port 21. ) 23 an electromagnetic force to act in the figure left by the output pressure of the port 19 via the port 22a to the chamber 24 facing the other end of the spool 22, i.e., is fed back to hydraulic pressure P _C of the forward clutch 11.

[0034] Such OPM16 as source pressure line pressure P _L to the input port 18, and functions as a linear solenoid valve which produces the hydraulic pressure P _C which corresponds to the electromagnetic force corresponding to the current value i _X to the solenoid 23, the the oil passage of the hydraulic pressure P _C 20
To the operating hydraulic chamber 11a of the forward clutch 11 as the operating pressure of the forward clutch. Here, the forward clutch 11 can generate the fastening force proportional to hydraulic pressure P _C.

The current value i _X to the solenoid 23 is controlled by a control unit 30, and a signal from an input sensor group 31 described later is supplied to the control unit 30.

The control unit 30 is a vehicle-mounted type using a microcomputer, and has an input circuit 151, a RAM 152, a ROM 153, a CPU 154,
It is assumed that the circuit includes a clock circuit 155 and an output circuit 156.

The input circuit 151 is a circuit that converts an input signal from each sensor of the sensor group 31 into a digital signal that can be processed by the CPU 154 and inputs the digital signal. RAM1
Reference numeral 52 denotes a readable and writable memory for writing an input signal from each sensor, writing information being calculated by the CPU 154, and reading the written information.
Further, the ROM 153 is a read-only memory,
Information and the like necessary for the arithmetic processing in U154 are stored in advance, and the information is read out by a command from the CPU 154 as necessary.

The CPU 154 is a device for performing arithmetic processing on various types of input information in accordance with predetermined processing conditions. The CPU 154 performs input information processing in creep prevention control, forward clutch operation control, and the like.
Is a circuit for setting the calculation processing time in the CPU 154. The output circuit 156 controls the solenoid 23 as an actuator based on a calculation result signal from the CPU 154.
Is a circuit that outputs a control current signal i _X to the control signal.

The output circuit 156 further outputs a control signal to a traction control device (TCS) 40 for preventing wheel drive slip based on the calculation result from the CPU 154. Published by Automobile Co., Ltd.
ISSAN CIMA) Introduction of FGY32 type car "
A sub-throttle valve controller 41 for controlling the opening of a sub-throttle valve (not shown) disclosed as a second throttle valve on page 6, page B-29 and page C-90, and amplifies the signal from the controller. A driving circuit 42;
An actuator 43 driven by the amplified signal from the drive circuit to drive the sub-throttle valve.

Although the sub-throttle valve is not shown, the sub-throttle valve is arranged in series with the main throttle valve of the engine that is linked to the accelerator pedal, so that the wheels do not generate a drive slip and the traction control is not required. In this case, the engine is fully opened, the engine output is determined only by the opening of the main throttle valve, and when a wheel slips, the opening of the sub-throttle valve is made smaller than the opening of the first throttle valve according to the degree of the driving slip. Then, predetermined traction control is performed.

For this reason, the sub-throttle valve controller 41 determines the degree of the drive slip on the basis of the wheel speed signal of each wheel, and calculates the degree of opening of the sub-throttle valve necessary to prevent the drive slip. Drive circuit 4
2 outputs a signal corresponding to the calculation result to the actuator 4
3 to adjust the opening of the sub-throttle valve to an opening that matches the calculated value, thereby preventing a drive slip.

Sub throttle valve controller 41
When the engine output reduction control command for creep prevention and the engine output reduction control release command described later are input from the output circuit 156 in addition to the traction control, the sub-throttle valve is fully opened in response to these signals. From the fully closed state and vice versa.

In the present embodiment, as sensors constituting the input sensor group 31, a select position switch 161,
Idle switch 162, oil temperature sensor 163, output shaft speed sensor 164, engine speed sensor 165, turbine speed sensor 166, and brake switch 16
7 is used.

The select position switch 161 is a switch for outputting a signal corresponding to the selected range (selected position) of the automatic transmission. In the present embodiment, the switch is turned ON when the selected range is in the neutral range (N range). ,
The selected range is the driving range (drive range; D range)
It is assumed that the switch is turned off and the switch signal _PSW is output only when.

The switch signal _PSW output from the select position switch 161 indicates that the range has been switched from the N range to the D range (N → D select operation has been performed). It is used as a signal to be performed.

The idle switch 162 is a switch for detecting whether or not the throttle valve of the engine is in a fully closed state (idle state). When the throttle valve is in an open state (engine load state), the switch is turned off, and is fully closed ( Only when the engine is in a no-load state), a switch signal Id based on the ON signal is output.

The oil temperature sensor 163 detects the transmission operating oil temperature (A
TF temperature) _Tm is a sensor that detects the oil temperature signal T
_Atf is output, and the output shaft speed sensor 164 is a sensor for detecting the speed No of the transmission output shaft. A signal output from the output shaft speed sensor 164 is used as a signal representing the vehicle speed.

The engine speed sensor 165, the rotational speed of the crankshaft 13 is a sensor for detecting the (engine speed) N _e, the turbine speed sensor 166, the rotation speed of the transmission input shaft 14 (turbine speed) a sensor for detecting the N _t.

The brake switch 167 is disposed on a brake pedal or the like, and is a sensor for detecting the operation of a foot brake or a side brake, and outputs a brake operation signal B when the brake is operated.

The CPU 154 executes the main routine of FIGS. 2 and 3 and the subroutine of FIG. 4 based on the input information from the input sensor group 31 to execute the creep prevention control and the start control from creep prevention as follows. It should be done as follows.

First, in step 51 of FIG. 2, the signals P _SW , Id, T
_m, N _o, B reads, in step 51,
A determination is made as to whether or not the vehicle is in the travel range (D range) based on the presence or absence of the signal _{PSW. If} the vehicle is in the travel range, the control proceeds to step 53, and if not, the control proceeds to step 57 to perform normal travel control. .

In step 53, it is determined whether or not the idle switch is in the idle state based on the presence or absence of the signal Id.
If it is in the idle state, the control proceeds to step 54, and if it is not in the idle state, the control proceeds to step 57 to perform normal traveling control.

In step 54, it is determined whether or not the brake is ON based on the presence or absence of the signal B. If the brake is ON, the control proceeds to step 55, and if the brake is OFF, the control proceeds to step 57 to perform the normal traveling control. Do.

[0054] At step 55, the vehicle speed to determine whether the vehicle is stopped in (transmission output shaft speed) N _o is approximately 0, if N _o is approximately 0, the sub-throttle valve is fully closed at step 58 with the outputs a command to the controller 41, starts the operation of the anti-creep control at step 56, performs normal running control complete the N _o almost not 0 control to step 57.

Eventually, the sub-throttle fully closing operation and the operation of the creep prevention control in steps 58 and 56 are started because of "running range, idling state, brake ON,
Only when all four conditions of "vehicle speed are substantially zero" are satisfied, otherwise, normal traveling control is performed.

Here, the reason why the sub-throttle fully closing operation is performed simultaneously with the start of the creep prevention control is that the main throttle valve is fully closed since the idle state, so that even if the sub-throttle valve is fully closed. This is because there is no hindrance, and if the sub-throttle valve is changed from fully open to fully closed so as to prevent the occurrence of idling of the engine due to the delay in the engagement of the forward clutch 11 when starting, the responsiveness deteriorates.

[0057] The In anti-creep at step 56, first, the working oil pressure P _c of the forward clutch 11, so as to abruptly to the initial setting pressure determined within a range in which the clutch does not slide out, a current value i _X of the solenoid 23 determined, then working oil pressure P _c is determined current value i _X to the solenoid 23 so as to gradually decrease at a predetermined gradient until the slip start clutch, the instantaneous after is expressed as output rotational speed difference of the torque converter 12 torque converter slip amount is a constant value that (e.g., about 50 rpm) for determining the current value i _X to the solenoid 23 to control the hydraulic pressure P _c to be kept.

As described above, the operating oil pressure _Pc is rapidly reduced to the initial set pressure, and then gradually reduced at a predetermined gradient until the forward clutch 11 starts to slip, so that the forward clutch 11 is quickly slipped without releasing shock. , The creep prevention can be started with a high response, and thereafter, the feedback control of the operating oil pressure _Pc so that the torque converter slip amount is maintained at a constant value can realize the reliable creep prevention. .

After executing step 56, the control proceeds to step 61 of the start control program shown in FIG.
In step 61 of FIG. 3, the signal from the idle switch 162 Id, signal N _o from the output shaft speed sensor 164,
The signal B from the brake switch 167 is read, and in the next step 62, it is determined whether or not the idle switch is in the idle state (engine no load state) based on the presence or absence of the signal Id. To step 63, and if the accelerator switch is in the idling switch OFF state (engine load state), control is passed to step 65, and control is performed when the accelerator is ON (when the engine is switched from the no-load state to the load state). The predetermined forward clutch re-engagement control (start control) is performed as described later with reference to FIG.

In step 63, it is determined whether or not the brake is ON based on the presence or absence of the signal B. If the brake is ON, the control proceeds to step 64, and if the brake is OFF, the control proceeds to step 66 to determine whether the brake is ON. Is performed.

[0061] At step 64, it is determined whether or not the vehicle speed N _o is approximately 0, the control if N _o approximately 0 back after the step 61, the control When larger than N _o approximately 0 Step Proceeding to 66, the forward clutch re-engagement control at the time of accelerator OFF is performed.

After all, it is the case that “the creep prevention control is in operation and the idle state”, and the “brake OF
F or N _o > 0 ”, step 6
In step 6, the forward clutch re-engagement control is performed when the accelerator is turned off. In this forward clutch re-engagement control, the forward clutch 11 is gently engaged.

This forward clutch re-engagement control is repeated until it is determined in the next step 67 that the engagement of the forward clutch has been completed. The determination of the forward clutch engagement completion, have when they become turbine speed N _t is approximately 0, or, turbine speed N
difference between _t, and multiplying value of the gear ratio i when the output shaft speed N _o and the forward clutch engagement (Nt-N _o · i)
Is substantially zero, it is determined that the fastening is completed.

In step 68, which is performed when the forward clutch engagement is completed, in which the determination in step 67 is YES, and after step 65, in which the forward clutch re-engagement control is performed when the accelerator pedal is ON, the operation of the creep prevention control is performed. Is ended (OFF).

Next, the forward clutch re-engagement control at the time of accelerator ON, which is performed in step 65 of FIG. 3 according to the gist of the present invention, and the engine output for preventing the engine from blowing due to a response delay of the re-engagement The reduction control will be described. This process is as clearly shown in FIG. 4, and as shown in FIG. 6, an instant t _{1 at} which the idle switch 162 is switched from ON to OFF in response to the accelerator ON operation (in FIG. 6, the brake switch 167 is also switched from ON to OFF). be initiated indicated) as being, first in step 71, it reads the engine speed N _e and the turbine speed N _t, respectively.

[0066] In the following step 72, the engine speed N _eS and the turbine rotating at the instant t ₁ of each of these read engine speed N _e and the turbine speed N _t, the accelerator ON operation (anti-creep end command) It is stored as a number N _tS .

In step 73, as shown in FIG. 6,
In determining the re-engagement target time Δt _1, which determines how much time is required to change the forward clutch 11 from the slip state for creep prevention to the re-engagement completion state,
1 operating cycle of the engine (intake stroke, a compression stroke, explosion stroke, exhaust stroke) and the constant A ₀ which represents the time corresponding to said engine speed of the anti-creep end command at t ₁ N _eS
, The re-fastening target time Δt ₁ is obtained by the calculation of Δt ₁ = A ₀ / _NeS .

The target re-engagement time Δt ₁ here corresponds to a response delay (about 150 msec) from the creep prevention end command time t ₁ (instantaneous depression of the accelerator pedal) until the engine speed actually starts increasing. This is a time aimed at completing re-engagement of the forward clutch 11 in synchronization with the start of the increase in the engine speed.

[0069] In step 74, just instantaneously t ₂ which refastened target time Delta] t ₁ of the passes as in FIG. 6,
Complete re-engagement of the forward clutch 11 computes the target shelf pressure ΔP such that the turbine speed N _t to substantially zero. The target shelf pressure ΔP has a turbine system inertia torque of the torque converter 12, since it is proportional to the sum value of the stall torque, stall torque ratio can determined from the turbine inertia I _t, the torque converter performance diagram illustrated in FIG. 5 ΔP = [(I _t) using t _S, stall torque capacity coefficient τ _S , engine speed _Nes and turbine speed N _tS at creep prevention termination command time t ₁ , target re-fastening time Δt ₁ , and constant B.・ N _tS / Δt ₁ ) +
(T _S τ _{S Ne S} ² )] · B.

[0070] In step 75, the OPM current i _X anti-creep control is being as shown in FIG. 6, the target shelf pressure Δ
The current value Δi corresponding to P is added and output, and
Holding the OPM current i _X to the value 6, the holding, turbine speed N _t read at step 77, continues until instant t ₂ of FIG. 6 is determined to have become almost zero in step 80 that Accordingly, as shown a hydraulic pressure P _c of the forward clutch 11 in FIG. 6, between the instant t ₁ ~t _2, it is increased by the target shelf pressure [Delta] P.

As a result, the forward clutch 11 is re-engaged from the slip state before the instant t ₁ , and the turbine speed _Nt gradually decreases. And reaches the forward clutch 11 is completed refastening instant t ₂ to the turbine speed N _t to approximately 0, step 80 advances the control to step 81 and 82, forward as at the instant t ₂ after the 6 the OPM current i _X to the hydraulic pressure P _c of the clutch 11 to the maximum value in the maximum value, to completely prevent slipping of the forward clutch 11.

As described above, the target re-engagement time Δt ₁ corresponding to a response delay from the instant t ₁ when the accelerator pedal is depressed until the engine speed actually starts increasing.
Just instant t ₂ but that passes, to a targeted shelf pressure ΔP to substantially zero refastening is complete turbine speed N _t of the forward clutch 11, as shown in FIG. 6, up start of the engine Timed forward clutch 1
The re-engagement of the forward clutch 11 is completed, so that the re-engagement of the forward clutch 11 is delayed to cause a start delay, and the re-engagement of the forward clutch 11 is unnecessarily too fast to cause a re-engagement shock. Can be.

However, air was mixed into the forward clutch operating pressure circuit, the hydraulic oil viscosity increased due to low temperature, or the forward clutch 11 was released beyond the slip state due to poor creep prevention control. Time
As described above with reference to FIG. 7, the operating oil pressure _Pc causes a delay in rising, and the re-engagement of the forward clutch 11 does not proceed as described above, and a large re-engagement shock of the forward clutch 11 occurs with the engine running idle. Would.

In this embodiment, the engine output reduction control for avoiding the engine idling is performed as follows. That is, reads the engine speed N _e and the turbine speed N _t in step 77 of FIG. 4, in a next step 78, represented by the rotational speed difference between these engine speed N _e and the turbine speed N _t The slip amount ΔN of the torque converter 12 is calculated from ΔN = N _e −N _{t, and} it is determined whether or not the slip amount ΔN has reached the instant t _S in FIG.

Here, the slip amount setting value A is a slip amount for determining whether or not the forward clutch 11 has started re-engagement (incomplete filling), with an allowance for preventing erroneous determination. For example, about twice as much as 50 rpm, which is the slip amount for preventing creep (about 100 rpm)
It is good to set.

Until the torque converter slip amount ΔN does not reach the set value A until the instant t _{S in} FIG.
There By so proceeding to step 80 the control skips step 79, to enable the full closing command of the sub-throttle valve at step 58 in FIG. 2, Until refastened initial instant t _S, the sub-throttle The engine output reduction control for fully closing the valve is executed. With this engine output reduction control, even if the re-engagement of the forward clutch 11 is delayed due to the delay in the rise of the operating oil pressure _Pc , the engine does not run idle, and the re-engagement shock of the forward clutch 11 caused by this is prevented. be able to.

At step 78, after it is determined that the torque converter slip amount ΔN has become equal to or greater than the set value A, the control proceeds to step 88 through step 79 after the instant t _{S at which} re-engagement of the forward clutch 11 starts. , A command to fully open the sub-throttle valve is output to the controller 41. As a result, the output of the engine is determined in accordance with the opening of the main throttle valve linked to the operation of the accelerator pedal after the instant t _S , and the engine output reduction control is released.

Then, when an inherent response delay (about 150 msec) elapses from the instant t _S of the release command of the engine output reduction control, the engine is driven at the engine speed N _e and the turbine speed N _t indicated by a dashed line in FIG. , And the output of the transmission output shaft torque, as is evident from the rising waveform, to allow the vehicle to start.

Incidentally, the engine output recovery delay Δt ₃ from the instant t _{2 at which} the re-engagement of the forward clutch 11 is completed is
FIG. 8 is a short time corresponding to the time t _{1 to} t _S required to detect the start of re-engagement of the forward clutch 11.
Conventional engine output recovery delay Δt ₂ (150 msec
), And it is possible to eliminate the fear of giving the driver dissatisfaction that the driver does not easily start even if the accelerator pedal is depressed.

Note that after the instant t _S when the forward clutch 11 starts re-engaging, the incompletely packed state of the forward clutch 11 causing the start delay has been resolved, and the engine output reduction control is canceled. Since there is a response delay until the engine output is actually recovered from the command, as described above, the engine output reduction control is canceled (full opening of the sub-throttle valve) at the instant t _{S at} which re-engagement of the forward clutch 11 starts. even if the command is not the engine output before refastening complete instant t ₂ of the forward clutch 11 is restored, that virtually timing of the engine output reduction control release command according to the embodiments described above is a problem There is no.

The forward clutch 11 is re-engaged and opened.
When detecting the beginning, as shown by α in FIG.
Rotation speed N_tIs the instant t when the accelerator pedal is depressed₁At the time
Revolution N_tSThe re-fastening starts when the predetermined amount has dropped from
It can also be determined that there is. However, in this case, the instant t
₁Immediately after the
Engine speed N_eRose
Hour, turbine speed N _tReopening
There is a concern that the initial judgment may be incorrect.

In the above embodiment, the
Gin rotation speed N_eAnd turbine speed N _tAnd the deviation between
Based on the torque converter slip amount ΔN expressed as
And when this becomes larger than the set value A,
Since it is determined that the fastening has started, the instant t₁Immediately after
Such as idle drive up
Engine speed N_eThe torque converter
Has no significant effect on the motor slip amount ΔN.
The initial determination can be made accurately, and
Layers can be reliably achieved.

In the above embodiment, the engine output reduction control is provided in series with the main throttle valve linked to the operation of the accelerator pedal to reduce the engine output for traction control for preventing wheel drive slip. In the case of a vehicle equipped with a traction control device, the above-described engine output reduction control can be performed by diverting the traction control sub-throttle valve. Can be realized by a cheaper configuration.

[Brief description of the drawings]

FIG. 1 is a control system configuration diagram of an automatic transmission including a creep prevention device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a first half of a creep prevention control and a shift control program of the automatic transmission, which are executed by a control unit in the embodiment.

FIG. 3 is a flowchart showing the latter half of the control program.

FIG. 4 is a flowchart showing a subroutine relating to a forward clutch re-engagement process and an engine output reduction control for idling prevention in a creep prevention control program when an accelerator is turned on.

FIG. 5 is a performance diagram illustrating a performance curve of a torque converter.

FIG. 6 shows the forward clutch re-engagement processing and the engine output reduction control for idling prevention shown in FIG. 4 when the accelerator is turned on, the forward clutch operating oil pressure, the engine speed, the turbine speed, the transmission output shaft speed, and the speed change. 6 is a time chart showing a time-series change in machine output shaft torque.

FIG. 7 shows the conventional forward clutch re-engagement processing performed by the conventional creep prevention device when the accelerator is turned ON, when the forward clutch operating oil pressure has risen normally, when there is a moderate rise delay, and when there is a large rise delay. FIG. 7 is a time chart similar to FIG.

FIG. 8 is a time chart similar to FIG. 6, illustrating a forward clutch re-engagement process and an engine output reduction control for idling prevention when an accelerator is turned on by a conventional creep prevention device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Creep prevention device of automatic transmission 11 Forward clutch (friction element during operation) 12 Torque converter (fluid transmission device) 12 _p pump impeller 12 _t turbine runner 12 _S stator 13 crankshaft 14 transmission input shaft 16 oil pressure modulator 23 Solenoid 30 Control unit 31 Input sensor group 40 Traction control device 41 Subthrottle valve controller 42 Actuator drive circuit 43 Subthrottle valve actuator 161 Select position switch 162 Idle switch 163 Oil temperature sensor 164 Output shaft speed sensor 165 Engine speed sensor 166 Turbine Speed sensor 167 Brake switch

Continuation of the front page (56) References JP-A-5-65837 (JP, A) JP-A-61-278651 (JP, A) JP-A-3-82638 (JP, A) JP-A-63-163068 (JP, A) JP-A-60-220260 (JP, A) JP-A-63-188651 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 41/00-41/28 F02D 29/00-29/06 F02D 41/00-41/40 F16H 59/00-63/48

Claims (2)

(57) [Claims] 1. An automatic transmission which receives the rotation of an engine via a fluid transmission device and shifts and outputs the engine rotation at a speed selected by a selective hydraulic operation of a plurality of friction elements. In order to reduce the transmission of creep torque by the fluid transmission device, the operating oil pressure of the friction element during the operation is reduced to bring the friction element into a slip state, and the engine is switched from a no-load state to a load state. After that, the operating oil pressure is increased to re-engage the friction element in the slip state to terminate the creep prevention control, and to reduce the engine output to prevent the engine from blowing due to a delay in the re-engagement response. In the creep prevention device of the automatic transmission that is reduced, the fact that the friction element has actually started to re-engage due to the increase of the operating oil pressure, It is configured to detect when the slip amount of the fluid transmission device has become equal to or greater than a set value, and to issue a command to cancel the engine output reduction control when detecting the start of re-fastening. Immediately after switching from the state to the load state, the operating oil pressure of the friction element is increased, and the friction element starts increasing the engine speed due to the release of the engine output reduction control accompanying the switching of the engine from the no-load state to the load state. The automatic transmission is characterized in that it is configured to increase by a target shelf pressure such that re-engagement is completed in a timely manner, and when the re-engagement of the friction element is completed, the operating oil pressure of the friction element is increased to a maximum value. Anti-creep device. 2. The engine output reduction control according to claim 1, wherein the engine output reduction control is provided in series with a main throttle valve interlocked with operation of an accelerator pedal to reduce traction control for preventing wheel drive slip. A creep preventing device for an automatic transmission, characterized in that the device is configured to perform the control by a subthrottle valve.