JP2932447B2 - Control device for automatic transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission for a vehicle, and more particularly to a control device for an automatic transmission for a vehicle which effectively reduces a shock when the one-way clutch is synchronized. Related.

[0002]

2. Description of the Related Art Various proposals have been made for techniques for reducing an engine output (engine torque) during a gear shift to reduce a gear shift shock.

[0003] Among them, in the case of a downshift in which the one-way clutch synchronizes (changes from the idling state to the engaged state), the output of the engine is increased at the same time as the shift is started, and then immediately before the one-way clutch synchronizes, the engine output is increased. There has also been proposed a technique in which the output is temporarily reduced, and then the engine output is gradually returned to a normal state (Japanese Patent Laid-Open No. Sho 64-64).
85844).

According to this technique, at the time of a downshift, the engine rotational speed is first increased rapidly to perform a quick shift, and the output of the engine is temporarily reduced immediately before synchronization of the one-way clutch to thereby reduce the speed of the one-way clutch. This is to suppress the peak of torque fluctuation occurring at the time of synchronization.

[0005]

However, in an automatic transmission having such a one-way clutch, when the state shifts from a power-off state (so-called coast state) to a power-on state (so-called drive state), the above-mentioned situation occurs. In spite of the fact that a shock occurs when the one-way clutch is synchronized with a mechanism similar to that of the downshift that has been performed, the fact is that "shifting is not performed", so the shock reduction measures have not been taken. .

The reason for this is that it is not preferable to reduce the engine output when it is unnecessary, so that it has to be limited to a certain period (necessary period) from the shift output. it is conceivable that. That is, for example, even if a predetermined period immediately before the one-way clutch is synchronized is detected based on the rotating state of the rotating member, the state may be maintained, and it is not clear whether the synchronization is truly reached. Therefore, even if it is determined that the one-way clutch has entered the state immediately before the synchronization, if the engine output is constantly reduced at this time, an output reduction that is not necessarily required may be performed. Become. For this reason, conventionally, the reduction of the engine output has been limited to only when a shift is involved, and not performed when no shift is involved.

The present invention has been made in view of such a conventional problem, and shifts from a power-off state to a power-on state without a shift while eliminating unnecessary engine output reduction. An object of the present invention is to provide a control device for an automatic transmission for a vehicle, which can appropriately reduce a shock caused by synchronization of a one-way clutch at the time, and solve the above-mentioned problem.

[0008]

SUMMARY OF THE INVENTION As shown in FIG. 1, the present invention relates to an automatic transmission for a vehicle which achieves a predetermined shift speed by a combination of a friction engagement device and an operating state of a one-way clutch. In the control device, power-on state determination means for determining whether the vehicle state is a power-on state, immediately before synchronization detection means for detecting whether the one-way clutch has entered a predetermined period immediately before synchronization, Engine output reducing means for reducing the engine output regardless of whether a shift has occurred, when the state is a power-on state and the one-way clutch is detected to be in a predetermined period immediately before synchronization. This solves the above problem.

[0009]

In the present invention, it is determined whether or not the vehicle state is a power-on state, and it is detected that the vehicle state is a power-on state and that the one-way clutch has entered a predetermined period immediately before synchronization. Sometimes the engine output is reduced.

The state where the one-way clutch is not synchronized is a state where the one-way clutch is in a neutral state, that is, a state where the driving force of the engine has not reached the wheels. Therefore, as long as it is detected that the vehicle state is the power-on state, it is considered that this idling state is surely canceled by the driving force from the engine, and the one-way clutch is eventually synchronized. Therefore, by multiplying the detection of the power-on state and the detection of a predetermined period immediately before the synchronization of the one-way clutch, it is possible to reduce the shock due to the synchronization of the one-way clutch regardless of the occurrence of the shift. Become.

The power-on state can be generally determined by the engine load (detected by the accelerator opening, throttle opening, intake pipe pressure, etc.) and the vehicle speed.
Of course, the determination can also be made by arranging a torque sensor on the output shaft of the engine or the input shaft of the automatic transmission and actually detecting the torque at this portion.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 shows an overall outline of a vehicle automatic transmission and an engine to which this embodiment is applied.

This automatic transmission includes a torque converter 20, an overdrive mechanism 40, and an underdrive mechanism 60 having three forward stages and one reverse stage as its transmission.

The torque converter 20 includes a pump 2
1, a turbine 22, a stator 23, and a lock-up clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carrier 41 of the planetary gear device in the overdrive mechanism 40.

In the overdrive mechanism 40, a planetary pinion 42 rotatably supported by the carrier 40 includes a sun gear 43 and a ring gear 4.
4 is engaged. A clutch C0 and a one-way clutch F0 are provided between the sun gear 43 and the carrier 41, and a brake B0 is provided between the sun gear 43 and the housing Hu.

The underdrive mechanism 60 is provided with two front and rear rows of planetary gear units. This planetary gear device has a common sun gear 61, ring gears 62 and 63, planetary pinion 6
4 and 65 and carriers 66 and 67.

The ring gear 44 of the overdrive mechanism 40 is connected to the ring gear 62 via a clutch C1. The link gear 44 and the sun gear 61
Is provided with a clutch C2. Further, the carrier 66 is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 7.
Connected to 0.

On the other hand, the carrier 67 and the housing Hu
A brake B3 and a one-way clutch F2 are provided between the sun gear 61 and the housing Hu, and a brake B2 is provided between the sun gear 61 and the housing Hu via a one-way clutch. Is provided with a brake B1.

The automatic transmission includes a transmission section as described above, and a throttle sensor 100 for detecting a throttle opening degree reflecting a load state of the engine 1;
The electromagnetic solenoid valves S1 to S3 in the hydraulic control circuit 106 are driven according to a preset shift pattern by an automatic transmission control computer 104A to which a signal from a vehicle speed sensor 102 or the like for detecting a vehicle speed is input.
Under the control, the combination of engagement of each clutch, brake, and the like is performed as shown in FIG. 3 to perform shift control.

In FIG. 3, a circle indicates that the clutch or the brake is engaged, and a circle indicates that the one-way clutch is engaged (synchronized) when the power is turned on.

The electromagnetic solenoid valves S1 and S2 are
The first to third speed states of the underdrive mechanism 60 are controlled, and the electromagnetic solenoid valve S3 controls the lock-up clutch 24 of the torque converter 20.

In FIG. 2, reference numeral 110 denotes a shift position sensor, which is operated by the driver.
A switch for detecting the position of D, R, etc., 112 is a pattern select switch for selecting E (economic running), P (parking running), etc., and 114 is a water temperature for detecting the temperature of the cooling water of the engine. Sensors are shown, 116 is a foot brake, and 118 is a brake switch for detecting the operation of a side brake.

In this embodiment, in addition to these input signals, the signal of the C0 sensor 120 for detecting the drum rotation speed of the clutch C0 is also input to the automatic transmission control computer 104A. .

The engine 1 is controlled by the engine control computer 104B to control the fuel injection amount, ignition timing, and the like. The engine control computer 104B reduces or returns the engine torque from the automatic transmission control computer 104A. A signal SG1 to the effect is input.

Engine control computer 104
B controls the engine 1 based on the signal SG1 from the automatic transmission control computer 104A so as to reduce or restore the engine torque based on the command.

It should be noted that a known configuration for reducing the engine output can be employed. For example, a method of delaying the ignition timing may be employed, or a configuration in which a sub-throttle valve is provided and opened and closed by a motor may be employed.

Next, FIG. 4 shows a control flow executed in the above embodiment.

First, at step 210, it is determined whether or not the current speed is the first speed or the second speed. This is because in the above-described automatic transmission, the one-way clutch idles when the power is off only at the first speed or the second speed. That is, when the power is turned off at the first speed or the second speed, the one-way clutch F1 or F2 idles. Therefore, when the power is turned on from this state, the one-way clutch F1 or F2 is turned on even if no shift occurs. A shock occurs when the one-way clutch F1 or F2 synchronizes. However, since such a problem does not occur in the third speed and the fourth speed, there is no room for applying the present invention,
Therefore, the gear position is determined here.

In step 220, it is determined whether or not the power is on. The determination of the power-on state can be grasped from, for example, a map of the vehicle speed and the throttle opening.
Alternatively, a more accurate determination can be made by providing a torque sensor on the output shaft of the engine or the input shaft of the automatic transmission and determining the power-on state from the value of the torque sensor.

In step 230, it is determined whether or not the one-way clutch (F2 for the first speed stage, F1 for the second speed stage) has entered a predetermined period before synchronization. Specifically, this determination is made based on the vehicle speed (output shaft rotation speed N0) × gear ratio i.
-It can be determined from the rotational speed Nc0 <ΔN1 of the clutch C0. Here, ΔN1 is a constant.

If it is determined that the one-way clutch F1 or F2 has entered a predetermined period before synchronization, the routine proceeds to step 240, where a command to reduce the output of the engine, for example, a command to retard the ignition timing is issued.

In step 250, it is determined again whether the one-way clutch is just before synchronization. This judgment is N0 × i
Judgment is made by -Nc0 <ΔN2. However, ΔN1> ΔN2.

If it is determined that the one-way clutch F1 or F2 is just before synchronization, the routine proceeds to step 260, where a timer is started, and if it is determined at step 270 that a predetermined time has elapsed, the routine proceeds to step 280. The return of the engine output is started.

As is apparent from this control flow, if the power is turned off halfway, immediately at step 280
And the return of the engine output is started. However, only when the engine output has already been reduced and a predetermined time has elapsed in step 270, the return of the engine output is started after the predetermined time has elapsed.

The reason why the state of the one-way clutch is detected twice in steps 230 and 250 is that there is a slight time lag from when the engine output reduction command is issued to when the engine output is actually reduced. Therefore, it is necessary to issue a command to reduce the engine output as soon as possible,
In order to match the decreasing period with the actual synchronization as much as possible, it is more accurate to use a timer started immediately before synchronization (as close as possible to synchronization). This is in order to respond to requests such as re-judgment and eliminating unnecessary engine output reduction as much as possible.

According to this control flow, regardless of the occurrence of a shift, the one-way clutch is changed from the idle state to the power-on state in the power-off state, and the shock generated when the one-way clutch is synchronized is effectively reduced. Can be prevented.

FIG. 5 qualitatively shows the effect of the above embodiment.

In FIG. 5, the broken line is the conventional one and the solid line is the present embodiment. Conventionally, the sudden rise of torque and the vibration caused by the torsional vibration of the drive system have occurred simultaneously with the locking of the one-way clutch, but in the present embodiment, since the engine torque is reduced immediately before the synchronization, the smoothness is obtained. Characteristics are obtained.

[0040]

As described above, according to the present invention, the one-way clutch is changed from the idle state (power-off state) to the power-on state irrespective of whether or not a shift occurs. An excellent effect is obtained in that the shock generated when synchronizing can be reduced without error (without performing unnecessary unnecessary reduction of engine output).

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is an overall schematic configuration diagram of an automatic transmission for a vehicle and an engine to which the present invention is applied;

FIG. 3 is a diagram showing engagement states of frictional engagement devices and a one-way clutch of the automatic transmission.

FIG. 4 is a flowchart showing a control flow executed by the apparatus of the embodiment.

FIG. 5 is a shift characteristic diagram qualitatively showing an effect of the embodiment device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine, F0, F1, F2 ... One-way clutch, 20 ... Torque converter, 40 ... Overdrive mechanism, 60 ... Underdrive mechanism, 104A ... Automatic transmission control computer, 104B ... Engine control computer, 120 ... Clutch C0 rotation speed sensor.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 29/00

Claims (1)

(57) [Claims] A control device for an automatic transmission for a vehicle, which achieves a predetermined shift speed by a combination of operating states of a friction engagement device and a one-way clutch, determines whether a vehicle state is a power-on state. On-state determining means; immediately before-synchronization detecting means for detecting whether or not the one-way clutch has entered a predetermined period immediately before synchronization; and a predetermined period when the vehicle state is in a power-on state and the one-way clutch is immediately before synchronization. A control device for an automatic transmission for a vehicle, comprising: an engine output reduction means for reducing an engine output regardless of occurrence of a shift when it is detected that the vehicle is engaged.