JPH0688561A - Torque-down controller of automatic transmission - Google Patents

Abstract

PURPOSE:To perform torque-down control optimally by judging whether accelerator operation from its full-close or from the intermediate opening, respectively at the time of down-shifting by means of this accelerator operation. CONSTITUTION:In time of down-shifting (S11), a starting time of torque-down control is detected on the basis of the speed ratio of a hydraulic torque converter (S12). When a starting point is detected, whether an accelerator is operated from its full-open or from the intermediate opening is judged. Here, at the time of being operated from the intermediate opening where a starting response of engine power torque is good enough, a larger value than the operation from the full-close is set up (S15, S16) as a retard value of ignition timing. When this retard value is set up according to the aforesaid pattern of the accelerator operation, the ignition timing is retarded according to the above-mentioned retard value as long as the specified time, and thereby the engine power torque is forcibly lowered (S17, S18).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque down control device for an automatic transmission, and more particularly to a technique for reducing gear shift shock in a downshift operation when the accelerator opening changes.

[0002]

2. Description of the Related Art An automatic transmission is proposed in which the output torque of an engine is forcibly reduced during a downshift operation in order to reduce a shift shock during a downshift that accompanies an accelerator opening operation and improve drivability. (See Japanese Patent Laid-Open No. 3-81539, etc.).

In the above torque down control, for example, the speed ratio of the fluid type torque converter (output rotation speed /
The time when the input speed decreases to a predetermined reference level (for example, 1.0) is used as the torque-down control start timing, and the ignition timing and fuel are controlled based on the predetermined torque reduction control amount set from the engine load and engine speed. The injection output is controlled to forcibly reduce the engine output torque, and when a predetermined time has elapsed from the start timing based on the speed ratio, it is determined that the torque down control has ended, and the torque down control is stopped ( (See FIG. 8).

Incidentally, in FIG. 8, the solid line shows the accelerator pedaling from the fully closed state, and the dotted line shows the accelerator pedaling from the intermediate opening degree.

[0005]

By the way, even during the same downshift, the response of the engine output torque differs between the case where the accelerator is opened from the fully closed state and the case where it is opened from the intermediate opening degree. The engine output torque rises better when the accelerator is opened from the opening.
Therefore, even if the torque down control is executed at a constant timing based on the speed ratio of the torque converter and based on the torque reduction control amount set based on the static operating condition of the engine as in the conventional art, Depending on how to open the accelerator, there is a problem that the gear shift shock cannot be satisfactorily reduced or excessive torque reduction control is performed.

Particularly, in an engine equipped with an exhaust turbocharger, the rise characteristics of engine output torque are significantly different between when the accelerator is opened from the fully closed state and when the accelerator is opened from an intermediate opening degree due to the occurrence of so-called turbo lag. However, there will be a large difference in shift shock during downshifting. The present invention has been made in view of the above problems, and it is possible to stably reduce the shift shock at the time of downshifting regardless of whether the accelerator is opened from the fully closed state or the intermediate opening degree. An object is to provide a torque down control device.

[0007]

Therefore, a torque down control device for an automatic transmission according to the present invention is configured to select a gear position based on at least an accelerator opening degree.
It is configured as shown in FIG. 1 or 2. In FIG.
The output torque reduction means is means for forcibly reducing the output torque of the engine, and the output torque reduction control means during shifting is the output torque reduction during a predetermined period during a downshift operation accompanying an increase in the accelerator opening degree of the engine. Operate the means.

Here, the torque decrease amount setting means changes the engine output torque by the output torque decreasing means when the accelerator opening increases from a fully closed state and when the accelerator opening increases from an intermediate opening. Set different drop control amounts. On the other hand, in FIG. 2, a torque reduction period setting means is provided in place of the torque reduction amount setting means, and the torque reduction period setting means is provided when the accelerator opening changes from fully closed and when the intermediate opening is performed. The predetermined period for operating the output torque reduction means by the output torque reduction control means at the time of shifting is set differently depending on the change in the accelerator opening from the degree.

[0009]

According to this structure, when the output torque of the engine is forcibly reduced during the predetermined period during the downshift operation accompanying the increase of the accelerator opening degree of the engine, the accelerator is opened from the fully closed state or the intermediate position. Different values are set as the control amount for reducing the engine output torque depending on whether the opening is made. This allows
It is possible to perform control in accordance with different engine output torque generation levels depending on whether the accelerator is opened from the fully closed state or the intermediate opening degree.

Further, by making the timing of executing the torque down control different depending on whether the accelerator is opened from the fully closed state or the intermediate opening degree, the rise response characteristics of the engine output torque can be dealt with to correspond to each. It is possible to execute the torque reduction control at the optimum time.

[0011]

EXAMPLES Examples of the present invention will be described below. In FIG. 3 showing the system configuration of the present embodiment, an automatic transmission 2 is connected to the output side of an engine 1 mounted on a vehicle (not shown). The automatic transmission 2 is connected to a fluid torque converter 3 interposed on the output side of the engine 1 via the fluid torque converter 3, and the engine output torque is transmitted via the torque converter 3. The transmission 4 (transmission mechanism) and a hydraulic actuator 5 for connecting / disconnecting various transmission elements in the gear type transmission 4 are provided. The operating hydraulic pressure for the hydraulic actuator 5 is on / off controlled via various electromagnetic valves (not shown).

Signals from various sensors are input to the control unit 6. As the various sensors, there is provided a potentiometer-type throttle sensor 8 for detecting an opening TVO (accelerator opening) of a throttle valve 7 which is provided in an intake system of the engine 1 and works in conjunction with an accelerator pedal (not shown). The throttle sensor 8 is provided with an idle switch 8a which is turned on when the throttle valve 7 is in the fully closed position.

A vehicle speed sensor 10 for detecting a vehicle speed VSP by obtaining a rotation signal from the output shaft 9 of the automatic transmission 2 is provided. The control unit 6 is, for example, a CPU for engine control (for fuel injection control or ignition timing control)
A dual-port RAM that is accessible from both CPUs and is an integrated type that incorporates an automatic transmission control CPU
Is used, and with this configuration, both CPs
The data calculated by U can be shared.
The engine control unit and the automatic transmission control unit may be separately provided so that they can communicate with each other.

In the automatic transmission control CPU of the control unit 6, the select lever operates in accordance with the drive position signal of the select lever operated by the driver.
(Range), the shift positions of the first to fourth speeds are automatically set in accordance with the throttle valve opening TVO (accelerator opening) and the vehicle speed VSP, and the gear type transmission 4 is set to the shift position via the hydraulic actuator 5. Controls automatic shift control.

That is, a shift pattern map is set in advance based on the throttle valve opening TVO (accelerator opening) and the vehicle speed VSP, and corresponds to the actual opening TVO and the vehicle speed VSP detected by the sensor. The gear position is obtained from the shift pattern map, and when the current gear position and the gear position selected from the map are different, the gear position is changed to the gear position designated by the map.

In addition to the automatic shift control as described above, in the present embodiment, in order to prevent the output torque (driving torque) at the output shaft 9 from suddenly changing during the gear shifting operation, a gear shift shock is generated. A control (torque down control) for forcibly reducing the engine output torque is performed by retarding the ignition timing (ignition advance value) in the ignition device 11 at the time of downshift due to depression. The ignition device 11 is a publicly known device including an ignition plug, an ignition coil, a power transistor, and the like.

The torque down control at the time of downshifting by depressing the accelerator pedal, which is performed by the control unit 6, will be described below with reference to the flow charts of FIGS. In this embodiment, the functions of the output torque reduction means, the output torque reduction control means during shifting, the torque reduction amount setting means, and the torque reduction period setting means are as shown in the flow charts of FIGS. 6 is provided as software.

The flowchart of FIG. 4 shows that the downshift due to the depression of the accelerator pedal is due to the depression of the accelerator from an intermediate opening at which the engine output torque rises with good response to the movement of the accelerator. A program for determining whether or not it is due to accelerator depression from a relatively blunt fully closed position is shown. First, step 1 (denoted as S1 in the figure. The same applies hereinafter).
Then, the detection results of the throttle valve opening TVO (accelerator opening) and the vehicle speed VSP are input.

In step 2, the throttle valve opening T
Downshift determination is performed based on VO and vehicle speed VSP. When the downshift is being performed, the routine proceeds to step 3, where the change rate ΔT of the throttle valve opening TVO immediately before is.
It is determined whether or not VO is greater than or equal to the predetermined value DTVOSL.

When the throttle valve 7 (accelerator) is suddenly opened at a rate equal to or higher than the predetermined value DTVOSL, the routine proceeds to step 4, where the opening operation is performed from the idle position (fully closed position). Determine whether or not. Specifically, the time required when it is assumed that the opening operation is performed from the fully closed position to the opening TVO at the present time with the detected opening change rate ΔTVO is calculated, and the idle switch 8a is actually moved by this time. Is ON, it is determined whether the accelerator pedal operation from the fully closed state is performed or the accelerator pedal operation is performed from the intermediate opening degree.

If it is determined in step 4 that the accelerator has been depressed from the fully closed position, the operation proceeds to step 5,
Determine the downshift state from the fully closed position. on the other hand,
Even if the accelerator pedal operation is performed from the fully closed position, if it is determined in step 3 that the accelerator pedal operation speed is relatively slow, and in step 4, not from the fully closed position, but from the intermediate opening degree. If it is determined that the accelerator pedal operation has been performed, the process proceeds to step 6 and it is determined that the accelerator pedal is down-shifted from the intermediate opening degree.

Here, the accelerator is suddenly opened,
However, if such an opening operation is performed from the fully closed position (idle position), the response of the engine output torque rises with a delay relative to the accelerator opening change. During operation (or when the accelerator opening operation is performed at a relatively slow speed), the engine output torque rises with a relatively good response.

Therefore, the torque down control at the time of downshifting by depressing the accelerator also needs to be performed in accordance with the above characteristics. Specifically, as shown in FIGS. The torque down control is executed with different characteristics depending on the accelerator operation pattern. The control shown in the flowchart of FIG. 5 shows an embodiment in which the control amount for reducing the engine output torque (retard amount of ignition timing) is set to different values according to the accelerator operation pattern.

Here, in step 11, it is judged whether or not it is a downshift due to depression of the accelerator pedal. If it is a downshift, proceed to the next step 12. Then, it is determined whether or not the speed ratio of the hydraulic torque converter 3 which has become 1.0 or more due to the downshift operation has become lower than 1.0, and the time when the speed ratio becomes lower than 1.0 is determined by the torque. It is detected as the starting point of down control.

When the starting point of the torque down control is detected based on the speed ratio of the fluid torque converter 3, the routine proceeds to step 13, where a timer for counting the execution time of the torque down control is started. Then step
At 14, the pattern of the accelerator operation detected in the flow chart of FIG. 4 is determined, and depending on whether the opening operation is from the fully closed state or the opening operation from the intermediate opening degree, step 15 or step 16 is performed. Selectively proceed to either.

In the present embodiment, the retard amount of the ignition timing according to the engine load and the engine rotation speed (the control amount for reducing the engine torque during downshift).
There are two pre-stored maps, one corresponding to the case where the accelerator is opened from the fully closed position and the other one corresponding to the case where the accelerator is opened from the intermediate opening. These two maps are selectively stored. Is used to determine the retard amount, a different retard amount is set for each of the two patterns of the accelerator operation, so that it is possible to cope with the difference in the required retard amount.

That is, compared with the case where the accelerator is opened from the fully closed state, the engine output torque rises more responsively when the accelerator is opened from the intermediate opening. Therefore, in order to reduce the shift shock due to the downshift, It is necessary to further reduce the engine output torque, and in the two maps that store the retard amount, the map corresponding to the case where the accelerator is opened from the intermediate opening is set to have a larger retard amount. It has become so.

Therefore, even if the rising characteristic of the engine output torque greatly differs depending on the accelerator operation pattern, the retard amount can be set according to the characteristic, and a shift shock of a different level occurs depending on the accelerator operation pattern. You can avoid that. In particular, in an engine equipped with an exhaust turbocharger, the rising characteristics of the output torque will be significantly different, but since the torque down control amount is made different according to the rising characteristics as described above, reduction of shift shock is stable. Can be done.

When the retard amount is determined based on the engine load and the engine speed at that time in either step 15 or step 16, in the next step 17, the ignition timing in the ignition device 11 is determined based on the retard amount. To forcibly retard the engine output torque. In the next step 18, it is determined whether or not the elapsed time from the start of the torque down control based on the speed ratio of the fluid torque converter 3 has reached a preset torque down control time, and the torque The engine output torque is reduced by retarding the ignition timing for the down control time.

By the way, as described above, when the accelerator pedal operation is performed from the intermediate opening degree, the engine output torque rises with a better response than when the accelerator pedal operation is performed from the fully closed state. Therefore, the torque down control is started. Also by increasing the speed, it is possible to execute the torque down control commensurate with the actual torque fluctuation. In this way, an example in which the start time of the torque down control is changed depending on whether the pedal is fully opened or the intermediate opening degree is used during the downshift by the accelerator pedal operation will be described with reference to the flowchart of FIG.

In the flowchart of FIG. 6, first, in step 21, it is determined whether or not it is a downshift accompanying the accelerator depression operation. When the downshift is being performed, the routine proceeds to step 22, where it is determined whether the accelerator pedal operation is performed from the fully closed state or the intermediate opening degree based on the detection result according to the flowchart of FIG.

Here, the speed ratio of the hydraulic torque converter 3 for determining the starting point of the torque down control is set to the vehicle speed V.
The map stored according to the SP is 2 of the accelerator operation.
It is set for each of the two patterns, and based on the determination result in step 22, proceeds to either step 23 or step 24, and searches the speed ratio for determining the starting point of the torque down control from the corresponding map. And ask.

In the two maps storing the speed ratio for determining the starting point of the torque down control, the speed ratio of the map corresponding to the accelerator depression from the intermediate opening at which the engine output torque rises with good response is higher. It is set so as to have a large value, so that when the output torque rises with good response, the torque down control can be started earlier.

When the speed ratio for determining the starting point of the torque down control is set for each of the two patterns of the accelerator depression operation in step 23 or step 24, in step 25, the set speed ratio and the actual speed ratio are set. The speed ratio of the fluid torque converter 3 is compared, and the start point of the torque down control is detected as the time when the speed ratio has dropped across the set value.

When the starting point of the torque down control is detected, the routine proceeds to step 26, where a timer for measuring the torque down control time is started, and then, at step 27, information on the engine load and the engine speed is obtained. The retard amount of the ignition timing is determined based on In step 28, the engine output torque is reduced by forcibly retarding the ignition timing based on the retard amount determined in step 27, and in the next step 29, the time measured by the timer is preset. It is determined whether or not the torque down control time has been reached, and torque down control by retarding the ignition timing is executed for a predetermined time.

As described above, in this embodiment, when the accelerator is depressed from the intermediate opening at which the engine output torque rises with good response, the period during which the torque down control is executed is longer than that when the accelerator is depressed from the fully closed state where the rise is relatively slow. Thus, the torque down control can be executed at a time corresponding to the actual torque generation characteristic. Also,
As described above, instead of changing the start timing of the torque down control for each of the two accelerator pedal depression patterns, the time for executing the torque down control is changed to change the rise characteristics of the engine output torque in the two patterns. You may make it correspond.

The flow chart of FIG. 7 is different from the flow chart of FIG. 6 only in that the processing contents in steps 23 and 24 are changed to the setting of the torque down control time (retard time), and the other steps of FIG. It is exactly the same as the flowchart. In the flowchart of FIG. 7, a map in which the torque down control time (retard time) is stored according to the vehicle speed VSP is used as a map when the accelerator depressing operation is performed from fully closed and when it is performed from an intermediate opening degree. It has two corresponding maps.

Then, in step 32, it is determined whether the accelerator depression operation is performed from the fully closed state or the intermediate opening degree. Based on the determination result, one of the two maps is selected, Determine the actual torque down control time. Here, since the response of the engine output torque is delayed when the accelerator is operated from the fully closed position, the torque down control is executed for a longer time when the accelerator is pressed from the fully closed position than when the accelerator is pressed from an intermediate opening. is there.

In the above embodiment, the torque down control is performed by the retard control of the ignition timing, but it may be performed by the fuel cut or the like, or by the combination of the fuel cut and the ignition timing retard. The configuration may be such that the engine output torque is reduced. Further, both the torque down control amount and the execution timing may be made different depending on whether the accelerator is depressed from the fully closed state or the accelerator is depressed from an intermediate opening degree.

Further, in the present embodiment, the start timing of the torque down control is detected based on the speed ratio of the fluid torque converter 3 and is ended after a predetermined time from the start, but the start and end are different parameters. It may be determined by.

[0041]

As described above, according to the present invention, the shift shock at the downshift accompanying the accelerator depression is caused regardless of whether the accelerator is opened from the fully closed state or the intermediate opening degree. There is an effect that it can be stably reduced.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing the configuration of the present invention.

FIG. 3 is a system schematic diagram showing an embodiment of the present invention.

FIG. 4 is a flowchart showing a pattern determination of an accelerator operation.

FIG. 5 is a flowchart showing an example in which the retard amount is varied depending on the accelerator operation pattern.

FIG. 6 is a flowchart showing an example in which the start timing is changed depending on the accelerator operation pattern.

FIG. 7 is a flowchart showing an embodiment in which the control time is changed depending on the accelerator operation pattern.

FIG. 8 is a time chart showing characteristics at the time of downshifting according to a conventional accelerator operation pattern.

[Explanation of symbols]

 1 Engine 2 Automatic Transmission 3 Fluid Torque Converter 4 Gear Transmission 5 Hydraulic Actuator 6 Control Unit 7 Throttle Valve 8 Throttle Sensor 8a Idle Switch 9 Output Shaft 10 Vehicle Speed Sensor 11 Ignition Device

Claims (2)

[Claims] 1. A torque down control device for an automatic transmission configured to select a gear position based on at least an accelerator opening, the output torque lowering means for forcibly reducing the output torque of the engine, and the accelerator of the engine. An output torque reduction control means for operating the output torque reduction means during a predetermined period during a downshift operation accompanying an increase in the opening degree, an increase change in the accelerator opening degree from fully closed, and an accelerator from the intermediate opening degree And a torque decrease amount setting means for setting the decrease control amount of the engine output torque by the output torque decreasing means to be different depending on the change in the increase of the opening degree, and an automatic transmission characterized by the following: Torque down control device. 2. A torque down control device for an automatic transmission configured to select a gear position based on at least an accelerator opening, the output torque lowering means for forcibly reducing the output torque of the engine, and the accelerator of the engine. An output torque reduction control means for operating the output torque reduction means during a predetermined period during a downshift operation accompanying an increase in the opening degree, an increase change in the accelerator opening degree from fully closed, and an accelerator from the intermediate opening degree And a torque reduction period setting unit that sets a predetermined period for operating the output torque reduction unit by the output torque reduction control unit at the time of shifting when the opening degree increases and changes. Torque down control device for automatic transmission.