JPH0656202B2 - Shift control device for automatic transmission for vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, which shifts based on a shift pattern.

(Prior Art) Generally, an automatic transmission is automatically shifted according to a shift pattern that is preset according to a running state of a vehicle, that is, a shift position is preset according to a vehicle speed and an engine load (throttle opening). The changed gearshift pattern is stored in the control unit, and the gearshift is controlled in accordance with this gearshift pattern. When setting the above-mentioned shift pattern, the output position of the engine, which has been previously examined under a certain condition, is taken into consideration, and the shift position is determined so as to obtain an appropriate running performance.

However, if there is a change in the outside air pressure between the flatland and highlands, or if the engine changes over time, the engine output will change, and the driving force input to the automatic transmission for actual vehicle travel will be In addition to such changes in the engine output, it also changes when a load is applied to the engine from auxiliary equipment such as an air conditioner. In these cases, the traveling performance is changed only by performing the shift according to the preset shift pattern.

For such a problem, for example, JP-A-60-23662
As disclosed in the publication, there is known a device that controls gear shift depending on high altitude and low altitude. This device detects altitude by the external atmospheric pressure and shifts gear according to the change of the altitude signal. I try to change the pattern. However, as described above, the factors that affect the driving force for running the vehicle include not only the external atmospheric pressure, but also various factors such as the change with time of the engine and the load applied to the engine from auxiliary machinery. The required running performance cannot be sufficiently satisfied only by changing the shift pattern according to only the element (external pressure). That is, as described above, the shift pattern is set on the basis of the engine output characteristic previously examined under a certain condition, so that even if the engine operating state (for example, throttle opening and rotation speed) is the same, the actual engine output May differ from the engine output examined in advance. Even in such a case, if the control is performed with the same shift pattern, the running performance will change (for example, when the air conditioner is ON, the shift is performed with a low engine output). ) Was a problem.

(Object of the Invention) In view of the above circumstances, the present invention provides an appropriate driving force for vehicle running regardless of any factors such as the external pressure, the change of the engine over time, and the load of auxiliary machinery. A shift control device for a vehicle automatic transmission capable of maintaining traveling performance.

(Structure of the Invention) The present invention relates to a vehicle equipped with an automatic transmission that shifts gears based on a shift pattern that is preset according to the running state of the vehicle, and a predicted value of the engine output according to the operating state of the engine at that time. And an engine output input to the automatic transmission, and changing means for changing the shift position according to the shift pattern according to the comparison result are provided.

With this configuration, when the torque input to the automatic transmission as the driving force for the actual vehicle running deviates from the predicted engine torque, whatever the cause, it compensates for the change in running performance. The shift pattern is corrected as described above.

(Embodiment) FIG. 1 shows the overall structure of an automatic transmission, an engine, and a control system for them. In the figure, 1 is an automatic transmission, 2 is an engine, and 3 is a control unit (ECU) that comprehensively controls the automatic transmission 1 and the engine 2. The automatic transmission 1 is composed of a torque converter, a gear transmission operated by hydraulic pressure, and the like, and a plurality of solenoid valves 4 incorporated in a hydraulic circuit are controlled by a control unit 3 so that gear shifting is performed. It has become. The automatic transmission 1 is provided with a vehicle speed sensor 5 for detecting the vehicle speed from the rotation of its output shaft, an inhibitor switch 6 for detecting the neutral and parking states, and a turbine speed sensor 7 for detecting the turbine speed of the torque converter. The signal from now on is input to the control unit 3.

On the other hand, for the engine 2, an intake passage 8 and an exhaust passage 9, a fuel system including a fuel injection valve 10 and a fuel pump 11, a spark plug 12, a distributor 13
And an ignition system including an igniter 14 and the like, and a throttle valve 15 is arranged in the intake passage 8. 16 is an air flow meter for detecting the amount of intake air,
Reference numeral 17 is a crank angle sensor attached to the distributor 13, 18 is a throttle opening sensor for detecting the opening of the throttle valve 15, and 19 is an O provided in the exhaust passage 9.
_Two sensors, and signals from these are also input to the control unit 3.

Further, the control unit 3 outputs a signal (1, 2, D range signal) 2 for designating the range of the first speed, the second speed or the automatic drive as a signal related to the automatic transmission 1.
1, a power mode or economy mode designating signal (P, E mode signal) 22, a kick down switch signal 23, an overdrive cut switch signal 24, etc. are input. In addition to this, various signals necessary for controlling the automatic transmission 1 and the engine 2 may be input to the control unit 3.

The control unit 3 responds to various inputs by
A signal for controlling the automatic transmission 1 is output to the solenoid valve 4, while signals for controlling the fuel system, the ignition system, etc. of the engine 2 are supplied to the fuel injection valve 10, the fuel pump 11, and the igniter 1.
It is output to 4 mag. Especially for the automatic transmission 1, the control unit 3 has means for storing a preset shift pattern 31 according to the running state of the vehicle and controlling the automatic transmission 1 based on the shift pattern 31. A change means 32 is provided for changing the shift position according to the shift pattern 31 according to the result of comparison between the predicted value of the engine output according to the operating state of the engine and the engine output input to the automatic transmission 1. In this embodiment, the control unit 3 controls the automatic transmission 1 and the engine 2 comprehensively, but the control engine 2 of the automatic transmission 1 is controlled by a separate control unit. Alternatively, communication may be performed between the control units as required.

The shift pattern 31 stored in the control unit 3 is, for example, as shown in FIG. 2, a basic shift position (gear position) from the first speed to the fourth speed depending on the vehicle speed and the throttle valve opening. Gear shift positions S _{1 to} S ₃ are set, and such a gear shift pattern itself has been conventionally known. Although FIG. 2 shows only one type of gear change pattern, normally, a plurality of kinds of gear change patterns such as a power mode for acceleration performance and an economy mode for economical traveling are set and stored. , The shift pattern is selected according to the P and E mode signals. Further, the shift pattern may be set such that the shift position is different between upshifting and downshifting.

Further, the changing means 32 has a shift position movement amount according to the difference between the predicted value Fe of the engine generated torque and the input torque Fm of the automatic transmission 1 as shown in FIG.
The gear shift pattern is corrected as shown in FIG. 5 or FIG. 5, which will be described in detail later.

FIG. 6 is a flow chart showing a concrete example of control mainly for the automatic transmission 1 by the control unit 3. This flowchart starts when the ignition switch (Ig) is turned on, and first performs initial setting in step S ₁ and then step S _{1.
At 2} , the various sensor information input to the control unit 3 is read. Next, in step S _3, and calculates a basic injection amount of fuel corresponding to the intake air amount and the like, a signal for controlling the fuel injection to output to the fuel control system (Step S _{3 ').} In Step S ₄ following step S _3, calculates a predicted value Fe of the engine torque from the map shown in FIG. 8 depending on the rotational speed n and the air flow meter output engine (or the intake air negative pressure). This predicted value Fe is set by being preliminarily examined from the engine torque characteristic, that is, the engine torque characteristic with the intake negative pressure as a parameter with the engine speed as the horizontal axis is as shown in FIG. 7, and the intake temperature and the like are constant. Under the conditions, the engine torque is determined by the engine speed and the intake negative pressure or the output of the air flow meter. Therefore, the engine torque examined under such a constant condition is set as the predicted value Fe, and as shown in FIG. Is stored in the control unit 3.

Next, in step S ₅ , the engine speed and the automatic transmission 1
With the turbine speed of the torque converter in
The slip rate e is calculated. The slip ratio e represents the ratio of the turbine speed to the engine speed in percentage. Then, in step S _6, examines whether the converter range (operating range in which the torque converter is performed) illustrated in FIG. 9, the determination result is NO, the flow proceeds to step S ₉ to be described later.

When the determination in step _{S 6} is YES, at step _{S 7,} and calculates the input torque Fm as follows. That is, as is generally known, there is a correspondence relationship between the slip ratio e and the specific input torque μ and torque ratio τ of the torque converter as shown in FIG. 9, and within the converter range shown in this figure. Then, from the ratio input torque μ, the torque ratio τ and the engine speed n, the input torque Fm
Is calculated as Fm = τ · μ · n ² . Therefore, [μ ・
The value of τ] is examined and stored in the control unit 3 as a map as shown in FIG.
In step S _7, the value and the engine speed n of the obtained from the map [mu · tau] in accordance with the slip ratio e, and to calculate the input torque Fm.

Next, in step S _8, the predicted value F of the engine torque
e and the input torque Fm of the automatic transmission 1 (Fe-F
m), the shift position movement amount is obtained, and the shift pattern is corrected based on this. In this case, for example, as shown in FIG. 3, when the difference (Fe-Fm) exceeds a predetermined permissible range, depending on whether the difference is positive or negative, the difference is increased to the high speed side or the low speed side. Set the corresponding shift position movement amount. Then, based on this, when the input torque Fm of the automatic transmission 1 is smaller than the predicted value Fe of the engine-generated torque as shown in FIG. 4 or 5, the shift positions S _{1 to} S _1
3 is shifted to the high speed side (broken line Sh, Sh '), the shift position _S 1 to S ₃ and when the input torque Fm is greater than the predicted value Fe is shifted to the low speed side (broken line Sl, Sl')
Thus, the shift pattern is modified. In this case, the entire shift position line may be moved as shown in FIG. 4, or the shift position may be moved within a range of frequently used loads excluding low load and high load as shown in FIG. Good.

Further, in step S _9, the above corrected speed change pattern (basic shift pattern if not corrected),
Find the gear according to vehicle speed and throttle valve opening,
The automatic transmission 1 to the speed and outputs a signal for driving performing shift control (step S _{9 ').} Then, repeat the following processing returns to step S _2.

According to the above control, the automatic transmission 1 is actually given to various factors due to various factors such as changes in the outside air pressure between flat and highlands, changes in the engine over time, and loads applied to the engine from auxiliary equipment such as an air conditioner. Even if the driving force for traveling the vehicle is changed, the shift pattern is corrected accordingly and the shift position is appropriately controlled.

That is, the basic shift pattern as shown in FIG.
It is planned that the characteristics of the engine output under the condition where the atmospheric pressure and the like are constant are considered in advance, and the engine output is directly transmitted to the automatic transmission 1 to be the driving force for running the vehicle.
Although it is set so that proper traveling performance is obtained, the traveling performance is affected if the driving force for traveling the vehicle changes due to various factors as described above.

When such a situation occurs, the actual engine torque deviates from the predicted value Fe if, for example, the change of the outside air pressure or the change of the engine over time occurs, and the load of auxiliary equipment such as an air conditioner is added. For example, since the input torque Fm of the automatic transmission 1 decreases, a difference occurs between the predicted value Fe and the input torque Fm regardless of any factor. Depending on this difference, the shift position is changed by treatment with the step S _8, the proper running state so that the shift pattern to be maintained is modified.

In this case, the influence of the decrease in the external pressure in the highlands, the change with time of the engine, the load on the auxiliary machinery, etc. usually causes the input torque Fm of the automatic transmission 1 to become smaller than the predicted value Fe. At this time, according to the basic shift pattern, insufficient power is felt during shifting. Therefore, the correction of the shift pattern according to the result of comparison between the predicted value Fe and the input torque Fm is performed by shifting the shift position to the high speed side at least when the input torque Fm becomes smaller than the predicted value Fe. do it.
In the present embodiment, the input torque Fm is further reduced due to special circumstances.
In consideration of the case where is larger than the predicted value Fe, in this case, the shift position is shifted to the low speed side.

In the above embodiment, the input torque Fm of the automatic transmission 1 is
Is calculated from the torque ratio τ obtained from the slip ratio e of the torque converter, the specific input torque μ and the engine speed n, but may be directly detected by a torque sensor.

Also, comparing the predicted value Fe with the input torque Fm,
The process for changing the shift position according to the comparison result does not always have to be performed, and may be performed only when the running state of the vehicle (vehicle speed and throttle valve opening) is near the shift position. .

(Effects of the Invention) As described above, the present invention compares the predicted value of the engine output according to the operating state of the engine with the engine output input to the automatic transmission that is the driving force for the actual vehicle traveling. ,
Since the shift position is changed according to the preset shift pattern according to the comparison result, the automatic transmission is changed to the above-mentioned automatic transmission due to any factors such as change of external pressure, change of engine with time, load of auxiliary machinery, etc. Even when the input engine output deviates from the predicted value, the gear shift pattern is corrected accordingly, and proper running performance can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention, FIG. 2 is a view showing an example of a shift pattern, and FIG. 3 is a shift position according to a difference between a predicted value of engine torque and an input torque of an automatic transmission. FIGS. 4 and 5 are explanatory views showing specific examples of gear shift pattern correction, FIG. 6 is a control flowchart, and FIG. 7 is engine torque according to engine speed and intake negative pressure. FIG. 8 is a diagram showing a map of the predicted value of the engine torque, FIG. 9 is a characteristic diagram of the ratio input torque and the torque ratio according to the slip ratio of the torque converter, and FIG. 10 is a characteristic value of the torque converter. It is a figure which shows the map of. 1 ... Automatic transmission, 2 ... Engine, 3 ... Control unit, 31 ... Shift pattern, 32 ... Change means.

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Claims (2)

[Claims] 1. A vehicle equipped with an automatic transmission that shifts gears based on a gear shift pattern that is preset according to the running state of the vehicle, and a predicted value of the engine output according to the operating state of the engine at that time and the automatic transmission. A shift control device for an automatic transmission for a vehicle, comprising: a change unit that compares an engine output input to a transmission and changes a shift position according to the shift pattern according to the comparison result. 2. The changing means changes the shift position to a high speed side when the engine output input to the automatic transmission is smaller than a predicted value of the engine output. A shift control device for an automatic transmission for a vehicle according to claim 1.