JP2626365B2 - Control device for automatic transmission - 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, and more particularly to a shift control based on shift line characteristics.

[0002]

2. Description of the Related Art An automatic transmission detects a running state of a vehicle and performs an automatic shift to a corresponding selected gear by selectively operating various friction elements. In the shift control, for example, the shift point is calculated so that the fuel consumption characteristics and the like are optimal according to the throttle opening (accelerator opening) indicating the engine load, which is a parameter required for the shift control, and the shift line characteristics set according to the vehicle speed. Thus, the control can be executed.

[0003]

However, when making a shift decision solely based on the shift line characteristics determined by the throttle opening and the vehicle speed, considering the following cases, the accelerator pedal is depressed. Occasionally, a sense of discomfort may occur or a shift shock may occur. In other words, when the shift line is determined uniformly by the accelerator opening and the vehicle speed and the shift is performed according to it, even if the driver wants linear acceleration, a significant acceleration due to the downshift will occur when the driver crosses the shift down line. This may cause a strange feeling to the driver. Especially,
When the vehicle crosses the down line in the kick down (K / D) region, a shift shock may be accompanied.

FIG. 7 shows a part of a typical shift point characteristic model diagram. In this case, the setting of the K / D region is set to 7/8 of the throttle opening TVO.
The broken line along VO7 / 8 indicates K / D in 2 → 1 shift
It is the down line of the area. Therefore, when the accelerator pedal is depressed so as to exceed this, the automatic one-time operation by the kick down is performed regardless of the case.
If the shift to the high speed is performed and such a downshift is performed even in a case where the step is not a sudden step like the case, it is difficult to smoothly perform acceleration by the shift shock at that time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for an automatic transmission which can prevent the occurrence of the above-mentioned discomfort or the like in gear shift control and can accurately reflect the driver's intention to accelerate. That is.

[0006]

According to the present invention, there is provided the following automatic transmission control apparatus. 2. Description of the Related Art In an automatic transmission that shifts to a predetermined gear position determined by an engine load and a vehicle speed, a detection unit capable of detecting a change amount of an intake air amount of an engine, and an output of the detection unit is used to determine an engine load and a vehicle speed. A shift control means including means for prohibiting a shift to the lower shift speed when an increase change amount of the engine intake air amount when a shift to a lower shift speed than the current shift speed is determined is equal to or less than a predetermined value. A control device for an automatic transmission, comprising:

[0007]

The shift control means shifts to the shift speed in accordance with the engine load and the vehicle speed, but shifts to a shift speed lower than the current shift speed based on the output of the detection means capable of detecting the change amount of the intake air amount of the engine. When the increase change amount of the engine intake air amount at the time when the shift is determined is equal to or less than a predetermined value, the shift inhibiting means inhibits the shift to the lower gear. Accordingly, when the driver desires linear acceleration, it is possible to accurately judge the linear acceleration and prohibit the shift to a lower shift speed. Suppress or prevent,
This enables smooth acceleration that matches the driver's intention to accelerate.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows an embodiment of the control device of the present invention, wherein 1 is an engine, and 2 is an automatic transmission. The automatic transmission 2 includes a torque converter, a transmission mechanism (gear train), and various friction elements such as a clutch and a brake. Further, the automatic transmission 2 is provided with a control valve 3, which forms a shift control hydraulic circuit,
A line pressure solenoid 4, a first shift solenoid 5, a second shift solenoid 6, and the like are provided. These solenoids 4
6 are respectively electronically controlled by a controller 7, which has a signal from a throttle sensor 8 for detecting a throttle opening TVO (engine load) of the engine 1,
In addition to a signal from a vehicle speed sensor 9 for detecting a vehicle speed VSP, a signal from an engine intake air amount sensor 10 for detecting an air amount Qa to be taken into the engine 1 is input. Here, the sensor 10 may be, for example, an air flow meter composed of a hot wire film type mass flow meter, which detects the amount of intake air, and converts the detected value to the value for an automatic transmission. (For A / T) Supply to the controller 7 which is a control unit.

The controller 7 includes an input detection circuit having a function of converting an input analog signal into a digital signal (A / D conversion), an arithmetic processing circuit, a shift control executed by the arithmetic processing circuit, A storage circuit storing an arithmetic program and the like for downshift prohibition control under certain conditions for shift determination correction based on the engine intake air amount of
A drive circuit or the like for supplying a drive signal to each of the shift solenoids 5, 6 and the like (both are not shown) performs shift control and the like based on the input information. The storage circuit stores shift point characteristic data (shift characteristics) determined by the throttle opening and the vehicle speed applied in upshifting and downshifting of the shift control, and engine intake air used in downshift prohibition control. The data of the set threshold value for the amount of change in the amount is also stored.

The controller 7 basically operates at the time of shifting,
According to the above shift characteristics, the optimal shift stage of the automatic transmission for the current driving condition is determined from the throttle opening TVO (accelerator opening) and the vehicle speed VSP, and the shift solenoids 5, 6 are turned on and off so as to obtain this shift stage. The control valve 3 applies the line pressure regulated by the solenoid 4 according to the duty ratio D to the selected friction element in the automatic transmission 2 in accordance with the ON / OFF of the shift solenoids 5 and 6. It is supplied as operating hydraulic pressure (fastening pressure), and the automatic transmission is selected by the operation (fastening) and non-operation (release) of these friction elements. The automatic transmission 2 inputs the output of the engine 1 to a differential gear at a gear ratio corresponding to the selected shift speed, and drives the left and right rear wheels via the gear to allow the vehicle to travel.

In the above-described shift control, the controller 7 executes a control with respect to a shift point determined by the throttle opening TVO and the vehicle speed VSP, using the amount of change in engine intake air when crossing the shift point as a parameter. . That is, the amount of change in the engine intake air is monitored based on the information from the sensor 10, and if the amount of change is equal to or less than a predetermined value, the downshift is prohibited to ensure smooth acceleration. The downshift prohibition control is also executed.

FIG. 3 is an example of a program flowchart which is a part of the shift control program executed by the controller 7 and which includes the above-mentioned downshift prohibition processing portion. Hereinafter, description will be made with reference to FIG.
Step 101 is a step of observing the crossing of the downshift line by depressing the accelerator pedal. In the example of the shift schedule of FIG. 4, this shows a 1 → 2 upshift line (solid line) and a 2 → 1 downshift line (dashed line) in the first and second speed portions of the shift diagram. However, in this step, for example, it is checked whether the situation is the case (a) or the case (b). Each of the above cases is shown in FIG.
As also shown in (b), case (a) is obtained from a state in which the accelerator pedal is relatively depressed with respect to (b) (throttle opening TVO is large).
Compared with (a), this corresponds to each step from the state in which the accelerator pedal is not depressed so much (throttle opening TVO is small). The latter is also an example of a state in which quick stepping is performed, but in any case, the state crosses a downshift line (in the illustrated example, a downline in a kickdown (K / D) region). Note that the broken line in FIG. 5B represents the change in the engine intake air amount in each of the cases (a) and (b) when the control is executed according to the present control example. The above step 101 is performed in any case.
If so, the process proceeds to step 102 and subsequent steps.

Step 102 is a process for introducing a switching parameter for downshift inhibition and permission. Here, as mentioned above, the amount of change in the engine intake air amount Qa at the time of the neighborhood {t} when the down line is crossed}
Calculate Qa. FIG. 6 shows the transition of the intake air amount Qa near the time of crossing the downshift line when the accelerator pedal is suddenly depressed and when the accelerator pedal is depressed slowly. Throttle opening T
After the change of VO, Qa changes, and the change ΔQa of Qa at a predetermined time Δt from the crossing of the shift line is large as shown in FIG. Step 102 calculates such a change amount △ Qa,
In the next step 103, it is determined whether or not the ΔQa value is larger than a predetermined value X. Here, the value X is a predetermined threshold value regarding △ Qa. In examining the output state of the engine, the amount of change in the engine intake air amount is further increased as in this control, rather than relying solely on the throttle opening TVO and the vehicle speed VSP to determine the output state of the engine.
By judging the output state of the engine based on Qa, the engine output state can be more accurately grasped (accurately grasping the load state of the engine), and therefore, even if the driver has the same throttle opening at the same vehicle speed. Even in a situation where the driver steps on the accelerator, it is possible to know a more accurate acceleration intention, including whether the driver is seeking linear acceleration or not. The threshold value X can be set from such a viewpoint.

If, as a result of the determination in step 103, the answer is YES and 成立 Qa> x holds, it is determined that the driver desires rapid acceleration by depressing the accelerator pedal at this time. That is, for example, it is not a slow step as shown in FIG. 6 but a sudden step, and in the case of FIGS. Is permitted (step 104). Step 1 above
The downshift permission process when △ Qa> X in 04 can include, for example, issuing a command to that effect, and in this case, responding to the command,
A program (not shown) for shift control by the shift solenoids 5 and 6 is operated by the shift solenoid O so that the corresponding shift speed (first speed in the shift schedule example of FIG. 4) is obtained.
By controlling the combination of N and OFF, downshift (2 →
1 shift).

On the other hand, if the answer to the step 103 is NO, that is, △ Qa ≦ x holds, and therefore the change amount value △ Qa
If the value is equal to or smaller than the threshold value set in advance from the viewpoint described above, the downshift is not performed. That is, in this case, even if the accelerator pedal is depressed, for example, the driver depresses slowly as shown in FIG. 6, and in FIGS. 4 and 5, the driver desires linear acceleration corresponding to the case shown in FIG. Then, in order to match it, in steps 105 and 106, △ Qa ≦
The shift down is prohibited based on the condition of x, and the current position is kept. Therefore, at this time, the above-mentioned △ Qa
Is different from the control in the case where the gear ratio is large, in the shift control program using the shift solenoid, the combination of ON and OFF of the shift solenoid is forcibly maintained at the shift speed (second speed in the example of FIG. 4). Even if the down-shift line corresponds to the down line in the K / D region and crosses it, ΔQa
If ≦ X, downshift (in the case of FIG. 4, 2 → 1
(Shift). The above is the case for a device with a kickdown SW, even when the SW is activated.
If Qa ≦ X, it means that the automatic downshift is not performed and the kick down function is stopped, and that the downshift inhibition by ΔQa ≦ x is prioritized. Thus, smooth acceleration is guaranteed by prohibiting downshifting.

In comparison with the case of FIG. 8 as a comparative example, when the vehicle crosses the downshift line due to depression of the accelerator pedal in the cases of FIGS. The driving force changes as shown by the solid line in (c) (note that in FIG. 3C, the broken lines indicate changes in the engine intake air amount in each case). On the other hand, in the case of FIG. 5 according to this control, in the case (b) described above, the downshift is executed as described above, and as a result, the driving force can be increased by the downshift (see FIG. 5). 5 (b) (solid line (b)), in the above case (a), the driving force changes as shown by the solid line (a) in FIG. 5 (b). That is, to meet the driver's intention, in this case, the driving force can be increased only by the amount of the accelerator, and no downshift is performed. Therefore, the above-described compatibility can be achieved, and even when the driver desires linear acceleration as in the comparative example, a situation in which a large acceleration occurs and gives a sense of strangeness is alleviated.

As described above, in the control of this embodiment, unnecessary downshifts can be prevented in a region where the driver requires linear acceleration. In addition, since the engine intake air change is used, even when compared with the accelerator opening speed, the engine output can be detected more accurately, so that the intention to accelerate is more accurately understood, and control that appropriately reflects this is intended. Can be realized. Further, according to this control, the hunting feeling of the upshift can be prevented immediately. For example, in FIG. 7, in the case where the speed is increased following the 2 → 1 shift down and subsequently the 1 → 2 shift up line is followed by an upshift to the second speed, linear acceleration is desired. In this case, the control is prevented by this control, and such a hunting feeling can be avoided.

Further, in the present control, the downshift is prohibited in the case where the downshift is performed across the down line in the K / D region, despite the desire for linear acceleration, which is accompanied by a shift shock. As a result, while being avoided, there are the following advantages. Regarding the horizontal line in the K / D region as shown in FIG. 7, that is, the horizontal line corresponding to, for example, 7/8 of the throttle opening as described above, the driver is notified when the accelerator pedal is depressed. A check mechanism such as a kick-down SW that operates with a constant depression amount as described above can be provided. However, in such a case, because of the mechanical check, the accelerator opening T
VOs are limited in that they are identical. For example, in the case of four-speed shifting, K / D of 4 → 3, 3 → 2, 2 → 1
The down line in the area is equivalent to the throttle opening 7/8. In such a case, for example, when the kick down SW is mounted on the upper portion of the accelerator pedal, the TVO in the K / D area must be uniform at all shifts. By applying this control, a check mechanism is not required. The K / D area can be freely set (for example, a setting other than 7/8).

The present invention is not limited to the above embodiment. For example, when two or more shift patterns can be obtained for the shift control (e.g., the economy pattern and the power pattern), the discrimination value used to check the change in Qa may be made different. Is not limited to one kind. Also,
Although the description has mainly been given mainly of the case of the 2 → 1 shift, the present invention is not limited to this, and it is needless to say that the present invention is not limited to the prohibition of the downshift in the kick down area. Also,
In the above-described embodiment, the gear position is determined based on the throttle opening and the vehicle speed. However, it is a matter of course that the gear position can be determined based on the intake air amount and the vehicle speed instead of the throttle opening. Furthermore, the present invention can be applied to a gear other than four gears, such as a five gear shift.

[0020]

According to the present invention, it is possible to prohibit a shift to an appropriately low shift speed in a region where the driver requires linear acceleration in the shift control. However, it is possible to alleviate the occurrence of uncomfortable feeling to the driver due to the occurrence of undesired acceleration due to shifting to a low shift speed, thereby ensuring smooth acceleration and determining the engine output state more accurately. It is possible to achieve the above while accurately and accurately reflecting the driver's acceleration intention,
It is also possible to achieve compatibility with acceleration by executing a downshift based on the set shift line characteristics.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a control device of the present invention.

FIG. 2 is a system diagram showing one embodiment of the device of the present invention.

FIG. 3 is a flowchart illustrating an example of a control program executed by the controller of the example.

FIG. 4 is a diagram for explaining the contents of control by the embodiment device, showing an example of a shift characteristic and an example of a shift schedule.

FIG. 5 is an explanatory diagram showing an example of how the throttle opening, the driving force, and the engine intake air amount change.

FIG. 6 is a diagram illustrating an example of a transition of an engine intake air amount near the time of crossing a downshift line.

FIG. 7 is a diagram showing a part of a typical shift point characteristic diagram.

FIGS. 8A to 8C show comparative examples,
6A is a diagram showing the shift schedule, and FIGS. 6B and 6C are diagrams showing the shift schedule in comparison with FIG.

[Explanation of symbols]

 Reference Signs List 1 engine 2 automatic transmission 3 control valve 5, 6 shift solenoid 7 controller 8 throttle sensor 9 vehicle speed sensor 10 engine intake air amount sensor

Claims (1)

(57) [Claims] 1. An automatic transmission for shifting to a predetermined gear position determined by an engine load and a vehicle speed, wherein a detecting means capable of detecting a change amount of an intake air amount of an engine is used, and an output of the detecting means is used. , Depending on engine load and vehicle speed,
A shift control unit including a unit that inhibits shifting to the lower shift speed when the increase change amount of the engine intake air amount when the shift to the shift speed lower than the current shift speed is determined is equal to or less than a predetermined value. A control device for an automatic transmission, comprising: