JPH0324362A - Speed change control device of automatic transmission - Google Patents

Abstract

PURPOSE:To stabilize running performance when a vehicle goes up and down a slope by diagnosing a road grade according to information transmitted from a vehicle speed detecting means, and engine load detecting means, a vehicle speed change detecting means, and a load change detecting means, and controlling speed change according to the result of diagnosis. CONSTITUTION:A grade diagnosing means A diagnoses road grade conditions according to detection information transmitted from both a vehicle speed change detecting means D for detecting the changed condition of vehicle speed, and a load change detecting means E for detecting the changed condition of engine load, in addition to that from a vehicle speed detecting means B and an engine load detecting means C. In accordance with the road grade condition diagnosed, a speed change control means F selects a corresponding speed change pattern from plural speed change patterns set by a speed change pattern setting means G, thereby performing speed change control of an automatic transmission H. Running performance when a vehicle goes up and down a slope is thus stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for controlling the speed change of an automatic transmission, and more particularly to a device that enables speed change control in accordance with road gradient conditions.

BACKGROUND ART Conventionally, vehicles equipped with an automatic transmission equipped with a torque converter are known to shift gears according to a preset shift pattern based on vehicle speed and throttle valve opening. (Refer to Japanese Utility Model Application Publication No. 194231/1983, etc.).

<Problem to be Solved by the Invention> However, the shift pattern is determined based on the vehicle speed V and the engine load represented by the throttle valve opening θ or the basic fuel injection amount T, etc., based on flat road running. Because of this, the speed change control is not performed according to the road gradient,
For example, when driving uphill, the gears are shifted too quickly, resulting in a large drop in output during shifting, making smooth driving impossible, and when driving downhill, the throttle opening is small but the vehicle speed is high, so a high shift position (such as 4th gear) is used. There was a problem that the engine brake was not effective.

The present invention was developed in view of these conventional problems, and detects not only vehicle speed and engine load, but also changes in these conditions to determine the road gradient state, and determines the optimum road gradient according to the gradient state. It is an object of the present invention to provide a speed change control device for an automatic transmission that is capable of performing speed change control.

<Means for Solving the Problem> Therefore, as shown in FIG. 1, the present invention provides a shift control device for an automatic transmission mounted on a vehicle, which includes a vehicle speed detecting means, an engine load detecting means, and a vehicle speed detecting means. A vehicle speed change detection means for detecting a change in vehicle speed, a load change detection means for detecting a change in engine load, a gradient determination means for determining a road gradient state based on detection information from these detection means, and a road gradient state. Shift pattern setting means sets a plurality of different shift patterns according to the speed change pattern, and a corresponding shift pattern is selected from the speed change pattern setting means based on the road gradient state determined by the gradient determination means to control the shift. The system is equipped with a speed change control means. <Operation> In addition to the detection information from the vehicle speed detection means and the engine load detection means, the gradient determination means receives information from the vehicle speed change detection means for detecting changes in vehicle speed and the load change detection means for detecting changes in engine load. The road slope condition is determined based on the detected information.

Based on the gradient state of the road determined in this manner, the shift control means selects a shift pattern according to the gradient state from among the plurality of shift patterns set by the shift pattern setting means and performs shift control. .

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 1 showing the structure of an embodiment, the trans-transition of an automatic transmission 1 consisting of a torque converter and a trans-transition includes a front clutch, a rear clutch, a brake band, a low & reverse brake, and a one-way clutch. In order to control the working oil pressure of each transmission element, solenoid valves 2A to 2E are provided which are interposed in the hydraulic passages leading to these and which control the working oil pressure by controlling the valve duty. On the other hand, a throttle sensor 3 is provided to detect the opening degree of a throttle valve installed in an intake passage of an engine (not shown). Note that the throttle valve opening is a value representative of the engine load, and therefore the throttle sensor 3 constitutes engine load detection means. Further, a vehicle speed sensor 4 as vehicle speed detection means for detecting vehicle speed V is provided near the output shaft of the transmission, and a gear position sensor 5 for detecting gear position G (shift position) is provided in the transmission.

Each signal detected by these is input to the control unit 6.

The control unit 6 is configured with a built-in microcomputer, and based on the signals from each sensor,
A downhill running state is detected, and when a downhill running state is detected, a shift pattern for downhill is selected, a shift point of the transmission is determined based on the shift pattern, and each of the solenoid valves 2A is Shift control is performed by controlling the valve opening duty of ~2E.

FIG. 3 shows the above-mentioned speed change control routine executed by the control unit 5.

In step (denoted as S in the figure) 1, the vehicle speed ■ and the throttle valve opening degree θ are read.

In step 2, the amount of change ΔV in vehicle speed ■ is calculated. The function of step 2 constitutes a vehicle speed change detection means.

In step 3, the rate of change Δθ of the throttle opening θ is calculated. The function of step 3 constitutes a load change detection means.

In step 4, the absolute value IΔ of the amount of change in throttle valve opening is
θ1 is the reference value θ set according to the throttle opening θ
. (See FIG. 4) It is detected whether or not the size is larger than that. Here, where θ is small, the rate of change in the intake air amount Q is large with respect to the change in θ, and the engine torque change is large.
The reference value is set relatively small, and since the change in the intake air itQ due to a change in θ is small where θ is large, the reference value is set relatively large. In other words, the reference value is set to θ in order to judge the slope condition by looking at the change in vehicle speed with respect to the change in engine torque.
It is corrected by the value of . Judgment in step 4 is YES
If S, the process proceeds to step 5, and it is determined whether the amount of change Δθ is a positive value, that is, whether it is during acceleration. If the above judgment is YES, proceed to step 6 and set the vehicle speed change amount ΔV to the positive reference value ΔVO set according to the vehicle speed ■.
(See FIG. 5) It is determined whether the value is the following (including 0 and negative values). Here, the reference value is set smaller as the vehicle speed V increases. That is, the larger the vehicle speed ■, the greater the change ΔV in the vehicle speed V with respect to the engine torque change.
Since it is large, it is corrected by the vehicle speed V.

If the determination in step 6 is YES, it means that the amount of acceleration is small even though the accelerator pedal is depressed greatly, so it is determined that the current driving situation is uphill driving with a large road gradient. Then, the process proceeds to step 7, where a slope-climbing speed change pattern set according to the slope condition is selected from a map stored in the ROM, and speed change control is performed. As shown in the figure, the hill-climbing shift pattern is set to have a characteristic in which the shift point is shifted to a higher vehicle speed side compared to the standard shift pattern for flat roads. Shift control using such a shift pattern for hill climbing provides powerful and stable hill climbing performance.

If the determination in step 6 is No, normal acceleration will be performed according to the accelerator operation, so it will be determined that there is no large uphill slope, and the process will proceed to step 8, where the standard shift pattern for flat roads will be selected. Performs speed change control.

Further, if the determination in step 5 is NO, that is, if the deceleration is performed with the amount of change Δθ in the throttle valve opening θ equal to or greater than a predetermined value, the process proceeds to step 9, where the amount of change ΔV in the vehicle speed V is equal to or equal to the negative reference value. It is determined whether the value is greater than or equal to ΔV0 (meaning in the positive direction, therefore including O and a positive value). This standard value is Δ■. is its absolute value 1-ΔV0 1-Δ■. may be set by searching from the map shown in step 6 above.

If the above determination is YES, the vehicle speed is not increased or decelerated sufficiently in response to a large deceleration operation, so it is determined that the vehicle is traveling downhill with a large slope, and the process proceeds to step 10 to determine the effectiveness of the engine brake. It is determined whether or not the gear has been shifted to a low speed gear position, such as a low gear position.

If the gear shift has not yet been completed, the process proceeds to step 11 and the gear is shifted to the low speed gear position. If the gear has been shifted, the process proceeds to step 12 where the engine brake is maintained at the low or second position below the intermediate vehicle speed. A gear shift pattern for dismounting that maintains a good state of effectiveness (see illustration)
Select to perform gear change control. In addition, the above-mentioned speed change pattern is
The shift point may be set according to the engine speed N, and the shift position may be set so that the engine brake is effectively applied within a range where N is not excessive. For example, even in the high engine speed range N, the engine brake can be applied by setting it to 3rd gear, and in low engine speed ranges, the shift position should be set low enough to suppress engine stalling and maximize engine braking. It is a setting.

In this way, when going downhill with a large slope, the gear is first shifted to the low gear position where engine braking is most effective, and then the gear shift is controlled using a shift pattern that is difficult to shift. Engine braking can be applied as much as possible without being locked into a fixed speed, improving the downhill driving performance of vehicles equipped with automatic transmissions.

If the determination in step 9 is No, that is, if it is determined that there is no large downward slope, the process proceeds to step 8, where the standard shift pattern is selected and shift control is performed.

On the other hand, in step 4, if the absolute value IΔθ1 of the throttle valve opening change amount is less than the reference value, the process proceeds to step 13, where the magnitude of the vehicle speed change amount Δ■ is determined. Mo and Δ
If (2) is greater than or equal to the positive predetermined value Δv1, the process proceeds to step 14, where it is determined whether the current throttle valve opening degree θ is a large value greater than or equal to the predetermined value θ1. And this judgment is Y
In the case of ES, it is determined that the vehicle speed V is increased to a certain extent at the end of the acceleration operation, and the process proceeds to step 8, where the standard shift pattern is selected and shift control is performed. Also, step 14
If the step valve opening θ is a small opening less than the predetermined value θ1, the vehicle speed V is increased even though the engine torque is small. After the determination, the process proceeds to step 10 and subsequent steps to perform the above-mentioned downhill speed change control.

Further, when it is determined in step l3 that the amount of change ΔV in the vehicle speed ■ is less than or equal to the negative predetermined value −ΔV, step l5
It is determined whether the throttle valve opening degree θ is greater than or equal to a predetermined value θ1.

If this determination is YES, the vehicle speed V is decelerated even though the engine torque is sufficiently large, so it is determined that the vehicle is running uphill, and the process proceeds to step 7 according to the uphill shift pattern. Performs speed change control.

If it is determined in step 15 that the throttle valve opening θ is a small opening less than the predetermined value, it is determined that the deceleration is due to engine braking operation, and the process proceeds to step 8, where shift control is performed using a standard shift pattern.

If it is determined in step 13 that the amount of change ΔV in the vehicle speed V is a small value within the predetermined range, the process proceeds to step 8, where shift control is performed using the standard shift pattern. In addition, in order to avoid frequent gear shifts (busy shifts) due to transient changes, each throttle valve opening θ, vehicle speed V, and amount of change ΔV,
Δθ may be set by increasing the sampling period or by using an average value over a predetermined time, or when the same judgment is made more frequently than a predetermined frequency in each judgment of the gradient state, the value of Δθ may be set by increasing the sampling period or by using the average value over a predetermined period of time. It is also possible to perform switching.

In addition, in the above embodiment, steps 4, 5, 69, 1
0, 13, 14. Each of the 15 determination functions constitutes a gradient determination means, and includes standard shift pattern, hill-climbing shift pattern,
The ROM storing the F4 slope shift pattern constitutes a shift pattern setting means, and steps 7, 8, 11.12
Each function and solenoids 2A to 2E control the speed change control means.

FIG. 6 shows each state quantity in a certain running state.

Effects of the Invention> As explained above, according to the present invention, the road slope is determined and the speed change control is performed according to the slope condition.
This stabilizes the driving performance of vehicles equipped with automatic transmissions when climbing or descending hills.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of the present invention, and FIG. 2 is a block diagram showing the structure of the present invention.
FIG. 3 is a flowchart showing the speed change control routine of the embodiment of the present invention; FIG. 4 is a map setting the reference value Δθ0 of the amount of change Δθ used in the above control. , FIG. 5 similarly shows the reference value Δv of the amount of change ΔV.
The map set to 0, FIG. 6, is a time chart showing each state quantity in a certain driving state.

Claims (1)

[Claims] In the shift control device of the automatic transmission installed in the vehicle,
A vehicle speed detection means, an engine load detection means, a vehicle speed change detection means for detecting a change in vehicle speed, a load change detection means for detecting a change in engine load, and a road slope based on the detected information from these detection means. a gradient determining means for determining a road gradient state; a shift pattern setting means for setting a plurality of different shift patterns depending on the road gradient state; and a shift pattern setting means for determining a road gradient state based on the road gradient state determined by the gradient determining means. Shift control means for controlling a shift by selecting a corresponding shift pattern from the above.