JPH02296067A - Automatic transmission control device for vehicle - Google Patents

Abstract

PURPOSE:To control the speed change state at the time of shifting from up-slope running to down-slope running requiring brake operation to be appropriate by holding the specified speed change ratio while the action of a brake device is detected. CONSTITUTION:A control device 20 reads the vehicle speed and throttle opening detected by a speed sensor 2 and a throttle opening sensor 1, calculates the moving average of throttle opening as well as obtains acceleration from the vehicle speed at the specified time, and on the basis of these, calculates the estimated value of running resistance. This estimated value is compared with two reference values LHI, LLOW (LHI>LLOW) for a hysteresis characteristic, and when the estimated value is larger than LHI, up-slope running is judged, and a vehicle is placed in the state of OD inhibition. When the estimated value is smaller than LLOW, a signal from a brake operation detecting means 3 is detected, and when a brake device is not in action, OD inhibition is released, but when the brake device is in action, the release of OD inhibition is not performed. The speed change state at the time of shifting from up-slope running into down-slope running can be thereby made appropriate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission control device for a vehicle, and more particularly, to an automatic transmission control device for a vehicle that determines whether the vehicle is running on an uphill road based on the magnitude of running resistance and changes the transmission characteristics. Concerning improvements to control devices.

(Prior art) Shift control of automatic transmissions used in vehicles, etc. refers to a shift pattern (so-called shift diagram) in accordance with the vehicle speed and throttle opening while the vehicle is running, and determines the gear ratio according to the driving condition. Generally, the gear ratio of an automatic transmission is changed by using the automatic transmission, but the above-mentioned shift pattern is preset assuming typical driving conditions, so if the driving condition is as expected, Although a very satisfactory speed change characteristic can be obtained, the determined speed change ratio may not be appropriate under unexpected driving conditions, such as when driving on an uphill road.

Therefore, the present applicant first proposed a "vehicle automatic transmission control device".
(Japanese Patent Application No. 1-79376) has been filed.

This device determines whether the vehicle is running on an uphill road when the estimated value corresponding to the magnitude of running resistance, which is calculated based on the increase/decrease trend of physical quantities involved in engine combustion and vehicle acceleration, exceeds a reference value. In order to obtain a shift state suitable for running on an uphill road, for example, the shift pattern is switched to a shift pattern for uphill roads, and overdrive is prohibited.

(Problem to be Solved by the Invention) By the way, in the automatic transmission control device for a vehicle according to the prior application, when the driving road surface changes from an uphill road to a downhill road, for example, the speed change state is changed. There was room for improvement in that it no longer matched the driver's feeling.

In other words, in the device according to the prior application, the estimated value of running resistance used for determining uphill running increases when the amount of depression of the throttle pedal is large and the amount of decrease in acceleration of the vehicle is large. The amount is small (
, and a value that decreases when the amount of decrease in vehicle acceleration is no longer that large is used, and when this estimated value becomes smaller than a predetermined value, that is, when the vehicle is no longer running on a hill, overdrive is prohibited, for example. has been released. However, if the overdrive prohibition is canceled when the driving road surface changes from an uphill road to a downhill road, the vehicle will descend down the downhill road while remaining in high gear, resulting in a shift state in which engine braking is not applied when driving downhill. There is room for improvement, as it does not match the driver's feeling.

(Objective of the Invention) Therefore, an object of the present invention is to maintain the gear shift state during uphill road running when the vehicle shifts from uphill road running to downhill road running which requires brake operation.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the automatic transmission control device for a vehicle according to the present invention changes the gear ratio of the automatic transmission when the uphill running is determined by the uphill running determining means. In an automatic transmission control device for a vehicle that changes the gear ratio to a predetermined gear ratio suitable for
a brake operation detection means for detecting operation of the brake device; and at least while operation of the brake device is being detected;
command means for commanding to maintain the predetermined gear ratio;
It is equipped with

(Function) In the present invention, the gear change state when traveling on an uphill road followed by a descending road (a slope road that requires brake operation) is made the same as the gear shifting state when traveling on an uphill road, and the engine brake is When the system is activated, a gear shift state that matches the driver's feeling when driving downhill can be obtained.

(Example) Hereinafter, the present invention will be explained based on the drawings.

1 to 3 are diagrams showing an embodiment of an automatic transmission control device for a vehicle according to the present invention.

First, the configuration will be explained. In FIG. 1, ■ is a throttle opening sensor that detects the throttle opening VTO, 2 is a vehicle speed sensor that detects the vehicle speed V, and 3 is a brake operation detection means. The operation of the device is detected and the brake operation signal S is at (H) level. Output.

10 is an automatic transmission control unit (hereinafter referred to as ATCU),
ATCUIO is internally equipped with a mapped shift pattern. This shift pattern is based on the throttle opening TV
This reference operation determines the gear ratio at that time and outputs the gear shift signal SE.
L is output.

Reference numeral 11 denotes a valve controller of the automatic transmission, and the valve controller 11 combines valves according to SEL and operates the gear ratio of the automatic transmission. Here, the above-mentioned shift pattern is, for example, an overdrive (OD) of 1st to 4th speeds.
) is a shift diagram corresponding to a 4-speed forward automatic transmission,
At a predetermined high vehicle speed or higher, the highest gear (OD) is selected. However, when the OD inhibit signal ODINM is input, OD is not selected.

On the other hand, reference numeral 20 denotes a sub-control device having functions as an uphill road running determination means and a command means; the sub-control device 20
calculates vehicle acceleration α and TVO (moving average value of TVO) according to various signals (V, TVO) from throttle opening sensor 1 and vehicle speed sensor 2, and calculates vehicle acceleration based on these i, τ0. Calculate the estimated resistance value λ, and if λ exceeds a predetermined reference value, OD,
Operates to output □. The sub-control device 20 also detects the (H) level S from the brake operation detection means 3.
When IK is input, if ODINM has already been output, it also operates to continue outputting OD+ and 4H for a predetermined period of time. Inside the sub-control device 20, there are two function tables used when calculating λ, namely f as shown in FIG. 2(a). , function table and Figure 2(b)
It has g+Il+function table shown in FIG. Note that details of these tables will be described later.

Next, the effect will be explained.

FIG. 3 is a flowchart showing part of the processing that is repeatedly executed within the sub-control device 20 at every predetermined calculation cycle. In this flowchart, first, the vehicle speed V detected by the vehicle speed sensor 2 and the throttle opening TVO detected by the throttle opening sensor l are read (steps PI, PZ), and the moving average value TVO of TVO is calculated according to the following formula (step Pi).

・・・・・・■ The above formula ■ is used to smooth out some of the variations and fluctuations in accelerator depression while driving using a filter to improve the reliability of the data, and the time constant of the above formula ■ is 2.
It is preferable to set the time to about 0 seconds.

Next, the first-order difference value Δ■(,
) and use this as the vehicle acceleration. In addition,
If the above ΔV (t) is used as it is in actual calculation processing, there will be large variations, which will hinder the calculation process, so this is smoothed to α (step p,)
.

Then, an estimated running resistance value λ is calculated based on these α and TVO (step ps). The calculation of λ is performed as follows. That is, the function table shown in FIG. 2(a) [. , by TVO, and the function table g(2) shown in FIG. 2(b) by α, and compare both f (X) and g n, looked up from these two tables. The slightly smaller one is determined as λ. In addition, f(. shown in FIG. 2(a) is, for example, 2 points (a) (
It is a linear function straight line connecting (b), and the TVO in (b)
corresponds to the throttle opening normally used on a flat road,
The TVO in (b) corresponds to the throttle opening normally used on steep slopes. In addition, g (8
) is, for example, a linear function straight line connecting two points (c) and (d), where α in (c) corresponds to the acceleration on an uphill road, and α in (d) corresponds to the acceleration on a flat road. Equivalent to. In addition, f(Xl, g
+111 is just an example and is not limited to this.

Here, the concept of calculating λ will be explained. now,
Assume that running resistance is zero (although this is not possible in reality). In this case, as long as even a small amount of engine output torque is generated and the engine output torque is transmitted to the wheels, the vehicle will accelerate. This is because a driving force that exceeds running resistance (zero) is provided. On the other hand, when the running resistance is of a certain magnitude (for example, its value is A), the vehicle continues to run at a constant speed without accelerating or decelerating with a driving force A' equivalent to A. At this time, consider a case where, for example, the road surface changes to an upward slope and the running resistance increases by ΔA. In this case, if the driving force remains A', the vehicle will decelerate, and the acceleration acting on the vehicle at this time will be small (it should be). b
), i) The throttle is opened (TVO is large), and as a result, if the acceleration (1) becomes large, the running resistance (λ) is small.

ii) If the acceleration decreases when the throttle opening is constant, the running resistance is large.

111) If the acceleration remains the same, does not increase much, or decreases regardless of whether the throttle is opened, running resistance is large.

From these representative facts, we have reached the conclusion that there is a correlation between the engine's output torque, which determines the driving force, and the acceleration of the vehicle to which that driving force is applied, which corresponds to the magnitude of the running resistance. can do.

Therefore, the physics of manipulating the output torque of the engine 1
Function table f (xl
By appropriately setting the function table g(.) and the vehicle acceleration (τ) as parameters, and referring to these two tables, the magnitude of the running resistance (estimated value λ for R density) can be calculated. You can know.

The obtained λ is determined by two reference values LHi and LLOw for hysteresis characteristics (L Hi > T-Low
) (step p6, P?).

If λ≧L Hi, ODINM is output and OD is prohibited (step P8), and λ≦L
If it is Low, 5il from the brake operation detection means 3
Check K (step P9), and if S□ is not (H), that is, if the brake device is inactive, cancel the OD prohibition (step P+). On the other hand, 5llK= (H
), that is, if the brake system is operating,
Do not cancel OD prohibition.

Note that the condition for not releasing this is, of course, while the brake device is in operation, but it is preferable to not release it until an appropriate amount of time has passed after the brake device is deactivated. .

As described above, in this embodiment, when the estimated value λ corresponding to the magnitude of the running resistance is larger than Lt+i, uphill running is determined and the OD prohibition state is set. 7, if the brake system is operating, the OD prohibition will not be canceled, so when driving on an uphill road changes to driving on a downhill road that requires brake operation, the OD prohibition will not be canceled. It is possible to maintain the current speed change state until driving downhill, and by applying engine braking when driving downhill, the speed change state can be matched to the feeling of the driver.

(Effects) According to the present invention, the shift state can be made appropriate when the vehicle transitions from running uphill to running downhill, which requires brake operation.

[Brief explanation of drawings]

1 to 3 are diagrams showing an embodiment of the automatic transmission control device for a vehicle according to the present invention, FIG. 1 is a configuration diagram thereof, and FIG.
a) (b) are the function tables f(X), g (11
), and FIG. 3 is a flowchart showing the processing. 3... Brake operation detection means, 20...
- Sub-control device (uphill road travel determination means, command means). Figure 1

Claims (1)

[Scope of Claims] In an automatic transmission control device for a vehicle that changes the gear ratio of an automatic transmission to a predetermined gear ratio suitable for running on an uphill road when the uphill road running is determined by the uphill road running determining means, the braking device comprises: a brake operation detection means for detecting the operation of the brake device, and at least while the operation of the brake device is being detected;
command means for commanding to maintain the predetermined gear ratio;
An automatic transmission control device for a vehicle, characterized by comprising: