JPS6328732A - Method for deciding throttle operation volume in constant-speed running device - Google Patents

Abstract

PURPOSE:To prevent the overshoot of vehicle speed by closing gradually a throttle valve from the point whereat the speed has not yet reached a target value, depending upon the rise of the speed. CONSTITUTION:A throttle control unit 1 has already been inputted with a throttle opening signal (a) on the basis of a position signal for a stepping motor 3 to control the opening of a throttle valve 2, and each type of control signals outputted from a vehicle speed sensor 5 for detecting the speed of the output shaft of a transmission 4, an air flow sensor 6, an intake air temperature sensor 7, an accelerator opening sensor 8, a brake pedal switch 9 and a constant-speed running control switch 10. This switch 10 comprises a main switch 10a, a set switch 10b and a resume switch 10c. By controlling the opening of the throttle valve 2 derivatively, the operation volume thereof is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for determining a throttle operation amount in a constant speed driving device (auto cruise system) of an automobile.

(Prior Art) In conventional constant speed traveling systems, when there is a difference between the set target vehicle speed and the current actual vehicle speed, a step motor or the like is driven and controlled to reduce the vehicle speed difference, and the throttle valve is activated. is opening and closing.

(Problem to be solved by the invention) The throttle valve is opened and closed when there is a difference between the target vehicle speed and the actual vehicle speed. However, it was not compatible with driving conditions such as wind and road slope. Therefore, since the throttle valve is controlled to open and close until the target vehicle speed is reached, there is a problem in that vehicle speed overshoot is likely to occur, and vehicle speed fluctuations occur within a relatively large range around the target vehicle speed.

(Means for Solving the Problems) The present invention adds differential control to the conventional integral control of opening and closing of the throttle valve until the actual vehicle speed reaches the target vehicle speed. This allows for more detailed throttle valve operation, and the current vehicle speed.

The throttle operation amount is controlled by differentially controlling the opening degree of the throttle valve according to the difference between the current speed and the set target vehicle speed, and the amount of change in vehicle speed per unit time in the process of approaching the target vehicle speed (1) above. Characterized by deciding.

(Function) When a difference occurs between the set target vehicle speed and the current vehicle speed, the current vehicle speed, the difference between the set target vehicle speed, and the amount of change in vehicle speed per unit time in the process of approaching this target vehicle speed are Accordingly, the opening degree of the throttle valve is differentially controlled to determine the throttle operation amount. For example, when the target vehicle speed is rapidly approaching, the throttle valve is opened and closed early before reaching the target vehicle speed. On the other hand, if the target vehicle speed is slowly approaching, the throttle valve is opened and closed to reach the target vehicle speed as quickly as possible.
To speed up the convergence of vehicle speed and reduce the width of speed fluctuation.

(Example) Hereinafter, the present invention will be described in detail by taking as an example a constant speed traveling device suitable for carrying out the method invention.

In FIG. 1, a throttle control unit 1 consisting of a computer has a throttle opening signal a based on a position signal of a stepping motor 3 that controls the opening of a throttle valve 2, and a vehicle speed that detects the rotational speed of an output shaft of a transmission 4. Vehicle speed signal from sensor 5, intake pressure signal from air flow sensor 6, intake air temperature signal from intake air temperature sensor 7, accelerator opening signal from accelerator opening sensor 8 that detects the amount of depression of the accelerator pedal, and brake pedal ON from brake pedal switch 9. Various control signals outputted by the signal and constant speed running control switch 10 are input. The constant speed driving control switch 1O is a main switch 10a that turns the system on and off, a set switch 10b that sets the current vehicle speed as the target vehicle speed, and a function that restores the constant speed driving mode that was canceled by pressing the brake pedal or accelerator pedal. and a resume switch 10c.

For example, if you want to drive at a constant speed of 1100 km/h, turn on the main switch 10a to start up the system, then press the set switch 10b, and the throttle control unit 1 will receive various signals. is calculated, a target throttle opening is set, and the stepping motor 3 is driven to maintain the vehicle speed at the set value. That is, if there is a difference between the set target vehicle speed of 1100 k/h and the current actual vehicle speed, the control unit 1 sets the target throttle opening, outputs a throttle opening signal to the stepping motor 3, and drives the stepping motor 3. The amount of intake air is controlled by opening and closing the throttle valve 2.

The present invention is characterized by a method for determining the amount of operation of the throttle valve 2. This will be explained in detail based on FIG. Note that since the operation of the constant speed traveling device is already well known, the differential control routine will be explained.

In step al, the current vehicle speed Vn and the previous vehicle speed V
A vehicle speed change VCNG is calculated from the difference with n-1. In step a2, it is determined whether the vehicle speed change VCNG is "0" or not. If it is not "O", that is, if the vehicle speed has changed, the process proceeds to step a3, where the current time Tn and the previous vehicle speed Vn-1 are determined. The difference from the time Tp when VCNG is reached is calculated to calculate the required vehicle speed change time TIME, which is the time required for the vehicle speed change VCNG. Time required for this vehicle speed change TI
Even if the same vehicle speed difference value is calculated, ME changes in length depending on the slope of the road and the direction of the wind.

Next, in step a4, the current time Tn is changed to the previous time Tp.
Replace with In step a5, the vehicle speed difference DEFV is calculated from the difference between the current vehicle speed Vn and the target vehicle speed Vt, and then in step a6 it is determined whether the vehicle speed difference DEFV is rOJ. If it is not "O", that is, if the vehicle speed is changing, it is determined in step d7 whether the vehicle speed change VCNG is positive (accelerating) or negative (decelerating). Vehicle speed change VCNG
If the vehicle speed difference DEF■ is under positive acceleration, the process proceeds to step a8, and it is determined whether the vehicle speed difference DEF■ is positive or negative. If the vehicle speed difference DE FV is positive, the current vehicle speed is greater than the target vehicle speed.
The vehicle speed is increasing beyond the target vehicle speed (overshoot) (see ■ in Figure 4). If the vehicle speed difference DEFV is negative, it means that the current vehicle speed is smaller than the sixth vehicle speed, and the vehicle speed is increasing toward the target vehicle speed (see ■ in FIG. 4). If the result in step a8 is positive, the process proceeds to the first correction determination process DCAL1 in step a9, and if it is negative, the process proceeds to the second correction determination process DCAL2 in step alo.

In step a7, if the vehicle speed change VCNG is negative and deceleration is in progress, it is determined in step all whether the vehicle speed difference DEFV is positive or negative. If the vehicle speed difference DE FV is negative, it means that the current vehicle speed is smaller than the target vehicle speed, and the vehicle speed exceeds the target vehicle speed and is falling (undershoot) (see ■ in FIG. 4). If the vehicle speed difference DEFV is positive, it means that the current vehicle speed is greater than the target vehicle speed, and the vehicle speed is decreasing toward the target vehicle speed (see ■ in Figure 4).
If it is negative, the third correction determination process DC of step a12
The process proceeds to AL3, and if positive, the process proceeds to step a13, the fourth correction determination process DCAL4.

Here, the subroutine of the correction determination process is shown in FIG.
I will explain. The throttle control unit 1 stores the current vehicle speed Vn and the vehicle speed difference DE, which is the difference between the current vehicle speed and the target vehicle speed, for each of the first to fourth correction determination processes DCAL1 to DCAL4.
FV, vehicle speed change time required as parameter 3
A dimensional map is provided. First correction determination process DCA
As shown in Figure 4 ■, the LI three-dimensional map shows the amount of correction Δ0□(
≦0). Second correction determination process DCA
The three-dimensional map of L2 is as shown by the broken line ■ in Figure 4.
If the gradient of the speed change per unit time of the vehicle speed approaching the target vehicle speed (increasing) is large, the throttle valve is closed, and if the gradient is small, as shown by the solid line ■, the correction amount Δθ2 is determined to open the throttle valve. It's a map.

The three-dimensional map of the third correction determination process DCAL3 shows the vehicle speed (
This is a map for determining the correction amount Δθ3 (≧0) for opening the throttle valve in order to return the vehicle speed (during deceleration) to the target vehicle speed. The three-dimensional map of the fourth correction determination process DCAL 4 shows that the slope of the speed change per unit time of the vehicle speed approaching the target vehicle speed (during deceleration) is large as shown by the broken line ■ in FIG. This is a map for determining the correction amount Δθ4 for opening the throttle valve and closing the throttle valve if the gradient is small, as shown by the solid line 2 in FIG. Then, in step a7 and step a8 (or step all), when one correction determination process is selected from among the four correction determination processes, the optimum correction amount is determined from the three-dimensional map possessed by that correction determination process. is searched.

Returning to FIG. 2, in step a9, the first correction determination process DCALL searches for the correction amount Δθ, and in step a14, ○ is added to the correction amount to the current throttle opening ON to set a new target throttle opening. Determine the degree Ot. When the target throttle opening is determined to be 0, the throttle control unit 1 (see Figure 1) outputs a target throttle opening signal to the stepping motor 3 to drive it and operate the throttle valve 2 in the direction of closing. let After the correction amount ΔO0 is cleared in step a15, the current vehicle speed Vn is replaced with the previous vehicle speed Vn-1 in step a16, and the process returns.

In step alO, the second correction determination process DCAL2
When the controller searches for the correction amount Δ02, in step all, the correction amount Δθ2 is added to the current throttle opening On to set a new target throttle opening Ot. When the target throttle opening degree Ot is determined, the throttle control unit 1 outputs a target throttle opening signal S to the stepping motor 3 to drive it, and the throttle valve 2
Open and close. At this time, as shown by the broken line ■ in Figure 4,
If the vehicle speed increases per unit time quickly, the target vehicle speed Vt will be reached in a short time, so the throttle valve is closed early to prevent overshoot.

On the other hand, as shown by the solid line ■ in Figure 4, if the rate of increase in vehicle speed per unit time is slow, it will take a long time to reach the target vehicle speed, so taking into account the delay time of the fuel supply system,
Furthermore, the throttle valve is opened to shorten the time it takes to reach the target vehicle speed. After the correction amount Δ02 is cleared in step a18, the current vehicle speed Vn is replaced with the previous vehicle speed Vn-1 in step a16, and the process returns.

In step a12, the third correction determination process DCAL3
When the controller searches for the correction amount ΔO1, in step a19, the correction amount Δθ is added to the current throttle opening θn to set a new target throttle opening θt. When the target throttle opening θ is determined, the throttle control unit 1 outputs a target throttle opening signal S to the stepping motor 3 to drive it, and the throttle valve 2
open. As a result, the vehicle speed, which had been moving away from the target vehicle speed as shown by the solid line ■ in Figure 4, will now change to the target vehicle speed ■
Then, after clearing the correction amount ΔO1 in step a20, the current vehicle JVn is replaced with the previous vehicle speed Vn-1 in step a16, and the process returns.

In step a13, the fourth correction determination process DCAL4
When the controller searches for the correction amount Δ04, in step a21, the correction amount Δ04 is added to the current throttle opening On to set a new target throttle opening θt. When the target throttle opening degree Ot is determined, the throttle control unit 1 outputs the target throttle opening degree a9fl) to the stepping motor 3 and drives it by 1, thereby opening and closing the throttle valve 2. At this time, as shown by the broken line ■ in Figure 4, if the vehicle speed decreases per unit time quickly, the target vehicle speed will be reached in a short time, so in preparation for undershoot, allow for a delay time in the fuel supply system in advance. , and open the throttle valve early. On the other hand, as shown by the solid line ■ in Figure 4, if the rate of decline in vehicle speed per unit time is slow, it will take a long time to reach the target vehicle speed, so it will take more time to reach the target vehicle speed by closing the throttle valve. Shorten.

After the correction amount Δθ is cleared in step a22, the current vehicle speed Vn is replaced with the previous vehicle speed Vn-1 in step a16, and the process returns.

Which of the first to fourth correction determination processes 1 to 4 is to be performed is divided into two depending on whether the vehicle speed change VCNG in step a7 is accelerating or decelerating. This is determined by determining whether the vehicle speed is above or below the vehicle speed (see Figure 4) and determining whether the current vehicle speed in step all is above or below the target vehicle speed (see Figure 4). .

Then, by repeating the differential correction routine shown in FIG. 2, the throttle valve 2 is opened and closed by determining its operation amount before the current vehicle speed Vn reaches the target vehicle speed Vt, while keeping in mind the time required for the change in vehicle speed. This means that
The vehicle speed only changes slightly along the target vehicle speed.

In other words, each time the vehicle speed changes by a unit amount, for example, 1 kn/h, by measuring the time required for that change, the environment in which the vehicle is located (disturbances such as wind and road slope) is estimated, and detailed calculations are made. Determines the amount of throttle valve operation.

(Effects of the Invention) As described above, according to the method for determining the throttle operation amount of the present invention which includes differential control, the vehicle speed changes from the time when the vehicle speed has not reached [1 target vehicle speed] according to the rate of increase (decrease) of the vehicle speed. By gradually closing (opening) the throttle valve, overshoot (undershoot) of vehicle speed can be suppressed. In addition, even if there is an overshoot (undershoot) due to the slope of the road or a tailwind, the amount of throttle valve operation is determined according to the vehicle speed, the difference from the target vehicle speed, and the time required to change the vehicle speed, so the current vehicle speed will reach the target vehicle speed. The convergence speed is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of a constant speed traveling device to which the present invention is applied, FIG. 2 is a flowchart showing a differential control routine that is executed by interrupting constant speed traveling control, and FIG. 3 is a diagram shown in FIG. FIG. 4 is a flowchart showing a subroutine of the correction determination process, and FIG. 4 is a diagram for explaining the positional relationship of the current vehicle speed with respect to the target vehicle speed. 1...Throttle control uni-so 1-12...
Throttle valve, 3...Stepping motor, Vn
...Current vehicle speed, Vt...Target vehicle speed, DEFV...
Vehicle speed difference, VCNG...Vehicle speed change, TIM E...
・! tL speed change required time, Δθ, ~Δθ4...correction amount. Place 1 Inoue 4 Z

Claims (1)

[Claims] When there is a difference between the set target vehicle speed and the actual vehicle speed, in a constant speed driving system that opens and closes the throttle valve in a direction that brings the actual vehicle speed closer to the target vehicle speed, the current vehicle speed, the current vehicle speed, and the set target vehicle speed are A method for determining a throttle operation amount, characterized in that the throttle operation amount is determined by differentially controlling the opening degree of the throttle valve according to the difference between the vehicle speed and the amount of change in vehicle speed per unit time in the process of approaching the target vehicle speed.