JP2002192927A - Air suspension control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of automatic control to a target vehicle height via control of air supply and discharge to and from air suspensions, wherein a conventional air suspension control method involves individual control on each air suspension at the same time to cause all control on one air suspension to end in a countervailed control effect influenced by control on another air suspension, and air to be consumed wastefully. SOLUTION: For automatic control to a target vehicle height, priority sequence is given to control modes, wherein control with air discharge is first executed for every vehicle height on each axle (steps 1 to 4: rear-axle air discharge control, steps 6 to 9: front-axle air discharge control), before control with air supply is executed (steps 11 to 14: rear-axle air supply control, steps 16 to 19: front-axle air supply control). Between the controls for every vehicle height on each axle, a given time is ensured long enough for the preceding control result to become stable. Wasteful consumption of air is reduced, and trouble about the control is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air suspension control method for a vehicle using an air suspension as a vehicle body frame suspension, and more particularly to an automatic control for controlling a target vehicle height such as a reference vehicle height. .

[0002]

2. Description of the Related Art An air suspension uses an air spring as a chassis spring of a vehicle, and is mainly used for large trucks and the like. In a truck or the like, it is desired from the viewpoint of safe driving and efficient driving that the height of the body frame (vehicle height) be maintained at a predetermined height from the axle regardless of the magnitude of the loaded load. The predetermined height is said to be the "reference vehicle height",
The value is appropriately determined depending on the vehicle type. In a vehicle using an air spring, when the vehicle height changes, air is supplied from an air tank or air is discharged from the air spring to the atmosphere (exhaust) in order to return to the reference vehicle height.
"Air control" is automatically performed.

[0003] In addition to automatic control to a reference vehicle height, when loading and unloading luggage, etc., the vehicle height is controlled to a desired height. FIG. 5 is a diagram illustrating the vehicle height control during the loading / unloading operation. In FIG. 5, 1 is a vehicle, 2
Is a front wheel, 3 is a rear wheel, 4 is an onboard controller, 32 is luggage, and 33 is a platform. FIG. 5A shows that, when the height of the rear part of the bed of the vehicle 1 is lower than the height of the platform 33 for loading and unloading the load 32, the air is supplied to the air spring (not shown) of the rear wheel 3, Is raised to match the height of the platform 33 (the dotted line indicates the raised state).

FIG. 5 (2) shows that, in order to facilitate the work of lowering the load 32, air is supplied to an air spring (not shown) of the front wheel 2 to slightly raise the front part of the cargo bed, This shows a case in which the slope is gradually inclined toward the center (a dotted line indicates a state where it is raised). FIG.
(3) shows a state in which the air suspension is controlled prior to the start of traveling after the luggage 32 has been loaded, and the air suspension is returned to the reference vehicle height.

In order to control the height to a desired height in this way,
This is also performed by a remote control device from outside the vehicle 1. FIG.
FIG. 3 is a diagram showing a vertical arrangement state of an air suspension control device including such a remote control device. In FIG. 2, 1 is a vehicle, 3A and 3B are rear wheels, 4 is an onboard controller, 7A and 7B are rear shafts, 8A and 8B are air springs, 9 is a differential device, 30 is a vehicle height manual adjustment device, and 31 is Connection cable.

An air spring 8A is provided on a rear shaft 7A between the differential device 9 and the rear wheel 3A, and an air spring 8B is provided on a rear shaft 7B between the differential device 9 and the rear wheel 3B. is set up. Here, only the rear wheel part is shown,
A similar air spring is installed on the front wheel.
The vehicle height manual adjustment device 30 is connected to the vehicle-mounted controller 4 of the vehicle 1 via a connection cable 31. When a command for raising or lowering is issued from the vehicle height manual adjustment device 30, air is supplied to or discharged from the air spring at the specified location.

FIG. 4 is a diagram showing a planar arrangement of the air suspension control device. Reference numerals correspond to those in FIG. 2, 2A and 2B are front wheels, 3A and 3B are rear wheels, 5A and 5B.
Is a front shaft, 6A and 6B are air springs, 10 is an air pipe, 11 is a vehicle height sensor, 12 is an air distribution unit, 13 is an electromagnetic valve, 13E is an atmosphere opening port, 14 is an air tank, 15
A and 15B are electromagnetic valves, 15AE and 15BE are air opening ports, and 16 and 17 are vehicle height sensors.

When the electromagnetic valve is opened, the air tank 14
Is supplied to the air spring, and the supply is stopped when the air spring is closed. When the air opening of the electromagnetic valve is opened, the air of the air spring is discharged to the atmosphere. The supply of air to the air springs 6A and 6B of the front shaft is performed through a route from the air tank 14 → the electromagnetic valve 13 → the air distribution unit 12. Air distribution unit 12 → solenoid valve 13
(The supply and discharge of air are not performed individually by the air springs 6A and 6B, but are performed in common.)

The supply of air to the air spring 8A of the rear wheel is performed through a path from the air tank 14 to the electromagnetic valve 15A, and the air is discharged from the air opening port 15AE, and the air spring 8A is opened to the air from the electromagnetic valve 15A. Mouth 15AE
It is performed by the route. The supply and discharge of air to and from the air spring 8A of the rear wheel are performed in the same manner. Therefore, the supply and discharge of air to and from the air springs 8A and 8B can be controlled individually by individually controlling the electromagnetic valves 15A and 15B (for example, the liquid discharge port of the tank lorry is installed at the rear right side). In such a case, it can be controlled so that the rear right becomes lowest to make it easier for the liquid to flow.)

The control of each electromagnetic valve is performed by a control signal from the on-board controller 4. In generating the control signal, the on-vehicle controller 4 refers to detection signals from the vehicle height sensor 11 installed on the front shaft and vehicle height sensors 16 and 17 installed on the rear shaft. For example, when performing automatic return control to the reference vehicle height, air is supplied or discharged so that the detection signal from each vehicle height sensor becomes the reference vehicle height.

FIG. 3 is a diagram showing an example of the vehicle height manual adjustment device 30. As shown in FIG. The reference numerals correspond to those in FIG. 2, 20 is a display window, 21 is a display lamp, 22 is a front axle-side vehicle height adjustment switch, 23 is a rear axle-side vehicle height adjustment switch, 24 is a vehicle height return switch, and 25 and 26. Is a memory switch, 27 is an up switch, 28 is a down switch, and 29 is an emergency stop switch. Although not shown, the vehicle height manual adjustment device 30
Has a built-in controller configured as a computer including a storage element and a CPU. Indicator lamp 2
Reference numeral 1 indicates that a predetermined switch (for example, the front axle-side vehicle height adjustment switch 22 or the rear axle-side vehicle height adjustment switch 23) is turned on. The front axle height adjustment switch 22 is a switch that is turned on when the vehicle height on the front axle (the front wheel axle) side is to be controlled.
The rear axle vehicle height adjustment switch 23 is a switch that is turned on when the vehicle height on the rear axle (rear wheel axle) side is to be controlled.

The vehicle height return switch 24 is a switch that is turned on when the manual control to the desired height is completed and the vehicle automatically returns to the reference vehicle height. The emergency stop switch 29 is a switch that is turned on when the operation being performed at that time is stopped during manual control to a desired height. Lift switch 2
Reference numeral 7 denotes a switch that is turned on when the vehicle height is to be increased. While continuing to turn on, air is supplied to the designated air spring. The lowering switch 28 is a switch that is turned on when lowering the vehicle height. While continuing to turn on, air is discharged from the designated air spring. These vehicle height controls are performed via the on-board controller 4. The memory switches 25 and 26 are switches that are turned on when storing the height or the like of a frequently used specific platform.

After the vehicle height is intentionally adjusted to a desired height by operating the vehicle height manual adjustment device 30, automatic return to the reference vehicle height is completed if loading and unloading of luggage is completed. Control is performed. The control is started by turning on the vehicle height return switch 24 and sending a command to the vehicle controller 4.

[0014]

[Problems to be Solved by the Invention] (Problems) In a case where automatic control is performed so as to achieve a target vehicle height, the conventional air suspension control method wastes the control that has been performed and reduces the air more than necessary. There was a problem of consuming a lot.

(Explanation of Problems) In the conventional air suspension control method, the air springs are simultaneously and simultaneously controlled based on a detection signal from a vehicle height sensor installed near each air spring. For example, if the vehicle height is different from the reference vehicle height for loading and unloading work, and you want to control to automatically return to the reference vehicle height after completing the work, The supply and discharge of air are individually and simultaneously performed. However, an increase (or a decrease) in the vehicle height of that portion due to a certain air spring affects the vehicle height of another portion. For example, when the vehicle height on the front shaft side is reduced by discharging air from the air springs 6A and 6B on the front shaft, the center of gravity moves to the lower side, so that the load on the rear shaft side is smaller than before. . Then, under the influence, the vehicle height on the rear axle side is increased by that amount (without supplying air to the air springs 8A and 8B on the rear axle side).

On the other hand, the rear shaft side air springs 8A, 8B
Are controlled based on the vehicle height detected before being affected. For example, when the detected value is lower than the reference vehicle height, air is supplied. However, in that case, the supply of air is performed more than necessary. This is because although the vehicle height is increased due to the influence of the front axle, the ascent control is performed without considering the height. Therefore, after this, control for lowering the excessively high value must be performed again later. As a result, the previously performed control becomes useless, and the useless control is repeated, so that more air is consumed than necessary. An object of the present invention is to solve the above problems.

[0017]

In order to solve the above problems, the present invention provides a method for supplying air to an air suspension,
In the air suspension control method for controlling the vehicle height by controlling the discharge, the descending control by discharging the air is performed first for each vehicle height on each axle, and then the rising control is performed by supplying the air for each vehicle height on each axle. , And a predetermined period of time long enough to stabilize the result of the immediately preceding control is taken between the above-described controls on the vehicle height at each axle. Further, the above-described lowering control may be performed in the order of the rear-axis lowering control and the front-axis lowering control, and the above-described raising control may be performed in the order of the rear-axis raising control and the front-axis raising control.

(Outline of Operation to be Solved) When automatically controlling to a target vehicle height, a descending control by discharging air is performed first, and then a rising control by supplying air is performed while being mixed. Therefore, wasteful consumption of air is reduced, and control effort is also reduced. When the descending control and the ascending control are completed for the vehicle height at each axle, a predetermined period of time long enough to stabilize the result of the control performed immediately before the next control is performed. Therefore, the control is not repeated needlessly.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following four types of air suspension control modes are available. Front axis up control Front axis down control Rear axis up control Rear axis down control

In the present invention, in order to minimize the consumption of the air stored in the air tank 14, the control for discharging the air is performed first, and the control for supplying the air is performed later.
That is, the following priorities are assigned to the control modes (however, the order may be reversed or the order may be reversed). Rear-axis lowering control Front-axis lowering control Rear-axis raising control Front-axis raising control In addition, in order to minimize waste of control, after performing control in one control mode, the result of that control stabilizes. After a while, the control mode is shifted to the next control mode.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart illustrating the air suspension control method of the present invention. Here, the control for automatically returning to the reference vehicle height is described above.
, And will be described as an example. It should be noted that there are the following merits when performed in this order. The effect on the loaded luggage is greater on the rear axle, but by controlling the axle first, the effect on the luggage can be reduced. In addition, although the load change due to air control is larger on the rear shaft, the controllability of the control can be improved by controlling the rear shaft with the larger load change first.

Step 1: A vehicle height on the rear axle side is detected. This is performed by the vehicle height sensors 16 and 17. Step 2: Compare with the reference vehicle height. The reference vehicle height is stored in the on-board controller 4 in advance, and is compared with this. Step 3: If the detected vehicle height is higher than the reference vehicle height,
Lower the vehicle height on the rear axle side. That is, the electromagnetic valves 15A,
A control signal is sent to 15B to release air from the air springs 8A and 8B. Then, the process returns to step 1 and the control is repeated.

Step 4: If the vehicle height is not higher than the reference vehicle height in Step 2, the control for lowering the vehicle height on the rear axle side is stopped. Step 5: Wait for a predetermined time t to elapse. this is,
When the lowering of the rear axle-side vehicle height is controlled, the movement of the center of gravity also affects the front axle-side vehicle height, but this is because it is necessary to wait for the result of such an effect to stabilize (for example, because the rear axle side is lowered). In some cases, the vehicle may swing back and forth, but wait until it stabilizes.) The length of the predetermined time t is set to be long enough to stabilize the result of the control.

Step 6: The vehicle height sensor 11 detects the vehicle height on the front shaft side. Step 7: Compare with the reference vehicle height. Step 8: If the vehicle height on the front axle side is higher than the reference vehicle height, a control signal is sent to the electromagnetic valve 13 so as to open the air opening 13E, and the air from the air springs 6A and 6B is discharged. Lower the height. Step 9: If the comparison in Step 7 shows that the vehicle height is not higher than the reference vehicle height, the lowering of the front axle side vehicle height is stopped. Step 10: Wait for a predetermined time t to elapse. This is the same as step 5.

Step 11: The vehicle height on the rear axle side is detected.
The air springs 8A and 8B can control the left and right vehicle heights on the rear axle to different heights. However, when returning to the reference vehicle height, the right and left sides are controlled to the same height. Step 12: The detected vehicle height is compared with a reference vehicle height.
If it is higher, the process returns to step 3 and the air springs 8A, 8A
The air of B is discharged and lowered. Step 13: When the vehicle height is lower than the reference vehicle height, air is supplied to the air springs 8A and 8B to increase the rear shaft side vehicle height. Step 14: When the vehicle height is equal to the reference vehicle height, the rear axle vehicle height is stopped from rising. Step 15: Wait for a predetermined time t to elapse.

Step 16: The vehicle height on the front axle side is detected. Step 17: The detected front axle-side vehicle height is compared with the reference vehicle height. If the vehicle height is higher than the reference vehicle height, the process proceeds to step 8 and is lowered (air discharge). Step 18: If the vehicle height is lower than the reference vehicle height, the front shaft-side vehicle height is increased (air supply). Step 19: When the vehicle height is equal to the reference vehicle height, the elevation of the front axle side vehicle height is stopped. As a result, both the rear axle-side vehicle height and the front axle-side vehicle height are set to the reference vehicle height.

In the above example, control for automatically returning to the reference vehicle height has been described as an example. However, when a height different from the reference vehicle height is given as a target value and the height is automatically controlled. Is performed in a similar manner.

[0028]

As described above, according to the air suspension control method of the present invention, the following effects can be obtained. (Effects of the Invention of Claim 1) When automatically controlling to a target vehicle height, control modes are prioritized, lowering control by discharging air is performed first, and then rising control by supplying air is mixed. This is performed while the air is being wasted, so that wasteful consumption of air is reduced and the trouble of control is also reduced.

(Effect of the Second Invention) If the descending control is performed in the order of the rear axle lowering control and the front axle lowering control, and the ascending control is performed in the order of the rear axle ascending control and the front axle ascending control, the effect described in the preceding paragraph is obtained. In addition to the above, it is possible to reduce the influence of the air control on the loaded luggage and to improve the followability of the air control.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an air suspension control method according to the present invention.

FIG. 2 is a diagram showing a vertical arrangement of an air suspension control device.

FIG. 3 shows an example of a vehicle height manual adjustment device.

FIG. 4 is a diagram showing a planar arrangement of the air suspension control device.

FIG. 5 is a view for explaining vehicle height control during loading / unloading work.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2A, 2B ... Front wheel, 3A, 3B ... Rear wheel, 4 ...
In-vehicle controller, 5A, 5B: front shaft, 6A, 6B: air spring, 7A, 7B: rear shaft, 8A, 8B: air spring, 9: differential device, 10: air pipe, 11: vehicle height sensor, 12: air Distributing part 13 Electromagnetic valve 13
E: air release port, 14: air tank, 15A, 15B ...
Electromagnetic valve, 15AE, 15BE ... air opening port, 16,
17: vehicle height sensor, 20: display window, 21: display lamp,
22: front axle side vehicle height adjustment switch, 23: rear axle side vehicle height adjustment switch, 24: vehicle height return switch, 25, 26 ... memory switch, 27 ... up switch, 28 ... down switch, 29 ... emergency stop switch, 30 ... manual height adjustment device, 31 ... connection cable, 32 ... luggage, 33 ... platform

Claims (2)

[Claims] In an air suspension control method for controlling a vehicle height by controlling supply and discharge of air to an air suspension, descending control by discharging air is performed first for each vehicle height on each axle, and thereafter, Ascending control by air supply is performed sequentially for each vehicle height at each axle while mixing, and during the above-described control for vehicle height at each axle, the result of the immediately preceding control is sufficiently stabilized. An air suspension control method characterized by taking a predetermined length of time. 2. The air according to claim 1, wherein the lowering control is performed in the order of rear shaft lowering control and the front shaft lowering control, and the raising control is performed in the order of rear shaft raising control and front shaft raising control. Suspension control method.