JPH0637122B2 - Air suspension controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an air supply between the main chamber and the sub chamber, the spring constant of which changes depending on whether or not air is communicated or cut off. The present invention relates to an air suspension control device that changes a vehicle height according to exhaust gas.

[Prior Art] An air suspension control device of this type adjusts a spring constant by connecting and disconnecting a main chamber and a sub chamber of the air suspension according to a running state of a vehicle and adjusting the spring constant of the air suspension. The vehicle height is adjusted by supplying and exhausting air to the main room.

Conventionally, such an air suspension control device always adjusts the spring constant over the latter, because the former adjustment of the spring constant has an effect on the transient response when the vehicle is running. I was letting it. In other words, when the adjustment timings of the two overlap, the former adjustment of the spring constant always takes precedence over the latter vehicle height adjustment.

[Problems to be Solved by the Invention] As described above, the conventional control device always prioritizes the adjustment of the spring constant of the air suspension over the vehicle height adjustment. First, the spring constant is adjusted to a large value, and then the vehicle height is adjusted only after the vehicle reaches a predetermined speed. Therefore, the vehicle height is not adjusted due to the load variation in the transient state when the vehicle starts.

However, if the internal air leaks due to replacement of the air suspension due to market service or non-use for a long period of time, the following problems occur when the vehicle starts.
In other words, when the vehicle starts, despite the low air pressure in the air suspension, that is, the vehicle height is extremely low, the main chamber and sub chamber of the air suspension are shut off to increase the spring constant. However, there is a problem that the suspension function is impaired due to insufficient air pressure.

The present invention solves such a problem.

[Means for Solving the Problems] In the air suspension control device of the present invention, the spring constant is changed in accordance with the communication and interruption of air between the main chamber and the sub chamber, and the air to the main chamber is changed. Based on the air suspension that changes the vehicle height according to supply and exhaust, the running state sensor that detects the running state of the vehicle, the vehicle height sensor that detects the vehicle height, and the detection signal from the vehicle height sensor. And a controller that adjusts the vehicle height by controlling the air suspension, and has priority over this vehicle height adjustment and that adjusts the spring constant of the air suspension according to the running state of the vehicle detected by the running state sensor. In the air suspension control device, when the vehicle height detected by the vehicle height sensor is equal to or lower than a predetermined height, the controller is irrespective of the traveling state. In preference to adjusting values constant, and characterized in that to increase the vehicle height by controlling the air suspension to a predetermined height.

[Operation] When the vehicle height is lower than a predetermined value and extremely low, the air suspension control device of the present invention gives priority to the vehicle height adjustment over the adjustment of the spring constant of the air suspension, and immediately sets the vehicle height to the predetermined value. If the vehicle height is higher than a predetermined value, the spring constant of the air suspension is adjusted prior to the vehicle height adjustment, as before.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 designates a total of four air suspensions. The left and right upper suspensions in the figure are provided on the left and right of the front of the vehicle, and the left and right lower suspensions in the figure are provided on the left and right of the rear of the vehicle. Since these four air suspensions 1 have the same configuration, the right side of the front will be described below as a representative.

The main body 2 of the air suspension 1 is attached to the vehicle side and the axle side at its upper and lower ends.
A main chamber 4 is formed in the portion of the air shock absorber 3. The main chamber 4 is connected to the sub chamber 5, and an actuator 5 connects or disconnects them between them. Such an air suspension 1
The spring constant is increased by disconnecting the main chamber 4 and the sub chamber 5 by the actuator 6. In addition, the vehicle height is increased by supplying air to the main chamber 4 and the sub chamber 5,
The vehicle height is lowered by exhausting air from the main chamber 4 and the sub chamber 5.

The control device of the present example targets such an air suspension 1.

A vehicle height sensor 7 is provided between the vehicle body A side and the axle B side on the front right side of the vehicle so as to correspond to the air suspension 1 on the front right side. The vehicle height on the right side of the front of the vehicle is detected. The vehicle height sensor 7 is also provided on the left side of the front of the vehicle and the left and right sides of the rear so as to correspond to each of the other three air suspensions 1. A compressor 8 for supplying pressurized air is connected to the main chamber 4 and the sub chamber 5 of the air shock absorber 2, and an exhaust solenoid valve 9 and a supply / exhaust solenoid valve 10 are provided in the connection path. ing. Reference numeral 11 denotes a running state sensor that detects the running state of the vehicle. In the case of this example, a vehicle speed sensor 12 that detects the running speed of the vehicle,
A steering angle sensor 13 for detecting the operation angle of the steering wheel and a brake lamp switch 14 are used. The detection signals of the traveling state sensor 11 and the vehicle height sensor 7 are input to the controller 15, and the controller 15 receives the actuator 6, the compressor 8, the exhaust solenoid valve 9, and the supply of the air suspension 1 based on the detection signals. The exhaust solenoid valve 10 is controlled.

Next, the operation will be described.

The controller 15 adjusts the vehicle height and the air suspension 1
Adjust the spring constant of.

First, the vehicle height adjustment will be described.

The vehicle height sensor 7 indicates that the vehicle height is “low”, “neutral”, or “high”.
And three stages are detected. When the vehicle height sensor 7 generates a "low" signal, the vehicle height sensor 7 gives an operation signal to the compressor 8 and the air supply / exhaust solenoid valve 10, and the compressor 8 causes the inside of the main chamber 3 and the sub chamber 5 of the air suspension 1 to travel. Supply air to the vehicle to raise the vehicle height. When the vehicle height sensor 7 generates a signal "high", the controller 1
5 gives operation signals to the exhaust solenoid valve 9 and the supply / exhaust solenoid valve 10, and the main chamber 3 of the air suspension 1
The air in the sub chamber 5 is exhausted to lower the vehicle height. In this way, the controller 15 controls the vehicle height sensor 7 to be “low”,
The vehicle height is automatically adjusted to a predetermined value by using the signal "high" as a vehicle height adjustment request signal.

On the other hand, the adjustment of the spring constant of the air suspension 1 is performed under the condition that the vehicle height sensor 7 generates a signal of "neutral" or "high". That is, assuming that condition, when the traveling state of the vehicle is predicted to be in a transient state from the detection signal of the traveling state sensor 11, the controller 15 gives an actuation signal to the actuator 6 to cause the main chamber 4 of the air suspension 1 to operate. And the sub-chamber 5 are cut off from each other to increase the spring constant and make it stiff. The transitional state of the vehicle is a transitional state in which the traveling state of the vehicle changes, and specifically, the state of start, acceleration, deceleration, etc. of the vehicle. . When adjusting the spring constant in such a transient state, the vehicle height is not adjusted.

As described above, when the vehicle height sensor 7 generates a signal of "neutral" or "high", the adjustment of the spring constant has priority over the vehicle height adjustment. When the transient state has passed,
The controller 15 connects the main chamber 4 and the sub chamber 5 and restores them to the original state.

On the other hand, when the vehicle height sensor 7 generates a "low" signal, the spring constant is not adjusted even if the running state of the vehicle is expected to be in a transient state. Therefore, at this time, the vehicle height adjustment has priority over the spring constant adjustment.

By the way, when the vehicle height sensor 7 is generating a "low" signal, the main chamber 4 and the sub chamber 5 of the air suspension 1 are
This is when the inside air pressure is abnormally low and the vehicle height is extremely low. The request for vehicle height adjustment after the vehicle height is adjusted once occurs mostly due to the air leak, and rarely occurs when a transient state is expected. If there is a request, it is only when the vehicle starts. Therefore, by giving priority to the vehicle height adjustment when the vehicle height is low, the air can be quickly replenished and the vehicle can be started.

As the vehicle height sensor 7, it is possible to employ a pressure sensor that obtains the vehicle height from the air pressure in the main chamber 4 of the air suspension 1. Further, it is also possible that the pressurized air from the compressor 8 is once introduced into the air tank to accumulate the pressure, and the pressure in the air tank is used to increase the vehicle height.

[Effects of the Invention] As described above, the control device for an air suspension according to the present invention is effective only when the vehicle height is lower than a predetermined value and extremely low.
Since the vehicle height adjustment is prioritized over the adjustment of the spring constant of the air suspension, the following effects are achieved.

(1) Replacement of air suspension by market service,
Alternatively, when the vehicle height becomes extremely low at the time of starting the vehicle due to air leakage due to non-use for a long period of time, the vehicle height can be immediately adjusted to quickly perform control in the normal transient state.

(2) Since the air pressure in the air suspension is quickly replenished when the vehicle starts, the consideration of the air pressure when exchanging the air suspension can be reduced and the workability thereof can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining one embodiment of the present invention. 1 ... Air suspension, 4 ... Main chamber, 5 ... Sub chamber, 6 ... Actuator, 7 ... Vehicle height sensor, 8 ... Compressor, 9 ... Exhaust solenoid valve, 10 ... Supply / exhaust solenoid valve, 11 ... Running condition sensor.

Claims (2)

[Claims] 1. An air suspension that controls a spring constant in response to air communication and interruption of air between a main chamber and a sub chamber and changes vehicle height in response to air supply and exhaust to the main chamber. A running state sensor that detects the running state of the vehicle, a vehicle height sensor that detects the vehicle height, an air suspension is controlled based on a detection signal from the vehicle height sensor, and the vehicle height is adjusted. An air suspension control device comprising a controller that adjusts a spring constant of an air suspension according to a traveling state of a vehicle detected by the traveling state sensor, in preference to high adjustment, wherein the controller is the vehicle height sensor. When the vehicle height detected by is less than a predetermined height, the air suspension is controlled and the vehicle height is controlled by giving priority over adjustment of the spring constant regardless of the running condition. An air suspension control device characterized by being raised to a predetermined height. 2. The air suspension control device according to claim 1, wherein the vehicle height sensor is a pressure sensor for obtaining a vehicle height based on a pressure in a main chamber of the air suspension.