JPH0628967B2 - Vehicle height control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a device for controlling the height of a vehicle (that is, vehicle height), and more particularly, to a turning state of a vehicle, an acceleration / deceleration state,
The present invention relates to a vehicle height control device for accurately adjusting a vehicle height in a state in which a vehicle body posture is changing, such as a vehicle body vertical vibration state.

[Conventional technology]

As a conventional vehicle height control device, for example, the one described in “Service Weekly Report No. 428 Leopard”, published by Nissan Motor Co., Ltd., page 123, is known.

In this conventional device, when the actual vehicle height value detected by the vehicle height sensor continues to be out of the target vehicle height range, the actual vehicle is delayed by a delay time (for example, 10 seconds) preset by the delay circuit. The vehicle height adjustment operation is started so that the high price falls within the target vehicle height range, and this prevents malfunction of vehicle height adjustment when the actual vehicle price temporarily deviates from the target vehicle height range. I have to.

Further, as another conventional vehicle height control device, for example, one disclosed in Japanese Patent Laid-Open No. 58-36712 is known.

In this conventional device, the vehicle height adjusting operation is stopped when the vehicle is in an acceleration / deceleration state.

[Problems to be solved by the invention]

However, in such a conventional vehicle height control device, in the former case, the turning state of the vehicle in which the vehicle body rolls, the acceleration / deceleration state in which the vehicle body scouts or nose dives, and the vertical vibration of the vehicle body such as bottoming and bouncing. Since the vehicle height adjustment may be performed even when the vehicle body posture is changing, such as in a state, the vehicle height adjustment in such a vehicle body posture changing state is unnecessarily or erroneously performed and becomes inaccurate. There is a problem in that the adjustment frequency also increases.

In the latter case, although the vehicle height adjustment is not performed in the acceleration / deceleration state, the timer as a delay circuit that delays the start of the vehicle height adjustment operation was operated even in such an acceleration / deceleration state. There is a problem that unnecessary vehicle height adjustment is performed immediately after the acceleration / deceleration state ends. Also, when the vehicle height is crazy, the timer is cleared each time the vehicle height temporarily takes an appropriate value due to the acceleration / deceleration state of the vehicle, which delays the start of the vehicle height adjustment operation. There was also.

The present invention has been made in view of such conventional problems, and it is possible to perform an unnecessary and erroneous vehicle height adjusting operation in a vehicle body posture change state such as a turning state, an acceleration / deceleration state, and a vehicle body vertical vibration state. It is an object of the present invention to provide a vehicle height control device that prevents the vehicle height and accurately adjusts the vehicle height in such a state.

[Means for solving problems]

Therefore, as shown in FIG. 1, the vehicle height control device of the present invention includes: a suspension device having a fluid chamber capable of supplying and discharging a fluid; a fluid supply source for supplying the fluid to the fluid chamber; Vehicle height detecting means for detecting the actual vehicle height;
Vehicle height determining means for comparing the actual vehicle height value with a preset target vehicle height area; vehicle height adjusting operation when the actual vehicle height value is determined to be outside the target vehicle height area Delay means for delaying the start; after delaying the start of the vehicle height adjustment operation by the delay means, fluid is supplied from the fluid supply source to the fluid chamber or from the fluid chamber according to the determination result of the vehicle height determination means. In a vehicle height control device equipped with vehicle height adjusting means for adjusting the vehicle height of the wheel portion so that the actual vehicle height value falls within the target vehicle height region by discharging fluid, the vehicle body posture is changing. A vehicle body attitude change state detecting means for detecting that; and a delay operation holding means for holding a delay operation by the delay means while the vehicle body attitude change state detecting means detects that the vehicle body attitude is changing. With and It is characterized by that.

[Action]

When the actual vehicle height value detected by the vehicle height detection means is determined to be outside the target vehicle height range by the vehicle height determination means, the start of the vehicle height adjustment operation is delayed by the delay time set in advance by the delay means. However, when the delay means is operating in this way, it is possible that the vehicle body attitude change state detection means is changing the vehicle body attitude such as the turning state, acceleration / deceleration state, and vehicle body vertical vibration state. While being detected, the delayed operation holding means holds the delayed operation. Then, when the vehicle body attitude change state is eliminated, the holding operation is released and the operation of the delay means is restarted, and when the delay operation is completed, according to the determination result of the vehicle height determination means,
The vehicle height of the wheel portion is adjusted by supplying the fluid from the fluid supply source to the fluid chamber or discharging the fluid from the fluid chamber by the vehicle height adjusting means so that the actual vehicle height value falls within the target vehicle height region. is there.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

The configuration will be described with reference to FIG.

First, the air system will be described. 1a to 1d are the vehicle body 2 and the front left wheel, front right wheel, rear left wheel, rear right wheel (all are not shown).
Is a suspension device interposed between and, and the suspension devices 1a to 1d include air chambers 3a to 3d and shock absorbers 4a to 4d. Air chambers 3a-3d
Is formed of elastic bodies 5a to 5d made of, for example, rubber or the like that surround the space between the vehicle body 2 and the shock absorbers 4a to 4d in a vertically expandable and contractible manner.

6 is a compressor as an air supply source for supplying air to the air chambers 3a to 3d, and 7 is a dryer for dehumidifying the air sent from the compressor 6.

Reference numerals 8a to 8d are supply / discharge valves provided on the inlet side of the air chambers 3a to 3d, 9 is an exhaust valve provided on the outlet side of the compressor 6, and the valves 8a to 8d and 9 are electromagnetic solenoids for opening and closing the valves. It has 10a-10d, 11.

Next, the electric system will be described. 12a to 12d are vehicle height sensors, and the vehicle height sensors 12a to 12d are, for example, the air chambers 3a to 3d of the suspension devices 1a to 1d.
Used for detecting the relative displacement between the vehicle body 2 and each wheel is used in the vicinity of. Reference numeral 13 denotes a steering angle sensor that outputs a signal corresponding to the steering angle of the steering wheel, and detects the roll state of the vehicle based on the steering angle signal. Reference numeral 14 denotes an accelerator opening sensor that outputs a signal corresponding to the accelerator opening, and detects the acceleration state of the vehicle based on the accelerator opening signal. Reference numeral 15 is a brake switch. This brake switch 15 is linked with, for example, a brake pedal (not shown), and outputs a signal that is turned on when the brake pedal is depressed and turned off when the brake pedal is not depressed. Detects that the vehicle is decelerating.

16 is a battery, 17 is a relay, 18 is a compressor 6
Is a motor for driving.

19 is a controller, and this controller 19
Microcomputer 20 and vehicle height sensors 12a-12
The multiplexer 21 that switches the detection signal of d and the vehicle height sensor 12a selected by this multiplexer 21.
.About.12d, an A / D converter 22 for converting an analog amount detection signal into a digital signal, and an electromagnetic solenoid 10a.
Driving circuits 23a to 23d, 24 for driving 10d, 11
And a drive circuit 25 that drives the relay 17.

The microcomputer 20 has an interface circuit 26.
And arithmetic processing unit 27 and storage unit 28 such as RAM and ROM
And a steering angle sensor 13 and an accelerator opening sensor 1 on the input port side of the interface circuit 26.
4, brake switch 15, multiplexer 21 and A
The / D converter 22 is connected, and the drive circuits 23a to 23d, 24, 25 are connected to the output port side.

The arithmetic processing unit 27 includes detection signals from the vehicle height sensors 12 a to 12 d selected by switching the multiplexer 21 via the interface circuit 26 and the steering angle sensor 1.
3, each detection signal from the accelerator opening sensor 14 and the brake switch 15 is read, and the calculation and other processes described later are performed based on these detection signals. Further, the storage device 28 stores a predetermined program necessary for executing those processes, and also stores a processing result of the arithmetic processing device 27 and the like.

Next, the operation of the above embodiment will be described.

Turn on the ignition switch and turn on the controller 19
When the power of is turned on, the vehicle height control operation is started. The multiplexer 21 is switched by the drive signal from the interface circuit 26 of the microcomputer 20, the analog amount detection signals from the selected vehicle height sensors 12a to 12d are converted into digital signals by the A / D converter 22, and the interface is obtained. Is supplied to the circuit 26,
The interface circuit 26 outputs a signal according to the steering angle from the steering angle sensor 13, a signal according to the accelerator opening from the accelerator opening sensor 14, and a signal from the brake switch 15 indicating whether or not braking is being performed. Is supplied to.

FIG. 3 shows a procedure of processing executed by the microcomputer 20. This process is preferably executed as a timer interrupt at every predetermined period Δt (for example, 20 ms).

Then, the processes of steps 1 to 3 of FIG.
During t, it is executed once for each of the front, rear, left and right four wheels.

In FIG. 3, first, in a step, the multiplexer 2
The actual vehicle height value h is read from the detection signal of the vehicle height sensor 12 selected by 1, and then the process proceeds to step to calculate the average value h _M of the actual vehicle height value h. This average vehicle height h
_M is calculated, for example, by obtaining a moving average of n detection values in the current and past (n-1) control cycles of the actual vehicle height value h. Next, in step S12, the value of the steering angle θ is read from the detection signal of the steering angle sensor 13, and the value of the accelerator opening α is read from the detection signal of the accelerator opening sensor 14.

Then, the process shifts to a step to check whether or not the vehicle is in a turning state. This is because, for example, the value of the steering angle θ read in step is compared with a predetermined value θ _0, and when θ ≧ θ _0, it is determined that the vehicle is in a turning state, and θ <θ ₀ . Sometimes it is determined that the vehicle is not in a turning state.

When it is determined that the vehicle is not in the turning state in step, the process proceeds to step and it is checked whether or not the vehicle is in the accelerating state. This is done, for example, by comparing the value of the accelerator opening α read in step with a predetermined value α _0, and when α ≧ α ₀ , it is determined that the vehicle is in an accelerating state, and α <α ₀ At some time, it is determined that the vehicle is not in an accelerating state.

When it is determined that the vehicle is not in the accelerating state in the step, the process proceeds to the step and it is checked whether or not the vehicle is in the decelerating state. This is, for example, the brake switch 1
If the signal is on, the vehicle is in the braking state, that is, in the deceleration state, and if the signal is off, the vehicle is not in the braking state, that is, not in the deceleration state.

When it is determined that the vehicle is not in the deceleration state in step, the process proceeds to the next step, and it is checked whether or not the vehicle body is vibrating in the vertical direction. This is, for example,
The absolute value of the difference between the actual vehicle height value h read in step and the average vehicle height value h _M calculated in step is calculated, and that value is compared with a predetermined value Δt. And | h-
If h _M | ≧ Δh, it is determined that the vehicle is in the vertical vibration state, and if | h−h _M | <Δh, it is determined that the vehicle is not in the vertical vibration state.

The processing from these steps to is processing for detecting a state in which the vehicle body posture is changing.

When it is determined that the vehicle body is not vertically vibrating in the step, the process proceeds to the next step, and the average vehicle height value h _M calculated in the step is lower than the preset lower limit value _HL of the target vehicle height region. Check if it is low. h _M −H _L ≧
0, that is, when the average vehicle height value h _M is higher than the lower limit value H _L , the process proceeds to the next step, the value of the counter T _U for delaying the start of the vehicle height increase adjustment is reset, and then the process proceeds to the step. To do.

Also, h _M -H _L <0 in step, i.e., when the average vehicle height h _M is less than the lower limit value H _L is then the process proceeds to step, the value of the counter T _U by a predetermined value or control cycle Δt Add, then move to step.

In step, the average vehicle height h _M calculated in step
Is higher than the preset upper limit value H _H of the target vehicle height region. When h _M −H _H ≦ 0, that is, when the average vehicle height value h _M is lower than the upper limit value H _H , the process proceeds to the next step, and the value of the counter T _D for delaying the vehicle height decrease adjustment start is reset. And then move to step.

Further, when h _M −H _H > 0 in step, that is, when the average vehicle height value h _M is higher than the upper limit value H _H , the process proceeds to the next step, and the value of the counter T _D is set to a predetermined value, that is, the control cycle Δt. Add, then move to step.

In step, it is checked whether or not the value of the counter T _U reaches _or exceeds a predetermined value T _0U corresponding to a preset delay time,
If not, the process proceeds to the next step, and it is determined whether or not the value of the counter T _D has reached a predetermined value T _0D (= T _0U ) corresponding to a preset delay time or more. Check, and if not reached, move to the next step,
The vehicle height is not adjusted.

When the vehicle height is not adjusted, in FIG. 2, the interface circuit 26 supplies a control signal of “L (low level, or logical value“ 0 ”)” to the drive circuit 25 to turn off the relay 17 and turn off the motor 18. And the compressor 6 are stopped. Then, the drive circuit 23 for driving the supply / discharge valve 8 and the drive circuit 2 for driving the exhaust valve 9 of the wheel portion corresponding to the vehicle height sensor 12 being selected from the interface circuit 26.
The control signal “L” is supplied to the control circuit 4 to deactivate the corresponding electromagnetic solenoids 10 and 11 to close the supply / discharge valve 8 and the exhaust valve 9.

Returning to FIG. 3, when it is determined in step that the value of the counter T _U for delaying the start of vehicle height increase adjustment has reached the predetermined value T _0U or more, the process proceeds to step and Make adjustments to increase the vehicle height of the wheel parts.

The adjustment for increasing the vehicle height is performed by the drive circuit 23 for driving the supply / discharge valve 8 of the wheel portion corresponding to the vehicle height sensor 14 currently selected from the interface circuit 26 in FIG.
(High level or logical value “1”) ”, the corresponding electromagnetic solenoid 10 is energized to open the supply / discharge valve 8, and the interface circuit 26 sends the control signal“ drive signal 25 ”to the drive circuit 25. H "is supplied to the relay 16
Is turned on, the motor 17 is driven, and the compressor 6 is driven. As a result, air is supplied from the compressor 6 to the air chamber 3 of the suspension device 1 at the corresponding wheel portion, and the vehicle height rises.

Returning to FIG. 3, in the step, when it is determined that the value of the counter T _D for delaying the vehicle height lowering adjustment has reached the predetermined value T _0D or more, the process proceeds to the next step, and the wheel concerned. Make adjustments to lower the vehicle height of the part.

In the adjustment for lowering the vehicle height, in FIG. 2, the control signal “H” is supplied from the interface circuit 26 to the drive circuit 23 for driving the supply / discharge valve 8 of the wheel portion corresponding to the selected vehicle height sensor 14, The electromagnetic solenoid 10 is energized to open the corresponding supply / discharge valve 8, and the interface circuit 26 supplies the control signal “H” to the drive circuit 24 to energize the electromagnetic solenoid 11 and open the exhaust valve 9. Is done by As a result, air is discharged from the air chamber 3 of the suspension device 1 of the corresponding wheel portion to the outside through the supply / discharge valve 8 and the exhaust valve 9, and the vehicle height is lowered.

Returning to FIG. 3, when the value of the steering angle θ is greater than or equal to the predetermined value θ ₀ (θ ≧ θ ₀ ) in step, that is, when it is detected that the vehicle is turning, or in step When the value of the accelerator opening α is equal to or greater than a predetermined value α ₀ (α ≧ α ₀ ), that is, when it is detected that the vehicle is in an acceleration state, or in the step,
When the signal of the brake switch 15 is ON, that is, when the vehicle is detected to be in the braking state, that is, the decelerating state, or in step, the absolute value of the difference between the actual vehicle height value h and the average vehicle height value h _M is predetermined. Value Δh or more (| h-
When h _M | ≧ Δh), that is, when it is detected that the vehicle body is vertically vibrating, this is the case where a state in which the vehicle body posture is changed is detected. in this way,
When the state in which the vehicle body posture is changed is detected, the above steps 1 to 3 are skipped, the process proceeds to step, and the vehicle height is not adjusted as described above.

That is, in such a state in which the vehicle body posture is changed, the value of the counter T _U or T _D for delaying the start of the vehicle height increase adjustment or the vehicle height decrease adjustment is not reset or added, but the value thereof is changed. Hold as is. Therefore, the delay operation until the vehicle height adjustment is started is maintained as it is in the vehicle body attitude changing state, and the delay operation is restarted when the vehicle body attitude changing state ends.

FIG. 4 shows a first specific example of the operation of the above-described embodiment, and acceleration is performed when the average vehicle height h _M of the actual vehicle height h is within the target vehicle height region and vehicle height adjustment is not necessary. The operation of the front right wheel part in the case is shown.

In the figure, acceleration is performed between times t _{1 and} t ₃ , and at time t ₂ , the average vehicle height value h _M is the upper limit value H of the target vehicle height region.
Cross _H

In the present invention, even if the average vehicle height value h _M exceeds the upper limit value H _H at the time t ₂ , it is still in an accelerating state. Therefore, the value of the counter T _D for delaying the start of the vehicle height lowering adjustment is neither reset nor added. It is held as it is without being performed. And time t
After the acceleration state ends in ₄ , the average vehicle height value h _M is equal to or higher than the upper limit value H _H , so that the counter T _D is incremented. However, at time t ₅ , the average vehicle height value h _M returns to the original proper value and falls within the target vehicle height region, so the counter T _D is reset without reaching the predetermined value T _0D , and therefore the vehicle height decrease adjustment is performed. Not done

On the other hand, in the conventional example, when the average vehicle height value h _M exceeds the upper limit value H _H at time t ₂ after the start of acceleration at time t ₁ , addition of the counter T _D is started and the acceleration state continues. also the addition between the time t ₂ ~t ₄ is continued, the vehicle height downward adjustment request is turned beyond a predetermined value T _0D at time t _3. However, since the vehicle is in an accelerated state, the downward adjustment is not performed. However, since the addition of the counter T _D is continued even in the acceleration state, the vehicle height lowering adjustment is started at time t ₄ when the acceleration state ends, and the vehicle height lowering adjustment is performed until time ₅ . That is, at the end of the acceleration state, an unnecessarily downward adjustment is made.

FIG. 5 shows a second specific example of the operation of the above-described embodiment, and when the average vehicle height value h _M of the actual vehicle height value h is higher than the target vehicle height region and vehicle height adjustment is required, left turning and braking are performed. The operation of the right front wheel region when the robot is broken is shown.

In the figure, after time t _{1, the} average vehicle height value h _M is the upper limit value H.
_The counter T _D is started to be added after exceeding _H , then the vehicle makes a left turn between times t _{2 and} t ₅ , and braking is performed between times t ₆ and t ₉ .

In the present invention, the counter T _D is added after the time t _{1, and} the value of the counter T _D is held at the value of the time t ₂ in the left turning state between the times t _{2 and} t ₅ , and the time when the left turning is completed. After t _{5, the} counter T _D is added again. In the deceleration state due to braking between times t ₆ and t ₉ , the counter T _D holds the value at time t ₆ , and the addition is performed again after time t ₉ when braking ends,
Since the value of the counter T _D exceeds the predetermined value T _0D at time t ₁₀ , the vehicle height lowering adjustment is quickly started, and the vehicle height lowering adjustment is completed at time t ₁₁ when the average vehicle height value h _M falls within the target vehicle height region. To do.

On the other hand, in the conventional example, the value of the counter T _D , which started the addition at the time t ₁ , continues to be added even in the left turning state after the time t _2, but the average vehicle height value h
_It is reset at time t ₃ when _M becomes lower than the upper limit value H _H. Then, when the average vehicle height value h _M exceeds the upper limit value H _H at time t ₄ in the left turning state, the counter T _D starts the addition. However, at time t ₇ , when the average vehicle height h _M becomes lower than the upper limit H _H due to braking, the value of the counter T _D is reset again, and at time t ₈ , the average vehicle height h _M is the upper limit H _H. After exceeding T, counter T
The value of _D is added. In this way, conventionally, the value of the counter T _D is reset every time the average vehicle height value h _M falls temporarily within the target vehicle height region due to the turning state or braking, so that these turning and braking operations are performed. After the completion, the vehicle height adjustment, which should be performed originally, was delayed, and the vehicle height did not easily fall within the target vehicle height range.

In the embodiment described above, the one using air pressure as the pressure fluid has been illustrated, but the present invention is not limited to this, and hydraulic pressure or other appropriate pressure fluid can be used.

In addition, although the one that uses a compressor as a fluid supply source is illustrated, in addition to this compressor, a reservoir tank that can supply pressure fluid from the compressor to store the pressure is installed, and when adjusting the vehicle height to rise, Alternatively, the compressor may be driven by the storage pressure of the reservoir tank, and the compressor may be replenished when the pressure of the reservoir tank is reduced, or driven when the pressure of the reservoir tank is low and the vehicle height increase adjustment is required.

Further, in FIG. 1 to FIG. 3, the processing of steps, is a concrete example of the vehicle height determination means, steps ,.
,,, is a specific example of the delay means, the supply / discharge valves 8a-8 having electromagnetic solenoids 10a-10d, 11
d, exhaust valve 9, relay 16 and drive circuits 23a-2
3d, 24, 25 and the processes of steps 1 to 3, the vehicle height adjusting means includes a vehicle height sensor 12a to 12d, a steering angle sensor 13, an accelerator opening sensor 14, a brake switch 15 and the processes of steps 1 to 3. A specific example of the posture change state detecting means and a specific example of the delay action holding means for the processes of steps 1 to 3 will be shown.

Further, the controller configured by using a microcomputer is shown, but instead of this, an electronic circuit such as an arithmetic circuit, a comparison circuit, a logic circuit, a command value setting circuit, and a timer circuit is combined to configure the controller. It is also possible.

〔The invention's effect〕

As described above, the vehicle height control device of the present invention is a vehicle height control device configured to delay the vehicle height adjustment start by a predetermined time when it is detected that the vehicle height deviates from the target vehicle height region. When a state in which the vehicle body posture is changing, such as a turning state of the vehicle, an acceleration / deceleration state, and a vertical vibration state of the vehicle body, is detected, the delay operation is held while the state is detected. Prevent unnecessary and erroneous vehicle height adjustment immediately after the body posture change state is finished, or quickly perform the originally required vehicle height adjustment when the body posture change state is finished, and perform the original vehicle height adjustment accurately. The effect that can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a vehicle height control device of the invention, FIG. 2 is a configuration diagram showing an embodiment of the invention, and FIG.
FIG. 4 is a flow chart showing the processing procedure of the above embodiment executed in a microcomputer, and FIGS. 4 and 5 are time charts showing the first and second concrete examples of the operation of the above embodiment, respectively. 1a-1d ... Suspension device, 3a-3d ... Air chamber, 4a-4d ... Shock absorber, 5a-5d
...... Elastic body, 6 ...... Compressor, 8a to 8d ...... Supply and exhaust valve, 9 ...... Exhaust valve, 10a to 10d, 11 ......
Electromagnetic solenoids, 12a-12d ... Vehicle height sensor, 13
...... Steering angle sensor, 14 …… Accelerator opening sensor, 15
... Brake switch, 17 ... Relay, 18 ... Motor, 19 ... Controller, 20 ... Microcomputer, 23a-23d, 24,25 ... Drive circuit, 26
... Interface circuit, 27 ... Arithmetic processing unit, 28
……Storage device.

Front Page Continuation (72) Inventor Kazunobu Kawabata 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP 58-149815 (JP, A) , U)

Claims (1)

[Claims] 1. A suspension device having a fluid chamber capable of supplying / discharging fluid; a fluid supply source for supplying fluid to the fluid chamber; vehicle height detecting means for detecting an actual vehicle height value of a wheel portion; Vehicle height determining means for comparing and comparing with a preset target vehicle height area; when the vehicle height determining means determines that the actual vehicle height value is out of the target vehicle height area, a vehicle height adjusting operation is started. Delaying means for delaying the start of the vehicle height adjusting operation by the delaying means, and then supplying the fluid from the fluid supply source to the fluid chamber or the fluid according to the determination result of the vehicle height determining means. In a vehicle height control device including a vehicle height adjusting unit that adjusts the vehicle height of the wheel portion so that the actual vehicle height value falls within the target vehicle height region by discharging fluid from the chamber, Detected that A vehicle body attitude change state detecting means; and a delay operation holding means for holding the delay operation by the delay means while the vehicle body attitude change state detecting means detects that the vehicle body attitude is changing. A vehicle height control device characterized by being provided.