JPS60255515A - Electronically controlled suspension device - Google Patents

Abstract

PURPOSE:To prevent the increase of consumption of battery power source by installing an aimed car-height setting means for reserving car-height adjustment by a controller only for a set time after the release of the judgement for bad road. CONSTITUTION:A car-height sensor 22 consists of a front car-height sensor 22F and a rear car-height sensor 22R, and a car-speed sensor 27 is built into a speedometer 26, and each detection signal is supplied into a control unit 25. Further, an acceleration sensor 28 as car-posture sensor for detecting the change of posture of a chassis is installed, and a signal is read into the unit 25. The judgement for bad road is performed according to the outputs of the sensors 22F, 22R, and 28, and the aimed car-height is set high. It is judged that 12sec lapses after the release of the judgement for bad road or not, and when the judgement is NO, car-height adjustment is reserved, in other words, supply and discharge of air in each suspension unit S are brought into stop, and the increase of the consumption of battery power source is prevented.

Description

[Detailed Description of the Invention] This invention provides a vehicle height adjustment device that can adjust the vehicle height in three stages: "high,""medium," and "low." The present invention relates to an electronically controlled suspension device that sets a target vehicle height high when it is determined that the vehicle height is high, and suspends vehicle height adjustment for a set time after the rough road determination is canceled.

Conventionally, when driving on rough roads, the purpose of raising the vehicle height is to increase the vehicle's minimum ground clearance, reduce contact between the road surface and the vehicle body, improve drivability on rough roads, and reduce damage to the vehicle body. A vehicle height control device is known. A set time (for example, 2 seconds) that determines whether the vehicle is traveling on such a rough road.
Depending on the condition of the rough road, the judgment that the road is bad and the judgment that the road is good are repeated alternately. Not only is the vehicle height adjustment not performed smoothly at high vehicle heights because the vehicle height lowering adjustment is repeated alternately, the amount of air consumed increases and the frequency of compressor operation increases, resulting in increased consumption of battery power. If a vehicle is equipped with a lamp that indicates that the vehicle height is being adjusted, the problem is that the lamp repeatedly turns on and off, reducing the reliability of the system.

This invention has been made in view of the above points, and its purpose is to provide a vehicle height sensor or If the acceleration sensor determines that the vehicle is driving on a rough road, the target vehicle height is set high, and after the rough road determination is canceled, vehicle height adjustment is suspended for a set period of time, thereby increasing battery power consumption. An object of the present invention is to provide an electronically controlled suspension device that can prevent such problems.

An embodiment of this invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a car equipped with this device. As shown in mlh, a front air suspension unit FS (FSz, FSz) is interposed between the left and right ends of the front wheel FA side axle and the vehicle body B side member, and the rear air suspension unit FS (FSz, FSz) Rear air suspension units R8 (R81, R8, ?) are interposed between the left and right ends and the vehicle body B side member, respectively.

Cholera air suspension unit) FSl.

FSz, R81, R82)i Since the drawings are the same as those for the front and rear, the air The suspension unit will be explained using the symbol S, and only the parts necessary for vehicle height control will be illustrated and explained.

In other words, these air suspension units) S are:
A strut-type damping force switching type shock absorber 1 is incorporated, and this shock absorber 1 has a front wheel F.
It has a cylinder attached to the A side or the rear wheel BA side, and a piston that is slidably inserted into this cylinder.The cylinder moves up and down with respect to the piston rod 2 in response to the up and down movement of the wheel, thereby generating a shock. absorber 1
It has a damping function depending on the position of the shutter inside, making it possible to effectively absorb shock.

By the way, a main air spring chamber 3 which also serves as a fluid chamber for adjusting vehicle height is disposed coaxially with the piston rod 2 in the upper part of the shock absorber 1, and a part of this main air spring chamber 3 is Since it is formed of bellows 4, the piston rod 2 can be moved up and down by supplying and discharging air to the main air splash chamber 3.

Further, a sub air spring chamber 5 is disposed coaxially with the piston rod 2 above the finger of the main air spring chamber 3 .

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 6a facing upward, and the outer wall of the sub air spring chamber 5 is provided with a spring receiver 6b facing downward. Receiving 6a.

A coil spring 7 is loaded between 6b.

-Furthermore, these air splash chambers 3, 5 are connected to each other via a communication passage 9 bored in a control rod 8 rotatably inserted into the piston rod 2; An on-off valve 10 forming a spring constant switching mechanism is interposed in the passage 9.

This on-off valve 10 includes a first valve part 10a that cuts off communication between the auxiliary air splash chamber 5 and the communication passage 9, a main air spring part 10a, and a second valve part that cuts off communication between the secondary air splash chamber 3 and the communication passage 9. Part 10b
It is composed of:

Therefore, when the on-off valve 10 is in the open mode, the main air splash chamber 3 and the auxiliary air spring 5 can be in communication with each other (and the spring constant can be made small (soft)), and the on-off valve 10 When in the closed mode, the main air splash chamber 3 and the sub air splash chamber ￥5 are cut off: :: and the spring constant is increased ()\-de)
It is possible.

That is, by rotating the control rod 8, the on-off valve 10 can be opened and closed, and by this opening and closing, the spring chamber capacity can be changed.

By changing this spring chamber capacity, the spring constant of the suspension can be changed.

Furthermore, a control valve 8a is provided at the lower end of the control rod 8, which can change the orifice area of the piston 1a of the shock absorber 1. This control valve 8
a is to reduce the damping force by increasing the orifice area of the piston 1a when the on-off valve 10 is in the open mode using the control rod 8, and to reduce the orifice area of the piston 1a when the 7M4 closing valve 10 is in the closed mode. It is configured to increase the damping force.

Thus, the vehicle height adjustment of the automobile is carried out by the configuration shown in ffJ 2 I71. That is, as shown in FIG.
, the rear solenoid valve 14, the front solenoid valve 15, the piping 16 that connects these, and the connection port 17 that communicates with the communication passage 9 in the partially pipe-shaped control rod. It has become so.

The compressor f1 compresses the air sent from the air cleaner 18 and supplies it to the dryer 12. The compressed air dried by silica gel etc. in the dryer 12 is as shown by each solid line arrow in FIG. It is then supplied to the suspension unit 8. Also, when compressed air is exhausted from the suspension unit)
Exhaust solenoid valve 1 as shown by each dashed arrow in the figure.
9, the compressed air is released to the atmosphere.

A reserve tank 20 is connected to the dryer 12, and a portion of the compressed air is supplied from the reserve tank 20 to each suspension unit S via an air supply solenoid valve 21tr.

Further, as shown in FIG. 2, a vehicle height sensor 22 is provided, and this vehicle height sensor f22 is attached to the lower arm 23 of the front right side suspension of the vehicle to detect the front vehicle height of the vehicle. A vehicle height sensor 22F and a rear vehicle height sensor 22 that is attached to the lateral rod 24 of the rear left suspension of the vehicle and detects the rear vehicle height of the vehicle.
These vehicle height sensors 2
A front vehicle height detection signal and a rear stop height detection signal are supplied from zF and 22R to a control unit 25 serving as a vehicle height adjustment control section.

Each sensor 22F in the vehicle height sensor 22.

22R connects one of the Hall IC element and the magnet to the wheel FA.
The sensor is mounted on one side and the other on the vehicle body to detect the distance from the normal vehicle height level and the low or high vehicle height level, respectively. It should be noted that the vehicle height sensor may be of any other type, such as one using a transistor.

Furthermore, the speedometer 26 has a built-in vehicle speed sensor 27, which detects the vehicle speed and supplies a detection signal to the control unit 25. A reed switch type vehicle speed sensor is used, and an open collector output type sensor with five transistors is used in the electronic speedometer.

Further, an acceleration sensor 28 is provided as a vehicle attitude sensor for detecting changes in the attitude of the vehicle body, and this acceleration sensor 28 is adapted to detect changes in the attitude of the vehicle body such as pitch, roll, and yaw when the vehicle is bouncing. For example, when there is no acceleration, the weight is in a hanging state, and the light from the light emitting diode is blocked by the shielding plate and does not reach the photodiode, so it is possible to detect the absence of acceleration. There is.

When acceleration acts on the front and back, left and right, or up and down, the weight tilts or moves,
The acceleration state of the vehicle body is detected.

32 is a steering sensor that detects the rotational speed of the steering wheel 33, that is, the steering speed; 34 is an accelerator sensor that detects the operating speed of the accelerator pedal of the engine (not shown); 35 is a three-way switching valve in the reserve tank 20; The three-way switching valve 36 is connected to a position where the pneumatic drive mechanism 35 communicates with the reserve tank 20 by a signal from the control unit 25, and a position where the pneumatic drive mechanism 35 and the reserve tank 20 are communicated with each other. Either one of the positions communicating the mechanism 35 and the atmosphere can be selected, and the control rod 3 is thereby rotated in the opposite direction to a predetermined position, thereby having the function of transitioning from the soft state to the hard state. Note that an air cylinder type drive mechanism may be used instead of the solenoid type drive mechanism 20. Furthermore, the symbol LF indicates the boundary between the engine room (@, to the left of the line LF) and the passenger compartment (between the broken lines LP and LR), and LR indicates the boundary between the passenger compartment and the trunk room (the dashed line L).
(to the right of R). Moreover, the code 30 is
A bump stopper is used to prevent the relative rise of the shock absorber 1 on rough roads, etc. I: indicates a bump stopper for preventing damage to the wall surface of the main air spring chamber 3, etc. Reference numeral 31 is a mode selection switch serving as a high vehicle height selection switch. By the way, this mode selection switch 31
can switch between auto mode, which automatically controls the vehicle height to normal vehicle height or low vehicle height, and high mode, which automatically controls vehicle height to high vehicle height.

Next, the operation of one embodiment of the present invention configured as described above will be explained. First, the overall operation will be explained using the flowchart shown in FIG. First, in step S1, an auto mode is set as an initial setting in which vehicle height adjustment is automatically set to a "medium" or "low" vehicle height. Then, set the target vehicle height to normal, that is, "medium".
The vehicle height is set. Next (Second, the fourth step in step S2)
It is determined whether or not the road direction in which the vehicle is traveling is a rough road, which will be described in detail later with reference to the drawings. Then, in step S3, a target vehicle height determination, which will be described in detail later with reference to FIG. 5, is performed, that is, it is determined to what level the target vehicle height should be set. Then, proceeding to step S4, the vehicle height sensor 22
Vehicle height signal from F (22R) is sent to control unit 25
is loaded into. Then, in step S5, it is determined whether the vehicle height detected by the vehicle height sensor 2zF (zxR) is equal to the target vehicle height set in step S3. If the determination in step S5 is "NO", the process proceeds to step S6 and vehicle height adjustment is started toward the target vehicle height.

For example, if the vehicle height detected in step S4 is lower than the target vehicle height, the vehicle height is raised by supplying air to the main air splash chamber 3 of each suspension unit. On the other hand, if the vehicle height detected in step S4 is higher than the target vehicle height, the main splash chamber 3 of each suspension unit
is exhausted from. Then, the process returns to step S2, and when the vehicle height becomes equal to the target vehicle height in step S5, the process proceeds to step S7, where the vehicle height adjustment in step S6 is completed.

Next, the rough road judgment performed in step S2 of FIG. 3 will be explained in detail with reference to the flowchart of FIG. 4. First, in step 8zo, the vehicle speed is 40km/h.
If it is determined that the value is 1YB8J, the control unit 25 reads the time of the 2-second timer for counting 2 seconds in step 8JJ. and,
In step S12, it is determined whether two seconds have been counted by the two second timer. In this step S12, “
If the determination is NO, the process proceeds to step 81s, where the output signal of the vehicle height sensor 22F (z2R) is read into the control unit 25, and the process proceeds to step S14, where the acceleration (G
) The output signal of the sensor 28 is read into the control unit 25. Then, the process advances to step 815 and the rough road determination is canceled. For example, control unit 2
This is done by resetting the rough road flag that is set when driving on a rough road in the memory area in 5. Thereafter, when 2 seconds have been counted by the 2 second timer, it is determined as YESJ in step S12, and the process proceeds to step S)6. In this step S16, the two second timer is reset. Then, proceed to step 8J7 and proceed to step S13 above.
Vehicle height sensor 22F (22R) to H
It is determined whether the H code, that is, the vehicle height higher than the high stop product level has been output two or more times. If it is determined as "YESI" in this step S17, the process advances to step S18.

In this snap 818, the honesty sensor detected in step S13 above, ? ,? From F (,? 2R), it is determined whether the L L code, that is, the vehicle height lower than the low vehicle level has been output two or more times. This step S18
If it is determined as YESJ in step S19, the rough road determination is established. This is done by setting the rough road flag. On the other hand, if NOJ is determined in step S18, the process proceeds to step S20, where it is determined whether the output signal of the acceleration (0) sensor 28 has been turned on twice or more.

In other words, it is determined whether the output of the acceleration (G) sensor 28 has passed through a state of low acceleration and high acceleration two or more times within two seconds. If it is determined as "YES" in this step S20, the process proceeds to step 821, and it is determined whether the acceleration (the output signal of the Gl sensor 28 was turned on twice or more) during the previous two seconds. “YE
If it is determined to be 'S'J, the process proceeds to step S19, where the rough road determination is established, and in step S21, 'NO' is determined.
”, the process proceeds to step S15 and the rough road determination is canceled.

In this way, a rough road is determined based on the output signal of the east sensor 22F (22R) or the acceleration (G) sensor 28.

Next, the target vehicle height determination carried out in step S3 in FIG. 3 will be explained in detail with reference to FIG. First, in step 831, it is determined whether the rough road determination is established. This step S? If it is determined as "YEJ" in J, the process advances to step S32 and the target vehicle height is set to high (HIG).
H). On the other hand, if it is determined in step S31 that the road condition is l''N' Oj, the process proceeds to step S33, where it is determined whether or not the rough road judgment has been established and has been canceled.If it is determined that I-YESJ in this step S33, the process proceeds to step 8s4. It is determined whether 12 seconds have passed since the rough road determination was canceled.If the determination is "NO" in step S3E, the process advances to step 835 and the vehicle height adjustment is suspended, that is, each Sanupe 7 supply and exhaust to the John unit is stopped. If the determination in step 834 is YES, the process proceeds to step S36, where the suspension of the stop adjustment performed in step 8, vs. is released, and step S, ? 7, it is determined by the mode selection screen 31 whether the automatic (AUTO) mode is selected. If rY'E'SJ is determined in step 837, the process proceeds to step Sss, where it is determined whether the target vehicle height is set to normal (middle). In this step 8.7 s <=, “N
' If determined to be OJ, the process proceeds to step S39, where it is determined whether the vehicle speed detected by the vehicle speed sensor 27 is 70 Km/h or less. If the determination in step S39 is "NO", the process proceeds to step 84o and the target vehicle height is set to "low" (
low) is set.

On the other hand, if it is determined as ``YESI'' in the step 8sg, the process proceeds to step S41, where it is determined whether the vehicle speed detected by the vehicle speed centimeter 27 is 90 Rm/h or more. In step S42, the state where the vehicle speed is 90 Rm/h or more is 1.
It is determined whether 0 seconds have elapsed. This step S42
If it is determined as “YESJ” in step S40,
The target vehicle height is set to low. In other words,
Even if the target vehicle height is normal, the vehicle speed is 90km/7hJd higher than 1.
When 0 seconds have elapsed, the target vehicle height is set low to ensure driving stability. On the other hand, if the determination in step S4x is "NO", the process proceeds to step S43 and the target vehicle height is set to normal (middle).

By the way, if it is determined in step 837 that it is 1-NOJ, that is, the high east high selection mode, step 8
The process proceeds to step 44, where it is determined whether the target main island is set to a high level. In this step 844, “
If it is determined to be YF or 8J, the process proceeds to step 845, where it is determined whether the vehicle speed is 70 km/h or more. This step 8
If the determination in step 4 is "NO", the above step S3 is executed.
Proceed to step 2. On the other hand, in the above step S45, "YES" is selected.
”, the process advances to step S46 and the vehicle speed is 70%.
It is determined whether 10 seconds have passed since K m / h or more.

If the determination in step S46 is "NO", step SJ, ? The process proceeds to step S43, and if it is determined as "YE8J" in step 846, the process proceeds to step S43.

On the other hand, if it is determined that "NOJ" in step S44, the process proceeds to step 847 and the target main island is
The level is determined.

If it is determined as YE8J in this step 847, the process proceeds to step 84B and the vehicle speed is set to 50 Ktn.
/ h or less is determined. If it is determined in this step 848 that "YB8J", the process proceeds to step S32. On the other hand, in steps S4y and 84g, "NO" is determined.
”, the process proceeds to step 838 described above. In this way, vehicle height adjustment is suspended for 12 seconds after the bad road judgment is canceled.

As detailed above, according to the present invention, "high", "medium", "
In the warehouse control device, which can control the vehicle height in three levels (low), if the vehicle height sensor or acceleration sensor determines that the vehicle is driving on a rough road, the target vehicle height is set to high and the rough road determination is canceled. Thereafter, it is possible to provide an electronically controlled suspension device that can prevent an increase in battery power consumption by suspending vehicle height adjustment for a set period of time.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an automatic transmission equipped with this device, FIG. 2 is a diagram of the overall configuration of this device, and FIGS. 3 to 5 are flowcharts for explaining the operation of one embodiment. DESCRIPTION OF SYMBOLS 11... Compressor, 25... Control unit, 27... Vehicle speed sensor, 31... Mode selection switch. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure M 4

Claims (1)

[Claims] A hydraulic suspension unit that is interposed between a wheel side part of a vehicle and a vehicle body side member and has a fluid chamber for adjusting vehicle height, an acceleration sensor that detects vehicle height, and a vehicle obtained by the vehicle height sensor. A control device that controls the fluid so as to change the vehicle height to the target vehicle height by comparing the high detection signal with a set target vehicle height, and is also capable of setting three target vehicle heights: high, medium, and low. , a rough road determining means for determining whether the vehicle is traveling on a rough road based on the vehicle height sensor or the acceleration sensor; An electronically controlled suspension device comprising a target vehicle height membrane and foot means for suspending vehicle height adjustment by the control device for a set time after the determination is canceled.