JPH0525682B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a vehicle height adjustment device, and particularly to a method for determining the start of adjustment of a device that automatically adjusts vehicle height based on load, vehicle speed, and other input information. This is related to the improvement of.

[Prior art]

Conventionally, a vehicle height adjustment device that uses a sensor capable of detecting changes in vehicle height to adjust the vehicle height to a target position has been proposed in Japanese Patent Application Laid-Open No. 56-60711. By the way, in the conventional device, the number of pulses generated by the pulse converter group corresponding to each vehicle height region is counted for a predetermined period of time, and the varying vehicle height is averaged based on the magnitude relationship of the counts. For this reason, when using a vehicle height sensor that has multiple vehicle height target values and detects multiple vehicle height regions, the conventional method requires a very complex determination circuit to average the vehicle height. There was a drawback. Furthermore, since this averaging method requires 2 to 5 seconds for averaging, there is a delay especially when the vehicle is stopped or when the vehicle height adjustment is started or stopped by detecting a passenger getting on or off the vehicle. Since time is an issue, this averaging is not used and vehicle height adjustment is started and stopped directly using vehicle height area signals. For this reason, not only is a complicated switching of the control method required, but the vehicle height is frequently controlled when the vehicle is stopped, which gives an unfavorable impression to the occupants and shortens the life of the adjustment mechanism due to unnecessary operation. There were some drawbacks that led to a decline. Furthermore, if vehicle height adjustment is started due to an increase in the number of passengers while the vehicle is stopped, and the vehicle immediately starts moving even though the vehicle height adjustment has not been fully completed, the vehicle may roll or pitch when starting. A drawback is that once vehicle height adjustment is stopped, it takes too long to resume normal vehicle height adjustment.

[Summary of the invention]

The present invention is intended to eliminate the above drawbacks, and its purpose is to easily, accurately, and quickly average the vehicle height even when a vehicle height sensor that detects multiple vehicle height regions is used. The purpose is to provide a vehicle height adjustment device that can perform optimal vehicle height adjustment both when stopped and when driving, and when vehicle height adjustment is necessary, as much as possible. To provide a vehicle height adjustment device that can quickly adjust the vehicle height, but can prevent unnecessary vehicle height adjustment when unnecessary.

[Embodiments of the invention]

FIG. 1 is a basic configuration diagram of a vehicle height sensor according to an embodiment of the present invention. In the figure, 1 is a vehicle body, 3 is a vehicle height sensor attached to the vehicle body 1, 9 is a rod attached to a wheel or axle 2, 8 is an arm of the vehicle height sensor 3 connected to the rod 9, which is connected to the slit 7. 4, 5, and 6 are photo interrupters,
Depending on the rotation angle of the slit 7, an on/off pattern of electrical signals is output based on the on/off pattern of the light processed into the slit 7. In the vehicle height sensor 3 configured as described above, when the vehicle height between the vehicle body 1 and the wheel or axle 2 changes, the rod 9 and arm 8 move, the slit 7 rotates, and the interrupter 4, 5, 6 A code corresponding to the high level is output as a detection signal. In this example, maximum 2 ³ = 8
It is possible to detect two areas. FIG. 2 shows a suspension 10 with a vehicle height adjustment function that constitutes a vehicle height adjustment mechanism according to an embodiment of the present invention.
12 is a coil spring, 12 is an air chamber of the air spring, 13 is an air passage, 14 is a shock absorber, and 15 is a connection portion with an axle. In the suspension 10 configured as described above, by feeding air through the air passage 13, the pressure in the air chamber 12 increases, and the height between the vehicle body 1 and the connection part 15 with the axle, that is, the vehicle height, can be raised. On the contrary, a compressor, an air valve, a reserve tank, an air cleaner, an air dryer, etc. are required to feed or release air, and the vehicle height adjustment means is made up of these. FIG. 3 is a basic configuration diagram of an embodiment of the present invention, in which 21 is a wheel, 22 is a control device, 23,
24 is an air valve, 25 is an exhaust valve, 26 is an air supply valve, 2
7 is a tank, 28 is a pump, 29 is a vehicle speed sensor,
30 is an air pipe. 51 is the key SW signal,
52 door SW signal, 53 is brake SW signal,
54 is a transmission gear position signal, and 55 is an automatic range position signal. In the vehicle height adjustment device configured as shown in FIG. 3, the control device 22
reads information from vehicle height sensors 3a, 3b, vehicle speed sensor 29, etc. and determines whether to start or stop vehicle height adjustment. When performing vehicle height raising control, operate the pump 28 as necessary, open the air supply valve 26, and open the exhaust valve 2.
5, open and close the air valves 23 and 24 as necessary, and adjust the suspensions 10a and 1 with vehicle height adjustment mechanisms.
The vehicle height of the vehicle body 1 is raised via 0b. When performing vehicle height lowering control, the height of the suspension 10 is lowered by closing the air supply valve 26, opening the exhaust valve 25, and opening and closing the air valves 23 and 24 as necessary.
FIG. 4 is an internal configuration diagram of the control circuit 22 in FIG.

Next, the operation of the above embodiment will be explained. The vehicle height sensors 3a and 3b have the structure shown in FIG. 1, and output the code shown in FIG. 5 in response to changes in vehicle height. Code outputs from the vehicle height sensors 3a and 3b are input to the CPU 44 via input circuits 40 and 41. The CPU is approximately the unsprung resonance frequency of the car body.
The vehicle height sensor code is read at a first sampling time that is equal to or higher than the vehicle height sensor code transition speed specified by 12HZ. A sampling time of 3ms to 9ms is desirable. At the same time, the CPU 44 receives input information from the vehicle speed sensor 29 and other input information via the input circuit 42, and determines the target value of the vehicle height. The code of the vehicle height sensor is converted into numbers N ₁ to _{N 5} shown in FIG. 5 according to the target value of the vehicle height, and is taken into the CPU and added at every first sampling time. The total number of the added vehicle height sensors is calculated over a period of time longer than the period of the sprung resonance frequency of the vehicle body, that is, the second
The results averaged every sampling time are sequentially stored in the memory 43. When the latest average value is stored, the contents of the oldest average value are cleared. This second sampling time is
It is sufficient to average the vibrations at the car body's sprung resonance frequency of about 1.4 HZ, so 1 to 2 seconds is desirable. The target value for the vehicle height is a range, and we will consider the average value of the vehicle height when the vehicle height is vibrating large or small. If the vehicle height is higher than the target value, the numbers are 5, if it is the target value, 4, and if it is lower, the numbers are averaged, so the average value will be a value between 3 and 5. Moreover, if the average vehicle height is high, the average value approaches 5, and if it is low, the average value approaches 3. This average value up to the past N times is compared with the target value of 4 to determine whether to start or stop the vehicle height adjustment. If the average values of the past N times are all larger than 4, the vehicle height is controlled to lower, and if the average values of all the past N times are smaller than 4, the vehicle height is controlled to be raised. Perform vehicle height raising control and check whether the latest average value is equal to 4 or not.
If it becomes larger than 4, vehicle height control will stop. Vehicle height lowering control is performed, and when the latest average value of vehicle heights becomes equal to or less than 4, vehicle height control is stopped.
In this way, the vehicle height can be controlled within the target 4 range. Next, let us consider a case where the vehicle height is controlled to be in region 4 in this manner, and the target value of the vehicle height changes to region 2. In this case, since the average value of the vehicle heights over the past N times is always 3 or more and the target value of the vehicle height has been changed to 2, the vehicle height lowering control is immediately started. The determination of whether to stop may be made such that the vehicle stops at the average value of the numbers "N ₅ to _{N 1} " corresponding to the vehicle height when the target value is in the range. Next, when the vehicle height is being controlled to the target value 2, and the target value of the vehicle height changes to 4, the vehicle height raising control is immediately started, which is the reverse of the case described above. . Of course, when controlling the vehicle height to the target value 2, even if the vehicle body vibrates greatly or slightly, the average value of the numbers "N ₅ to _{N 1} " corresponding to the vehicle height sensor will not reach the target vehicle height. It is possible to accurately represent whether the average value is higher or closer than region 2. If the average value is high, the average value approaches "3", and conversely, if the average value is low, the average value approaches "1". Therefore, it is possible to correctly control the target value to 2. As explained above,
According to the present invention, codes (K ₁ to _{K 5} ) corresponding to a plurality of vehicle height regions detected by the vehicle height sensor 3
The present invention can be carried out using a simple configuration in which the value is converted into a numerical value (N ₁ to N ₅ ) corresponding to the height of the vehicle body at each first sampling period, and the average value is determined at each second sampling period. Even when using a vehicle height sensor that detects a large number of vehicle height regions as in the example, there is an effect that the vehicle height can be averaged easily, accurately, and at high speed. Furthermore, the first sampling period is set to a speed that can sufficiently follow the transition of the vehicle height sensor code (K ₁ to _{K 5} ) due to the unsprung resonance frequency of the vehicle body, and the second sampling period is set to a speed that is sufficient to follow the transition of the vehicle height sensor code (K 1 to K 5 ) due to the unsprung resonance frequency of the vehicle body. With a simple configuration of setting the minimum and optimal time for averaging the vibration caused by Even when the vehicle is running, it is possible to determine whether the vehicle height has stopped based on vehicle height information averaged over the same period of time. This has the effect of preventing overshooting due to delays in vehicle height adjustment when stopped, and also prevents unnecessary vehicle height adjustment from starting or stopping due to passenger movement, shaking, or other unnecessary vibrations of the vehicle body. . As explained above, according to the present invention, it is possible to expect the effect of being able to stop the vehicle height based on the situation of the average vehicle height that is averaged over the same period of time regardless of whether the vehicle is stopped or running, and at the same time, it is possible to adjust the vehicle height. This has the effect that the start determination can be easily shortened or extended as necessary. This is the control device 22
Based on the various input information input to This can be easily achieved by increasing or decreasing the number N of references to the average value of the height. If the car is still stopped, the change in car height is mostly due to a change in load, so it is best to use a small value of N to determine whether to start adjusting the car height.On the other hand, if the car is still running, the car height adjustment should be started. The change in height is less due to the change in load.
Since the vibrations of the vehicle are more likely to be the cause, it is sufficient to determine whether to start adjusting the vehicle height using a sufficiently large value of N.
This is based on the information from the vehicle speed sensor 29, and the CPU 4
This can be easily realized by calculating the vehicle speed and changing the value of N according to the calculated value. By the way, starting the vehicle height adjustment as soon as possible while the vehicle is stopped and avoiding unnecessary vehicle height adjustments while driving can be easily achieved using the above example, but it is possible to start the vehicle height adjustment as soon as possible while the vehicle is stopped. If you want to start vehicle height control as quickly as possible, you can set the value of N to the minimum, such as once, but if the value of N is too small, the vibrations of the vehicle due to the movement of the occupants while the vehicle is stopped will increase. In addition, there is a risk that unnecessary vehicle height control may be performed when the vehicle oscillates frequently when the vehicle oscillates and stops due to bonnet specifications inspection, trunk inspection, or frequent oscillation stops due to road stagnation. In this case, the value of N is set to, for example, 3 to 4 times even when the vehicle is stopped, and information on passengers getting on and off is detected by another means, and the value of N is shortened as necessary. By doing so, you can perform ideal vehicle height control in the shortest time when necessary, and do not perform vehicle height control at all when unnecessary. In other words, it is determined from the vehicle height sensor 29, the signal of the key SW51, and the signal of the door SW52. For example, when the vehicle speed is zero and the key SW51 is
When switching from OFF to ON, the above N value is shortened to 1, the start of vehicle height adjustment is brought forward, and when the vehicle height adjustment is completed or the vehicle speed reaches the specified value, the regular N value is changed. For example, when the vehicle speed is zero and the door is opened or closed by the door opening/closing SW 52, the value of N can be shortened again.
The vehicle height adjustment can be started early and controlled to return to the original value as necessary. Also, if the detection code of the vehicle height sensor 3 is outputting K ₂ or K ₁ for more than a predetermined time while the vehicle is stopped, this means that the vehicle height is decreasing due to the load. It is also possible to shorten the value of N to hasten the start of vehicle height adjustment. Directly shortening the value of N using the code output of the vehicle height sensor 3 in this way also has the effect of hastening the start of vehicle height adjustment. By the way, in the above embodiment, the case was described in which the start time of vehicle height adjustment was shortened as necessary, but conversely, in order to prevent unnecessary vehicle height adjustment, the value of N mentioned above may be increased as necessary. However, similar effects can be expected. In other words, the CPU 44 transmits the brake SW 53, the gear position signal 54 of the manual transmission, the automatic range switching signal 55, and the information of the vehicle speed sensor 29.
For example, detecting that the car is moving from a running state to a stop, and increasing the value of N to prevent changes in vehicle height due to forward leaning during braking. For example, when the vehicle is stopped, the manual transmission is shifted, or the automatic transmission range is switched to N, D, R, etc. Needless to say, by increasing the value of N, it is possible to easily prevent unnecessary vehicle height adjustments due to sudden forward or backward tilting of the vehicle. Incidentally, in the above embodiment, a case was described in which the start of vehicle height adjustment is advanced as necessary, and vice versa, a case in which the vehicle height adjustment is prevented. This can be achieved by shortening the value of N in order to hasten the resumption of vehicle height adjustment even if the vehicle height adjustment is interrupted due to insufficient completion. Normally, if you start and end the vehicle height adjustment as soon as possible before stopping, you can set the N value to a sufficiently large value while driving to avoid malfunctions caused by vibrations or turning of the vehicle. If a sudden start is made while the vehicle height is being adjusted, the vehicle height adjustment will be stopped due to vibrations of the vehicle body caused by the start and the shifting of the transmission gear. This is because the average value of the vehicle height at the second sampling time, which is determined by the sprung resonance frequency of the vehicle body, averages out vehicle vibrations (changes in vehicle height) caused by human-controlled gear shifting and acceleration/deceleration. This is because the average value inevitably fluctuates by exceeding the target value or the target value. After the vehicle height adjustment has stopped, the vehicle speed has increased, so the original number of determinations N has been changed to a large value, so there is a drawback that the vehicle height adjustment cannot be restarted easily. According to the present invention, even in such a case, by switching the value of N to an optimal value as necessary, the vehicle height adjustment can be resumed promptly after the vibration of the vehicle body has stabilized. First, if the vehicle height adjustment is started when the vehicle speed is zero, and the vehicle speed increases before it is finished, and the vehicle height adjustment is stopped when the vehicle speed exceeds a predetermined value, whether the vehicle height adjustment was being performed when the vehicle speed was zero or not. , on the other hand, if the temperature is lowered, the CPU44
is stored in the memory 43, and the value of N for the start determination is set to an optimal value that is longer than the cycle of changes in vehicle height due to acceleration and deceleration due to sudden starts or gear changes, but shorter than the normal value of N during driving. Set to . In this way, the vehicle height adjustment is promptly resumed after the gear shift is completed and the vehicle returns to normal running. If the direction of this restarted vehicle height adjustment is the same as the direction stored in the memory 43, the value of N after this control is completed returns to the normal long value of N according to the vehicle speed. You can do it like this. In this way, it is possible to provide a vehicle height adjustment device that can complete vehicle height adjustment in as short a time as possible after the motivation for vehicle height adjustment occurs.
Also, the target value of the vehicle height can be set automatically or manually.
It goes without saying that even when switching from high to low or from low to high using SW, etc., by shortening the value of N, it is possible to hasten the start of vehicle height adjustment. In the above embodiment, the target value of the vehicle height is 2.
Although the case where there are five vehicle height regions has been described in the above, it goes without saying that the same effect can be expected in other cases by setting the numerical values corresponding to the vehicle height regions to appropriate values. Further, although the explanation has been made using means for adjusting the vehicle height using air pressure, it goes without saying that the same effect can be expected by means using hydraulic, mechanical, or other power.

〔Effect of the invention〕

As explained above, according to the present invention, the code output of the vehicle height sensor is read, converted to a desired numerical value,
Average it, memorize it, compare it with the memorized value,
Regardless of the vehicle speed or other information, the end of vehicle height adjustment is determined by whether the above-mentioned average value, rounded to the nearest 5, matches the target or has gone too far, and the vehicle height adjustment is started from the 1st time to the Nth time. It should be carried out only when the average values of are all large or small, and the vehicle speed,
With a simple configuration in which the value of N is changed to the optimal value each time based on IGSW, door SW, gear shift SW, and other driving information, even when using a vehicle height sensor that detects multiple vehicle height regions, It has the effect of being able to provide a vehicle height adjustment device that can easily, accurately and quickly average the vehicle height, and it has the effect of providing an optimal and simple vehicle height adjustment device that does not distinguish between stopped and running conditions. On the contrary, when vehicle height adjustment is necessary, it is possible to provide a vehicle height adjustment device that can prevent unnecessary vehicle height adjustment.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a vehicle height sensor 3 according to an embodiment of the present invention, FIG. 2 is a basic configuration diagram of a suspension 10 that constitutes a vehicle height adjustment mechanism according to an embodiment of the present invention, and FIG. A basic configuration diagram of an embodiment of the present invention, FIG. 4 is an internal configuration diagram of the control circuit 22 in FIG. 3, and FIG. FIG. In addition, in the figure, 3 is a vehicle height sensor, 10 is a suspension, 22 is a control device, 29 is a vehicle speed sensor, and 51
is the power switch, 52 is the door switch, 53 is the brake
SW, 54 is the gear shift signal of the manual transmission, 4
4 is a CPU, and 43 is a memory.

Claims (1)

[Claims] 1. A vehicle height sensor that classifies the height of a vehicle body relative to wheels or axles into a plurality of regions and detects which of the classified regions it belongs to, and a detection signal of this vehicle height sensor is input. , means for sampling at a first sampling period capable of following the resonant frequency of the unsprung portion of the vehicle body, means for converting this sampled detection signal of the vehicle height sensor into a numerical value corresponding to the height of the vehicle body, and means for converting this numerical value into a numerical value corresponding to the height of the vehicle body. 1 sampling time; means for averaging the added value every second sampling time longer than at least one period of the resonance frequency on the spring of the vehicle body; and 4. a storage means for sequentially storing a plurality of decimal values of the average value for each second sampling time; Means to compare the numerical value with the numerical value corresponding to the target position of the vehicle height and start the vehicle height lowering control when all the numerical values from 1 to N times before are large, and after starting the vehicle height lowering control, a means for stopping the vehicle height lowering control when the average value for each second sampling time rounded to the nearest 4 is equal to or falls below the value corresponding to the target vehicle height position; Means for comparing N values from the value N times before with a value corresponding to the target position of the vehicle height, and starting vehicle height raising control when all the values from 1 time to N times before are small. , 4 of the average value for each of the second sampling times mentioned above after starting vehicle height raising control.
A vehicle height adjustment device characterized in that the vehicle height adjustment device is provided with means for stopping vehicle height raising control when the rounded value for the first time matches or exceeds a numerical value corresponding to a target position of the vehicle height. 2. The vehicle height adjustment device according to claim 1, wherein a vehicle speed signal is input and the value of N required for starting the determination can be changed N times according to the vehicle speed. 3. Claim 1, characterized in that the signal of the power key SW is input, and the value of N can be changed when the power is switched from off to on.
The vehicle height adjustment device according to item 1 or 2. 4 When the power is switched from off to on, the above N
4. The vehicle height adjusting device according to claim 3, wherein the value of N is shortened and the value of N is returned to the normal value once vehicle height control is started. 5 When the power is switched from off to on, the above N
4. The vehicle height adjusting device according to claim 3, wherein the value of N is shortened and the value of N is returned to the normal value after the vehicle speed reaches a predetermined value. 6. The vehicle height adjustment device according to claim 1 or 2, which receives a door opening/closing signal as an input and shortens the value of N in accordance with the door opening/closing signal. 7. The vehicle height adjustment device according to claim 1 or 2, which receives a brake signal as an input and changes the value of N when the vehicle stops from a running state. 8. The vehicle height adjustment device according to claim 1 or 2, wherein the value of N is changed according to the transmission gear position and the speed change signal. 9. The vehicle height adjustment device according to claim 1 or 2, wherein the value of N is changed according to a range position signal and a range switching signal of an automatic transmission. 10 If vehicle height control is started while the vehicle is stopped, and vehicle height control is stopped when the vehicle speed exceeds a predetermined value,
Claim 1 or 2, characterized in that the value of N is shortened and then the value of N is returned to a desired value after a predetermined vehicle height control is started. Vehicle height adjustment device. 11. The vehicle height according to claim 1 or 2, wherein there are a plurality of vehicle height target values, and the value of N is shortened in accordance with switching of the vehicle height target values. Adjustment device. 12 A feature is that a specific region of the vehicle height is determined from the detection signal of the vehicle height sensor, a numerical value corresponding to the region of the vehicle height, or its average value, etc., and the value of N is shortened when the vehicle is in that region. A vehicle height adjustment device according to claim 1 or 2.