JPH02299915A - Ground clearance control unit - Google Patents

Abstract

PURPOSE:To prevent the ground clearance of a vehicle from overlowering by decreasing a ground clearance when it exceeds a second upper limit value larger than an upper limit value mentioned below, in the case of adjusting the ground clearance so as to be lower than an appointed upper limit value when an ignition switch is OFF. CONSTITUTION:When an ON-state of an ignition switch is detected by a means M3, a means M1 for adjusting a ground clearance is controlled by a means M4 so that to the ground clearance detected by a means M2 becomes to a ground clearance between an appointed upper and lower limit values. Meanwhile, in a condition of OFF-state of the ignition switch, the means M1 mentioned above is controlled by a means M5 so that the ground clearance becomes lower than the upper limit value during an appointed time elapses. In this case, the means M5 mentioned above judges whether the detected ground clearance exceeds a second upper limit value larger than the limit value mentioned above or not by means of a means M6. And when the detected ground clearance exceeds the second upper limit value, the means M1 mentioned above is controlled by a means M7 so that the ground clearance becomes lower than the second upper limit value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vehicle height control device that suitably executes vehicle height control when the ignition switch is OFF.

[Prior art] Vehicle height control device 1 (top) This device is designed to maintain the vehicle height at a constant level even if the vehicle body load changes due to an increase or decrease in the number of vehicle occupants, etc. It generally detects the vehicle height, The vehicle height is controlled within a predetermined range by lowering the vehicle body when the detected vehicle height exceeds a predetermined upper limit value and raising the vehicle body when the vehicle height falls below a predetermined lower limit value. .

By the way, in order to execute such vehicle height control, 1. Since electric power is required to drive the vehicle height adjustment mechanism that raises or lowers the vehicle body color, vehicle height control is performed even when the engine is stopped and the battery that is the vehicle's power source cannot be charged. , battery power may be consumed and the engine may not start.

Therefore, in the past, as described in Japanese Utility Model Application Publication No. 61-64006, vehicle height control IA when the ignition switch is turned off (i.e., when the engine is stopped) Only during a certain period of time when the vehicle body is likely to be lowered, lowering control that does not require a power source such as a compressor (i.e. low power consumption) is executed, and after a certain period of time has passed after the ignition switch is turned off, such lowering control is executed. It is also being considered that it will be banned.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional device, there is a problem in determining whether to perform vehicle height control after the ignition switch is turned off.

This is done using the same upper limit value as the lowering control of the vehicle body when the ignition switch is turned on, and when the vehicle height exceeds this upper limit value due to passengers getting out of the vehicle, etc., the vehicle body is lowered to control the vehicle height below the upper limit value. Therefore, when the load on the vehicle increases due to passengers boarding the vehicle or loading luggage after the control is completed, 1
: If the vehicle height is too low, in some cases the vehicle body may hit a curb or other protrusion on the road, causing damage to the vehicle body.Therefore, the present invention has been developed.As mentioned above, the vehicle body is lowered after the ignition switch is turned off [Means for solving the problem] In other words, this book was created to achieve the above-mentioned purpose. Invention E
1: As illustrated in FIG.

A vehicle height adjusting means M1 interposed between the vehicle body and the wheels adjusts the vehicle height by raising and lowering the vehicle body; a vehicle height detecting means M2 that detects the vehicle height of the vehicle; and switch state detection means M3 for detecting the open/closed state of the ignition switch.

When the closed state of the ignition switch is detected by the switch state detection means M3, the vehicle height detected by the vehicle height detection means M2 is within a predetermined range determined by a preset upper and lower limit value. When the open state of the ignition switch is detected by the first vehicle height control means M4 that drives the vehicle height adjustment means M1 so as to maintain the vehicle height, and the switch state detection means M3, the following steps are performed until a predetermined period of time elapses. A vehicle height control device comprising: a second vehicle height control means M5 that drives the vehicle height adjustment means M1 so that the vehicle height detected by the vehicle height detection means M2 is equal to or less than a predetermined upper limit value; The second vehicle height control means M5 sets the vehicle height detected by the vehicle height detection means M2 to a second upper limit value set to be at least larger than the upper limit value in the first vehicle height control means M4. and when the vehicle height determining means M6 determines that the vehicle height has exceeded the second upper limit, the vehicle height is determined to be lower than or equal to the second upper limit. The gist of the present invention is a vehicle height control device comprising: control execution means M7 for lowering the vehicle body by driving the vehicle height adjustment means M1.

[Function] In the vehicle height control device of the present invention configured as above (above), when the closed state of the ignition switch is detected by the switch state detection means M3, the first vehicle height control means M4 is activated. Then, the vehicle height adjusting means M1 is driven so that the vehicle height detected by the vehicle height detecting means M2 falls within a predetermined range determined by preset upper and lower limit values.

On the other hand, when the ignition switch is switched to the open state and this is detected by the switch state detection means M3, the second vehicle height control means M5 is activated, and then the r61 ignition switch is opened until a predetermined time elapses. Executes vehicle height control. In addition, when the vehicle height control when the ignition switch is opened (by the companion vehicle height judgment means M 6 When it is determined 1: The vehicle height control execution means M7 drives the vehicle height adjustment means M1 to lower the vehicle body until the vehicle height becomes equal to or less than the second upper limit value, thereby executing the vehicle height control execution means M7.

That is, in the present invention, when the ignition switch is opened, the vehicle body is lowered only when the vehicle height exceeds the second upper limit value, which is larger than the target vehicle height when the ignition switch is closed, due to a decrease in the vehicle load due to occupants getting out of the vehicle, etc. Vehicle height control is executed.

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

First, FIG. 2 is a schematic configuration diagram showing the overall configuration of the vehicle height control device according to the embodiment.

As shown in the figure, the vehicle height control device of this embodiment (air suspensions 2FL, 2FR, and 2RL are installed between the front and rear, left and right wheels of the vehicle and the vehicle body, respectively).

2RR and each of these air suspension 2FL,
2 FR.

The main components include a compressed air supply and discharge system 4 that supplies and discharges air to and from 2 RL and 2 RR, and an electronic control circuit 6 that controls each of these parts. The suffixes FL, FR, RL, and RR+table attached to each air suspension 2 represent the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively, and in the following explanation, the members provided for each of these wheels will be referred to. This subscript will be used for explanation.

Here, each of the above air suspensions 2 FL, 2 F
R.

2 RL, 2 RRIt, variable volume air chambers 10FL, 10FR, 10 that can adjust vehicle height, respectively
R.L., 1. ORR and variable damping force and spring constant shock absorbers 12FL, 12FR, 12RL
, 12RR, and a vehicle height adjustment valve 14FL that communicates and blocks the air passages from the compressed air supply and exhaust system 6 to the air chambers 10FL, 10FR, 10RL, and 10RR, 1
Actuator 16F that switches the damping force and spring constant of 4FR, 14RL, 14RR and shock absorbers 12FL, 12FR, 12RL, 12RR.
It consists of L, 16FR, 16RL, and 16RR.

In addition, a compressed air supply and exhaust system 6 (mountain) includes a compressor with motor 20 that generates the compressed air necessary for raising the vehicle height, a dryer 22 that absorbs moisture from the compressed air, and each air suspension 2 FL and 2 FR when lowering the vehicle height.

2 RL, 2 RR air chamber l0FL,
It includes an air solenoid valve 24 that discharges compressed air from l0FR, 10RL, and l0RR.

Therefore, in this embodiment, 11 air solenoid valve 24
Air suspension 2 FL, 2 F
R.

2 RL, 2 RR vehicle height control valve 14FL,
With 14FR, 14RL, and 14RR in communication, each air chamber 10FL, 10FR, 10RL,
By supplying compressed air from the compressor with motor 20 through the dryer 22 into the 10RR, the vehicle height at each wheel position can be raised, and conversely, the air solenoid valve 24 is in communication and the vehicle height control valve is 14 is in communication, each air chamber l0FL, l0FR
.

By discharging the compressed air in 10RL and 10RR through the air solenoid valve 24, the vehicle height at each wheel position can be lowered.

In addition, the air solenoid valve 24 and the vehicle height control valves 14FL, 14FR, 14R1, 14 of the air suspension 2 FL, 2 FR, 2RL, 2 RR
A normally closed valve is used in the RR (Top), which is normally in a cutoff state and switched to a communication state when energized, and when the control is stopped (A)
0FR, 10RL, and 10RR are in a sealed state. In addition, in this embodiment, Table 1 shows each part for raising or lowering the vehicle height, that is, each air suspension 2FL, 2
Air chamber 10FL in FR, 2RL, 2RR,
10FR.

10RL, l0RR and vehicle height control valve 14FL,
14FR, 14RL, 14RR and the compressed air supply/exhaust system 4 correspond to the vehicle height adjustment means M1 described above.

Next, the electronic control circuit 6 (Table: Air solenoid valve 24 and vehicle height control valves 14FL, 14FR, 14RL).

The CPU 6a, R
It is configured as a well-known logic operation circuit centered on OM6b and RAM6c. 1 table with electronic control circuit 6 Actuators 16FL, 16FR, 16RL, 16R
Drive R to shock absorbers 12FL and 12F.
Control is also executed to switch the damping force and spring constant of R, 12RL, and 12RR, but such control is well known in the art and is not particularly relevant to the present invention, so a description thereof will be omitted.

Additionally, this electronic control circuit 6 includes air solenoid valves 24 and vehicle height control valves 14FL, 14FR, and 14R.
The input circuit is equipped with a drive circuit for driving the L and 14RR, an input circuit ring for inputting detection signals from sensors to be described later for detecting the state of the vehicle, and various circuits for exchanging signals with external devices. Output section 6d and battery 2
A power supply circuit 60 and the like that receive power supply from the control circuit 6 and generate a drive voltage for the control circuit 6 are provided.

One friend is connected to the power line between the power supply circuit 6e and the battery 26.
An ignition switch 28 is provided, and the electronic control circuit 6 is enabled to operate when the ignition switch 28 is turned on, that is, when the engine of the vehicle is running. Also, put the relay switch 30 on the ignition switch 28.

are provided in parallel, and the ignition switch 28
By turning on the relay switch 30 from the electronic control circuit 6 side when the ignition switch 28 is turned on, the electronic control circuit 6 can be self-maintained to be operable even after the ignition switch 28 is turned off.

Next, the vehicle height control device is equipped with a sensor that detects the state of the vehicle, which is installed between the vehicle body and the wheels (specifically, the unsprung members that support the wheels) to adjust the vehicle height at each wheel position. Vehicle height sensor 32 FL as vehicle height detection means M2 for detecting
, 32 FR, 32RL, 32 RRl and,
An ignition sensor 36 is provided as a switch state detection means M3 for detecting the ON/OFF state of the ignition switch 28, and detection signals from these sensors are input to the electronic control circuit 6 via the input/output section 6d. Ru.

In addition, the vehicle height control device (friend) includes each vehicle height sensor 32.
FL, 32 FR, 32RL, 32 RR is equipped with an abnormality indicator light 38 for indicating abnormality. On the electronic control circuit 6 side, each vehicle height sensor 32FL, 32F9 32
R.L.

An abnormality in the sensor is detected based on the output signal from 32RR, and the detection result is sent to the abnormality indicator light 38 via the input/output section 6d.
It is possible to display it on the screen.

Next, each of the vehicle height sensors 32 FL, 32 FR, 3
2RL.

32RRII, as shown in FIG. 3(a), a sensor body 40 and a rotating shaft 40a protruding from the sensor body 40.
It consists of an arm 42 connected to the sensor body 40 and a rod 44 rotatably connected to the tip of the arm 42.
is fixed to the vehicle body side, and the end of the rod 44 opposite to the arm 42 is fixed to an unsprung member such as a suspension arm or a stabilizer, thereby detecting the vehicle height. That is, by doing this, the rod 44 is vertically displaced according to the distance between the vehicle body and the axle (that is, the vehicle height), and this displacement is transmitted to the rotating shaft 40a via the arm 42.
As the rotation shaft 40a rotates, each vehicle height sensor 32FL, 32FR, 32RL, 32RR
(The vehicle height is detected by detecting the rotational position of this rotating shaft 40a on the upper sensor main body 40 side.

In addition, in order to detect the vehicle height in this way, 1:, sensor body 4
As shown in FIG. 3(b), four sets of photocoupler FCI to FC4 are fixed to the rotating shaft 40a,
A slit plate 50 in which a slit is formed to turn each photocoupler FCI to FC4 ON/OFF according to the rotation of the rotating shaft 40a (that is, the vehicle height), and a photocoupler FCI.
- A detection circuit 52 that operates the FC4 to generate a detection signal indicating abnormality of the vehicle height and the sensor.

This detection circuit 52 is constructed as shown in FIG.

As shown in Fig. 4, each of the above photocouplers FCI to FC4
Each of the members is composed of a light-emitting diode DI-D4 and phototransistors Trl to Tr4, and the irradiated light from the light-emitting diode DI-D4 passes through the slit plate 50.
The phototransistor Tr
l=Tr4 becomes OFF state, and conversely, light emitting diode D
When the irradiated light from 1 to D4 passes through the slit formed in the slit plate 50, the phototransistor Trl
=Tr4 becomes ON state.

Therefore, the detection circuit 52 has one light emitting diode DI-0.
4 and the grounding resistors RDEI to RDE4 and R for limiting the current flowing to the phototransistors Tri to Tr4.
TEI-RTE 4 is installed. Light emitting diode DI-D 4 and phototransistor Tr are connected via power supply line.
By applying the battery voltage terminal B to l=Tr4, the light emitting diode DI-04 is caused to emit light, and 1:
, when the phototransistors Tri to Tr4 receive light from the light emitting diode DI-D4 through the slit formed in the slit plate 50, the phototransistor Trl
=A current is allowed to flow through Tr4.

In addition, capacitors CDB and CTB, one end of which is grounded, are connected in series to the power line for applying the battery voltage +B to the light emitting diode DI-D4 and the phototransistor Tr4, respectively. A filter circuit consisting of resistors RDB and RTB is provided to remove superimposed noise components on the power supply line LI.

In addition, the detection circuit 52 receives a load signal LOA from the outside.
In response to D, the signal level (Hi
A well-known shift register SR is provided which takes in a signal (gh.Low) and outputs it while shifting this signal level based on an external clock signal C[OC.

Each phototransistor Tr
The positive electrode side ends of the grounding resistors RTEI to RTE4 of l=Tr4 are connected. Therefore, each of these input terminals P1 to P
4 voltage level (phototransistor Trl”Tr
4 (that is, photocoupler PCI-FC4) is in the ON state and current flows through the grounding resistors RTEI to RTE4, it becomes High level, and conversely, the photocoupler Tr
l to Tr4 are in the OFF state, and the grounding resistor RTEI-
When no current flows through RTE4, the level is 10 yen.

Therefore, the voltage level of each of these input terminals PI-P4 becomes a signal level representing the 0N-OFF state of each photocoupler FCI to FC4, thereby obtaining 4-bit vehicle height data that represents the vehicle height divided into 16 stages. It will be.

In addition, the grounding resistors RDEI, RD of the light emitting diodes DI, DI2, and D3 are connected to the input terminals P5 to P7 of the shift register SR (via buffers 85 to B7 consisting of friend negative circuits).
E'2. The positive electrode side end of RDE3 is connected. Each light emitting diode DI, D2. Since the battery voltage terminal B is always applied to D3, the light emitting diode DI,
D2. When D3 is operating normally (i.e. emitting light), each grounding resistor RDEI, RDE2.R
When current flows through DE3, the voltage level of input terminals P5 to P7 becomes Low level, and conversely, if it is not operating normally (the upper grounding resistors RDEI, RDE2, RDE3
No current flows through the input terminals P5 to P7, and the voltage level at the input terminals P5 to P7 remains the same as the old g.
h level.

Therefore, the voltage level of each input terminal P5 to P7 (the signal level representing the normality or abnormality of the upper light emitting diodes DI, D2, D3) is obtained, thereby obtaining abnormality data representing the abnormality of the sensor.

Grind Three light emitting diodes D out of the four light emitting diodes DI-D4 provided in the sensor in this way 1.
D2. In this embodiment, the photocoupler FC4 having the light emitting diode D4 is assigned as the least significant bit of the 4-bit vehicle height data, and detects whether the light emitting diode D4 is abnormal or not. This is because when this occurs, although the resolution of the detected vehicle height is reduced, the control accuracy in executing the vehicle height control is not significantly reduced.

Next, the input terminal P8 of the shift register SR is connected to the voltage dividing point of the voltage dividing resistors RBB and RBE which divide the voltage of the battery voltage element B through the buffer B8, so that the voltage level of the input terminal P8 is always at the High level. It is designed to be. A capacitor CBB whose one end is grounded is connected to the power line side of the voltage dividing resistor ROB, and a filter circuit is formed by this capacitor CBB and the voltage dividing resistor RBB to eliminate noise on the power line. The ingredients are removed.

In this way, the input terminal p t of the data shift register SR
-p a (upper 4 bits of vehicle height data, abnormality data indicating abnormality of the vehicle height sensor, and steady data that always becomes the old ghL/bel) are input, respectively, so shift register SRI; load signal No. 5 By inputting LOAD and then sequentially inputting clock signal CLOC,
Vehicle height data, abnormal data, and steady data are sequentially output as serial data from the shift register SR.

Therefore, on the electronic control circuit 6 side, each of the above vehicle height sensors 3
2 FL, 32 FR, 32RL, 32 RR
, load signal LO^0 and clock signal CLO
By outputting to C, each vehicle height sensor 32 FL,
By outputting serial data as described above from 32FR, 32RL, and 32RR and reading this data, abnormalities in vehicle height and sensors are detected. In addition, each vehicle height sensor 32 FL, 32 FR, 32RL,
32 8 of the serial data output from RR
th data (steady data) 1 above Since it is always at the old gh level, the electronic control circuit 6 side determines whether or not this data is at the old gh level.
Each vehicle height sensor 32 FL, 32 FR, 32RL,
32 RR and electronic control circuit 6 to detect a disconnection of the signal line. In other words, the above-mentioned steady data is used as data for detecting disconnection of the signal line. When this data reaches a low level, which is normally impossible, it indicates that the signal line between the sensor control circuits is disconnected and the data from the sensor cannot be used. It is to judge.

Next, the vehicle height control process executed in the electronic control circuit 6 to control the vehicle height will be explained based on the flowcharts shown in FIGS. 5 to 7. Electronic control circuit 61 table
The ignition switch 28 is turned on, and the power supply circuit 6e receives power from the battery 26 and generates a drive voltage, thereby starting the vehicle.After starting, the relay switch 30 is turned on'', and then vehicle height control processing is executed.

As shown in FIG. 5, when the vehicle height control process is started, step 110 is first executed, and each of the vehicle height sensors 32 F
Whether or not the vehicle height data obtained by L, 32 FR, 32 RL, 32 RR is normal, that is, each vehicle height sensor 32 FL, 32 FR, 32 RL, 32
Based on the output data from RR, each sensor's light emitting diode DI, D2. Determine whether D3 is operating normally and whether its signal line is disconnected. In step 110, each vehicle height sensor 32
FL.

When it is determined that an abnormality has occurred in 32FR, 32RL, and 32RR, the process moves to step 120, and the abnormality indicator lamp 38 is turned on in accordance with the result of this determination. Then, in step 130, it is determined whether or not vehicle height control is currently being executed by the process described below.
After proceeding to step 140 and executing a vehicle height control stop process to stop the vehicle height control currently being executed, the process is temporarily terminated. do.

Meanwhile, in step 110, each vehicle height sensor 32 FL.

If it is determined that 32 FR, 32 RL, and 32 RR are normal, the process moves to step 150, and it is determined whether the ignition switch 28 is in the ON state. Then, when the ignition switch 28 is in the ON state (step 160), a timer T used to measure the elapsed time after the ignition switch 28 is turned OFF is cleared in a process described later, and the next step 17
At step 0, a flag FON indicating the ON state of the ignition switch 28 is set, and at subsequent step 180,
The vehicle height is controlled when the ignition switch 28 is in the ON state (hereinafter, this state is referred to as lG10N).

The above-described first vehicle height control means M4 executes the vehicle height control process at the time of l GloN, and ends the process once.

Meanwhile, in step 150, the ignition switch 28
If it is determined that the ignition switch 28h is not in the ON state, the process moves to step 190 and checks whether the flag FON is set, that is, if the ignition switch 28h<ON
It is determined whether or not the ignition switch 28 has just been turned from ON to OFF.

Then, in step 190, if it is determined that the flag FON has been set and that the ignition switch 28h has just been switched from ON to OFF, the process moves to the following step 200, otherwise lf, the step described below. 240.

Next, in step 200, lG10N of step 180
Based on the operation of the vehicle height control process, it is determined whether or not vehicle height control is currently being executed. After executing the process, the process moves to step 220, and if vehicle height control is not currently being executed, the process moves to step 2201.Then, the process moves to step 220.
(Top) When the ignition switch 28 is in the ON state, a timer T that is reset in step 160 is started to start measuring the elapsed time after the ignition switch 28 is turned OFF, and in the subsequent step 230, the flag FO is
After resetting N, the process moves to step 240.

In step 240, it is determined whether the value of the timer T, that is, the elapsed time T after the ignition switch 28 is turned off, is less than or equal to a preset predetermined time TI (for example, 3 minutes). If T≦TI, lf, the process moves to step 250, and the ignition switch 28 is turned off (hereinafter, this state is referred to as lG10FF).
Controls the vehicle height when the vehicle is in the

The above-described second vehicle height control means M5 executes the vehicle height control process at the time of lGloFF, temporarily ends the process, and conversely returns to T.
>TI (Dai) By turning off the ONL and relay switch 30 at startup, the power supply to the electronic control circuit 6 is cut off.

That is, after the ignition switch 28 is turned off, the vehicle height control is executed until a predetermined time TI elapses, and after the predetermined time TI elapses, the relay switch 30 is turned off to stop the vehicle height control. At the same time, the operation of the electronic control circuit 6 prevents battery power from being consumed.

1GloN vehicle height control process executed in step 180 here. t, the vehicle height on the left front wheel side, the vehicle height on the right front wheel side, and the average vehicle height on the rear wheel side are each controlled to be within preset target ranges, thereby maintaining the vehicle body posture in a predetermined state. As shown in FIG. 6(a), first in step 181 it is determined whether or not vehicle height control is currently being executed. Ranking (1 friend in this example: Front left wheel - Front right wheel -
step]82. Step 183. Step 184
), on the other hand, if the vehicle height control is already being executed (Table 1), step 185 and step 186 determine whether vehicle height control is being executed on the left front wheel, right front wheel, or rear wheel.
), and the vehicle height control process is shifted to the vehicle height control process on the wheel side where the vehicle height control is being executed.

As will be explained in detail later, in the vehicle height control process on each wheel side executed in steps 182 to 184 (Table 1), when the vehicle height control on the corresponding wheel side is executed ( Since the vehicle height control process is terminated at the time of GloN, the process from step 182 to step 183 or from step 183 to step 1 is performed.
Transition to 84 (friend) is performed only when vehicle height control is not actually executed on the left front axle (111L) or on the right front wheel side.

Next, the vehicle height control processing at each wheel side executed in steps 182 to 184 will be explained. Since the contents are the same, here we will take vehicle height control on the left front wheel (FL) as an example, and
This will be explained along the flowchart shown in Figure (b).

As shown in FIG. 6(b), when the vehicle height control process for the left front wheel during lGloN is started, first step 30
Based on the detection data from the vehicle height sensor 32F at 0,
The vehicle height S at the left front axle position is detected, and the process moves to step 310. Step 3] Climb control execution flag F that is set when the vehicle body lift control is started in the subsequent processing
Based on the OP, it is determined whether or not the vehicle body lift control is currently being executed on the left front wheel side. And rise control execution flag F
If the UP is in the reset state and the vehicle body lift control is not being executed (if the UP is in the reset state), proceed to the following step 320
It is determined whether the vehicle height S detected in step 300 has fallen below the ascending control start vehicle height S IJPS representing the lower limit value of the vehicle height that is the control target.

In the second step 320, the vehicle height S starts raising control.
If it is determined that the
, the compressor with motor 20 is driven to generate compressed air, and the vehicle height control valve 1 on the left front axle side is activated.
By energizing 4FL and bringing the valve surface into communication state,
Lifting control for lifting the vehicle body on the left front axle side is started, and the process moves to the following step 340, where a lifting control execution flag F is set.

In this way, in step 340, the ascending control execution flag FO
P is set, or if it is determined in step 310 that the ascending control execution flag FOP has already been set (upper step 350, step 300
The vehicle height S detected at the vehicle height S detected at the end of the vehicle height S UPS is set to be slightly larger than the vehicle height S UPS at the end of the vehicle height control.
Determine whether the limit has been exceeded. And this step 350
If it is determined that the vehicle height S is equal to or less than the vehicle height S IJPE at which the raising control ends, the IGloN vehicle height control process is immediately terminated in order to continue raising the vehicle height on the left front wheel side.

On the other hand, at step 350, the vehicle height S is changed to the vehicle height S at which the raising control is completed.
If it is determined that the DPE has been exceeded, the condition for terminating the vehicle height control for the left front wheel is satisfied, and the process proceeds to step 360 to stop driving the compressor with motor 20 and energizing the vehicle height control valve 14FL. After completing the lift control and resetting the lift control execution flag FUP in the subsequent step 370, the process proceeds to step 183, which is a right front axle side vehicle height control process.

Next, in step 320, if it is determined that the vehicle height S is greater than or equal to the vehicle height at which the raising control starts, step 38
0, and it is determined whether or not the lowering control of the vehicle body is currently being executed on the left front wheel side based on the lowering control execution flag F out which is set when the lowering control of the vehicle body is started in the subsequent processing. Then, if the lowering control execution flag F DWI is in the reset state and lowering control of the vehicle body is not being executed, the process proceeds to step 390, and the vehicle height S detected in step 300 is the vehicle height that becomes the control target. If vehicle height S does not exceed processing control start vehicle height sowst, the conditions for executing vehicle height control on the left front axle side are met. It is determined that there is no vehicle, and the process proceeds to step 183, which is a right front wheel side vehicle height control process.

On the other hand, in step 390, the vehicle height S starts lowering control.
If it is determined that DWS+ has been exceeded, the process proceeds to step 400, where the left front wheel side vehicle height control valve 14F [and the air solenoid valve 24 are energized to communicate with both valves, thereby controlling the left front wheel side vehicle height control valve 14F [and air solenoid valve 24]. A descending control for lowering is started, and the process proceeds to step 410, where a descending control execution flag FDWI is set.

In this way, in step 410, the descending control execution flag FD
If WI is set, or if it is determined in step 380 that the descending control execution flag F DWI has already been set, the process moves to step 420, and the vehicle height Starting vehicle height 5DWS
Descending control road set to a value slightly smaller than I° Finished vehicle height 5
Determine whether the value has fallen below the DWEI. Then, in this step 420, the vehicle height S is changed to 5DWEI, which is the end vehicle height of the lowering control.
If it is determined that this is the case, the IGloN vehicle height control process is immediately terminated in order to continue lowering the vehicle height on the left front wheel side.

On the other hand, at step 420, the vehicle height S is lowered to the vehicle height 5 at which the lowering control ends.
If it is determined that the vehicle height has fallen below the DWEI, it is assumed that the conditions for terminating the vehicle height control for the left front wheel have been met, and the process moves to step 430, where the power supply to the vehicle height control valve 14F [and the air solenoid valve 24 is stopped, and the vehicle height control valve 14F and the air solenoid valve 24 are stopped. The lowering control is ended by turning off the valve, and after the lowering control execution flag FDWI is reset in the subsequent step 440, the process proceeds to the right front axle side vehicle height control process in step 183.

Next, the IGloFF vehicle height control process executed in step 250 described above will be described.

This lGloFF vehicle height control processing table 1 Left front wheel side vehicle height,
This process executes vehicle body lowering control so that the average vehicle height of the right front entry side and the rear axle side are respectively below the preset upper limit vehicle height. Similarly, as shown in FIG. 7(a), first step 251
Step 252: determines whether vehicle height control is currently being executed, and if vehicle height control is not being executed, executes vehicle height control processing on each wheel side according to preset priorities; Step 253. step 254)
Conversely, if the vehicle height control is already being executed (Table 1), it is determined whether the vehicle height control is being executed on the left front wheel, right front wheel, or rear wheel (steps 255 and 256), and the vehicle height control is This procedure is executed by moving to vehicle height control processing on the wheel side where the control is being executed.

Also, in this lGloFF time vehicle height control process, in the vehicle height control process on each axle side executed in steps 252 to 254, [1] If vehicle height control is being executed on the corresponding axle side, Since the vehicle height control processing at the time of IG10FF is terminated as it is, the vehicle height is actually adjusted from step 252 to step 253 or from step 253 to step 254. Occurs only when control is not running.

The vehicle height control process on each wheel side executed in steps 182 to 184 will be described below.
Similar to the GloN vehicle height control process, vehicle height control on the left front wheel side (FL) will be explained using the flowchart shown in FIG. 7(b) as an example.

As shown in FIG. 7(b), when this lGloFF vehicle height control process is started, first in step 500, the vehicle height S at the left front axle position is detected based on the detection data from the vehicle height sensor 32FL. , the process moves to step 510. In step 510 (above), the lGloFF control execution flag F DW2, which is set when the lowering control at lGloFF is started in the subsequent processing, causes lGloFF to be applied to the left front wheel.
It is determined whether or not the time lowering control is being executed. Then, if the IGIOFF time control execution flag FDW2 is in the reset state and the descending control during lGloFF is not executed (Friend), the process proceeds to step 520, and the vehicle height S detected in step 500 indicates that the descending control during lGloN is not executed. lGl set to a thicker value than the starting vehicle height 5DWSI
Determine whether the vehicle height S exceeds control start vehicle height S DWS2 when oFF, and control start vehicle height S DWS when vehicle height S is lGloFF.
2 is less than or equal to [f, it is determined that the conditions for executing the vehicle height control on the left front axle side are not satisfied, and the process proceeds to step 253, which is the vehicle height control process on the right front axle side.

On the other hand, if it is determined in step 520 that the vehicle height S exceeds lG10F F-time control start vehicle height S DWS2, step 530 is performed and the vehicle height control valve 14FL on the left front wheel side is
By energizing the air solenoid valve 24 and bringing both valves into communication, the lowering control for lowering the vehicle body on the left front wheel side is started, and the process moves to the subsequent step 540 where the lG
Set loFF control execution flag F DW2.

In this way, in step 540, the descending control execution flag F
If DW2 is set, or if it is determined in step 510 that the lowering control execution flag FDWlh<already set, the process moves to step 550, and the vehicle height S detected in step 300 is determined as I G10F F Time control start vehicle height S is set to a value slightly smaller than DWS2.
It is determined whether the vehicle height at the end of GloFF control has fallen below SDWE2. Then, in this step 550, the vehicle height s
If it is determined that the control end vehicle height S DWE: 2 or more at G10FF in h month, the vehicle height remains at lG to continue descending control.
The loFF vehicle height control process ends.

On the other hand, if it is determined in step 550 that the vehicle height S has fallen below the vehicle height 5DWE2 at which the control ends at lGloFF, it is assumed that the condition for terminating the vehicle height control on the left front wheel side is satisfied, and the process proceeds to step 560, in which the vehicle height The control valve 14F and the air solenoid valve 24 are de-energized to turn both valves into a cutoff state, thereby ending the descending control at the time of lGloFF, and in the subsequent step 560, the control execution flag FDW2 at the time of lGloFF is reset. The process then proceeds to right side vehicle height control processing in step 253.

As explained above, in the vehicle height control device of this embodiment (
Table When the ignition switch 28 is in the ON state, the vehicle height control process is executed when the vehicle is in the 10N state. This l
GloN vehicle height control process (top left front, right front) For each rear wheel position, as shown in FIG.
When ps is lowered, the vehicle body is raised until the vehicle height S becomes equal to or higher than the vehicle height 5UPE at which the raising control ends, and at time t2 the vehicle height S reaches the upper limit of the control target. When the vehicle height S exceeds 5DWE, the vehicle body is lowered until the vehicle height S becomes lower than 5DWE 1, the end of the lowering control.
Because it is executed in the following procedure, the vehicle height at each wheel position at 1G10N is SI.
The vehicle body posture is maintained within a predetermined range determined by the lowering control start vehicle height 5DWSI and the lowering control start vehicle height 5DWSI.

Next, as shown in FIG. 8, when the ignition switch 28 is switched from ON to OFF at time t3, the vehicle height control process at 1G10FF is executed until a predetermined time TI has elapsed. In this lGloFF vehicle height control process, the same as the lGloN vehicle height control process. When the vehicle height S at which control starts at '1G10FF exceeds DIIIS2, the vehicle body is lowered until the vehicle height S becomes equal to or less than the vehicle height at which control ends at 1GloFF 5DWE2. In addition, the control start vehicle height S DWS2 and the control end vehicle height S DWE21t at lGloFF, the downward control start vehicle height sowst and the downward control end vehicle height S DW at lGloN.
It is set to a value larger than EI. For this reason lGlo
Even if the vehicle body load increases, for example at time t5, after the vehicle height control during FF is completed, the vehicle height will not drop significantly.

In other words, with conventional equipment, 1. t, target vehicle height when executing vehicle height control at IC10FF lGloFF of this embodiment
Since it was the same as the vehicle height at which descent control started at the time of 1GloN, as shown by the dotted line in Fig. 8, after 1G10FF, the vehicle load decreased due to passengers getting off the vehicle, If the height increases, the vehicle body will be lowered to the target vehicle height at lGloN, and then when the vehicle load increases due to passengers getting on, etc., the vehicle height will drop significantly and the vehicle body may run onto a curb, etc. However, in this embodiment, the control start vehicle height at l G10F F is l Gl
Since this value is set to a value larger than the vehicle height at which the descending control starts at the time of oN, the vehicle body is
The vehicle is not lowered at the height at which the lowering control starts at loN, and the vehicle height can be prevented from being significantly lowered when the vehicle load increases after the control ends, and the vehicle body can be protected from curb stones and the like.

In addition, in this way, the control start vehicle height at lGloFF is set to lGl
Setting the vehicle height to a value larger than the lowering control start vehicle height at the time of ON reduces the frequency of execution of the vehicle height control at the time of IGloFF, which also has the effect of suppressing power consumption of the battery 26.

On the other hand, in this embodiment, the vehicle height sensor used to detect the vehicle height has vehicle height data, light emitting diodes DI, D2. D
Since it is configured to sequentially output the abnormal data representing the abnormality of No. 3 and the steady data that is always at the old gh level as serial data, the signal line for transmitting the detected data can be reduced to one, which is different from the conventional The number of signal lines between sensor control circuits can be reduced compared to the case of using a more commonly used vehicle height sensor that outputs each detection data in parallel.

In addition, since steady data is output from the vehicle height sensor, if the signal line between the sensor control circuits is disconnected, the electronic control circuit 6 will detect this and perform incorrect vehicle height control. can be prevented.

In the above example, when lt lGloN and lGloFF
Regarding the vehicle height control processing performed on each wheel side during the vehicle height control processing at the time, we have explained the vehicle height control on the left front axle side as an example, and explained that the same applies to the other wheel sides. When executing vehicle height control processing to control the average vehicle height at When actually raising or lowering the
Of course, the vehicle height control valves 14RL and 14RR for the left and right rear wheels are driven at the same time.

[Effects of the Invention] As explained above, 1: In the vehicle height subwriting device of the present invention, the vehicle height is larger than the upper limit of the target vehicle height used in executing the vehicle height control when the ignition switch is closed. When the second upper limit set in the value is exceeded 1:,
Since vehicle height control is executed when the ignition switch is open, it is possible to suppress the vehicle height from dropping significantly when the vehicle body load increases after the vehicle height control is completed when the ignition switch is open. can be protected from protrusions on the road surface such as curbstones. Additionally, since vehicle height control when the ignition switch is open is not executed until the vehicle height exceeds the second upper limit, the upper limit when the ignition switch is closed is used as is to determine whether to start vehicle height control after the ignition switch is opened. Compared to conventional devices, the frequency of vehicle height control performed when the ignition switch is open is reduced, and power consumption when the ignition switch is open can also be suppressed.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the configuration of the present invention. FIG. 2 is a schematic diagram showing the overall configuration of a vehicle height control device according to an embodiment. FIG. 3 is a block diagram illustrating the configuration of a vehicle height sensor. FIG. 5 is a flowchart showing the vehicle height control process executed by the electronic control circuit; FIG. 6 is the vehicle height at lGloN executed at step 180 in FIG. FIG. 7 is a flowchart explaining the vehicle height control process at the time of lGloFF executed in step 250 of FIG. 5. FIG. 8 is a flowchart explaining the operation of the vehicle height control process of the embodiment. be. Ml...Vehicle height adjustment means M2...Vehicle height detection means M
3... Switch state detection means M4... First vehicle height control means M5... Second vehicle height control means

Claims (1)

[Scope of Claims] Vehicle height adjustment means that is interposed between the vehicle body and wheels and adjusts the vehicle height of the vehicle by raising and lowering the vehicle body; and vehicle height detection means that detects the vehicle height of the vehicle. , a switch state detection means for detecting an open/closed state of an ignition switch of the vehicle; and when the closed state of the ignition switch is detected by the switch state detection means, the vehicle height detected by the vehicle height detection means is determined in advance. a first vehicle height control means that drives the vehicle height adjustment means so that the vehicle height is within a predetermined range determined by set upper and lower limit values; and an open state of the ignition switch is determined by the switch state detection means. When the vehicle height is detected, a second controller drives the vehicle height adjusting means so that the vehicle height detected by the vehicle height detecting means is equal to or less than a predetermined upper limit value until a predetermined period of time elapses thereafter.
A vehicle height control device comprising a vehicle height control means, wherein the second vehicle height control means is such that the vehicle height detected by the vehicle height detection means is at least the upper limit of the first vehicle height control means. a vehicle height determining means for determining whether or not the vehicle height exceeds a second upper limit set to a value greater than the vehicle height; A vehicle height control device comprising: control execution means for lowering the vehicle body by driving the vehicle height adjustment means until the height becomes equal to or less than a second upper limit value.