JP2019051829A - Vehicle height control system and down control method - Google Patents

Abstract

To decrease noise emitted when a compressor is started.SOLUTION: In a vehicle height control system, after the pressure of a pressure medium on a discharge side of a compressor is made higher than the pressure of a pressure medium on an intake side, the compressor is started. In a case where the pressure of the pressure medium on the discharge side of the compressor is higher than the pressure of the pressure medium on the intake side when electric current supplied to an electric motor that drives the compressor is switched from OFF to ON, load applied on the compressor in its start increases. Consequently, the compressor is made less likely to rotate in its start, so that the number of rotations of the compressor in its start is decreased or the start of the compressor is delayed. As a result, noise emitted in the start of the compressor can be decreased.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a closed type vehicle height control system and a down control method for performing down control to lower the vehicle height in a closed type vehicle height control system.

  In the closed type vehicle height control system described in Patent Document 1, when down control is performed to lower the vehicle height, the suction side portion of the compressor is communicated with the air cylinder, and the discharge side portion is communicated with the tank. And the compressor is started. By the operation of the compressor, air is sucked from the air cylinder and stored in the tank, thereby lowering the vehicle height.

JP, 2006-175573, A

  An object of the present invention is to reduce the sound generated when the compressor is started.

Means and effects for solving the problem

In the vehicle height control system according to the present invention, the compressor is started after the pressure of the pressure medium on the discharge side of the compressor is higher than the pressure of the pressure medium on the suction side.
When the supply current to the electric motor that drives the compressor is switched from OFF to ON, a large start-up current flows through the compressor. Therefore, when the supply current to the electric motor is switched from OFF to ON, if the pressure medium pressure on the suction side portion and the pressure medium pressure on the discharge side portion of the compressor are substantially the same, The load (resistance) applied to the compressor is small, and the compressor is suddenly rotated at a large rotational speed. Thereby, a loud sound is generated.
On the other hand, if the pressure medium pressure on the discharge side of the compressor is higher than the pressure medium pressure on the suction side when the supply current to the electric motor is switched from OFF to ON, The load to be increased. At the start, the compressor is difficult to rotate, and the rotation speed of the compressor is reduced or the start of the compressor is delayed. As a result, the sound generated when the compressor is started can be reduced.

Further, in the down control method according to the present invention, after the preparatory step of communicating the compressor suction side portion with the low pressure portion and the compressor discharge side portion with the high pressure portion is performed, The control valve is opened, the compressor is started, and the down process is executed.
Thus, the suction side portion of the compressor is communicated with the low pressure portion, and the discharge side portion of the compressor is communicated with the high pressure portion, so that the pressure medium pressure of the suction side portion is changed from the pressure medium pressure of the compressor discharge side portion. The differential pressure minus the pressure increases. That is, the differential pressure is increased by the execution of the preparatory process as compared to before the preparatory process is performed. Therefore, the sound generated when the compressor is started can be reduced by executing the preparation process. At the start of the preparation step, the pressure of the pressure medium in the high pressure part is usually higher than the pressure medium in the low pressure part, but it is not always higher than the pressure medium in the discharge side part. Further, the pressure medium in the low pressure part is usually lower than the pressure medium in the suction side part.

It is a circuit diagram showing the vehicle height control system which concerns on this invention. In the vehicle height control system, the down control method according to the present invention is implemented. It is a conceptual diagram showing the periphery of vehicle height control ECU of the said vehicle height control system. It is a figure showing the state before the start of a compressor in the said vehicle height control system. It is a figure showing the state at the time of the starting of the said compressor. It is a flowchart showing the down control program memorize | stored in the memory | storage part of the said vehicle height control ECU. It is a flowchart showing the start time control program memorize | stored in the said memory | storage part.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a vehicle height control system according to an embodiment of the present invention will be described in detail with reference to the drawings. In this vehicle height control system, the down control method which is one embodiment of the present invention is implemented.
In the vehicle height control system, air is used as the pressure medium.

In the present vehicle height control system, as shown in FIG. 1, wheel side members (for example, suspension arms that support the wheels, etc.) and the vehicle body correspond to each of the front, rear, left and right wheels provided in the vehicle. Between the side members, suspension springs (not shown), air cylinders 2FL, FR, RL, RR as vehicle height control actuators, and shock absorbers 4FL, FR, RL, RR are provided in parallel with each other. Each of the shock absorbers 4FL, FR, RL, RR includes an absorber main body provided on the wheel side member and an absorber piston provided on the vehicle body side member.
Hereinafter, in the present specification, when it is necessary to distinguish between the air cylinder 2, the shock absorber 4 and the like by the position of the wheel, symbols FL, FR, RL, and RR indicating the position of the wheel are attached. When there is no need to distinguish between them, the symbols FL, FR, RL, RR, etc., which represent the position of the wheel, are omitted in describing the generic name.

  Each of the air cylinders 2 is provided on a cylinder main body 10 provided on a vehicle body side member, a diaphragm 12 fixed to the cylinder main body 10, and an absorber main body of the diaphragm 12 and the shock absorber 2 so as not to be relatively movable in the vertical direction. The air piston 14 is included, and the inside thereof is an air chamber 19 as a pressure medium chamber. The air piston 14 is moved relative to the cylinder body 10 in the vertical direction by supplying and discharging air in the air chamber 19, whereby the absorber body and the absorber piston are relatively moved in the vertical direction in the shock absorber 4. The vehicle height, which is the distance between the wheel side member and the vehicle body side member, is changed.

  An air supply / discharge device 24 is connected to the air chamber 19 of the air cylinder 2 via an individual passage 20 and a common passage 22, respectively. Each individual passage 20 is provided with a vehicle height control valve 26. The vehicle height control valve 26 is a normally closed electromagnetic valve that is opened and closed by turning the solenoid on and off. The vehicle height control valve 26 allows bidirectional air flow in the open state and blocks air flow from the air chamber 19 to the common passage 22 in the closed state. When the pressure becomes higher than the set pressure by 19 or more, the air flow from the common passage 22 to the air chamber 19 is allowed.

The air supply / discharge device 24 as a pressure medium supply / discharge device includes a compressor device 30, an exhaust valve 32 that is a normally closed electromagnetic valve, a tank 34, a switching device 36, an intake valve 44, a relief valve 46, and the like.
The compressor device 30 includes a compressor 40 and an electric motor 42 that drives the compressor 40, and the compressor 40 is operated by driving the electric motor 42. In this embodiment, the compressor 40 is a plunger pump and includes a suction valve 41a and a discharge valve 41b. The suction valve 41a and the discharge valve 41b allow the flow of air from the suction side to the discharge side of the compressor 40 but prevent the reverse flow. Further, when the discharge pressure of the compressor 40 increases, the air is exhausted to the atmosphere through the relief valve 46.
The tank 34 accommodates air in a pressurized state, and when the amount of air accommodated increases, the tank pressure, which is the pressure of the accommodated air, increases.

The switching device 36 includes a common passage 22, a tank passage 48 connected to the tank 34, a suction passage 65 connected to the suction side portion 40a of the compressor 40, and a discharge passage connected to the discharge side portion 40b of the compressor 40. The first passage 50, the second passage 52, and the circuit valves 61 to 64 are provided.
As shown in FIG. 1, the common passage 22 and the tank passage 48 to which the tank 34 is connected are connected by a first passage 50 and a second passage 52 provided in parallel to each other, Two circuit valves 61 and 62 are provided in series, and two circuit valves 63 and 64 are provided in series in the second passage 52. Further, the portion between the two circuit valves 61 and 62 of the first passage 50 and the intake side portion 40a of the compressor 40 are connected by the suction passage 65, and the discharge side portion 40b of the compressor 40 is connected by the discharge passage 66. The portion of the second passage 52 between the two circuit valves 63 and 64 is connected.

The circuit valves 61 to 64 are normally closed electromagnetic valves, which are switched between an open state and a closed state by ON / OFF of the solenoid. A current is supplied to the solenoid, and the solenoid is opened by being turned on. Allow bidirectional air flow in the open state. A current is not supplied to the solenoid, and the solenoid is closed by being turned off. In the closed state (solenoid OFF state), the flow of air from one side to the other side is blocked, but if the pressure on the other side is higher than the pressure on one side by more than the set pressure, one from the other side Allow air flow to the side.
The circuit valves 61 and 63 prevent the outflow of air from the tank 34 in the closed state, and the circuit valve 62 prevents the outflow of air from the common passage 22 in the closed state. Reference numeral 64 denotes a supply of air to the common passage 22 in the closed state.

An intake valve 44 is provided between the connection portion 65s of the intake passage 65 and the atmosphere. The intake valve 44 is a check valve that is closed when the air pressure at the connecting portion 65s is equal to or higher than the atmospheric pressure, and is opened when the pressure is lower than the atmospheric pressure. When the pressure of the air at the connection portion 65 s becomes lower than the atmospheric pressure by the operation of the compressor 40, the air is sucked from the atmosphere through the filter 43 and the intake valve 44.
The exhaust valve 32 is connected to the connection portion 66 s of the discharge passage 66. The exhaust valve 32 is a normally closed solenoid valve, and in the open state, discharge of air from the discharge passage 66 to the atmosphere is permitted, and in the closed state, discharge of air from the discharge passage 66 to the atmosphere is prevented. When the pressure of the air in the discharge passage 66 becomes lower than the set pressure by the atmospheric pressure, the supply of air from the atmosphere to the discharge passage 66 is permitted.
Further, a dryer 70 and a flow suppressing mechanism 72 are provided in series at a portion closer to the second passage than the connection portion 66 s of the discharge passage 66. The flow suppressing mechanism 72 includes a differential pressure valve 72v and a throttle 72s provided in parallel with each other. The differential pressure valve 72v blocks the flow of air from the second passage side to the compressor side. When the pressure on the compressor side becomes higher than the pressure on the second passage side by a set pressure or more, the air pressure from the compressor 40 to the second passage 52 is reduced. Allow flow.

  In the present embodiment, the vehicle height control system is controlled by a vehicle height control ECU 80 mainly including a vehicle height control computer. The vehicle height control ECU 80 can communicate with another ECU or the like via a CAN (Controller Area Network) 82. As shown in FIG. 2, the vehicle height control ECU 80 includes an execution unit 80c, a storage unit 80m, an input / output unit 80i, a timer 80t, and the like. The input / output unit 80i includes a vehicle height changeover switch 88, a tank pressure sensor 90, The passage pressure sensor 91, the vehicle height sensor 93, the getting-on / off related motion detection device 95, and the like are connected, and the communication device 96, the ignition switch 98, the vehicle speed sensor 99, and the like are connected via the CAN 82. In addition, the electric motor 42 is connected via the drive circuit 100, and the exhaust valve 32, the vehicle height control valve 26, and the circuit valves 61 to 64 are connected.

The vehicle height changeover switch 88 is operated by the driver and is operated when the vehicle height is instructed to be changed to any one of L (Low), N (Normal), and H (High). . The tank pressure sensor 90 detects the tank pressure, and the passage pressure sensor 91 is provided in the common passage 22 and corresponds to the vehicle height control valve 26 that is open when the vehicle height control valve 26 is opened ( Cylinder pressure, which is the pressure of the air chamber 19 of the cylinder 2 (corresponding to the wheel) is detected. Further, the passage pressure, which is the pressure of air in the common passage 22, is detected when all the vehicle height control valves 26 are closed. The vehicle height sensor 93 is provided for each of the front, rear, left, and right wheels, and detects the vehicle height that is the distance from the wheel side member of the vehicle body side member. The getting-on / off-related operation detecting device 95 detects the presence / absence of an action related to getting on / off, and is provided corresponding to each of a plurality of doors provided in the vehicle, and detects a door opening / closing sensor ( A courtesy lamp sensor) 102, a door lock sensor 103 for detecting the lock and unlock of each of the plurality of doors, and the like. Based on the presence / absence of door opening / closing, door locking / unlocking operations, etc., the intention of getting on, getting off, or starting is estimated. The communication device 96 communicates with the portable device 104 possessed by the driver or the like within a predetermined communicable area, and the door may be locked or unlocked by communication. . The ignition switch 98 is a vehicle main switch. The vehicle speed sensor 99 detects a traveling speed of the vehicle.
In addition, the vehicle height control system and the like in the present embodiment can be operated by the power of the battery 110. The voltage of the battery 110 is detected by the voltage monitor 112, and the voltage monitor 112 is connected to the vehicle height control ECU 80.

  In the vehicle height control system configured as described above, when down control, which is vehicle height control for lowering the vehicle height, is performed, the circuit valves 62 and 63 are opened as shown in FIG. 40 is started, and the vehicle height control valve 26 of the wheel to be controlled is opened. Air is sucked from the air cylinder 2 by the compressor 40, pressurized, and supplied to the tank 34. Air is exhausted from the air cylinder 2 and the vehicle height is lowered.

However, when the supply current to the electric motor 42 is switched from OFF to ON, a large starting current flows through the compressor 40. Further, before the down control is started, the air pressure on the suction side 40a of the compressor 40 and the air pressure on the discharge side 40b are often substantially the same.
Therefore, when the compressor 40 is started, the load applied to the compressor 40 is small, and the compressor 40 is suddenly rotated at a large rotational speed. Therefore, a large vibration is generated and a loud sound is generated.

On the other hand, in this embodiment, before the supply current to the electric motor 42 is switched from OFF to ON, the circuit valves 62 and 63 are opened as shown in FIG. Maintained for a while. The common passage 22 is communicated with the suction passage 65 via a part of the first passage 50, and the tank passage 48 is communicated with the discharge passage 66 via a part of the second passage 52. When the down control start command is output, the air pressure in the common passage 22 is usually lower than the air pressure in the suction passage 65. Further, the suction valve 41 a and the discharge valve 41 b provided in the compressor 40 block the flow of air from the discharge passage 66 toward the suction passage 65. As a result, the state shown in FIG. 3 results in an increase in the differential pressure, which is a value obtained by subtracting the air pressure in the suction passage 65 from the air pressure in the discharge passage 66, and the air pressure in the discharge passage 66 is sucked. It becomes higher than the air pressure in the passage 65.
Further, since this state is maintained for the set time, the air pressure in the discharge passage 66 of the compressor 40 becomes higher than the set pressure by the air pressure in the suction passage 65, and the load applied to the compressor 40 at the time of starting is large. Become.

Note that the set value is set to a value that can increase the load applied to the compressor 40 at the start and reduce the rotation speed of the compressor 40, and the set time is such that the air pressure in the discharge passage 66 is low in the suction passage 65. It can be set to a time determined based on the time required to become higher than the set value by the air pressure.
Thereafter, as shown in FIG. 4, the vehicle height control valve 26 of the wheel to be controlled is opened, the compressor 40 is started, and the down control is started.

The down control program represented by the flowchart in FIG. 5 is executed at predetermined time intervals.
In step 1 (hereinafter abbreviated as S1. The same applies to other steps), the vehicle height is detected by the vehicle height sensor 93, and in S2, it is determined whether down control is being performed. If the down control is not being performed, it is determined in S3 whether or not a start condition for the down control is satisfied. For example, if the actual vehicle height, which is the actual vehicle height detected in S1 with respect to the target vehicle height, is greater than or equal to the start threshold value, it is determined that the start condition for down control is satisfied. If the determination is NO, S1 to S3 are repeatedly executed. If the start condition is satisfied and the determination is YES, a down control start command is output in S4.

In response to the start command, the start time control represented by the flowchart of FIG. 6 is performed.
In S11, the circuit valves 62 and 63 are opened, and in S12, it is determined whether or not a set time has elapsed. When the set time has elapsed, in S13, the compressor 40 is started and the vehicle height control valve 26 corresponding to the wheel to be controlled is opened.
The air in the air cylinder 2 of the wheel to be controlled is sucked by the compressor 40 and supplied to the tank 34, and the down control is started.

  When the down control is started, the determination at S2 is YES, and at S5, it is determined whether or not the down control end condition is satisfied. The end condition is assumed to be satisfied, for example, when the difference between the target vehicle height and the actual vehicle height is equal to or less than an end threshold value determined based on a dead zone or the like. If the determination is NO, the down control is continued, but if the end condition is satisfied, the down control end command is output in S6. In accordance with the end command, end time control (not shown) is performed. In this embodiment, the circuit valves 62 and 63 are closed, the vehicle height control valve 26 is closed, and the compressor 40 is stopped. In addition, before the compressor 40 is stopped, control for reducing the pressure difference between the suction side portion 40a and the discharge side portion 40b of the compressor 40 may be performed. Thereby, the sound generated when the compressor 40 is stopped can be suppressed.

  As described above, in this embodiment, the air pressure in the discharge passage 66 of the compressor 40 is made higher than the air pressure in the suction passage 65 before the compressor 40 is started. As a result, the load applied to the compressor 40 at the time of starting increases, and the rotational speed at the time of starting the compressor 40 decreases or the starting is delayed. As a result, vibration generated when the compressor 40 is started can be suppressed, and the generated sound can be reduced. In the vehicle height control system according to this embodiment, the sound intensity (sound pressure level: dB) generated when the compressor 40 is started is approximately 10% lower than in the conventional vehicle height control system. It was confirmed that

As described above, in the present embodiment, the start time control unit is configured by the part for storing the start time control program represented by the flowchart of FIG. 6 of the vehicle height control ECU 80, the part for executing, and the like. The solenoid valve control unit is configured by the parts to be performed.
Further, the execution of S11 corresponds to the preparation process, and the execution of S13 corresponds to the down process.

  It should be noted that the structure of the vehicle height control system is not limited to the above-described embodiments. For example, the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art in addition to the aspects described above. it can.

  2: Air cylinder 24: Air supply / discharge device 26: Vehicle height control valve 30: Compressor device 32: Exhaust valve 34: Tank 40: Compressor 48: Tank passage 50: First passage 52: Second passage 65: Suction passage 66: Discharge passages 61-64: Circuit valve 80: Vehicle height control ECU 90: Tank pressure sensor 91: Passage pressure sensor 93: Vehicle height sensor

Claims (3)

A plurality of vehicle height control actuators respectively provided on a plurality of wheels of the vehicle;
A pressure medium supply / discharge device connected to the plurality of vehicle height control actuators, comprising: (a) a compressor; and (b) a tank for storing a pressure medium pressurized by the compressor.
By operating the compressor, the vehicle height control actuator corresponding to the wheel to be controlled among the plurality of wheels is discharged from the vehicle height control actuator and supplied to the tank, so that the vehicle height of the wheel to be controlled is lowered. In a vehicle height control system including a vehicle height control unit that performs down control that is control,
The vehicle height control unit includes a vehicle height control unit including a start time control unit that makes the pressure medium pressure on the discharge side of the compressor higher than the pressure medium pressure on the suction side of the compressor before starting the compressor. system. The plurality of vehicle height control actuators are connected to a common passage;
The pressure medium supply / discharge device includes a plurality of solenoid valves, the common passage, a tank passage connected to the tank, a discharge passage connected to a discharge side portion of the compressor, and a suction side portion of the compressor Including a switching device that is provided between the suction passages connected to each other and capable of switching a communication state between them,
2. The vehicle height control according to claim 1, wherein the start-up control unit includes an electromagnetic valve control unit that communicates the suction passage with the common passage and communicates the discharge passage with the tank passage under the control of the switching device. system. A plurality of vehicle height control actuators provided respectively on a plurality of wheels of the vehicle and connected to a common passage via a vehicle height control valve;
(a) a tank storing air, (b) a compressor, (c) a tank passage connected to the tank, a suction passage connected to a suction side portion of the compressor, and a discharge side portion of the compressor Vehicle height including a pressure medium supply / discharge device including a connected discharge passage and a plurality of solenoid valves provided between the common passage and a switching device capable of switching a communication state therebetween. In the control system, down control that lowers the vehicle height of the wheel to be controlled by discharging the pressure medium from the vehicle height control actuator of the wheel to be controlled among the plurality of vehicle height control actuators and supplying the pressure medium to the tank. A method,
By controlling the switching device, the suction passage is blocked from the tank passage and communicated with the common passage, and the discharge passage is blocked from the common passage and communicated with the tank passage;
A down control method including opening a vehicle height control valve of the wheel to be controlled and starting the compressor.

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