JPH0364322B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronically controlled suspension device that reduces posture changes that occur when a selector lever is operated in a vehicle equipped with an automatic transmission.

[Technical background of the invention and its problems] In a vehicle equipped with an automatic transmission, especially when the selector lever is moved from the neutral (N) position to the drive (D) position with the handbrake pulled. Another problem was that the rear part of the car body lowered due to the reaction force of the torque, and conversely, when the selector lever was moved from drive (D) to neutral (N), the rear part of the car body rose, making the occupants feel uncomfortable.

[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to reduce the change in the posture of the vehicle body that occurs when the selector lever is changed in a vehicle equipped with an automatic transmission. The objective is to provide an electronically controlled suspension device that can

[Summary of the invention] A fluid spring chamber provided between a wheel and a vehicle body;
a fluid supply/discharge device for controlling the supply and discharge of fluid in the fluid spring chamber; a position detection means for detecting the position of the automatic transmission; and a position detected by the position detection means for changing the position from a non-travel position to a travel position. , or when it is detected that the vehicle has been operated from the driving position to the non-driving position, a biasing force is applied to the fluid spring chamber to offset the change in attitude of the vehicle body caused by the operation after a set delay time from the time of detection. The suspension device is equipped with a control means for performing attitude control to control the fluid supply and discharge device to cause the above-mentioned fluid supply/discharge device to perform attitude control. The average vehicle height within a later setting determination time is determined from the detection signal of the vehicle height sensor, and the setting delay time is corrected in a direction in which the average vehicle height approaches a reference vehicle height based on the average vehicle height. This is an electronically controlled suspension device.

[Embodiment of the Invention] An electronically controlled suspension device according to an embodiment of the present invention will be described below with reference to the drawings.
In Figure 1, the air suspension unit
Since FS1, FS2, RS1, and RS2 each have almost the same structure, the air suspension unit will be explained below using the symbol S, unless the front and rear units are specifically explained. However, only the parts necessary for vehicle height control will be illustrated and explained.

That is, the air suspension unit S incorporates a shock absorber 1, and this shock absorber 1 includes a cylinder attached to the front wheel or the rear wheel side, and a piston slidably inserted into the cylinder. Since the cylinder moves up and down relative to the piston rod 2 in accordance with the up and down movement of the wheel, shock can be effectively absorbed and the damping force changes in accordance with the stroke of the wheel.

By the way, an air spring chamber 3 which also serves as a vehicle height adjustment fluid chamber is disposed coaxially with the piston rod 2 at the upper part of the shock absorber 1. A bellows 4 is formed in a part of the air spring chamber 3. Therefore, the passage 2 provided in the piston rod 2
By supplying and discharging air to the air spring chamber 3 via a,
It is designed to allow the piston rod to move up and down.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 5a facing upward, and the outer wall of the air spring chamber 3 is provided with a spring receiver 5b facing downward.
are formed, and a coil spring 6 is loaded between these spring receivers 5a and 5b.

Thus, 11 is a compressor. This compressor 11 compresses the atmospheric air sent from the air cleaner 12 and supplies it to the dryer 13 . The compressed air dried with silica gel or the like from the dryer 13 is transferred to the reserve tank 15 via the check valve 14 . It is stored in the high pressure side reserve tank 15a. This reserve tank 1
5 is provided with a low pressure side reserve tank 15b. A compressor 16 driven by a compressor relay 17 is provided between the reserve tanks 15a and 15b. Further, a pressure switch 18 is provided which is turned on when the pressure in the low pressure side reserve tank 15b becomes equal to or higher than atmospheric pressure.
When the pressure switch 18 is turned on, the compressor relay 17 is driven. As a result, the reserve tank 15b is always kept below atmospheric pressure. The route by which compressed air is supplied from the high-pressure side reserve tank 15a to the suspension unit S is indicated by a solid arrow. That is, the compressed air from the reserve tank 15a is supplied to the air supply flow control valve (CV) 19, the front air supply valve (F.Sup) 20, the check valve 21,
Front right solenoid valve (FR) 22,
The front right suspension unit is connected to the front right suspension unit via the front left solenoid valve (FL) 23.
FS2, front left suspension unit
Sent to FS1. Similarly, the compressed air from the reserve tank 15a is supplied to the air supply flow control valve 19, the rear air supply valve (R.Sup) 24, the check valve 25, the rear right solenoid valve (RR) 26, and the rear left air solenoid valve (RR) 26. Solenoid valve (RL)
Rear right suspension unit via 27
RS2, rear left suspension unit RS1
sent to. On the other hand, the exhaust passage from the suspension unit S is indicated by a broken line arrow. In other words,
Front suspension unit FS1, FS2
Exhaust air is sent to the low pressure side reserve tank 15b via solenoid valves 22, 23 and a front exhaust valve (F.Ex) 28, and is also sent to the discharge side of the dryer 13 via a check valve 29. Further, exhaust gas from the rear suspension units RS1 and RS2 is sent to the low pressure side reserve tank 15b via the solenoid valves 26, 27 and the rear exhaust valve (R.Ex) 30, and is also sent via the check valve 31 to the It is sent to the discharge side of the dryer 13. Incidentally, an exhaust passage consisting of an exhaust solenoid valve 32 and a check valve 33 is provided between the air cleaner 12 and the dryer 13 in parallel with the compressor 11, and the compressed air is discharged through the dryer 13 in the direction of the dashed arrow. Air is released to the atmosphere via this exhaust solenoid valve (A.Ex) 32, check valve 33, and air cleaner 12.

Further, 34 is a vehicle height sensor, and this vehicle height sensor 3
Reference numeral 4 denotes a front vehicle height sensor 34F that is attached to the lower arm 35 of the suspension on the front right side of the vehicle and detects the front vehicle height of the vehicle, and a front vehicle height sensor 34F that is attached to the lateral rod 36 of the suspension on the rear left side of the vehicle and detects the front vehicle height of the vehicle. The vehicle includes a rear vehicle height sensor 34R for detecting vehicle height, and detection signals are supplied from these vehicle height sensors 34F and 34R to a control unit 37 serving as a vehicle height adjustment control section.

Each sensor 34F, 34 in the vehicle height sensor 34
R is designed to detect the distance from the normal vehicle height level, the low vehicle height level, or the high vehicle height level, respectively.

Furthermore, the speedometer has a built-in vehicle height sensor 38, which detects the vehicle speed and transmits the detection signal to the control unit 3.
7.

Further, an acceleration sensor 39 is provided as a vehicle body posture sensor that detects changes in the posture of the vehicle body.
This acceleration sensor 39 is designed to detect changes in the pitch, roll, and yaw of the vehicle on its springs. For example, when there is no acceleration, the weight is in a hanging state, and the light from the light emitting diode is directed toward the shielding plate. By blocking the light from reaching the photodiode, the absence of acceleration is detected. When acceleration acts in the front and back, left and right, or up and down directions, the weight tilts or moves, and the acceleration state of the vehicle body is detected.

Reference numeral 40 denotes an indicator for displaying oil pressure, and the display of this indicator 40 is controlled by the control unit 37. A steering sensor 41 detects the rotational speed of the steering wheel 42, that is, the steering speed, and its detection signal is sent to the control unit 37. Furthermore, 4
Reference numeral 3 denotes an accelerator opening sensor (not shown) for detecting the depression angle of an accelerator pedal of the engine, and its detection signal is sent to the control unit 37. Further, 44 is a compressor relay for driving the compressor 11, and this compressor relay 44 is controlled by a control signal from the control unit 37. Furthermore, 45 is a pressure switch that is turned on when the pressure in the reserve tank 15a falls below a predetermined value, and its output signal is output to the control unit 37. That is, when the pressure in the reserve tank 15a falls below a predetermined value, the pressure switch 45 is turned on, and the compressor relay 45 is operated under the control of the control unit 37. As a result, the compressor 11 is driven to feed compressed air into the reserve tank 15a, and the pressure inside the reserve tank 15a is raised to a predetermined value or higher. 46 is the air spring chamber 3 of the rear suspension units RS1 and RS2.
This is a pressure sensor that detects the pressure in the air spring chambers 3 of the rear suspension units RS1 and RS2, which are provided in the communication passages that communicate with the rear suspension units RS1 and RS2. This pressure sensor 4
The pressure signal detected at 6 is output to the control unit 37.

Further, 47 is a parking brake switch (PSW), the operation signal of which is output to the control unit 37. Further, 48 is a brake switch (BSW), the operation signal of which is output to the control unit 37. Furthermore, 4
An A/T switch 9 outputs a signal corresponding to the position of the selector lever of the automatic transmission, and the signal is output to the control unit 37.

Note that the solenoid valves 22, 23, 2
6, 27, 32 and valves 19, 20, 24, 2
Opening/closing control of 8 and 30 is performed by control signals from the control unit 37. The solenoid valves 22, 23, 26, and 27 are three-way valves, and their two states are shown in FIG. FIG. 2A shows a state in which the three-way valve is driven, and in this state compressed air moves along the path indicated by arrow A. On the other hand, FIG. 2B shows a state in which the three-way valve is not driven, and in this state compressed air moves along the path indicated by arrow B. Further, the valves 19, 20, 24, 28, 30 and the solenoid valve 32 are two-way valves, and the two
The two states are shown in FIG. FIG. 3A shows a state in which the solenoid valve is driven, and in this state compressed air moves in the direction of arrow C. On the other hand, when the solenoid valve is not driven, the situation is as shown in FIG. 3B, and in this case, there is no flow of compressed air.

Furthermore, the configuration of the air supply flow rate control valve 19 is shown in FIG. FIG. 4A shows a state in which the solenoid valve is activated, and in this state compressed air moves in the direction of arrow C through the small diameter orifice 50. Therefore, the amount of compressed air that moves is small. On the other hand, when the solenoid valve is not driven, the state becomes as shown in FIG. Much more than time.

Next, the operation of the present invention configured as described above will be explained. The processing in the flowchart shown in FIG. 5 is performed by the control unit 37, and the details of the processing will be explained below. First, it is detected by the state of the brake switch 48 whether the main brake, that is, the foot brake, is off (not depressed).
S1). If it is determined that the foot brake is not depressed, it is determined whether the vehicle speed is "0", that is, the vehicle is stopped, based on the vehicle speed signal output from the vehicle speed sensor 38 to the control unit 37 (step S2). Here, if it is determined that the vehicle is stopped, the process advances to step S3. In this step S3, when it is determined that the handbrake, that is, the PSW 47 is on (that is, the handbrake is pulled), the A/T determines from which position the selector lever has been moved to which position by the determination in steps S4 to S7. The determination is made based on the switch 49. Here, if it is detected that the selector lever has been moved from neutral (N) to drive (D), the flag N in the control unit 37 is set to "1" (step
S8). Furthermore, the selector lever is in reverse (R)
If it is detected that the position has been moved from to neutral (N), the flag N in the control unit 37 is set to ``2'' (step S9).
When it is detected that the selector lever has been moved from neutral (N) to reverse (R), a flag N is set in the control unit 37.
is set to "3" (step S10). Also,
When it is detected that the selector lever has been moved from drive (D) to neutral (N), "4" is set in the flag N in the control unit 37.
is set (step S11). Next, the delay time T(N) corresponding to the flag N stored in the delay time memory in the control unit 37 is
is continued (step S12). That is, the attitude control is started after the selector lever is shifted by a delay time T(N) shown in FIG. 7B. This is because there is a delay between when the selector lever is shifted and when the attitude changes, so the time to start attitude control must also be delayed. Then, the control time Tc (N) corresponding to the flag N for controlling the opening and closing of the valve stored in the control time memory in the control unit 37 is determined (step S14). Next, the value of flag N is determined (step S15). Here, if flag N is "1" or "2", that is, if the selector lever is shifted from neutral (N) to drive (D), or if the selector lever is shifted from reverse (R) to neutral (N) Since the rear wheels are about to go down, control to raise the rear wheels is performed at step S16. In other words, the valve marked "○" in the "Rear Up" mode that raises the rear wheels in the vehicle height adjustment mode in the valve opening/closing table in Figure 6 is turned on for the time Tc (N) as shown in Figure 7B. suspension unit RS1,
Compressed air from the reserve tank 15a is fed into the air spring chamber 3 of the RS2. For this reason, Figure 7C
The vehicle height of the rear wheels increases as shown in . And t
A vehicle height averaging unit time DT (for example, 0.05 seconds) is set (step S17). On the other hand, when flag N is "3" or "4", that is, when the selector lever is shifted from neutral (N) to reverse (R), or when the selector lever is shifted from drive (D) to neutral (N), Since the rear wheels tend to rise, control to lower the rear wheels is performed at step S18. In other words, the valve marked "○" in the "Rear Down" mode that lowers the rear wheels in the vehicle height adjustment mode in the valve opening/closing table in Figure 6 is turned on for a time Tc (N) as shown in Figure 7B. suspension unit RS1,
The compressed air in the air spring chamber 3 of RS2 is released to the atmosphere. Therefore, the vehicle height of the rear wheels decreases. Then, -DT is set to t (step S19).
By the way, when the process of step S17 or step S19 is completed, T(N) is set to Tb (step S20), and the control time Tc(N) is set to Tb (step S20).
After completion, the output of the vehicle height sensor 34 is continued to the control unit 37 for 0.45 seconds (step
S21). Then, the average vehicle height for 0.45 seconds is calculated (step S22). It is determined whether the vehicle height average value calculated in this way is a standard vehicle height (normal vehicle height) (step S23). Here, if the vehicle height average value is the standard vehicle height, the process returns to step S1. On the other hand, if the average vehicle height is not the standard vehicle height, it is determined whether the average vehicle height is lower than the standard vehicle height (step S24). Here, if it is determined that the vehicle height average value is lower than the standard vehicle height, "Tb-t" is set to Tb. In other words, in order to improve the fact that the attitude control executed was too slow in response to the attitude change of the vehicle body caused by the lever operation, the delay time T
(N) is shortened by t time (0.05 seconds). By shortening the delay time T(N) in this way,
The time for starting attitude control after the selector lever is shifted is brought forward so that the next attitude control is executed at an effective timing with respect to the attitude change caused by the lever operation.
Then, Tb is set to T(N) (step
S26), the process returns to step S1 above. On the other hand, if the average vehicle height is determined to be higher than the standard vehicle height,
"Tb-t" is set to Tb (step S27).
In other words, in order to correct the fact that the attitude control executed was too slow in response to changes in the attitude of the vehicle body caused by lever operation, the above delay time T(N) is set to t time (0.05 seconds).
only lengthened. By increasing the delay time T(N) in this way, the time from when the selector lever is shifted to when attitude control starts is delayed, so that the next attitude control will be more responsive to attitude changes caused by lever operation. This allows for more effective timing.

By the way, if you want to start the car with the handbrake lowered, select "NO" in step S3 above.
It is determined that this is the case, and the processing from step S28 onward is performed. In other words, control (return control) that is the opposite of the posture control in step S16 or S18 is performed. Here, if the flag N is set to "1", a control opposite to that performed in step S16 is performed (step S29). In other words, the valve marked "○" in the "Rear Down" mode that lowers the rear wheels in the vehicle height adjustment mode in the valve opening/closing table in Figure 6 is Tc1.
It is opened for a certain amount of time and the vehicle height on the rear wheel side is lowered.
On the other hand, if the flag N is set to "3" (step S30), the control performed in the above step S18 is reversed (step S29). In other words, the valve marked "○" in the "Rear Up" mode that raises the rear wheels in the vehicle height adjustment mode in the valve opening/closing table in Figure 6 is opened for Tc3 hours to raise the vehicle height on the rear wheels (step S31). ). In this way,
When the handbrake is released and the car starts, control is performed to restore the attitude control performed in step S16 or S18. Then, the flag N is returned to "0" and the process returns to step S1. Thereafter, when the car stops and the direction in which the selector lever is shifted changes, a corresponding value is set in the flag N, and the above-described processing is performed.

By the way, by performing the process of correcting the delay time as in steps S25 and S26 above, the optimum delay time T can be determined while this process is performed several times.
It has a learning function that allows it to be set to (N).

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reduce the change in the posture of the vehicle body that occurs when the selector lever is changed while the vehicle is stopped in a vehicle equipped with an automatic transmission. In particular, it is possible to provide an electronically controlled suspension device that can correct the timing of posture control to be optimal using a learning function.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an electronically controlled suspension device according to an embodiment of the present invention, Fig. 2 A and B
Figure 3A and B are diagrams showing the opening and closing of the solenoid valve. Figure 4 A and B are diagrams showing the opening and closing of the three-way valve.
5 is a flowchart for explaining the operation of one embodiment; FIG. 6 is a diagram showing opening and closing of the valve during attitude control and vehicle height adjustment; and FIG. The figure is a timing diagram for explaining the operation of one embodiment. 15a, 15b... Reserve tank, 19...
Air intake flow control valve, 20... Front air intake valve, 24... Rear air intake valve, 28... Front exhaust valve, 30... Rear exhaust valve,
37... Control unit, 46... Parking brake switch, 47... Brake switch, 48... A/T switch.

Claims (1)

[Claims] 1. A fluid spring chamber provided between a wheel and a vehicle body, a fluid supply/discharge device for controlling supply and discharge of fluid in the fluid spring chamber, and a position detection means for detecting the position of an automatic transmission;
When it is detected that the position detected by the position detecting means has been operated from a non-traveling position to a traveling position, or from a traveling position to a non-traveling position, the position detected by the position detecting means is detected as being caused by the operation after a set delay time from the time of detection. and control means for executing posture control that controls the fluid supply and discharge device to generate a biasing force in the fluid spring chamber that offsets changes in the posture of the vehicle body that occur due to changes in the posture of the vehicle body. The control means is provided with a height sensor, and the control means calculates the average vehicle height within the set determination time after executing the attitude control from the detection signal of the vehicle height sensor, and based on the average vehicle height, the average vehicle height is a reference. An electronically controlled suspension device characterized in that the set delay time is corrected in a direction approaching the vehicle height.