JP6160836B2 - Control device for shock absorber with variable damping force - Google Patents

Description

  The present invention relates to a damping force variable shock absorber, and more particularly to a damping force variable shock absorber control device.

  In a shock absorber with variable damping force of a vehicle such as an automobile, the damping force control valve is driven by an actuator, and the opening amount of the damping force control valve is changed according to the control position of the actuator, whereby the damping coefficient is changed. This controls the damping force. The control position of the actuator is controlled by a control signal supplied to the actuator being controlled by the control device in accordance with the traveling state of the vehicle. Even when the vehicle is stopped, the control signal is controlled by the control device, so that the actuator is positioned at a preset standby position so that the attenuation coefficient becomes an optimum value in the stopped state.

  The damping coefficient of the damping force variable shock absorber is controlled to a low value in situations where it is necessary to ensure good riding comfort of the vehicle, and is set to a high value in situations where it is necessary to ensure steering stability of the vehicle. Be controlled. For example, as described in Patent Document 1 below, when the vehicle speed is less than or equal to a reference value, the damping coefficient is controlled to a high value, thereby reducing squats when starting the vehicle and dives when braking the vehicle. To be done.

JP-A-8-2230

[Problems to be Solved by the Invention]
In vehicles such as automobiles, in order to improve fuel efficiency and reduce exhaust emissions, it is practical to stop the engine by idling stop when the vehicle speed drops below a predetermined value. When idling stop is executed, the engine speed is reduced and the engine is stopped, so that the power supplied from the alternator driven by the engine is reduced to zero.

  Therefore, in a vehicle in which the control signal to the actuator is generated using electric power supplied from the alternator, when idling stop is executed, the actuator is caused by a decrease in the strength (voltage and / or current) of the control signal. In some cases, the control position cannot be controlled to the standby position. In such a situation, a situation in which the control position of the actuator commanded by the control device and the actual control position of the actuator do not coincide, that is, “step out” occurs.

  The present invention has been made in view of the problem that a step-out occurs in the control of a shock absorber when idling stop is executed in a vehicle in which a control signal to an actuator is generated using electric power supplied from an alternator. Is. The main object of the present invention is to prevent step-out from occurring in the control of the shock absorber even when idling stop is executed.

[Means for Solving the Problems and Effects of the Invention]
According to the present invention, when the vehicle speed falls below the stop reference value, the engine control device that stops the engine by idling stop, the alternator that generates power by being driven by the engine, and the damping force control valve is driven to change the damping coefficient. It is mounted on a vehicle having a damping force variable shock absorber equipped with an actuator for generating a control signal using electric power supplied from an alternator, and the damping coefficient is controlled by controlling the control position of the actuator by the control signal. In the control device for the variable damping force shock absorber to be controlled, the shock absorber control device determines the probability that the idling stop is executed, and when it is determined that the execution probability is high, the shock absorber control device is directed to a preset standby position. Start switching the control position of the actuator Control device for the damping force control shock absorber, characterized in that to complete the switching to the standby position before the idling stop is performed is provided.

  According to the above configuration, when it is determined that the probability that the idling stop is executed is high, the control position of the actuator is switched so that the switching to the standby position is completed before the idling stop is executed. Therefore, it is possible to prevent the control position of the actuator from being switched after the engine speed is reduced due to idling stop and the power supplied from the alternator starts to decrease. Therefore, the control position of the actuator cannot be controlled to the standby position due to a decrease in the intensity of the control signal generated using the power supplied from the alternator, preventing the step-out from occurring in the control of the shock absorber. can do.

  In the above configuration, the control device for the shock absorber holds the control position of the actuator at the standby position until it is determined that the idling stop is released or the probability that the idling stop is released is high. It's okay.

  According to the above configuration, the control position of the actuator is held at the standby position until it is determined that the idling stop is released or the probability that the idling stop is released is high. Therefore, the actuator control position is held at the standby position until it is determined that the idling stop is released or the idling stop is released after it is determined that the idling stop is likely to be executed. can do. Therefore, the step-out is caused by switching the control position of the actuator between the time when it is determined that the idling stop is likely to be executed and the time when the idling stop is released or the probability is determined to be high. Occurrence can be prevented.

  In the above configuration, the actuator may be a stepping motor type actuator.

  In the stepping motor type actuator, switching of the control position is achieved by sequentially changing the rotation angle of the stepping motor step by step. Therefore, as compared with the case of the linear solenoid actuator, the time required for switching the control position becomes longer, so that the step-out easily occurs when the idling stop is executed.

  However, according to the configuration of the present invention, the control position of the actuator is switched so that the switch to the standby position is completed before the idling stop is executed. Therefore, even when the actuator is a stepping motor type actuator, the control position of the actuator cannot be controlled to the standby position due to a decrease in the strength of the control signal, and there is an effect that the step-out occurs in the control of the shock absorber. Can be prevented.

  In the above configuration, the shock absorber control device starts switching the control position of the actuator to the standby position when it is determined that the vehicle speed has fallen below the control start reference value higher than the stop reference value. It may be.

  According to the above configuration, when it is determined that the vehicle speed has fallen below the control start reference value higher than the stop reference value, switching of the control position of the actuator to the standby position is started. Then, the control position of the actuator is switched so that the switching to the standby position is completed before the vehicle speed falls below the stop reference value. Therefore, the control start reference value is set to a value that can complete the switching to the standby position before the vehicle speed drops below the stop reference value regardless of the control position of the actuator and the vehicle speed reduction rate.

  In the above configuration, the control start reference value may be variably set according to the vehicle speed decrease rate so that the control speed reference value increases as the vehicle speed decrease rate increases.

  The time until the vehicle speed decreases from a certain value to the stop reference value or less becomes shorter as the rate of decrease in vehicle speed increases, in other words, as the vehicle deceleration increases. Therefore, it is preferable that the switching of the control position of the actuator to the standby position is started earlier as the decrease rate of the vehicle speed is larger so that the switching to the standby position is completed before the vehicle speed falls below the stop reference value. .

  According to the above configuration, the control start reference value decreases as the vehicle speed decrease rate decreases, and conversely increases as the vehicle speed decrease rate increases. Therefore, in the situation where the rate of decrease in vehicle speed is small, the start and completion of switching of the control position of the actuator is prevented from becoming too early, and in the situation where the rate of decrease in vehicle speed is large, the start and completion of switching of the control position of the actuator Can be prevented from becoming too slow.

  In the above configuration, the actuator may be a linear solenoid actuator.

  When the actuator is a linear solenoid actuator, the control position can be changed substantially instantaneously. According to the above configuration, since the actuator is a linear solenoid type actuator, when it is determined that there is a high probability that the idling stop is executed, the standby is performed immediately after the control position is switched to the standby position. The switch to position can be completed.

  In the above configuration, the engine control device transmits an idling stop warning signal to the shock absorber control device when the vehicle speed falls below the warning reference value higher than the stop reference value, and the shock absorber control device When the idling stop notice signal is received, switching of the control position of the actuator to the standby position may be started.

  According to the above configuration, the shock absorber control device receives the idling stop warning signal when the vehicle speed falls below the warning reference value higher than the stop reference value, and switches the control position of the actuator to the standby position. Start. Therefore, immediately after the shock absorber control device receives the idling stop notice signal, the switching of the control position to the standby position can be completed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows 1st embodiment of the control apparatus of the damping force variable shock absorber by this invention applied to the stepping motor type damping force variable shock absorber. It is a graph which shows the damping force characteristic of the damping force variable shock absorber of 1st embodiment. It is a flowchart which shows the attenuation coefficient control routine in 1st embodiment. It is a time chart which shows the action | operation of the control apparatus of 1st embodiment compared with the case of the conventional control apparatus about the condition where a vehicle speed falls gradually and a vehicle stops. It is a flowchart which shows the principal part of the damping coefficient control routine in 2nd embodiment of the control apparatus of the damping force variable shock absorber by this invention applied to the stepping motor type damping force variable shock absorber. It is a map for calculating the reference value Vw0 based on the vehicle deceleration Gxb. It is a time chart which shows the action | operation of a control apparatus when the deceleration Gxb of a vehicle is low about the case where the reference value Vw0 is a constant value. It is a time chart which shows the action | operation of the control apparatus of 2nd embodiment when the deceleration Gxb of a vehicle is low. It is a schematic block diagram which shows 3rd embodiment of the control apparatus of the damping force variable shock absorber by this invention applied to the linear solenoid type damping force variable shock absorber. It is a graph which shows the damping force characteristic of the damping force variable shock absorber of 3rd embodiment. It is a flowchart which shows the attenuation coefficient control routine in 3rd embodiment. It is a time chart which shows the action | operation of the control apparatus of 3rd embodiment about the condition where a vehicle speed falls gradually and a vehicle stops.

  Hereinafter, some preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First embodiment]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a control device 10 for a variable damping force shock absorber according to the present invention applied to a stepping motor variable damping force shock absorber.

  In FIG. 1, a control device 10 is mounted on a vehicle 12 and controls a damping force variable shock absorber 14 provided corresponding to each wheel not shown in the figure. The vehicle 12 includes an engine 16 and an alternator 18 that generates electric power when driven by the engine. The engine 16 is controlled by the engine control device 20 based on the accelerator opening and the like. In particular, when it is determined that the vehicle 12 has stopped, the engine control device 20 stops the engine 16 by idling stop, and when it is determined that the vehicle 12 resumes running, the engine control device 20 cancels the idling stop and restarts the operation of the engine 16.

  The shock absorber 14 has a cylinder 22 and a piston 24 that is fitted to the cylinder so as to be able to reciprocate relatively. The cylinder 22 and the piston 24 cooperate with each other to form a cylinder upper chamber 26 and a cylinder lower chamber 28. Is forming. The cylinder upper chamber 26 and the cylinder lower chamber 28 are filled with oil as a working liquid. In the illustrated embodiment, the cylinder 22 is connected to a suspension member 32 such as a wheel carrier or a suspension arm via an attachment device 30 at the lower end.

  The piston 24 has a piston main body 24A and a rod portion 24B integrated with the piston main body 24A at the lower end, and the rod portion 24B extends upward through the upper end of the cylinder 22. A damping force control valve 34 that variably controls the damping force in the compression stroke and the extension stroke is provided in the piston main body 24A. The rod portion 24B is connected to the vehicle body 38 of the vehicle 12 via the upper support 36 at the upper end. A rotary actuator 42 incorporating a stepping motor 40 is connected to the upper end of the rod portion 24B.

  The stepping motor 40 can take a plurality of rotational positions. The stepping motor 40 controls the valve body of the damping force control valve 34 to a plurality of rotational positions via the control rod 44, thereby changing the valve opening amount of the damping force control valve 34 in multiple stages. Therefore, the actuator 42 changes the execution passage cross-sectional area of the communication path connecting the cylinder upper chamber 26 and the cylinder lower chamber 28 in multiple stages, thereby changing the damping coefficient of the shock absorber 14 in multiple stages.

  The stepping motor 40 is driven by sequentially exciting a plurality of coils by a control signal supplied from the drive circuit 46, and its rotational position is controlled by controlling the excitation pattern of the control signal. The drive circuit 46 uses the power supplied from the alternator 18 to generate a control signal with an excitation pattern according to a command from the attenuation coefficient control device 48. Therefore, the damping coefficient control device 48 controls the damping coefficient C of the shock absorber 14 via the drive circuit 46 and the actuator 42.

  A signal indicating the wheel speed (circumferential speed) Vwi of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel is input to the damping coefficient control device 48 from the wheel speed sensor 50i (i = fl, fr, rl, rr). Is done. The damping coefficient control device 48 and the engine control device 20 exchange signals with each other as necessary.

  In particular, when the control signal is not supplied to the stepping motor 38, the rotation angle of the stepping motor 38 becomes the angle of the standby position, and the actuator 42 is positioned at the preset standby position. When the actuator 42 is in the standby position, the valve opening amount of the damping force control valve 44 becomes a preset value, and the damping coefficient C of the shock absorber 14 becomes a holding value C0. Further, when the control signal is supplied to the stepping motor 38, the rotation angle of the stepping motor 38 sequentially increases step by step according to the excitation pattern of the control signal. As a result, the valve opening amount of the damping force control valve 44 also increases stepwise, whereby the damping coefficient C of the shock absorber 14 gradually decreases from C1 to Cn (n is a positive constant integer).

  FIG. 2 is a graph showing the damping force characteristics of the shock absorber 14. The horizontal axis indicates the suspension stroke speed Vs, and thus the relative speed of the cylinder 22 and the piston 24, and the vertical axis indicates the damping force Fd. As shown in FIG. 2, the damping force Fd is the largest when the damping coefficient C is the maximum value C1, and the smallest when the damping coefficient C is the minimum value Cn. The holding damping coefficient C0 is the same as that of the vehicle body when the damping coefficient C is C0, when the vehicle is stopped or when the vehicle speed is very low (collectively described as “stopped”). For example, an optimal arbitrary value obtained experimentally may be set so that a damping force suitable for posture change suppression or the like is generated. The holding attenuation coefficient C0 may be, for example, a value indicated by a broken line in FIG.

  Next, the damping coefficient control routine in the first embodiment will be described with reference to the flowchart shown in FIG. In the following description, the attenuation coefficient control according to the flowchart shown in FIG. 3 is simply referred to as “control”.

  The control according to the flowchart shown in FIG. 3 is started when an ignition switch (not shown) is switched from OFF to ON, and is repeatedly executed by the attenuation coefficient controller 48 at predetermined time intervals. At the start of control according to the flowchart shown in FIG. 3, prior to step 10, a flag F regarding whether or not the control position of the actuator 42 is the standby position and the damping coefficient is being controlled during the stop is set to the attenuation during the stop. Set to 1 to indicate that coefficient control is in progress. Also, the count value N of the counter for returning to normal damping force control is initialized to zero.

  First, in step 10, a signal indicating the wheel speed Vwi detected by the wheel speed sensor 50i is read, and whether or not the wheel speeds Vwi of all four wheels are equal to or less than a reference value Vw0 (a positive constant close to 0). Is determined. If a negative determination is made, the control proceeds to step 30; if an affirmative determination is made, the vehicle status VS is set to “stop” in step 20, and then the control proceeds to step 60.

  The reference value Vw0 is determined based on the rotation angle of the stepping motor 38 before the idling stop is executed, regardless of the reduction rate of the wheel speed Vwi and the damping coefficient C that occur in the general traveling state of the vehicle. It is set to the minimum value (constant) among the values that can be changed in a stepwise manner until the angle becomes. In other words, the reference value Vw0 is set to a value that allows the actuator 42 to be positioned at the standby position before the idling stop is performed without positioning the actuator 42 at the standby position too early. This value may be determined experimentally, for example.

  In step 30, it is determined whether or not the wheel speeds Vwi of all four wheels exceed the reference value Vw0. When an affirmative determination is made, the vehicle status VS is set to “running” at step 40, and when a negative determination is made, that is, when at least one wheel speed Vwi is equal to or lower than the reference value Vw0, the vehicle at step 50 The status VS is set to “undecided”. When step 40 or 50 is complete, control proceeds to step 60.

  In step 60, it is determined whether or not the vehicle status VS is "stopped". When a negative determination is made, the control proceeds to step 80, and when an affirmative determination is made, the control proceeds to step 70.

  In step 70, the flag F is set to “1” indicating that the damping coefficient control is being executed while the vehicle is stopped. Further, the count value N of the counter is set to the maximum value “Nc” (a positive constant integer) among the values indicating that it is not necessary to return the control of the attenuation coefficient to the normal control at the time of traveling, and then the control is performed. Proceeds to step 130.

  In step 80, it is determined whether or not the vehicle status VS is “running”. When an affirmative determination is made, the control proceeds to step 100. When a negative determination is made, the count value N of the counter is set to “Nc” at step 90, and then the control proceeds to step 130.

  In step 100, it is determined whether or not the count value N of the counter is 0, that is, whether or not it is necessary to return the damping coefficient control to the normal control during traveling. When an affirmative determination is made, the flag F is reset to “0” so that the damping coefficient control returns to the normal control at the time of travel in step 110, and when a negative determination is made, the count value N of the counter is determined in step 120. Is decremented by 1. When step 110 or 120 is complete, control proceeds to step 130.

  In step 130, it is determined whether or not the flag F is “1”, that is, whether or not the damping coefficient control is being executed while the vehicle is stopped. When an affirmative determination is made, the control proceeds to step 150, and when a negative determination is made, the control proceeds to step 140.

  In step 140, the excitation pattern of the control signal supplied to the stepping motor 38 while the vehicle is running is set to the excitation pattern for setting the damping coefficient C of the shock absorber 14 to the target damping coefficient by the normal control.

  In step 150, it is determined whether or not the actuator 42 is at the standby position, that is, whether or not the control of the actuator 42 during stopping is unnecessary. When a negative determination is made, the control proceeds to step 160. When an affirmative determination is made, in other words, when it is determined that control of the actuator 42 is unnecessary, a control signal is supplied to the stepping motor 38. However, the control is temporarily terminated and the process returns to Step 10.

  In step 160, the excitation pattern of the control signal supplied to the stepping motor 38 while the vehicle is stopped is set to an excitation pattern for sequentially changing the control position of the actuator 42 toward the standby position.

  In step 170, the actuator 42 is controlled by supplying the control signal of the excitation pattern set in step 140 or 160 to the stepping motor 38, whereby the damping coefficient C is controlled to a required value.

  FIG. 4 is a time chart showing the operation of the control device of the first embodiment as compared with the case of the conventional control device in the situation where the vehicle speed gradually decreases and the vehicle stops. In FIG. 4, the wheel speed Vwi of the four wheels is the same for convenience of explanation, and thus may be regarded as the same value as the actual vehicle speed, but the wheel speed Vwi of the four wheels may be different from each other. . The vehicle speed calculated based on the wheel speed Vwi is assumed to be an estimated vehicle speed Vva. Ne represents the engine speed, that is, the rotational speed of the engine 16, and Va represents the voltage generated by the alternator 18.

  As shown in FIG. 4, it is assumed that, for example, the wheel speeds Vwi of all the four wheels are equal to or lower than the reference value Vw0 at time t1, and the vehicle speed is stopped at time t2 because the wheel speed Vwi becomes 0. Further, it is assumed that an idling stop command is output at time t2 and fuel cut is started at time t3. Furthermore, it is assumed that the estimated vehicle speed Vva becomes 0 at time t4, and the generated voltage Va of the alternator 18 becomes equal to or lower than the drive guarantee voltage Vs0 (positive constant) of the stepping motor 38 at time t5.

  In the case of the conventional control device, even when the wheel speed Vwi becomes 0 and the vehicle stops at time t2, it takes time Δtx until it is determined that the estimated vehicle speed Vva becomes 0 and the vehicle has stopped. Further, it takes time Δty from the time when it is determined that the vehicle is stopped to the time when the stepping motor 38 is driven and the control position of the actuator 42 is switched to the standby position. Therefore, at time t6 when time Δtz, which is the sum of time Δtx and time Δty, elapses from time t2, the actuator 42 is positioned at the standby position, and the damping coefficient C becomes the holding value C0. Held at C0.

  Therefore, it is necessary to drive the stepping motor 38 even after the time t3 when the power generation voltage Va of the alternator 18 starts to decrease due to the execution of fuel cut. Therefore, step-out is likely to occur in the control of the shock absorber 14 after the time t3, particularly after the time t5.

  On the other hand, according to the first embodiment, the determination in steps 10, 60 and 130 is affirmative determination and the determination in step 150 is negative determination at time t1. Therefore, an excitation pattern control signal for changing the control position of the actuator 42 toward the standby position under the control of steps 160 and 170 is supplied to the stepping motor 38. As a result, at the time t1 ′ when the time Δty elapses from the time t1, the actuator 42 is positioned at the standby position, the damping coefficient C becomes the holding value C0, and thereafter the value C0 is held.

  As described above, the reference value Vw0 is used to position the actuator 42 at the standby position by sequentially changing the rotation angle of the stepping motor 38 until it reaches the standby position angle before the idling stop is executed. Is set to a value that can be Accordingly, since the time point t1 'comes before the time point t3, the actuator 42 can be positioned at the standby position before the power generation voltage Va of the alternator 18 starts to decrease, thereby stepping out of control of the shock absorber 14. Can be prevented.

  When the wheel speed Vwi is higher than the reference value Vw0, negative determination and positive determination are performed in steps 10 and 30, respectively. Therefore, negative determination, affirmative determination, and affirmative determination are performed in steps 60, 80, and 100, respectively, and negative determination is performed in step 130, whereby normal damping force control during vehicle travel is performed in steps 14 and 170. .

  Further, when the wheel speed Vwi is equal to or lower than the reference value Vw0 after the time point t1 ′, an affirmative determination is made in steps 10, 60, and 130, respectively. Therefore, since the control signal is not supplied to the stepping motor 38, the actuator 42 is held at the standby position, and the damping coefficient C is held at the holding value C0.

Although not shown in FIG. 4, when the vehicle resumes running and the wheel speed Vwi becomes higher than the reference value Vw0, first, a negative determination and an affirmative determination are made in steps 10 and 30, respectively. At 80, a negative determination and an affirmative determination are made, respectively. In this case, the count value N of the counter remains the value “Nc” set in step 70.
If the wheel speeds Vwi of all four wheels are not the same and a negative determination is made in step 30, a negative determination is made in steps 60 and 80, respectively, and the count value N of the counter is set to “Nc” in step 90. "Is reset.

  Furthermore, the count value N of the counter is gradually decreased by the positive determination in step 80, the negative determination in step 100, and the repetition of step 120. When the count value N of the counter becomes 0, an affirmative determination is performed in step 100, a flag F is reset to “0” in step 110, and a negative determination is performed in step 130, whereby the damping force is controlled. Return to normal control during vehicle travel.

  Steps 100 to 120 are steps for suppressing hunting of control of the control position of the actuator 42. By these steps, the actuator 42 is held at the standby position until it is determined that the running state of the vehicle is continuing.

  As understood from the above description, according to the first embodiment, the engine 16 is stopped by idling stop, and the control position of the actuator 42 is shifted to the standby position before the generated voltage Va of the alternator 18 starts to decrease. be able to. Accordingly, the intensity of the control signal supplied to the stepping motor 38 via the drive circuit 46 is reduced due to the decrease in the generated voltage Va, and the stepping motor 38 cannot be driven normally, and the control of the shock absorber 14 is stepped out. It can be prevented from occurring.

  In particular, the reference value Vw0 is sequentially increased step by step until the rotation angle of the stepping motor 38 reaches the angle of the standby position before the idling stop is executed regardless of the decrease rate of the wheel speed Vwi and the damping coefficient C. The minimum value among the values that can be changed is set. Accordingly, it is possible to prevent the step-out in the control of the shock absorber 14, and the damping coefficient C of the shock absorber 14 is controlled to the holding value C0 too early, which has an influence on the riding comfort of the vehicle. Can be reduced.

  Further, according to the first embodiment, the reference value Vw0 is a constant. Therefore, for example, as in the second embodiment described later, the shock absorber 14 is compared with a case where the vehicle deceleration Gxb is detected or estimated and the reference value Vw0 is variably set based on the vehicle deceleration Gxb. It is possible to easily perform control to prevent step-out from occurring in the control.

[Second Embodiment]
FIG. 5 is a flowchart showing a main part of a damping coefficient control routine in the second embodiment of the damping force variable shock absorber controller 10 according to the present invention applied to a stepping motor type damping force variable shock absorber. . In FIG. 5, the same step numbers as those shown in FIG. 3 are assigned to the same steps as those shown in FIG.

  In the second embodiment, steps 2 to 6 are executed before step 10, so that the reference value Vw0 (positive value) used for determining the wheel speed Vwi in steps 10 and 30 is obtained. Is variably set according to the deceleration of the vehicle. When step 6 is completed, the control proceeds to step 10, and each step after step 10 is executed in the same manner as in the first embodiment.

  First, in step 2, the estimated vehicle speed Vva is calculated based on the wheel speed Vwi, and the rate of change of the estimated vehicle speed Vva, that is, the deceleration Gxb of the vehicle is calculated with the estimated vehicle speed Vva being positive.

  In step 4, it is determined whether or not the vehicle deceleration Gxb is a positive value, that is, whether or not the estimated vehicle speed Vva is decreasing. When a negative determination is made, the control is temporarily terminated, and when an affirmative determination is made, the control proceeds to step 6.

In step 6, the reference value Vw0 is calculated from the map shown by the solid line in FIG. 6 based on the vehicle deceleration Gxb. As shown in FIG. 6, the reference value Vw0 is calculated so as to increase as the vehicle deceleration Gxb increases. In this case, the map line indicated by the solid line may be a curve of a function represented by the following equation (1), for example, where a and b are positive constants.
Vw0 = aa−Gxb (1)

  In FIG. 6, the hatched area indicates that the stepping motor 38 is in the standby position before the idling stop is executed regardless of the vehicle deceleration Gxb and the damping coefficient C that occur in the general traveling state of the vehicle. A reference value region that can be rotated to an angle of is shown. Moreover, in FIG. 6, the broken line has shown the reference value Vw0 of 1st embodiment.

  According to the second embodiment, the reference value Vw0 used for determining the wheel speed Vwi in steps 10 and 30 is set to the vehicle deceleration Gxb so that it increases as the vehicle deceleration Gxb increases. It is variably set accordingly.

  As in the first embodiment, when the reference value Vw0 is a constant value, the reference value Vw0 is set to a relatively large value. That is, the reference value Vw0 is relatively large so that the stepping motor 38 can be rotated to the standby position angle before the idling stop is executed regardless of the reduction rate of the wheel speed Vwi and the damping coefficient C. It must be a value.

  Therefore, when the reference value Vw0 is a constant value, as shown by the solid line in FIG. 7, when the vehicle deceleration Gxb is low, the time t1s is much earlier than the time t1 in FIG. The wheel speed Vwi becomes the reference value Vw0 or less. Therefore, at time t1s 'far earlier than time t1' in FIG. 4, the actuator 42 is positioned at the standby position, the damping coefficient C becomes the holding value C0, and thereafter the value C0 is held. Therefore, when the reference value Vw0 is a constant value and the vehicle deceleration is low, the damping coefficient C becomes the holding value C0 in the situation where the vehicle is traveling at a low speed. The ride comfort of the vehicle is affected. In FIG. 7, the phantom lines indicate the example shown in FIG.

  On the other hand, according to the second embodiment, the reference value Vw0 is variably set according to the vehicle deceleration Gxb so as to increase as the vehicle deceleration Gxb increases. Therefore, as shown in FIG. 8, when the deceleration Gxb of the vehicle is low, the wheel speed Vwi becomes equal to or less than the reference value Vw0 at time t1s substantially the same as time t1 in FIG. Therefore, when the vehicle is traveling at a low speed, the influence of the riding comfort of the vehicle by reducing the damping coefficient C to the holding value C0 can be reduced.

  Conversely, although not shown in the figure, when the vehicle deceleration Gxb is high, the reference value Vw0 is set to a large value. Therefore, the wheel speed Vwi becomes equal to or less than the reference value Vw0 at a time substantially the same as the time t1 in FIG. Therefore, switching the control position of the actuator 42 to complete the transition to the standby position can be prevented from the time t3 after the fuel cut is started and the power generation voltage Va of the alternator 18 starts to decrease. In other words, it is possible to prevent a step-out from occurring in the control of the shock absorber 14 due to the driving of the stepping motor 38 even after the time t3 when the generated voltage Va of the alternator 18 starts to decrease.

  Note that, as indicated by the alternate long and short dash line in FIG. 6, the reference value Vw0 may be calculated so as to increase stepwise as the vehicle deceleration Gxb increases. Further, as indicated by a two-dot chain line in FIG. 6, the reference value Vw0 is calculated so that the rate of increase of the reference value Vw0 with respect to the deceleration Gxb decreases stepwise as the vehicle deceleration Gxb increases. May be.

[Third embodiment]
FIG. 9 is a schematic configuration diagram showing a third embodiment of the control device 10 for a variable damping force shock absorber according to the present invention, which is applied to a linear solenoid variable damping force shock absorber. In FIG. 9, the same members as those shown in FIG. 1 are denoted by the same reference numerals as those shown in FIG.

  In the third embodiment, the actuator corresponding to the actuator 42 of the first and second embodiments is not connected to the upper end of the rod portion 24B. Instead, a linear solenoid actuator 60 is accommodated in the large diameter portion of the rod portion 24 </ b> B located in the cylinder 22.

  Although not shown in detail in FIG. 9, the actuator 60 includes a solenoid and a mover that is reciprocated along the longitudinal direction of the rod portion 24B by the electromagnetic force of the solenoid, and the mover is within a movable range. Arbitrary reciprocating positions can be taken. The actuator 60 controls the reciprocating position of the valve body of the damping force control valve 64 directly or via the control rod 62, thereby changing the valve opening amount of the damping force control valve 64 steplessly. Therefore, the actuator 60 changes the execution passage cross-sectional area of the communication passage connecting the cylinder upper chamber 26 and the cylinder lower chamber 28 steplessly, thereby changing the damping coefficient of the shock absorber 14 steplessly.

  A control signal is generated by the drive circuit 46 using the electric power supplied from the alternator 18, and the reciprocating position of the mover of the actuator 60 is controlled by the current Ic of the control signal. The drive circuit 46 controls the current Ic of the control signal by being controlled by the damping coefficient control device 48, whereby the damping coefficient control device 48 sets the damping coefficient C of the shock absorber 14 via the driving circuit 46 and the actuator 60. Control.

  In particular, when the control signal is not supplied to the actuator 60, the moving amount of the mover becomes 0, and the actuator 60 is positioned at a preset standby position. When the actuator 60 is in the standby position, the valve opening amount of the damping force control valve 64 becomes a preset value, and the damping coefficient C of the shock absorber 14 becomes the holding value C0. Further, as the current Ic of the control signal increases, the moving amount of the mover increases and the opening amount of the damping force control valve 64 also increases, whereby the damping coefficient C of the shock absorber 14 is changed from Cn to Cm (m is sequentially increasing to a positive constant integer less than n). Furthermore, the actuator 60 can change the valve opening amount of the damping force control valve 64 so that the damping coefficient C changes substantially instantaneously from one value to another value.

  In this embodiment, the engine control device 20 determines the operating state ES of the engine 16 including whether or not an idling stop is necessary by determining whether or not a preset condition is satisfied. Although the signal indicating the wheel speed Vwi is not input from the wheel speed sensor 50 i to the damping coefficient control device 48, the signal indicating the engine operating state ES is input from the engine control device 20.

  In the illustrated embodiment, the engine operating state ES changes from “1” to “4”. “1” indicates that the engine 16 is in an operation state that does not require idling stop, and “2” indicates that the engine 16 needs to shift to a stop state due to idling stop, and thus functions as an idling stop notice signal. . “3” indicates that the engine 16 is stopped due to idling stop, and “4” indicates that the engine 16 is restarted.

  FIG. 10 is a graph similar to FIG. 2 showing the damping force characteristics of the shock absorber 14. As shown in FIG. 10, the damping force Fd is the largest when the damping coefficient C is the maximum value Cm, and the smallest when the damping coefficient C is the minimum value Cn. As in the case of the other embodiments described above, the holding damping coefficient C0 is such that a damping force suitable for restraining a change in the posture of the vehicle body while the vehicle is stopped is generated when the damping coefficient C is C0. For example, it may be set to an optimum arbitrary value obtained experimentally. For example, the holding attenuation coefficient C0 may be a value indicated by a broken line in FIG.

  Next, the damping coefficient control routine in the third embodiment will be described with reference to the flowchart shown in FIG. In the following description, the attenuation coefficient control according to the flowchart shown in FIG. 11 is simply referred to as “control”.

  Control according to the flowchart shown in FIG. 11 is started when an ignition switch (not shown) is switched from OFF to ON, and is repeatedly executed by the attenuation coefficient control device 48 at predetermined time intervals. At the start of control according to the flowchart shown in FIG. 11, the count value M of the counter for returning to normal damping force control is initialized to 0 prior to step 310.

  First, in step 310, it is determined whether or not the engine operating state ES is “1”, that is, whether or not the engine 16 is in an operating state that does not require an idling stop. When a negative determination is made, control proceeds to step 360, and when an affirmative determination is made, control proceeds to step 320.

  Even when the engine operating state ES is “2”, that is, when there is a high probability that idling stop is executed, a negative determination is made in step 310. Therefore, in step 310, it is determined whether or not there is a high probability that idling stop is executed.

  In step 320, it is determined whether or not the previous engine operating state ES is other than “1”, that is, whether or not the engine operating state ES has changed from “2”, “3” or “4” to “1”. Is determined. According to this determination, it is determined whether or not the engine 16 has shifted from the stopped state to the operating state. When an affirmative determination is made, the count value M of the counter is set to “Mc” (a positive constant integer) at step 330, and when a negative determination is made, the count value M of the counter is decremented by 1 at step 340. Is done. When step 330 or 340 is complete, control proceeds to step 350.

  In step 350, it is determined whether or not the count value M of the counter is 0, that is, whether or not it is necessary to return the damping coefficient control to the normal control during traveling. When a negative determination is made, the current Ic of the control signal is controlled to 0 so that the actuator 42 is positioned at the standby position in step 360. On the other hand, when an affirmative determination is made, in step 370, the current Ic of the control signal is calculated so that the normal attenuation coefficient during traveling is controlled. When step 360 or 370 is complete, control proceeds to step 380.

  In step 380, the actuator 60 is controlled by controlling the drive circuit 46 so that the current Ic of the control signal becomes the voltage set in step 360 or 370, whereby the damping coefficient C is changed to the current Ic of the control signal. Controlled to the corresponding value.

  FIG. 12 shows vehicle speed. 6 is a time chart showing the operation of the control device of the third embodiment in a situation where the wheel speed Vwi gradually increases after the vehicle gradually stops and the vehicle temporarily stops. In FIG. 12, the wheel speed Vwi of the four wheels is the same for convenience of explanation, and thus may be regarded as the same value as the actual vehicle speed, but the wheel speed Vwi of the four wheels may be different from each other. .

  As shown in FIG. 12, it is assumed that the wheel speed Vwi starts to decrease at the time point t1, the wheel speed Vwi becomes 0 from the time point t2 to the time point t5, and the wheel speed Vwi gradually increases after the time point t5. Further, it is assumed that the engine operating state ES is “1” before time t2, becomes “2” at time t2, and becomes “3” from time t3 to time t4. Further, it is assumed that the engine operating state ES becomes “4” from the time point t4 to the time point t5, returns to “1” at the time point t5, and remains “1” thereafter.

  Before the time point t2, the engine operating state ES is “1” and the count value M of the counter is 0. Therefore, normal damping force control during vehicle travel is executed in steps 370 and 380. However, after the time point t2, the engine operating state ES becomes a value other than “1”, and the determination in step 310 is negative. Therefore, the current Ic of the control signal is controlled to 0 by the control in steps 360 and 380. . When the current Ic of the control signal is controlled to 0 at time t2, the actuator 60 is positioned at the standby position at time t2 'immediately thereafter.

  Further, after the time point t5, the engine operating state ES becomes “1”, but until the count value M of the counter becomes 0, the determination in step 350 is negative, so the control signal is controlled by the control in steps 360 and 380. Current Ic is controlled to zero. Therefore, if the time point when the count value M of the counter becomes 0 is t6, the actuator 60 is positioned at the standby position from time t2 'to time t6, and the damping coefficient C is held at the holding value C0. After time t6, normal damping force control during vehicle travel is executed.

  As shown in FIG. 12, at the time t3, the engine speed Ne starts to decrease due to idling stop, and the generated voltage Va of the alternator 18 starts to decrease correspondingly. However, since the engine operating state ES changes from “1” to “2” at time t2 before time t3, the current Ic of the control signal is controlled to 0 before the generated voltage Va begins to decrease, The actuator 60 is positioned at the standby position substantially immediately. Therefore, it is possible to prevent the control position of the actuator 60 from being switched to the standby position and the step-out in the control of the shock absorber 14 due to this in the process in which the power generation voltage Va is decreasing.

  In particular, according to the third embodiment, even when the engine operating state ES becomes “1” at time t5, the current Ic of the control signal is controlled to 0 until time t6 when the count value M of the counter becomes 0. The control position of the actuator 60 is held at the standby position. Therefore, it is possible to prevent the actuator 60 from being driven to a control position other than the standby position in the process in which the engine speed Ne after the time point t5 starts to increase and the power generation voltage Va of the alternator 18 increases from 0. . Therefore, it is possible to prevent a step-out from occurring in the control of the shock absorber 14 in a situation where the control of the damping force returns to the normal damping force control during vehicle travel.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. This will be apparent to those skilled in the art.

  For example, in the first and second embodiments described above, the vehicle speed of the reference value for starting and releasing the idling stop is 0, but this reference value may be set to a positive value smaller than the reference value Vw0. .

  Further, in the first and second embodiments described above, control of the reference value of the wheel speed and the damping coefficient of the shock absorber for determining whether or not the control position of the actuator 42 should be switched to the standby position is performed normally. The wheel speed reference values for determining whether or not to return to control are all the same value of Vw0. However, the latter reference value may be set to a value larger than the former reference value. According to this correction, in a situation where the wheel speed fluctuates in the vicinity of the reference value, the control of the damping coefficient of the shock absorber repeatedly fluctuates between normal control when the vehicle travels and holding of the damping coefficient while the vehicle is stopped. Hunting can be suppressed.

  Further, in the above-described third embodiment, when the vehicle speed becomes zero, the engine operating state ES changes from “1” to “2”. However, even if the engine operating state ES changes from “1” to “2”, which functions as an idling stop notice signal, even when the vehicle speed is less than a small positive value greater than 0, it is corrected to be performed. Good.

  In the above-described third embodiment, when it is determined in step 310 that the engine operating state ES is “1”, steps 320 to 350 are executed. However, if these steps are omitted and an affirmative determination is made in step 310, control may be modified to proceed to step 370.

  DESCRIPTION OF SYMBOLS 10 ... Control device of variable damping force type shock absorber, 14 ... Shock absorber, 16 ... Engine, 18 ... Alternator, 20 ... Engine control device, 34 ... Damping force control valve, 42 ... Rotary actuator, 46 ... Drive circuit, 48 ... damping coefficient control device, 50i ... wheel speed sensor, 60 ... linear solenoid actuator, 64 ... damping force control valve

Claims (7)

  An engine control device that stops the engine by idling stop when the vehicle speed falls below the stop reference value, an alternator that generates electric power by being driven by the engine, and an actuator that drives the damping force control valve to change the damping coefficient Attenuation mounted on a vehicle having a damping force variable shock absorber, generating a control signal using electric power supplied from the alternator, and controlling a damping coefficient by controlling a control position of the actuator by the control signal In the force-variable shock absorber control device, the shock absorber control device determines a probability that the idling stop is executed, and when it is determined that the probability of the execution is high, the shock absorber control device moves toward the preset standby position. Switching the control position of the actuator Started, the control unit of the damping force control shock absorber, characterized in that to complete the switching to the standby position before the idling stop is performed.   The control apparatus for a variable damping force shock absorber according to claim 1, wherein the control apparatus for the shock absorber until the idling stop is released or the probability that the idling stop is released is determined to be high. A control device for a shock absorber with variable damping force, wherein the control position of the actuator is held at the standby position.   3. The damping force variable shock absorber control device according to claim 1 or 2, wherein the actuator is a stepping motor type actuator.   4. The damping force variable shock absorber control device according to claim 3, wherein the shock absorber control device determines that the standby is performed when it is determined that the vehicle speed has fallen below a control start reference value higher than the stop reference value. A control device for a damping force variable shock absorber, which starts switching the control position of the actuator to a position.   5. The control device for a damping force variable shock absorber according to claim 4, wherein the control start reference value is variably set according to a decrease rate of the vehicle speed so as to increase as the decrease rate of the vehicle speed increases. Control device for variable damping force shock absorber.   3. The control apparatus for a variable damping force shock absorber according to claim 1, wherein the actuator is a linear solenoid type actuator.   7. The damping force variable shock absorber control device according to claim 6, wherein the engine control device idles to the shock absorber control device when a vehicle speed falls below a warning reference value higher than the stop reference value. A damping advance variable signal is transmitted, and the shock absorber control device starts switching the control position of the actuator to the standby position when the idling stop advance notice signal is received. Absorber control device.

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