JPH11208439A - Vehicle stop control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce backlash of a vehicle body and a shock resulting from this while avoiding an increase in a braking distance of a vehicle. SOLUTION: It is determined whether or not the vehicle is in a relatively abrupt braking stop state and there is a possibility that the vehicle will swing back (S10).
20, 50, 60), it is determined whether or not the vehicle body has substantially stopped (S70). When the vehicle body has stopped due to braking of the vehicle when traveling on a horizontal road (S70 and 90), the suspension of the front and rear wheels is performed. Until the stroke speed becomes substantially zero, the braking force of each wheel is controlled to zero, the wheels are moved forward relative to the vehicle body by the reaction of the restoring force of the suspension, and the body is prevented from rolling back. In addition, the extension-side damping force of the front wheel shock absorber and the contraction-side damping force of the rear wheel shock absorber are controlled to the maximum to reduce the posture restoring speed of the vehicle body (S100, 140, 150).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stop control device for a vehicle, and more particularly to a stop control device for reducing a shock caused by a turning of a vehicle body when the vehicle stops.

[0002]

2. Description of the Related Art As is well known, when a vehicle such as an automobile is stopped by braking, a vehicle body (spring-up) is provided immediately before the vehicle stops.
Is leaning forward due to forward load movement (nose dive)
Immediately after the vehicle stops, the vehicle's center of gravity is moved backward by the restoring force of the suspension, causing the vehicle to pitch, and the occupant of the vehicle feels this behavior of the vehicle as an unpleasant swing of the vehicle.

One example of a vehicle stop control device for reducing the backlash of the vehicle body and the shock caused by the vehicle stop when the vehicle stops is described in, for example, JP-A-1-164656 filed by the present applicant. As has been done,
When the vehicle speed becomes equal to or lower than a predetermined value when the vehicle is stopped, a stop control device (brake device) configured to automatically reduce the braking force on the wheels, thereby reducing the swinging back of the vehicle body and the shock resulting from this, is provided. Conventionally known.

[0004]

According to the above-described stop control device, it is possible to reduce the backlash of the vehicle body when the vehicle is stopped and to reduce the shock caused by this. In this case, since the deceleration acceleration of the vehicle body before the stop is reduced, the energy of the vehicle swinging back is reduced, so that there is a problem that the braking distance of the vehicle is inevitably increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in a conventional stop control device configured to automatically reduce a braking force on wheels when a vehicle speed falls below a predetermined value when the vehicle is stopped. The main problem of the present invention is:
By controlling the braking force so that the wheels move forward relative to the vehicle body when the vehicle is stopped, it is possible to prevent the vehicle from swinging over a long distance and reduce the vehicle's swingback and the resulting shock. That is.

[0006]

According to the present invention, the main object of the present invention is to provide an apparatus for detecting a braking state of a vehicle and a method of substantially stopping a vehicle body as a sprung body. A braking device capable of controlling the braking force on the wheels irrespective of the braking operation by the driver if necessary, and a braking device for the wheels for a predetermined time from the moment when the sprung material substantially stops during braking of the vehicle. Control means for substantially canceling the braking force.

In general, the mass of the wheels (unsprung) is much smaller than the mass of the vehicle (springs). Therefore, if the braking force on the wheels is released at the same time when the vehicle stops when the vehicle stops, the suspension is restored. Due to the reaction of the force, the wheels are moved to the front of the vehicle relative to the vehicle body, whereby the vehicle body is not moved to the rear of the vehicle relatively to the wheels, and the posture of the vehicle body is more normal than the forward leaning posture. To restore.

According to the first aspect of the present invention, the braking force on the wheels is substantially released by the control means for a predetermined time from the moment when the sprung mass is substantially stopped during braking of the vehicle. When the vehicle is restored from the normal posture to the normal posture, the wheels move forward with respect to the vehicle body, and the vehicle body does not move rearward with respect to the wheels. Swinging and the resulting shock are effectively reduced. In addition, since the braking force is not released or reduced before the sprung state is substantially stopped, the braking distance of the vehicle is not increased by the control of the stop control device.

According to the present invention, in order to effectively achieve the above-mentioned main object, the vehicle according to the first aspect of the present invention has a variable damping force type shock absorber, and the control means. Is configured to increase the damping force of the shock absorber at least until the predetermined time elapses from the moment when the vehicle body substantially stops (the configuration of claim 2).

According to the second aspect of the present invention, the damping force of the shock absorber is increased by the control means until at least a predetermined time elapses from the moment when the vehicle body substantially stops, so that the vehicle body leans forward. The change in the pitching angle when restoring to a more normal posture becomes gentler, so that the shock caused by the sway of the vehicle body is more effective than when the damping force of the shock absorber is not increased as described above. To be reduced.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of the first aspect, the stop control device has means for detecting a direction of inclination of a road surface, Different control is performed in accordance with the direction of inclination of the road surface (the configuration of claim 3).

In general, when a vehicle stops on an inclined road, a component of gravity in the vehicle longitudinal direction acts on the vehicle,
Also, depending on whether the slope is downhill or uphill, in other words, the direction of the component of gravity acting on the vehicle in the front-rear direction of the vehicle differs depending on the inclination direction of the road surface, and therefore, the vehicle acting on the vehicle body when the vehicle stops. The force in the front-rear direction is different from that when the vehicle stops on a horizontal road, and also depends on the inclination direction of the road surface.

According to the third aspect of the present invention, different controls are performed in accordance with the direction of inclination of the road surface, so that the same control is performed regardless of the direction of inclination of the road surface. The vehicle can be appropriately stopped in accordance with the acting force in the front-rear direction of the vehicle.

According to the present invention, in order to effectively attain the above-mentioned main object, in the above-mentioned configuration, the stop control device may be configured to stop the vehicle when the road surface on which the vehicle stops is downhill. The control for substantially canceling the braking force on the wheel is prohibited (the configuration of claim 4).

In general, when a vehicle stops on a downhill, the body acting immediately after the vehicle stops compared to when stopping on a horizontal road due to the component of gravity acting on the vehicle ahead of the vehicle. Is small, but the braking distance of the vehicle tends to be long. According to the above configuration, when the road surface on which the vehicle stops is on a downhill, the control for substantially canceling the braking force on the wheels is prohibited, so that when the vehicle stops on the downhill, the braking of the vehicle is stopped. Longer distances are reliably avoided.

According to the present invention, in order to effectively achieve the above-mentioned main object, in the configuration of the above-mentioned claim 1, the stop control device may include a driving force for a wheel irrespective of a driving operation by a driver. And a driving force applied to the wheels by the driving device to such an extent that the wheels do not retreat when the road surface on which the vehicle stops is on an uphill (claim 5).

In general, when a vehicle stops on an uphill, the vehicle body immediately after the vehicle stops compared to when stopping on a horizontal road due to the component of gravity acting on the vehicle toward the rear of the vehicle. The amount of backward movement of the vehicle is likely to be large, and the vehicle is likely to retreat. According to the configuration of the fifth aspect, when the road surface on which the vehicle stops is on an uphill, the braking force on the wheels is released and the driving force is applied to the wheels by the driving device to such an extent that the wheels do not retreat. Even when stopping on an uphill, the wheels are reliably moved forward relative to the vehicle body due to the reaction of the restoring force of the suspension, so that the vehicle body swings back and the resulting shock is effectively reduced. Therefore, it is possible to reliably prevent the vehicle from retreating and the stop position of the vehicle from being behind the desired position.

According to the present invention, in order to achieve the above-mentioned main object effectively, in the configuration of the first aspect, the stop control device has a means for detecting a stroke speed of the suspension, The predetermined time is configured to be a time until the stroke speed of the suspension becomes substantially zero (configuration of claim 6).

As described above, the swingback of the vehicle body when the vehicle is stopped is a phenomenon generated by the restoring force of the suspension, and the time when the stroke speed of the suspension becomes substantially zero after the vehicle is stopped is determined. This is the end point of the swinging behavior of. According to the configuration of the sixth aspect, the time until the stroke speed of the suspension becomes substantially zero is set as the predetermined time, and the braking force on the wheels is controlled by the predetermined time control means from the moment when the sprung spring is substantially stopped. Is substantially released, so that the release of the braking force on the wheels can be executed for an optimal time without excess or shortage.

[0020]

According to a preferred aspect of the present invention, in the configuration of the first aspect, the means for detecting a braking state of the vehicle is configured to detect a depressed state of a brake pedal operated by a driver. It is configured to detect (preferred embodiment 1).

According to another preferred embodiment of the present invention, in the configuration of the first aspect, the means for detecting that the vehicle body is substantially stopped is provided when the ground speed of the vehicle body is substantially zero.
(Preferred mode 2).

According to another preferred embodiment of the present invention, in the configuration of the first aspect, the stop control device has a means for detecting a deceleration of the vehicle, and the control means is provided when the vehicle is braked. When the deceleration of the vehicle is equal to or more than the reference value, the braking force on the wheels is substantially released for a predetermined time from the moment when the vehicle body substantially stops (preferred mode 3).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned claim 1, the stop control device includes a main switch operated by a driver, and the stop control device is provided when the main switch is on. It is configured to operate only (preferred embodiment 4).

According to another preferred aspect of the present invention, in the configuration of the second aspect, the shock absorber can control the damping force on the extension side and the damping force on the contraction side independently of each other. It is configured to increase the extension-side damping force of the front wheel shock absorber and the contraction-side damping force of the rear wheel shock absorber (preferred mode 5).

According to another preferred embodiment of the present invention, in the configuration of the preferred embodiment 5, the control means includes a damping coefficient on the extension side of the shock absorber for the front wheel and a damping coefficient on the compression side of the shock absorber for the rear wheel. The coefficient is configured to be controlled to substantially the critical damping coefficient (preferred embodiment 6).

According to another preferred embodiment of the present invention, in the configuration of the above-mentioned preferred embodiment 5 or 6, the control means includes a damping force on a contraction side of the front wheel shock absorber until the vehicle body substantially stops. It is configured to increase the extension-side damping force of the rear wheel shock absorber (preferred mode 7).

According to another preferred aspect of the present invention, in the configuration according to the fifth aspect, the means for detecting the direction of inclination of the road surface also detects the inclination angle of the road surface, and the stop control device includes: It is configured to apply a driving force to the wheels according to the inclination angle (preferred mode 8).

According to another preferred embodiment of the present invention, in the configuration of claim 6, the means for detecting the stroke speed of the suspension includes a means for detecting the stroke of the suspension, and a means for detecting the stroke of the suspension. Means for calculating the time differential value of the stroke (preferred mode 9).

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram (A) showing one embodiment of a vehicle stop control device according to the present invention applied to a rear wheel drive vehicle, and a block diagram (B) of a control system.

In FIG. 1, reference numeral 10 denotes an engine, and a driving force of the engine 10 is transmitted to a propeller shaft 18 via an automatic transmission 16 including a torque converter 12 and a transmission 14. The driving force of the propeller shaft 18 is transmitted to the left rear wheel axle 22L and the right rear wheel axle 22R by the differential 20, whereby the left and right rear wheels 24RL and 24RR, which are the driving wheels, are driven to rotate.

On the other hand, the left and right front wheels 24FL and 24FR are both driven wheels and steered wheels. Although not shown in FIG. 1, a rack and pinion driven in response to turning of the steering wheel by a driver is provided. It is steered through a tie rod by a power steering device of the type.

The output of the engine 10 is controlled by a throttle valve 28 provided in an intake passage 26. The opening of the throttle valve 28 is normally controlled by an engine control computer 32 according to the amount of depression of an accelerator pedal 30 operated by a driver. As described later, the engine control computer 32 controls the vehicle based on a control signal from the stop control computer 36 regardless of the amount of depression of the accelerator pedal 30 when the vehicle stops braking, as will be described later. It is controlled via an actuator 34.

The suspensions of the left and right front wheels 24FL and 24FR are respectively provided with variable damping force type shock absorbers 38.
FL, 38FR are provided, left and right rear wheels 24RL, 24
The suspension of the RR is provided with shock absorbers 38RL and 38RR of variable damping force. Normally, the shock absorbers 38FL to 38RR are controlled by a damping force control computer 40 via an actuator not shown in the drawings based on a detection result of a lateral acceleration sensor or the like not shown in the drawing. At the time of braking stop, it is controlled by the damping force control computer 40 based on a control signal from the stop control computer 36 as necessary.

The braking force of the left and right front wheels 24FL, 24FR and the left and right rear wheels 24RL, 24RR is applied to the hydraulic circuit 44 of the braking device 42.
The corresponding wheel cylinders 46FL, 46FR, 46
It is controlled by controlling the braking pressures of RL and 46RR. Although not shown in the drawing, the hydraulic circuit 44 includes a reservoir, an oil pump, various valve devices, and the like, and the braking pressure of each wheel cylinder is normally driven in accordance with the depression operation of the brake pedal 48 by the driver. It is controlled by a master cylinder 50 and, if necessary, by an automatic brake control computer 52 as will be described in detail later.

As will be described later in detail, the automatic brake control computer 52 and the brake device 42 respond to a control signal from the stop control computer 36 when the vehicle is parked or stopped by the stop device, and are involved in the depression operation of the brake pedal 48 by the driver. Automatic braking device 5 that controls braking force without
4.

As shown in FIG. 1B, the stop control computer 36 receives a signal indicating the vehicle speed V from the vehicle speed sensor 56 and a vehicle speed Vb from the ground vehicle speed sensor 58.
Signal indicating the inclination angle φ of the road surface in the vehicle front-rear direction from the inclination angle sensor 60, and the stroke sensors 62FL, 62
Signals indicating suspension strokes Sfl, Sfr, Srl, and Srr of the front left wheel 24FL, front right wheel 24FR, rear left wheel 24RL, and rear right wheel 24RR are input from FR, 62RL, and 62RR, respectively.

The inclination angle sensor 60 may be of any configuration known in the art as long as it can detect the inclination angle of the road surface in the vehicle front-rear direction. In particular, the inclination angle sensor 60 detects the road surface inclination angle component of gravity. In the case of a sensor that detects the longitudinal acceleration of the vehicle body, it is preferable that the detected value be corrected at the rate of change Vd of the vehicle speed V so that the error caused by acceleration and deceleration of the vehicle is not superimposed on the detected value.

A signal indicating whether or not the driver has depressed the brake pedal 48 from a brake pedal switch (BKSW) 64 is provided to the stop control computer 36. A parking brake pedal switch (PBKS)
W) 66, a signal indicating whether a parking brake (not shown in FIG. 1) is on, or a main switch 68 for activating a stop device indicating whether the switch is on. Is entered.

The stop control computer 36 determines in accordance with the flowcharts shown in FIGS. 2 and 3 whether or not the vehicle is in a relatively sharp braking stop state and there is a possibility that the vehicle will roll back. When there is a possibility that the rocking may occur, a control signal is output to the engine control computer 32, the damping force control computer 40, and the automatic brake control computer 52 depending on whether the road surface is a horizontal road, an uphill, or a downhill, This prevents the vehicle from turning over when the vehicle is stopped while avoiding an increase in the braking distance of the vehicle.

The engine control computer 32, the stop control computer 36, the damping force control computer 40, and the automatic brake control computer 52 are actually microcomputers having a well-known configuration including a CPU, a ROM, a RAM, and an input / output port device. May be.

Next, the stop control in the illustrated embodiment will be described with reference to the flowcharts shown in FIGS. The control according to the flowcharts shown in FIGS. 2 and 3 is started by closing a main switch 68 (not shown).

First, at step 10, a signal indicating the vehicle speed V detected by the vehicle speed sensor 54 is read, and at step 20, for example, the rate of change Vd of the vehicle speed as a time differential value of the vehicle speed V is read. Is calculated, and V
With do as a positive constant, it is determined whether or not the vehicle speed change rate Vd is equal to or less than the reference value -Vdo, that is, whether or not the vehicle is in a relatively rapid deceleration state, and a negative determination is made. When the shock absorber 38FL
.About.38RR is controlled by the damping force control computer 40 in the normal control mode, and the process proceeds to step 40 when a negative determination is made.

In step 40, the left and right front wheels 24F
The damping force on the compression side of the shock absorbers 38FL and 38FR of the L and 24FR is controlled to increase so as to be higher than the damping force in the normal control mode, and the left and right rear wheels 24RL and 24RL are controlled.
The damping force on the extension side of the shock absorbers 38RL, 38RR of the RR is controlled to increase so as to be higher than the damping force in the normal control mode.

In step 50, it is determined whether or not the vehicle speed V is equal to or less than a reference value Vo (positive constant), that is, whether or not the vehicle is in a state immediately before stopping, and a negative determination is made. When the determination is made, the process directly returns to step 10, and when the affirmative determination is made, it is determined in step 60 whether or not the brake pedal switch 64 is in the ON state, that is, whether or not the driver is performing a braking operation. When a negative determination is made, the process returns to step 10, and when an affirmative determination is made, the process proceeds to step 70.

In step 70, the ground vehicle speed V
It is determined whether or not b is substantially 0, that is, whether or not the vehicle body has substantially stopped. If a negative determination is made, the process returns to step 10, and if an affirmative determination is made, In step 80, the extension damping force of the left and right front wheel shock absorbers 38FL, 38FR is set to the maximum value, and the left and right rear wheel shock absorbers 38RL, 38
The damping force on the contraction side of RR is set to the maximum value. In this case, the control for setting the damping force to the maximum value is achieved by increasing the damping coefficient to, for example, a critical damping coefficient so that the pitching of the vehicle body when braking is stopped substantially converges in one cycle.

In step 90, for example, it is determined whether or not the road surface is a horizontal road by determining whether or not the absolute value of the road surface inclination angle φ detected by the inclination angle sensor 60 is equal to or smaller than a reference value. Is performed, and when an affirmative determination is made, in step 100 the automatic brake control computer 5
When the control signal is output to No. 2, the braking force of each wheel is released to become substantially zero, and when a negative determination is made, the process proceeds to Step 110.

In step 110, it is determined whether or not the road surface is uphill based on the sign of the inclination angle φ of the road surface.
Proceeding to 40, if a positive determination is made, step 12
At 0, the braking force of each wheel is released so as to become substantially 0. At step 130, based on the inclination angle φ of the road surface, it is necessary to prevent the vehicle from moving backward from a map (not shown). The target opening of the throttle valve 28 is calculated, and a signal indicating the target opening is output to the engine control computer 32, whereby the driving force (output of the engine 10) for preventing the vehicle body from moving backward is controlled. .

In step 140, based on the strokes Sfl and Sfr detected by the left and right front wheel stroke sensors 62FL and 62FR, for example, respective stroke speeds Vsfl and Vsfr are calculated as time differential values, and the average value thereof is calculated. The front wheel stroke speed Vsf is calculated, and it is determined whether or not the stroke speed Vsf is substantially 0. If a negative determination is made, the process returns to step 90; Proceed to 150.

Similarly, in step 150, based on the strokes Srl and Srr detected by the straw sensors 62RL and 62RR of the left and right rear wheels, the respective stroke speeds Vsrl and Vsrr are calculated as time differential values, for example. The stroke speed Vsr of the rear wheel is calculated as an average value of the rear wheel, and it is determined whether or not the stroke speed Vsr is substantially 0. When a negative determination is made, the process returns to step 90, and an affirmative determination is made. If so, go to step 160.

In step 160, the control of the damping force of each shock absorber is returned to the normal control mode, and in step 170, a braking force is applied again to each wheel so that they do not move. In this case, it is determined whether or not the parking brake switch 66 is in the on state, and whether or not the driver has performed the stop state maintaining operation. If a negative determination is made, the process returns to step 170. If the determination is affirmative, the program proceeds to step 190 where the automatic brake control computer 5
When the control signal is output to the second control mode, the control mode of the braking force of each wheel is returned to the normal control mode.

Although not shown in FIGS. 2 and 3, even when the main switch 68 is turned off, the control mode of the damping force of the shock absorber and the control mode of the braking force of each wheel are respectively normal. Is returned to the control mode.

Thus, according to the illustrated embodiment, in steps 20, 50 and 60, it is determined whether or not the vehicle is in a relatively abrupt braking stop state and there is a possibility that the vehicle will swing back. In step 70, it is determined whether or not the vehicle body has substantially stopped. If the vehicle stops by braking while the vehicle is traveling on a horizontal road and the vehicle body stops, in steps 70 and 90, A positive determination is made,
In steps 100, 140, and 150, the braking force of each wheel is controlled to 0 for a predetermined time.

As shown in FIG. 4 (A), a normal vehicle 100 not equipped with the stopping device according to the present invention travels at a substantially constant vehicle speed in a direction indicated by a white arrow 102. In this case, the vehicle body 108 supported by the front wheels 106F and the rear wheels 106R via the suspension springs 104F and 104R respectively is in a substantially horizontal state.

As shown in FIG. 4B, when the vehicle 100 is relatively rapidly decelerated by braking, a load shift occurs in the front of the vehicle as shown by a black arrow 110, and the front wheels are moved. The suspension spring 104F on the rear side shrinks and the suspension spring 104R on the rear wheel side
Is extended, the vehicle body 108 assumes a forward leaning posture.

Further, as shown in FIG. 4C, even if the wheels 106F and 106R stop due to braking, the vehicle body 10
Numeral 8 moves to the front of the vehicle due to inertial force, the front-wheel-side suspension spring 104F further contracts, and the rear-wheel-side suspension spring 104R further expands.
The vehicle body stops in a state where the wheel 12 is displaced forward with respect to the wheels 106F and 106R.

Therefore, as shown in FIG.
Immediately after the vehicle body 108 stops, the vehicle body is moved to the center of gravity 11 by the restoring force of the suspension springs 104F and 104R.
2 is biased so as to be displaced rearward of the vehicle, so that the vehicle is pitched backward. This causes pitching of the vehicle body, so that the occupant of the vehicle immediately displaces the vehicle rearward immediately after stopping the vehicle. It is inevitable to feel it as a reflection.

On the other hand, according to the embodiment shown in FIG.
When the wheels 106F and 106R stop and the vehicle body 108 stops in the forward leaning posture as shown in FIG.
The braking force on the wheels 6F and 106R is released, so that the wheels 106F and 106R slightly advance due to the reaction of the restoring force of the suspension springs 104F and 104R as shown in FIG. It returns to a substantially horizontal posture as shown in FIG. 5 (E) without displacing backward. Therefore, it is possible to surely prevent the occupant of the vehicle from feeling uncomfortable swinging of the vehicle body immediately after the vehicle stops and the shock caused by the swaying.

When the vehicle stops on a downhill, the braking distance of the vehicle tends to be longer than when the vehicle stops on a horizontal road due to the gravity component acting on the vehicle in front of the vehicle. According to the illustrated embodiment, when the vehicle stops on a downhill, the release of the braking force is prohibited, so that when the vehicle stops on a downhill, the braking distance of the vehicle becomes longer. It can be reliably prevented. In this case, the amount of backward movement of the vehicle body immediately after stopping the vehicle is smaller than that when stopping on a horizontal road due to the component of gravity acting on the vehicle in front of the vehicle. Even if prohibited, the occupants of the vehicle will not feel a large swing of the vehicle body or a strong shock due to this.

Further, when the vehicle stops on an uphill, the amount of rearward movement of the vehicle body is larger than when the vehicle stops on a horizontal road due to the component of gravity acting on the vehicle toward the rear of the vehicle. It is easy for the vehicle to retreat. According to the illustrated embodiment, when the vehicle stops on an uphill, the braking force on the wheels is released and the driving force is applied to the wheels to the extent that the wheels do not retreat. When the vehicle is stopped, the wheels can be reliably moved forward relative to the vehicle body by the reaction of the restoring force of the suspension, thereby effectively reducing the vehicle's rolling back and the resulting shock. Can be.

In particular, according to the illustrated embodiment, when the vehicle substantially stops when braking of the vehicle is stopped, in step 80, the extension side damping force of the front wheel shock absorbers 38FL and 38FR and the rear wheel shock absorber 38RL. , 38RR
The damping force on the contraction side is set to the maximum value, so that the vehicle body slowly returns to the normal posture without repeating the forward and backward swings, and therefore, the control of the damping force is not performed further. It is possible to surely reduce the backlash of the vehicle body and the shock caused by this.

Also, according to the illustrated embodiment, step 2
At 0, it is determined whether or not there is a high possibility that the vehicle body will swing back by determining whether or not the vehicle speed change rate Vd is equal to or less than the reference value -Vdo. Is performed only in a situation where the engine speed is high, so that the possibility of unnecessary control of the braking force and control of the damping force of the shock absorber is reduced as compared with a case where such determination is not performed. be able to.

Further according to the illustrated embodiment, step 2
If an affirmative determination is made in step 0, in step 40, the damping force on the compression side of the front wheel shock absorbers 38FL, 38FR and the rear wheel shock absorbers 38RL, 38
Since the damping force on the extension side of the RR is controlled to increase so as to be higher than the damping force in the normal control mode, it is possible to reduce the degree of forward lean of the vehicle body when the vehicle is stopped, thereby reducing the damping force. , And the shock resulting therefrom can be reduced more reliably than when the above control is not performed. Also, in this case, the damping force on both the extension side and the contraction side of each shock absorber is not controlled to increase, so that it is possible to reliably prevent the ride comfort of the vehicle from being deteriorated by the control of increasing the damping force.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the above-described embodiment, when an affirmative determination is made in step 20, step 4
At 0, the control to increase the damping force of the shock absorber is performed, but the control to increase the damping force at step 40 may be omitted.

In the above-described embodiment, if it is determined in steps 140 and 150 that the stroke speed of the front and rear wheel suspensions is substantially zero, then in steps 160 and 170, respectively. Although the damping force control and the braking force release control are terminated, the time of the damping force control and the braking force release control may be set to a constant value. Speed V and the rate of change V at the time when
Based on d, they may be variably set to be longer as they are higher.

Further, in the above-described embodiment, when a negative determination is made in step 180, the process directly returns to step 170. However, when a negative determination is made in step 180, the timer is activated. The alarm device (not shown) may be configured to be activated when the count value exceeds the reference value.

[0068]

As is apparent from the above description, according to the structure of the first aspect of the present invention, even when the vehicle body is restored from the forward leaning posture to the normal posture when the vehicle stops braking, the wheels stay on the vehicle body. On the other hand, since the vehicle moves relatively to the front of the vehicle, and the vehicle body does not move rearward of the vehicle relative to the wheels, it is possible to effectively reduce the backlash of the vehicle body when the vehicle is stopped and the shock caused thereby. Also, since the braking force is not released or reduced before the sprung state is substantially stopped, it is necessary to reliably prevent the braking distance of the vehicle from being lengthened by the control of the stop control device. Can be.

According to the second aspect of the present invention, the damping force of the shock absorber is increased at least until a predetermined time elapses from the moment when the sprung mass is substantially stopped. The change of the pitching angle when restoring to the normal posture can be moderated, which further reduces the shock caused by the swing of the vehicle body as compared with the case where the damping force of the shock absorber is not increased as described above. It can be more effectively reduced.

According to the third aspect of the present invention, since different controls are performed in accordance with the direction of inclination of the road surface, the vehicle body stops when the vehicle stops, compared to the case where the same control is performed regardless of the direction of inclination of the road surface. The vehicle can be appropriately stopped in accordance with the longitudinal force acting on the vehicle.

According to the fourth aspect of the present invention, when the road surface on which the vehicle stops is on a downhill, the control for substantially canceling the braking force on the wheels is prohibited. An increase in the braking distance of the vehicle can be reliably avoided. Also, in this case, the amount of rearward movement of the vehicle body immediately after stopping the vehicle is smaller than that when stopping on a horizontal road due to the component of gravity acting on the vehicle in front of the vehicle. As a result, excessive swinging of the vehicle body does not occur.

According to the fifth aspect of the present invention, when the road surface on which the vehicle stops is an uphill, the driving force is applied to the wheels by the driving device to such an extent that the wheels do not retreat, so that when the vehicle stops on the uphill. In addition, the wheels are reliably moved forward relative to the vehicle body due to the reaction of the restoring force of the suspension, so that the vehicle body can be effectively swung back and the resulting shock can be effectively reduced, and the vehicle moves backward. Thus, it is possible to reliably prevent the stop position of the vehicle from being behind the desired position.

According to the structure of claim 6, the time until the stroke speed of the suspension becomes substantially zero is defined as the predetermined time, and the wheel control is performed by the predetermined time control means from the moment when the sprung spring is substantially stopped. Is controlled to substantially zero, so that the control to substantially reduce the braking force to the wheels can be optimally executed without excess or deficiency.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram (A) showing one embodiment of a vehicle stop control device according to the present invention applied to a rear wheel drive vehicle, and a block diagram (B) of a control system.

FIG. 2 is a flowchart illustrating a first half of a stop control routine according to the embodiment.

FIG. 3 is a flowchart illustrating the latter half of a stop control routine according to the embodiment.

FIG. 4 is an explanatory diagram exaggeratingly illustrating the behavior of a vehicle body when a conventional vehicle stops on a horizontal road due to braking.

FIG. 5 is an explanatory diagram exaggeratingly illustrating the behavior of the vehicle body when the vehicle equipped with the stop control device according to the illustrated embodiment is stopped by braking on a horizontal road.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine 30 ... Accelerator pedal 32 ... Engine control computer 36 ... Stop control computer 40 ... Damping force control computer 42 ... Brake device 48 ... Brake pedal 52 ... Automatic brake control computer 54 ... Automatic brake device 56 ... Vehicle speed sensor 58 ... Ground body Speed sensor 60 ... Inclination angle sensor 62FL-62RR ... Stroke sensor 64 ... Brake pedal switch

Claims (6)

[Claims] 1. A means for detecting a braking state of a vehicle, a means for detecting that a vehicle body as a sprung body has substantially stopped, and a braking force applied to wheels irrespective of a braking operation by a driver as required. A vehicle stop control device comprising: a controllable braking device; and control means for substantially releasing braking force on wheels for a predetermined period of time from the moment when the sprung mass substantially stops during braking of the vehicle. 2. The vehicle has a variable damping force type shock absorber, and the control means controls the damping force of the shock absorber from a moment when the vehicle body substantially stops until at least the predetermined time elapses. The vehicle stop control device according to claim 1, wherein 3. The vehicle stop control device according to claim 1, wherein said stop control device has means for detecting a road surface inclination direction, and performs different control in accordance with the road surface inclination direction. 4. The vehicle according to claim 3, wherein the stop control device prohibits a control for substantially canceling a braking force on wheels when a road surface on which the vehicle stops is a downhill. Control device. 5. The stop control device includes a drive device capable of controlling a driving force on wheels irrespective of a driver's driving operation. When the road surface on which the vehicle stops is an uphill, the wheels do not move backward. The vehicle stop control device according to claim 3, wherein the driving device applies a driving force to wheels. 6. The suspension control device according to claim 1, further comprising means for detecting a stroke speed of the suspension, wherein the predetermined time is a time until the stroke speed of the suspension becomes substantially zero. Item 4. The vehicle stop control device according to item 1.