JP2999323B2 - Automatic vehicle braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a distance and a relative speed between an own vehicle and an obstacle, determines a possibility of contact from the detection result, and automatically generates a braking force. The present invention relates to an automatic braking device for a vehicle made as described above.

[0002]

2. Description of the Related Art Conventionally, as an automatic braking device for a vehicle of this type, for example, as disclosed in Japanese Patent Publication No. 39-2565 and Japanese Patent Publication No. 39-5668, an optical method or an ultrasonic wave is used. The distance and relative speed between the host vehicle and the obstacle in front are continuously detected, and the possibility of contact is determined based on the detected distance and relative speed between the host vehicle and the obstacle ahead. Judgment is made as to whether or not there is a possibility of contact, and if it is judged that there is a possibility of contact, it is known that an actuator is activated to automatically apply a brake to each wheel to prevent contact. I have.

[0003]

In the above-described conventional automatic braking device, when it is determined that there is a possibility of contact between the host vehicle and an obstacle ahead, the actuator is actuated to activate each of the wheels. Since the brake is configured to be applied automatically, the traveling speed of the own vehicle is rapidly reduced when it is determined that there is a possibility of contact. For this reason, the driver feels a strong sense of deceleration even though he / she does not depress the brake pedal, and feels a great deal of discomfort. Further, in some cases, the driver may feel a deceleration shock, and improvement is desired.

[0004] The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a vehicle which can be gently moved to the extent that there is no danger even when it is determined that the vehicle may come into contact with an obstacle ahead. An object of the present invention is to provide an automatic braking device for a vehicle that performs a deceleration operation so as not to give a driver an uncomfortable feeling.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, an automatic braking device for a vehicle according to the present invention according to the first aspect of the present invention includes a distance between an own vehicle and an obstacle. A detection means for detecting the relative speed, and a contact possibility determination for judging whether or not the own vehicle may contact the obstacle based on a distance and a relative speed between the own vehicle and the obstacle detected by the detection means. Means for automatically reducing engine output and generating engine brake when the determination means determines that there is a possibility of contact, and determining the transmission gear position of the vehicle. And an engine output reduction rate changing means for changing a reduction rate of the engine output in the engine brake automatic generation means in accordance with the gear position determined by the gear position determination means. It is a symptom.

According to a second aspect of the present invention, in the automatic braking apparatus for a vehicle according to the present invention, the engine output reduction rate changing means changes the reduction rate such that the lower the gear position, the smaller the reduction rate. It is characterized by. In addition, the automatic braking device for a vehicle according to claim 3, when the determination unit determines that there is a possibility of contact, automatically after the engine brake is generated by the engine brake automatic generation unit, The engine output reduction rate changing means further includes automatic brake application means for applying a braking force to each wheel, wherein the engine output reduction rate changing means starts applying the braking force to each wheel by the automatic brake application means. Is changed to the maximum.

According to a fourth aspect of the present invention, there is provided an automatic braking apparatus for a vehicle, wherein the own vehicle includes an automatic transmission, and the gear position determining means determines that the shift gear position is within a drive range. When the engine brake automatic generation means automatically starts the generation of the engine brake, the automatic transmission further includes a restriction means for restricting a shift-up operation of the automatic transmission.

[0008]

According to the first aspect of the present invention, even if it is determined that the own vehicle may come into contact with an obstacle ahead, the engine brake is first applied. By reducing the engine output, a gradual deceleration operation by the engine brake is executed, and the gradual deceleration operation does not give the driver an uncomfortable feeling. According to the second aspect of the present invention, when it is determined that the own vehicle may come into contact with an obstacle ahead, the lower the transmission gear position, the smaller the reduction rate of the engine output. , The sudden activation of the engine brake when the transmission gear position is set low is limited, and a gentle deceleration operation is reliably performed.

According to the third aspect of the present invention, when it is determined that the own vehicle may come into contact with an obstacle in front, the engine brake is first applied to reduce the engine output. If a slow deceleration operation is performed, and even if this deceleration operation is executed, if the possibility of contact still remains, a strong deceleration operation that applies the braking force of each wheel is executed to ensure contact. Will be avoided. In addition, when applying braking force to each wheel, by setting the engine output reduction rate to the maximum irrespective of the gear position, a stronger engine brake is generated and sufficient deceleration can be obtained. Become. Further, according to the invention described in claim 4, even when the own vehicle has an automatic transmission, when the engine brake is applied, the shift-up operation of the automatic transmission is regulated, so that the deceleration state is ensured. Will be achieved.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an automatic braking system for a vehicle according to an embodiment of the present invention; In this embodiment, the vehicle is provided with an automatic transmission. As shown in FIG. 1, a vehicle A provided with an automatic braking device 10 of this embodiment has left and right front wheels 12FL and 12FR as driven wheels and left and right rear wheels 12FL.
RL and 12RR are drive wheels. That is, after the drive torque generated by the engine 14 mounted on the front of the vehicle body passes through the automatic transmission 16, the propeller shaft 18, and the differential gear 20 sequentially, the left and right drive shafts 22L, 22R
Are transmitted to the left and right rear wheels 12RL, 12RR, respectively.

The above-described automatic transmission 16 includes a torque converter 24 and a multi-stage transmission gear mechanism 26. The shift operation in the automatic transmission 16 is executed by changing the combination of excitation and demagnetization of the plurality of solenoids 28 incorporated in the hydraulic circuit of the transmission gear mechanism 26. Further, the torque converter 24 includes a hydraulically operated lock-up clutch 30. The switching of the solenoid 32 incorporated in the hydraulic circuit of the lock-up clutch 30 between the excitation and the demagnetization causes the engagement of the lock-up clutch 30. And the release of the engagement are respectively executed.

On the other hand, the above-mentioned solenoids 28 and 32
It is connected to and controlled by an automatic transmission control unit (CAT) 33 for controlling the automatic transmission 16. This automatic transmission control unit (CA
T) 33 has a shift characteristic and a lock-up characteristic stored in advance in a known manner, so that the automatic transmission 16 can execute the shift control and the lock-up control based on these characteristics. Control. For this control, as shown in FIG. 2, the automatic transmission control unit (CAT) 33 includes a main throttle opening sensor 36 for detecting the throttle opening of the main slot valve 34, and a sub throttle valve 38. Sub-throttle opening sensor 4 for detecting opening
0 and a vehicle speed sensor 42 for detecting a vehicle speed, and a main throttle opening signal, a sub-throttle opening signal, and a vehicle speed signal are respectively inputted from these. In this embodiment, the vehicle speed sensor 4
2 is configured to calculate the current vehicle speed based on the rotation speed of the propeller shaft 18.

As shown in FIG. 1, the sub-throttle valve 38 and the main throttle valve 34 described above are sequentially provided in the intake passage 44 along the flow direction of the intake air. The throttle valve 38 is provided on the air cleaner side (not shown), and the main throttle valve 34 is provided on the engine 14 side. The main throttle valve 34 is mechanically connected to an accelerator pedal 46. The main throttle valve 34 is driven to open in accordance with the amount of depression of the accelerator pedal 46 by the driver, and the intake passage 44 is opened. In other words, the main throttle opening is set to be large. On the other hand, the sub-throttle valve 38 is
8 for driving control. The sub-throttle valve controller 48
Is connected to an automatic braking control unit (CAB) 49 which controls the control system of the automatic braking device 10 of this embodiment, and is configured to be driven and controlled by the automatic braking control unit (CAB) 49. That is, the sub-throttle valve 38 is electrically driven and controlled under the control of an automatic braking control unit (CAB) 49 via the sub-throttle valve controller 48 independently of the main throttle valve 34. I have.

That is, the automatic braking control unit (CA
B) 49, the control procedure of which will be described in detail later. Basically, regardless of the driver's depressing operation of the brake pedal 50, the brake pressure adjusting mechanism 54 provided in the brake hydraulic system 52 is operated. In addition to the basic automatic braking control, it controls the driving of an injection valve controller 58 that drives a fuel injection valve 56 irrespective of the fuel injection control based on the operating state. 48, the throttle opening of the sub-throttle valve 38 is changed and controlled. Further, the automatic transmission 16 is controlled via the automatic transmission control unit (CAT) 33 described above.
Is configured to control the speed change operation.

The automatic braking control unit (CAB) 49
In controlling the automatic transmission control unit (CAT) 33 at the time of the automatic braking control operation, the control is temporarily issued from the automatic transmission control unit (CAT) 33 to execute the control operation according to the shift gear position. After reading the running range position information and the transmission gear position information, the engine automatic braking control operation is executed in accordance with the read traveling range position information and the transmission gear position information. Note that the automatic engine braking control operation will be described later in detail.

Next, the structure of the above-described brake hydraulic system 52 and the structure of the brake pressure adjusting mechanism 54 connected to the brake hydraulic system will be described with reference to FIGS. 1 and 2, respectively. First, as shown in FIG. 1, each wheel 12FL, 12F
R, 12RL, and 12RR have brake devices 60FL,
60FR, 60RL, and 60RR are provided, respectively.
Each brake device 60FL, 60FR, 60RL, 60R
R is the corresponding wheel 12FL, 12FR, 12RL, 1
Calipers (brake cylinders) 64FL, 64FR, 64RL, 64RR which hold the brake disks 62FL, 62FR, 62RL, 62RR attached so as to rotate integrally with the 2RR and exert braking force by hydraulic pressure.
Each has. These calipers 64FL, 64F
R, 64RL, and 64RR are supplied with brake oil having a predetermined brake pressure via a brake hydraulic system 52.

That is, the brake hydraulic system 52 is connected to the brake pedal 50, and is connected to the booster 66 using a hydric booster for boosting the depressing force of the brake pedal 50, and is connected to the booster 66. Here, a boosted depressing force is transmitted, and a tandem-type master cylinder 68 for pressurizing brake oil is provided. The master cylinder 68 has a total of four discharge ports 70FL, 70
FR, 70RL, and 70RR. The brake hydraulic system 52 has four discharge ports 70FL, 70F.
R, 70RL, 70RR and caliper 64FL, 64F
R, 64RL, and 64RR, respectively, and brake oil adjusted to a predetermined brake pressure from master cylinder 68 is supplied to corresponding brake devices 60FL, 60FR, and 6FR.
Brake oil pipes 72FL, 72FR, 72RL, 72RR for supplying to 0RL and 60RR respectively are further provided.

The above-described booster 66 includes a supply pipe 74.
And the return pipe 76 are connected, and the engine oil is supplied to the booster 66 from the reservoir tank 78 via the supply pipe 74 by the drive of the pump 80, and the excess brake oil passes through the return pipe 76. It is configured to be returned to the reservoir tank 78 via the storage tank.

On the other hand, the above-described brake pressure adjusting mechanism 54
Are the brake oil pipes 72FL, 72FR, 72R
L, 72RR, automatic brake valve units 82FL, 82FR, 82RL, 82RR, and ABS.
(Anti-skid brake device) Valve unit 84F
L, 84FR, 84RL, and 84RR, respectively, and the brake oil from the master cylinder 68 is supplied to the automatic brake valve units 82FL, 82FR, 82RL, and 82RR.
Is supplied first, and then the ABS valve unit 84F
L, 84FR, 84RL, 84RR, and is supplied to brake devices 60FL, 60FR, 60RL, 60RR of the corresponding wheels 12FL, 12FR, 12RL, 12RR.

Here, the automatic brake valve units 82FL, 82FR, 82RL, 82RR and the ABS valve units 84FL, 84FR, 84RL, 84RR will be described below.
The automatic braking valve units 82FL, 82FR, 82RL, and 82RR have the same configuration, and the ABS valve units 84FL and 8FL have the same configuration.
4FR, 84RL, and 84RR are also identical, so in the following description, the automatic braking valve unit 82FL and the ABS valve unit 84FL corresponding to the left front wheel 12FL will be described as being representative, and other descriptions will be omitted. I do.

As shown in FIG. 2, the automatic brake valve unit 82FL includes a master cylinder 68 and a brake device 60.
A shutter valve 86FL capable of shutting off a communication state of a brake oil pipe 72FL that connects the brake oil pipe FL with an automatic brake valve unit 82FL and an ABS valve unit 84FL at one end of the brake oil pipe 72FL so as to bypass the shutter valve 86FL. And a pressure-increasing bypass pipe 88FL, the other end of which is connected to the master cylinder 68. The oil pressure of the brake oil supplied to the brake device 60FL is provided through the pressure-increasing bypass pipe 88FL. One end is connected to a portion of the pressure-increasing bypass pipe 88FL between one end thereof and the pressure-intensifying valve 90FL, and the other end is connected to the master so as to bypass the pressure-intensifying valve 90FL for increasing the pressure and the shutter valve 86FL described above. A bypass for pressure reduction connected to the cylinder 68 And 92FL, is interposed the vacuum bypass pipe 92FL, and a pressure reducing valve 94FL for lowering the oil pressure of the brake oil supplied to the brake device 60FL.

These three types of valves 86FL, 90F
Each of L and 94FL is constituted by an electromagnetic two-port two-position switching valve. A hydraulic pump 98FL driven by a motor 96FL is discharged to the master cylinder 68 and discharged from the hydraulic pump 98FL between the pressure increasing valve 90FL and the master cylinder 68 in the pressure increasing bypass pipe 88FL. Accumulators 100FL for storing the brake oil and maintaining the same at a constant pressure are provided on the pressure increasing valve 90FL side, respectively.

Here, the above-described shutter valve 86FL
Is in the open position, the brake pressure acts on the corresponding brake device 60FL in accordance with the depressing force of the brake pedal 50, and a normal braking operation is performed. On the other hand, when the shutter valve 86FL is in the closed position, the brake pressure from the master cylinder 68 does not act on the corresponding brake device 60FL. In this state,
With the pressure increasing valve 90FL in the open position, the pressure reducing valve 94
By switching the FL to the closed position, the brake pressure from the accumulator 100FL acts on the corresponding brake device 60FL, and the automatic braking operation is performed. By switching the pressure increasing valve 90FL to the closed position and the pressure reducing valve 94FL to the open position in this state, the brake oil is returned from the corresponding brake device 60FL, and the braking force is reduced. .

The above-mentioned three valves 86FL, 90F
The switching operation between L and 94FL is executed by actuators (not shown) connected to each other, and these actuators are driven and controlled based on a control signal from an automatic braking control unit (CAB) 49. .

On the other hand, the above-described ABS valve unit 84
FL is a shutter valve 102F including a three-port two-position switching valve interposed in the brake oil pipe 72FL.
L, and the shutter valve 102FL is connected to a traction control unit (CTR) 103 so that during braking (during normal braking by the driver depressing the brake pedal 50, and depressing the brake pedal 50). Is controlled independently of the shutter valve 102FL between the open position and the closed position, thereby adjusting the braking pressure applied to the corresponding brake device 60FL. The corresponding wheels 12FL are not locked.

The system configuration of the ABS is not described in detail because it is not directly related to the present invention. However, in addition to the above-described shutter valve 102FL, a motor-driven hydraulic pump 104FL and a pair of accumulators 106F are provided.
L, 108FL and the like. The traction control unit (CTR) 103 described above is also connected to the sub-throttle controller 48 described above, and although not described in detail, an overall control unit (to be described later) is used to adjust the engine generated torque during traction control. The opening and closing of the sub-throttle valve 38 is controlled via a (TCU) 113.

The traction control unit (C
TR) 103 is connected to the above-described main throttle opening sensor 36, sub-throttle opening sensor 40, and vehicle speed sensor 42, and is also provided with an accelerator opening sensor 110 for detecting the amount of depression of accelerator pedal 46. When,
Wheel rotation speed sensors 112FL, 112 for detecting the rotation speed of each wheel 12FL, 12FR, 12RL, 12RR.
FR, 112RL, 112RR (shown in FIG. 1) and a road surface μ sensor 114 for detecting a road surface friction coefficient are connected, and from these, a main throttle opening signal, a sub throttle opening signal, and a vehicle speed signal. , Accelerator opening signal, and wheels 12FL, 12FR, 12RL, 12RR
The rotation speed signal and the road surface friction coefficient signal are respectively inputted. Then, the traction control unit (CTR) controls each of the wheels 12FL, 12FR, 12R.
The slip state of the wheel is detected based on the rotation speed signals of L and 12RR, and a predetermined traction is determined according to a main throttle opening signal, a sub throttle opening signal, a vehicle speed signal, an accelerator opening signal, and a road surface friction coefficient signal. The control is executed.

Here, the traction control unit (CR
T) The main throttle opening signal, the sub throttle opening signal, the vehicle speed signal, the accelerator opening signal,
The rotation speed signals of the wheels 12FL, 12FR, 12RL, 12RR, the road surface friction coefficient signal, and the like are transmitted to the overall control unit (TCU) 113, which will be described later, and then transmitted to the automatic braking control unit (CAB) 49. It is made to be.

The automatic transmission control unit (C
The AT) 33, the automatic braking control unit (CAB) 49, and the traction control unit (CTR) 103 are connected to a total control unit (TCU) 113. The adjustment is appropriately controlled. That is, the total control unit (TCU) is connected to the injection valve controller 58, and drives the injection valve controller 58 so that the fuel injection amount optimal for the current operation state is injected from the fuel injection valve 56. The basic control operation for controlling is executed. On the other hand, this total control unit (TCU)
In addition to executing this basic control operation, the automatic braking control unit (CAB) 49, which will be described in detail later, automatically determines when the relative relationship with the obstacle in front has fallen into a predetermined dangerous state. Braking control unit (CA
Based on the command (interrupt start signal) from B), the automatic braking control operation is interrupted for the basic control operation, and the automatic transmission control unit (CAT) is also interrupted for the automatic transmission control operation. It is configured as follows.

Here, the forward obstacle refers to an object existing immediately before the own vehicle, and the same lane as the lane on which the own vehicle runs is directed in the same direction (that is, toward the front). It refers to vehicles that travel in the same lane toward their own vehicles, vehicles that stop in the same lane, and objects other than vehicles. If, for example, another vehicle enters the traveling lane of the own vehicle from the side road, the vehicle is updated so that the entering vehicle is recognized as an obstacle ahead of the own vehicle.

Next, referring to FIG. 3, a detecting mechanism 11 for detecting the distance between the host vehicle and the obstacle ahead and the relative speed between them.
6 will be described. That is, the detection mechanism 116 includes an ultrasonic radar unit 118 provided at the front of the vehicle body. Although not shown in detail, the ultrasonic radar unit 118 transmits an ultrasonic wave from an ultrasonic transmitting unit to a forward obstacle such as a vehicle located in front of the own vehicle, as is well known, The ultrasonic receiving unit is configured to receive the reflected ultrasonic waves reflected on the obstacle ahead of the vehicle. The arithmetic unit 120 is connected to the ultrasonic radar unit 118. This arithmetic unit 12
0 is the distance between the host vehicle and the obstacle ahead of the vehicle and the relative distance between the two based on the delay time (Doppler shift) from the transmission time of the ultrasonic radar reception wave in response to the detection result from the ultrasonic radar unit 118. It is configured to calculate the speed.

On the other hand, the above-described detection mechanism 116 has a pair of laser radar units 122 and 124 provided respectively on the left and right of the front part of the vehicle body. Each of the laser radar units 122 and 124 transmits a pulse laser beam having a predetermined wavelength from a laser transmitting unit, and receives a reflected laser beam reflected by the above-mentioned obstacle in a forward direction by a laser beam receiving unit. It is configured. Each of the laser radar units 122 and 124 is connected to the above-described arithmetic unit 120 via a signal processing unit 126. The arithmetic unit 120 is connected to the own vehicle based on a delay time from the transmission time of the received laser light. It is configured to calculate the distance to the obstacle and the relative speed of both.

The calculation unit 120 basically uses the calculation results of the distance and the relative speed by the system of the pair of laser radar units 122 and 124, and the distance between the obstacle and the front obstacle is equal to or less than a predetermined distance ( For example, when the distance is about 10 m or less, or when the transmitted laser light is scattered and the detection accuracy is not guaranteed in a bad weather condition such as fog, the distance by the system of the ultrasonic radar unit 118 is And the calculation result of the relative speed is used.

Each of the above-described laser radar units 122,
Reference numeral 124 is provided so as to be able to change the transmission direction of each laser light in a horizontal plane in a synchronized state. A drive motor 128 is mounted to move and drive each of the laser radar units 122 and 124 in the horizontal plane. ing. The operation unit 120 described above is connected to the drive motor 128, and the operation of the drive motor 128 is executed by the operation unit 120. On the other hand, the drive motor 128 is provided with an angle sensor 130 for detecting the drive rotation angle. The angle sensor 130 is connected to the arithmetic unit 120. The arithmetic unit 120 is provided with the angle sensor 13
Based on the detection result from 0, each laser radar unit 1
The transmission and reception directions of the laser light in the laser transmissions 22 and 124 can be detected. That is, the arithmetic unit 1
The calculation of the distance and the relative speed in the system of the laser radar units 122 and 124 by 20 is made so as to take into account the transmitting and receiving directions of the pulse laser light.

The arithmetic unit 120 is connected to the above-described automatic braking control unit (CAB) 49, where
It outputs the information on the distance between the vehicle and the obstacle ahead and the information on the relative speed between the two as the calculation result. The automatic braking control unit (CAB) 49 includes, as described above with reference to FIG. 1, the automatic braking control mechanism 54, more specifically, the automatic braking provided for each of the wheels 12 FL, 12 FR, 12 RL, and 12 RR. The valve unit 82FL,
82FR, 82RL, and 82RR, and connected to the sub-throttle valve controller 48, the injection valve controller 58, and the automatic transmission control unit (CAT) via the total control unit (TCU) 113, Based on the result, the automatic braking control operation is performed according to a control procedure described later.

The automatic braking control unit (CAB) 49
As shown in FIG. 3, based on distance information between the vehicle at the input location and the obstacle in front, a distance display panel 132 for displaying the information and the relative relationship between the obstacle and the front obstacle are dangerous. An alarm buzzer 13 that issues an alarm when it is determined to be in a state
3 are connected to each other.
Both the alarm buzzer 2 and the alarm buzzer 134 are provided in an alarm display unit 136 attached to an instrument panel (not shown) in the vehicle interior. With these arrangements, the driver can recognize the distance between the obstacle ahead and the own vehicle from the numerical value displayed on the separation distance display panel 132, and the driver can pay attention to the obstacle ahead. Even in the case where the distance between the obstacle in front and the own vehicle falls into a predetermined dangerous state, the alarm buzzer 133 sounds so that the relationship with the obstacle in front is determined by the predetermined distance. It is possible to recognize that there is a danger.

Next, a control procedure of an automatic braking control operation in the automatic braking control unit (CAB) will be described with reference to FIGS. First, as shown in FIG. 4, at a predetermined start timing, an automatic braking control operation for preventing contact with a forward obstacle is started. Here, in this embodiment, as apparent from the above description, the brake hydraulic system 5
2, the automatic brake valve units 82FL, 82FR, 8
Since the 2RL and 82RR are arranged in series with the traction control ABS valve units 84FL, 84FR, 84RL and 84RR, respectively, the automatic braking control operation is performed in order to balance the operations of both. As in the case of the traction control operation, it is set to be repeatedly started at a cycle of, for example, 7 msec.

That is, when the automatic braking control operation is started, first, in step S10, an operation of reading various input information necessary to execute the automatic braking operation is performed. The input information includes the operation unit 120
In addition to the information on the distance Lx between the vehicle and the obstacle in front of the vehicle at the location calculated in the above, the relative speed information Vx between them, the road surface μ sensor 11 via the overall control unit (TCU) 113
4 and road range coefficient information RI and transmission gear position information GI from an automatic transmission control unit (CAT).

Thereafter, in step S12, based on the various information read in step S10, various thresholds L ₀ , L ₀ ′, necessary for executing the automatic braking control operation.
L ₁ L ₁ , L ₂ , L ₂ ′ are set. Here, all thresholds are represented as distances, and in particular, the threshold L ₀
Indicates a value that is a criterion for starting the application of the braking force based on the brake hydraulic system 52 during the automatic braking operation in order to prevent the vehicle from contacting the obstacle ahead.
Also, the threshold value L ₀ ′ indicates a value that is a reference for starting the application of the braking force based on the engine brake during the automatic braking operation in order to prevent the vehicle from contacting the obstacle ahead of the vehicle. ing. In this embodiment, the threshold value L ₀ ′ is defined based on the map shown in FIG. This map will be described later in detail. The threshold value L ₀ is set to be 80% of the threshold value L ₀ ′ in this embodiment.

That is, in this embodiment, as will be described later, basically, first, the braking force by the engine brake is activated, and then the braking force by the brake hydraulic system 52 is activated. . On the other hand, prior to the start of the automatic braking operation, the threshold value L ₁ is set to the above-mentioned alarm buzzer 1.
A reference value for starting an operation of issuing a warning to the driver via 34 is shown. Incidentally, the threshold value L _1, the threshold L
It is set longer than ₀ 'by a predetermined amount. That is, the threshold L ₁ is, in the practice of this automatic braking control, so that the distance between the vehicle and the front obstacle is used as a reference value for determining that it has a risk. The threshold L _2, in after the start of the automatic braking operation, the brake hydraulic system gone possibility of contact with the front obstacle 52
The threshold value L ₂ ′ indicates a reference value for canceling the automatic braking operation based on the engine brake under the same condition. Here, the threshold value L ₂ is set to 80% of the threshold L ₂ 'in this embodiment. That is, in this embodiment, as will be described later, basically, first, the braking force by the brake hydraulic system 52 is released, and then, the braking force by the engine brake is released. Note that the threshold values L ₂ and L ₂ ′ are
The length is set to be longer by a predetermined amount than each of the thresholds L ₀ and L ₀ ′.

That is, in this embodiment, the thresholds are set in a magnitude relation represented by the following inequality: L ₂ ′> L ₂ > L ₀ ′> L ₀ L ₁ > L ₀ ′

Here, the procedure for determining the threshold value L ₀ 'will be described with reference to FIG. First, the line A in FIG.
Indicates a first threshold line, and the first threshold line A is
Front obstacle serving vehicle, when the vehicle stops in contact with the front obstacle of the vehicle, shows the following distance required to prevent the vehicle is in contact with the vehicle, the relative speed V _x regardless of the size, always, when the front obstacle is a stationary object (i.e., the relative when the speed V _x is the same as the traveling speed V ₀ which the vehicle) the same next-in numeric expression V ₀ ^2/2 [mu] g Take the numerical value to be expressed. In addition, a line B in FIG. 5 indicates a second threshold line, and the second threshold line B is used to prevent a vehicle that is an obstacle ahead from coming into contact with the vehicle when the vehicle is fully braked. , The required inter-vehicle distance, and a numerical expression V _x · (2V ₀ −
V _x ) / 2 μg.

On the other hand, a line C in FIG. 5 indicates a third threshold line, and the third threshold line C indicates that when a vehicle which is an obstacle ahead of the vehicle performs gentle braking with a deceleration μ / 2 g, The distance between vehicles required to prevent contact with the vehicle is shown.
Further, a line D in FIG. 5 indicates a fourth threshold line,
The fourth threshold line D indicates an inter-vehicle distance required to prevent contact with a preceding vehicle when the preceding vehicle maintains a constant vehicle speed. The fourth threshold line D represents a numerical value represented by a numerical expression V _x / 2 μg. Take. In addition, the line E in FIG. 5 indicates a threshold line, and the 'threshold line E' does not prevent the vehicle from contacting the vehicle that is the obstacle ahead of the vehicle even when the vehicle is automatically braked. It shows the distance between vehicles that can alleviate the impact force to some extent. In this embodiment, the threshold is assumed that the second threshold line B via the mode switching switch (not shown) is selected by using the second threshold line B, corresponding to the relative velocity V _x at the present time L ₀ ′ is required.

As described above, after various threshold values L ₀ , L ₀ ′, L ₁ L ₁ , L ₂ , L ₂ ′ are set in step S 12, in step S 14, the own vehicle and the obstacle ahead are determined. whether the relative velocity V _x between is 0 or more is determined. Here, in this embodiment, the relative speed V _x
Indicates a state where they are close to each other when a positive value is taken, and indicates a state where they are separated from each other when a negative value is taken. This step S
If YES is determined at 14, i.e., if the relative speed V _x is determined to be in a state where both take a positive value are close to each other, since the automatic activation routine of the braking force is performed.

That is, in the following step S16,
The distance between the vehicle and the front obstacle (hereinafter, simply referred to as distance.) L _x whether less than a threshold value L ₁ described above is determined. If NO is determined in step S16, i.e., in the range of distance L _x is defined by the inequality L _x ≧ L _1, not reached the region defining the still hazardous condition, the alarm buzzer 134 When it is determined that it is not necessary to perform the ringing, the automatic braking control operation does not have to be performed. Therefore, the control procedure is terminated without executing the automatic activation routine of the braking force, and after 7 msec. Wait for the next set control procedure to start.

On the other hand, in step S16, YES
Is determined, that is, the separation distance is an inequality L _x <L ₁
If it is determined that the vehicle is in the danger state, the process proceeds to step S18, and the alarm buzzer 13
4 is ringing and notifies that the distance L _x of the front obstacle to the driver falls into critical condition. Thereafter, step S2
Distance L _x is in the 0 whether less than a threshold value L ₀ 'is determined. If NO is determined in step S20, i.e., the distance L _x inequality L ₀ '≦ L
It is within the range defined by _x <L _1, although there are necessary to continue the alarm action, when it until performing automatic braking operation is determined not to end the current control procedures, Wait for the next control procedure set after 7 msec.

Here, if YES is determined in the step S20, that is, if the separation distance L _x is equal to the inequality L _x <L
_If it is within the range defined by ₀ 'and it is determined that the automatic braking operation needs to be performed, the process proceeds to step S22, in which the engine 14 generates an engine brake, and the braking force by the engine brake is activated. In order to perform this, an interrupt start signal is output to the total control unit (TCU) 113, and the engine automatic braking control defined as an interrupt routine is started here. The control procedure of the engine automatic braking control will be described later in detail.

[0048] The after starting the engine automatic brake control in step S22, in step S24 subsequent, whether the distance L _x is smaller than the threshold value L ₀ is determined. If NO is determined in step S24, i.e., the distance L _x inequality L ₀ ≦ L _x <L
_If it is within the range defined by ₀ 'and it is determined that sufficient braking force is applied as a danger avoidance operation only by the braking force by the engine brake, the control procedure is terminated, and after 7 msec, Wait for the next set control procedure to start.

On the other hand, in step S24 described above, Y
If it is determined as ES, that is, the separation distance L _x is equal to the inequality L
_When it is determined that _x is within the range defined by L < ₀ and a strong braking force is required, the process proceeds to step S26,
A brake automatic braking control operation by the brake hydraulic system 52 defined as an interruption routine is started. still,
The control procedure of this automatic braking operation will be described later in detail. Then, in step S28, the flag F indicating that the brake automatic braking control operation is being performed is set to "1", and the next control procedure set after 7 msec is waited for activation.

The automatic brake control operation in step S26 is executed as an interrupt routine independent of the main routine. Once activated, the control operation is executed unless a corresponding release operation is executed. It is set to continue. On the other hand, if NO is determined in step S14 described above, that is,
The relative velocity V _x is determined to be a negative value, when the front obstacle is determined to be gradually away from the vehicle, the automatic release routine of the braking force is performed. That is, first proceeds to step S30, where whether or not the distance L _x is greater than the threshold value L ₂ is determined. This step S
30 is NO, that is, the separation distance L
_{If x} is within the range defined by the inequality L _x ≦ L ₂ and it is still determined that the relationship with the obstacle ahead is in danger and the automatic braking control operation needs to be continued, This control procedure is terminated without specifically executing the automatic power release routine, and the next control procedure set after 7 msec is started. That is, this step S3
Even if it is determined to be NO at 0, the engine automatic braking control is activated in advance in step S22 or step S26, or if the automatic braking control is activated, these are continuously executed. Become.

In step S30 described above, Y
If it is determined as ES, that is, the separation distance L _x is equal to the inequality L
_x > L ₂ , and the brake hydraulic system 5
When it is determined that the braking force by No. 2 is unnecessary, the process proceeds to step S32, where a brake automatic braking control release signal is output to release the brake automatic braking control operation in the brake hydraulic system 52. Thereafter, the process proceeds to step S34, where the flag F indicating that the automatic braking control operation is being performed is reset to "0".
Indicates that the automatic braking control operation has been released.
Then, in step S36, whether the distance L _x is greater than the threshold value L ₂ 'is determined. If NO is determined in this step S36, i.e., in the range of distance L _x is defined by the inequality _{L 2 <L x ≦ L 2} ', still at risk the relationship between the front obstacle However, if it is determined that a strong braking force by the brake hydraulic system 52 is unnecessary, but it is determined that the engine automatic braking control operation needs to be continued, the current control procedure is terminated and set after 7 msec. Wait for the next control procedure to be started.

On the other hand, in step S36 described above, Y
If it is determined as ES, that is, the separation distance L _x is equal to the inequality L
_When it is determined that _x > L ₂ ′ and the braking force by the engine brake is unnecessary,
In step S38, an automatic engine braking control release signal is output to the overall control unit (TCU) 113 to release the automatic engine braking control operation. Upon receiving this engine automatic braking control release signal, the overall control unit (TCU) 113 stops the closing operation of the sub-throttle valve 38 via the sub-throttle valve controller 48 and returns it to the fully open state. Thereafter, the process proceeds to step S40, in which an alarm operation canceling signal for canceling the alarm operation is output, that is, the sounding operation of the alarm buzzer 134 is stopped, and a series of control procedures is terminated, and the process proceeds to 7msec.
It waits for the next set control procedure to be activated later. Thus, a series of procedures of the automatic braking control operation is completed.

Next, referring to FIG. 6, the control procedure of the automatic engine braking control operation in step S22 described above will be described as an interrupt routine in the overall control unit (TCU) 113. First, when the automatic engine braking control operation is started in step S22, it is determined in step S22A whether or not the flag F indicating that the automatic braking control is activated is set to "1". In this step S22A, N
When it is determined as O, that is, when it is determined that the automatic brake braking control has not been activated in advance, the engine brake control amount EBC according to the current travel range position or the shift gear position (described later in detail). .) Is executed.

That is, in the following step S22B, the travel range position currently set in the automatic transmission 16 is determined based on the travel range position information RI read in advance in step S10. This step S2
2B, the travel range position currently set in the automatic transmission 16 is “L” (that is, the shift gear position is 1).
(Fixed to speed), if it is determined that the
In 2C, the engine brake control amount EBC is set to a minimum value (MIN). Then, the subsequent step S2
In 2D, this minimum engine brake control amount EB
At C, the sub-throttle valve 38 is closed and driven via the sub-throttle valve controller 48. Here, by setting the minimum engine brake control amount EBC, the sub-throttle valve controller 48 activates the engine brake gradually so that the intake passage 44 is closed at a gentle closing speed. Like sub throttle valve 3
8 is driven.

On the other hand, in the above-described step S22B, the currently set traveling range position of the automatic transmission 16 is "S" (that is, the transmission gear position is the first or second gear).
If it is determined that the speed is set to (speed), the process proceeds to step S2.
In 2E, the engine brake control amount EBC is set to an intermediate value (MED). Then, the above-described step S2
Proceeding to 2D, this intermediate engine brake control amount EBC
Then, the sub-throttle valve 38 is closed and driven via the sub-throttle valve controller 48. Here, when the intermediate value of the engine brake control amount EBC is set, the sub-throttle valve controller 48 drives the sub-throttle valve 38 so that the intake passage 44 is closed at a normal (medium) closing speed.

Further, in step S22B described above, it is determined that the currently set traveling range position of the automatic transmission 16 is "D" (that is, the transmission gear position is set to an arbitrary position that is optimal for the traveling state). If so,
In step S22F, the one-way clutch (not shown) of the automatic transmission 16 is fixed in order to prohibit the upshifting operation in the automatic transmission 16, in other words, to keep the current transmission gear position constant. That is, when the intake passage 44 is closed in the drive range "D", the vehicle normally operates by the action of the one-way clutch.
It becomes an inertial running state. In this inertial running state, the driver has a feeling of anxiety such as being pulled forward. However, by fixing the one-way clutch in step S22F, the current shift gear position is fixed, the engine brake is reliably activated, and anxiety that the driver is pulled forward can be eliminated. Becomes

Then, in the subsequent step S22G, it is determined where the current shift gear position is based on the shift gear position information GI read in advance in step S10. That is, if it is determined in step S22G that the transmission gear position is set to “first speed”, the process proceeds to step S22C, where the engine brake control amount EBC is set to the minimum value (MIN). Proceeding to S22D, the sub-throttle valve 38 is gradually closed and driven with the minimum engine brake control amount EBC. On the other hand, if it is determined in step S22G that the transmission gear position is set to "second speed", the process proceeds to step S22E, where the engine brake control amount EBC is set to an intermediate value (MED). S22D
The sub-throttle valve 38 is closed at the normal closing speed with the intermediate engine brake control amount EBC.

On the other hand, if it is determined in step S22G that the transmission gear position is set to "third speed" or "fourth speed" (including overtopping), then in step S22H, the engine brake control is executed. The amount EBC is set to the maximum value (MAX), and thereafter, the process proceeds to step S22D described above, and the sub-throttle valve 38 is rapidly closed and driven with the maximum engine brake control amount EBC.

Here, if it is determined YES in step S22A described above, that is, if it is determined that the automatic brake braking control has been activated, regardless of the current travel range position or the transmission gear position. Then, a control procedure for setting the engine brake control amount EBC to the maximum value is executed. That is, if YES is determined in step S22A, the process immediately jumps to step S22H, sets the engine brake control amount EBC to the maximum value (MAX), and rapidly sets the sub-throttle valve 38 regardless of the shift gear position. When the engine is closed, the engine brake is strongly activated. That is, by activating such a powerful engine brake simultaneously with the automatic braking control, the vehicle is decelerated with an extremely strong braking force as a whole, so that a reliable danger avoiding operation is achieved.

As described above, in step S22D,
When the operation of closing and driving the sub-throttle valve 38 with the predetermined engine brake control amount EBC is executed, it is determined in a succeeding step S221 whether or not the engine automatic braking control release signal is output. If NO is determined in step S221, that is, if it is determined that the engine automatic braking control release signal has not been output without executing step S38 described above,
Returning to step S22A, the automatic engine braking control is started again. On the other hand, if YES is determined in step S221, that is, if it is determined in step S38 that the engine automatic braking control release signal has been output, the engine automatic braking control operation is terminated, and The control procedure of the engine automatic braking control ends.

Next, referring to FIG. 7, the control procedure of the automatic braking control operation in step S26 will be described as an interrupt routine in the automatic braking control unit (CAB). First, before the brake automatic braking control operation is performed, the automatic braking valve units 82FL, 82FR, 8
2RL and 82RR shutter valves 86FL and 8 respectively
6FR, 86RL, 86RR are all in the open state,
Further, the pressure increasing valves 90FL, 90FR, 90RL, 90
RR and pressure reducing valve 94FL, 94FR, 94RL, 94
Both RRs are in a closed state. In this manner, the brake pressure generated in the master cylinder 68 due to the depression of the brake pedal 50 is applied to each of the wheels 12FL, 12FR, 1
A manual braking operation can be executed by acting on the 2RL and the 12RR.

When the automatic brake control operation is started in step S26 from the state before the automatic brake control operation is performed, in step S26A, the automatic brake valve units 82FL and 82FL of the brake pressure adjusting mechanism 54 are operated. The shutter valves 86FL, 86FR, 86RL of 82FR, 82RL, 82RR, respectively.
86RR is closed and driven. As a result, the brake pressure due to the depression of the brake pedal 50 is increased for each wheel 12FL,
12FR, 12RL, 12RR brake device 60F
L, 60FR, 60RL, and 60RR are incapable of acting, in other words, thereby, the automatic brake control operation is enabled.

Thereafter, in step S26B, it is determined whether or not the brake pressure acting on the brake devices 60FL, 60FR, 60RL, 60RR of the wheels 12FL, 12FR, 12RL, 12RR has reached a predetermined pressure. If NO is determined in this step S26B, that is, the brake devices 60FL, 60FR, 6
If it is determined that the brake pressure acting on 0RL and 60RR is insufficient, the pressure-intensifying valves 90FL, 90FR, 90RL, and 90RR are driven to open in step S26C, and the pressure-reducing valves 94FL and 94FR in subsequent step S26D. , 94RL, and 94RR are driven to close. As a result, accumulator 100FR, 1
The brake pressure accumulated in 00FR, 100RL, and 100RR is changed to each wheel 12FL, 12FR, 12RL, 1
2RR brake devices 60FL, 60FR, 60RL,
By acting on 60RR, a predetermined braking operation is executed.

On the other hand, if YES is determined in the above-described step S26B, that is,
If it is determined that the brake pressure acting on 0FL, 60FR, 60RL, and 60RR is sufficient, step S
At 26E, the pressure increasing valves 90FL, 90FR, 90
RL and 90RR are driven to close, and the following step S2
6F, pressure reducing valves 94FL, 94FR, 94R
L and 94RR are driven to open. As a result, the accumulators 100FR, 100FR, 100RL, 100RR
The brake pressure stored in the brake device 60FL,
It does not act on 60FR, 60RL, 60RR, and conversely, brake devices 60FL, 60FR, 60RL, 60
The brake pressure of the RR is reduced by the pressure reducing valves 94FL, 94FR, 9
It will be reduced via 4RL and 94RR.

By repeating such a control procedure, the brake pressure acting on the brake devices 60FL, 60FR, 60RL, 60RR of the wheels 12FL, 12FR, 12RL, 12RR is maintained at a predetermined value regardless of the depression of the brake pedal 50. The value will be kept constant. On the other hand, when the above-described step S26D or step S26F is executed, the process proceeds to step S26G, where it is determined whether or not the brake automatic braking control release signal has been output. If NO is determined in this step S26G, that is, step S32 is not executed, and
If it is determined that the brake automatic braking control release signal has not been output, the process returns to step S26B described above,
From here, the brake automatic braking control is started again. On the other hand, if YES is determined in step S26G, that is, if it is determined that the automatic brake braking control release signal is output in step S32, the automatic brake braking control operation is terminated, and The control procedure of the automatic brake braking control ends.

As described in detail above, in this embodiment, when it is determined that the relationship between the own vehicle and the obstacle ahead has entered a dangerous state, the automatic braking control is started. However, in this automatic braking control operation, first, an alarm operation is activated to notify the driver that the vehicle has entered a dangerous state with the obstacle ahead. In spite of this notifying operation, when the degree of danger to the obstacle ahead increases, first, an automatic engine braking control procedure is performed to activate the engine brake, and the speed of the own vehicle is reduced. When the engine brake is activated and the danger to the obstacle in front is further increased, and the danger of collision is increased, the automatic braking control procedure is executed to further activate the braking force by the brake device to perform full braking. To reduce the speed of the vehicle to a state where the vehicle substantially stops.

As described above, in this embodiment, in the automatic braking control, first, the engine brake is activated, and when the danger cannot be avoided only by the braking force by the engine brake, the braking force by the braking device is Is activated to apply full braking.
Even if the automatic braking control is executed in this way, initially, only a gentle braking force by the engine brake is applied, so that the driver feels less deceleration, and the driver feels discomfort, shock, or fear. Can be obtained as much as possible. Also,
If the driver receives a shock or fear due to a sudden sense of deceleration, the driver may panic and perform the wrong danger avoidance operation, which may cause another danger, but as described above,
In this embodiment, since a gentle deceleration operation is performed, there is little risk of giving a shock or fear to the driver, and there is no possibility that such another danger occurs.

Further, in the above-described embodiment, when executing the automatic engine braking control, the sub-throttle valve 38 is closed at a closing speed corresponding to the set shift gear position to change the degree of activation of the engine brake. Let me. Specifically, when the shift gear position is low, that is, in the "first speed", when the sub-throttle valve 38 is abruptly closed and driven, the engine brake is suddenly applied, giving a sudden sense of deceleration to the driver. However, in this embodiment, when it is determined that the transmission gear position is in the "first speed", the sub-throttle valve 38 is closed at the slowest closing speed. However, the driver is not given a sudden deceleration feeling.

When the transmission gear position is in the middle position, that is,
If it is determined that the vehicle is in the "second speed", the sub-throttle valve 38 is set to be closed at a normal closing speed. Further, when the transmission gear position is high, that is, "third speed"
Alternatively, if it is determined that the vehicle is in the "fourth speed", it is difficult to apply the engine brake. Therefore, the sub-throttle valve 38 is driven to close at the fastest closing speed so that the engine brake is activated effectively. Have been.

Further, in the above-described embodiment, when the automatic braking control is started to activate the braking force by the brake device, a strong braking force is required, so that the engine automatic braking is required. In the control procedure, the operation of closing the sub-throttle valve 38 at the closing speed according to the shift gear position as described above is interrupted, and the brake automatic braking control is started regardless of the shift gear position regardless of the shift gear position. The sub-throttle valve 38 is closed and driven at the fastest closing speed to activate a strong engine brake. In this way, it is possible to apply full braking in a state where the braking force of the brake device and the strong braking force of the engine brake are combined, and it is possible to effectively avoid the danger between the vehicle and a forward obstacle. Will be.

Further, in this embodiment, even when full braking is applied in this manner, the vehicle A still has ABS valve units 84FL, 84FR, 84RL, and 84RL for the wheels 12FL, 12FR, 12RL, and 12RR.
84RR, which are controlled by a traction control unit (CTR) 103 for each wheel 12FL, 12FL.
Since the FR, 12RL, and 12RR are controlled so as not to be locked, the vehicle A can be stopped in a stable state.

Further, in the above-described embodiment, when the engine automatic braking control is activated and the set traveling range is determined to be the drive range "D", the one-way clutch is locked and The currently set shift gear position is fixed, and the upshift operation is prohibited. In this manner, the vehicle A is prohibited from entering the inertial running state while the engine brake is applied, and the engine brake can be reliably activated. It is prevented from giving to the driver.

It is needless to say that the present invention is not limited to the configuration of the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, in the above-described embodiment, the vehicle A is described as including the automatic transmission 16, but the present invention is not limited to such a configuration, and will be described below as another embodiment. The present invention can also be applied to a vehicle having a manual transmission.

Referring to FIG. 8, an automatic braking control procedure in an automatic braking control unit (CAB) in a vehicle having a manual transmission will be described. In the case where the manual transmission is provided, the automatic braking control procedure is the same as that described with reference to FIG. 4 in one embodiment.
Since the control procedure of the automatic brake control in step S26 is the same, the description is omitted here. That is, FIG. 8 shows a control procedure of the engine automatic braking control in a mode different from that of the embodiment.

First, in a vehicle equipped with a manual transmission, when the automatic engine braking control operation is started, "1" is set to a flag F indicating that the automatic braking control is activated in step S22A '. It is determined whether or not it is set. If NO in step S22A ', that is, if it is determined that the automatic brake braking control has not been activated in advance, the engine brake control amount EBC corresponding to the currently set shift gear position is determined. The control procedure to be set is executed. That is,
In step S22B ', the transmission gear position information G read in advance in step S10 in the embodiment described above.
Based on I, it is determined where the current transmission gear position is. That is, if it is determined in step S22B 'that the transmission gear position is set to "first speed", the process proceeds to step S22C', where the engine brake control amount EBC is set to the minimum value (MIN). S22
Proceeding to D ', this minimum engine brake control amount EB
At C, the sub-throttle valve 38 is gently closed and driven. On the other hand, if it is determined in step S22B 'that the transmission gear position has been set to "second speed", the process proceeds to step S22E', in which the engine brake control amount EBC is set to an intermediate value (MED). Step S22D '
The sub-throttle valve 38 is closed at the normal closing speed with the intermediate engine brake control amount EBC.

On the other hand, if it is determined in step S22B 'that the transmission gear position is set to the "third speed" or "fourth speed" (including the overtop) high speed gear position, In S22F ', the engine brake control amount EBC is set to the maximum value (MAX), and thereafter, the process proceeds to step S22D', where the sub throttle valve 38 is set to the maximum engine brake control amount EBC.
Is rapidly closed.

Here, if it is determined YES in step S22A 'described above, that is, if it is determined that the automatic brake braking control has been activated, regardless of the current shift gear position, the engine brake is stopped. Control amount EBC
A control procedure to set to the maximum value. That is, if YES is determined in the step S22A ', the process immediately jumps to the step S22F' and the engine brake control amount EB
By setting C to the maximum value (MAX), the sub-throttle valve 38 is rapidly closed and driven regardless of the position of the transmission gear to strongly activate the engine brake. That is, by activating such a powerful engine brake simultaneously with the automatic braking control, the vehicle can be decelerated with an extremely strong braking force as a whole.

As described above, in step S22D ', when the sub-throttle valve 38 is driven to close with a predetermined engine brake control amount EBC, it is determined in subsequent step S22G' whether an automatic engine braking control release signal is output. You. If NO is determined in this step S22G ', that is, if it is determined that the engine automatic braking control release signal is not output without executing step S38 in the above-described embodiment, the above-described step is performed. Returning to S22A ', the engine automatic braking control is started again. On the other hand, this step S22
When YES is determined in G ', that is, when it is determined in step S38 that the engine automatic braking control release signal has been output, the engine automatic braking control operation is terminated, and a series of engine automatic braking control operations are performed. The control procedure of the control ends. As described in detail above, the present invention is also applicable to a vehicle having a manual transmission,
The present invention can be similarly applied to a vehicle having an automatic transmission.

In the above-described embodiment, the running range position and the transmission gear position are output from the automatic transmission control unit (CAT) 33 to the automatic transmission 16 in the running range position and the transmission gear position information. However, the present invention is not limited to such a configuration, and uses detection means for detecting a travel range position and a transmission gear position that are actually set in the automatic transmission 16. The automatic transmission 16 may be configured to recognize the currently set travel range position and transmission gear position based on the detection result of the detection means.

Further, in the above-described embodiment, various threshold values are described as being set in a relation represented by an inequality expression. However, the present invention is not limited to such a relation, and various threshold values are set. It is specified in the embodiment. For example, in one embodiment described above, the threshold L ₂ is greater than the threshold value _{L 0 (L 2> L 0} ), The threshold L2 'is the threshold L _0' is greater than _{(L 2 '> L 0'} ) Niigata explained, without being limited to this limitation, the threshold L ₂ may be the threshold L ₀ or less (L ₂ ≦ L _0), the threshold L ₂ 'is the threshold L _0' (L ₂ ′ ≦ L ₀ ′).

In the above-described embodiment, the sub-throttle valve 38 is driven to close the intake passage 44 in order to lower the engine output and generate engine braking. The present invention is not limited to such a configuration, and controls the driving of an injection valve driver 58 connected to the fuel injection valve 56 to reduce or cut off the fuel supply to the engine 14, thereby reducing the engine output. Alternatively, control may be performed such that the control of closing the intake passage 44 by the sub-throttle valve 38 and the control of decreasing the fuel injection amount by the fuel injection valve 56 are simultaneously executed. You may.
By executing both at the same time as described above, the engine brake is more reliably exerted.

In the case where the engine output is reduced by limiting the fuel injection amount to activate the engine brake, the engine brake control amount EBC
Indicates the decreasing speed of the fuel injection amount. The smaller the engine brake control amount EBC is, the slower the decreasing speed of the fuel injection amount is set, and the larger the engine braking control amount EBC is, the faster the setting is.

[0083]

As described in detail above, the automatic braking device for a vehicle according to the present invention detects the distance and the relative speed between the own vehicle and the obstacle, and detects the relative speed. From the distance and the relative speed between the own vehicle and the obstacle, a contact possibility determining means for determining whether or not the own vehicle may come into contact with the obstacle, and the determining means determines that there is a possibility of contact. In this case, the engine output is automatically reduced to generate an engine brake, an engine brake automatic generating means, a gear position determining means for determining a shift gear position of the own vehicle, and the gear position determining means are used. An engine output reduction rate changing means for changing a reduction rate of the engine output in the engine brake automatic generation means according to the gear position is provided.

Further, the automatic braking device for a vehicle according to the present invention is characterized in that the engine output reduction ratio changing means changes the reduction ratio so that the lower the gear position, the smaller the reduction ratio. Further, the automatic braking device for a vehicle according to the present invention automatically controls each wheel after the engine brake is generated by the automatic engine brake generating means when the determining means determines that there is a possibility of contact. Automatic braking means for applying a braking force, wherein the engine output reduction rate changing means maximizes the reduction rate of the engine output when the braking force is applied to each wheel by the automatic braking means. It is characterized by changing to. Further, in the automatic braking device for a vehicle according to the present invention, the self-vehicle includes an automatic transmission, and the engine position is automatically generated when the gear position determining unit determines that the shift gear position is in the drive range. When the means automatically starts the generation of the engine brake, the apparatus further comprises a regulating means for regulating a shift-up operation of the automatic transmission.

Therefore, according to the present invention, even when it is determined that the own vehicle may come into contact with the obstacle ahead, a gentle deceleration operation is performed so that the driver does not feel uncomfortable. An automatic braking device for a vehicle is provided.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram schematically showing a configuration of an embodiment of an automatic braking device for a vehicle according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing a configuration of a brake hydraulic system applied to the automatic braking device.

FIG. 3 is a block diagram showing a configuration of a detection mechanism for detecting a distance between a host vehicle and an obstacle ahead and a relative speed between the two.

FIG. 4 is a flowchart showing a control procedure of an automatic braking control operation in the automatic braking control unit.

FIG. 5 is a diagram showing a threshold setting map used in the automatic braking control operation.

FIG. 6 is a flowchart showing a control procedure of an engine automatic braking control operation.

FIG. 7 is a flowchart showing a control procedure of a brake automatic braking control operation.

FIG. 8 is a flowchart showing a control procedure of an engine automatic braking control operation applied to a vehicle having a manual transmission.

[Explanation of symbols]

 Reference Signs List A vehicle 10 automatic braking device 33 automatic transmission control unit 38 subthrottle valve 48 subthrottle valve controller 49 automatic braking control unit 54 brake pressure adjusting mechanism 60 brake device 72 brake piping, 82 automatic braking valve unit 84 ABS valve unit 116 detection mechanism It is.

Continuation of front page (56) References JP-A-59-33048 (JP, A) JP-A-59-231157 (JP, A) JP-A-3-224858 (JP, A) JP-A-2-125935 (JP) JP-A-4-219429 (JP, A) JP-A-4-11523 (JP, A) JP-A-1-257729 (JP, A) JP-A-1-160737 (JP, A) 60-135229 (JP, U) JP-A 1-127949 (JP, U) JP-B 39-2565 (JP, B1) JP-B 39-5668 (JP, B1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F02D 29/02 301 F02D 29/00

Claims (4)

(57) [Claims] A detecting means for detecting a distance and a relative speed between the own vehicle and the obstacle; and a detecting means for detecting a distance and a relative speed between the own vehicle and the obstacle detected by the detecting means. Contact possibility determining means for determining whether there is a possibility of contact with an obstacle; and when the determining means determines that there is a possibility of contact, the engine output is automatically reduced to generate an engine brake. Means for automatically generating engine brakes, gear position determining means for determining a shift gear position of the vehicle, and a gear position determined by the gear position determining means.
An automatic braking device for a vehicle, comprising: an engine output reduction ratio changing unit that changes a reduction ratio of an engine output in the engine brake automatic generation unit. 2. The automatic braking device for a vehicle according to claim 1, wherein the engine output reduction rate changing means changes the reduction rate so that the lower the gear position is, the smaller the reduction rate is. 3. An automatic brake applying means for automatically applying a braking force to each wheel after an engine brake is generated by said engine brake automatic generating means when said determining means determines that there is a possibility of contact. The engine output reduction rate changing means, when the application of the braking force to each wheel is started by the automatic brake applying means,
3. The automatic braking device for a vehicle according to claim 1, wherein the reduction rate of the engine output is changed to a maximum. 4. The self-vehicle includes an automatic transmission. When the gear position determination unit determines that the transmission gear position is within a drive range, the engine brake automatic generation unit automatically activates an engine brake. 2. The automatic transmission according to claim 1, further comprising a regulating unit that regulates a shift-up operation of the automatic transmission when the generation is started.
4. The automatic braking device for a vehicle according to 2 or 3.