Automatic braking system for motor vehicle

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, said means for increasing the negative pressure including throttle valve control means for closing the throttle value;
• and
• a pressure sensor detecting the negative pressure in the first chamber of the booster, the throttle valve control means closing the throttle valve until the negative pressure increases to a predetermined valve so as to increase the negative pressure in the first chamber when the negative pressure detected by the pressure sensor is smaller than a second predetermined value.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, said means for increasing the negative pressure including throttle valve control means for closing the throttle valve for a predetermined time so as to increase the negative pressure in the first chamber of the booster, wherein said throttle valve control means closes the throttle valve at a speed which depends on a friction coefficient .mu. of the road surface.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, said means for increasing the negative pressure including throttle valve control means for closing the throttle valve for a predetermined time so as to increase the negative pressure in the first chamber of the booster, wherein said throttle valve control means closes the throttle valve at a speed which is dependent on a degree of opening of the throttle valve at the time of operation of the throttle valve continue means.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, wherein said negative pressure increasing means includes transmission control means for prohibiting a shift up operation of a transmission driven by said engine so as to increase the negative pressure in the first chamber of the booster.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, wherein said means for increasing the negative pressure includes throttle valve control means for closing the throttle valve completely at a predetermined time so as to increase the negative pressure in the first chamber of the booster after a condition of the throttle valve being opened has continued for a predetermined time and wherein said negative pressure increasing means includes transmission control means for shifting a transmission driven by the engine to neutral range when the throttle valve is closed completely by the throttle valve control means.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, wherein said negative pressure increasing means includes engine control means for increasing rotation speed of said engine so as to increase the negative pressure in the first chamber of the booster.

An automatic braking system for a motor vehicle having a plurality of wheels comprising:

• means for detecting a distance and a relative speed between the motor vehicle and an obstacle in front of the motor vehicle;
• judging means for judging an alarm sounding region and a region in which the vehicle has a possibility of contact with the obstacle based on the distance and the relative speed detected;
• an automatic brake for automatically braking said wheels when the judging means judges the region in which the motor vehicle has the possibility of contact with the obstacle in front of the motor vehicle, said automatic brake including a vacuum-type booster which has a first chamber, to which negative pressure is introduced, and a second chamber, to which atmospheric pressure is introduced, said first chamber being connected to a portion of an intake path of an engine downstream from a throttle valve disposed within said intake path of an engine, said booster using a pressure difference between the negative pressure and the atmospheric pressure;
• and
• means for increasing the negative pressure in the first chamber of the vacuum-type booster prior to operation of the automatic brake, wherein said means for increasing the negative pressure increases the negative pressure in the first chamber of the booster when a condition of a transmission driven by the engine is shifted to neutral range and the vehicle speed has continued to be greater than a predetermined value for a predetermined time.