Brake control device

• US 8,914,208 B2
• Filed: 05/18/2011
• Issued: 12/16/2014
• Est. Priority Date: 05/18/2010
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.), DENSO Corporation
• Original Assignee: Advics Company Limited (Aisin Corp.), DENSO Corporation
• Inventors: Maruyama, Masaki, Takeda, Masayoshi, Tokumochi, Daisuke, Fujiki, Koji
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): BERNS, MICHAEL ANDREW
• Application Number:
  US13/698,496
• Publication Number:
  US 20130060433A1
• Time in Patent Office: 1,308 Days
• Field of Search: 701/53, 701/54, 701/70, 701/74, 701/87
• US Class Current: 701/53
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 7/122 for locking of reverse movement
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 30/18118 Hill holding

Abstract

When the vehicle decelerates on the ascending slope, a required brake axle torque is calculated in accordance with vehicle deceleration, so that the swinging back is suppressed. At start timing after that, initial and final values of the required brake axle torque and a correction duration are determined. During the correction duration from the start timing, the required brake axle torque is decreased from the initial value to the final value. Then, based on change in a detected vehicular speed at or before a time which is a last moment of a period in which the detected vehicular speed detected based on detection signals of the wheel speed sensors are equal to or larger than a minimum detectable vehicular speed, a stop time at which an actual vehicle speed becomes zero is estimated, a period from the start time to the stop time is identified as the correction duration.

Claims

1. A brake control device for a vehicle having a wheel speed sensor, comprising:

a first means for calculating a required brake axle torque being an axle torque required to brake of the vehicle, wherein a microcomputer serves as the first means;

a second means for causing a brake device of the vehicle to generate a brake pressure corresponding to the required brake axle torque calculated by the first means, wherein a microcomputer serves as the second means,

wherein the first means;

calculates the required brake axle torque so that the required brake axle torque comes closer to zero in accordance with deceleration of the vehicle when the vehicle decelerates on an ascending slope; and

at a start timing after calculating the required brake axle torque, determines a final value which is farther apart from zero than the initial value is, and a correction duration, and causing the required brake axle torque to change from the initial value to the final value during the correction duration from the start timing, wherein;

the final value is a torque with which the vehicle can stop at the ascending slope; and

the correction duration is a period from a limit time to a stop time, the limit time being a last moment of a period in which the detected vehicular speed of the vehicle detected based on a detection signal of the wheel speed sensor is equal to or larger than a minimum detectable vehicular speed, the stop time being a time at which an actual speed of the vehicle becomes zero, and the stop time being estimated based on change in a detected vehicular speed at or before the limit time.

2. The brake control device according to claim 1, wherein the start timing is a timing at which the speed of the vehicle on the ascending slope becomes smaller than the minimum detectable vehicular speed.

3. A brake control device installed to a vehicle, comprising:

a target acceleration setting portion for determining a target acceleration which the vehicle should achieve, wherein a microcomputer serves as the target acceleration setting portion; and

a braking/driving cooperative control portion for calculating, based on the target acceleration determined by the target acceleration setting portion, a required powertrain axle torque required to power the vehicle and a required brake axle torque required to brake the vehicle, transmitting the calculated required powertrain axle torque to a powertrain axle torque realizing portion which performs control so that the powertrain of the vehicle generates the required powertrain axle torque, and transmitting the calculated required brake axle torque to a brake axle torque realizing portion which performs control so that a brake device of the vehicle generates a brake pressure corresponding to the required brake axle torque, wherein a microcomputer serves as the braking/driving cooperative control portion, wherein;

a microcomputer serves as the powertrain axle torque realizing portion,

a microcomputer serves as the brake axle torque realizing portion,

the target acceleration setting portion calculates, when a speed of the vehicle on an ascending slope decreases to become equal to or smaller than a border vehicular speed, a negative soft acceleration which comes closer to zero in accordance with deceleration of the vehicle, identifies the calculated soft acceleration as the target acceleration, and keeps the soft acceleration constant after the vehicular speed becomes smaller than a minimum detectable vehicular speed of the wheel speed sensor;

the braking/driving cooperative control portion determines, at a timing at which the speed of the vehicle on the ascending slope becomes smaller than a minimum detectable vehicular speed of the wheel speed sensor, a negative initial value of the required brake axle torque, a negative final value, and a correction duration, and causes the required brake axle torque to change from the initial value to the final value during the correction duration from the timing;

the initial value is a required brake axle torque determined based on the target acceleration;

the final value is a torque with which the vehicle can stop at the ascending slope; and

the braking/driving cooperative control portion estimates a stop time at which an actual speed of the vehicle becomes zero based on a detected vehicular speed at a limit time and a detected acceleration of the vehicle calculated by the detected vehicular speed, the limit time being a last moment of a period in which the detected vehicular speed of the vehicle detected based on a detection signal of the wheel speed sensor is equal to or larger than a minimum detectable vehicular speed, and the braking/driving cooperative control portion identifies a period from the limit time to the stop time as the correction duration.