# US 9,517,756 B2 · Method and system for operating a motor vehicle brake system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,756 B2 - Document ID: US9517756B2 - Status: Granted - Kind: B2 - Application number: 14/594,031 - Filed: 2015-01-09 - Published: 2015-07-16 - Granted: 2016-12-13 - Earliest claimed: 2014-01-13 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies - Inventors: Thomas Svensson - Web page: https://patentgrep.com/patent/US9517756B2 ## CPC - B60T 8/171: Detecting parameters used in the regulation; Measuring values used in the regulation - B60T 8/26: characterised by producing differential braking between front and rear wheels {(using electrical circuitry or regulation means B60T8/17)} - B60T 8/266: {using valves or actuators with external control means (B60T8/261 takes precedence)} - B60T 8/268: {using the valves of an ABS, ASR or ESP system} - B60T 8/28: responsive to deceleration {(B60T8/261, B60T8/262, B60T8/266 take precedence)} - B60T 8/30: responsive to load {(B60T8/261, B60T8/262, B60T8/266 take precedence)} - B60T 2220/04: Pedal travel sensor, stroke sensor; Sensing brake request - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES ## Abstract A brake system for a motor vehicle having front and rear axles, the brake system having front and rear axle braking mechanisms operated under pressure control devices for producing a respective brake pressure on the front and rear axles of the motor vehicle. A controller receives signal information from sensors and systems on the motor vehicle to detect initiation of a braking process and detect a current speed of travel of the motor vehicle. An initial brake pressure for the rear axle braking mechanism is determined by the controller. A target brake pressure for the rear axle braking mechanism is determined by the controller and is representative of an increase in pressure relative to the initial brake pressure and the current speed of travel. Instructions from the controller operate the pressure control devices to produce the target brake pressure at the rear axle braking mechanism. ## Claims ### Claim 1 A method for operating a brake system of a motor vehicle having front and rear axles with respective front and rear axle braking mechanisms, the method carried out in a controller of the brake system, the controller having memory with stored instructions to carry out the steps of: receiving a signal indicative of initiation of a braking process; receiving a signal indicative of a current speed of travel; determining an initial brake pressure for the rear axle braking mechanism; determining a target brake pressure for the rear axle braking mechanism that is representative of an increase in pressure relative to the initial brake pressure and an increase in pressure that increases in response to a reducing current speed of travel; and subjecting the rear axle braking mechanism to the target brake pressure. ### Claim 2 (depends on 1) The method as claimed in claim 1 wherein the step of receiving the signal indicative of the current speed of travel occurs repeatedly and the target brake pressure is repeatedly determined. ### Claim 3 (depends on 1) The method as claimed in claim 1 wherein the step of receiving the signal indicative of the current speed of travel occurs continuously and the target brake pressure is continuously determined. ### Claim 4 (depends on 1) The method as claimed in claim 1 wherein the step of receiving the signal indicative of the current speed of travel occurs repeatedly and the target brake pressure is repeatedly determined. ### Claim 5 (depends on 1) The method as claimed in claim 1 wherein the step of receiving the signal indicative of the current speed of travel occurs continuously and the target brake pressure is continuously determined. ### Claim 6 (depends on 1) The method as claimed in claim 1 wherein the method further comprises the step of detecting a braking demand parameter and the increase in pressure is dependent upon the braking demand parameter. ### Claim 7 (depends on 6) The method as claimed in claim 6 further comprising the steps of: determining a target deceleration using the braking demand parameter; and the increase in pressure relative to the initial brake pressure of the rear axle braking mechanism is proportional to the target deceleration. ### Claim 8 (depends on 6) The method as claimed in claim 6 further comprising the steps of: determining a target brake pressure for the front axle braking mechanism; and subjecting the front axle braking mechanism to the target brake pressure for the front axle braking mechanism thereby reducing an initial brake pressure at the front axle to achieve the target deceleration. ### Claim 9 (depends on 6) The method as claimed in claim 6 wherein the step of detecting the braking demand parameter occurs repeatedly and the increase in pressure is repeatedly determined. ### Claim 10 (depends on 6) The method as claimed in claim 6 wherein the step of detecting the braking demand parameter occurs continuously and the increase in pressure is continuously determined. ### Claim 11 (depends on 6) The method as claimed in claim 6 wherein if the current speed of travel is greater than a predetermined maximum speed or a target deceleration exceeds a predetermined maximum deceleration, the increase in pressure for the target brake pressure for the rear axle braking mechanism is set to zero rate of increase and the rear axle braking mechanism is subject to the initial brake pressure. ### Claim 12 (depends on 1) The method as claimed in claim 1 wherein if the current speed of travel is greater than a predetermined maximum speed, the increase in pressure for the rear axle braking mechanism is set to zero rate of increase and the rear axle braking mechanism is subject to the initial brake pressure. ### Claim 13 (depends on 1) The method as claimed in claim 1 wherein if an intervention of the brake system by another system on the vehicle is taking place, the step of subjecting the rear axle braking mechanism to the target brake pressure does not take place. ### Claim 14 A brake system for a motor vehicle having front and rear axles, the brake system comprising: front and rear axle braking mechanisms operated under pressure control devices for producing a respective brake pressure on the front and rear axles of the motor vehicle; a controller to receive signal information from sensors and systems on the motor vehicle, to detect initiation of a braking process, and to detect a current speed of travel of the motor vehicle; a signal received at the controller indicative of initiation of the braking process; a signal received at the controller indicative of the current speed of travel; an initial brake pressure for the rear axle braking mechanism as determined by the controller; a target brake pressure for the rear axle braking mechanism that is determined by the controller to be representative of an increase in pressure relative to the initial brake pressure that increases in response to a reduction in the current speed of travel; and instructions from a memory of the controller to operate the pressure control devices to produce the target brake pressure at the rear axle braking mechanism. ### Claim 15 (depends on 14) The system as claimed in claim 14 further comprising a signal received at the controller indicative of a braking demand parameter and the controller using the braking demand parameter to determine the increase in pressure. ### Claim 16 (depends on 15) The system as claimed in claim 15 further comprising a target deceleration determined by the controller using the braking demand parameter, the increase in pressure relative to the initial brake pressure of the rear axle braking mechanism is proportional to the target deceleration. ### Claim 17 The system as claimed in 16 further comprising a target brake pressure for the front axle braking mechanism that is determined by the controller in order to achieve the target deceleration. ### Claim 18 (depends on 16) The system as claimed in claim 16 wherein if the current speed of travel exceeds a predetermined maximum speed or the target deceleration exceeds a predetermined maximum deceleration, then the increase in pressure is set to zero rate of increase and the rear axle braking mechanism is subjected to the initial brake pressure. ### Claim 19 (depends on 16) The system as claimed in claim 16 wherein if an intervention of another vehicle system is taking place in the braking system then the target brake pressure is not produced at the rear axle braking mechanism. ### Claim 20 (depends on 15) The system as claimed in claim 15 wherein the braking demand parameter is continuously updated in the controller and the target brake pressure is continuously updated. ### Claim 21 (depends on 14) The system as claimed in claim 14 wherein the current speed of travel is continuously updated in the controller and the target brake pressure is continuously updated. ### Claim 22 (depends on 14) The system as claimed in claim 14 wherein if the current speed of travel exceeds a predetermined maximum speed then the controller sets the increase in pressure to zero rate of increase and the rear axle braking mechanism is subjected to the initial brake pressure. ### Claim 23 (depends on 14) The system as claimed in claim 14 wherein if an intervention of another vehicle system is taking place in the braking system then the target brake pressure is not produced at the rear axle braking mechanism.