Utilizing the Electronic Stability Control Hydraulic Pump to Counteract Brake Pad Knock Back 2009-01-1030

This paper will explore an innovative solution for counteracting brake pad knock back. Fixed brake caliper applications have a tendency to knock the pads/pistons back into the caliper during high lateral acceleration maneuvers. Knock back causes increased brake pedal travel and even master cylinder run out in the most extreme case. A strategy is developed which uses the standard ESP sensors to deduce when knock back has likely occurred, and then runs the ABS pump to build enough pressure to re-seat the pads. External instrumentation was used to develop correlations between available ESP signals and measured knock back, and between pump behavior and measured movement of the piston. Data acquisition was conducted on numerous closed environments as well as proving out the feature on the racetrack. A method is developed to run the pump only as long as required to reseat the pads. The challenges faced during the industrialization of the feature are also detailed.