Regenerative Braking Control Using Backup Sensor Inputs
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Solution Overview
Problem
Automotive Brake-By-Wire systems may fail to report brake pedal angle during braking events, leading to inadequate regenerative braking and compromised energy recovery and emission compliance.
Innovation Solution
A regenerative braking control system that utilizes brake pedal switch and/or master cylinder pressure inputs as backup signals to implement regenerative braking, ensuring proper apportionment of friction and regenerative braking even when the brake pedal angle sensor signal is unavailable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Brake Pedal Angle Sensor (BPAS) is used to measure driver braking input, then the brake system can apportion friction braking and regenerative braking, but the system may fail to report brake pedal angle during braking events leading to inadequate regenerative braking
Solution Approach 1:
The system implements a backup signal mechanism using brake pedal switch and master cylinder pressure sensor as redundant inputs. When the primary BPAS fails or does not report brake pedal angle, these backup sensors provide alternative signals to maintain regenerative braking functionality, preventing energy recovery loss due to sensor failure.
Solution Approach 2:
The brake pedal switch and master cylinder pressure sensor serve as intermediary components that translate mechanical brake pedal input into electrical signals. These intermediary sensors provide a fallback mechanism when the primary angle sensor fails, ensuring continuous operation of the regenerative braking system.
2Reliability
If the brake pedal angle sensor signal is unavailable, then the system cannot properly apportion regenerative and friction braking, but adding backup sensors increases system complexity
Solution Approach 1:
The backup sensors (brake pedal switch and master cylinder pressure sensor) serve multiple functions: they act as primary indicators of brake application and serve as fallback inputs for regenerative braking control when the BPAS fails. This multi-functionality justifies their inclusion despite increased component count.
Solution Approach 2:
The system dynamically changes the input parameter source based on BPAS availability. When BPAS signal is unavailable, the control system switches from using brake pedal angle as input to using alternative parameters from the backup sensors (pedal switch position, master cylinder pressure), maintaining system functionality without permanent complexity increase.
Data Source
AI summary
A vehicle regenerative braking control system includes a brake pedal; a brake pedal angle sensor interfacing with the brake pedal; a vehicle braking system interfacing with the brake pedal angle sensor, the vehicle braking system adapted to implement friction braking and regenerative braking responsive to receiving a brake pedal angle input signal from the brake pedal angle sensor; and at least one of a brake pedal switch and a brake master cylinder pressure sensor interfacing with the brake pedal and the vehicle braking system. The vehicle braking system is further adapted to implement friction braking and regenerative braking responsive to input from the at least one of a brake pedal switch and a brake master cylinder pressure sensor in the event that the vehicle braking system does not receive the brake pedal angle input signal from the brake pedal angle sensor. A regenerative braking control method is also disclosed.