Brake Light Activation from Torque-Based Brake Detection
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Solution Overview
Problem
Brake switches in vehicles may malfunction, preventing the activation of brake lights and thus failing to provide visual indications of braking events to other vehicles and pedestrians.
Innovation Solution
An electronic control unit in the vehicle receives various signal inputs, including engine torque and wheel rotation rates, to estimate wheel torque and detect a brake application indirectly, activating the brake light when a fault is detected in the brake switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brake switch is used to detect brake application, then the brake light activation is simple and direct, but the system reliability deteriorates when the brake switch malfunctions
Solution Approach 1:
The patent introduces an intermediary detection system that uses wheel speed sensors and electronic control units to indirectly detect brake applications. Instead of relying directly on the brake switch, the system monitors wheel deceleration patterns and torque changes as intermediary indicators of brake application, thereby maintaining reliability even when the brake switch fails.
Solution Approach 2:
The patent replaces the mechanical/electrical brake switch system with an electronic sensing system that uses wheel speed sensors and computational algorithms. The electronic control unit processes wheel speed data and torque information to detect brake applications, substituting the simple mechanical switch with a more complex but reliable electronic detection mechanism.
2Reliability
If indirect brake detection methods are implemented, then reliability improves when brake switches fail, but device complexity increases
Solution Approach 1:
The patent makes the electronic control unit multi-functional by having it perform both engine management functions and brake detection functions. The same control unit that manages engine operations also processes wheel speed data and torque information to detect brake applications, eliminating the need for a separate dedicated brake detection system and reducing overall complexity.
Solution Approach 2:
The system uses existing sensors and control units already present in the vehicle for other purposes (wheel speed sensors for ABS, engine torque sensors for power management) to also perform brake detection. The existing electronic control units serve themselves by adding brake detection capability to their existing functions, avoiding the need for additional dedicated components.
3Reliability
If the brake light is activated based on indirect detection, then visual indication is provided during brake switch failure, but false activation may occur
Solution Approach 1:
The system implements feedback mechanisms where the electronic control unit continuously monitors multiple parameters (wheel speed, torque, deceleration rate) and compares them against expected brake application patterns. The control unit only activates the brake light when the detected parameters match characteristic brake application signatures, providing feedback validation to prevent false activations while ensuring accurate detection.
Data Source
AI summary
Systems and methods for detecting a brake event of a vehicle. One system includes an electronic control unit configured to receive a plurality of vehicle signal inputs, wherein the plurality of vehicle signal inputs includes an engine torque, and estimate a wheel torque of a rear wheel of the vehicle based on one or more of the plurality of vehicle signal inputs. The electronic control unit is also configured to determine a difference between the estimated wheel torque and the engine torque, and, in response to the difference being negative and a fault being detected in a brake switch associated with a brake of the rear wheel, activating a brake light of the vehicle.