Brake Clutch Sensor Diagnostics via Vehicle Dynamics
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Solution Overview
Problem
Hybrid and electric vehicles face challenges in diagnosing failures in brake and clutch systems due to limitations in existing brake pedal switch configurations, which are single-point-of-failure modes and difficult to diagnose using out-of-range, open-circuit, and short-circuit detection techniques, especially affecting energy-savings functionalities like regenerative braking and power-system shutoff.
Innovation Solution
A system comprising a brake position sensor, a clutch position sensor, and a controller with a communication module, vehicle dynamics module, and sensor diagnostics module that interprets signals and vehicle dynamics information to determine sensor failures without the need for redundant sensors, inferring sensor malfunctions based on vehicle motion and environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple switch is used as a brake pedal position sensor, then the system cost is reduced and the structure is simplified, but the reliability deteriorates due to single-point-of-failure mode and diagnostic difficulty
Solution Approach 1:
The system uses feedback from multiple sources (brake pedal position sensor, clutch position sensor, vehicle dynamics information from accelerometers and speed sensors) to continuously monitor and diagnose the operational status of discrete inputs. The controller compares expected vs. actual sensor readings to detect failures, providing continuous system self-diagnosis without adding redundant sensors.
Solution Approach 2:
The existing vehicle dynamics sensors (accelerometers, speed sensors) perform dual functions by both controlling vehicle operations and diagnosing brake/clutch sensor failures. The system uses its own operational data to self-diagnose sensor malfunctions, eliminating the need for separate diagnostic hardware.
2Difficulty of detecting and measuring
If out-of-range, open-circuit and short-circuit detection techniques are used, then some sensor failures can be detected, but the diagnostic capability deteriorates for discrete inputs like brake switches
Solution Approach 1:
The system transitions from one-dimensional electrical circuit detection (open/short circuit) to multi-dimensional diagnostic analysis by incorporating vehicle dynamics information (acceleration, speed, operational patterns). This adds temporal and contextual dimensions to failure detection, enabling diagnosis of functional failures beyond simple electrical faults.
Solution Approach 2:
The controller performs multiple functions simultaneously: it controls vehicle operations based on sensor inputs and diagnoses sensor failures using the same sensor data. The vehicle dynamics information serves dual purposes for both control and diagnostics, maximizing information utilization.
3Reliability
If redundant sensor systems are implemented, then the reliability is improved, but the system cost and complexity increase
Solution Approach 1:
The vehicle dynamics information (accelerometer data, speed sensor readings) acts as an intermediary that indirectly monitors brake and clutch sensor functionality. Instead of directly adding redundant sensors, the system uses intermediate measurements of vehicle motion to infer sensor operational status.
Solution Approach 2:
The system creates a virtual model of expected sensor behavior by comparing actual sensor readings against predicted values derived from vehicle dynamics. This virtual copying allows diagnostic comparison without physical redundancy, detecting deviations that indicate sensor failures.
Data Source
AI summary
A device includes at least one of a brake position sensor operationally coupled to a brake and providing a brake position signal, or a clutch position sensor operationally coupled to a clutch and providing a clutch position signal. The device further includes a controller having a communication module structured to interpret the at least one of the brake position signal or the clutch position signal, and a collection module structured to collect vehicle dynamics information. The controller further includes a vehicle dynamics module structured to interpret the vehicle dynamics information, and a sensor diagnostics module structured to determine a failure of at least one of the clutch position sensor or the brake position sensor in response to the vehicle dynamics information and at least one of the clutch signal or the brake signal.