Ignition Switch Signal Line Fault Detection Using CAN and SBW Signals
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Solution Overview
Problem
Existing abnormality detection devices for ignition switch signal lines require new circuits or modifications, leading to increased system costs and complexity, necessitating a more cost-effective solution.
Innovation Solution
An abnormality detection device that utilizes existing signals, including a voltage signal, a Controller Area Network (CAN) signal, and a shift-by-wire system (SBW) signal to detect abnormalities in the ignition switch signal line, without requiring additional circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a new circuit or modified existing circuit is designed to receive and control the port input signal for abnormality detection, then the abnormality detection capability is improved, but the system cost increases due to complication of control and expansion of circuit scale
Solution Approach 1:
The patent applies multi-functionality by enabling existing signals (CAN signal and SBW signal) to serve dual purposes: their original functions plus abnormality detection. The determination unit analyzes combinations of these existing signals to detect signal line abnormalities, eliminating the need for dedicated detection circuits while maintaining detection capability.
Solution Approach 2:
The system performs self-diagnosis by utilizing its own existing signals for abnormality detection. The monitoring unit and determination unit use the CAN signal and SBW signal that already exist in the system to detect abnormalities in the signal line, without requiring external or additional specialized detection components.
2Reliability
If a new circuit is designed to receive the port input signal, then abnormality detection is enabled, but manufacturing cost increases
Solution Approach 1:
Existing signals are made multi-functional by using them both for their original purposes and for abnormality detection. The CAN signal and SBW signal are already present in the system, and the determination unit leverages these signals to detect abnormalities, eliminating the need for additional hardware and reducing manufacturing costs.
Solution Approach 2:
Instead of discarding existing signals after their primary function, the system recovers and reuses them for abnormality detection. The monitoring unit continuously monitors the CAN signal and SBW signal, and the determination unit analyzes their combinations to detect abnormalities, thereby recovering value from existing signals.
Data Source
AI summary
An abnormality detection device for detecting an abnormality of a signal line connecting an output of an ignition switch of a vehicle and a battery pack, the abnormality detection device comprising: a monitoring unit that monitors a first signal indicating a voltage of a signal line, a second signal indicating an ON/OFF state of an ignition switch communicated in a network of the vehicle, and a third signal indicating an ON/OFF state of an ignition switch output from a shift-by-wire system of the vehicle; and a determination unit that determines whether an abnormality is present in the signal line based on the first signal, the second signal, and the third signal monitored by the monitoring unit.