Fuel Cell Vehicle Insulation Fault Response by Fault Location
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Solution Overview
Problem
Fuel cell vehicles face safety risks due to insulation resistance value decreases between battery leads and chassis, causing electrical leakage, which existing systems address inadequately, leading to unsafe vehicle responses.
Innovation Solution
Implement a dual detection system using a fuel cell control unit and cell management system to differentiate insulation fault responses based on fuel cell startup state, employing distinct control strategies for insulation faults within and outside the fuel cell, including prompts, speed control, and high voltage power-down when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single insulation detection system is used for the entire vehicle, then the system complexity is low, but the safety response cannot be differentiated for faults inside vs. outside the fuel cell
Solution Approach 1:
The patent divides the insulation detection system into two separate detection paths: one for detecting insulation faults within the fuel cell and another for detecting insulation faults outside the fuel cell. This segmentation allows differentiated safety responses based on fault location, improving reliability without requiring a completely new system architecture.
Solution Approach 2:
The patent introduces an intermediary control unit that receives insulation resistance values from both detection systems and determines the appropriate safety response. This intermediary coordinates between the two detection systems and the execution units, enabling differentiated responses while maintaining system manageability.
2Reliability
If high voltage power-down is executed for any insulation fault, then occupant safety is maximized, but user experience deteriorates due to unnecessary power-downs for non-critical faults
Solution Approach 1:
The patent applies different safety response strategies based on the local nature of the fault. For insulation faults outside the fuel cell, a less severe response (speed limitation) is applied. For insulation faults inside the fuel cell, a more severe response (high voltage power-down) is applied. This local quality approach ensures safety while avoiding unnecessary disruptions.
Solution Approach 2:
The patent changes the response parameter (power-down vs. speed limitation) based on the detected insulation resistance value and fault location. By adjusting the severity of the response according to the specific conditions, the system maintains safety while improving user experience.
3Measurement precision
If insulation detection is performed continuously with high sensitivity, then fault detection accuracy is high, but false alarms increase leading to unnecessary safety responses
Solution Approach 1:
The patent implements dynamic threshold adjustment for insulation resistance detection. The system adapts the detection threshold based on operating conditions and historical data, allowing high sensitivity for fault detection while dynamically adjusting to avoid false alarms under normal operating variations.
Solution Approach 2:
The system incorporates feedback mechanisms where insulation resistance values are continuously monitored and compared against dynamic thresholds. The detection system learns from past operations and adjusts its sensitivity, maintaining high measurement precision while reducing false alarms through adaptive feedback control.
Data Source
AI summary
An insulation fault response method for a fuel cell vehicle, comprising: when a vehicle starts, detecting whether a fuel cell is in a startup state or not; when the fuel cell is not in the startup state, reading a first insulation resistance detected by a fuel cell control unit and a second insulation resistance detected by a cell management system; when the first insulation resistance indicates that the vehicle is in an insulation fault, executing a first control policy; and when the second insulation resistance indicates that the vehicle in an insulation fault, executing a second control policy, wherein the first control policy is different from the second control policy, and wherein when the first insulation resistance is less than a first threshold and/or the second insulation resistance is less than a second threshold, the vehicle is in an insulation fault.