On-Board Diagnostic Mode Switching for Cold Startup
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Solution Overview
Problem
The on-board diagnostic system in motor vehicles often inaccurately indicates malfunctions, particularly when starting in cold temperatures or using alternative fuels like ethanol, leading to excessive activation of the malfunction indicator light, causing operator confusion and frustration.
Innovation Solution
Implementing a system that determines a feedback correction factor and engine oil temperature to switch between judging and non-judging modes, where the system ignores or evaluates diagnostic items based on these conditions, preventing false alarms during startup with ethanol fuel and ensuring reliable diagnostics when conditions are suitable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the on-board diagnostic system continuously monitors and judges diagnostic items, then the reliability of emission monitoring is improved, but false alarms occur during cold startup with ethanol fuel
Solution Approach 1:
The diagnostic system dynamically adjusts its monitoring mode based on operating conditions. The control unit switches between a first mode (continuous judging) and a second mode (suspended judging) depending on whether the vehicle is in cold startup conditions with ethanol fuel. This dynamic adaptation allows the system to maintain high reliability during normal operation while avoiding false alarms during cold startup with alternative fuels.
Solution Approach 2:
The system changes the operational parameters of the diagnostic monitoring based on detected conditions. When cold startup with ethanol fuel is detected, the system changes from a state of active judgment to a state of suspended judgment for specific diagnostic items. This parameter change allows the system to adapt its behavior to different operating conditions, preventing false alarms while maintaining monitoring capability when appropriate.
2Object-affected harmful factors
If the system enters non-judging mode to ignore diagnostic items, then false alarms are reduced, but diagnostic accuracy during unreliable conditions worsens
Solution Approach 1:
The system dynamically switches between monitoring modes based on operating conditions. During cold startup with ethanol fuel, the system enters a second mode where judgment of certain diagnostic items is suspended, preventing false alarms. When normal operating conditions are detected, the system transitions to a first mode where continuous monitoring and judgment resume, ensuring diagnostic accuracy when measurements are reliable.
Solution Approach 2:
The system extracts or suspends the judgment function for specific diagnostic items under specific conditions. Rather than completely disabling monitoring, the system selectively suspends judgment only for diagnostic items that would be unreliable during cold startup with ethanol fuel, while maintaining monitoring capability for other parameters. This selective extraction preserves diagnostic accuracy for reliable parameters while avoiding false alarms from unreliable ones.
Data Source
AI summary
Embodiments provide systems and methods for using a feedback correction factor to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system. If the feedback correction factor is within a predetermined range, the vehicle is placed in a judging mode. If the feedback correction factor is outside a predetermined range, the vehicle is placed in a non-judging mode. Methods and systems for using an engine oil temperature to determine whether a motor vehicle should be placed in a judging or non-judging mode regarding the on-board diagnostic system are disclosed. If an engine oil temperature, or predicted engine oil temperature, is below a predetermined temperature, the motor vehicle is placed in a non-judging mode. If an engine oil temperature, or predicted engine oil temperature, is above a predetermined temperature, the motor vehicle is placed in a judging mode.