Fuel Tank Pressure Transducer Diagnosis via Hydrocarbon Sensor Feedback
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Solution Overview
Problem
The existing methods for diagnosing a pressure sensor in fuel systems are limited, leading to premature replacement and increased service costs, as they often rely on inaccurate diagnostic feedback due to canister degradation and restriction issues in evaporative emissions systems.
Innovation Solution
A method involving the use of a hydrocarbon sensor to diagnose the condition of a fuel tank pressure transducer (FTPT) by bypassing gases around saturated canisters, comparing the hydrocarbon sensor output to a threshold value, and determining if the FTPT is degraded based on a positive pressure reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure sensor is replaced in response to a diagnostic fault code, then the diagnostic accuracy is improved, but the service cost increases
Solution Approach 1:
The system uses the hydrocarbon sensor to provide feedback about actual vapor presence in the fuel tank, which is then used to validate or refute the pressure sensor's diagnostic readings. This feedback loop enables more accurate diagnosis by cross-checking pressure readings against actual hydrocarbon sensor responses, reducing false positives that would otherwise lead to unnecessary sensor replacement
Solution Approach 2:
The hydrocarbon sensor acts as an intermediary element that provides additional diagnostic information about the fuel vapor condition. By measuring hydrocarbon levels directly, it serves as a mediator to verify whether pressure sensor readings are accurate, thereby improving diagnostic reliability without requiring immediate sensor replacement
2Reliability
If the pressure sensor is replaced in response to a diagnostic fault code, then the reliability of the diagnostic system is improved, but unnecessary replacement increases
Solution Approach 1:
The hydrocarbon sensor provides feedback on actual vapor presence to validate pressure sensor readings, improving diagnostic reliability by cross-checking measurements and reducing false fault codes that would trigger unnecessary sensor replacement
Solution Approach 2:
The system uses existing sensor data from the hydrocarbon sensor to self-diagnose pressure sensor issues, eliminating the need for external diagnostic equipment or immediate sensor replacement while improving diagnostic reliability through internal cross-validation
3Object-affected harmful factors
If canisters are used in series to meet stricter evaporative emissions standards, then the emissions control effectiveness is improved, but the fluid flow restriction increases
Solution Approach 1:
The system segments the vapor flow path by providing alternative routes through canister bypasses, allowing vapor to flow around saturated canisters when necessary. This segmentation enables the canisters to remain in series for emissions control while providing relief paths that prevent excessive flow restriction during refueling operations
Solution Approach 2:
The canister bypass valves act as intermediaries that regulate vapor flow between the fuel tank and canisters. By controlling when vapor flows through canisters versus when it bypasses them, these valves mediate between the need for emissions control and the need to maintain adequate flow rates during refueling
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces unnecessary replacement of the FTPT, decreases manufacturing costs, and improves diagnostic accuracy by utilizing existing hardware in the evaporative emissions system.
Implementation Method 1
flowing gases directly to a hydrocarbon sensor via a canister bypass and diagnosing a condition of a fuel tank pressure transducer (FTPT) based on a response of the hydrocarbon sensor
Implementation Method 2
vaporized hydrocarbons (HCs) from a fuel tank may be stored in a fuel vapor canister packed with an adsorbent which adsorbs and stores the vapors
Data Source
AI summary
Methods and systems are provided for a diagnostic of a pressure sensor. In one example, a method includes bypassing one or more vapor canisters and determining a condition of the pressure sensor based on feedback from a hydrocarbon sensor.