Fuel Tank Overpressure Control After Purge Check Valve Failure
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Solution Overview
Problem
In turbo vehicles, when the check valve breaks down, compressed intake air can flow into the fuel tank, leading to excessive pressure and potential expansion, which existing systems fail to prevent effectively.
Innovation Solution
A fuel system with a controller that monitors pressure differences between the intake line and fuel tank to detect check valve failures, activating the purge control valve to close and prevent intake air from entering the fuel tank, and using recirculation and wastegate valves to manage pressure, entering a fail-safe mode to prevent tank expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a check valve is used to prevent intake air from flowing to the fuel tank, then the fuel tank is protected from overpressure, but the system becomes vulnerable when the check valve breaks down
Solution Approach 1:
The patent introduces a purge control valve as an intermediary component between the intake line and fuel tank system. This valve acts as a secondary mediator that can be actively controlled to prevent intake air from reaching the fuel tank when the check valve fails, thereby providing redundant protection without requiring complete system redesign
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors the operational status of the check valve and the pressure conditions in the fuel tank. When abnormal conditions are detected (indicating check valve failure), the controller automatically activates the purge control valve to close, preventing further air intake and protecting the fuel tank from overpressure
2Reliability
If the purge control valve is kept closed to prevent air intake when check valve fails, then fuel tank expansion is prevented, but the system requires continuous monitoring and active control
Solution Approach 1:
The system is designed to self-diagnose and self-correct when check valve failure occurs. The controller automatically detects the failure condition through pressure monitoring and autonomously activates the purge control valve without requiring external intervention, enabling the system to protect itself from fuel tank expansion
Solution Approach 2:
The patent replaces purely passive mechanical protection (check valve only) with an active control system that uses electronic sensors and controllers to monitor system status and dynamically adjust valve positions. This substitution of mechanical-only approach with electromechanical control enables more reliable failure detection and response
3Measurement precision
If pressure monitoring is used to detect check valve failure, then accurate detection is achieved, but the system requires additional sensors and control logic
Solution Approach 1:
The pressure sensors and controller are designed to serve multiple functions: they monitor not only check valve status but also overall fuel tank pressure conditions, intake line pressure, and system anomalies. This multi-functionality allows accurate check valve failure detection while maximizing the utility of each sensor and control component
Solution Approach 2:
The system detects check valve failure by monitoring changes in pressure parameters within the fuel tank and intake line. When the check valve fails, characteristic pressure changes occur that the controller detects and interprets as failure conditions, enabling accurate detection through parameter analysis rather than requiring dedicated failure sensors
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
Effectively prevents the introduction of intake air into the fuel tank, thereby preventing expansion and reducing the risk of safety-related accidents due to check valve failures.
Implementation Method 1
a compressor configured to selectively compress intake air supplied to the engine
Implementation Method 2
a canister configured to capture fuel vapor discharged from a fuel tank
Data Source
AI summary
A vehicle fuel system includes a turbocharger having a compressor disposed on an intake line of an engine. The compressor selectively compresses intake air supplied to the engine. The fuel system has a canister configured to capture fuel vapor discharged from a fuel tank and a purge control valve configured to open or close the purge line depending on a pressure of the intake line. The fuel system has a check valve provided on the purge line that blocks movement of a fluid from the intake line to the canister. The fuel system has a controller performing control such that the purge control valve is operated in a closed mode to prevent intake air in the intake line from being introduced into the fuel tank when breakdown of the check valve is sensed during driving of the vehicle.