Hybrid Vehicle Fuel Ventilation Device with Segmented Enclosures
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Solution Overview
Problem
The positioning of the fuel tank isolation valve (FTIV) in hybrid vehicle fuel systems either splits the fuel system into two zones, making it difficult to comply with on-board diagnosis (OBD) regulations or allows fuel vapor to be sucked in from the tank during purging, and existing solutions require expensive electronic controls or multiple valves.
Innovation Solution
A single ventilation device with two separate enclosures and shutter devices, one normally closed and one normally open, connected to the filler tube, tank, and atmosphere, along with a combined pressure/vacuum relief valve, allows for efficient tank ventilation during filling while preventing fuel vapor release, using mechanical activation to simplify and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the fuel tank isolation valve is positioned upstream from the canister to prevent vapor being sucked in during purging, then fuel vapor release is prevented, but the fuel system is split into two zones making it difficult to comply with OBD regulations
Solution Approach 1:
The ventilation device is divided into two separate enclosures (first enclosure for atmosphere connection, second enclosure for tank connection) with independent shutter devices. This segmentation allows each enclosure to perform its specific function independently while maintaining overall system integrity, enabling both vapor prevention and OBD compliance through separate control zones.
Solution Approach 2:
The first enclosure acts as an intermediary component between the canister and the atmosphere, providing a controlled interface that allows vapor prevention during purging while maintaining system connectivity for OBD testing. The intermediary structure enables signal transmission and system communication without direct vapor pathway creation.
2Adaptability or versatility
If the fuel tank isolation valve is positioned downstream from the canister to facilitate OBD testing, then OBD compliance is improved, but fuel vapor can be sucked in from the tank during purging
Solution Approach 1:
By segmenting the ventilation device into two independent enclosures with separate shutter devices, the system allows the second enclosure (tank connection) to remain open for OBD testing while the first enclosure (atmosphere connection) controls vapor release through its shutter mechanism, preventing vapor suction during purging.
Solution Approach 2:
Different parts of the ventilation device have different functional qualities: the first enclosure is designed with vapor prevention capability through its normally closed shutter, while the second enclosure is designed with tank connection capability for OBD testing. Each local region performs its specific function optimally without interfering with the other.
3Adaptability or versatility
If two separate valves are used to control ventilation during filling and disconnection during purging, then both functions are achieved, but the device complexity and cost increase
Solution Approach 1:
Two separate valve functions (ventilation control during filling and disconnection during purging) are merged into a single ventilation device with two enclosures. The first enclosure handles atmosphere ventilation control, while the second enclosure handles tank connection control, eliminating the need for separate valves and reducing overall system complexity.
Solution Approach 2:
The single ventilation device performs multiple functions: it controls atmosphere ventilation, manages tank connection/disconnection, prevents vapor release, and enables OBD testing. By making the device universal and multi-functional, the patent eliminates the need for multiple specialized components, reducing complexity while maintaining full functionality.
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 solution effectively regulates tank pressure and prevents fuel vapor from being sucked in during purging, simplifying the fuel system design, enhancing compliance with OBD regulations, and reducing costs by eliminating the need for electronic controls.
Implementation Method 1
a combined pressure/vacuum relief valve or an over-pressure relief and under-pressure relief valve pair situated in or fastened to a bypass of the first passage (1) so as to be able to establish a connection between the ends of said passage (1) when the shutter device (F) is closed and when there is over- or under-pressure from end to end of the passage
Data Source
AI summary
A ventilation device including: a first enclosure including a first passage configured to be connected to a canister outlet and the atmosphere, and a normally closed shutter device configured to open to release the first passage; a second enclosure including a second passage configured to be connected to the canister inlet and a fuel tank, and a normally open shutter device configured to close to shut the second passage, the second passage being separate from and not in communication with the first passage; and a combined pressure/vacuum relief valve or OPR and UPR valve pair situated in or fastened to a bypass of the first passage configured to establish a connection between ends of the first passage when the shutter device is closed and when there is over- or under-pressure in the ends. A fuel system can include the device and a hybrid vehicle can include the fuel system.