Valve Device Sequential Seal Design for Fuel Evaporation Purge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In fuel evaporation gas purge systems, the detachment of the purge control valve from the intake passage during engine operation can lead to continuous operation of the purge pump, causing fuel vapor to be released into the atmosphere, resulting in external leakage and potential undetected abnormalities.
Innovation Solution
A valve device is attached to the intake passage of the engine, featuring a valve element that switches between permitting and blocking the inflow of evaporative fuel, with a design that includes an outflow port and a leak port, where the outflow seal breaks before the leak seal, ensuring that evaporative fuel flows into the intake passage without external leakage, even when the valve device is detached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the outflow seal is positioned to break before the leak seal when the valve device detaches, then external gas leakage is reduced, but the sealing reliability deteriorates
Solution Approach 1:
The sealing system is divided into two independent seals: an outflow seal for the outflow port and a leak seal for the leak port. This segmentation ensures that failure of one seal (outflow seal breaking first upon detachment) does not compromise the other seal (leak seal maintaining integrity), thereby preventing external gas leakage while managing the sequential failure mode
Solution Approach 2:
The outflow seal is deliberately positioned to break before the leak seal in the event of valve device detachment. This predetermined failure sequence acts as a protective measure where the outflow seal's earlier breakage prevents pressure buildup that could force the leak seal to fail, thus cushioning the system against complete sealing failure and external leakage
2Ease of repair
If the valve device is detached from the intake passage, then the valve element can be removed for maintenance, but fuel vapor is released into the atmosphere causing harmful emissions
Solution Approach 1:
The leak port and leak seal are extracted as a separate functional element from the main outflow path. The leak port provides a dedicated bypass channel that remains active even when the outflow seal fails or the valve is detached, ensuring fuel vapor can still be directed to the intake passage through the leak port rather than being released to the atmosphere
Solution Approach 2:
The leak seal acts as an intermediary sealing element that maintains the integrity of the leak port pathway. Even when the outflow seal fails during detachment or maintenance operations, the leak seal mediates by preserving the sealed connection at the leak port, allowing fuel vapor to flow through the leak passage into the intake passage without atmospheric release
Data Source
AI summary
A valve device includes an outflow port inserted in an engine port provided on an intake pipe so as to communicate with an intake passage. A leak port is inserted in the engine port and includes a leak passage into which evaporative fuel is allowed to flow regardless of a permitting state and a blocking state. A seal provides a sealed state between the outflow port and the engine port. Another seal provides a sealed state between the leak port and the engine port. The seal is positioned such that the sealed state of the seal becomes broken before breakage of the other seal when the outflow port and the leak port move in a direction away from the engine port.