Double Check Valve for Fuel System Pressure Management
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Solution Overview
Problem
Existing fuel system valves in vehicles face challenges with pressure fluctuations due to fuel expansion in hot climates leading to potential leakage or engine malfunction, and low temperatures causing tank deformation or cracking, necessitating a valve that manages high flow rates and venting while minimizing parts and failure modes.
Innovation Solution
A two-way valve with a single displaceable plunger and coaxial flow paths, featuring a major and minor check valve, where the major valve allows high flow in the upstream direction and the minor valve allows flow in the downstream direction under vacuum conditions, using a resilient sealing sleeve and spring biasing for pressure threshold control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fuel system uses multiple separate valves for pressure relief and check functions, then reliability is improved through redundancy, but device complexity increases and failure modes multiply
Solution Approach 1:
The patent combines a check valve and a pressure relief valve into a single integrated valve assembly. The check valve portion includes a check valve body with a check valve seat and a movable check valve element, while the pressure relief valve portion includes a relief valve seat and a movable relief valve element, both within one valve body. This merging reduces the number of separate components and potential failure points while maintaining the reliability benefits of having both check and pressure relief functions.
Solution Approach 2:
The single valve assembly performs multiple functions: it acts as a check valve to prevent backflow of fuel from the feed line to the tank, and simultaneously functions as a pressure relief valve to relieve excessive pressure in the fuel tank. The valve body houses both valve mechanisms that operate independently but are integrated into one component, providing multi-functionality that reduces overall system complexity.
2Productivity
If a fuel system allows high flow rates from tank to engine, then fuel supply efficiency is improved, but pressure fluctuations increase causing potential leakage or engine malfunction
Solution Approach 1:
The pressure relief valve portion provides feedback control by monitoring pressure conditions in the fuel tank and automatically relieving excess pressure when it exceeds predetermined thresholds. The relief valve element moves in response to pressure changes, opening the relief passage to reduce pressure and closing when pressure normalizes, thereby stabilizing the fuel system during high flow rate operation.
3Reliability
If a fuel system provides venting capability to prevent vacuum in the fuel tank, then tank integrity is protected, but additional valve components increase device complexity
Solution Approach 1:
The venting function is integrated into the same valve assembly that provides check and pressure relief functions. The pressure relief valve portion includes a relief passage and relief valve element that can open to vent pressure or vacuum conditions from the fuel tank to the atmosphere or to the engine side, protecting tank integrity without requiring a separate vent valve component.
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
The valve ensures efficient fuel supply and venting, reducing the risk of leakage and engine malfunction by allowing high flow rates in the upstream direction while preventing reverse flow, thus maintaining system integrity and simplifying assembly with fewer components.
Implementation Method 1
a spring biasing the plunger into sealing engagement with the housing formed at the major flow path
Implementation Method 2
fitted with a deformable resilient sealing sleeve or cover layer normally sealing said apertures
Data Source
AI summary
Disclosed is a valve having a housing formed with a downstream port and an upstream port, with an axially displaceable plunger biased into sealing engagement of a major flow path extending between the downstream port and the upstream port for admitting flow only in the upstream direction, with the plunger formed having a normally closed minor flow path for admitting flow only in a downstream direction.