Fuel Cap Pressure Regulating Valve Flow Path Design
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Solution Overview
Problem
The existing fuel cap pressure regulating valves suffer from reduced quick pressure regulation performance due to the restriction member affecting the flow rate of the positive pressure valve, leading to increased passage resistance and decreased response efficiency.
Innovation Solution
The fuel cap incorporates a pressure regulating valve with a positive pressure valve and a negative pressure valve, where the positive pressure valve plug is equipped with a first spring and a restriction member that widens the passage area when the negative pressure valve opens, enhancing the flow rate and reducing passage resistance, while the negative pressure valve plug has a second spring and a cup-shaped design to improve differential pressure and valve-opening characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a restriction member is added to the negative pressure valve plug to increase differential pressure and improve negative valve flow rate, then the negative pressure valve performance is improved, but the positive pressure valve flow rate is reduced and quick pressure regulation performance deteriorates
Solution Approach 1:
The restriction member is positioned to selectively affect only the negative pressure valve flow path, creating localized flow characteristics that improve negative valve performance without impacting the positive pressure valve's quick response capability. The restriction is applied specifically where needed in the negative valve passage while leaving the positive valve passage unrestricted.
2Productivity
If passage resistance of the pressure regulating valve is reduced to enhance response, then quick pressure regulation performance is improved, but the number of required parts increases leading to higher cost
Solution Approach 1:
The positive and negative pressure valves are integrated into a single pressure regulating valve assembly with a unified valve body and shared structural components. The restriction member is incorporated as an integral part of the valve plug rather than a separate component, reducing the total part count while maintaining low passage resistance for quick response performance.
3Reliability
If the passage area of the first valve flow path is narrowed by the restriction member in closed position, then negative pressure valve flow characteristics are improved, but positive pressure valve flow rate is reduced
Solution Approach 1:
The valve plug design allows the restriction member to dynamically change its position relative to the first valve flow path based on valve operation mode. In negative pressure valve operation, the restriction member is positioned to narrow the passage and improve flow characteristics. In positive pressure valve operation, the valve plug moves to a position where the restriction member no longer constricts the first valve flow path, allowing full flow rate for quick pressure regulation.
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 design improves the quick pressure regulation performance of the positive pressure valve, reduces passage resistance, and decreases the number of required parts, resulting in enhanced response efficiency and cost reduction.
Implementation Method 1
a first spring that has one end fixed to the cap main body and applies a pressing force in a closing direction to the positive pressure valve plug
Implementation Method 2
a second spring that has one end fixed to the cap main body and applies a pressing force in a closing direction to the negative pressure valve plug
Implementation Method 3
a restriction member that is located to face the first valve flow path and narrows an passage area of the first valve flow path in a closed position of the negative pressure valve plug, thereby increasing a differential pressure applied to the negative pressure valve plug
Implementation Method 4
widening the passage area of the first valve flow path in an open position of the positive pressure valve plug where the negative pressure valve plug moves integrally with the positive pressure valve plug
Data Source
AI summary
A fuel cap of the invention has a pressure regulating valve, which includes a positive pressure valve and a negative pressure valve. The positive pressure valve has a positive pressure valve plug and a first spring. The negative pressure valve has a negative pressure valve plug and a second spring. A ring-shaped projection is protruded outward from the upper circumferential end of the negative pressure valve plug to face a first valve flow path, and functions as a restriction member. The restriction member narrows the passage area of the first valve flow path in a closed position of the negative pressure valve plug, while widening the passage area of the first valve flow path in an open position of the positive pressure valve plug where the negative pressure valve plug moves integrally with the positive pressure valve plug. This arrangement effectively improves the flow characteristics of the pressure regulating valve in the open position of the positive pressure valve.