Capless Fuel System with Integrated Flapper and Pressure Relief Valves
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing capless fuel systems for automotive vehicles face issues such as increased size and cost due to the positioning of pressure relief valves, flapper valve sticking, air entrainment during fueling, and the risk of incorrectly filling gasoline tanks with diesel fuel, leading to potential engine damage.
Innovation Solution
A capless fuel system with axially aligned fluid ports and flapper valves, pressure relief valves integrated within the flapper valves, and diametrically opposed latches to prevent incorrect nozzle insertion, ensuring compact design, proper fueling, and preventing pressure buildup and air entrainment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure relief valves are positioned radially outwardly from the flapper valve in previously known capless systems, then the fuel tank pressure can be vented effectively, but the overall housing size increases and material cost increases
Solution Approach 1:
The patent combines the pressure relief valve and flapper valve into a single integrated valve assembly. The pressure relief valve is positioned within the housing at a location that allows it to function independently while sharing the same valve body structure as the flapper valve, eliminating the need for separate radial positioning and reducing overall housing volume.
Solution Approach 2:
The pressure relief valve is nested within the same housing space as the flapper valve, with both valves sharing common structural elements. The pressure relief valve is positioned to utilize the existing housing volume rather than requiring additional radial space, effectively nesting multiple functions within a compact configuration.
2Reliability
If the flapper valve is used to prevent fuel fume escape during normal operation, then fuel fume containment is improved, but the flapper valve may get stuck between the nozzle insert and nozzle during fuel filling
Solution Approach 1:
The patent introduces a nozzle insert as an intermediary component between the flapper valve and the fuel nozzle. This insert acts as a mediator that guides the nozzle during insertion and prevents direct contact between the nozzle and flapper valve, eliminating the sticking problem while maintaining fuel fume containment functionality.
Solution Approach 2:
The flapper valve is designed to automatically open and close based on the presence or absence of the fuel nozzle, without requiring manual intervention. The valve responds to the nozzle's insertion and removal through pressure differential changes, ensuring reliable operation while preventing sticking through its automatic response mechanism.
3Productivity
If air is entrained within the fuel flow from the nozzle into the fuel fill pipe, then fueling can proceed, but fuel fumes are created and entrapped within carbon canisters
Solution Approach 1:
The patent converts the potentially harmful effect of air entrainment into a beneficial filtering mechanism. The carbon canister, which would normally trap harmful fuel fumes, is positioned to receive and filter the air-fuel mixture during filling. The system accepts air entrainment as inevitable but uses the carbon canister to remove harmful components, transforming a harmful byproduct into a filtering opportunity.
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 system maintains a compact size, prevents fuel fume escape, ensures correct fuel type filling, and reduces air entrainment, thus enhancing operational efficiency and preventing engine damage.
Implementation Method 1
a flapper valve which is fluidly connected in series between the inlet and the outlet of the housing. A spring urges the flapper valve against a valve seat contained within the housing in order to prevent the escape of fuel fumes into the atmosphere
Implementation Method 2
a pressure relief valve formed in the housing. These pressure relief valves would open when the pressure within the fuel tank exceeded a predetermined pressure. Upon opening, the pressure relief valves would vent the fuel fumes
Implementation Method 3
A spring urges the flapper valve against a valve seat contained within the housing in order to prevent the escape of fuel fumes into the atmosphere
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A capless fuel system having an elongated tubular and cylindrical housing open at each end and in which the housing defines a first and a second longitudinally spaced fluid ports. A first flapper valve is associated with the first fluid port and a second flapper valve is associated with the second fluid port. A pair of diametrically opposed latches pivotally mounted to the housing adjacent the second fluid port retain the second flapper valve in a closed position until a fuel nozzle of a predetermined size is inserted towards the second port. The fuel nozzle engages camless surfaces which pivot the latches away from the second flapper valve allowing the fuel filling nozzle to pass through the second port.