Fuel Vapor Separator Baffle Design for Droplet Separation
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Solution Overview
Problem
Existing fuel systems face challenges in preventing fuel droplets from reaching the fuel vapor filter, which can damage its operation, and existing solutions like liquid vapor separators and expansion tanks have limitations in effectively separating and redirecting droplets back to the fuel tank.
Innovation Solution
A liquid vapor separator is designed with a body having an inlet connected to the fuel tank, an outlet connected to the fuel vapor filter, and a draining port that redirects fuel droplets back to the filler head, utilizing pressure differentials and a maze-like flow path to separate vapor from droplets, ensuring vapor reaches the filter while droplets are returned to the tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid vapor separator is used to prevent fuel droplets from reaching the fuel vapor filter, then the reliability of the fuel vapor filter is improved, but the device complexity increases due to the additional separating chamber and baffle structure
Solution Approach 1:
The liquid vapor separator is integrated within the existing fuel filler neck assembly, nesting the separation function inside the refueling infrastructure. The separating chamber and baffle are positioned within the filler neck's internal volume, utilizing existing space rather than adding external components.
Solution Approach 2:
The baffle acts as an intermediary element between the vapor inlet and the fuel vapor filter. It intercepts fuel droplets from the vapor flow and redirects them through the draining port back to the fuel tank, preventing droplets from reaching the filter while allowing vapor to pass through.
2Reliability
If an expansion tank is used to separate fuel vapor from droplets, then the separation efficiency is improved, but the volume of the device increases
Solution Approach 1:
The separator divides the filler neck internal volume into distinct functional zones: a vapor flow path that allows vapor to reach the filter, and a draining region that captures and redirects droplets. The baffle creates segmented flow paths that separate vapor and liquid phases spatially.
Solution Approach 2:
The baffle introduces a vertical dimension to the separation process by creating upward and downward flow paths. Vapor flows upward over the baffle toward the filter, while droplets are directed downward through the draining port, utilizing gravitational separation in the vertical dimension.
3Reliability
If a baffle is positioned to intercept fuel droplets from vapor flow, then the droplet removal efficiency is improved, but the pressure differential across the separator increases
Solution Approach 1:
Instead of blocking the vapor flow path with the baffle, the design inverts the approach by creating an open vapor path over the baffle while directing droplets away through a separate draining port. The vapor flow is maintained unobstructed, while the droplet removal function is achieved through the draining region.
Solution Approach 2:
The droplet removal function is extracted from the main vapor flow path and placed into a separate draining region. The baffle intercepts droplets and channels them into the draining port, separating the droplet removal function from the vapor transmission function to minimize pressure differential impact on vapor flow.
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 solution effectively prevents fuel droplets from reaching the fuel vapor filter, allowing vapor to be treated while droplets are redirected back to the fuel tank, enhancing the separation efficiency and reducing the risk of filter damage during refueling and normal operation.
Implementation Method 1
pressure differential between over the liquid vapor separator results in separation of the liquid fuel droplets from the fuel vapor such that liquid fuel can return by force of gravity towards the fuel tank
Implementation Method 2
liquid fuel can return by force of gravity towards the fuel tank
Implementation Method 3
some of the fuel vapor entering thereto may condense into droplets
Data Source
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AI summary
A liquid vapor separator for a vehicle's fuel system, said liquid vapor separator comprising a body having an inlet connectable with a venting system of a fuel tank and a vapor outlet connectable to a fuel vapor treating device, and a condensation space for condensation of fuel droplets, said space being in flow communication with said inlet and with said outlet, and said condensation space extending at or being in flow communication with a filler neck of the fuel system.