Graphene EVAP Canister Adsorbent for Fuel Vapor Bleed Control
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Solution Overview
Problem
Conventional activated carbon adsorbent materials in EVAP canisters suffer from reduced adsorption capacity over time, leading to persistent 'bleed' issues, allowing trace amounts of harmful gasoline components to escape into the atmosphere during refueling or diurnal emissions.
Innovation Solution
Employing a graphene-based adsorbent material, including derivatives such as graphene oxide or functionalized graphene, incorporated into polymers like polyurethane or polypropylene, to enhance the adsorption and desorption of vaporized hydrocarbons in EVAP canisters, with varying loading concentrations and forms like pellets, foam, or felt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional activated carbon adsorbent material is used in EVAP canister, then the canister can store fuel vapors, but the adsorption capacity reduces over time causing persistent bleed issues and harmful emissions
Solution Approach 1:
The patent changes the fundamental material parameter from conventional activated carbon to graphene-based adsorbent material. This parameter change provides superior adsorption capacity, higher surface area, and improved structural stability that prevents the capacity reduction and bleed issues experienced with traditional activated carbon, thereby maintaining reliable vapor storage while reducing harmful emissions
Solution Approach 2:
The patent employs composite material construction by combining graphene-based adsorbent material with binder materials to form a structured adsorbent composition. This composite approach integrates the high-performance graphene component with supporting matrix materials, achieving both superior adsorption performance and structural integrity that conventional activated carbon cannot provide
2Object-generated harmful factors
If larger volume of adsorbent material is used to prevent emissions, then evaporative emissions are reduced, but the canister size and system complexity increases
Solution Approach 1:
By changing the adsorbent material parameter to graphene-based material with superior adsorption capacity and higher surface area, the patent achieves the same or better emission reduction performance with a smaller canister volume. The enhanced material properties allow for reduced material quantity while maintaining effective vapor storage capability
Solution Approach 2:
The patent utilizes the exceptional surface area-to-volume ratio of graphene structure to achieve high adsorption capacity in a compact form. The two-dimensional planar structure of graphene provides extensive surface area for vapor adsorption without requiring large volumetric space, enabling effective emission control in a compact canister
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 graphene-based adsorbent material maintains high adsorption capacity, effectively reducing evaporative emissions by adsorbing and desorbing fuel vapors efficiently, thereby meeting stringent EPA/CARB emission standards.
Implementation Method 1
a graphene based adsorbent material utilized in an EVAP canister... which can include any of activated-graphene derivatives or graphene-based foam compositions... adsorbing and storing fuel vapors
Implementation Method 2
the purge valve opens and allows the vacuum of the engine intake to siphon the fuel vapors from the carbon into the engine intake manifold (desorption)
Data Source
AI summary
An evaporative emissions control system for an automobile for reducing evaporative emissions, having an evaporative canister coupled to a fuel tank, the canister containing sorbent material capable of adsorbing hydrocarbons and selected from the group of activated Graphene-derivatives not limited to any of monolayer Graphene, few layered Graphene, Graphene oxide, reduced Graphene oxide, and functionalized Graphene. A vapor inlet on the canister is connected to the fuel tank, a purge outlet on the canister being connected to an air induction system, wherein the sorbent material adsorbs fuel vapors when the engine is not running and desorbs fuel vapors when the engine is running.