Multilayer Micro Capsule Canister for Fuel Vapor Adsorption
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Solution Overview
Problem
The existing fuel vapor treatment canisters for internal combustion engines face issues with temperature fluctuations due to adsorption and desorption reactions, leading to deteriorated performance, and the leakage of phase-change materials from micro capsules can clog activated carbon, impairing adsorption ability and potentially affecting engine combustion stability.
Innovation Solution
A canister design incorporating a granular heat storing material with micro capsules having a multilayer outer shell, comprising a hydrophobic inner layer and a hydrophilic outer layer, to prevent permeation and maintain effective heat storage and adsorption, while ensuring the micro capsules remain stable within the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-layer hydrophobic resin is used for the micro capsule outer shell, then mechanical strength is improved, but permeation resistance to organic compounds is insufficient
Solution Approach 1:
The patent applies composite materials by combining a hydrophobic resin (such as polyethylene or polypropylene) with a hydrophilic resin (such as gelatin or carrageenan) to form a multilayer outer shell. The hydrophobic layer provides mechanical strength and water resistance, while the hydrophilic layer provides permeation resistance to organic compounds through its affinity for organic substances. This composite structure resolves the contradiction by achieving both high mechanical strength and effective permeation resistance simultaneously.
2Reliability
If the micro capsule outer shell is made highly resistant to organic compound permeation, then phase-change material leakage is prevented, but manufacturing complexity increases
Solution Approach 1:
The patent employs thin film technology by forming the multilayer outer shell as a thin composite membrane. The hydrophobic resin layer and hydrophilic resin layer are each formed as thin coatings, typically with total thickness in the micrometer range. This thin film approach achieves high permeation resistance with minimal material usage and maintains manufacturing simplicity through established coating and encapsulation techniques, avoiding the need for complex multi-step assembly processes.
3Object-affected harmful factors
If ethanol-blended gasoline is used to reduce environmental impact, then emissions are reduced, but micro capsule permeation increases due to blending effects
Solution Approach 1:
The hydrophilic resin layer acts as an intermediary barrier between the ethanol-blended gasoline and the phase-change material. The hydrophilic resin (such as gelatin or carrageenan) has specific affinity for organic compounds including ethanol, creating a selective barrier that interacts with the blended fuel components. This intermediary layer prevents direct contact between the ethanol-gasoline mixture and the micro capsule contents, maintaining permeation resistance even when exposed to blended fuels, thereby allowing the use of environmentally friendly ethanol-blended gasoline without compromising capsule integrity.
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 effectively stabilizes temperature changes, enhances adsorption performance, and prevents micro capsule leakage, thereby improving the service life and operational reliability of the canister, even with blended fuels like ethanol-blended gasoline.
Implementation Method 1
micro capsules each including a phase-change material enclosed in a multilayer outer shell... capable of absorbing latent heat and releasing heat with phase change
Implementation Method 2
repeating melting and solidification in a canister
Implementation Method 3
an inner layer of a hydrophobic resin and an outer layer of a hydrophilic resin
Implementation Method 4
prevent permeation and maintain effective heat storage and adsorption
Implementation Method 5
activated carbon capable of adsorbing organic compound... the organic compound is trapped by the activated carbon
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A canister includes a casing (10) having a gas passage (C) which extends from a first passage end formed with a charge port (11) to let in fuel vapor and a purge port (12) to let out the fuel vapor, to a second passage end formed with an atmospheric air port (13) to let in air, and which includes a heat storing and adsorbing chamber (C1,C2) in which a granular adsorbing material (7,7') and a granular heat storing material (6) are held. The granular heat storing material (6) contains capsules (5) each including a phase-change material enclosed in a multilayer outer shell which includes an inner layer (2) of a hydrophobic resin and an outer layer (3) of a hydrophilic resin covering the inner layer.