Canister Thermal Storage Microcapsule for Fuel Vapor Adsorption
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Solution Overview
Problem
Existing canisters for evaporated fuel treatment in internal combustion engines face challenges in effectively managing temperature changes during fuel adsorption and purging, leading to increased weight due to the use of thermal storage particles and potential interference with gasoline vapor due to thin resin films in thermal storage material microcapsules.
Innovation Solution
Incorporating a thermal storage material that utilizes latent heat, such as a phase change substance or microcapsule, into the canister in a way that it is not directly contacted by gasoline vapor, and using a sealed container with enhanced thermal conductivity to manage temperature changes efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal storage particles with large specific heat and large gravity are used to restrain temperature rise and drop during adsorption and purging, then the temperature control effect is improved, but the weight of the canister increases
Solution Approach 1:
The patent utilizes the phase transition (melting and solidification) of thermal storage material within microcapsules to absorb and release latent heat. During fuel adsorption, the material melts absorbing heat to prevent temperature rise; during purging, it solidifies releasing heat to prevent temperature drop. This phase transition mechanism provides effective temperature control with much lighter weight compared to conventional thermal storage particles.
Solution Approach 2:
The thermal storage material is encapsulated within microcapsule structures, creating a nested configuration where the thermal storage material is contained inside the microcapsule shell. This nesting approach protects the thermal storage material from direct contact with gasoline vapor while maintaining thermal contact with the adsorptive material, solving both the contamination and weight issues.
2Weight of stationary object
If thermal storage material microcapsule with thin resin film is used to reduce weight, then the weight of canister is reduced, but gasoline vapor may pass through the film and change melting point of thermal storage material
Solution Approach 1:
The patent employs thin resin film microcapsules to encapsulate the thermal storage material. These flexible thin films significantly reduce the overall weight of the canister while still providing adequate containment. The thin film design is optimized to balance permeability resistance with weight reduction, preventing gasoline vapor from reaching the thermal storage material.
Solution Approach 2:
The microcapsule shell acts as an intermediary barrier between the thermal storage material and gasoline vapor. This intermediate layer prevents direct contact and potential contamination while allowing thermal energy transfer to occur, thus protecting the thermal storage material's melting point from being altered by gasoline vapor.
3Use of energy by stationary object
If thermal storage material is directly contacted with gasoline vapor, then heat transfer efficiency is improved, but melting point of thermal storage material changes due to vapor interference
Solution Approach 1:
The microcapsule shell serves as an intermediary that enables indirect thermal contact between the thermal storage material and the surrounding environment including gasoline vapor. This intermediary structure maintains thermal coupling for efficient heat transfer while simultaneously preventing chemical contamination that would alter the melting point of the thermal storage material.
Solution Approach 2:
The thin resin film of the microcapsule provides sufficient thermal conductivity to maintain effective heat transfer while being thin enough to minimize thermal resistance. This thin film configuration ensures that the thermal storage material remains thermally coupled to the system without direct exposure to gasoline vapor that would change its melting point.
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 approach effectively restrains temperature rises and drops during adsorption and purging, improves adsorption and purging performance, and prevents interference with gasoline vapor, while reducing the canister's weight and cost.
Implementation Method 1
a thermal storage material made of a phase change substance which absorbs and discharges latent heat in response to a temperature change
Implementation Method 2
a phase change substance which absorbs and discharges latent heat in response to a temperature change
Implementation Method 3
an adsorptive material chamber which contains an adsorptive material adsorbing evaporated fuel
Data Source
AI summary
In a canister and a method of manufacturing a canister, in order to restrain a temperature rise of an adsorptive material owing to adsorption of an evaporated fuel (gasoline vapor) or to restrain a temperature drop of the adsorptive material during purging of the adsorbed gasoline vapor and to increase adsorbing and purging amounts, or in order to improve adsorbing and purging performances of the evaporated fuel, there is disposed a thermal storage material constituted of a phase change substance which absorbs and discharges latent heat in response to a temperature change or a thermal storage material microcapsule constituted by confining the thermal storage material in a microcapsule in a state in which the material or the microcapsule is not brought into direct contact with the evaporated fuel, and especially in the vicinity of the adsorptive material in a heat-conduction state, so that the temperature change is restrained by the thermal storage material in response to the temperature rise or drop of the adsorptive material to prevent deterioration of the adsorbing performance of an activated carbon due to the temperature rise and deterioration of the purging performance of the activated carbon due to the temperature drop.