Fuel Vapor Processing Apparatus with Segmented Adsorption Chambers
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Solution Overview
Problem
Existing fuel vapor processing apparatuses face challenges in preventing fuel vapor from diffusing to the atmosphere, particularly due to the heat of external air causing desorption and leakage through gaps between adsorbent granules with large void ratios, leading to potential pressure losses and inefficient vapor retention.
Innovation Solution
The apparatus is designed with a series of adsorption chambers, including a main chamber, a low filling-ratio chamber, and an atmosphere-side chamber, where the low filling-ratio chamber has a larger length-to-diameter ratio and a lower adsorbent filling ratio, and the atmosphere-side chamber has a higher pore volume per unit mass and smaller average pore diameter, inhibiting vapor diffusion and pressure loss while ensuring efficient adsorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If adsorbent granules with large diameter are used to prohibit increase in resistance against gas flow, then gas flow resistance is reduced, but fuel vapor leaks through gaps between granules to the outside
Solution Approach 1:
The adsorption chamber is divided into multiple chambers arranged in series, with each chamber containing adsorbent granules of different diameters. The first chamber uses large-diameter granules to minimize flow resistance, while subsequent chambers use progressively smaller granules to block vapor escape paths, collectively resolving the contradiction between gas flow resistance and vapor leakage prevention.
Solution Approach 2:
Different regions of the adsorption chamber are assigned different adsorbent granule sizes according to their functional requirements. The upstream region (first chamber) uses large granules for low resistance, while downstream regions (second and third chambers) use smaller granules for vapor blocking, creating a gradient structure that optimizes both flow and retention locally.
2Ease of operation
If adsorbent granules with large void ratio are used, then gas flow resistance is reduced, but fuel vapor desorbed due to external heat flows through gaps to leak outside
Solution Approach 1:
The single adsorption chamber is segmented into multiple chambers with progressively smaller granule sizes. This segmentation allows the system to maintain high void ratio in the first chamber for smooth gas flow while using smaller granules in subsequent chambers to eliminate escape gaps, thereby maintaining both flow ease and vapor retention reliability.
Solution Approach 2:
The adsorption system uses a composite structure of multiple adsorbent materials with different granule sizes arranged in series. This composite approach combines the advantages of large granules (low resistance, smooth flow) with the advantages of small granules (tight blocking, high retention), achieving both ease of operation and reliability simultaneously.
3Reliability
If filling ratio of adsorbent is increased to improve vapor adsorption, then vapor retention is improved, but resistance against gas flow increases
Solution Approach 1:
The adsorption chamber is segmented into multiple chambers, each with optimized filling ratios. The first chamber has lower filling ratio with large granules to minimize flow resistance, while subsequent chambers have progressively higher filling ratios with smaller granules to enhance vapor retention, collectively achieving both low resistance and high retention.
Solution Approach 2:
Different filling ratios are applied locally in different chambers based on functional requirements. The upstream chamber uses lower filling ratio for flow efficiency, while downstream chambers use higher filling ratios for vapor blocking, creating a spatial gradient that balances resistance and retention optimally.
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 configuration effectively delays fuel vapor diffusion, prevents its discharge from the atmospheric port, and maintains smooth refueling operations by optimizing the adsorbent distribution and chamber geometry, ensuring sufficient vapor retention and minimizing pressure losses.
Implementation Method 1
a fuel vapor processing apparatus having three segmented adsorption chambers each containing an adsorbent
Implementation Method 2
fuel vapor desorbed from the adsorbent due to the heat of the external atmospheric air
Data Source
AI summary
A fuel vapor processing apparatus may include a first adsorption chamber, a second adsorption chamber and a third adsorption chamber that are arranged in series with respect to a flow of gas. A ratio of a length to a diameter of the second adsorption chamber may be larger than a ratio of a length to a diameter of the first adsorption chamber. A filling ratio of an adsorbent within the second adsorption chamber may be smaller than a filling ratio of an adsorbent within the first adsorption chamber.