Activated Carbon Coated Substrates for Low DBL Emissions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current evaporative emission control systems face challenges in achieving low diurnal breathing loss (DBL) emissions, particularly in vehicles with reduced purge volumes, such as hybrid vehicles, due to high residual hydrocarbon heel and bleed emissions, which are not effectively managed by existing activated carbon materials.
Innovation Solution
The development of coated substrates with specific pore-size distributions and surface areas, combined with a binder, to enhance hydrocarbon adsorption capacity and reduce heel build, utilizing particulate carbon with a BET surface area of at least 1300 m2/g, micropore and mesopore volumes greater than certain thresholds, and high butane affinity, integrated into systems with sequential adsorbent volumes for improved emission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional activated carbon materials are used in evaporative emission control systems, then the system can adsorb hydrocarbons, but the residual hydrocarbon heel and bleed emissions are high, especially in vehicles with reduced purge volumes
Solution Approach 1:
The patent changes the physical parameters of the adsorbent material by specifying a BET surface area of at least 1300 m2/g and specific pore volume distributions (micropore volume and mesopore volume thresholds). These parameter changes enable the activated carbon to achieve lower residual hydrocarbon heel and bleed emissions while maintaining effective adsorption capacity for hydrocarbon control
Solution Approach 2:
The patent creates a composite structure by coating particulate carbon with specific pore-size distributions and surface areas onto a substrate, combining the adsorption properties of activated carbon with the structural support of the substrate. This composite approach reduces heel build and improves emission control performance while maintaining space efficiency
2Duration of action of stationary object
If activated carbon undergoes many thousands of adsorption/desorption cycles, then the system can continuously control evaporative emissions, but irreversible adsorption accumulates, decreasing the overall effective adsorption capacity
Solution Approach 1:
The patent modifies the adsorbent material parameters by specifying a BET surface area of at least 1300 m2/g and controlled pore volume distributions. These parameter changes reduce irreversible adsorption accumulation over time, allowing the activated carbon to maintain higher effective adsorption capacity throughout its service life during repeated adsorption/desorption cycles
3Object-generated harmful factors
If stricter regulations for permissible hydrocarbon emissions are implemented, then emission control performance is improved, but the complexity of the control system increases
Solution Approach 1:
The patent achieves compliance with stricter emission regulations by changing the physical parameters of the adsorbent material (BET surface area of at least 1300 m2/g, specific pore volume distributions). This material parameter change enables the system to meet low emission standards without adding complex control mechanisms, thereby reducing overall system complexity while improving emission control performance
4Quantity of substance
If coated substrates with specific pore-size distributions and high surface areas are used, then hydrocarbon adsorption capacity is enhanced and heel build is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies target parameter ranges for the coated substrate manufacturing (BET surface area of at least 1300 m2/g, micropore volume and mesopore volume thresholds). By defining these parameter ranges, the patent enables enhanced hydrocarbon adsorption capacity and reduced heel build while providing clear manufacturing specifications that balance performance requirements with manufacturability
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 coated substrates achieve low DBL emissions even under low purge conditions, maintaining high adsorption capacity and reducing heel build, thereby meeting stringent emission regulations and minimizing space and weight requirements.
Implementation Method 1
particulate carbon with a BET surface area of at least 1300 m2/g, and at least one of: (i) a butane affinity of greater than 60% at 5% butane; (ii) a butane affinity of greater than 35% at 0.5% butane; (iii) a micropore volume greater than about 0.2 ml/g and a mesopore volume greater than about 0.5 ml/g
Data Source
AI summary
The present disclosure relates to hydrocarbon emission control systems. More specifically, the present disclosure relates to substrates coated with hydrocarbon adsorptive coating compositions and evaporative emission control systems for controlling evaporative emissions of hydrocarbons from motor vehicle engines and fuel systems.