Hydrocarbon Adsorbent Coating for Low-Purge DBL Emission Control
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Solution Overview
Problem
Current hydrocarbon emission control systems, particularly in vehicles, face challenges with high diurnal breathing loss (DBL) emissions due to low purge volumes and infrequent purge cycles, leading to residual hydrocarbons being released into the atmosphere, and there is a need for systems that minimize air intake restriction and weight while reducing emissions effectively.
Innovation Solution
A coated substrate with a hydrocarbon adsorbent coating comprising particulate carbon and a binder, having a high BET surface area and n-butane adsorption capacity, is integrated into the air intake system and evaporative emission control canister to adsorb and desorb hydrocarbons efficiently, reducing DBL emissions and optimizing space and weight requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If carbon-containing honeycomb adsorbents are used to control evaporative emissions, then pressure drop is reduced, but diurnal breathing loss emissions increase due to residual hydrocarbons not being fully desorbed
Solution Approach 1:
The patent changes the physical-chemical parameters of the adsorbent material by specifying a BET surface area of at least 1400 m2/g and a second cycle n-butane adsorption capacity of at least 9% by weight. These parameter specifications ensure that the adsorbent can effectively capture hydrocarbons during adsorption while allowing for complete desorption during purge cycles, thereby reducing diurnal breathing loss emissions without sacrificing adsorption capacity.
Solution Approach 2:
The patent employs a composite adsorbent system comprising particulate carbon with high surface area characteristics combined with a binder to form a coated substrate. This composite structure integrates the adsorption capabilities of activated carbon with the structural integrity provided by the binder, creating a material that maintains both high adsorption capacity and effective desorption performance under varying operating conditions.
2Loss of energy
If purge volume is reduced in hybrid vehicles, then fuel economy improves, but diurnal breathing loss emissions increase due to lower total purge volume and higher residual hydrocarbon heel
Solution Approach 1:
The patent specifies critical parameters for the adsorbent material including a BET surface area of at least 1400 m2/g and a second cycle n-butane adsorption capacity of at least 9% by weight. These parameter specifications ensure that even with reduced purge volumes in hybrid vehicles, the adsorbent can achieve complete desorption of hydrocarbons, preventing residual hydrocarbon heel and associated diurnal breathing loss emissions while maintaining fuel economy benefits.
Solution Approach 2:
The high surface area adsorbent material inherently provides complete desorption during purge cycles without requiring additional purge volume. The material's physical-chemical properties enable it to self-regulate the desorption process, ensuring that all adsorbed hydrocarbons are released during the available purge window, thereby eliminating the need for increased purge volume to control emissions.
3Object-generated harmful factors
If adsorbent volume is increased to reduce diurnal breathing loss emissions, then emissions control improves, but weight and space requirements increase
Solution Approach 1:
The patent achieves superior emissions control with reduced adsorbent volume by changing the material parameters to include a BET surface area of at least 1400 m2/g and a second cycle n-butane adsorption capacity of at least 9% by weight. These enhanced parameters increase the adsorption efficiency per unit volume, allowing complete hydrocarbon capture and desorption in smaller adsorbent beds, thereby reducing both weight and space requirements while maintaining effective DBL emissions control.
Solution Approach 2:
The patent utilizes highly porous adsorbent material characterized by a BET surface area of at least 1400 m2/g. The porous structure provides extensive internal surface area within a compact volume, enabling high adsorption capacity and complete desorption in a small physical footprint. This porous material architecture allows the system to reduce adsorbent volume while maintaining effective emissions control performance.
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 solution effectively reduces diurnal breathing loss emissions to below 20 mg, maintains adsorption capacity under low purge conditions, and minimizes weight and space requirements, enhancing the overall efficiency of hydrocarbon emission control in vehicles.
Implementation Method 1
a hydrocarbon adsorbent coating comprising particulate carbon and a binder, having a high BET surface area and n-butane adsorption capacity, is integrated into the air intake system and evaporative emission control canister to adsorb and desorb hydrocarbons efficiently
Implementation Method 2
The particulate carbon has a BET surface area of at least about 1400 m2/g and a second cycle n-butane adsorption capacity of at least about 9% n-butane by weight
Implementation Method 3
the hydrocarbon adsorbent coating comprising particulate carbon and a binder
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, air intake systems, and evaporative emission control systems for controlling evaporative emissions of hydrocarbons from motor vehicle engines and fuel systems.