Sorbent Unit for Cold-Start Emission Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust treatment systems for vehicle engines face inefficiencies in reducing gaseous pollutants like NOx and hydrocarbons during the cold start phase due to low conversion efficiency of catalysts at low temperatures, leading to residual pollutants in exhaust emissions.
Innovation Solution
An exhaust treatment system incorporating a three-way catalyst, a particulate filter, and a sorbent unit with multiple sorbents, including activated carbon and zeolites, which adsorbs pollutants downstream of the catalyst and filter, maximizing adsorption efficiency by utilizing distinct sorbent layers to handle different types of molecules and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a three-way catalyst is used to treat gaseous pollutants, then conversion efficiency is improved at operating temperature, but conversion efficiency deteriorates during cold start phase
Solution Approach 1:
A sorbent unit comprising activated carbon and zeolite is introduced as an intermediary component between the three-way catalyst and tailpipe. This sorbent unit captures gaseous pollutants (HC, CO, NOx) that pass through the catalyst during cold start when the catalyst is not yet active, thereby mediating the gap between catalyst activation and emission control requirements
Solution Approach 2:
The sorbent unit performs preliminary adsorption of gaseous pollutants before they are released to the atmosphere. By positioning the sorbent unit downstream of the catalyst, it pre-captures pollutants during the cold start phase when the catalyst cannot yet convert them effectively, ensuring emissions are controlled from the outset
2Device complexity
If a single sorbent material is used in the sorbent unit, then device complexity is reduced, but adsorption efficiency for different pollutant types deteriorates
Solution Approach 1:
The sorbent unit employs a composite structure combining two different sorbent materials: activated carbon and zeolite. Activated carbon effectively adsorbs hydrocarbons (HC) and carbon monoxide (CO), while zeolite selectively captures nitrogen oxides (NOx). This composite approach leverages the complementary adsorption properties of different materials to achieve comprehensive pollutant removal
Solution Approach 2:
Different regions of the sorbent unit are assigned different sorbent materials optimized for specific pollutant types. The activated carbon layer targets HC and CO, while the zeolite layer targets NOx, creating localized functional zones that maximize overall adsorption efficiency for diverse gaseous pollutants
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 system effectively reduces the release of gaseous pollutants from the tailpipe during engine cold-starts by enhancing pollutant conversion and storage capacity, improving air quality and compliance with emission regulations.
Implementation Method 1
a sorbent unit comprising a first sorbent and a second sorbent downstream of the three-way catalyst and the particulate filter on the exhaust line
Data Source
AI summary
An exhaust treatment system includes an engine, an exhaust line in fluid communication with the engine, a three-way catalyst downstream of the engine on the exhaust line, a particulate filter downstream of and proximate to the three-way catalyst on the exhaust line, and a sorbent unit comprising a first sorbent and a second sorbent downstream of the three-way catalyst and the particulate filter on the exhaust line. The first sorbent and the second sorbent are proximate to a tailpipe of the exhaust line. A method of treating an exhaust emission from an internal combustion engine during an engine cold-start is also described.