Solid Oxide Fuel Cell for Diesel Exhaust Treatment
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Solution Overview
Problem
Current technologies face challenges in effectively reducing NOx and particulate matter emissions from diesel engines, with existing solutions either compromising engine efficiency or requiring additional treatment steps, and there is a need for environmentally friendly and reliable power generation systems for vehicles.
Innovation Solution
A power generation system that combines an internal combustion engine operating in low temperature combustion mode with external exhaust gas recirculation and an intermediate temperature solid oxide fuel cell to treat exhaust gases, reducing NOx and particulate matter emissions without additional treatment, and includes a reducing catalyst and oxidation catalyst for further emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the adiabatic flame temperature is limited to reduce NOx production, then NOx emissions are reduced, but engine efficiency decreases and smoke appears in the exhaust
Solution Approach 1:
A fuel cell is introduced as an intermediary component between the engine and the exhaust system. The fuel cell processes the exhaust gases, removing NOx and particulate matter while generating electrical power that can be used to improve overall system efficiency, thus resolving the trade-off between emission reduction and engine efficiency
Solution Approach 2:
The exhaust gases, which contain harmful pollutants like NOx and particulate matter, are converted into a useful resource by feeding them into the fuel cell. The fuel cell extracts energy from these harmful components, generating electricity while simultaneously cleaning the exhaust, thus transforming the harmful emissions into a beneficial power source
2Object-generated harmful factors
If lean-burn NOx catalysts are used to reduce NOx under oxygen-rich conditions, then NOx reduction is achieved, but the catalysts are hydrothermally unstable and lose activity quickly
Solution Approach 1:
The fuel cell acts as an intermediary that pre-processes the exhaust gases before they reach the catalyst. By removing oxygen and converting CO and hydrocarbons in the fuel cell, the exhaust composition is modified to create a more favorable environment for the catalyst, reducing oxidative stress and improving its durability
Solution Approach 2:
The fuel cell changes the chemical parameters of the exhaust gas by consuming oxygen, CO, and hydrocarbons through electrochemical reactions. This parameter change creates a reduced atmosphere that is less harsh on the catalyst, extending its operational life and maintaining its activity
3Object-generated harmful factors
If SCR is used to achieve NOx reductions in excess of 90%, then NOx emissions are significantly reduced, but ammonia infrastructure is lacking and ammonia release into the environment is a concern
Solution Approach 1:
The fuel cell uses components already present in the diesel exhaust (CO, unburned hydrocarbons, and oxygen) as reactants to generate electricity and clean the exhaust. This self-service approach eliminates the need for external ammonia supply infrastructure, using readily available exhaust components instead
Solution Approach 2:
The fuel cell converts harmful exhaust components (CO, unburned hydrocarbons, and oxygen) into useful electrical energy while simultaneously reducing NOx. This process eliminates the need for separate ammonia-based SCR systems and their associated infrastructure, using the exhaust's own components beneficially
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 achieves significant reduction in NOx and particulate matter emissions, meeting stringent emission limits without compromising engine efficiency, and provides a reliable and environmentally friendly power generation solution for vehicles.
Implementation Method 1
an intermediate temperature solid oxide fuel cell to treat exhaust gases, reducing NOx and particulate matter emissions
Implementation Method 2
reducing catalyst for removing nitrogen oxides from the exhaust
Implementation Method 3
oxidation catalyst for further emissions control
Implementation Method 4
external exhaust gas recirculation to control adiabatic flame temperature
Data Source
AI summary
One aspect of the invention relates to a power generation system that has an internal combustion engine that operates in a low temperature combustion mode to produce an engine exhaust that is low in NOx and particulate matter. The exhaust is treated by a fuel cell to remove organic compounds and CO while producing useful power. Another aspect of the invention relates to controlling the adiabatic flame temperature by EGR drawing from upstream of the fuel cell. A further aspect of the invention relates to treating engine exhaust with a reducing catalyst and then with a fuel cell. A still further aspect of the invention relates to treating exhaust with an intermediate temperature solid oxide fuel cell. A further aspect of the invention relates to a system equipped with a valve allowing exhaust to selectively bypass a fuel cell.