Ammonia Slip Catalyst Oxygen Sensing for N2O and NH3 Slip Control
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Solution Overview
Problem
Existing exhaust aftertreatment systems face challenges in detecting and mitigating laughing gas (N2O) emissions and ammonia slip from ammonia slip catalysts, as these emissions are difficult to measure and can occur undetected, posing health and environmental risks.
Innovation Solution
A computer system that utilizes upstream and downstream oxygen concentration information, along with temperature and NOx concentration data, to determine the condition of an ammonia slip catalyst, enabling improved detection and quantification of N2O production and ammonia slip, and adjusts reductant injection to mitigate these emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ammonia slip catalyst is used to prevent ammonia slip emissions, then ammonia slip is reduced, but laughing gas (N2O) emissions increase
Solution Approach 1:
The system changes operational parameters (temperature, oxygen concentration, NOx levels) to identify N2O production conditions and adjusts reductant injection accordingly to mitigate N2O emissions while maintaining ammonia slip control
Solution Approach 2:
The system uses feedback from oxygen concentration measurements (upstream and downstream of ASC) and temperature data to detect N2O production conditions and adjusts reductant injection in response to these detected conditions
2Productivity
If reductant injection is increased to improve NOx conversion in SCR, then NOx conversion efficiency improves, but ammonia slip from ASC increases
Solution Approach 1:
The system dynamically adjusts reductant injection parameters based on detected N2O production conditions and ammonia slip risk, optimizing the balance between NOx conversion efficiency and ammonia slip prevention
Solution Approach 2:
The system uses feedback from oxygen concentration measurements and temperature data to detect conditions that may lead to excessive ammonia slip and adjusts reductant injection in response
3Measurement precision
If traditional emission detection methods are used, then common emissions can be monitored, but laughing gas and ammonia slip remain undetected
Solution Approach 1:
The system uses oxygen concentration measurements as an intermediary indicator to indirectly detect N2O production conditions, since direct N2O measurement is difficult. By measuring oxygen consumption in the ASC, the system infers N2O production without directly measuring it
Solution Approach 2:
The system replaces direct chemical measurement methods with indirect sensing using oxygen concentration sensors and temperature measurements, combined with computational analysis to detect N2O production conditions
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
Enhances the detection and mitigation of N2O and ammonia slip emissions by providing informed engine control decisions, reducing overall emissions through adaptive reductant management.
Implementation Method 1
an ammonia slip catalyst may be arranged downstream of the SCR component for further selective oxidation of ammonia into harmless nitrogen and water
Implementation Method 2
The SCR component brings a reductant, such as an urea or ammonia (NH3) solution, into reaction with NOx of the exhaust gases, leading to chemical reactions that convert NOx and ammonia to harmless nitrogen (N2) and water (H2O)
Implementation Method 3
a problem associated with ammonia slip catalysts may be that it can generate laughing gas (N2O)
Data Source
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AI summary
The present disclosure relates to a computer system (400) for determining a condition of an ammonia slip catalyst (101) of a vehicle (1), the computer system (400) comprising processing circuitry (402) configured to: - obtain upstream oxygen concentration information indicative of an oxygen concentration of exhaust gases upstream of said ammonia slip catalyst (101) and downstream oxygen concentration information indicative of an oxygen concentration of exhaust gases downstream of said ammonia slip catalyst (101); and [001] determine whether or not the ammonia slip catalyst (101) is in an N2O production condition based on said upstream oxygen concentration information and said downstream oxygen concentration information.