Oxidation Catalyst Deterioration Detection via Oxygen Difference
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Solution Overview
Problem
Existing methods for determining the deterioration of oxidation catalysts in engine exhaust systems, which exhibit both oxidation and adsorption/desorption characteristics, are inadequate, particularly for diesel engines with low emission temperatures, as they fail to accurately differentiate between the deterioration of catalytic and adsorption substances, leading to inefficient emission purification.
Innovation Solution
A device and method that calculate the difference in oxygen concentration between upstream and downstream of an oxidation catalyst at various temperatures to determine deterioration, distinguishing between the adsorption and catalytic substances' performance, and adjusting thresholds based on provisional determinations to accurately assess purifying efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If temperature monitoring technique is used to determine catalyst deterioration, then the monitoring method is simple, but it cannot accurately determine deterioration of oxidation catalysts with adsorption/desorption characteristics
Solution Approach 1:
The invention changes the measurement parameter from temperature monitoring to oxygen concentration difference measurement. By measuring the difference in oxygen concentration between upstream and downstream of the catalyst at multiple temperatures, the system can accurately determine both adsorption substance deterioration and catalytic substance deterioration, resolving the inaccuracy problem while maintaining operational simplicity through automated sensor-based measurement.
Solution Approach 2:
The invention segments the deterioration determination into two distinct parts: adsorption substance deterioration (determined by oxygen concentration difference at temperatures below desorption initiation) and catalytic substance deterioration (determined by oxygen concentration difference at temperatures above oxidation initiation). This segmentation allows each component's deterioration to be measured independently and accurately.
2Measurement precision
If specific control technique is used for deterioration determination, then the determination accuracy is improved, but the system complexity increases
Solution Approach 1:
The invention makes the oxygen concentration sensors serve multiple functions: they monitor both adsorption substance performance (at lower temperatures) and catalytic substance performance (at higher temperatures) using the same hardware setup. This multi-functionality achieves accurate deterioration determination without increasing device complexity, as the same sensors and processing system handle both measurement tasks.
3Ease of operation
If single temperature measurement is used, then the measurement process is simple, but it cannot differentiate between adsorption and catalytic substance deterioration
Solution Approach 1:
The invention introduces dynamic temperature variation into the measurement process. By measuring oxygen concentration differences at multiple temperatures (below desorption initiation temperature and above oxidation initiation temperature), the system dynamically adapts the measurement conditions to distinguish between adsorption and catalytic substance deterioration, thereby preserving complete diagnostic information while maintaining procedural simplicity through automated multi-temperature measurement.
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
This approach allows for precise detection of changes in oxidation and adsorption performance, effectively determining the deterioration of oxidation catalysts and maintaining emission purification efficiency by differentiating between zeolite and precious metal catalyst deterioration.
Implementation Method 1
the adsorption substance adsorbs HCs at a low temperature of the catalyst
Implementation Method 2
a catalytic substance capable of oxidizing the exhaust component
Implementation Method 3
the catalytic substance... to be oxidized by the catalytic substance and eliminated
Implementation Method 4
At a high temperature of the catalyst, adsorbed HCs are desorbed from the catalyst to be oxidized
Data Source
AI summary
A catalyst determining device includes an oxidation catalyst (31) disposed in an outlet passage (22) in an engine (10), the oxidation catalyst (31) including an adsorption substance for adsorbing and desorbing an exhaust component in exhaust and a catalytic substance capable of oxidizing the exhaust component, a calculating unit (2b) for calculating a difference (∆C) in oxygen concentration between upstream and downstream of the oxidation catalyst (31), and a determination unit (3) for determining the deterioration of the oxidation catalyst (31) through comparison of a plurality of the differences (∆C) in oxygen concentration obtained at different temperatures (T) of the oxidation catalyst (31) by the calculating unit (2b).