Integrated Diesel Exhaust Catalyst for Space-Constrained SCR Systems
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Solution Overview
Problem
Existing diesel engine exhaust gas cleaning systems require large installation space to achieve the necessary cleaning efficiency for nitrogen oxides, particularly in applications like construction and agricultural machinery where space is limited.
Innovation Solution
A device comprising a diesel oxidation catalyst, two ammonia addition devices, a catalytically activated particulate filter with a wall-flow filter substrate, and an SCR catalytic converter, where sensors monitor nitrogen oxide content to optimize the selective catalytic reduction of nitrogen oxides to nitrogen, allowing for improved cleaning efficiency and space savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diesel oxidation catalysts and SCR catalysts are used to achieve the required cleaning efficiency for nitrogen oxides, then the nitrogen oxide reduction is effective, but the installation space required is considerable
Solution Approach 1:
The patent combines the diesel oxidation catalyst and SCR catalyst into a single integrated catalyst unit with a baffle plate separating the two catalytic zones. The diesel oxidation catalyst section handles CO and HC oxidation, while the SCR catalyst section handles NOx reduction, allowing both functions to be performed in one compact device rather than requiring separate units.
Solution Approach 2:
The integrated catalyst unit performs multiple functions simultaneously: it oxidizes carbon monoxide, oxidizes hydrocarbons, and reduces nitrogen oxides all within a single device. The baffle plate configuration allows exhaust gas to sequentially pass through different catalytic zones, enabling one device to replace what would traditionally require multiple separate catalyst units.
2Reliability
If large exhaust gas cleaning units are used to achieve the required cleaning efficiency, then emission limits are met, but material costs and system complexity increase
Solution Approach 1:
The patent merges multiple catalytic functions into a single integrated unit with a unified housing and shared exhaust gas flow path. The baffle plate creates internal separation while maintaining a single external device structure, reducing the number of separate components that would need to be installed, maintained, and controlled independently.
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 configuration significantly enhances nitrogen oxide conversion rates, enabling compliance with emission limits while reducing the volume of the SCR catalytic converter, thus saving space and material costs, and optimizing the system's efficiency across varying exhaust gas temperatures and pollutant concentrations.
Implementation Method 1
a diesel oxidation catalyst (20) for the oxidation of carbon monoxide, hydrocarbons and nitrogen monoxide
Implementation Method 2
a catalytically activated particulate filter (40) comprising a wall-flow filter substrate which comprises a catalytically active material that promotes the selective catalytic reduction of nitrogen oxides to nitrogen
Implementation Method 3
the nitrogen oxides contained in the exhaust gas are reacted with ammonia in a comproportionation reaction to form harmless nitrogen
Implementation Method 4
a first sensor for determining the nitrogen oxide content in the exhaust gas to be cleaned is arranged in the direction of exhaust gas flow upstream or downstream of the diesel oxidation catalyst (20)
Implementation Method 5
the nitrogen oxides contained in the exhaust gas are reacted with ammonia in a comproportionation reaction to form harmless nitrogen
Data Source
Figure 1
Figure 2
Figure 3A~3B(I)
AI summary
The apparatus has an exhaust gas pipe (10), where a diesel oxidation catalyst is provided for oxidizing carbon monoxide, hydrocarbons and nitrogen monoxide. A device (30) is provided for the addition of ammonia or a compound in the exhaust gas to be purified, where the compound is decomposable to the ammonia. A catalytically activated particle filter is provided with a wall flow filter substrate which has a catalytically active material that conveys the selective catalytic reduction of nitrogen oxides to nitrogen. An independent claim is included for a method for the reduction of carbon monoxide, hydrocarbons, nitrogen oxides and soot particles in diesel engine exhaust gases.