Exhaust Assembly Catalytic Converter Flow Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The parallel arrangement of hydrolysis and oxidation catalytic converters in the pre-silencer leads to uneven exhaust gas flow, resulting in excessive NO2 production and incomplete conversion of reducing agents, causing harmful fission products like isocyanic acid or cyanuric acid solid particles.
Innovation Solution
The oxidation catalytic converter is arranged in a ring around the hydrolysis catalytic converter within a common housing, ensuring each converter receives a defined exhaust gas flow, with the hydrolysis catalytic converter having a dedicated injection section for the reducing agent, which is evaporated in the upstream tubular section, and the gas streams are mixed in a long section before passing through additional catalytic converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If hydrolysis and oxidation catalytic converters are arranged in parallel in the pre-silencer, then both converters can be installed in a compact space, but the exhaust gas flow becomes uneven leading to excessive NO2 production and incomplete conversion of reducing agents
Solution Approach 1:
The exhaust system is divided into separate exhaust gas substreams, with each catalytic converter processing a defined portion of the exhaust flow. The oxidation catalytic converter is assigned a first exhaust gas substream while the hydrolysis catalytic converter handles a second exhaust gas substream, ensuring uniform flow distribution and preventing the harmful effects of mixed flow patterns.
2Productivity
If oxidation catalytic converter converts NO to NO2 in parallel arrangement, then nitrogen oxide reduction is enhanced, but harmful fission products like isocyanic acid and cyanuric acid solid particles are produced due to incomplete reducing agent conversion
Solution Approach 1:
The oxidation catalytic converter is extracted from the parallel arrangement and repositioned to process a separate exhaust gas substream upstream of the hydrolysis catalytic converter. This extraction eliminates the interaction between the two converters that caused incomplete reducing agent conversion and harmful fission product formation, while maintaining effective NO to NO2 conversion.
3Productivity
If reducing agent is injected into parallel arranged catalytic converters, then ammonia production is enhanced, but harmful by-products form due to uneven flow and incomplete conversion
Solution Approach 1:
The reducing agent injection is localized to specific zones within the exhaust system. The injection occurs in regions with defined flow characteristics upstream of the hydrolysis catalytic converter, ensuring complete conversion to ammonia without forming harmful by-products. Each location has optimized injection parameters matched to the local flow 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
This arrangement ensures complete and defined conversion of NO to NO2 and efficient evaporation of the reducing agent, preventing harmful by-products and optimizing the performance of both catalytic converters.
Implementation Method 1
the oxidation catalytic converter (7) with which the nitrogen monoxide (NO) contained in the exhaust gas flowing through can be converted into nitrogen dioxide (NO 2)
Implementation Method 2
the hydrolysis catalytic converter (8) from which ammonia (NH 3) can be generated
Implementation Method 3
injected into the tubular section (4a) of the exhaust gas branch (4) and can be completely evaporated therein
Data Source
Figure 1
Figure 2
AI summary
The system has a hydrolysis catalyzer (8) that is attached with an oxidation catalyzer (7) in a common housing (11). An exhaust gas component string (3) with a tubular section (3a) encompasses a tubular section (4a) of an exhaust gas component string (4). A ring-shaped inflow area (12) serves as a heating chamber for the oxidation catalyzer. A reduction agent is injected in the tubular section (4a) of the exhaust gas component string (4), and ammonia is produced by using the hydrolysis catalyzer.