Three-Dimensional Catalyst Substrate for Exhaust Gas Mixing and Light-Off
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Solution Overview
Problem
Existing diesel engine aftertreatment systems face challenges in achieving catalyst light-off temperature, urea decomposition limitations, contamination from recirculated exhaust gases, and packaging constraints due to conventional honeycomb structures, which impact fuel efficiency, emission control, and system operation.
Innovation Solution
An exhaust treatment apparatus with a three-dimensional open structure catalyst substrate in the exhaust manifold, allowing for earlier reductant introduction and improved mixing, reducing light-off time, and enabling closer coupling of aftertreatment devices, while minimizing backpressure and utilizing existing packaging space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation is used to reduce nitrogen oxide emissions, then emission control is improved, but hydrocarbons and particulates in the exhaust gases cause contamination and durability issues within the engine
Solution Approach 1:
The catalyst substrate is divided into two distinct regions: a first region with catalyst for treating hydrocarbons and particulates, and a second region without catalyst for clean exhaust gas recirculation. This segmentation allows different functions in different zones of the same component.
Solution Approach 2:
The catalyst substrate acts as an intermediary between the exhaust stream and the recirculation system. It cleans the exhaust gases by converting hydrocarbons and particulates before recirculation, while still allowing nitrogen oxides to pass through for EGR.
2Ease of manufacture
If conventional honeycomb structures are used for catalysts, then catalyst function is provided, but packaging space is increased and additional post-turbocharger DOC is required
Solution Approach 1:
The EGR catalyst and pre-turbocharger DOC are merged into a single integrated substrate structure. The first region provides DOC function while the second region enables EGR, eliminating the need for separate components and reducing overall packaging space.
Solution Approach 2:
The single catalyst substrate performs multiple functions: it acts as a DOC in the first region for hydrocarbon and particulate oxidation, and as an EGR catalyst in the second region for enabling clean exhaust gas recirculation. This multi-functionality reduces the number of separate components needed.
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 solution accelerates catalyst light-off, enhances reductant evaporation and mixing, reduces contamination, and optimizes packaging, leading to improved fuel efficiency and emission control across a wider range of operating conditions.
Implementation Method 1
The DOC uses oxygen in the exhaust gases to convert carbon monoxide (CO) to carbon dioxide (CO2); and to convert hydrocarbons (HC) to water (H2O) and (CO2)
Implementation Method 2
the catalyst has a three-dimensional open structure which permits flow of exhaust gases from said plurality of exhaust gas inlets to said exhaust gas outlet
Implementation Method 3
The reductant and exhaust gases flow through the turbocharger together and this can promote evaporation and mixing through the turbocharger
Implementation Method 4
promote evaporation and mixing through the turbocharger
Data Source
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AI summary
The present invention relates to an exhaust treatment apparatus (1) for an internal combustion engine (5). The apparatus includes a catalyst chamber (15) containing a catalyst (35). One or more exhaust gas inlets (11 A-D) are provided for supplying exhaust gases from the internal combustion engine (5) to the catalyst chamber (C). An exhaust gas outlet (21) for supplying exhaust gases from the catalyst chamber to a turbocharger (25). An injection nozzle (19) is provided for introducing a reductant (23) into the exhaust gases between the catalyst (15) and the turbocharger (25). The reductant (23) and the exhaust gases can undergo mixing as they pass through the turbocharger (25). The catalyst (15) can have a three-dimensional open structure to facilitate the flow of exhaust gases. The invention also relates to a method of treating exhaust gases from an internal combustion engine (5).