Catalytic Converter Insulating Layer Cold Start Purification
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Solution Overview
Problem
Internal combustion engines, particularly gasoline direct injection engines, face challenges in removing harmful materials like hydrocarbons from exhaust gases during initial starting due to low exhaust gas temperatures, which are below the activation temperature of traditional catalytic converters, leading to incomplete purification and discharge of pollutants.
Innovation Solution
A catalytic converter design featuring a multi-layered structure with a three-way catalyst layer, a hydrocarbon trap layer, and an insulating layer, where the insulating layer prevents heat transfer to the hydrocarbon trap layer by moisture adsorption, allowing the hydrocarbon trap layer to absorb hydrocarbons at low temperatures and release them when the catalyst reaches activation temperature, ensuring effective purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional catalytic converter is used, then the structure is simple, but harmful materials including hydrocarbons cannot be effectively removed at initial starting due to low exhaust gas temperature
Solution Approach 1:
The catalytic converter is divided into multiple functional layers: a hydrocarbon trap layer for capturing hydrocarbons at low temperatures, a three-way catalyst layer for oxidizing harmful materials, and an insulating layer for thermal management. This segmentation allows each layer to perform its specific function effectively, solving the problem of incomplete purification at cold start while maintaining manageable structural complexity.
Solution Approach 2:
The hydrocarbon trap layer performs preliminary action by capturing and storing hydrocarbons from the exhaust gas before the three-way catalyst layer becomes active. This preliminary capture ensures that hydrocarbons are removed even when the main catalyst is not yet activated due to low temperatures, addressing the cold start purification problem.
2Productivity
If the hydrocarbon trap layer is heated quickly, then hydrocarbons can be released for purification, but the three-way catalyst layer cannot reach activation temperature in time
Solution Approach 1:
The insulating layer acts as an intermediary between the hydrocarbon trap layer and the three-way catalyst layer. It controls heat transfer to prevent direct thermal coupling, allowing the hydrocarbon trap layer to be heated independently for rapid hydrocarbon release while the three-way catalyst layer is heated separately to reach its activation temperature, resolving the temperature conflict.
Solution Approach 2:
Different regions of the catalytic converter have different thermal properties. The insulating layer provides thermal isolation in specific regions, creating localized temperature zones that allow the hydrocarbon trap layer to be heated quickly for hydrocarbon release while the three-way catalyst layer maintains its own heating trajectory to reach activation temperature, addressing the conflicting temperature requirements.
3Object-affected harmful factors
If additional catalytic converters are mounted to improve purification, then harmful material removal increases, but the system complexity and cost increase
Solution Approach 1:
Multiple catalytic functions are merged into a single integrated catalytic converter unit. The hydrocarbon trap layer, three-way catalyst layer, and insulating layer are combined in one device, eliminating the need for separate catalytic converters and reducing overall system complexity while maintaining comprehensive purification capabilities.
Solution Approach 2:
The catalytic converter is designed with multi-functionality to handle various purification tasks simultaneously: the hydrocarbon trap layer captures hydrocarbons, the three-way catalyst layer oxidizes harmful materials, and the insulating layer manages thermal conditions. This universal design consolidates multiple functions into one device, reducing system complexity compared to using separate specialized converters.
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 design effectively purifies harmful materials, including hydrocarbons, at initial engine start-ups by retarding the temperature rise of the hydrocarbon trap layer until the three-way catalyst layer activates, improving exhaust gas purification efficiency and reducing particulate matter emissions.
Implementation Method 1
The insulating layer may prevent heat of the exhaust gas from being transferred to the hydrocarbon trap layer by moisture adsorption.
Implementation Method 2
a hydrocarbon trap layer and an insulating layer... allowing the hydrocarbon trap layer to absorb hydrocarbons at low temperatures
Implementation Method 3
converting harmful material such as carbon monoxide, hydrocarbon, and nitrogen oxide contained in the exhaust gas into harmless material through oxidation-reduction reaction
Data Source
AI summary
A catalytic converter of an internal combustion engine may include: at least one inlet channel having an end through which an exhaust gas is flowed into and the other end which is blocked; at least one outlet channel having an end which is blocked and the other end through which the exhaust gas is discharged; and a wall defining a boundary between neighboring inlet channel and outlet channel, and adapted to flow the exhaust gas from the inlet channel to the outlet channel, wherein the wall includes a single-layered portion formed at an end portion and having a three-way catalyst layer, and a multi-layered portion being the portion other than the single-layered portion and having a three-way catalyst layer, a hydrocarbon trap layer and an insulating layer. An apparatus of purifying an exhaust gas is also provided.