Catalytic Muffler Crossover Passageway Secondary Air
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Solution Overview
Problem
Catalytic converters for small internal combustion engines are costly due to the high cost of catalysts, and there is a need for a compact and cost-effective solution to reduce exhaust emissions.
Innovation Solution
A catalytic muffler design that integrates a catalyst chamber with an upstream chamber and a passageway for secondary air, allowing for efficient mixing and treatment of exhaust gases without a separate secondary air inlet, thereby reducing the need for additional components and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a catalytic converter is integrated with a muffler into a single unit, then the overall size and component count are reduced, but the cost of the catalytic converter increases due to additional design complexity
Solution Approach 1:
The patent combines the catalytic converter and muffler into a single integrated unit, merging two separate components (catalyst chamber and muffler chamber) into one device. This reduces the overall volume and eliminates the need for separate mounting brackets, hoses, and connection points that would be required if the components were separate.
Solution Approach 2:
The integrated catalytic muffler performs multiple functions simultaneously: it acts as both a catalytic converter (treating exhaust emissions through chemical reactions) and a muffler (reducing noise through acoustic absorption and reflection). The single device thus serves dual purposes that would traditionally require separate components.
2Productivity
If secondary air is introduced through a separate inlet, then the oxidation reaction efficiency is improved, but the number of components and manufacturing cost increase
Solution Approach 1:
The exhaust outlet serves a dual function: it discharges treated exhaust gases during normal operation and simultaneously acts as the secondary air inlet during oxidation reactions. This eliminates the need for a separate secondary air inlet component, reducing manufacturing complexity and cost while maintaining the ability to introduce secondary air for efficient oxidation.
Solution Approach 2:
The direction of air flow through the exhaust outlet dynamically reverses based on operating conditions. During normal exhaust operation, gases flow out through the outlet; during oxidation reactions, secondary air is drawn in through the same outlet. This dynamic bidirectional flow capability eliminates the need for separate inlet and outlet ports.
3Ease of manufacture
If catalyst quantity is reduced to decrease cost, then manufacturing cost is reduced, but emission treatment effectiveness decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst formulation to create a more cost-effective catalyst recipe that maintains treatment effectiveness. Additionally, the secondary air injection parameter is optimized to enhance oxidation efficiency, allowing for reduced catalyst quantity while maintaining or improving emission treatment performance.
Solution Approach 2:
The system introduces secondary air containing oxygen to accelerate the oxidation of carbon monoxide and hydrocarbons in the exhaust gases. This enhanced oxidation process compensates for reduced catalyst quantity by providing additional oxygen directly to the reaction zone, maintaining treatment effectiveness with less expensive catalyst material.
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 integrated design effectively treats exhaust emissions by utilizing secondary air for oxidation reactions, reducing costs and enhancing emission reduction capabilities while maintaining compactness.
Implementation Method 1
a catalyst disposed in the catalyst chamber
Implementation Method 2
utilizing secondary air for oxidation reactions
Data Source
AI summary
A catalytic muffler that treats the exhaust gases of an internal combustion engine. The catalytic muffler includes a catalyst chamber, a catalyst disposed in the catalyst chamber, an upstream chamber disposed upstream of the catalyst, an exhaust inlet configured to receive exhaust gases, an exhaust outlet configured to discharge converted gases converted by the catalyst to the atmosphere, and further configured to receive secondary air, and a passageway communicating between the exhaust outlet and the upstream chamber, and configured to provide the secondary air received by the exhaust outlet to the upstream chamber.