Mass Airflow Sensor Duct With Hydrocarbon Trap and Low Turbulence
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Solution Overview
Problem
Existing air intake systems for internal combustion engines struggle to effectively absorb evaporative hydrocarbon emissions without causing airflow resistance, which can negatively impact engine efficiency.
Innovation Solution
A combined mass airflow sensor and hydrocarbon trap system that includes a duct communicating an airstream from an air filter to the air intake duct, with ports to draw in hydrocarbon emissions and a housing supporting hydrocarbon absorbing sheets, designed to maintain airflow efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrocarbon adsorbing filters are placed directly across the airflow path, then evaporative hydrocarbon emissions are eliminated, but airflow resistance increases causing reduced engine efficiency
Solution Approach 1:
The hydrocarbon trap is divided into separate functional zones: a first section with hydrocarbon adsorbing material for emission control, and a second section as a clean airflow passage. This segmentation allows the harmful hydrocarbon absorption function to be separated from the main airflow path, eliminating emissions without creating airflow resistance that would reduce engine efficiency.
Solution Approach 2:
The hydrocarbon adsorbing material is extracted from the main airflow path and placed in a separate first section of the trap. The second section provides an unobstructed airflow path, thus extracting the emission control function from the airflow resistance problem while maintaining both functions independently.
2Object-generated harmful factors
If hydrocarbon adsorbing materials are combined with conventional air filters, then evaporative emissions are absorbed, but the materials may flake out and enter the air intake system
Solution Approach 1:
The trap is segmented into a first section containing the hydrocarbon adsorbing material and a second section providing clean airflow. This physical separation prevents the adsorbing material from contacting the airflow and potentially flaking into the engine, while still maintaining the emission absorption function in the first section.
Solution Approach 2:
The hydrocarbon adsorbing material is extracted from direct contact with the airflow path and confined to the first section. This extraction eliminates the reliability issue of material flaking into the air intake system while preserving the emission control function.
3Object-generated harmful factors
If the internal pressure in the intake manifold increases after engine shutdown, then evaporative hydrocarbons may leak out, but adding filtration layers increases flow restriction
Solution Approach 1:
The trap structure is segmented into two distinct sections: the first section with hydrocarbon adsorbing material that activates when pressure increases to absorb leaking hydrocarbons, and the second section maintaining open airflow. This segmentation provides emission control during pressure increases without adding restrictive filtration layers to the main airflow path.
Solution Approach 2:
The hydrocarbon trap performs multiple functions: during normal operation it allows free airflow through the second section, and during engine shutdown with increased pressure it absorbs evaporative hydrocarbons in the first section. This multi-functionality addresses both emission control and airflow requirements without increasing device complexity.
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 system effectively absorbs evaporative hydrocarbon emissions while maintaining low airflow resistance, thus enhancing engine efficiency and reducing environmental pollution.
Implementation Method 1
a hydrocarbon absorbing sheet disposed between the duct and the housing
Implementation Method 2
the mass airflow sensor is a hot wire anemometer
Data Source
AI summary
A combined mass airflow sensor and hydrocarbon trap is provided for absorbing evaporative hydrocarbon emissions from an air intake duct of an internal combustion engine. The combined mass airflow sensor and hydrocarbon trap comprises a duct that supports a hydrocarbon absorbing sheet in an unfolded configuration within a housing. The duct communicates an airstream from an air filter to the air intake duct during operation of the internal combustion engine. An opening in the housing receives a mass airflow sensor into the duct, such that the mass airflow sensor is disposed within the airstream. Guide vanes extending across the duct reduce air turbulence within the airstream passing by the mass airflow sensor. Ports disposed along the duct allow the evaporative hydrocarbon emissions to be drawn into the interior and arrested by the hydrocarbon absorbing sheet when the internal combustion engine is not operating.