Mass Airflow Sensor Duct With Hydrocarbon Trap and Guide Vanes
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Solution Overview
Problem
Existing air intake systems for internal combustion engines fail to effectively prevent evaporative hydrocarbon emissions after engine shutdown without causing significant airflow restriction or material loss, which affects engine performance and air quality.
Innovation Solution
A combined mass airflow sensor and hydrocarbon trap system that includes a duct with ports and a hydrocarbon absorbing sheet, supported by a housing and guide vanes, to capture evaporative emissions while maintaining low airflow resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrocarbon vapor-adsorbing materials are combined with conventional air filters, then evaporative emissions are absorbed, but the vapor-adsorbing materials flake out and enter the air intake system
Solution Approach 1:
The patent employs a foam core structure with porous characteristics that provides mechanical support for the hydrocarbon-adsorbing material. The foam core prevents the adsorbing material from flaking while maintaining its vapor absorption capability, resolving the contradiction between emission control and material stability.
Solution Approach 2:
The invention creates a composite structure combining foam core material with hydrocarbon-adsorbing material. This composite design integrates the structural integrity of foam with the functional properties of the adsorbing material, preventing flaking while maintaining emission absorption effectiveness.
2Object-generated harmful factors
If secondary hydrocarbon adsorbing filters are placed across the airflow path, then evaporative emissions are prevented from exiting, but airflow restriction increases and engine efficiency decreases
Solution Approach 1:
The hydrocarbon-adsorbing material is positioned specifically within the housing structure rather than across the entire airflow path. This localized placement allows the material to capture evaporative emissions while minimizing interference with the main airflow, thus preserving engine efficiency.
Solution Approach 2:
The foam core acts as an intermediary structure that supports the hydrocarbon-adsorbing material while allowing airflow to pass through. This intermediary structure enables the adsorbing material to function without creating significant flow restriction, resolving the contradiction between emission control and engine performance.
3Measurement precision
If guide vanes are added to reduce air turbulence, then airflow measurement accuracy improves, but device complexity increases
Solution Approach 1:
The guide vanes are integrated into the existing housing structure rather than being added as separate components. This merging approach reduces device complexity by combining multiple functions into a unified structure, while still achieving the goal of reducing air turbulence and improving measurement accuracy.
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
Effectively captures evaporative hydrocarbons without increasing airflow restriction, ensuring engine efficiency and accurate airflow measurement by reducing turbulence.
Implementation Method 1
A hydrocarbon trap is provided for absorbing evaporative hydrocarbon emissions from an air intake duct of an internal combustion engine
Implementation Method 2
A port in the housing is configured to support a mass airflow sensor within the duct
Implementation Method 3
At least one guide vane extends across an interior of the duct adjacent to the mass airflow sensor and is configured to reduce air turbulence within the airstream passing through the duct
Data Source
Figure 1~2
Figure 3~4
Figure 5~5A
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.