Compact Ejector for Boosted Engine Vapor Purge
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Solution Overview
Problem
Prior vapor purge systems for boosted internal combustion engines, such as those with turbochargers, face challenges due to increased pressure which reduces the effectiveness of the ejector's ability to create a vacuum for purging, leading to inefficiencies and potential interference with engine performance, and require complex manufacturing processes resulting in bulky and less-than-ideal flow characteristics.
Innovation Solution
A compact and efficient ejector design featuring a venturi tube with a converging and diverging section, coupled with a flange and two tubes, which are affixed using welding or snap fit connectors, optimizing geometry and reducing the need for separate molding and pins, thereby improving flow characteristics and manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional ejector design with separate molding and pins is used, then manufacturing complexity increases and device size increases, but flow rate and flow efficiency deteriorate due to bulky geometry and poor flow characteristics
Solution Approach 1:
The patent combines multiple ejector components into a single integrated molding that includes the body, throat, and pins as one unified structure. This eliminates the need for separate assembly steps and reduces manufacturing complexity while optimizing the internal geometry for improved flow characteristics and higher flow rate.
Solution Approach 2:
The patent employs curved and streamlined geometries in the ejector design, particularly in the throat region and flow paths, to reduce flow separation and improve flow efficiency. The optimized curvature profiles enhance fluid dynamics performance compared to traditional angular or straight-line designs.
2Productivity
If a traditional ejector design with separate molding and pins is used, then manufacturing complexity increases, but flow efficiency deteriorates due to bulky geometry and poor flow characteristics
Solution Approach 1:
The patent combines multiple ejector components into a single integrated molding that includes the body, throat, and pins as one unified structure. This eliminates the need for separate assembly steps and reduces manufacturing complexity while optimizing the internal geometry for improved flow characteristics and higher flow rate.
Solution Approach 2:
The patent employs curved and streamlined geometries in the ejector design, particularly in the throat region and flow paths, to reduce flow separation and improve flow efficiency. The optimized curvature profiles enhance fluid dynamics performance compared to traditional angular or straight-line designs.
3Volume of moving object
If a compact ejector design is used, then device size decreases and assembly steps are reduced, but maintaining tight tolerances and flow efficiency becomes more challenging
Solution Approach 1:
The patent combines multiple ejector components into a single integrated molding that includes the body, throat, and pins as one unified structure. This eliminates the need for separate assembly steps and reduces manufacturing complexity while optimizing the internal geometry for improved flow characteristics and higher flow rate.
Solution Approach 2:
The patent optimizes geometric parameters such as throat diameter, length-to-diameter ratio, and angle of convergence to achieve the desired flow rate and vacuum generation within a compact form factor. These parameter adjustments maintain manufacturing precision while reducing overall ejector size.
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 new ejector design achieves a 25% greater flow rate over the boost range compared to prior art, is more compact, and simplifies manufacturing, reducing weight and assembly steps while maintaining tight tolerances and improved flow efficiency.
Implementation Method 1
a tube with a throat (reduced diameter section) causes a higher flowrate which causes the vacuum
Implementation Method 2
In boosted engines, i.e., turbocharged, supercharged, or boosted by any suitable device, pressure in the engine's intake is often above atmospheric thereby reducing the available times for purging. To obtain a vacuum to drive purge flow
Data Source
AI summary
Vapors in the fuel tank of a vehicle are collected in a carbon canister. An ejector or aspirator is used to purge the carbon canister in a pressure-charged engine in which a positive pressure exists in the intake. A compact ejector includes a substantially planar flange and a venturi tube coupled to the flange with a central axis of the venturi tube substantially parallel to the flange. By mounting the ejector on an intake component, having the venturi tube on the inside of the intake component, and having the venturi tube parallel to the flange yields a very compact package and protects the ejector from damage from other engine components.