Separator With Variable Aperture And Impaction Surface
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Solution Overview
Problem
Conventional separators for blow-by gas in reciprocating engines face challenges in achieving high efficiency without moving parts or electrical power, while also maintaining acceptable crankcase pressure and particle separation efficiency, especially for smaller particles.
Innovation Solution
A separator system with a first chamber, a second chamber, and a pump that generates a pressure differential to maintain high separation efficiency without increasing inlet pressure, using an actuator to adjust the aperture cross-sectional area and an impaction surface to deflect the fluid stream, allowing for efficient separation of contaminants without electrical power or complex parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional separator is used to separate contaminants from blow-by gas, then the separation efficiency is limited, but the device complexity and cost increase if powered centrifugal separators or electrostatic precipitators are used
Solution Approach 1:
The patent replaces complex mechanical separation systems (powered centrifugal separators, electrostatic precipitators) with a passive inertial impactor system that uses the natural inertia of particles and gas flow dynamics to achieve high separation efficiency without moving parts or electrical power
Solution Approach 2:
The separator uses the kinetic energy and inertia of the blow-by gas flow itself to perform the separation function, requiring no external power source or active control systems. The system serves itself by utilizing the inherent properties of the fluid stream
2Manufacturing precision
If the nozzle cross-sectional area is reduced to increase fluid velocity and separation efficiency, then the separation efficiency improves, but the pressure drop increases and crankcase pressure rises to unacceptable levels
Solution Approach 1:
The patent employs a variable cross-sectional area nozzle design where the aperture changes dynamically along the flow path. The aperture is largest at the inlet to minimize pressure drop, then constricts to a smallest cross-sectional area (throat) to maximize fluid velocity and separation efficiency, then expands again downstream to recover pressure and prevent crankcase pressure buildup
Solution Approach 2:
The nozzle geometry parameters (cross-sectional area) are strategically varied along the flow direction to optimize both separation efficiency and pressure management. The aperture transitions from large to small and then expands, creating optimal velocity profiles for particle separation while maintaining acceptable pressure levels
3Manufacturing precision
If filter mediums are used to remove oil and soot from blow-by gas, then the filtration efficiency improves, but the filters become clogged and require periodic replacement
Solution Approach 1:
The patent extracts the contaminants from the blow-by gas stream through inertial separation at the impactor surface, removing oil, soot, and other particles without using filter mediums that would become clogged. The separated contaminants are collected and removed from the system
Solution Approach 2:
The patent avoids using expensive filter mediums with limited lifespans by employing a durable inertial impactor system with no consumable filtering elements. The separator structure itself is robust and requires no replacement, making it suitable for long-term engine operation
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 achieves high separation efficiency for contaminants, maintaining acceptable crankcase pressure and effectively separating particles as small as 0.2 microns, with a gravimetric separation efficiency of 95-98% for particles greater than or equal to 0.3 μm, and can be integrated into crankcase ventilation systems to prevent oil loss and engine damage.
Implementation Method 1
a pump arranged to generate a pressure differential across the aperture to draw the first fluid stream through the aperture
Implementation Method 2
an impaction surface coupled to the second chamber arranged to deflect the first fluid stream after the first fluid stream enters the second chamber such that contaminants are separated from the first fluid stream
Data Source
AI summary
A separator for separating contaminants from a fluid stream has first and second chambers coupled by an aperture through which fluid can pass. An actuator can adjust the crossectional area of the aperture according to a pressure differential between the first chamber and a pressure reference. An impaction surface can deflect the first fluid stream after it enters the second chamber such that contaminants are separated from the stream. A pump generates a pressure differential across the aperture. It includes a third chamber having a second inlet for receiving a second fluid stream into the third chamber. The second inlet includes a convergent nozzle for accelerating the second fluid stream, and a third inlet for receiving the first fluid stream downstream of the impaction surface, the third inlet being arranged relative to the second inlet such that the second fluid stream can entrain and accelerate the first fluid stream.