Exhaust Pipe Standing Wave Geometry for Particle Coagulation
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Solution Overview
Problem
Submicron particles emitted from vehicle exhausts, particularly from Diesel engines, pose health and environmental risks due to their small size, which allows them to penetrate the respiratory system and linger in the air, necessitating a method to group these particles into larger, filterable sizes to reduce their number.
Innovation Solution
An exhaust pipe with a standing wave geometry is designed to group submicron particles into larger filterable particles by creating a velocity field with periodic changes in gas flow velocity, accelerating and decelerating particles based on their size, leading to their coagulation and formation of larger particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If submicron particles are emitted directly from exhaust pipes, then the exhaust system is simple, but the health and environmental risk increases due to particle penetration and longevity in air
Solution Approach 1:
The patent applies acoustic resonance (a form of mechanical vibration) within the exhaust pipe to create oscillating gas flow that promotes particle coagulation. The pipe geometry is designed to resonate at specific frequencies, generating standing waves that enhance particle grouping without requiring external energy input or complex additional devices.
Solution Approach 2:
The patent changes the physical parameters of the exhaust system by designing a specific pipe geometry with varying cross-sectional area along its length. This geometric parameter change creates regions of different flow velocities that promote particle coagulation, transforming the exhaust system from a simple conduit to a particle-aggregation device.
2Productivity
If the exhaust pipe uses a straight geometry, then the device is simple to manufacture, but particle grouping efficiency is reduced
Solution Approach 1:
The patent employs curved and varying cross-sectional geometry in the exhaust pipe rather than a straight cylindrical shape. The pipe features regions of expanding and contracting cross-section that create the necessary flow conditions for particle coagulation, utilizing curvature and geometric variation to achieve the desired aerodynamic effects.
Solution Approach 2:
The pipe geometry is designed with periodic variations in cross-sectional area along its length, creating alternating regions of high and low flow velocity. This periodic geometric structure induces corresponding periodic variations in gas flow velocity, which enhances particle coagulation efficiency.
3Productivity
If acoustic resonance is used to promote particle coagulation, then particle grouping increases, but energy consumption increases
Solution Approach 1:
The exhaust pipe design enables the exhaust gas flow itself to generate the acoustic resonance required for particle coagulation. The system utilizes the kinetic energy already present in the exhaust flow to create the necessary oscillations, rather than requiring external energy input. The pipe geometry acts as a resonator that converts the exhaust flow's own energy into productive coagulation-promoting vibrations.
Solution Approach 2:
The patent employs acoustic resonance (a form of mechanical vibration) within the exhaust pipe to create oscillating gas flow that promotes particle coagulation. The pipe geometry is designed to resonate at specific frequencies, generating standing waves that enhance particle grouping without requiring external energy input or complex additional devices.
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 solution significantly increases the number of filterable particles while reducing submicron particles, as demonstrated by experimental results showing a decrease in smaller particles and an increase in larger mass fractions, effectively mitigating health and environmental risks.
Implementation Method 1
the internal surface is shaped to form standing cyclic wave geometry having at least 2 cycles
Implementation Method 2
a velocity field with periodic changes in gas flow velocity, accelerating and decelerating particles based on their size
Implementation Method 3
leading to their coagulation and formation of larger particles
Implementation Method 4
a substantial amount of the inhalable particles are grouped to form filterable particles while flowing inside the exhaust pipe
Data Source
Figure 1
Figure 2~3b
Figure 4a~4b
AI summary
An exhaust pipe (100) for a fuel burning engine including a hollow body, the body having an internal surface (120), an external surface (110), a first open end (130), a second open end (140) and a longitudinal axis, wherein the internal surface (120) is shaped to form standing cyclic wave geometry having at least 2 cycles (c). When gas containing inhalable particles (22) enters the exhaust pipe (100) through the first open end (130) and flows out of the exhaust pipe (100) through the second open end (140), a substantial amount of inhalable particles (22) are grouped to form filterable particles (182).