Segmented Inlet Baffle for Exhaust Mixer Backpressure

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Solution Overview

Problem

Configuring exhaust system components within limited packaging space while maintaining high mixing performance and minimizing backpressure generation is challenging, especially in compact mixer configurations used in emission reduction systems.

Innovation Solution

The mixer assembly includes a mixer shell with an inlet reactor and a baffle system that directs exhaust gas into two separate inlets and allows bypass flow, maximizing inlet flow area and using a swirl chamber for efficient mixing of diesel exhaust fluid and exhaust gas, thereby reducing backpressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a compact mixer configuration is used to save packaging space, then packaging efficiency is improved, but mixing performance may deteriorate and backpressure increases

Engineering Contradiction:

Improvemixer sizeVSAvoidmixing performance

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The mixer inlet is segmented into multiple pathways: a first inlet for primary exhaust gas flow, a second inlet for additional exhaust gas, and bypass openings for secondary flow. This segmentation allows compact packaging while maintaining adequate flow paths for mixing performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inlet baffle is divided into multiple sections (first, second, and third sections) arranged in different spatial dimensions around the mixer inlet. This multi-dimensional arrangement maximizes inlet flow area within a compact volume, directing flow through different pathways into the mixing chamber.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If a compact mixer configuration is used to save packaging space, then packaging efficiency is improved, but backpressure generation increases

Engineering Contradiction:

Improvemixer sizeVSAvoidbackpressure

Core Design Contradiction:

Volume of moving objectVSStress or pressure

Solution Approach 1:

The flow path is segmented into multiple channels including bypass openings that provide alternative routes for exhaust gas. This segmentation prevents flow congestion in a compact mixer, reducing backpressure while maintaining compact dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the inlet baffle have different properties: the first section directs flow through the first inlet, the second section directs flow through the second inlet, and the third section provides bypass openings. This local differentiation optimizes flow distribution to minimize backpressure in each region.

Inventive Principle:

Principle #3Local quality

3Productivity

If multiple inlet pathways are added to improve mixing performance, then mixing performance is improved, but device complexity increases

Engineering Contradiction:

Improvemixing performanceVSAvoidinlet configuration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Multiple inlet pathways (first inlet, second inlet, and bypass openings) are merged into a single integrated inlet baffle structure. This combining approach improves mixing performance through multi-pathway flow while avoiding the complexity of separate components for each inlet.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The inlet baffle serves multiple functions simultaneously: it directs flow through the first inlet, directs flow through the second inlet, and provides bypass openings. This multi-functionality achieves improved mixing performance without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This configuration achieves high mixing performance and minimizes backpressure generation, enabling efficient packaging and emission reduction in vehicle exhaust systems.

Implementation Method 1

The inlet baffle includes a first opening that directs exhaust gas into the first exhaust gas inlet, a scoop that directs exhaust gas into the second exhaust gas inlet

Methodology Applied

Scientific EffectFlow direction control:

Implementation Method 2

a plurality of bypass openings that direct exhaust gas to bypass entry into the inlet reactor

Methodology Applied

Scientific EffectBypass flow:

Implementation Method 3

The inlet reactor includes a swirl chamber that is comprised of at least a first flow element, a second flow element, and a third flow element that are fixed together to form an internal mixing cavity for injected fluid and exhaust gas

Methodology Applied

Scientific EffectSwirl mixing: Vortex Ring

Data Source

PatentUS11680507B2Inlet flow for high efficiency mixers

Publication Date: 2023.06.20 FAURECIA EMISSIONS CONTROL TECH USA LLC

AI summary

A mixer assembly for a vehicle exhaust system includes a mixer shell defining an internal cavity and an inlet reactor positioned within the internal cavity. The inlet reactor has a fluid inlet, a first exhaust gas inlet, and a second exhaust gas inlet. An inlet baffle is mounted to an upstream end of the mixer shell. The inlet baffle includes a first opening that directs exhaust gas into the first exhaust gas inlet, a scoop that directs exhaust gas into the second exhaust gas inlet, and a plurality of bypass openings that direct exhaust gas to bypass entry into the inlet reactor.