Exhaust Gas Treatment Device Baffle Plate Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust treatment systems for internal combustion engines face challenges with fluctuating NOx sensor readings, leading to less-than-optimal performance, and there is a need for compact, mechanically robust, and cost-effective SCR systems that provide representative NOx sensor data.
Innovation Solution
The exhaust gas treatment device features a housing with a selective catalytic substrate, an outlet tube extending through an outer wall, and a baffle plate that induces turbulence and mixing, optimizing the flow path to ensure accurate NOx sensor readings, while being compact and robust, with specific parameters for the baffle plate openings and outlet tube design to enhance mixing and reduce weight and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a long outlet tube is used to extend the mixing path, then mixing quality improves, but device volume and weight increase
Solution Approach 1:
The outlet tube is segmented into multiple sections with varying diameters. The first section has a larger diameter to accommodate the substrate outlet, while the second section has a smaller diameter to extend the residence time and mixing path length, achieving better mixing without proportionally increasing overall volume
Solution Approach 2:
A baffle plate is introduced to create a three-dimensional flow path within the outlet tube. The baffle plate forces the exhaust gas to follow a more complex trajectory, increasing the effective mixing path length and improving gas mixing without extending the linear length of the outlet tube
2Measurement precision
If a long outlet tube is used to extend the mixing path, then mixing quality improves, but device weight increases
Solution Approach 1:
The outlet tube is divided into sections with different diameters, allowing optimization of each section's function while minimizing material usage. The first section handles high-flow conditions, while the second section provides extended mixing, reducing the need for a uniformly long and heavy tube
Solution Approach 2:
The outlet tube diameter is changed along its length, transitioning from a larger diameter at the substrate outlet to a smaller diameter in the downstream section. This parameter change increases gas velocity and mixing efficiency in the second section, achieving better mixing with less material
3Measurement precision
If the outlet tube extends deeply into the second sub volume, then mixing path increases, but device complexity increases
Solution Approach 1:
The outlet tube is segmented into two functional sections with a clear transition point, simplifying the design compared to a uniformly complex structure. Each section has a defined purpose: the first section for gas collection and the second section for extended mixing
Solution Approach 2:
The baffle plate is positioned at a specific location within the outlet tube to create three-dimensional flow patterns. This allows the relatively simple outlet tube structure to achieve complex mixing effects through the addition of a single geometric element
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 improves the accuracy of NOx sensor readings by ensuring representative gas mixing, reduces system complexity and weight, and enhances mechanical robustness, allowing for efficient and cost-effective production of compact exhaust treatment devices.
Implementation Method 1
a baffle plate that induces turbulence and mixing, optimizing the flow path
Implementation Method 2
a selective catalytic substrate arranged within the housing, having an outlet face with surface area (A) and dividing the inner volume in a first sub volume near the inlet and second sub volume near the outlet
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An exhaust gas treatment device (1), comprising: - a housing (2) defining a flow path for exhaust gas from the inlet (24) to the outlet (25); - at least one selective catalytic substrate (4) arranged within the housing (2), having an outlet face (41) with surface area "A" and dividing the inner volume in a first sub volume near the inlet and second sub volume near the outlet (25); - the outlet (25) being at least partially defined by an outlet tube (3); - the outlet tube (3) extending through an outer wall of the housing (2) and having an internal portion (38) extending into the second sub volume and an external portion (39) extending away from the housing (2); and - a baffle plate (6) arranged within the second sub volume; - wherein the outlet tube (3) is fixed to the baffle plate (6) at or near a first axial end (32) of the outlet tube (3); - a sensor device (5) arranged along the external portion (39) of the outlet tube (3); wherein the baffle plate (6) comprises a first set of baffle plate openings (61) in an area of the baffle plate (6) outside of the first axial end (32) of the outlet tube (3); and wherein a sidewall of the internal portion (38) of the outlet tube (3) comprises a second set of outlet tube openings (35).