Honeycomb Structure Sensor Plug-in Hole Deep Hole
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Solution Overview
Problem
Conventional honeycomb structures for catalyst converters in automobiles face challenges in precisely controlling exhaust gas due to limited sampling capabilities and uneven gas flow, which affects engine control and purification performance, especially with fluctuations in excess air ratio (λ) and large sectional areas.
Innovation Solution
A honeycomb structure with a sensor plug-in hole and a deep hole that communicates with it, allowing for uniform gas flow and sampling from areas other than the sensor hole, thereby enabling precise control of the excess air ratio and improved purification performance without compromising isostatic strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hole is formed in the honeycomb structure to insert the sensor, then the sensor can be installed to monitor exhaust gas, but gas can only be sampled from the sensor hole and not from other portions, resulting in uneven gas flow and imprecise exhaust gas control
Solution Approach 1:
The sensor hole is divided into two functional segments: the upper portion serves as the sensor insertion hole, while the lower portion is converted into a deep hole that extends through the partition wall to the other end face. This segmentation allows the deep hole to serve as an additional gas sampling point, enabling gas to be sampled from multiple locations (sensor hole and deep hole) simultaneously, thereby improving both measurement precision and adaptability.
Solution Approach 2:
The deep hole extends in the longitudinal dimension of the honeycomb structure, creating a three-dimensional gas sampling network. By forming the deep hole that reaches the other end face, the system transitions from a single-point (two-dimensional) sampling approach to a multi-point (three-dimensional) sampling approach, allowing exhaust gas to be sampled from both the sensor hole and the deep hole, thus improving gas flow uniformity and control precision.
2Quantity of substance
If the diameter of the honeycomb structure is large, then the catalyst capacity is increased, but the fluctuations of excess air ratio between cylinders become more remarkable, making it difficult to precisely control exhaust gas
Solution Approach 1:
The large honeycomb structure is segmented into multiple sampling zones by creating both the sensor hole and the deep hole. This segmentation allows exhaust gas from different regions (including multiple cylinders) to be sampled and mixed before reaching the sensor, thereby reducing the impact of local fluctuations in excess air ratio and improving overall control precision while maintaining large catalyst capacity.
Solution Approach 2:
The deep hole acts as an intermediary structure that facilitates uniform gas flow distribution. By providing an additional flow path through the partition wall, the deep hole mediates the gas flow from various cylinders, ensuring more uniform mixing and distribution of exhaust gas before it reaches the sensor, thus reducing fluctuations in excess air ratio and improving control precision.
3Device complexity
If a conventional sensor hole is used, then the structure is simple, but the exhaust gas flow into the sensor is uneven and only partial sampling is achieved, preventing precise engine control
Solution Approach 1:
The sensor hole is segmented into functional zones: the upper sensor insertion zone and the lower deep hole zone. This segmentation creates a more sophisticated sampling system that maintains relative structural simplicity while significantly improving sampling accuracy by enabling gas to be drawn from multiple locations through the deep hole extension.
Solution Approach 2:
The deep hole adds a longitudinal dimension to the sampling system, extending from the outer peripheral surface through the partition wall to the other end face. This dimensional extension creates additional sampling pathways without substantially increasing structural complexity, thereby improving sampling accuracy while maintaining design simplicity.
Data Source
AI summary
A precise exhaust gas control can be achieved without being influenced by fluctuations of the excess air ratio (λ) between cylinders of engines or the size of the diameter (the sectional area) of the honeycomb structure. The honeycomb structure is formed by a plurality of cells separated from one another by porous partition walls and functioning as fluid flow paths, the honeycomb structure includes: a sensor plug-in hole 7 which is formed in an outer peripheral surface 4 of the honeycomb structure and into which a sensor can be plugged, and the sensor plug-in hole 7 is provided with at least one deep hole 8 which communicates with the sensor plug-in hole.