Upstream Pipe Expanded Portion for Diesel Particulate Filter Pressure Sensing
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Solution Overview
Problem
Existing exhaust gas control apparatuses for diesel engines face clogging issues in pressure introduction pipes due to particulate matter (PM), soot, and soluble organic fractions (SOF), which complicates the structure and increases production costs, and makes it difficult to accurately determine the timing for particulate filter recovery.
Innovation Solution
The apparatus includes an upstream pipe with an expanded portion near the particulate filter, having a greater inner diameter than the rest, which minimizes PM deposition and clogging, and features a bent portion to further reduce PM entry into the pressure detection area, eliminating the need for complex structures like pulsation-absorbing chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure difference sensor is used to detect PM deposition on the particulate filter, then the timing for filter recovery can be determined, but the pressure introduction pipe becomes clogged by PM, soot, and SOF
Solution Approach 1:
The pressure introduction pipe is divided into two sections: a first pressure introduction pipe with a larger diameter that is less prone to clogging, and a second pressure introduction pipe with a smaller diameter that connects to the sensor. This segmentation allows the system to maintain both accurate measurement capability and reliable pipe functionality.
Solution Approach 2:
Different sections of the pressure introduction system are given different properties - the first pipe section has a larger diameter for resistance to clogging, while the second pipe section has a smaller diameter optimized for sensor connection. This local differentiation of properties resolves the contradiction between measurement precision and pipe reliability.
2Reliability
If pulsation-absorbing chambers or complex pipe insertion structures are used to prevent pipe clogging, then PM deposition is reduced, but the device complexity and production cost increase
Solution Approach 1:
Instead of using complex pulsation-absorbing chambers, the invention segments the pressure introduction pipe into two simple cylindrical sections with different diameters. This segmentation achieves the anti-clogging function without requiring complex structures, thereby maintaining device simplicity and low production cost while ensuring pipe reliability.
3Reliability
If the inner diameter of the pressure introduction pipe is increased to reduce PM deposition, then clogging is minimized, but the pipe volume and device complexity increase
Solution Approach 1:
The pressure introduction system is segmented into two pipe sections with different diameters. The first section has a larger diameter to prevent clogging, while the second section has a smaller diameter to minimize overall volume. This segmented approach achieves both anti-clogging reliability and compact size.
Solution Approach 2:
Different diameter properties are applied locally to different sections of the pressure introduction system. The larger diameter is applied only where needed for clogging prevention, while the smaller diameter is used where volume minimization is prioritized. This local differentiation resolves the contradiction between reliability and volume.
Data Source
AI summary
An exhaust gas control apparatus that includes a pressure difference sensor that detects the difference in pressure between the upstream side and the downstream side of a particulate filter (DPNR catalyst), which captures particulate matter that is present in exhaust gas. In the exhaust gas control apparatus, the pipes that introduce the pressure to the pressure difference sensor include an upstream pipe that introduces the pressure on the upstream side of the particulate filter to the pressure difference sensor. The upstream pipe includes an expanded pipe portion, which has an inner diameter greater than that of the portion of the upstream pipe near the pressure difference sensor, near the particulate filter. With this configuration, the deposition of particulate matter, soot, soluble organic fractions, and the like in the upstream pipe is suppressed, which minimizes clogging of the upstream pipe.