Urea Mixing Pipe Support for SCR Case Vibration
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Solution Overview
Problem
The existing engine devices face issues with the durability and quakeproofing of urea water injection systems due to engine oscillation, leading to potential damage and improper NOx measurement by NOx sensors, which are not compactly installed in cylindrical SCR cases.
Innovation Solution
The engine device features a urea mixing pipe with a support system that connects the SCR case to the urea mixing pipe, providing improved rigidity and quakeproofing, and a tapered taper portion for NOx sensor installation, allowing for proper NOx measurement and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the urea water injection portion is installed in the exhaust gas connection pipe, then the attaching structure is simplified, but the urea water injection portion is damaged by engine oscillation
Solution Approach 1:
The exhaust gas connection pipe is divided into an upper pipe and a lower pipe that are detachably connected. The urea water injection portion is installed on the lower pipe, which can be separately removed and replaced without affecting the upper pipe or the SCR case, thus simplifying the attaching structure while protecting the injection portion from oscillation damage through easy maintenance.
Solution Approach 2:
The detachable connection between upper and lower pipes allows the system to adapt to oscillation conditions by enabling periodic replacement and repositioning of the lower pipe with the urea water injection portion, maintaining reliability while keeping the overall structure simple.
2Device complexity
If the urea water supply hose is supported to the main machine side, then the attaching structure is simplified, but the hose falls down or is disconnected due to engine oscillation
Solution Approach 1:
The urea water supply hose connection is merged with the detachable pipe connection system. The hose is connected to the lower pipe at the same location where the upper and lower pipes connect, so that when the pipes are reconnected, the hose connection is automatically restored, simplifying the attaching structure while preventing disconnection due to oscillation.
Solution Approach 2:
The lower pipe acts as an intermediary between the main machine side and the SCR case. By connecting the urea water supply hose to the lower pipe rather than directly to the main machine, the system benefits from the lower pipe's positioning and support, reducing the impact of engine oscillation while maintaining a simple attaching structure.
3Measurement precision
If the NOx sensor protrudes out of the SCR case, then the sensor can detect exhaust gas, but the SCR case cannot be compactly installed
Solution Approach 1:
The NOx sensor is nested within the SCR case structure. The sensor is installed in a recess or cavity formed in the SCR case outlet, allowing the sensing element to protrude into the exhaust gas flow path for detection while the sensor body remains contained within the SCR case volume, achieving both detection capability and compact installation.
Solution Approach 2:
The NOx sensor is positioned to detect exhaust gas in the radial direction rather than protruding axially from the SCR case. By orienting the sensor perpendicular to the main exhaust flow direction and installing it on the outlet surface, the sensor achieves effective detection without increasing the axial length of the SCR case, thus maintaining compactness.
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 enhances the durability and quakeproofing of the urea water injection system, reduces mechanical oscillation, and enables precise NOx measurement while maintaining a compact SCR case design, improving the overall exhaust gas purification efficiency.
Implementation Method 1
a urea water injection means is arranged in the exhaust gas inlet side of the urea mixing pipe
Implementation Method 2
an SCR case which removes nitrogen oxides in the exhaust gas of the engine
Implementation Method 3
the exhaust gas inlet side of the urea mixing pipe is supported to the exhaust gas outlet side of the SCR case... it is possible to suppress mechanical oscillation
Data Source
AI summary
In an engine device having a urea mixing pipe which injects urea water into exhaust gas of an engine, and an SCR case which removes nitrogen oxides in the exhaust gas of the engine, and structured such that an inlet side of the SCR case is connected to an outlet side of the urea mixing pipe, an exhaust gas outlet side of the SCR case is connected to an exhaust gas inlet side of the urea mixing pipe where a urea water injection means is arranged, and an exhaust gas inlet side of the urea mixing pipe is supported to the exhaust gas outlet side of the SCR case.