Exhaust Gas Purifier N-Shape Layout for Compact SCR System
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Solution Overview
Problem
The existing SCR-type exhaust gas purification apparatus faces challenges in miniaturization due to the need for a long pipe to evenly diffuse the liquid reducing agent, restricting the layout and preventing space-saving in the length direction of the exhaust gas flow.
Innovation Solution
The apparatus features a communicating pipe with an elbow portion near the first housing and a straight-line portion connecting to the second housing, with the pipe's axis inclined relative to the housings, forming an N-shaped flow passage and allowing for a compact layout by eliminating the need for a pipe that crosses the chassis frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pipe is made long to evenly diffuse the liquid reducing agent, then the diffusion effectiveness is improved, but the length direction size of the exhaust gas purification apparatus increases
Solution Approach 1:
The patent changes the spatial arrangement from a linear sequence to a parallel configuration of first and second housings connected by a communicating pipe. The pipe extends in a direction inclined relative to the axis lines of the housings, utilizing three-dimensional space to achieve both sufficient pipe length for diffusion and compact overall dimensions.
Solution Approach 2:
The exhaust gas purification apparatus is divided into separate functional modules: a first housing containing a filter for collecting particulate matter, and a second housing containing a reducing catalytic converter. These segmented housings are closely disposed in parallel, allowing the communicating pipe to connect them while maintaining compact spacing.
2Reliability
If the pipe transverse the chassis frame to achieve sufficient length, then the diffusion is improved, but the layout flexibility is reduced and miniaturization is hindered
Solution Approach 1:
Instead of having the pipe traverse the chassis frame in a transverse direction, the patent positions the first and second housings in parallel with the communicating pipe extending in an inclined direction relative to the housing axes. This dimensional reconfiguration achieves sufficient pipe length without requiring the pipe to cross the chassis frame, thereby maintaining layout flexibility and enabling miniaturization.
3Length of stationary object
If the first and second housings are closely disposed in parallel, then the overall size is reduced, but the pipe length for diffusion may be insufficient
Solution Approach 1:
The communicating pipe is configured with an inclination relative to the axis lines of the housings, extending in a direction that utilizes the third dimension (vertical or lateral inclination). This allows the pipe to achieve sufficient length for effective diffusion while the housings remain closely disposed in parallel, maintaining compact overall dimensions.
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 secures the necessary pipe length for even diffusion of the liquid reducing agent while reducing the size in the length direction of the exhaust gas flow, achieving a compact size equivalent to a square muffler without imposing conventional layout restrictions.
Implementation Method 1
a filter for collecting a particulate matter in exhaust gas
Implementation Method 2
a reducing catalytic converter for reduction-purifying nitrogen oxide with a liquid reducing agent
Implementation Method 3
a catalytic reduction reaction of NOx in the exhaust gas and the reducing agent to thereby perform a purification treatment of NOx
Implementation Method 4
a nozzle that is disposed in the communicating pipe and injects liquid reducing agent into the exhaust gas
Implementation Method 5
an oxidation catalytic converter for oxidizing nitrogen monoxide in exhaust gas
Implementation Method 6
an oxidation catalytic converter that oxidizes nitrogen monoxide in the exhaust gas to nitrogen dioxide
Implementation Method 7
an ammonia oxidation catalytic converter for oxidizing excess ammonia
Implementation Method 8
an ammonia oxidation catalytic converter that oxidizes ammonia in the exhaust gas
Implementation Method 9
The urea aqueous solution and the ammonia aqueous solution are hydrolyzed with exhaust gas heat and water vapor in the exhaust gas to easily generate ammonia
Data Source
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AI summary
An exhaust gas purification apparatus in which layout restriction is lessened to be able to further achieve space-saving is proposed. The exhaust gas purification apparatus includes a first cylindrical housing in which an oxidation catalytic converter and a PM collection filter are contained and a second cylindrical housing in which a reducing catalytic converter and an ammonia oxidation catalytic converter are contained. The exhaust gas purification apparatus further includes a communicating pipe that connects between far end portions of both the housings, and a nozzle that is disposed in the communicating pipe and injects liquid reducing agent in exhaust gas. The two housings are closely disposed such that axis lines thereof are arranged substantially parallel. The communicating pipe is disposed such that an axis line thereof is arranged substantially parallel with the axis lines of the housings. A flow passage of the exhaust gas from the first housing through the communicating pipe to the second housing is formed into a substantial N-shape.