Engine Exhaust Apparatus Flow Rectifier Design
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Solution Overview
Problem
The existing exhaust apparatus for engines suffers from inefficient exhaust heat recovery due to uneven flow of exhaust gas into the exhaust heat recovery unit, leading to reduced recovery efficiency.
Innovation Solution
Incorporating a flow rectifier and a radially contracting exhaust passage design that gradually reduces in diameter towards the exhaust heat recovery unit, ensuring uniform gas flow and enhanced heat recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the upstream side of the exhaust passage is configured to increase in diameter toward the exhaust heat recovery unit, then the exhaust passage structure is simplified, but the exhaust gas flows unevenly and concentrates in the central portion, deteriorating the exhaust heat recovery efficiency
Solution Approach 1:
The exhaust passage is divided into multiple sections with different diameter characteristics: a first radially contracting portion upstream of the flow rectifier, a substantially constant diameter portion through the flow rectifier, and a second radially contracting portion downstream. This segmentation allows each section to perform its specific function - the first contracting portion directs flow toward the center for rectification, the constant diameter portion maintains uniform flow through the rectifier, and the second contracting portion distributes flow evenly into the heat recovery unit, thereby resolving the contradiction between structural simplicity and flow uniformity.
Solution Approach 2:
Different sections of the exhaust passage are given different local geometric qualities - the first portion has a contracting diameter to guide flow, the middle portion has constant diameter for uniform flow maintenance, and the second portion has contracting diameter for even distribution. This local differentiation of geometric properties allows the passage to achieve both structural simplicity and optimal flow characteristics for heat recovery efficiency.
2Productivity
If a flow rectifier is added to rectify the exhaust gas flow, then the exhaust heat recovery efficiency is improved, but the device complexity increases
Solution Approach 1:
The flow rectifier is integrated with the exhaust passage itself rather than being a separate component. The rectifying function is achieved through the geometric design of the passage - specifically the first radially contracting portion and the substantially constant diameter portion that together create the rectifying effect. This merging of the rectifier function into the passage structure achieves flow rectification without adding separate components, thus improving heat recovery efficiency while minimizing device complexity.
Solution Approach 2:
The exhaust passage serves multiple functions: it transports exhaust gas, rectifies flow through its geometric design (first contracting portion and constant diameter portion), and prepares uniform flow distribution to the heat recovery unit. By making the passage itself multi-functional, the need for separate rectifier components is eliminated, resolving the contradiction between improved rectification and increased complexity.
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 exhaust heat recovery efficiency by ensuring uniform gas flow and effective heat extraction from the outer peripheral area of the heat recovery unit, simplifying the apparatus structure and enhancing the rectifying effect of the catalytic converters.
Implementation Method 1
a cooling portion for cooling the exhaust heat recovery portion from the outer peripheral side thereof through cooling fluid
Data Source
AI summary
An engine exhaust apparatus includes an exhaust passage for flowing exhaust gas emitted from an engine, a flow rectifier for rectifying the flow of the exhaust gas, and an exhaust heat recovery unit disposed in the exhaust passage downstream of the flow rectifier. The exhaust heat recovery unit is provided with an exhaust heat recovery portion and a cooling portion to cool the exhaust heat recovery portion. The engine exhaust apparatus further includes a first diameter reducing portion gradually reduced in diameter toward the exhaust heat recovery unit from the flow rectifier, and a second diameter reducing portion gradually reduced in diameter toward the downstream from the exhaust heat recovery unit.