Diesel Exhaust Fluid Injector Shield for Crevice Elimination
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Solution Overview
Problem
Diesel exhaust fluid injectors in internal combustion engine aftertreatment systems face challenges with liquid diesel exhaust fluid (DEF) dripping or collecting in crevices between the injector and the side wall, leading to potential solid deposits that interfere with system operation and hinder DEF evaporation.
Innovation Solution
A shield is designed to be mounted horizontally in the side wall of the exhaust gas aftertreatment system, featuring axially and radially extending portions that surround and partially cover the injector face, creating a seal and directing DEF away from the injector and side wall to promote evaporation, while minimizing crevice formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the injector is mounted horizontally in the side wall, then DEF can be injected into the exhaust stream, but liquid DEF collects in crevices between the injector and side wall causing solid deposits
Solution Approach 1:
The patent extracts the problematic crevice space between the injector and side wall by introducing a shield that eliminates the gap where DEF liquid would otherwise collect and form solid deposits, thereby removing the source of reliability issues
Solution Approach 2:
The shield acts as an intermediary component between the injector and side wall, preventing direct contact and crevice formation while maintaining the horizontal mounting configuration that enables DEF injection into the exhaust stream
2Ease of operation
If the injector is mounted horizontally in the side wall, then DEF can be injected into the exhaust stream, but thermal insulation gaps are created
Solution Approach 1:
The shield removes the thermal insulation gap created by horizontal injector mounting by filling the space between the injector body and side wall, preventing thermal energy loss while preserving the injection function
Solution Approach 2:
The shield serves as a thermal bridge and intermediary structure that eliminates insulation gaps, ensuring proper thermal management of the DEF injection system while allowing horizontal mounting for effective exhaust stream injection
3Reliability
If the shield covers the injector face, then DEF collection is prevented, but the shield structure becomes more complex
Solution Approach 1:
The shield is segmented into functional portions: a main body that covers the injector face to prevent DEF collection, and specific features like the annular groove and sealing lip that address particular problems. This segmentation allows the complex functionality to be achieved through modular design elements
Solution Approach 2:
The shield implements local quality by providing different features at different locations: the annular groove at the outer periphery for sealing and the extended lip for preventing liquid accumulation, while keeping the central injection area open. This localized approach achieves reliable DEF evaporation without unnecessary overall 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
The shield effectively prevents DEF from collecting and crystallizing, reduces thermal insulation gaps, and enhances DEF evaporation by directing it into the exhaust stream, thus maintaining system efficiency and preventing operational interference.
Implementation Method 1
enhances DEF evaporation by directing it into the exhaust stream
Data Source
AI summary
A shield for a diesel exhaust fluid injector is mounted horizontally in an opening in a side wall of an exhaust gas aftertreatment system of an internal combustion engine. The diesel exhaust fluid injector configured to inject diesel exhaust fluid in a direction generally normal to the side wall into a mixer positioned in an exhaust gas stream. The shield may include a first portion extending axially and a second portion extending radially inwardly from the first portion.