Threaded Flow Channel Heated Injection Nozzle for SCR Cold Start
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Solution Overview
Problem
Existing injection nozzles for selective catalytic reduction in internal combustion engines are inefficient at low temperatures during cold starts, as they require complex heating structures that consume space and do not adequately enhance the effectiveness of nitrogen oxide reduction.
Innovation Solution
The injection nozzle features a flow channel formed by a thread around the inner body, with sections of different thread pitches, allowing for increased residence time and heating of the reducing agent, which evaporates and expands, improving the distribution and effectiveness of the reducing agent in the exhaust gas stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heating mechanism is added to the injection nozzle to improve reducing agent evaporation at low temperatures, then the effectiveness of selective catalytic reduction during cold start is improved, but the device complexity and installation space requirements increase
Solution Approach 1:
The heating element is integrated directly into the injection nozzle structure, merging the heating function with the existing nozzle components. This combination eliminates the need for separate heating devices and reduces overall system complexity while maintaining effective heating capability for improving SCR performance during cold start.
Solution Approach 2:
The injection nozzle is designed to serve multiple functions: it delivers the reducing agent, heats it to enable evaporation, and injects it into the exhaust stream. This multi-functionality is achieved by incorporating the heating element within the nozzle structure, allowing a single component to perform what would traditionally require multiple separate devices.
2Reliability
If the flow channel is extended to increase residence time for heating, then the evaporation completeness of reducing agent is improved, but the nozzle length and installation space increase
Solution Approach 1:
The flow channel incorporates helical or spiral sections instead of straight linear paths. This curved geometry increases the flow path length and residence time within a compact nozzle body, allowing complete evaporation of the reducing agent without significantly increasing the overall nozzle length or installation space requirements.
Solution Approach 2:
The flow channel utilizes three-dimensional spatial arrangement with helical paths that wrap around the nozzle axis. This dimensional approach allows the flow to traverse a longer path through the heating zone without extending the nozzle's axial length, effectively packing more heating path into a compact volume.
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 design enhances the catalytic reduction of nitrogen oxides at low temperatures by ensuring complete evaporation and fine distribution of the reducing agent, improving the SCR catalytic converter's performance during cold starts and reducing nitrogen oxide emissions.
Implementation Method 1
the injection nozzle has at least one heating element
Implementation Method 2
the reducing agent, which evaporates and expands
Implementation Method 3
the flow channel is formed at least partially by a thread, in particular a single-start or multi-start thread, around the inner body from the reducing agent inlet to the nozzle head
Implementation Method 4
In the exhaust gas, the urea decomposes into gaseous ammonia and CO2 at temperatures above 150° Celsius
Data Source
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AI summary
An injection nozzle (100) for injecting a reducing agent into the exhaust gas stream of an internal combustion engine for selective catalytic reduction, wherein the injection nozzle (100) comprises an outer nozzle jacket (110), an inner body (160) arranged in the nozzle jacket (110), and a nozzle head (130) with at least one outlet opening (140), wherein the nozzle jacket (110) has a reducing agent inlet (120) and at least one flow channel (150) extending from the reducing agent inlet (120) to the nozzle head (130) is formed between the nozzle jacket (110) and the inner body (160), wherein the inner body (160) has at least one heating element or is designed as a heating element, wherein the flow channel (150) is at least partially threaded, in particular by a single-start or multi-start thread, around the inner body (110) from the reducing agent inlet (120) to the nozzle head. (130) is formed.