Outward-Opening Injection Valve for Exhaust Aftertreatment
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Solution Overview
Problem
Existing injection devices for exhaust-gas aftertreatment systems struggle to achieve a fine spray distribution and protect the valve seat from contamination by soot particles and high temperatures, which affects the longevity and efficiency of NOx reduction in internal combustion engines.
Innovation Solution
A pressure-controlled, outward-opening injection valve with a perforated injection plate and a valve piston that interacts with a valve seat, featuring a thread-like groove and axial stop, generates a fine spray by accelerating the exhaust-gas aftertreatment agent through a narrow annular flow channel and protects the valve seat from contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inner-opening injection valve is used, then the spray can be generated, but the valve seat is exposed to soot particles and high temperatures causing contamination and reduced service life
Solution Approach 1:
The patent inverts the conventional valve opening direction from inner-opening to outer-opening. The valve piston moves in reverse direction relative to traditional designs, with the valve tip opening outward away from the valve seat. This inversion protects the valve seat from direct exposure to soot particles and high temperatures in the exhaust gas, preventing contamination while maintaining injection function
Solution Approach 2:
The patent introduces a protective structure acting as an intermediary between the valve seat and the harmful exhaust environment. This intermediary barrier shields the valve seat from direct contact with soot particles and high temperatures, allowing the valve mechanism to function reliably without direct exposure to contaminants
2Productivity
If the spray is made finer for better NOx reduction, then the mixing effectiveness improves, but the valve seat becomes more vulnerable to contamination
Solution Approach 1:
By inverting the valve opening direction to outer-opening, the patent enables fine spray generation through precise valve tip control while simultaneously protecting the valve seat from contaminants. The outward opening direction allows the fine spray to be generated away from the vulnerable valve seat area
3Manufacturing precision
If high injection pressures are achieved for fine spray, then the spray quality improves, but the valve mechanism becomes more complex
Solution Approach 1:
The patent achieves high injection pressures and fine spray quality by optimizing geometric parameters of the valve tip and flow channel rather than adding complex mechanisms. Parameter optimization of the valve tip geometry and flow channel dimensions enables precise control of spray characteristics while maintaining a relatively simple valve structure
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 solution ensures a long service life of the injection device by producing a fine spray for effective NOx reduction, preventing valve seat contamination, and maintaining high injection pressures while protecting the valve seat from soot particles and high temperatures.
Implementation Method 1
at least one spring element which urges the valve piston comprising the valve tip against the valve seat in order to close the throughflow opening
Implementation Method 2
pressure-controlled and outward-opening injection valve which comprises an axially displaceable valve piston... generates a fine spray by accelerating the exhaust-gas aftertreatment agent through a narrow annular flow channel
Data Source
AI summary
The invention relates to an injection device (1), in particular for an exhaust aftertreatment system of an internal combustion engine, comprising a pressure-controlled, outward-opening fuel injection valve (2) that includes an axially movable valve piston (6) which penetrates a flow opening (7) in a valve body (5) and one end of which has a valve tip (9), further comprising a valve seat (8) associated with the flow opening (7), and at least one spring element (11) which urges the valve piston (6) comprising the valve tip (9) against the valve seat (8) so that the flow opening (7) is closed; the valve tip (9) is axially movable inside a flow chamber (15) formed by the valve body (5) and by an injection orifice disk (14) that includes a plurality of injection ports (19).