Counter-Flow Fluid Dosing Nozzle for Exhaust Mixing
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Solution Overview
Problem
Existing gas flow dosing devices face challenges in achieving efficient mixing of reagents with exhaust gases across varying flow speeds and conditions, often resulting in incomplete mixing due to turbulence issues and material deposits on nozzle components.
Innovation Solution
A fluid dosing device that injects a fluid counter to the gas flow direction, equipped with a valve mechanism to prevent material deposits and an air supply system to create a clean air pocket around the nozzle, ensuring efficient mixing and reducing back-pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spray of reducing agent is perpendicular to the exhaust flow, then mixing is optimized at relatively low exhaust velocities, but when exhaust velocity is increased the spray is deflected resulting in incomplete mixing
Solution Approach 1:
The patent inverts the conventional spray orientation by directing the reducing agent spray substantially counter to the exhaust flow direction rather than perpendicular or downstream. This counter-flow injection creates immediate turbulence and mixing at the injection point, ensuring effective dispersion across a wide range of exhaust velocities without spray deflection issues
2Productivity
If a turbulence generating feature such as a rotating blade is used to create inhomogeneities in the exhaust gas stream, then mixing is improved, but a permanent back-pressure is created within the exhaust system leading to loss of engine efficiency
Solution Approach 1:
The patent removes the separate turbulence-generating component (rotating blade) from the system and instead generates the necessary turbulence directly through the counter-flow injection mechanism itself. The opposing spray direction creates immediate flow disruption and mixing without requiring additional mechanical turbulence devices that would create permanent back-pressure
Solution Approach 2:
The patent merges the injection function and turbulence generation function into a single mechanism. The counter-flow spray injection simultaneously delivers the reducing agent and creates the turbulence needed for mixing, eliminating the need for separate turbulence-generating components and their associated energy losses
3Device complexity
If the nozzle is exposed to the exhaust flow, then the device structure is simplified, but material deposits form on the nozzle components
Solution Approach 1:
The patent implements a valve mechanism that closes the nozzle opening before the exhaust flow can cause material deposits to form. The valve is actuated to seal the nozzle in a closed position during periods when injection is not required, preventing exposure to the exhaust environment and subsequent clogging, while allowing full exposure and injection capability when needed
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 device achieves enhanced mixing of the fluid and gases, maintaining efficiency across different flow conditions while minimizing the risk of material deposits and energy loss.
Implementation Method 1
valve means arranged to move between a first position in which the valve means seals the nozzle means and a second open position in which injection of fluid into the gas flow can take place
Implementation Method 2
the fluid dosing device is arranged to inject fluid into the gas flow in a direction which is substantially counter to the flow direction of the gas flow
Implementation Method 3
For maximum efficiency in the reduction reaction it is important that the reducing agent is dispersed evenly throughout the exhaust flow
Implementation Method 4
air supply means arranged to supply air from a source of air to the nozzle means
Data Source
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AI summary
A fluid dosing device (57) for introducing a fluid into a gas flow having a given flow direction, the dosing device comprising: input means (66) for receiving the fluid from a source of fluid; nozzle means (62) for injecting the fluid into the gas flow, the nozzle means comprising valve means (132) arranged to move between a first position in which the valve means seals the nozzle means and a second open position in which injection of fluid into the gas flow can take place wherein the fluid dosing device is arranged to inject fluid into the gas flow in a direction having at least a component which is counter to the flow direction of the gas flow.