Exhaust Additive Injection Control for Residue Prevention
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Solution Overview
Problem
Existing systems for controlling the injection of additives in exhaust streams for reducing nitrogen oxides in combustion engines lack precision, leading to increased back pressure, reduced purification efficiency, and potential residue formation, which can result in non-compliance with emission standards and increased fuel consumption.
Innovation Solution
A method that determines time-dependent conditions based on exhaust and additive mass flows, internal temperatures, and temperature models to precisely control the injection of additives into the exhaust stream, optimizing evaporation efficiency and reducing the risk of residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more additive is injected into the exhaust stream to improve nitrogen oxide reduction, then purification efficiency is improved, but residues/precipitates/crystallisations are formed downstream increasing back pressure and reducing evaporation efficiency
Solution Approach 1:
The system performs preliminary action by determining time-dependent conditions and predicting the risk of critical conditions (residue formation) before they occur. The control system uses temperature models and mass flow data to anticipate potential residue formation and adjusts additive injection accordingly, preventing the harmful effect before it manifests.
Solution Approach 2:
The system implements feedback control by continuously monitoring exhaust mass flow, additive mass flow, and temperature conditions, then using this information to adjust the additive injection rate. The control system adapts the injection strategy based on real-time conditions to maintain optimal purification efficiency while preventing residue formation.
2Productivity
If precise control of additive injection is implemented to prevent residue formation, then back pressure is reduced and evaporation efficiency is improved, but system complexity increases
Solution Approach 1:
The system replaces complex mechanical control mechanisms with computational models and electronic control. Temperature models, mass flow calculations, and risk prediction algorithms substitute for purely mechanical dosing systems, achieving precise control through software-based decision making rather than complex mechanical linkages.
Solution Approach 2:
The system achieves precise control by dynamically changing operational parameters (additive mass flow rate, injection timing) based on calculated risk levels. The control system adjusts these parameters in response to varying exhaust conditions, enabling adaptive control without requiring complex mechanical adjustment mechanisms.
3Reliability
If additive injection is increased to meet stricter emission standards, then nitrogen oxide reduction is improved, but fuel consumption increases due to increased back pressure
Solution Approach 1:
The system implements dynamic control of additive injection, continuously adapting the injection rate to current exhaust conditions rather than using a fixed injection strategy. This dynamic approach allows the system to meet emission standards while minimizing unnecessary additive injection that would increase back pressure and fuel consumption.
Solution Approach 2:
The system applies partial action by injecting only the necessary amount of additive required to meet emission standards under current conditions, rather than using a constant high injection rate. The control system calculates the optimal injection level needed for compliance, avoiding excessive injection that would create residues and increase back pressure.
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 approach allows for precise control of additive injection, improving evaporation efficiency, reducing back pressure, and enhancing the reduction of nitrogen oxides, enabling compliance with stricter emission standards like Euro VI and potentially improving fuel efficiency.
Implementation Method 1
the additive is injected into an evaporation chamber (280) when being injected into the exhaust stream (203), and is there evaporated
Implementation Method 2
at least one time dependent condition Ci of at least one position Pi at an internal wall (281) of the evaporation chamber (280) is determined
Data Source
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AI summary
A method and a system for control of a dosage device and/or an engine are presented. The engine produces an exhaust stream (203) being treated by an exhaust treatment system (250) by use of at least one additive being injected into the exhaust stream (203) by the dosage device (271 ). The additive is evaporated in an evaporation chamber (280) when being injected into the exhaust stream (203). According to the invention, the method includes: - determining a time dependent condition of a position at an internal wall (281 ) of the evaporation chamber (280), the condition being determined based on the internal temperature related to the position, the internal temperature being determined based on a temperature model for the evaporation chamber (280) and an exhaust temperature for the exhaust stream (203) upstream the evaporation chamber (208); - determining a risk for at least one spatially resolved critical condition related to the position based on the time dependent condition and - controlling the dosage device (271 ) and/or the engine based on the determined risk.