Reducing Agent Injection Control via Dynamic Model
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Solution Overview
Problem
Current methods for controlling the injection of reducing agents in exhaust systems upstream of catalysts in combustion engines are inefficient, leading to excessive consumption and environmental discharge of reductive substances like ammonia, and require extensive empirical charting and testing for each engine-catalyst combination, which is not adaptable to dynamic operating conditions.
Innovation Solution
A method that approximates the influence of reducing agent injection as a first-order process with an amplification factor and time constant, using a computation model to determine instantaneous values of these parameters, allowing for robust regulation and reduced catalyst volume usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-dimensional charts based on steady-state performance are used to control reducing agent injection, then dosage values can be determined for specific engine load and speed conditions, but the system cannot adapt to dynamic operating conditions and requires extensive empirical testing for each engine-catalyst combination
Solution Approach 1:
The patent transitions from static two-dimensional charts to a dynamic computation model that continuously calculates optimal reducing agent dosage based on real-time engine operating parameters. The model dynamically adjusts dosage recommendations as engine load, speed, and other parameters change, enabling adaptation to transient operating conditions rather than relying on pre-determined steady-state values.
Solution Approach 2:
The computation model incorporates multiple engine parameters (load, speed, temperature, etc.) as dynamic inputs that continuously change during operation. By monitoring and responding to parameter changes in real-time, the system adjusts reducing agent dosage recommendations to match current operating conditions, eliminating the need for extensive empirical charting for each specific engine-catalyst combination.
2Measurement precision
If comprehensive test runs and settings are performed for each specific engine-catalyst combination, then accurate dosage values can be obtained, but the process becomes troublesome and time-consuming
Solution Approach 1:
The patent uses a computation model that virtualizes the complex empirical testing process. Instead of performing physical test runs for each engine-catalyst combination, the model creates a virtual representation that calculates optimal dosage based on theoretical relationships between engine parameters and catalytic conversion efficiency, dramatically reducing setup time while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical process of extensive empirical testing and chart compilation with a computational approach. The computation model uses mathematical relationships and engine parameters to directly calculate optimal dosage, substituting time-consuming physical testing and manual chart creation with automated computational analysis.
3Reliability
If larger amounts of reducing agent are injected to ensure sufficient conversion, then catalytic conversion efficiency is maintained, but excessive reductive substance is discharged to the environment causing pollution and waste
Solution Approach 1:
The computation model incorporates feedback mechanisms that continuously monitor engine operating conditions and catalytic conversion requirements. By using real-time parameter feedback, the system calculates the precise reducing agent dosage needed to maintain optimal conversion efficiency, preventing both under-dosage (which would reduce effectiveness) and over-dosage (which would cause environmental discharge).
Solution Approach 2:
The system dynamically adjusts reducing agent dosage based on changing engine parameters and catalytic converter state. By responding to parameter changes in real-time, the system maintains conversion efficiency across varying operating conditions without applying excessive reducing agent, thereby minimizing environmental discharge while ensuring reliable NOx conversion.
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 enables rapid and effective regulation of reducing agent injection, minimizing consumption and environmental impact while maintaining efficient catalytic conversion, and is adaptable to various engine-catalyst configurations without the need for extensive empirical testing.
Implementation Method 1
A reductive substance which forms part of, or is formed by, the reducing agent is carried by the exhaust gases into the catalyst, in which it is adsorbed on active seats in the catalyst, resulting in accumulation of the reductive substance in the catalyst
Implementation Method 2
The accumulated reductive substance may either be desorbed, i.e. released from the active seats, or react with and thereby convert an exhaust substance to a non-hazardous substance
Implementation Method 3
An SCR catalyst selectively reduces NO x in the exhaust gases but not the sulphur in the exhaust gases. The ammonia accumulates in the catalyst by being adsorbed on active seats in the catalyst, and NO x present in the exhaust gases is converted to nitrogen and water when it is brought into contact in the catalyst with accumulated ammonia on the active seats in the catalyst
Data Source
Figure 1
Figure 2~4
AI summary
A method for determination of regulating parameters of a regulator (13) which forms part of a system for controlling the injection of reducing agent upstream of a catalyst in an exhaust line from a combustion engine and which, on the basis of a signal which is delivered by a comparator (12) and depends on the match between an actual value and a set-point value of a variable related to function of the catalyst and affected by the reducing agent injection, generates a control signal which acts upon the injection of reducing agent. The influence of the reducing agent injection on said variable is approximated as a first-order process with an amplification factor and a time constant. Instantaneous values of this amplification factor and time constant are determined on the basis of information from a computation model which continuously determines current states in the catalyst. Instantaneous values of regulating parameters of the regulator are determined on the basis of the thus determined values of said amplification factor and time constant. The invention relates also to a system of said type in which regulating parameters of the system's regulator are determined in this way.