SCR Catalyst Control Logic Correction via Discretized Input Variables

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Solution Overview

Problem

Conventional methods for determining the amount of reducing agent for selective catalytic reduction (SCR) catalysts in exhaust systems are cumbersome and prone to errors due to rapid changes in driving conditions, leading to performance deterioration and customer complaints from ammonia slip.

Innovation Solution

A method that discretizes and standardizes input variables such as temperature and exhaust flow rate to correct the control logic of the SCR catalyst only when within a predetermined range, ensuring accurate and efficient reducing agent injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the control logic is corrected frequently based on rapid changes in driving conditions, then the accuracy of reducing agent injection is improved, but the SCR catalyst performance deteriorates due to frequent corrections

Engineering Contradiction:

Improveaccuracy of reducing agent injectionVSAvoidSCR catalyst performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The control logic is corrected in advance during periods of stable driving conditions before actual performance issues occur. By performing corrections preliminarily when conditions are favorable (stable temperature and flow rate), the system avoids the need for frequent corrections during transient conditions, thus maintaining SCR catalyst performance while ensuring accurate reducing agent injection.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the control logic is corrected continuously to adapt to changing driving conditions, then the adaptability is improved, but the system stability deteriorates due to frequent corrections

Engineering Contradiction:

Improveadaptability to driving conditionsVSAvoidcontrol logic stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts its correction behavior based on the stability of driving conditions. During stable conditions, corrections are performed to improve adaptability. During transient conditions, corrections are suppressed to maintain stability. This dynamic approach allows the system to balance adaptability and stability according to real-time operating conditions.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If corrections are performed under all driving conditions, then the coverage of correction scenarios is improved, but the correction accuracy deteriorates due to transient characteristics

Engineering Contradiction:

Improvecoverage of correction scenariosVSAvoidcorrection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system applies different correction strategies to different driving condition regions. Stable driving conditions are identified as suitable for corrections, while transient conditions are excluded. This local differentiation ensures that corrections are only performed where they will be accurate and effective, rather than uniformly applying corrections across all conditions.

Inventive Principle:

Principle #3Local quality

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 prevents frequent and inaccurate corrections, enhancing the robustness of the control logic and maintaining the performance of the SCR catalyst by reflecting transient characteristics and ensuring precise reducing agent injection.

Implementation Method 1

A selective catalytic reduction (SCR) catalyst is one type of such a catalytic converter. Reducing agent such as urea, ammonia, carbon monoxide and hydrocarbon (HC) reacts better with nitrogen oxide than with oxygen in the SCR catalyst.

Methodology Applied

Scientific EffectSelective catalytic reduction: Catalysis

Data Source

PatentUS10139842B2Method of correcting control logic of selective catalytic reduction catalyst and exhaust system using the same

Publication Date: 2018.11.27 KIA CORPORATION

AI summary

Disclosed are a method of correcting a control logic of a selective catalytic reduction (SCR) catalyst and an exhaust system. The control logic may be adapted to calculate an injection amount of a reducing agent for the SCR catalyst at the least. The method may include detecting input variables including temperature of the SCR catalyst and exhaust flow rate, discretizing the input variables, standardizing the discretized input variables, determining whether the discretized input variables are within a correction range, and correcting the control logic of the SCR catalyst if the discretized input variables are within the correction range.