SCR Dosing Control via Soot-Based Regeneration Coordination

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Solution Overview

Problem

Existing exhaust treatment systems for vehicles and platforms do not always provide optimal treatment and diagnostics, particularly under varying soot conditions, which affects the efficiency of NOx reduction and SCR catalyst health monitoring.

Innovation Solution

A method and system that estimate the amount of soot in exhaust using a processor, adjust urea flow rates, and selectively control NOx reduction and diagnostics for selective catalyst reduction catalysts (SCR) based on soot levels, with ammonia to NOx ratio adjustments and diagnostic enablement/disabling depending on soot thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous diagnostics are performed on SCR catalysts, then diagnostic reliability is improved, but system complexity and computational load increase

Engineering Contradiction:

ImproveSCR health monitoring reliabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The diagnostic system dynamically adjusts its operation based on soot levels. When soot levels are low, continuous diagnostics are enabled to monitor SCR health reliably. When soot levels exceed thresholds, diagnostics are temporarily disabled to reduce complexity and computational load. This dynamic switching resolves the contradiction by adapting diagnostic intensity to actual system conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the diagnostic parameter state based on soot concentration. By monitoring soot levels as a controlling parameter, the system switches between diagnostic modes (enabled/disabled) to balance reliability needs against system complexity. This parameter-based control allows the system to maintain diagnostic reliability when needed while reducing complexity under high-soot conditions.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If urea flow rate is increased to improve NOx reduction, then emission treatment efficiency is improved, but ammonia slip increases when soot levels are high

Engineering Contradiction:

ImproveNOx reduction efficiencyVSAvoidammonia slip

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically adjusts the urea flow rate parameter based on soot level measurements. When soot levels are below thresholds, higher urea flow rates are applied to maximize NOx reduction efficiency. When soot levels exceed thresholds, the urea flow rate is reduced to prevent excessive ammonia slip. This parameter adaptation resolves the contradiction by optimizing urea dosing according to actual exhaust conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system uses feedback from soot level measurements to adjust urea injection rates. The processor continuously monitors soot concentration and uses this information to modulate the urea flow rate, creating a closed-loop control system that balances NOx reduction efficiency against ammonia slip prevention based on real-time exhaust conditions.

Inventive Principle:

Principle #23Feedback

3Productivity

If ammonia to NOx ratio is increased above one, then NOx conversion is improved, but passive regeneration capability is reduced

Engineering Contradiction:

ImproveNOx conversion efficiencyVSAvoidpassive regeneration capability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system dynamically switches between different ammonia to NOx ratio strategies based on soot accumulation levels. During low-soot conditions, the ratio is maintained above one to maximize NOx conversion efficiency. During high-soot conditions, the ratio is adjusted to preserve NO2 availability for passive regeneration of the diesel particulate filter. This dynamic strategy resolution allows the system to alternate between optimization goals based on actual regeneration needs.

Inventive Principle:

Principle #15Dynamics

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

Enhances exhaust treatment efficiency by optimizing NOx reduction and SCR health monitoring, ensuring effective passive and active regeneration strategies based on soot levels, thereby improving overall emission control system performance.

Implementation Method 1

selective catalyst reduction catalysts (SCR)

Methodology Applied

Scientific EffectSelective Catalytic Reduction: Catalysis

Implementation Method 2

reduction of NOx between selective catalyst reduction catalysts (SCR)

Methodology Applied

Scientific EffectChemical reduction: Reduction

Implementation Method 3

diesel particulate filter (DPF)

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 4

diesel oxidation catalysts (DOC)

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12012886B1Dosing control and passive regeneration coordination with diagnostic

Publication Date: 2024.06.18 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

Methods and systems for controlling treatment of exhaust in a emission control system of a platform having a combustion system is provided. In an exemplary embodiment, the method includes estimating, via a processor, an amount of soot in exhaust from the combustion system; and controlling, via the processor, treatment of the exhaust based on the amount of soot in the exhaust.