Adaptive Reductant Dosing for SCR Emission Control

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Solution Overview

Problem

Diesel engines face challenges in efficiently reducing nitrogen oxides (NOx) emissions due to the inefficiency of two-way catalytic converters, necessitating the use of reductant-based selective catalytic reduction (SCR) systems, which require optimal reductant dosing strategies to meet emission standards while considering reductant availability and refill distances.

Innovation Solution

A controller system that determines available reductant levels and distance to a refill station, adjusting reductant dosing accordingly, and integrates with in-cylinder emission control methods to optimize NOx reduction, employing a method that includes monitoring reductant consumption and adjusting dosing protocols to maintain emission standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If reductant dosing is increased to reduce NOx emissions, then emission compliance is improved, but reductant consumption increases

Engineering Contradiction:

ImproveNOx emissionsVSAvoidreductant consumption

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts reductant dosing based on real-time conditions including distance to refill stations, current reductant levels, and predicted travel distance. The controller modifies dosing rates adaptively rather than using fixed dosing strategies, allowing optimization between emission control and reductant conservation based on operational context

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes dosing parameters (reductant injection rate) based on varying operational parameters such as distance to refill station, current reductant inventory, vehicle speed, and load conditions. This allows the system to maintain effective NOx control while conserving reductant when full dosing is not necessary or sustainable

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If reductant dosing is decreased to conserve reductant, then reductant consumption is reduced, but NOx emissions increase

Engineering Contradiction:

Improvereductant conservationVSAvoidNOx emissions

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary assessment of reductant sufficiency by calculating distance to refill stations and predicting whether current reductant levels will be adequate for the remaining journey. Based on this advance knowledge, the system proactively adjusts dosing strategies to either conserve reductant when sufficient or increase dosing when approaching emission limits

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors reductant consumption rates, current tank levels, and actual emission outcomes, using this feedback to adjust dosing strategies in real-time. The controller learns from past performance and adapts dosing rates to maintain emission compliance while optimizing reductant usage patterns

Inventive Principle:

Principle #23Feedback

3Quantity of substance

If adaptive dosing strategy is implemented to optimize reductant usage, then reductant efficiency is improved, but system complexity increases

Engineering Contradiction:

Improvereductant efficiencyVSAvoidcontrol system complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The control system integrates multiple functions into a single adaptive dosing controller that handles reductant level monitoring, distance calculation, dosing rate optimization, and emission compliance verification. This multi-functional approach consolidates complexity rather than distributing it across separate systems

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system performs self-assessment of reductant sufficiency by using onboard sensors and navigation data to calculate whether current reductant levels will sustain the vehicle to the next refill station. This self-service capability eliminates the need for external monitoring systems while maintaining sophisticated dosing optimization

Inventive Principle:

Principle #25Self-service

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 system effectively reduces NOx emissions by optimizing reductant usage, ensuring compliance with emission standards while minimizing fuel consumption and vehicle performance impact, thereby enhancing the overall efficiency of the SCR system.

Implementation Method 1

a reductant-based selective catalytic reduction (SCR) device in order to seek reduction in nitrogen oxide concentrations

Methodology Applied

Scientific EffectSelective catalytic reduction: Catalysis

Implementation Method 2

reductant-based selective catalytic reduction (SCR) device... reduce nitrogen oxide concentrations

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS7991533B2Adaptive reductant dosing and emission control strategies

Publication Date: 2011.08.02 SOUTHWEST RES INST

AI summary

The present disclosure relates to a method or apparatus for controlling reductant dosing level introduced to a selective catalytic reduction device. The method or apparatus may determine available reductant and determine a distance to a source of reductant. This may be followed by adjusting a reductant dosing level based upon the available reductant and the distance to the reductant source. The apparatus may be installed in a vehicle and may also regulate in-cylinder emission control variables to reduce NOx emissions.