Diesel Particulate Filter Soot Estimation via Restriction Sensitivity

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Solution Overview

Problem

Existing methods for estimating soot levels in diesel engine exhaust particulate filters are not accurate, leading to premature regeneration and increased fuel usage, as they fail to differentiate between transient engine operations and actual soot load, resulting in inefficient fuel consumption and potential filter degradation.

Innovation Solution

A method that calculates a pressure change-based soot load estimate and a model-based soot accumulation estimate using pressure changes across the particulate filter, with a transition to the model-based estimate when restriction sensitivity falls below a threshold, ensuring accurate soot level determination and preventing premature regeneration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If pressure change based soot load estimation is used, then the estimation method is simple, but the accuracy deteriorates due to inability to differentiate transient operations from actual soot load

Engineering Contradiction:

Improveestimation method complexityVSAvoidsoot load estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system dynamically switches between two estimation methods (pressure change based and model based) depending on operating conditions. The controller selects which method to use based on real-time analysis of engine operation state, making the estimation system adaptive rather than static. This resolves the contradiction by using the simple pressure change method during steady-state operations while switching to the more accurate model-based method during transient operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the estimation approach parameter based on operating conditions. When transient engine operations are detected, the system transitions from using pressure change alone to using a comprehensive model that incorporates multiple parameters including pressure change, engine load, speed, and temperature. This parameter change allows the system to maintain simplicity during normal operation while achieving high accuracy during critical transient phases.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If regeneration cycle is performed frequently to ensure filter cleanliness, then emissions compliance is maintained, but fuel consumption increases

Engineering Contradiction:

Improveemissions complianceVSAvoidfuel consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system implements feedback control by continuously monitoring soot load estimates and comparing them against threshold values. The regeneration decision is based on accurate real-time feedback from the dual-method estimation system, which distinguishes between transient pressure changes and actual soot accumulation. This prevents premature regeneration triggers while ensuring regeneration occurs when truly necessary, optimizing the balance between emissions compliance and fuel consumption.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of soot load using the simple pressure change method during normal operation to determine if regeneration is needed. Only when the more accurate model-based estimation confirms high soot load does the system trigger regeneration. This preliminary filtering action prevents unnecessary regeneration cycles while ensuring that when regeneration is triggered, it is based on accurate soot load assessment.

Inventive Principle:

Principle #10Preliminary action

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 estimation of soot levels, optimizing regeneration timing and reducing fuel consumption by distinguishing between transient engine operations and actual soot load, thereby extending filter service life and maintaining emissions compliance.

Implementation Method 1

an exhaust particulate filter within an exhaust system of the engine purposed to reduce the amount of particulate matter released into the atmosphere

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 2

perform a regeneration cycle for the exhaust particulate filter that causes exhaust gas temperatures to rise to a level to regenerate the exhaust particulate filter by burning the trapped particulate matter

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

generates a pressure change based soot load estimate within the exhaust gas particulate filter at the first time based upon a pressure change from the input to the output of an exhaust gas particulate filter

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Data Source

PatentUS8266890B2Preventing soot underestimation in diesel particulate filters by determining the restriction sensitivity of soot

Publication Date: 2012.09.18 INT ENGINE INTPROP CO LLC

AI summary

A method of determining a need to perform regeneration of a diesel particulate filter in a diesel engine exhaust predicts a soot load of a diesel particulate filter with a pressure change based soot load estimate based upon a pressure change across the diesel particulate filter at a first time and a second time. A restriction sensitivity for the diesel particulate filter is calculated based upon the pressure change across the diesel particulate filter at the first time and the second time. The method transitions from the pressure change based soot load estimate to a model based soot accumulation estimate of the soot load of the diesel particulate filter upon the restriction sensitivity falling below a predetermined threshold. Regeneration of the diesel particulate filter is requested after the estimated soot level reaches a preset level based upon the soot accumulation model.