Particulate Matter Sensor Conductance Differential Analysis

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Solution Overview

Problem

Current particulate matter sensors in diesel engines face challenges such as long response times, lack of real-time measurement, and inaccurate soot level detection due to deadband zones and anomalies like large particle strikes and blow-offs, which corrupt the particulate matter concentration assessment.

Innovation Solution

The method involves calculating particulate matter mass, flux, and concentration using the second differential of conductance signals during the deadband and active zones, correcting for anomalies by identifying and removing error effects from large particle strikes and blow-offs, and summing data from both zones to determine total accumulated particulate matter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor uses a bias resistor in the circuit to diagnose the sensor itself, then the sensor can be self-diagnosed, but the deadband zone increases and real-time measurement capability is lost

Engineering Contradiction:

Improvesensor self-diagnosis capabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The measurement cycle is segmented into deadband zone and active zone, allowing separate handling of sensor diagnosis and real-time measurement. The bias resistor remains active during the deadband zone for self-diagnosis, while the active zone provides real-time soot level measurements without the bias resistor interfering with the conductance signal.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the sensor measures soot during the active zone only, then measurement simplicity is maintained, but response time increases and real-time response is lost

Engineering Contradiction:

Improvemeasurement cycle simplicityVSAvoidresponse time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The sensor performs preliminary measurements during the deadband zone before the active zone begins. By calculating particulate matter mass, flux, and concentration using the second differential of conductance signals during the deadband zone, the system provides early warnings and real-time response without waiting for the active zone, thereby reducing overall response time while maintaining measurement simplicity.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the sensor calculates particulate matter using time-integrated output, then the measurement method is simple, but real-time response capability is lost

Engineering Contradiction:

Improvecalculation method simplicityVSAvoidreal-time response information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The second differential of conductance signals serves as an intermediary parameter that bridges the simple time-integrated measurement approach with real-time response capability. By using the second differential of conductance during the deadband zone as an intermediate calculation step, the system derives real-time particulate matter mass, flux, and concentration information without complicating the overall measurement methodology.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Device complexity

If the sensor ignores the deadband zone as previously done, then the measurement process is simplified, but measurement accuracy during particle deposition is lost

Engineering Contradiction:

Improvemeasurement process complexityVSAvoidsoot level detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The deadband zone, previously considered a harmful period with no measurement capability, is converted into a beneficial measurement period. By utilizing the deadband zone for real-time particulate matter calculations using the second differential of conductance signals, the system transforms this previously useless time period into a valuable source of early detection data, improving measurement precision without increasing process complexity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 provides accurate, real-time particulate matter measurements, reducing response times and improving diagnostic accuracy by correcting for anomalies, enabling quicker and more precise calculations of particulate matter mass, flux, and concentration.

Implementation Method 1

the sensor's electric resistance decreases as the initially non-conductive substrate surface between electrodes becomes gradually more electrically conductive due to the deposited particulate matter (PM) or soot

Methodology Applied

Scientific EffectElectrical Conductivity: Conduction (electrical)

Implementation Method 2

the sensor undergoes regeneration to prepare the sensor to again measure the accumulation of soot

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS10329989B2Particulate matter detection system and method

Publication Date: 2019.06.25 BORGWARNER US TECHNOLOGIES LLC

AI summary

A method of quantifying a particulate matter in an exhaust stream includes the steps of accumulating a particulate matter on a sensor. The sensor provides a signal that varies based upon an amount of the particulate on the sensor. The sensor includes a measurement cycle that includes a deadband zone, followed by an active zone, which is followed by a regeneration zone. The particulate matter is calculated after an end of the deadband zone is reached and prior to an end of the measurement cycle.