RF Particulate Filter Diagnostics via Dielectric Resonance

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Solution Overview

Problem

Current methods for detecting upstream engine or system malfunctions that affect particulate filters are inadequate, as they often fail to provide early warnings, are indirect, and lack durability, leading to irreversible damage and excessive particulate matter emissions.

Innovation Solution

A radio frequency (RF) sensing system that directly measures particulate filter loading and monitors exhaust conditions continuously, using electrically-conducting rod antennas to detect changes in dielectric properties, thereby identifying potential failures before they cause irreversible damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensor and model-based approaches are used to detect filter loading, then the system provides indirect estimation of PM loading, but the measurement resolution is insufficient to detect failure conditions resulting in PM escaping at mandated OBD limits

Engineering Contradiction:

ImprovePM loading detection resolutionVSAvoidindirect estimation accuracy

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces mechanical pressure sensors with electromagnetic resonance-based sensing. The system uses resonant frequency shifts of a probe inserted into the filter to directly measure PM loading, eliminating the indirect pressure-based estimation and achieving the required measurement precision for detecting PM escape at OBD limits.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If soot sensors are deployed downstream of the filter, then the system can monitor soot concentration, but the sensors cannot detect upstream malfunctions or provide advance warning of potential failures

Engineering Contradiction:

Improveearly warning capabilityVSAvoiddetection delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent places the sensing probe directly within the filter medium to monitor PM loading in real-time before failures occur. This preliminary positioning enables early detection of upstream malfunctions and provides advance warning of potential filter failures, eliminating the detection delay inherent in downstream soot sensor approaches.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If accumulation type soot sensors are used, then the system can monitor soot levels, but the sensors require periodic regeneration that consumes additional energy and does not provide continuous monitoring

Engineering Contradiction:

Improvecontinuous monitoring capabilityVSAvoidregeneration energy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements continuous monitoring through a resonance-based sensing probe that operates without interruption. The system continuously tracks PM loading by measuring resonant frequency shifts, eliminating the need for periodic regeneration cycles and providing uninterrupted productivity monitoring without additional energy consumption.

Inventive Principle:

Principle #20Continuity of useful action

4Reliability

If pressure-drop measurements are used to monitor filter condition, then the system can detect filter loading, but the measurements are unreliable at low exhaust flow conditions, during regeneration, during frequent transient operations, and following filter aging

Engineering Contradiction:

Improvemeasurement reliability across operating conditionsVSAvoidoperating condition range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from measuring pressure drop (flow-dependent parameter) to measuring resonant frequency (material-property-dependent parameter). This parameter change enables reliable PM loading detection across all operating conditions including low flow, regeneration, transient operations, and aged filters, as resonant frequency directly reflects PM mass in the filter independent of flow conditions.

Inventive Principle:

Principle #35Parameter changes

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 RF sensing system enables early detection of upstream failures, continuous monitoring, and increased durability, providing direct measurements of particulate filter loading and exhaust conditions, reducing the risk of irreversible damage and excessive emissions.

Implementation Method 1

A radio frequency (RF) sensor and system for sensing, control, and diagnostics that improves the control and operation of the particulate filter as well as the state of the filter for on-board diagnostics applications and detects engine system malfunctions

Methodology Applied

Scientific EffectDielectric properties: Dielectric

Data Source

PatentEP3433476B1Radio frequency process sensing, control, and particulate matter diagnostics system

Publication Date: 2021.07.21 CTS CORP

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AI summary

A radio frequency sensing, control, and particulate matter diagnostics network and system and method and, more specifically, a radio frequency particulate filter diagnostics system comprising a housing 108 including an inlet connected to a source of particulate matter, a particulate filter 114 in the housing and adapted for filtering the particulate matter, and a radio frequency sensor adapted to detect conditions of abnormal particulate filter or system operation and including at least one radio frequency probe 124 configured to be in contact with the housing for the particulate filter housing and adapted to receive radio frequency signals and a radio frequency control unit in communication with the radio frequency probe.