Diesel Particulate Sensor with Protective Dome

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing particulate matter sensors in exhaust systems face issues with contamination from water droplets and larger particulates, leading to reduced sensitivity and inaccurate readings, which can result in false indications of diesel particulate filter (DPF) degradation and unnecessary filter replacements.

Innovation Solution

A particulate matter sensor assembly with a cylindrical design featuring a sensor element positioned above an annular space and a dome at the top end, where the sensor element is surrounded by perforations that direct exhaust gas flow to ensure uniform deposition and minimize contamination, with oppositely charged electrodes on dividers to enhance particulate capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor element is positioned closer to the inlet apertures to capture more incoming particulates, then the sensor sensitivity is improved, but the sensor element becomes more vulnerable to contamination by water droplets and larger particulates

Engineering Contradiction:

Improvesensor sensitivityVSAvoidcontamination from water droplets and larger particulates

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

A protective coating is applied to the sensor element to act as an intermediary layer. This coating allows the sensor to capture particulates effectively while protecting the sensor element from direct contamination by water droplets and larger particulates, thus maintaining sensitivity without vulnerability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin protective film or coating is introduced over the sensor element. This film is permeable enough to allow particulate matter to reach the sensor while being impermeable to larger contaminants like water droplets, thereby preserving sensor sensitivity while providing protection.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-affected harmful factors

If additional protective coating is added to protect the sensor element from direct impingement of larger particulates and water droplets, then the sensor is protected from contamination, but the electrostatic attraction between charged soot particles and the electrodes is reduced

Engineering Contradiction:

Improveprotection from contaminationVSAvoidsensor sensitivity

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The properties of the protective coating are carefully controlled and optimized. The coating is designed with specific thickness, porosity, and surface charge characteristics that allow it to block water droplets and large particulates while remaining permeable to soot particles and maintaining electrostatic attraction for particle capture.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The protective coating is formulated as a composite material with specific properties. It combines materials that provide mechanical protection against water droplets while maintaining electrostatic properties that enable soot particle attraction, thus achieving both protection and sensitivity.

Inventive Principle:

Principle #40Composite materials

3Device complexity

If the sensor is mounted at the bottom of the exhaust pipe to utilize the cylindrical assembly design, then the sensor structure is simplified, but water condensing at the bottom of the exhaust pipe may overflow into the sensor element

Engineering Contradiction:

Improvesensor structureVSAvoidwater overflow into sensor element

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The harmful effect of water accumulation is extracted and isolated from the sensor element. The dome structure creates a separate water collection chamber that captures condensing water before it can reach the sensor, effectively removing the water threat from the sensor environment.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The sensor assembly is segmented into distinct functional zones: a water collection dome separated from the sensor element, and a protected sensor chamber. This segmentation physically isolates the sensor from water overflow while maintaining structural simplicity.

Inventive Principle:

Principle #1Segmentation

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 design improves sensor reliability and accuracy, enabling better diagnosis of DPF health and reducing warranty costs associated with replacing functional filters by providing more precise emissions compliance and extending exhaust component life.

Implementation Method 1

additional protective coating may be required to protect the soot sensor element from direct impingement of larger particulates and water droplets. Adding additional protective layer may reduce the electrostatic attraction between the charged soot particles and the electrodes of the sensor element

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentUS10392999B2Method and system for exhaust particulate matter sensing

Publication Date: 2019.08.27 FORD GLOBAL TECH LLC

AI summary

Methods and systems are provided for a particulate matter sensor positioned downstream of a diesel particulate filter in an exhaust system. In one example, a particulate matter sensor may include a cylindrical assembly with a circular plate and a plurality of dividers located therein.