Particulate Sensor Discharge Electrode Extraction
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Solution Overview
Problem
Conventional particulate sensors face issues with restricted controllable frequency, high costs due to complex control circuits, and inability to generate continuous ions using AC high voltage or pulsed DC high voltage, especially when using ceramic laminates with dielectric insulating layers.
Innovation Solution
A particulate sensor design that integrates a discharge electrode with a ceramic laminate, allowing for gaseous discharge generation using constant DC voltage, with a needle-shaped distal end portion projecting outside the laminate to avoid dielectric interference, and includes a heater to maintain insulation and a collection electrode for efficient ion collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC high voltage or pulsed DC high voltage is applied to generate ions by corona discharge, then ion generation is achieved, but controllable frequency is restricted and control circuits become complex increasing cost
Solution Approach 1:
The patent changes the voltage parameter from AC/pulsed DC to constant DC, eliminating the need for frequency control and complex switching circuits. This parameter change maintains ion generation capability while dramatically simplifying the control system.
Solution Approach 2:
The patent extracts the discharge electrode from the ceramic laminate structure, allowing it to be positioned outside the dielectric material. This enables the use of constant DC voltage without the constraints imposed by embedded electrodes within the ceramic layers.
2Stability of the object's composition
If constant DC voltage with small AC component is applied between discharge electrode and ground layer in ceramic laminate, then voltage stability is improved, but continuous ion generation cannot be achieved due to dielectric insulating layer
Solution Approach 1:
The discharge electrode is extracted from within the ceramic laminate and positioned outside, eliminating the dielectric barrier that prevented continuous ion generation. This allows constant DC voltage to effectively produce ions without the voltage fluctuations inherent in AC or pulsed DC systems.
Solution Approach 2:
The patent introduces a protective coating on the discharge electrode that serves as an intermediary layer, enabling the electrode to function effectively in the exhaust gas environment while maintaining stable electrical properties for continuous ion generation under DC voltage.
3Ease of manufacture
If discharge electrode is embedded within ceramic laminate, then structural integration is achieved, but dielectric interference prevents effective gaseous discharge
Solution Approach 1:
The discharge electrode is taken out from the embedded position within the ceramic laminate and repositioned outside. This extraction eliminates the dielectric interference caused by the insulating ceramic layers while the electrode remains structurally integrated through alternative mounting methods.
Solution Approach 2:
The patent transitions the electrode positioning from a two-dimensional embedded planar configuration to a three-dimensional external position, allowing the electrode to protrude into the exhaust gas flow path for effective discharge while maintaining structural integration through proper mounting design.
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 simplifies the control circuit, reduces costs, and enables continuous ion generation and reliable particulate detection by applying constant DC voltage, effectively addressing the limitations of previous technologies.
Implementation Method 1
a corona discharge is produced between the discharge pattern and the second ground pattern
Implementation Method 2
produce gaseous discharge by applying a constant DC voltage to the discharge electrode
Implementation Method 3
ions adhering to the particulates
Implementation Method 4
detects the amount of particulates contained in the exhaust gas by means of a current signal
Data Source
AI summary
A particulate sensor (1) includes an ion source (15) and a reference potential member (45). The particulate sensor (1) detects particulates S contained in a gas under measurement EG by means of ions CP. The ion source (15) includes a ceramic structure (100) having a ceramic laminate (101) and a discharge electrode member (110). The discharge electrode member (110) has an inter-layer portion (112A, 111) embedded between the layers of the ceramic laminate (101) and an exposed portion (112B) extending from the inter-layer portion (112A, 111) to a position outside the ceramic laminate (101). The discharge electrode member (110) generates the gaseous discharge between the reference potential member (45) and the exposed portion (112B) including one or more needle-shaped distal end portions (1125) upon application of a constant DC discharge potential PV2.