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EP0097416A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Microwave detection of soot content in a particulate trap

Assignee: Motors Liquidation Co
•
Filing: 1983-04-26
•
Granted: —
•
Expires: 2003-04-26
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Abstract

Abstract Conductive particulates in the form of soot are collected from diesel engine exhaust gases on a porous wall monolithic ceramic filter (22) in such a way that the soot is substantially uniformly distributed throughout the filter (22). The filter (22) is housed in a chamber (18) having the property of a microwave resonant cavity and the cavity is excited with microwave energy (36, 38). As the particulates are collected the cavity appears to the microwaves to have an increasing dielectric constant even though the matter being accumulated is conductive rather than dielectric so that, as collected on the porous filter (22), it has the property of an artificial dielectric. The response of the cavity to the microwave energy is monitored to sense the effect of the dielectric constant of the material within the cavity to provide a measure of the soot content in the filter.

Inventors

  • 👤 Louis Leonard Nagy
  • 👤 Michael James O'rourke
  • 👤 David Sturge Eddy

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-08 16:36
CPC Classifications
G; G01; G01N; G01N22/00; F; F01; F01N; F01N9/00; F01N9/002; F01N2560/00; F01N2560/05; F01N2560/12; F02; F02B; F02B3/00; F02B3/06; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/40

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 139 words
A method of detecting and measuring the accumulation of a substance in a chamber (18) by means of the reflection of microwave energy, characterised in that the substance accumulated comprises conductive particulates being collected from diesel engine exhaust gases on a collection medium (22) formed of dielectric material in said chamber (18)having the property of a microwave resonance cavity, and the method comprises the steps of: collecting particulates on the medium (22) in a pattern substantially uniformly dispersed throughout the cavity whereby the dielectric loading of the cavity increases with increasing conductive particulate content.exciting the cavity with microwave energy (36,38), and monitoring the response of the cavity to the microwave energy to sense the effective dielectric constant of the material within the cavity, thereby providing a measure of the quantity of conductive particulates retained on the collection medium (22).
Claim 2
Independent Claim 139 words
A method of detecting and measuring the accumulation of a substance in a chamber (18) by means of the reflection of microwave energy, characterised in that the substance accumulated comprises conductive particulates being collected from diesel engine exhaust gases on a collection medium (22) formed of dielectric material in said chamber (18)having the property of a microwave resonance cavity, and the method comprises the steps of: collecting particulates on the medium (22) in a pattern substantially uniformly dispersed throughout the cavity whereby the dielectric loading of the cavity increases with increasing conductive particulate content.exciting the cavity with microwave energy (36,38), and monitoring the response of the cavity to the microwave energy to sense the effective dielectric constant of the material within the cavity, thereby providing a measure of the quantity of conductive particulates retained on the collection medium (22).
Claim 3
Dependent Claim 120 words
A method of detecting the accumulation of conductive particulates being collected from diesel engine exhaust gases according to claim 1, characterised in that the conductive particulates are collected on a honeycomb filter (22) formed of dielectric material in said chamber (18) having the property of a microwave resonance cavity, the filter (22) defining a plurality of parallel passages (26, 27) separated by porous walls (24) having alternate passages (26) blocked at one end (30) and the remaining passages (27) blocked at the other end (28),so that the exhaust gases flow through the porous walls (24); and the particulates are collected on the porous walls in a pattern sufficiently uniformly dispersed throughout the cavity as to resemble an artificial dielectric material.

References Cited (Backward Citations)

US3238452A Cited
US3843257A Cited
US4042879A Cited
US4345202A Cited

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