Patent US5390546A successfully refreshed from Google Patents.
US5390546A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber optic diaphragm sensors for engine knock and misfire detection
Assignee: Individual
•
Filing: 1993-07-01
•
Granted: 1995-02-21
•
Expires: 2013-07-01
Abstract
Abstract The modulation depth of a fiber optic diaphragm sensor is increased by tapering the tip end of the optical fiber or fiber bundle. In a second embodiment, the modulation depth is increased by mechanically leveraging the diaphragm movement relative to the tip end of the optical fiber or fiber bundle. In either embodiment, the operating temperature of the tip end of the optical fiber or fiber bundle can be reduced relative to the operating temperature of the diaphragm. Thus, the diaphragm sensor can be directly exposed to combustion temperatures in an internal combustion engine and advantageously the sensor can be embodied in a spark plug adjacent the electrodes.
Inventors
- 👤 Marek T. Wlodarczyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:50
CPC Classifications
G; G01; G01L; G01L23/00; G01L23/22; G01L23/221; G01L23/08; G01L23/16; G01L9/00; G01L9/0041; G01L9/0076; G01L9/0077; G01M; G01M15/00; G01M15/04; G01M15/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
164 words
In a fiber optic diaphragm sensor comprising a body having a cavity approximately 3 mm across therein, a diaphragm attached to the body and partially enclosing the cavity, the diaphragm being moveable in response to changes in fluid pressure exerted upon the diaphragm, and an optical fiber inserted in the body with the tip end of the optical fiber disposed to inject a light beam into the cavity and receive a reflected light beam, the improvement comprising moveable reflective means interposed in the cavity to intercept and reflect back the injected light beam, mechanical means interconnecting the reflective means to the diaphragm whereby movement of the diaphragm in response to changes in fluid pressure activates responsive movement of the reflective means and modulation of the light beam reflected back to the tip end of the optical fiber, said mechanical means interposed between the diaphragm and reflective means to provide a substantial temperature differential between the diaphragm and reflective means when the diaphragm is hot.
Claim 2
Dependent Claim
164 words
In a fiber optic diaphragm sensor comprising a body having a cavity approximately 3 mm across therein, a diaphragm attached to the body and partially enclosing the cavity, the diaphragm being moveable in response to changes in fluid pressure exerted upon the diaphragm, and an optical fiber inserted in the body with the tip end of the optical fiber disposed to inject a light beam into the cavity and receive a reflected light beam, the improvement comprising moveable reflective means interposed in the cavity to intercept and reflect back the injected light beam, mechanical means interconnecting the reflective means to the diaphragm whereby movement of the diaphragm in response to changes in fluid pressure activates responsive movement of the reflective means and modulation of the light beam reflected back to the tip end of the optical fiber, said mechanical means interposed between the diaphragm and reflective means to provide a substantial temperature differential between the diaphragm and reflective means when the diaphragm is hot.
Claim 3
Dependent Claim
26 words
The fiber optic diaphragm sensor of claim 1 wherein the interconnecting mechanical means leverages movement of the reflective means to magnify the movement of the diaphragm.
Claim 4
Dependent Claim
46 words
The fiber optic diaphragm sensor of claim 1 wherein the interconnecting mechanical means is connected to the diaphragm substantially at the location of maximum diaphragm amplitude and to the reflective means at a location substantially spaced from the location of maximum amplitude of the reflective means.
Claim 5
Dependent Claim
51 words
The fiber optic diaphragm sensor of claim 1 wherein the reflective means is attached to the body by a fulcrum and the interconnecting mechanical means is connected to the reflective means at a location between the fulcrum and the location at which the light beam is centered on the reflective means.
Claim 6
Dependent Claim
157 words
A spark plug and sensor combination comprising a ceramic core and first electrode extending therefrom, a sleeve surrounding the core and a second electrode extending from the sleeve, a small bore in the spark plug adjacent the electrodes and a sensor located in the small bore, the sensor comprising a body having a cavity therein, a diaphragm attached to the body and partially enclosing the cavity, the diaphragm being moveable in response to changes in rigid pressure exerted upon the diaphragm, optical means to inject a light beam into the cavity and receive a reflected light beam, moveable reflective means interposed in the cavity to intercept and reflect back the injected light beam, mechanical means interconnecting the reflective means to the diaphragm to cause movement of the reflective means in concert with movement of the diaphragm, said mechanical means interposed to provide a substantial temperature differential between the diaphragm and reflective means when the diaphragm is hot.
Claim 7
Dependent Claim
157 words
A spark plug and sensor combination comprising a ceramic core and first electrode extending therefrom, a sleeve surrounding the core and a second electrode extending from the sleeve, a small bore in the spark plug adjacent the electrodes and a sensor located in the small bore, the sensor comprising a body having a cavity therein, a diaphragm attached to the body and partially enclosing the cavity, the diaphragm being moveable in response to changes in rigid pressure exerted upon the diaphragm, optical means to inject a light beam into the cavity and receive a reflected light beam, moveable reflective means interposed in the cavity to intercept and reflect back the injected light beam, mechanical means interconnecting the reflective means to the diaphragm to cause movement of the reflective means in concert with movement of the diaphragm, said mechanical means interposed to provide a substantial temperature differential between the diaphragm and reflective means when the diaphragm is hot.
Claim 8
Dependent Claim
27 words
The spark plug and sensor combination of claim 5 wherein the interconnecting mechanical means leverages movement of the reflective means to magnify the movement of the diaphragm.
Claim 9
Dependent Claim
34 words
The spark plug and sensor combination of claim 5 wherein the ceramic core and first electrode are offset from the center of the spark plug and the small bore is located in the sleeve.
References Cited (Backward Citations)
DE1024266B
Cited
FR1291996A
Cited
US4293188A
Cited
US4521683A
Cited
US4620093A
Cited
US4781059A
Cited
US4753109A
Cited
US4919099A
Cited
WO1989011031A1
Cited
US5052214A
Cited
US4924870A
Cited
EP0392650A1
Cited
US4932263A
Cited
US4932262A
Cited
US5072617A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-20 | 1998-08-22 | 1999-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-20 | 2002-08-22 | 2003-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-20 | 2006-08-22 | 2007-02-21 | $7700.00 | Window Closed / Lapsed |