US4608855A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for the recognition of knocking of an Otto engine
Assignee: Schaeffler Engineering GmbH
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Filing: 1984-07-24
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Granted: 1986-09-02
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Expires: 2004-07-24
Abstract
Abstract A circuit for the recognition of knocking of an Otto engine includes a spark plug in the combustion chamber of a cylinder which also serves as an ionic current probe. Both an excitation voltage generator and, an evaluation circuit for the measuring voltage are coupled to the high-voltage ignition circuit. The excitation voltage generator is provided by a high-frequency oscillator. The input coupling of the excitation voltage is effected non-galvanically. The evaluating circuit comprises an amplitude demodulator for the high-frequency oscillations. The benefits of the present invention resulting from a knock recognition circuit of such a configuration that critical electrical components and galvanic coupling are avoided.
Inventors
- 👤 Reinhold Blauhut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:41
CPC Classifications
G; G01; G01L; G01L23/00; G01L23/22; G01L23/221; F; F02; F02P; F02P17/00; F02P17/12; G01L23/225; F02B; F02B1/00; F02B1/02; F02B1/04; F02P2017/003; F02P2017/125; F02P2017/128
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
89 words
A circuit for the recognition of knocking of an engine having a high-voltage ignition circuit and having a spark plug in the combustion chanber of a cylinder which also serves as an ionic current probe, said knock recognition circuit comprising: (a) an excitation voltage generator comprising a high frequency osicllator non-galvanically coupled to the spark plug for producing high frequency voltage oscillation; and (b) an evaluation circuit for measuring voltage coupled into said high-voltage ignition circuit, wherein said evaluation circuit includes an amplitude demodulator for the high-frequency voltage oscillation.
Claim 2
Dependent Claim
89 words
A circuit for the recognition of knocking of an engine having a high-voltage ignition circuit and having a spark plug in the combustion chanber of a cylinder which also serves as an ionic current probe, said knock recognition circuit comprising: (a) an excitation voltage generator comprising a high frequency osicllator non-galvanically coupled to the spark plug for producing high frequency voltage oscillation; and (b) an evaluation circuit for measuring voltage coupled into said high-voltage ignition circuit, wherein said evaluation circuit includes an amplitude demodulator for the high-frequency voltage oscillation.
Claim 3
Dependent Claim
19 words
A circuit according to claim 1 wherein said high-frequency oscillator operates at a frequency between 15 and 100 kHz.
Claim 4
Dependent Claim
18 words
A circuit according to claim 2 wherein said amplitude demodulator is a synchronous demodulator having a product detector.
Claim 5
Dependent Claim
29 words
A circuit according to claim 3 wherein said evaluation circuit further comprises a filter having a pass-band of 8 to 10 kHz which is connected to the amplitude demodulator.
Claim 6
Dependent Claim
19 words
A circuit according to claim 4 wherein the output of said filter is connected to a threshold value circuit.
Claim 7
Dependent Claim
26 words
A circuit according to claim 1 for use in a distributorless ignition circuit wherein the high-frequency osicllator generates high frequency pulses supplied to an ignition transistor.
Claim 8
Dependent Claim
25 words
A circuit according to claim 1 for use in an ignition circuit with a distributor wherein the coupling of the high-frequency oscillator comprises a capacitor.
Claim 9
Dependent Claim
16 words
A circuit according to claim 6 wherein the coupling of the evaluation circuit comprises a capacitor.
Claim 10
Dependent Claim
17 words
A circuit according to claim 1 wherein the coupling of the evaluation circuit comprises a high-ohmic resistor.
Claim 11
Dependent Claim
17 words
A circuit according to claim 6 wherein the coupling of the evaluation circuit comprises a current transformer.
References Cited (Backward Citations)
US3286164A
Cited
DE2443413A1
Cited
US4233943A
Cited
FR2433105A1
Cited
DE3006665A1
Cited
US4491110A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |