EP0479367A2
Expired / Lapsed
EP
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Method and apparatus for attenuating engine generated noise
Assignee: Motors Liquidation Co
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Filing: 1991-09-20
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Granted: —
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Expires: 2011-09-20
Abstract
Abstract A method and apparatus are described for attenuating harmonic noise components contained within noise generated by an internal combustion engine (10), based upon the rotation of the engine (10) during its operating cycle. A signal representing selected multiple harmonic noise components is generated from a table of values, based upon the engine rotation. This signal is adaptively filtered to produce a cancelling waveform, which is superimposed onto the engine noise to attenuate the selected multiple noise harmonics. The method and apparatus are useful for selecting and attenuating dominant noise harmonics produced at different engine speeds or by different types of engines, and the dominant harmonics of different forms of noise produced by the same engine.
Inventors
- 👤 Donald Paul Pfaff
- 👤 Natalie Ann Parks
- 👤 Nick S. Kapsokavathis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 04:05
CPC Classifications
F; F01; F01N; F01N1/00; F01N1/06; F01N1/065; G; G10; G10K; G10K11/00; G10K11/16; G10K11/175; G10K11/178; G10K11/1781; G10K11/17821; G10K11/17823; G10K11/1785; G10K11/17853; G10K11/17854; G10K11/1787; G10K11/17879; G10K11/17883; G10K2210/00; G10K2210/10; G10K2210/121; G10K2210/30; G10K2210/301; G10K2210/3032; G10K2210/3033; G10K2210/3039; G10K2210/3045; G10K2210/3046; G10K2210/321; G10K2210/3211
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
70 words
A method of attenuating noise generated in an engine, which noise is related to engine rotational speed, comprising the steps of deriving an engine position signal indicative of the rotational position of the engine in an operating cycle; generating a noise signal representative of selected harmonic noise components on the basis of the engine position signal; and attenuating noise generated by the engine on the basis of the noise signal.
Claim 2
Dependent Claim
60 words
A method according to claim 1, wherein the noise signal is generated from a predetermined schedule of values as a function of the engine position signal, the values in the schedule being determined by summing separate sinusoidal terms, each sinusoidal term corresponding to a selected harmonic component and having an argument related to an integer multiple of the engine position.
Claim 3
Dependent Claim
39 words
A method according to claim 1, comprising the step of deriving an engine speed signal indicative of the engine rotational speed; the noise signal being generated on the basis of the engine position signal and the engine speed signal.
Claim 4
Dependent Claim
66 words
A method according to claim 3, wherein the noise signal is generated from a table comprising a plurality of predetermined schedules, each schedule being associated with a different engine rotational speed and including values determined by summing separate sinusoidal terms, each term corresponding to a selected harmonic component for the associated engine speed and having an argument related to an integer multiple of the engine position.
Claim 5
Independent Claim
49 words
A method according to any one of claims 1 to 4, wherein the step of attenuating noise generated by the engine includes the steps of developing a noise cancelling waveform by adaptively filtering the noise signal; and superimposing the noise cancelling waveform on the noise generated by the engine.
Claim 6
Dependent Claim
22 words
A method according to claim 5, wherein the noise signal is adaptively filtered using a Filtered X Least Mean Squares (LMS) algorithm.
Claim 7
Independent Claim
70 words
A method according to any one of claims 1 to 4, wherein the step of attenuating noise generated by the engine includes the steps of deriving an indication of engine loading; modulating the amplitude of the noise signal as a function of engine loading; developing a noise cancelling waveform by adaptively filtering the amplitude modulated noise signal; and superimposing the noise cancelling waveform on the noise generated by the engine.
Claim 8
Dependent Claim
24 words
A method according to claim 7, wherein the amplitude modulated noise signal is adaptively filtered using a Filtered X Least Mean Squares (LMS) algorithm.
Claim 9
Independent Claim
22 words
A method according to any preceding claim, wherein the harmonic noise components selected for attenuation are acoustic noise propagating from the engine.
Claim 10
Dependent Claim
24 words
The method of claim 1, wherein the multiple harmonic noise components selected for attenuation propagate from the engine in the form of mechanical vibrations.
Claim 11
Dependent Claim
82 words
Apparatus for attenuating noise generated in an engine, which noise is related to engine rotational speed, the apparatus comprising speed deriving means (42-50) for deriving an engine position signal indicative of the rotational position of the engine (10) in an operating cycle; processing means (26) for generating a noise signal representative of selected harmonic noise components on the basis of the engine position signal; and attenuating means (28,32,36) for attenuating noise generated by the engine on the basis of the noise signal.
References Cited (Backward Citations)
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