EP0410685A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
System for reducing noise level in vehicular cabin
Assignee: Nissan Motor Co Ltd
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Filing: 1990-07-24
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Granted: —
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Expires: 2010-07-24
Abstract
Abstract The system produces an acoustic vibration canceling noise creative vibration induced in synchronism with an engine revolution. The system generates a rectangular wave signal having a 50% duty cycle. The system includes means for producing a periodic signal having an interval half of a period of the noise creative vibration. The signal level of the rectangular signal is switched between HIGH and LOW levels alternately at timings of occurrence of the periodic signal. A crank angle sensor (1) produces the periodic signal. A rectangular wave generator circuit (11), in conjunction with a clock, produces a digital signal representing the rectangular signal. The digital signal is adjusted in phase (at 13) and amplitude (at 14), in response to engine load data and engine speed data, and an acoustic vibration whose frequency and amplitude are represented by the adjusted digital signal is reproduced by a speaker (34).
Inventors
- 👤 Yoshiharu Nakaji
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:57
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/16; G10K11/175; G10K11/178; G10K11/1785; G10K11/17853; G10K11/1781; G10K11/17821; G10K11/17823; G10K11/1787; G10K11/17873; G10K2210/00; G10K2210/10; G10K2210/121; G10K2210/128; G10K2210/30; G10K2210/301; G10K2210/3028; G10K2210/3033; G10K2210/3039; G10K2210/3045
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
152 words
A system for lowering noise level in a vehicular cabin, comprising: first means (1) for periodically generating a first pulse signal in synchronism with an engine revolution, the first pulse signal having a pulse period half of a period of a noise creative vibration induced in synchronism with engine revolution; second means (11), responsive to the first pulse signal, for generating a rectangular wave signal switching signal level between a first lower level (L) and a second higher level (H) alternately at every occurrence of the first pulse signal; third means for converting the rectangular wave signal into a digital signal representative thereof; fourth means (23,13,14) for processing the digital signal for adjusting signal phase and amplitude and outputting an adjusted digital signal having an adjusted amplitude; and fifth means (31-34) for reproducing an acoustic vibration having frequency and amplitude represented by the adjusted digital signal, for canceling the noise creative vibration.
Claim 2
Independent Claim
152 words
A system for lowering noise level in a vehicular cabin, comprising: first means (1) for periodically generating a first pulse signal in synchronism with an engine revolution, the first pulse signal having a pulse period half of a period of a noise creative vibration induced in synchronism with engine revolution; second means (11), responsive to the first pulse signal, for generating a rectangular wave signal switching signal level between a first lower level (L) and a second higher level (H) alternately at every occurrence of the first pulse signal; third means for converting the rectangular wave signal into a digital signal representative thereof; fourth means (23,13,14) for processing the digital signal for adjusting signal phase and amplitude and outputting an adjusted digital signal having an adjusted amplitude; and fifth means (31-34) for reproducing an acoustic vibration having frequency and amplitude represented by the adjusted digital signal, for canceling the noise creative vibration.
Claim 3
Dependent Claim
46 words
A system as claimed in claim 1, further comprising sixth means (12,21,22) for monitoring an engine driving condition for providing engine driving condition indicative data, the fourth means (23,13,14) deriving magnitude of phase shift and amplitude on the basis of the engine deriving condition indicative data.
Claim 4
Dependent Claim
47 words
A system as claimed in claim 2, wherein the first means comprises a crank angle sensor (1) producing a periodic signal in synchronism with the engine revolution, and the sixth means comprises means (12) for deriving engine speed data on the basis of the said periodic signal.
Claim 5
Dependent Claim
39 words
A system as claimed in claim 3, wherein the sixth means receives engine load data for deriving magnitude of phase adjustment and adjusts magnitude of amplitude on the basis of the engine speed data and the engine load data.
Claim 6
Dependent Claim
18 words
The system as claimed in claim 4, wherein the engine load data is a fuel injection control signal.
Claim 7
Independent Claim
25 words
A system as claimed in any preceding claim, further comprising filtering means (15) for receiving the adjusted digital signal and removing a high harmonic component.
Claim 8
Dependent Claim
22 words
A system as claimed in claim 6, wherein the filtering means (15) comprises a plurality of band-pass filters having mutually different pass-bands.
Claim 9
Dependent Claim
55 words
A system as claimed in claim 7, wherein the filtering means (15) comprises at least a first filter having a minimum pass band corresponding to a minimum frequency of the noise creative vibration and a predetermined maximum pass-band, and a second filter having a minimum pass-band corresponding to the maximum pass-band of the first filter.
Claim 10
Independent Claim
29 words
A system as claimed in any preceding claim, wherein the first means generates the first pulse signal with an interval half of an interval of a crank reference signal.
Claim 11
Independent Claim
35 words
A system as claimed in any preceding claim, wherein the third means converts the rectangular wave signal into a digital signal by supplying the rectangular wave signal and a sampling pulse to an AND gate.
References Cited (Backward Citations)
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