The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 27, 1991
Filed:
Mar. 07, 1990
Paul A Hayes, Columbus, IN (US);
Thomas E Reinhart, Columbus, IN (US);
Terrence M Shaw, Columbus, IN (US);
Cummins Engine Company, Inc., Columbus, IN (US);
Abstract
An apparatus and method for altering the acoustic signature of an internal combustion engine is disclosed. Several techniques for altering the acoustic signature of an engine are shown, including time-varying, disabling or cutout of individual cylinders of an engine in a random fashion in order to reduce the periodic characteristics of the exhaust noise of the engine. Alternate embodiments include offsetting crank pins to transform an even firing engine into an uneven firing engine, inhibiting the fueling of individual cylinders, and inhibiting the ignition signals provided to individual cylinders. A combination of the above techniques may also be implemented in order to disperse the exhaust noise energy present over a wide frequency range, making acoustic detection of the exhaust signature difficult. Cylinder cutout schemes are implemented over a single or multiple engine cycle to disperse exhaust noise pulses over time and randomize measurable spectral noise composition.