Device and method for altering the acoustic signature of an internal combustion engine
US5042444A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1990 |
| Grant date | Aug 27, 1991 |
| Priority date | — |
| Expiry date | Mar 7, 2010 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2200/025
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.