Noise control apparatus for internal combustion engine
US5571239A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1995 |
| Grant date | Nov 5, 1996 |
| Priority date | — |
| Expiry date | Nov 16, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10K2210/511
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A noise control apparatus has a thermal-type air flow meter for detecting engine load, an engine speed sensor for detecting engine speed, and an intake temperature sensor for detecting intake temperature. The engine load is detected based on the surging components of the signal from the air flow meter. An intake pipe is provided with a speaker that produces a noise control wave in accordance with a control signal from a controller. The controller has a memory that stores map data for noise control waves that are equal in sound pressure but opposite in phase with respect to intake noise. The map data regarding sound pressure and phase correspond to the engine load and speed on the basis of a reference temperature. A CPU of the controller computes a map-reading engine speed value based on a wavelength of intake noise that is determined based on intake temperature and engine speed, such that the map-reading engine speed value provides at the reference temperature substantially the same wavelength as that of the intake noise. The CPU generates a noise control wave signal based on the map-reading engine speed value and engine load information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.