Active vibratory noise control apparatus for cancelling noise inside a vehicle

摘要

An active vibratory noise control apparatus (20; 30) reduces vibratory noise which is produced in the passenger compartment of a vehicle (41) based on vibratory noise generated by a variable-cylinder internal combustion engine (42) that can selectively be operated in a full-cylinder operation mode in which all of the cylinders are operated and a partial-cylinder operation mode in which some of the cylinders are out of operation. The active vibratory noise control apparatus has a partial-cylinder operation mode determining circuit (13) for determining whether the variable-cylinder internal combustion engine is in the partial-cylinder operation mode or not so that the noise control apparatus can be controlled. Depending on a determined result from the partial-cylinder operation mode determining circuit (13), in one embodiment a transistor (52) is turned on or off to switch an amplifying circuit (5) which drives a speaker (6) into and out of operation. In another embodiment, the means for controlling the operation of the noise control apparatus (20; 30) comprises basic frequency changing means (151) for changing the frequency of a basic signal which is a frequency to be controlled, depending on the number of active cylinders determined by the number-of-active-cylinder determining means (17).