NV Countermeasure Technology for a Cylinder-On-Demand Engine- Development of Active Booming Noise Control System Applying Adaptive Notch Filter

The conventional active noise control technology for engine booming noise¹ based on the Filtered-Reference LMS algorithm ^2,3 has a conflict in between the ability of tracking a change of engine rpm and simultaneously controlling the low frequency (low rpm) region. As a result, the conventional approach is difficult to apply for booming noise for a low rotation engine, an important region for weight reduction of a vehicle. Because of these reasons, there are few applications of the conventional approach to reduce booming noise.

The purpose of this study is to propose a less complex ANC system based on a Single-frequency Adaptive Notch (SAN) ^2,4 algorithm. The system proposed in this paper solves the problem of good control performance in the low rotation or rpm region, assures the stability related to a mass production, and reduces the number of component parts in a manufacturing process. The proposed ANC system includes these technologies and is integrated in an audio system and applied to reduce booming noise in a cabin.

The system developed in this study has been applied in combination with an active control engine mount system. It is applied to a new model vehicle with a V6 engine that provides cylinder on demand. The purpose is to reduce booming noise generated by an engine in three-cylinder operation, resulting in the achievement of excellent fuel economy and NV performance.