Determination of optimum location of active tuned mass dampers to obtain improved NVH performance during cylinder de-activation events

Cylinder deactivation has been a proven technique to improve fuel economy for several years now. But on the flip side during cylinder deactivation events, high amplitude torque pulsations are generated at the crankshaft of the engine over a wide frequency range creating a potential risk for NVH performance of the vehicle. As passive tuned mass dampers are effective only in a narrow frequency range, active tuned mass dampers (ATMD) have become a popular choice to mitigate the risk. Often, engineers rely on finite element (FE) models of vehicle structures to make design decisions during the early stages of vehicle development. However, there is relatively little literature available on simulation of ATMD using FE techniques. Consequently, in most cases, ATMDs are not included in the FE models of vehicle structures. Several details related to the ATMD design are decided through physical testing at the latter stages of vehicle development. To address this issue, a methodology to simulate an ATMD during cylinder deactivation events using FE technique is presented here. In this paper, after demonstrating that an ATMD can improve acoustic responses in vehicle during cylinder de-activation events, the mass and location of the ATMDs are optimized such that an improved NVH performance is obtained at the driver’s touch points.