Reduction of three-cylinder engine vehicle vibrations by use of switchable mounts

One of the main issues of NVH for three cylinder engines, in particular without balancing shaft, is that the frequencies of the vibrations are shifted within the range of suspended powertrain resonances (rigid powertrain on the stiffness of the mounting system) at idle and low rpm speeds. In order to improve the idle vibration comfort with removing the balancing shaft, one or two electrical switchable mounts can be used to tune the modal behavior of the powertrain and thus to decrease the level of vibration in idle and in driving conditions A switchable mount is an hydro mount with an electrical (or pneumatic) actuator which permits to modify the dynamic stiffness and damping of the mount by switching from one internal hydraulic behavior to another.