Analysis of the nonlinear dynamics of a double magnet electromechanical valve actuator (EMVA)

To meet future requirements on automotive systems in terms of increase engine power, while reducing fuel consumption and pollutant emissions, new camless engine must be designed. One of the most appealing way is to develop an independent valve actuator system able to realize Variable Valve Actuation (VVA) operations. To this aim, a promising solution relies on Electromechanical Valve Actuators (EMVA) technology, where an electronic control system commands each valve properly at every engine speed. The effectiveness of the EMVA system depends on the performances of the control strategies necessary to guarantee the first lift manoeuver (named first catching) and precise valve closing/opening with a fast and soft valve seating (Soflanding control). The control must account for the behavior of the system which is strongly affected by many nonlinearities such as friction (with non smooth effects), impacting phenomena (due to motion constraints) and the presence of strong nonlinearities on magnetic force. Mathematically, the system can be described as a piecewise smooth mechanical oscillator actuated by a nonlinear magnetic force.