Electromagnetic linear actuators, as key executive components, have a vital impact on the performance of fully flexible variable valve trains. Considering that the conventional moving coil electromagnetic linear actuator (MCELA) has the disadvantages of low force density and a lack of end-passive self-holding ability, a novel composited electromagnetic linear actuator (CELA) is proposed by combining the performance advantages of MCELA and moving iron electromagnetic linear actuator (MIELA) in this work. Firstly, the structure and magnetic circuit design scheme of the proposed actuator are introduced and the finite element simulation model is established. The magnetic field distribution and force characteristics of the actuators are assessed by finite element simulation. Secondly, the construction of the prototype of the actuator is outlined, based on which the feasibility of the design scheme and the steady-state performance of the actuator are verified. Finally, the coordinated control strategy is proposed to realize the multi motion coordination control of the actuator. The research results show that the maximum starting force of the CELA with the end-passive self-holding ability is 574.92 N while the holding force can approach 229.25 N. Moreover, the CELA is proven to have excellent dynamic characteristics and control precision under different motion modes and to have an improved adaptability to the complex working conditions of internal combustion engines.

The variable valve mechanism, as a critical component for the efficient and low-carbon development of internal combustion engines, faces increasingly stringent requirements regarding its driving efficiency, output force, precision, and energy consumption. To address the limitations of existing technologies, a new composite electromagnetic valve train is proposed, characterized by a high force-to-power ratio, fast response, and high precision, along with a unique single/double drive mode, which offers greater flexibility in controlling valve timing parameters; however, it also introduces complex coupling relationships and increases the difficulty of optimization design. To this end, this paper establishes a thermodynamic model of the engine based on the composite electromagnetic valve mechanism. First, it analyzes the effects of different valve timing parameters and drive modes on engine performance; second, a multi-objective game theory optimization algorithm is employed to optimize the valve timing parameters and obtain the optimal solution set; finally, taking into account the energy consumption of the valve mechanism, engine emissions, and performance, a control strategy for valve timing parameters is developed based on an entropy-weighted method combined with a superiority and inferiority solution distance analysis. The results indicated that, under all the operating conditions of the engine, the average torque increased by 2.56%, the effective fuel consumption rate decreased by 6.23%, and nitrogen oxide emissions reduced by 9.86%. Meanwhile, an efficient and economical operational mode for the variable valve mechanism was obtained, providing new insights for the development of variable valve timing technology.