# New Actuation Control for Hybrid Electromagnetic Valve Train
## 1 Introduction  
The global warming issue is significantly increasing, the Arctic ice layer is gradually melting, and, hence, the sea level is rising. The reason for this is that humankind has no restraint in the use of energy, and the number of cars in the world grows year by year. Improving the efficiency of internal combustion engines has become one of the mainstreams to overcome this problem. There are many ways to improve the efficiency of internal combustion engines. Among them, variable valve timing (VVT) and variable valve lift (VVL) techniques are effective options to improve engine efficiency [1]. Especially, the intake for a camless engine purely depends on valve actuation. The energy consumption of internal combustion engines can be reduced by using active valve trains such as electromagnetic, electronic-hydraulic, electronic motor valve trains, etc. [2]. These can reduce engine consumption by 15% and reduce exhaust emissions by 20%. Several automobile firms have presented their devices with their technologies. The electro-mechanical-based VANUS from BMW [3], the hydraulic-based VTEC from Honda [4], Shiao's magnetorheological valve train [5], and the electro-hydraulic-based VarioCam from Porche [6] are successful examples. Among the existing active valve trains, the electro-mechanical valve drive (EMVD) [7, 8] is the conventional one, which gives variable valve actuation with an electrical motor and mechanical linkage. This linkage uses nonlinear conversion to convert the rotary motion into reciprocating motion, so that the valve can be opened and closed, and the engine canachieve variable valve timing during operation to improve engine efficiency. However, due to the complexity of the mechanism and the larger size of the motor, the size of the engine will increase. Moreover, the motor needs to be continuously supplied with power, which requires high total energy consumption. Second, the electro-hydraulic valve actuator [9; 10] mechanism uses a servo-motor-based switch to control the hydraulic circuit of the valve mechanism. This switch-controlled hydraulic circuit can precisely control the opening and closing of the valve, so that the engine can achieve variable valve timing and variable valve lift when the engine is running. This effectively improves engine efficiency. However, the overall mechanism is more complicated: it still needs to cooperate with the hydraulic system, and the servo valve is continuously energized, which requires high energy consumption, so there are concerns about leakage of the hydraulic system. Moreover, the electronic control has a faster response than the electric-hydraulic or electro-mechanical control. Then, electronically controllable electromagnetic valves (EMV) [11; 12; 13] were introduced for valve actuation. They are constructed with a set of electromagnet coils on the upper and lower sides of the armature. The coils can be energized to generate magnetic force, and the armature in the middle is attracted to move up and down by electromagnetism, to control the opening and closing of the valve, so that the engine can achieve variable valve lift and timing actively during different loads and speed conditions. The EMV has advantages such as compact design, accurate control, and quick response. However, like other active valve systems, EMV also consumes energy for the actuation of the electromagnets. Therefore, a design of permanent magnet-based EMV has been developed to reduce the energy consumption of the EMV. In addition to retaining the original electromagnet, these valve mechanisms [14; 15] also have permanent magnets (PM), so that this PM force can hold the valve during the valve closed position. [PERSON] [16] suggested a new compact electromagnetic engine valve, with the design of dual permanent magnets, and performed software analysis and optimization on the mechanism. It relies on the magneto force of the permanent magnet to keep the valve closed.