Conception, modélisation et dimensionnement d'un système de levé de soupape à trois positions discrètes pour un moteur essence automobile

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Abstract : As the constraint on vehicle consumption tightens, variable valve lift strategies are used to increase engines efficiency. This thesis focuses on issues related to the design of a three-stage electromagnetic valve tappet. First of all, the tappet has to fit inside the engine and has to offer three different valve lifts: a full lift for high speed and torque requirements, a low lift for small loads and a lift allowing cylinder deactivation for medium loads. The tappet dimensioning includes, for example, cams feasibility, spring parameters and contact pressure between cams and tappets. Valve lift selection is made by two electromagnetic actuators in order to obtain a short transition time. Their size, however, hinders their integration. Hence, we realize an optimization aiming to reduce its volume and define the command profile and its return springs. This optimization requires a multi-physics model (electric, magnetic and dynamic) to simulate the actuator behavior. Due to the

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