Kinematics analysis and design method of a new mechanical CVVL system with self-regulation of the valve timing

In the present study, the position of the camshaft pivot center is controlled to achieve continuous variable valve events. An innovative mechanical continuous variable valve lift (CVVL) system with self-regulation of the valve timing is proposed in this regard. Based on the system, an effective design method for the profiles of intermediate cam and cam is emphatically presented. After the profiles are determined, the kinematic behavior is calculated through a kinematic model developed in this work and its results are used to verify the appropriateness of the methodology. A prototype is successfully manufactured and tested. The experiment results verify the validity of employed design method and the applicability of the system in gasoline engines. It is found that the valve motions in different lift phases from experiment are in good agreement with those calculated through the kinematic program. Besides, the system is successfully operated up to 6000 r/min engine speed (greater than the rated speed 5500 r/min of the test engine) during the experiment. All these have provided a significant reference for the development of mechanical CVVL systems. (C) 2019 Elsevier Ltd. All rights reserved.