Abstract:
Automobile engine Valve actuation is of primary importance in the field of internal combustion engines. The conventional engine uses camshaft for valve operation which can be varied to a certain extent with the engine speed variation. The variable valve timing is an alternative to the conventional camshaft operated engines with the improved valve timing variation. The variable valve timing technology developed cannot provide continuous valve timing variation and resulted in improvement in valve timing variation to a limited scope. The effective alternative to the camshaft engines is camless valve actuation system with the advantage of fully flexible valve timing according to the engine speed variation leading to fuel efficient engine operation. The camless valve actuation systems include electromechanical, hydraulic, piezoelectric, pneumatic and hybrid actuators with combination of actuators. A modified hybrid valve actuator (MHVA) with combined effect of electromagnet and permanent magnet was designed and validated using FEM and prototype testing. A lumped parameter model (LPM) was developed to approximate the experimental and FEM results of MHVA using valid mathematical expressions. The LPM is developed based on the physical parameters identified by curve fitting of experimental force data and mathematical equations representing the coil dynamics, force and armature dynamics of MHVA. The electrical, magnetic and mechanical subsystems are developed in MATLAB and integrated to develop LPM. The results of LPM are compared with the experimental and FEM results to validate the lumped parameter model developed in this study.
