Actuator Control for a New Hybrid Electromagnetic Valvetrain in Spark Ignition Engines

Valve timings of a spark ignition engine have been limited to a narrow range of alternatives within the constraints of the fuel economy, the emissions and the dynamic performance. Variable valve timing shows promise as a new key technology for improving the fuel consumption and emissions of spark ignition engines. Several techniques have been developed to perform variable valve timing, and the method with the most potential, called a hybrid electromagnetic valvetrain actuator, is an electromagnetic valvetrain with a permanent magnet and electromagnetic coils installed together. In this study, a novel hybrid electromagnetic valvetrain with a permanent magnet and electromagnetic coils, which significantly differs from existing electromagnetic valvetrains, was designed to overcome the drawbacks of conventional electromagnetic valvetrains that have been introduced previously. This new hybrid electromagnetic valvetrain is characterized by a simple structure, simple actuation and an ultra-low actuating power. Magnetic simulation was applied to analyze the magnetic flux density of the electromagnetic valvetrain and to optimize the design parameters. Dynamic simulation results show that the proposed hybrid electromagnetic valvetrain with soft-landing control can fully satisfy the valve dynamics in spark ignition engines. Additionally, the utilization of a permanent magnet and an optimal actuating current to catch and release valves has many advantages in energy consumption for valve catching and releasing when compared with other electromagnetic valvetrains.