This paper presents a model of an electric variable valve timing (EVVT) system and its closed-loop control design with experimental validation. The studied EVVT uses a planetary gear system to control the engine cam timing. The main motivation of utilizing the EVVT system is its fast response time and the accurate timing control capability. This is critical for the combustion mode transition co...

In an effort to reduce dependence on petroleum-based fuels and increase engine efficiency, fuel-flexible engines with advanced technologies, including variable valve timing, are being developed. Fuel-flexible spark-ignition engines permit the increased use of ethanol–gasoline blends. Ethanol, an alternative to petroleum-based gasoline, is a renewable fuel, which has the added advantage of impro...

This paper presents a detailed model of a novel electropneumatic valve actuator for both engine intake and exhaust valves. The valve actuator’s main function is to provide variable valve timing and variable lift capabilities in an internal combustion engine. The pneumatic actuation is used to open the valve and the hydraulic latch mechanism is used to hold the valve open and to reduce valve sea...