An Innovative Control System for a 2/4 Stroke Switchable Engine 2007-01-1199
The 2/4SIGHT engine concept is based on a novel design of combustion system, which makes use of an electric-hydraulic valvetrain and advanced control technologies, enabling automatically controlled dynamic switching of the engine between two- and four-stroke operations. This concept has the potential to improve fuel consumption by up to 30% compared to a conventional gasoline engine.
A 3 cylinder GDI engine with two stage boosting system and electro-hydraulic valvetrain is the main application for this project, with 6 cylinder application being studied in simulation.
The design of a Control System poses several challenges due to the simultaneous introduction of several innovations such as advanced boost system, electro-hydraulic valvetrain system and two/four stroke operating mode.
In order to develop and optimise the design of the control system, an integrated simulation environment has been developed. This includes the model of the engine operating either in 2 or 4 stroke mode, the model of the innovative boost system, the model of the electro-hydraulic valvetrain system, and the whole control system.
The Engine Control Strategies have been structured into the modules “Operating Mode Supervision”, “Operating Mode Transition Management”, “Air Charge Control and Estimation for 2 and 4 stroke operations” and “Valve Lift Profile Management”.
A dedicated Valve Control Unit (VCU) controls each hydraulic valve; therefore each cylinder can be independently controlled in all the operating conditions (2 stroke, 4 stroke and transitions).
Communication between the Engine Management System and the VCUs is defined by a communication protocol designed and developed to allow fast, safe and reliable operations.