Conception of an indirectly controlled servo valve for IC engine valve position control

The exhaust emissions legislation for motor vehicles with combustion engines is complicating the manufacturing of environmental yet powerful engines more than ever before. Common approaches towards solving this problem from manufacturer side are downsizing, hybridization and the development of electric drives. The subject of this project is the development of an innovative mechatronic control unit as replacement for the camshaft driven valve train of common combustion engines. The systems aim is a contribution to the progression of the development of modern combustion engines satisfying current demands in terms of economy and efficiency. To accomplish this aim, the “Full Variable Valve Train” (FVVT) utilizes an indirectly controlled servo valve, controlling the position of the engine valves fully independently. The advantage of the indirect system control is an enhanced robustness against interference influences. Further, the physical dimensions of the system become smaller, which is a prerequisite in order to implement the system into conventional combustion engines. This paper outlines the basic principles of the system introducing all required components, followed by the layout of the indirectly controlled mechatronic engine valve controller using mathematical fundamentals and fluid mechanics.