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Recently, control of the gas-exchange process has come into focus as a critical element of the development process for internal combustion (IC) engines. The information learned in various engine development organizations worldwide has recently been put into practice via the introduction of many variable valve control strategies. The intention of these strategies ranges from simple enhancement of volumetric efficiency to completely controlling the combustion process at various engine speeds. The challenge to engine designers is mainly to reduce the relatively high masses of the valve actuating elements while increasing the stiffness to positively affect the dynamic behavior of the valve actuation system. Other benefits of a light-weight valve train is the reduction of the required energy to displace the valve element, which results in a more compact (lighter) cylinder head construction.

The current Brazilian tax legislation promotes vehicles, powered by engines with up to 1.0l displacement. In order to offer the customer an engine with the maximum tax advantage, a supercharged derivative of the Ford 1.0l Zetec RoCam engine was developed. The market specific boundary conditions in South America require powertrains with immediate response especially at low engine speeds. This can be achieved by a supercharged engine concept. The paper discusses the required engine modifications for the supercharger application. The combustion system was changed to benefit from the higher volumetric efficiency, including the optimisation of the intake, exhaust and bypass control system. Extensive modifications of the base engine were required to adapt the engine to the higher thermal load and the specific boundary condition of a supercharger application.

In this paper we describe the application of optimization techniques to the design of valvetrains in high revving internal combustion engines. The methods presented are based on parameter optimization [1] and the minimum principle by Pontrjagin [2] and will be applied to cam lobe and valve spring optimization, aiming at reducing oscillation amplitudes and improving control of the valvetrain over a broad speed range. To put the task of optimization into context the engineering requirements for valvetrains and methods to allow their computer based analysis are described. Furthermore principle considerations for valve event curve generation and parametrization, and on optimization techniques are discussed. Based on these fundamentals, optimization aims and constraints are formulated. Furthermore different examples of the application of automated optimization are presented in the area of cam profile optimization and valve spring optimization.