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A novel mechanism using a moving rocker pivot has been developed by Motive Engineering. The chosen approach offers variation of lift, duration, and phase. A compact, robust proof-of-concept mechanism has been designed, and fabricated. It was fitted to the intake valvetrain of a production SOHC four-cylinder engine. The operation of the mechanism is described. A longer-duration, higher-lift camshaft was designed to explore the potential benefits of the concept throughout the speed and load range. Dynamometer testing has been done to explore possible benefits to power, fuel economy, and exhaust emissions.

Race engine development is a complex multidimensional problem with a large number of interacting parameters. The competitiveness of the engine requires that this set of parameters be fully optimized, and the inevitable limitations of program budget require that this complex optimization task be done quickly and cost-effectively. What is described here is a methodology that has been developed as an addition to traditional techniques; to speed the development process by the use of power development knowledge and computer aided tools. A sound physical model of the engine is manipulated by the use of design of experiment (DOE) tools, and the repetitious iteration of all the calibration parameters is automated This allows for an optimized solution to be converged upon without analyzing every possible combination of parameters.