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Both the automotive and truck industry are facing further regulated emissions legislation in the near future. Understanding the emissions and fuel consumption attributes of an engine/vehicle application during a drive cycle early in an engine development program is a critical step to steer the engine development program to a successful final product. The generally accepted approach is to calibrate an engine on a dynamometer and to adjust the operation of the engine to meet performance targets. With the current build and test approach, these adjustments may not be made until well into the development program, and this calibration is a costly and time consuming step in the engine development process.

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.