Adaptation of a Dual Continuous Variable Cam Phasing System to a 4-Valve, 4-Cylinder Engine - Thermodynamic Benefits and Engine Hardware Requirements

The adaptation of a Dual Continuous Variable Cam Phasing (DCVCP) system provides increased volumetric efficiency at wide open throttle (WOT) conditions and considerable potential to minimize fuel consumption by allowing internal exhaust gas recirculation and the associated pumping loss reduction.

To exploit the full benefits of a DCVCP system significant development work has to be carried out to design the airflow path, combustion chamber, the hydraulic system and timing drive.

The selected cam phasing authority of 45 crank degrees on the exhaust VCP and 60 crank degrees on the inlet VCP required attention to the actuation speed and setting accuracy. Particular focus was given to the development of the oil circuit pressure and flow requirements to cover oil temperatures from -30°C up to 140°C, and to the cam drive system for the higher inertia moments.

This paper summarizes the development work to apply a DCVCP system to a new engine variant of an existing engine family with the main focus on the development of the DCVCP subsystem and the airflow and combustion system.