The New Valvetrain System of GM / Opel

Authors

J. J. Moon, S. Feldmann, D. Certo, GM Global Propulsion Systems, Pontiac, USA; Dipl.-Ing. L. K. Cloos, Dipl.-Ing. (FH) S. Müller, Opel Automobile GmbH, Rüsselsheim

Year

2018

Print Info

Fortschritt-Berichte VDI, Series 12, No 807

Summary

Variable valvetrain systems represent an important building block for increasing the efficiency of boosted SI-engines. In the area of tension between CO2-emissions on one side and increasing customer’s expectations of drivability and transient response on the other side, variable valvetrain systems enable appropriate operation strategies. Two-step discrete variable systems have successfully been established in the market over the past few years.
At General Motors Global Propulsion Systems, a new tripower multi-discrete-variable valve lift system for future gasoline engine generations has been developed in close cooperation with Opel Automobile GmbH. The core feature of this system is a sliding cam functionality that allows multiple discrete lifts for the intake and exhaust valves. In this paper, the mechanical design of the discrete variable valve lift system will be described with special focus on challenges arising from the multi-discrete variability. The control system including actuators and sensors will be explained to show how this system is implemented. Finally, aspects of the manufacturing process will be presented followed by an evaluation of customer benefits.