Abstract
This paper describes the design process and simulation results of a variable valve actuation system modeled after the cogging-torque-assisted motor drive (CTAMD) found in literature. Unlike the CTAMD, the new design is capable of handling large exhaust pressures. Furthermore, the new design incorporates damper windings to improve upon the CTAMD by enabling self-starting. The new variable valve actuator is designed for the 6-cylinder Westport 15L diesel engine. The simulated results suggest that the new variation of the CTAMD can be effectively applied to a turbocharged heavy-duty diesel engine.
Simulation results show that the designed motor is capable of self-starting, and infinitely variable lifts. The damper windings are shown to be more beneficial at enabling self-starting and infinitely variable lifts than a spring, since they do not impose additional energy requirements during a valve transition. Furthermore, the new design is also shown to be capable of actuating exhaust valves in the presence of cylinder pressures up to 16 bar with similar efficiency to that of a standard camshaft valve train.
