A team at the University of Waterloo has developed a novel variable valve actuation (VVA) system, optimized to pursue minimum energy consumption and minimum sensitivity of the valve lift to cycle-to-cycle variations of engine pressure. The product of a decade of research, this patented system could improve fuel efficiency by more than 10%, said Amir Khajepour, a professor of mechanical and mechatronics engineering at Waterloo. The new VVA system, described in a paper in the journal Mechatronics , uses an energy recovery technique to remove the trade-off that exists between the system’s power consumption and sensitivity. The results show that the optimized system has a low variability of about 5% (0.5 mm) to cycle-to-cycle variations of 50% in the in-cylinder gas force. The optimized VVA with the proposed energy recovery system (ERS) also consumes about 58% of the energy used in a conventional cam-driven valvetrain. In general, VVA systems […]