Performance Evaluation of a Camless Engine Using Valve Actuators with Programmable Timing

An electronic valve timing (EVT) approach is described which utilizes high-speed, electropneumatic actuators producing nearly square wave valve lift profiles throughout the nominal engine speed range. The resulting impact on engine “breathing” combined with the controllability afforded by totally programmable valve timing produce an engine with performance capability radically different from any traditional internal combustion engine. A comparison test was conducted on a 1.9 liter, four-cylinder engine to investigate the effects of these unconventional valve dynamics. The primary focus of this paper is the presentation and discussion of the results of this evaluation.