Abstract
Keywords - Variable Valve Actuation, SI Engine, Fuel Economy, Clean Emission, High Performance
The most important proposition for sustainable mobility consists in dramatically improving the environmental impact, especially by reducing CO2 emissions, which cause global warming. This aim can be achieved by saving energy, i.e. good fuel economy as well as cleaner emissions. On the other hand, customer´s demand for higher dynamic performance is becoming ever more crucial and widespread providing thus more appeal to the product. Nissan has recently developed a new variable valve event and lift (VVEL) system that continuously controls both the intake valve lift and the event angles (or duration, valve opening and closing timing) over a wide range. Combined with the conventional VTC technology, this VVEL system optimally controls the intake valve timing and lift for matching engine operating conditions. This technical specification enables thus to achieve well-balanced improvement for major performance of engines, which are fuel economy, clean emission and high performance. This paper describes various variable valve system effects on engine performance, firstly. And then, the basic configuration of the VVEL system, its actuator system, its electrical control system and specific features of VVEL link mechanism. Moreover, it also explains the design definition and commonaization for the applying expansion from V6 to V8. Finally, the VVEL´s effects for improving the overall engine performance is introduced.