Chapter 18 Development and Application of Dual UniValve System Based on a GDI Engine with SI/HCCI Dual Combustion Modes

摘要

A full-variable-valvetrain prototype named Dual UniValve System has been developed for a GDI engine with SI/HCCI dual combustion modes, improving the fuel economy and emission performance under some of part and low load conditions. Based on the dynamic performance test, reliability of Dual UniValve System has been qualified. In addition, under the NEDC condition, UniValve system can optimize the friction loss significantly. The switching response time between valvelifts of 0-8 mm is only 0.16 s, which provides a fast response for transient conditions. Furthermore, in the engine test with Dual UniValve System, SI/HCCI combustion mode switching has been also achieved with a fast speed, which increased indicated efficiency by 10 % and reduced NO_x emissions by 99 %.