Abstract
Tumble Generation Valve (TGV) is possible to improve combustion stability under lean condition by inclining the tumble rotating axis. This was discussed in the authors' previous works (1-2). TGV can also reduce the level of unburned hydrocarbons produced during a cold start significantly. It seems to play a role in permitting only small fuel droplets to flow into a cylinder, so that the evaporation process increases. Authors named this phenomenon "Preferential Fuel Component Dynamics". Additionally, TGV can reduce the amount of fuel required for the engine to start.
