ATAC and GDI in a Small Two-Stroke Engine

In two-stroke S.I. engines, direct fuel injection prevents fuel short-circuiting from the exhaust port, however it does not solve per se combustion problems at light loads due to excessive ratio of residual-to-fresh gas. These problems can be solved by ATAC (Active Thermo Atmosphere Combustion), since residual-gas thermal energy is used to prime the combustion of fresh gas. Experimental results of a small two-stroke S.I. engine with medium-pressure air-assisted fuel injection, operating on ATAC at light loads are shown and prove the possibility to combine the two solutions.