Dual Fuel Injection + Center Injection
GDi (Gasoline Direct injection) and MPi (Multi-Port injection) each has its pros and cons. GDi applies compressed fuel directly to the cylinder, and its precision of injection provides high power output and good fuel economy at low engine load. The cons are noise and vibration at relatively low speeds and, because the fuel might not mix well with the air, relatively high emissions of PM matter. Compared to GDi, MPi is freer from noise and vibration concerns, but it is generally worse in power output and fuel economy.
Hyundai Motor Group’s new Dual Fuel Injection system comes with two injectors, one GDi and the other MPi, for each cylinder, taking advantage of the pros of both injector types. For low-to-mid speed everyday driving, the system uses the MPi injector; for high-speed driving in highways or expressways, the system uses the GDi injector. Such optimization of fuel injection type to the driving conditions has led to an improvement in both performance and fuel economy.
Moreover, in an arrangement called Center Injection, the GDi injector has been moved to the center of the combustion chamber to produce the optimally efficient air/fuel ratio. The injector at the center is now closer to the spark plug, which allows it to particularize its injection strategies. For example, injecting a tiny amount of fuel near the spark plug right before the ignition can instantaneously facilitate the mixing of the air/fuel in the chamber and best achieve the optimal desired air/fuel ratio.
This, in turn, leads to faster combustion that contributes to improved performance and fuel economy. Finally, the injector being placed at the center better allows for symmetrical injection patterns that help reduce the amount of wall wetting (the phenomenon in which the fuel adheres to the chamber walls).
*Models with Dual Fuel Injection: Smartstream G2.5 GDi / T-GDi
*Models with Dual Fuel Injection + Center Injection: Smartstream G3.5 GDi / T-GDi
High Tumble Combustion System (HTCS)