Ultra-ean combustion mode Under most normal driving conditions, up to speeds of 120 km/h, the Mitsubishi GDI engine operates in ultra-lean combustion mode, resulting in less fuel consumption. In this mode, fuel injection occurs at the latter stage of the compression stroke and ignition occurs at an ultra-lean air-fuel ratio of 30: 40(35: 55, including EGR) Superior Output Mode When the gDI engine is operating with higher loads or at higher speeds, fuel injection takes place during the intake stroke. This optimizes combustion by ensuring a homogeneous cooler air-fuel mixture which minimizes the possibility of engine knocking These two modes are represented in Figure 4-1. The piston of the gDI engine is shown in Figure 4-2Ultra-lean Combustion Mode Under most normal driving conditions, up to speeds of 120 km/h, the Mitsubishi GDI engine operates in ultra-lean combustion mode, resulting in less fuel consumption. In this mode, fuel injection occurs at the latter stage of the compression stroke and ignition occurs at an ultra-lean air-fuel ratio of 30: 40 (35:55, including EGR). Superior Output Mode When the GDI engine is operating with higher loads or at higher speeds, fuel injection takes place during the intake stroke. This optimizes combustion by ensuring a homogeneous, cooler air-fuel mixture which minimizes the possibility of engine knocking. These two modes are represented in Figure 4-1. The piston of the GDI engine is shown in Figure 4-2