An engine having improved combustion characteristics is provided. The engine includes a fuel injection system that is variable between two operational states. In the first operating state, the fuel injectors provide a fuel spray having first spray pattern characteristics. When the system detects that an operation characteristic exceeds a threshold, the fuel injectors are displaced into a second operating state. In the second operating state, the fuel injectors provide a spray pattern having first spray pattern characteristics. The combustion cycle may be characterized by timing the fuel injection so that the fuel is sprayed into the cylinder early in the compression stroke. Further still, the combustion cycle may be characterized by controlling the fuel pressure so that the fuel pressure is inversely related to the load on the engine.