The present disclosure provides an internal combustion engine (10) having an engine housing (12) with at least one cylinder (14, 114) that has diameter less than about 3 inches. A fuel injector (16, 116) is provided and disposed at least partially within the at least one cylinder (14, 114), and includes a plurality of outlet orifices (22, 122, 124) having a diameter between about 50 microns and about 125 microns, or about.05 millimeters and about.125 millimeters. The injector (16, 116) may include more than one set of separately controllable fuel outlet orifices (122, 124), at least one of which could have an average diameter between about.05 millimeters and about.125 millimeters. The disclosure further provides a method of operating an internal combustion engine (10). The method includes the steps of rotating an engine crank shaft (30) of the engine (10) at a speed greater than about 5000 revolutions per minute, injecting a quantity of fuel into each of the cylinders (14, 114), and burning at least every fourth piston stroke a sufficient quantity of the injected fuel to yield a brake mean effective pressure of at least about 200 lbs. per square inch.