The document describes the main components of a gasoline engine, including the cylinder head, cylinder block, crankcase, oil pan, cylinders, pistons, connecting rods, crankshaft, camshaft, intake and exhaust valves, valve springs, injectors, spark plugs, and flywheel. The engine uses the cylinder head and block to contain the cylinders, in which the pistons are connected to the crankshaft by connecting rods and powered by fuel from the injectors ignited by spark plugs to drive the flywheel.