8408.20.10.40 - Not exceeding 37.3 kW

This HTS category, 8408.20.10.40, specifically covers compression-ignition internal combustion piston engines, commonly known as diesel or semi-diesel engines, that are designed for installation in tractors intended for agricultural use and have a power output not exceeding 37.3 kW (approximately 50 horsepower). These engines are characterized by their combustion process, which relies on compression to ignite fuel without the need for a spark plug. Their primary application is to provide motive power for tractors specifically engineered for agricultural tasks, such as plowing, tilling, harvesting, and hauling.

This classification distinguishes itself from its sibling category, 8408.20.10.80, which encompasses similar compression-ignition engines for agricultural tractors but *exceeding* 37.3 kW. The key differentiator is the specified power output threshold. Engines classified under 8408.20.10.40 are therefore generally smaller or less powerful units, typically found in compact tractors or those designed for lighter agricultural operations.

As this is a leaf node in the HTS structure, there are no further subcategories under 8408.20.10.40. Classification at this level is determined by the engine type (compression-ignition), its intended application (propulsion of agricultural tractors), and its power rating (not exceeding 37.3 kW). Proper identification of these criteria is crucial for accurate customs declaration and duty assessment.