CN code 840820 covers compression-ignition internal combustion piston engines (diesel engines) intended for the propulsion of vehicles of Chapter 87 of the Combined Nomenclature. Chapter 87 encompasses motor cars, tractors, motorcycles and other land vehicles. This subheading includes diesel engines used in passenger cars, vans, trucks, buses, agricultural tractors and special-purpose vehicles. The key criterion distinguishing it from subheading 840810 (marine engines) and 840890 (other) is the intended use in road vehicles of Chapter 87. Cylinder capacity is not a subdivision criterion within heading 8408 at the 6-digit level. Engines may range from approximately 1.5 litres in passenger cars to over 16 litres in heavy trucks. Classification follows the General Rules for the Interpretation of the CN, rules 1 and 6, and the Notes to heading 8408. Import of engines for heavy-duty vehicles represents a significant segment of international trade. Engines for agricultural tractors also fall under this subheading when classified within Chapter 87.

Importing vehicle diesel engines under subheading 840820 into the EU requires compliance with the Union Customs Code and motor vehicle type-approval regulations. Engines for passenger cars and light commercial vehicles must meet the Euro 6e emission standard (Regulation (EU) 2024/1257), covering NOx, particulate matter (PM), particle number (PN) and CO2 limits. Engines for trucks and buses are subject to Euro VI (Regulation (EC) No 595/2009 as amended). Type-approval is issued under Regulation (EU) 2018/858. Importers must hold an EORI number and submit a customs declaration with CN code 840820. Documentation includes a commercial invoice, transport document, engine technical specification with emission data, and type-approval certificate. Engines imported as spare parts do not require separate type-approval but must comply with vehicle manufacturer specifications. REACH applies to substances in engine components. Duty rates and FTA preferences should be verified in TARIC. Import of truck engines from third countries, particularly Turkey and South Korea, is significant in the EU market.

Vehicle diesel engines under subheading 840820 are undergoing significant technological transformation driven by tightening emission standards and EU climate policy. Modern diesel engines feature latest-generation common rail injection systems, variable geometry turbocharging, exhaust gas recirculation (EGR), diesel particulate filters (DPF) and selective catalytic reduction (SCR) systems using AdBlue (DEF). In the passenger car segment, the diesel market share is declining due to urban regulations (low emission zones), fiscal policies and consumer preferences for electrification. In the truck and bus segment, diesel engines remain the dominant propulsion technology, although the share of vehicles running on LNG, CNG and hydrogen is growing. Import of truck diesel engines from third countries, particularly Turkey and South Korea, is significant in the EU market. Preferential rates are available under FTAs with these countries. The aftermarket parts sector for diesel engines remains substantial due to the large fleet of diesel vehicles in operation across the EU.