Divided by purpose: diesel engines for construction machinery, diesel engines for agricultural machinery, diesel engines for underground equipment, diesel engines for vehicles, diesel engines for forklifts, diesel engines for compressors, generator sets, welding machines, pump diesel engines, diesel engines for power generation, marine diesel engines.
Divided by displacement and number of cylinders: single-cylinder diesel engines and multi-cylinder diesel engines.
Divided by operating cycle: two-stroke diesel engines and four-stroke diesel engines.
Other classifications include: vertical, horizontal, inline, inclined, V-shaped, X-shaped, W-shaped, opposed cylinders, opposed pistons, etc.
