1. Cummins ISX15: This 15-liter inline-six engine is renowned for its ruggedness, reliability, and fuel efficiency. It's widely used in heavy-duty trucks and construction equipment.
2. Detroit DD15: Another excellent heavy-duty engine from Detroit Diesel, the DD15 offers impressive power, torque, and durability. It's commonly found in long-haul trucks and specialized vehicles.
3. Volvo D13: Known for its excellent fuel economy and low emissions, the Volvo D13 is a 13-liter engine that's widely used in medium- and heavy-duty trucks, buses, and marine applications.
4. Mercedes-Benz OM471: This 4.7-liter inline-six engine from Mercedes-Benz is particularly impressive for its compact size and high torque output. It's found in a range of vehicles, including the Mercedes-Benz Sprinter van.
5. Volkswagen EA288: Among smaller Diesel engines, the Volkswagen EA288 stands out for its combination of fuel efficiency, refinement, and performance. It's used in various Volkswagen, Audi, and Skoda models.
Ultimately, the "best" Diesel engine is the one that best meets the specific needs and requirements of the intended application.