How Diesel Two-Stroke Engines Work

By: Marshall Brain  | 

General Motors EMD Engines

The General Motors EMD engine line is typical of the two-stroke diesel breed. These engines were introduced in the 1930s and power a large number of the diesel locomotives found in the United States. There have been three successive series in the EMD line: the 567 series, the 645 series, and the 710 series. The numbers refer to the number of cubic inches per cylinder, with a typical­ engine having 16 cylinders (for a total displacement on the order of 10,000 cubic inches!). When you consider that a 5-liter (305-cubic-inch) engine is considered to be very large in an automobile, you can see that one of these EMD engines is massive!

Here are some of the specifications for the EMD 645E3 engine:


Cylinder diameter - 9-1/16 inches

Piston stroke - 10 inches

Displacement per cylinder - 654 cubic inches

Number of cylinders - 16 or 20

Compression ratio - 14.5:1

Exhaust valves per cylinder - 4

Engine weight -

  • 16 cylinders: 34,526 pounds / 15,661 kg
  • 20 cylinders: 40,144 pounds / 18,209 kg (The oil pan alone weighs over a ton!)

Idle speed - 315 rotations per minute (rpm)

Full speed - 900 rpm

A typical horsepower rating for one of these engines is 4,300 hp!

For more information on the diesel two-stroke and other engines, check out the links below!

Originally Published: Apr 1, 2000

Diesel Two-stroke Engine FAQ

What is the difference between two-stroke and four-stroke engine?
One big difference between two-stroke and four-stroke engines is the amount of power the engine can produce. A two-stroke engine has the potential to produce twice as much power as a four-stroke engine of the same size.
How does a diesel engine work?
Diesel engines compress only air and then injects the fuel directly into the compressed air.
What are the main parts of two-stroke diesel engine?
Exhaust valve, fuel injector, air intake, piston and crank case are some of the main parts of a two-stroke diesel engine.
Is a diesel engine better than a gas engine?
A diesel two-stroke engine suffers from none of the environmental problems that plague a gasoline two-stroke engine. On the other hand, a diesel two-stroke engine must have a turbocharger or a supercharger, and this means that you will never find a diesel two-stroke on a chain saw — it would simply be too expensive.
What are two-stroke diesel engines used for?
Diesel engine technology is often combined with a two-stroke cycle in the huge diesel engines found in locomotives, large ships and generating facilities.

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