Advanced diesel engines fuel many of the world’s most vital industries. Boats, barges, and semis move most products that consumers use every day. Agricultural equipment ensures we have the food and natural resources we need. Construction equipment powers our infrastructure.

WHAT ARE THE TWO TYPES OF DIESEL ENGINES?

There are a number of different ways to classify diesel engines. Commonly, they are categorized by how much power they can output (small, medium, and large). However, another way to distinguish between them is by looking at the number of strokes (2-stroke engines and 4-stroke engines) used to complete an engine cycle. As you might guess, 2-stroke engines use two strokes while 4-stroke engines use four.  Let’s take a closer look at each of the two types of diesel engines:

• 2-Stroke Diesel Engine: 2-stroke engines provide a complete engine cycle in just two strokes. Essentially, as the cycle begins, air enters the cylinder, dispelling any old air. Then, the compression process occurs. As the piston nears the top of the cylinder, diesel fuel is added, producing chemical energy. That energy pushes the piston down, sending mechanical energy to the wheels.
  • 2-stroke diesel engines are generally the lighter and smaller of the two types. However, only operating on two strokes means it is more susceptible to wear and tear, which is one of the reasons 2-stroke engines are less common.
• 4-Stroke Diesel Engine: In a 4-stroke engine, the pistons move up and down twice—for a total of four strokes. In addition to the compression and exhaust strokes (described above), the pistons also have return strokes. Essentially, the process begins with drawing the air into the cylinder as the piston moves down. As the piston moves up, the air is compressed. Once the piston reaches the top of the cylinder, the fuel is injected, causing the ignition. Upon ignition, the piston is pushed down, and the mechanical energy is released to the wheels. Finally, the piston moves back up to dispel the burnt gasses.
  • • 4-stroke engines are the most common variety, used in most diesel trucks and automobiles.