LO 7-1 Identify and describe the purpose, operating, and regulatory factors influencing cylinder component design and construction

What Are Cylinder Components?

Cylinder components are the engine components first used to convert combustion forces into mechanical power, which makes them a logical starting point to examine diesel engine construction Figure 1. Cylinder components include pistons, piston rings, piston pins (also called wrist pins ), piston pin bushings, and connecting rods (also called con-rods ) Figure 2. These components convert and transfer combustion forces to the crankshaft. They are also the most highly stressed parts of the diesel engine. Flame temperature of diesel fuel is over 3900° F (2149° C), and cylinder pressures can now exceed 3000 pounds per square inch (psi; 20,684 kilopascals [kPa]) of force. Because of these stresses, the design, construction, and operation of cylinder components are critically important to engine performance and durability. In addition, cylinder components (together with other engine systems) are used to reach emissions targets. Design updates and new construction techniques (necessary to meet regulatory standards) mean that cylinder components in contemporary diesels have undergone numerous refinements to help meet higher standards for performance, life expectancy, and low emissions output. Major engine repairs and rebuilding involve replacing or determining the serviceability (remaining service life) of these parts, so technicians need to familiarize themselves with the construction, operating principles, and failure modes of these parts. Engine failures often involve damage to cylinder components; therefore, analyzing failure modes is an important skill to identify and correct root causes of damage to these components. To maintain an engine’s compliance with regulatory standards, technicians should also familiarize themselves with emissions-related features to make correct service recommendations and follow best service practices.

FIGURE 07-1: Cylinder components are used to convert combustion forces into mechanical energy.

FIGURE 07-2: Cylinder components of a diesel engine.