Piston and Piston Rings

Diesel Engine Fundamentals DOE-HDBK-1018/1-93 DIESEL ENGINES In engines using sleeves, there are two Figure 5 Diesel Engine Wet Cylinder Sleeve types of sleeves, wet and dry. A dry sleeve is surrounded by the metal of the block and does not come in direct contact with the engine's coolant (water). A wet sleeve comes in direct contact with the engine's coolant. Figure 5 provides an example of a wet sleeve. The volume enclosed by the sleeve or bore is called the combustion chamber and is the space where the fuel is burned. In either type of cylinder, sleeved or bored, the diameter of the cylinder is called the bore of the engine and is stated in inches. For example, the bore of a 350 cubic inch Chevrolet gasoline engine is 4 inches. Most diesel engines are multi-cylinder engines and typically have their cylinders arranged in one of two ways, an in-line or a "V", although other combinations exits. In an in-line engine, as the name indicates, all the cylinders are in a row. In a "V" type engine the cylinders are arranged in two rows of cylinders set at an angle to each other that align to a common crankshaft. Each group of cylinders making up one side of the "V" is referred to as a bank of cylinders. Figure 6 Piston and Piston Rod Piston and Piston Rings The piston transforms the energy of the expanding gasses into mechanical energy. The piston rides in the cylinder liner or sleeve as shown in Figure 2 and Figure 3. Pistons are commonly made of aluminum or cast iron alloys. To prevent the combustion gasses from bypassing the piston and to keep friction to a minimum, each piston has several metal rings around it, as illustrated by Figure 6. Rev. 0 ME-01 Page 7