Equipment Operator, Basic

CHAPTER 1 ENGINE SYSTEMS

To become a professional Equipment Operator, you must understand the principles of operation of automotive and construction equipment. This chapter covers the basic principles of engines, fuel systems, air induction systems, lubrication systems, and cooling systems on the equipment used by the Navy and the Naval Construction Force (NCF).

INTERNAL COMBUSTION ENGINES

An engine is a device that converts heat energy into mechanical energy to perform work. An internal combustion engine is any engine in which fuel is burned within its body (fig. 1-1). The combustion that occurs within the cylinders produces energy. This energy moves the parts of the engine that drives the equipment.

Figure 1-1.-Basic elements of an engine.

Air and fuel are two elements needed to produce heat energy in an engine. Oxygen in the air is evenly mixed with the fuel and is vaporized. This mixture allows for quick and even burning. The chemical process that occurs when the air and fuel mixture in the cylinder is ignited is known as combustion.

An engine uses both reciprocating motion and rotary motion to transmit energy. Four parts of the engine work together to convert reciprocating motion into rotary motion. These four parts are as follows: a cylinder, a piston, a connecting rod, and a crankshaft (fig. 1-2). The piston and cylinder are matched parts, fitted closely to allow the piston to glide easily with little clearance at the sides within the cylinder. The top of the cylinder is closed and has a space for the combustion chamber. The connecting rod transmits the up-and-down motion of the piston to the crankshaft. The crankshaft

Figure 1-2.-Piston and crankshaft.

Figure 1-3.-Piston to crankshaft relationship.

Figure 1-4.-Piston positions.

has a section offset from the center line of the shaft so that it "cranks" when the shaft is turned (fig. 1-3).