61 Copyright Goodheart-Willcox Co., Inc. After studying this chapter, you will be able to: • Explain the operating principles and interaction of the major diesel engine components, such as the cylinder block, cylinder head, valve train, and accessory items. • Explain the difference between two-stroke cycle and four-stroke cycle diesel engines and describe what happens during each piston stroke in both types. • Explain the basics of both two-cycle and four- cycle valve timing. • Define the most popular diesel engine configurations. • Name the two types of combustion chamber designs. • Explain the difference between direct and indi- rect fuel injection. • List the functions of the fuel injection system and name the five types of fuel injection systems used in modern diesel engines. • Explain the basic engine performance terms and formulas, such as bore, stroke, compression ratio, volumetric efficiency, horsepower, and torque. Principles of Engine Operation Technical Terms after bottom dead center (ABDC) air box atmospheric pressure before bottom dead center (BBDC) after top dead center (ATDC) before top dead center (BTDC) bore bottom dead center (BDC) brake horsepower (bhp) cam followers camshaft charge air cooler clearance volume companion cylinders compression ratio compression stroke connecting rod connecting rod journals crankcase crankshaft crosshead cylinder block cylinder displacement cylinder head cylinder liners direct injection combustion chamber distributor pump systems double-acting piston engine engine displacement exhaust manifold exhaust ports exhaust stroke exhaust valves flywheel flywheel housing four-stroke cycle engine fuel injection system governor head gasket head group horizontally-opposed engine horsepower indicated horsepower (ihp) individual pump system inline engines intake manifold intake ports intake stroke intake valves internal engine balancer journals main bearing journals mean effective pressure (MEP) mechanical efficiency multiple-plunger, inline pump system oil galleries oil pan oil pickup tube oil seals piston piston pin piston rings power stroke precombustion chamber pressure pressure-time injection system (PT system) push rods push tubes rated horsepower Chapter 4