Principles of naval engineering - Historic Naval Ships Association

Chapter 22. -DIESEL AND GASOLINE ENGINESUPPER BEARINGSHELLNUMBER 10MAIN BEARINGLOWER BEARINGSHELLFRAME TOBASE BOLT^icating oil;tion outlet|0N SYSTEMOUTLETBASESHIMSSTUD NUTMOATING OIL)ER INLETLUBRICATIBYPASSLTRATiONSYSTEM INLETFigure 22-13.— Engine base.75.20Xthe engine. However, in some engines, the oilreservoir may be located at some point relativelyremote from the engine; such engines may be referredto as dry sump engines.In the engine base shown in figure 22-13,oil sump is an integral part of the base or crankcase,which has functions other than just beingan oil reservoir. Many of the smaller engines donot have a separate base or crankcase; instead,they have an oil pan, which is secured directlyto the bottom of the block. In most cases, an oilpan serves only as the lower portion of the crankshafthousing and as the oil reservoir.Some engines have flat steel plates attachedto each end of the cylinder block. End platesadd rigidity to the block and provide a surfaceto which may be bolted housings for such partsas gears, blowers, pumps, and generators.Many engines, especially the larger ones,have access openings in some part of the engineframe. (See fig. 22-11.) These openings permitaccess to the cylinder liners, main and connectingrod bearings, injector control shafts.and various other internal engine parts. Accessdoors (sometimes called covers or plates ) forthe openings are usually secured with handwheelor nut-operated clamps and are fitted withgaskets to keep dirt and foreign material out ofthe engine's interior.The cylinder assembly completes the structuralframework of an engine. As one of the mainstationary parts of an engine, the cylinder assembly,along with various related workingparts, serves to confine and release the gases.For the purpose of this discussion, the cylinderassembly will be considered as consisting of thehead, the liner, the studs, and the gasket. (Seefig. 22-14.)The design of the parts of the cylinder assemblyvaries considerably from one type ofengine to another. Regardless of differences indesign, however, the basic components of allcylinder assemblies function, along with relatedmoving parts, to provide a gas- and liquid-tightspace.559