Chapter 22. -DIESEL AND GASOLINE ENGINES 



THERMOMETER- 



- OVERBOARD DISCHARGE 



RESTRICTION 



PRESSURE 

 GAGE 



SEA WATER INTAKE THRU 

 HULL FITTING AND STRAINER 



75.209X 



Figure 22-28.— Salt water circuit of a closed cooling system. 



engine be kept free from abrasion and that there 

 be a minimum of friction and wear. If sliding 

 contact is made by two dry metal surfaces 

 under pressure, excessive friction, heat, and 

 wear result. Friction, heat, and wear can be 

 greatly reduced if metal -to-metal contact is 

 prevented by keeping a clean film of lubricant 

 between the metal surfaces. 



Lubrication and the system which supplies 

 lubricating oil to engine parts that involve slid- 

 ing or rolling contact are as important to suc- 

 cessful engine operation as air, fuel, and heat 

 are to combustion. It is important not only that 

 the proper type of lubricant be used, but also 

 that the lubricant be supplied to the engine parts 

 in the proper quantities, at the proper tempera- 

 ture, and that provisions be made to remove 

 any impurities which enter the system. The 

 engine lubricating oil system is designed to 

 fulfill the above requirements. 



The lubricating system of an engine may be 

 thought of as consisting of two main divisions, 

 that external to the engine and that within the 

 engine. The internal division, or engine part, 

 of the system consists principally of passages 

 and piping; the external part of the system 

 includes several components which aid in sup- 

 plying the oil in the proper quantity, at the 



proper temperature, and free of impurities. In 

 order to meet these requirements, the lubri- 

 cating systems of many engines include, external 

 to the engine, such parts as tanks and sumps, 

 pumps, coolers, strainers and filters, and puri- 

 fiers. These parts and their relative location 

 for one type of engine are shown in figure 22-29. 

 The engine system which supplies the oil 

 required to perform the functions of lubrication 

 is of the pressure type in practically all modern 

 internal combustion engines. Even though many 

 variations exist in the details of engine lubri- 

 cating systems, the parts of such a system and 

 its operation are basically the same, whether 

 the system is in a diesel or a gasoline engine. 

 Any variance between the systems of the two 

 types of engines is generally due to differences 

 in engine design and in opinions of manufacturers 

 as to the best location of the component parts of 

 the system. In many cases, similar types of 

 components are used in the systems of diesel 

 and gasoline engines. 



TRANSMISSION OF ENGINE POWER 



The fundamental characteristics of an in- 

 ternal combustion engine make it necessary, 

 in many cases, for the drive mechanism to 



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