. Automotive industries . The advantages due to thelight weight and high heat conductivity of aluminumhave long been realized, and aluminum pistons have beenused with considerable success by many casting in permanent molds, the development of asuitable alloy, the heat treatment of the castings are alldevelopments of aluminum pistons of several years stand-ing. The one objectionable feature which has at timesmade trouble in the operation of aluminum pistons hasbeen the fact that it was necessary to run them with agreater clearance than was the case with the cast ironpiston. Th
. Automotive industries . The advantages due to thelight weight and high heat conductivity of aluminumhave long been realized, and aluminum pistons have beenused with considerable success by many casting in permanent molds, the development of asuitable alloy, the heat treatment of the castings are alldevelopments of aluminum pistons of several years stand-ing. The one objectionable feature which has at timesmade trouble in the operation of aluminum pistons hasbeen the fact that it was necessary to run them with agreater clearance than was the case with the cast ironpiston. This was due to the greater coefficient of expan-sion of aluminum as compared with cast iron. In orderto insure the best operation of an aluminum piston it isnecessary that the skirt be fitted with as close a clearanceas possible. The clearance of the ring lands makes verylittle difference as long as it is sufficient to prevent themfrom touching the walls of the cylinder. Recent experiments have proven that the temperature. . .018 to u .016 Io Z .014 w .012 z < .010 < u .008 . CYLINDER DIAMETER INCHES of an aluminum piston skirt is not high enough to accountfor the amount of clearance which it has been necessaryto give these pistons in the past. The head temperature,on the other hand, is much higher than that of the expansion of the skirt may be divided into two parts:(1) the thermal expansion, that is, the increase in sizedue to the increase in temperature of the skirt; (2) themechanical expansion due to the thermal expansion of thehead, that is, the head being so much hotter than theskirt expands more, and this sets up a sufficient force topull the skirt with it. It would be ideal to entirely sep-arate the head from the skirt. Since this is not possiblethe next best thing to do is to separate the head from theskirt on the thrust faces only, and take care of the expan-sion in the direction of the pin by making use of a verti-cal slot or by r
Size: 1877px × 1331px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectaeronautics, bookyear
