MOTORS&MOTORING

Dominion, Volume 10, Issue 3070, 4 May 1917, Page 9

MOTORS&MOTORING

Air-Coolcd Engines. Thore are not a few engineers, says an American writer, who feel that the air-cooled motor is duo for a rejuvenation and further development during the next few years. In the early days of motoring history, the list of air-cool-I ed power plants was almost as long as ! that of water-cooled engines. At tho present time, practically all tho patents covering air-oooled motors have passed iiito the hands of ono company. It would scarcoly be-fair to assume, therefore, that tho type had not proved efficient, when patent difficulties prevent any general manufacture of this claes of power plant. In its favour tho aircooled power plant has the broad principle or thermodynamics, that, other things being equal, the internal comTjustlon engine, .which runs hottest, will bo the most nearly efficient. As a matter of faot, tho only, reason for employing any system of cooling the motoo is simply the inability of the materials of -which it is made to stand more than a certain degreo of heat. A highoylinder temperature resnlts in more perfect combustion through better vaporisation of tho fuel. When water is used as a cooling medium, tho temperature of the outside cylinder wall never gots above 212 degrees. With nircooling, one can safely get a liigher cylinder heat than that. Another advnitage of the air-cooled power plant is the reduction in weight achieved. Kot onif does the water itself add weight .to tbe car, but the jackets necessary to contain it in contact with the cylinder wails are very heavy. Well-designed au--ccoled motors, with fins for carrying asvay the heat, weigh little more than ordinary, cylinders without their heavy water-jackets and fluid. Another development -.favourable to air-cooled motor' practice is found in. the recent rise of aluminium alloys as oylinder matmial. Aluminium, is an excellent conductor of heat^nearly as good as copper. It will be.-.possible to cost aK-cwsleu cylinders of aluminium with radititinpr fins to get rid of tho heat, simply lining them with cast-iron. In ■tiiis'way tho weight of tho rxiwer plant willba cut down to the minimum without loss in the thermal efficiency, which is the air-cooled motor's chief claim to consideration. .