Diesel Engines

Sun (Auckland), Volume II, Issue 528, 4 December 1928, Page 7

Diesel Engines

loin' Cost and Simplicity May Menace Petrol . Though its shadow on the motor wo rld is now little bigger than a man’s finger-nail, the Diesel engine •nay yet supplant the present type 0 f motor in both cars and airplanes. honS used in stationary and marine r j CS( tho Diesel has been exploited by several makers of heavy trucks in Geriu^n y, and has proved successful. Similar engines are about to be manufactured for tho same purpose in America. Because it uses oil fuel, the Diesel engine operates at about one-fifth the cost of the petrol-driven motor. The great bulk necessary to get a requisite

power output previously hampered its adaptation to the requirements of road vehicles, but recent discoveries have shown how to overcome this trouble. Unliko petrol-driven engines, Diesels have no carburetter and no ignition system. They may even dispense with a gear set. HOW IT WORKS Briefly, the operating principle is this: When the intake valve '.pens, a charge of pure air is drawn in and compressed to about 3501 b. This compression heats the air to a temperature of several hundred degrees. Just before the piston reaches the top of the compression stroke a measured drop of fuel is pumped into the cylinder at high pressure and tremendous velocity. It almost immediately vaporises and mixes with the hot air, which ignites it, so that the carburetter is replaced by a fuel pump, and compressed air provides ignition.