MOTOR OIL FUEL

Evening Star, Issue 19275, 14 June 1926, Page 6

MOTOR OIL FUEL

PECULIAR CONDITIONS STUDIED DIESEL ENGINES FOR CARS Conditions peculiar to this country in regard to fuels for motor cars, aeroplanes, tractors, and Diesel engines are being studied at present by Mr N. Mitchell, A.M.1.E.E., a research engineer of considerable standing in England. Ho is on a visit to Dunedin, and is representing the British Oil Company, Ltd.: (the Shell Company). With an output in excess of 100,000,000 barrels of oil annually it is essential that the distribution of fuel for all classes of engines and motor-driven vehicles should be controlled by a staff of experts. The company has realised, thatj and Mr Mitchell has been commissioned to investigate the conditions in the dominions. He recently spent two months in Australia.

Mr Mitchell has made a special study of fuel oils, and has also collaborated with Mr H. Ricardo, the famous designer and constructor of motor engines of different kinds. He remarked today to a ‘ Star ’ reporter on tho fact that tractors and nearly all internal combustion engines which used kerosene were, as a rule, working on a relatively low compression ratio in the cylinders. This, lie said, had resulted from the fact that the design of the majority of the tractors produced in tho past had been governed by such kerosene as was available. This, however, was not economical. Light kerosenes were available, but better results could be obtained from a kerosene which permitted a higher compression and increased efficiency.

In liis opinion the Diesel engine would eventually lie installed in motor cars, stated Mr Mitchell. This engine had an extraordinarily high compression ratio, and the injection of oil into air compressed as high as 5001 b, or even. 6001 b, to the square inch caused spontaneous ignition. Diesel engines, having no sparking plugs or electrical installation for ignition purposes, wore, therefore, considerably more economical than tho standard typo of internal combustion motor, and another advantage was that they burned a cheap, heavy oil fuel. Improvements could be expected which would reduce the present great weight of tho Diesel engine and make it practicable for motor cars. Mr Mitchell also referred to the successes of Mr Ricardo in the improvement of motors for “tanks.” By the incorporation of tho Ricardo “ turbulent head,” Ricardo was able to make a. higher compression engine, and thereby double the power output from an engine of the same dimensions. This achievement also removed the old type tank’s disability of emitting great clouds of exhaust smoke when tho throttle was opened up after the engine had “ idled ” for some time, thus revealing its locality to the enemy.