THE DIESEL ENGINE

Hawera Star, Volume L, 14 February 1931, Page 13

THE DIESEL ENGINE

PROGRESS AT HOME

HEAVY TRANSPORT WORK. Gradually but sureiv progress is being made with the development oi the automobile heavy oil engine, and right throughout the leading countries of the world interest is being displayed in the future of this type of engine, which is fraught with great potentialities. A few years ago experts were not aptimistic as to the early application of the liiesel principle engine to road transport use, but rapid advance has been made and now t.io world appears to be on the eve or the appearance of the heavy oil engine as a serious competitor to the present-day peirui engine. 60 satisfied are some of the leading English manufacturers ol heavy ser. ice truck and bus cimssis tl.at production on a fairly large scale has already been started. ror bus and other heavy load transport work, it is claimed, startling savings will be effected in fuel consumption. It should be noted that the Diesel type engine as applied to the motor is not a crude oil engine, as the Diesel properly is, but an oti-shoot of the Diesel. “From the investigations we have .so far made, the author lias no doubt that the list of objections which have been generally cited as rendering the heavy-oil engine unsuitable for application to in-town bus service is by no means inslrmountaole. . . There

are already a number of compressionignition engines in use on service vehicles in England to-day, which the author understands are putting up a satisfactory performance. The outstanding advantages of the heavv-oil engine are so great that every encouragement should be given to the development of this form of prime mover. ’ ’

These remarks were made by -Mr. George J. Shave, chief engineer to the London General Omnibus Co., Ltd., in the course of a very interesting paper which he read before a. joint meeting of the Institute of Automobile Engineers and the Institute of Transport in London.

In view of the considerable publicity which has recently been given to the tests which this company have made of the new British A.E.C. compres-sion-ignition engine, Mr. Shave’s views are of more than ordinary interest.

Many speakers at the meeting, incidentally, emphasised the unsuitability of the term “Diesel” for these modern high-speed oil engines, which are much lighter in proportion to their power output than any power unit which the great Doctor Diesel ever conceived. The phrase “compression-ignition” engine is perhaps clumsy .but it is very apt, as it is the outstanding feature of these engines that the firing of the fuel is obtained solely from the compression and heating of air. The A.E.C. engine, incidentally, is of the six-cylinder type with a bore and stroke of 110 mm. and 142 mm. iespectively; it develops over 100 b.li.p. at 2500 r.p.m., and has actually' a maximum speed of 3000 r.p.m. Not long ago designers were struggling to reach 2000 r.p.m. with this type of engine.

According to Mr. Shave, the early difficulty of obtaining a low idling speed without excessive fumes or smoke has been overcome, so that the engine

in question will “run light” at 300 r.p.m. without becoming in any way objectionable. The main advantage gained by adopting this typ.e of engine in place of the petrol engine are, according to Mr. Shave, the low cost of fuel, the greatly increased mileage per gallon (about double that obtained on petrol) and the reduction of fire risk to negligible proportions. He also suggested that every endeavour should be made to use home-produced gas oil, so securing the additional advantage of burning British fuel. Many well-known engineers .spoke in the ensuing discussion, notably Colonel ft. E. Crompton, who said. “In my opinion the use of compression-ignition engines will eventually extend to private cars, although perhaps they will be amongst the last vehicles to lie so powered.’ .Mr. Alorland. from considerable ex|>( rieuco running goods vehicles with oil engines, said that he thought that these power units required still further refinement before they could safely be used in congested eilv areas.