The Progress of
Page 57
If you've noticed an error in this article please click here to report it so we can fix it.
THE HEAVY OIL ENGINE
Extracts from a Paper by Mr. W. Vane Morland, A.M.I.Mech.E., M.I.A.E., M.Inst.T.
THOUSANDS of users throughout the country are displaying considerable interest in the developmeut of the heavy-oil engine for use in commercial, chassis. Censenuently, the paper read by Mr. W. Vane Renaud, A.M.I.Mech.E., M.I.A.E., Minst.T., at Harrogate, last Thursday, during the 29th Annual Conference of the Municipal Tramways and Transport Association, was of particular value, especially as Mr. Vane Morland has had a long experience of municipal-transport services, being general Manager and engineer to the tramway motor seevices of the County Borough of Walsall.
The paper commenced with a short history of the petrol engine, and it is mentioned that Britain has definitely ousted the remainder of t'ue world in the provision of roadtransport services, and now at a time when it had begun to appear that no more radical changes could be expected history is again repeating itself, and the Diesel engine is entering the field of road-transport services to compete with the petrol engine.
Fuel Costs of a Diesel=engined Double-decker.
In 1929 the author had reported to the municipal-. transport general managers at their annual meeting at Portsmouth that the data available indicated that the fuel cost of operating a double-deck bus in this country, with an engine of the Mercedes-Benz pattern, would be approximately a half-penny per bus-mile, and subsequent practical experiments by Sheffield and Walsall have proved this calculation to be correct.
The Gardner engine, as used by Walsall, Sheffield and Leeds. is a high-speed, compression-ignition engine of British manufacture, the governor cutting down the speed to approximately 1,350 r.p.m.
Some startlingfigures regarding possible savings in fuel are instanced. With a fleet of 100 single-deck buses having heavy-oil engines, the fuel saving is estimated to be 117,500 per annum, of which 16,250 is represented by the saving in taxation. The consumption of lubricating oil is also superior to that of a petrol engine, and the quality remains good for a long period, .both these points being due to the lower working temperature.
The fire risk hn vehicles on the road and in confined spaces is reduced to the minimum, as the flash-point of the fuel is about 170 degrees F. It is said that a vehicle with a Gardner engine can be
driven away from the garage immediately it is started, no warming-up process being required. It can be.Ieft-running idle for any length of time and the exhaust does not become smoky, whilst for a given power only about 50 per cent. by volume of fuel is required, as compared with the average petrol engine.
The power unit giving more complete combustion must of necessity liberate less deleterious gases in its exhaust, both on account of the smaller fuel consumption and the more complete burning. The odour from a Diesel-engine exhaust is generally less objectionable than is the case with a petrol engine when the latter is using low-grade petrol.
A.E.C. Production Plans.
• The statement is made that the Associated Equipment Co., Ltd., is so satisfied with its extensive endurance tests of engines built by it, and utilizing the Bosch-Acro system, that the company has been justified in putting the first 100 oil-engiued vehicles into production for imniediate sale to transport users. The author recently tested one of these vehicles carrying a load of 61 tons, and a speed of over 40 m.p.h. was attained. In the Acro system, one portion of the combustion chamber is directly in connection with the cylinder bore; the other part is contained in a separate chamber or cell in the cylinder head and connected to the first part by a short restricted passage. The compression ratio employed is 15.5 to 1, as compared with about 5 to 1 for a petrol engine. Practically no fuel is burnt within the air cell, almost all the combustion occurring in the main chamber which connects directly with the cylinder. Electrically heated plugs are Provided for starting the engine from dead cold, the crankshaft being rotated in the usual way by an electric motor.
The A.E.C.-Acro engine is stated to have a speed range of 800 to 3,000 r.p.m., the maximum power being obtained at about 2,500 r.p.m., when 100 b.h.p. has been attained. An illustration of this engine is published on page 198.
The author states that with a fleet of 100 double-deck buses using fuel at 4d. per gallon, the saving in fuel costs alone would be 122,000 per annum. He points out that he does not wish to create the impression that the stage of development which has been reached entitles local authorities or the larger bus companies immediately to press manufacturers for the delivery of large fleets of oil-engined buses for inter-town or city services. The latest types of petrolengined bus have reviled an exceedingly high stage of refinement, and any attempt to intliet on the public a vehicle in any way inferior would be strongly resented. The conditions obtaining in the operation of motorbuses in heavy-trafficked routes are such as to require a highly efficient and refined vehicle, and the heavy-oil engine is not yet at that stage.
There is a danger that hostile' criticism may strangle the use of these engines for passenger work and so retard normaldevelopment and progress. They should be given a sufficiently lengthy trial in the road-haulage Industry and in long-distance motor coach or country motorbus services, and experimentally by local. authorities. 'Whatever may be the future of the electric tratectir or the trolley-bus, he says, .few will be disposed to deny that the internal-combustion-engined vehicle is destined to find an ever-increasing use in the municipal passenger-transport systems both at home and abroad. •It remains to be seen how far local authorities and the road-transport industry generally support the motor manufacturer in this country in the development of the Diesel -engine.
ANOTHER INTERESTING PAPER
Another paper of interest to road-transport users• was that read by Councillor A. LI: Gledhill, chairman of the tramways and inotorbuS committee of Halifax Corporation, his subject -being " The' transition in road passenger -trans• • port, with special reference to the changes that have taken place between 1928 and 1930."
He dealt with the history of travel -by road and the development of the hackney carriage, and proceeded with • statistics of the numbers of vehicles licensed and the 'receipts from. such licences and from the petrol tax,., showing the relationship between these receipts and' the cost of highway mainteiranne, which, for 1930, he put at 156,000,000. The receipts under, the two ,above-mentioned heads he put at 139,500,000, and he contended that the tendency of the past few years to place an excessive burden upon one industry by increasing the tax on hackney carriages and by re-introducing the petrol tax was unjustified. .
He pointed out, however, that over 180,000,000 has been invested in tramways and 11,222,581,206 in railways, and said 'that it would be a national disaster if unrestricted competition :rendered this capital_ unremmierative.
He then leak at somt+ length with the effect of special Acts of Parliament which have been obtained to protect tramway and other interest's, and stated that in the past two years the railway companies have acquired a part interest in 14,000 ..big motor conches out of about 63,000 public-service vehicles. They have, he said, expended /7,590,000 in obtaining shares in road-transport under
takings.
He then dealt in detail with the subject of operating costs, concluding with s reference to the new competitor in the form of the oil-engined passenger vehicle.