PETROL v. CRUDE OIL

Timaru Herald, Volume CXXXIV, Issue 18849, 11 April 1931, Page 14

PETROL v. CRUDE OIL

AX OLD QUESTION DISCUSSED. Recently there have appeared in the New Zealand press various references to the above subject, including cabled extracts from English newspapers, giving the impression that tremendous improvements had taken place in the so-called semi-Diesel type cf internal combustion engines. A New Zealand engineer, who is an authority on the subject, states that the general trend of this information would lead the public to assume that the day of the petrol engine was past, an assumption that is not warranted by the facts. “In the first place.” he says, “there is no question that a great deal of attention has been devoted to the possibilities of such development, and I thing I am right in saying that there is no large firm manufacturing motor vehicles which has not gone into the matter more or less deeply.” Cost of Fuel. The main, in fact almost the only, virtue claimed for the semi-Diesel type is the lower cost of fuel due to the type of fuel burnt. This claim is based largely on the decreased fuel consumption per mile. Certainly the cost of crude oil per gallon is less than that of petrol, but it is extremely likely that this will be only a temporary measure. Once the use of such a type of engine spreads to an extent, one may be sure that excise duties would be imposed on the crude oil to make up for the loss of revenue consequent on the cessation of the use of petrol. Wear and Tear. Due to the nature of a compression ignition type of engine, the explosion stresses are very heavy, consequently this engine must be made heavier, and naturally dearer. Wear and tear is increased, but the greatest objection is that the cost of a typical heavy commercial vehicle, engined by the type now under discussion, would be between £3OO and £4OO more in England than that of a corresponding petrol driven vehicle. Convenience of Running;. Again, due to the nature of such a type of engine in which ignition is due to heat consequent on high pressure in the cylinder, it is at the moment extremely difficult, in fact impossible, to produce an engine which will idle reasonably slow; consequently, this type of engine is noisy and its life is diminished. “Summed up then,” says our informant. “I would say that the present position is, that while no progressive manufacturer would overlook the possibilities of such a design, yet he would require to be able to assure his customers that any new design should be as least as cheap, as reliable, as longlived, and as certain to obtain service in the many directions required by a modern vehicle as the type which is supplanted. “The customer from his point of view would require to be dissatisfied with the extent of being willing to pay, say 30 per cent, more for its successor, with the doubtful advantages just mentioned included. “It can safely be said that neither the manufacturer nor the customer is at present in this position.”