FUEL ENERGY.

Northern Advocate, 28 May 1921, Page 1

FUEL ENERGY.

"To-dny evprv iiu-uns oi' increasing the efficiency ol" tlio petrol engine, and so obtaining move work lor Ilie expenditure of tlio same aniouiil of fuel do-crv-os attention, snvs the, ''Autocar 1 ' (Eng.)- The cost of motoring, like that of everything else, is inflated, and any way of reducing it is to be welcomed. With the present type of engine lea-* tlmn a third part of the energy contained in the fuel used is converted into useful woik; a third part goes to the exhaust, while the remaining third par 4' is carried nway in the form of heat given to the cooling water. The wttstc of power- is therefore great, and until an engine with a higher efficiency than that of the four-stroke cycle is adopted the best that enn be done is to decrease waste as much as possible bv attention to minor sources of losv of power. On preenit-day car engines one of these minor sources of' loss occurs in the amount of heat carried away by the engine; cooling-water, which in nearly every east is greater under normal running condition'-* tliun it need be. Obviously this must be so when the radiator nntt cooling system have been designed to carry away the heat developed when the engine is run at full power. For the larger portion of its time the ear engine is only called upon to .deliver a fraction of it? full power, an (Joinder such circumstances,, a temperature .controlling device is fitted, too much heat will be given to the cooling water. Experiments on the test bench have proved -that, the most economical running is obtained when the cooling water i* kept at about 180 degrees P., and the results at this, temperature are from 5 to 10 per cent, better than those obtained at a empcratur.t of 50 degrees lower. The gain in the case of the car on the road would not be as much as this, since the engine is. not mnning under full power. It would, nevertheless, be sufficient to make the fittings of a regulating device well worth while. Such regulating device may be divided into two classes, those operated by hand and 4 hose operated automatically by means of a thermostat. These two methods of operation may, in most cases, be applied to the various systems in use for temperature regulation. One of the simplest of such systems i-'. to place shutters of Venetian blind pattern in front or behind the radiator with a thermometer to indicate the engine temperature to the driver. These shutter-, may be operated through a positive hand control. In some mikes of ear the fan drive is controlled so that its speed may be varied to suit atmospheric conditions'; again in others the fan can be put out of ac-tion by means of a clutch.