DIESEL ENGINES.

Auckland Star, Volume LXIII, Issue 282, 28 November 1932, Page 14

DIESEL ENGINES.

You have published in your news ! column that an engine of the Diesel type is producing 1700 liorse-power at a cost of Sd per hour. The following figures will show you how impossible it is to obtain such a condition. Take crude oil at 2d per gallon. This would give 4 gallons per hour. Specific gravity of crude oil is, on an average, 81b per gallon, giving us 321b of crude oil per hour. One pound of crude oil contains approximately 20,000 b.t.u.'s. We therefore get 640,000 b.t.u.'s per hour. Divide this by 3000 seconds in an hour, we get 178 b.t.u.'s per second fed to the engine. Each b.t.u. contains 1.41 horsepower, so we have 251 horse-power per second delivered, out of which- the engine is getting 1700 horse-power, or an engine of over COO per cent efficiency, or over 500 per cent .more than is fed. Your statement as published is therefore incorrect. The saving in fuel is not so much in the efficiency of : the engine as in the use of a gas engine - to replace steam, which gives only 15 per cent efficiency, whereas a Diesel-will give 32 per cent efficiency, thereby cutting the fuel cost in half, and «it is this factor in making a Diesel available for a railway engine that brings about tho revolution in fuel consumption. ' C. PHILLIPS.