From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article clipping from 'The Autocar' discussing the possibilities of using alcohol as a fuel for engines.
| Identifier | ExFiles\Box 32\1\ Scan029 | |
| Date | 8th November 1913 | |
| THE AUTOCAR, November 8th, 1913 993 The Possibilities of Alcohol Fuel 150 mm., and with such valve openings and lifts as enabled 2,000 r.p.m. to be easily attained. In these experiments, using a Claudel-Hobson carburetter, with only such adjustments as could be got by altering the size of the jet and the air inlet, there were obtained slightly higher powers from alcohol mixtures at anything up to 2,000 r.p.m. than from the same engine running on petrol. The consumption experiments were only carried out with half and half mixture of alcohol and benzole, and in the time at Dr. Ormandy's disposal he could not repeat the whole of the work carried out by Messrs. Craig and Napier on the Maudslay. What results he did get, however, are enough to show that, even with the much higher piston speed of the Sunbeam engine, with the slight increase in actual compression obtained under the new working conditions, it was possible to get an explosive mixture which would burn rapidly enough to develop at least as much power as petrol in an engine having a piston velocity of about 2,000 feet per minute. By supplying the engine with fuel through a flexible pipe from a weighed fuel container, Dr. Ormandy got the actual time employed in burning 1 lb. of fuel, and from this he calculated that the thermal efficiency at 1,400 r.p.m. was 22.6%, and that the "percentage charge" was 72% compared with only 55% in the Maudslay engine. "Percentage charge" is, of course, the amount of mixture actually entering the cylinder per stroke, expressed as a percentage of that theoretically possible. A slightly richer mixture and a slightly higher compression enabled this result to be sustained from 1,100 up to 2,000 r.p.m. The results obtained bear out the contention that economy will arise from the weakest possible mixture which will burn with the required velocity. It is an advantage of alcohol that its combustible range in admixture with air is greater than that of petrol, because it enables us to retain the best available compression by simply weakening the mixture. As the modern petrol engine runs for most of its time much below its rated capacity, it follows that on alcohol mixtures the engine should be running most of its time within that portion of its speed range where the thermal efficiency is greatest. Conclusions. The main conclusions to be drawn from the experiments here summarised are. (1.) That an ordinary modern petrol engine will run on a half and half mixture of benzole and alcohol, and give just as much excellence in its more important working qualities as when running on petrol. (2.) That variation of compression has a much greater influence on the success of alcohol than has hitherto been suspected, and this points to the necessity for scientific investigation on carburation with a view to more perfect gasification and reduction of throttling. (3.) That the contention urged by Dr. Ormandy that progress towards the final goal of using alcohol virtually as a sole fuel is best sought by experimenting on mixtures containing gradually diminishing amounts of benzole, and that all the known data, properly attested, point to the fact that it is only a question of intelligent research to reduce the amount of benzole to a negligible quantity in proportion to the alcohol. | ||