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).
Fuel test results for a Two-litre Sunbeam engine, detailing a specific alcohol-benzol-ether mixture and its properties.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan40 | |
| Date | 27th January 1926 guessed | |
| -7- Two-litre Sunbeam - contd :- FUEL TESTS. Tests carried out with various fuels and mixtures show that the best results were obtained with a mixture containing :- Methyl Alcohol 50% by vol. Benzol 33% " " Ether 17% " " The methyl alcohol was used to take advantage of the large fall in temperature due to latent heat of evaporation making it possible to get an increased weight of charge into the engine at a lower temperature. The benzol was used to give the mixture a good toluene value and counteract the bad effects of the ether, which was used to give easy starting. Ricardo's figure for fall in temperature of the air-fuel mixture due to latent heat of evaporation of methyl-alcohol is 140°C, the figure for ethyl-alcohol being 85°C. For the methyl-alcohol, benzol and ether mixture, this temperature drop works out at 64°C and with the substitution of ethyl alcohol for methyl alcohol in the same percentage, the temperature drops was estimated to 48°C - compared with petrol 20°C. The specific gravity of the methyl mixture (Sunbeam 2 on the graph) is 0.864 which means that with a theoretical air-fuel ratio of 9.55/1 by weight for complete combustion, there would be an increase of weight of fuel to be carried of 60% for a given mileage. The figure for the ethyl mixture (Sunbeam 1 in the graph) with a specific gravity of 0.822 - air-fuel ratio 10.95/1 by weight, is a 39% increase in the weight of fuel to be carried. Hs{Lord Ernest Hives - Chair}/V.Halliwell. | ||