ua 



ALCOHOL FUELS FOR INTERNAL COMBUSTION 



ENGINES. 



By W. Petchell. 



Read July 13, 1921. 



For a long time it has been apparent that the only substitute 

 for petrol for internal combustion engines which could be obtained 

 in unlimited quantities without robbing Nature's resources is 

 alcohol. 



Its disadvantages are its low calorific value and low vapour 

 pressure. 



Its advantages are : — 



It does not carbonize in the cylinder to anything like the 

 extent that petrol does. Sooted-up plugs are practically unknown 

 when running on alcohol fuels. 



Its comparative safety from fire. Burning alcohol can be 

 extinguished easily by water. 



The explosion in the cylinder is not so sudden as with petrol. 

 Pre-ignition under ordinary circumstances will never occur, so 

 that a car can be driven uphill on top gear until the engine almost 

 stops without any of the hammering that occurs with petrol. 



Various methods have been proposed and tried with a view 

 to remedying the disadvantages of alcohol as a fuel. In order to 

 increase the calorific value the addition of benzol, naphthalene, 

 and various other substances has been tried. An excellent mixture 

 is 60% of alcohol and 40% benzol. This mixture gave excellent 

 results, but would not start easily when the engine was cold. This 

 called for a special carburetter or a small quantity of a more 

 volatile fuel for starting purposes. Then the supply of benzol is 

 limited. 



The low vapour pressure and consequent difficulty in starting 

 with alcohol only is a very serious drawback to using it in the 

 engines of motor cars, etc., as the average driver will not go to 

 the trouble of having a second tank fitted and carrying a supply 

 of a fuel which is easy to start up on. To obviate this several 

 methods have been tried, the two most common being the addition 

 of sulphuric ether, and saturating the alcohol with acetylene. 



Some years ago the mixture of acetylene and alcohol was tried 

 in America with a certain amount of success, but was abandoned 

 on account of the then high price of alcohol and low price of 

 petrol. The drawback to this mixture is that it soon gets stale. 

 The calorific value is very slightly improved, as the alcohol will 

 not absorb more than about 0-8% of acetylene by weight. There 

 is also a possibility of the acetylene acting on the copper pipes 

 leading to the carburetter, etc. 



Mixtures of alcohol and ether were proposed and tried several 

 years ago, but until the Natalite patent was applied for there was 

 no proposal to use ether in such large percentages. 



