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).
Potential causes of rich mixture in the vacuum feed tank and requesting data for a new design.
| Identifier | ExFiles\Box 56\1\ Scan004 | |
| Date | 11th August 1925 | |
| X5510 To Hs.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} DA{Bernard Day - Chassis Design}3/M11.8.25. RE. VACUUM FEED TANK. X.8510 X.5510 Mr. Royce is very interested in the problem of the vacuum tank. Have you any more information you can send us? IF the cause of the interference with slow running is liquid petrol being splashed up and finding its way down the suction pipe this does not seem a very difficult thing to deal with. Presumably it takes place at the moment when the float tank is nearly full. There is another possible source of rich mixture, and that is, just after the float tank has been emptied the air valve is shut and the suction valve is open. There is now a considerable quantity of highly carburated air to draw into the engine in the process of re-establishing the vacuum. If this is the cause of the rich mixture it is a rather more difficult thing to deal with, though there are several suggestions that could be investigated. It would be interesting to know for instance whether if pure air were substituted for the carburated air, it upset the mixture to any appreciable extent. This could probably be done by isolating the suction in various ways. In any case it would be of much interest to us to know whether you have discovered the exact cause, and the precise moment when the over-rich mixture is produced. We should like Mr. Royce to design our own vacuum feed system, and in order to do so it is desirable to have as much data as possible. DA.{Bernard Day - Chassis Design} | ||