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).
Proposal for a petrol gauge that measures the fuel level based on air pressure differentials.
| Identifier | ExFiles\Box 75\2\ scan0113 | |
| Date | 28th January 1920 | |
| X.3891. Extract from R1/G28.1.20. X.3882. RE PETROL GAUGE ETC. ON THE FUEL TANK OF CAR. X.3891. A long time ago I heard of a suggestion of telling the amount of petrol in the back tank by the difference of air pressure required to make air enter the tank below the level of the liquid. I shew you in the attached sketch, my modification of this idea, the principle of which is well known, and I am not sure that the application would be found suitable, but I should be pleased if you would make a few experiments to find if it would give any useful results. | ||