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).
Testing an S.U. Petrol Pump as fitted to the Phantom III.
| Identifier | ExFiles\Box 149\4\ scan0014 | |
| Date | 2nd October 1936 | |
| To Rm.{William Robotham - Chief Engineer} E Da{Bernard Day - Chassis Design} Ev{Ivan Evernden - coachwork} x1263 Hs{Lord Ernest Hives - Chair}/JBD.{John B. Dixon - Fuel Systems}14/KW.2.10.36. A sketch of the rig should be attached. Report on S.U. Petrol Pump as fitted to the Phantom III. The rig was arranged to reproduce as nearly as possible the actual conditions on the car. The levels of the various parts and lengths of pipe were the same as those in the chassis, with arrangements to maintain them at any desired temperature up to 90°C. The pump and carburetter were mounted in a heated chamber in which circulation of hot air was maintained by a fan. The level of petrol was shown in a gauge glass, and glass tubes fitted in the inlet pipes to the pump and carburetter. It was also possible to draw petrol from the float chamber to represent the petrol consumed by the engine. Tests were carried out to reproduce - (1) The period of starvation when starting up after a 15 minutes stand with a high under-bonnet temperature. (2) The possibility of starvation at high speed. (3) Comparison between pumps and diaphragm materials. After standing 15 minutes with a tank temperature of 32°C., pipe lines at 32°C., and under-bonnet temperatures of 75 & 80°C., it was found that the petrol boiled readily in the pipe between the pump and carburetter, but although it also boiled in the carburetter, the vapour passing up the pipe through the needle valve carried petrol up with it, thereby maintaining the level in the float chamber. This in some cases even caused slight flooding, and in others building up the level until the float needle valve remained closed and there was sufficient pressure generated by the vapour to hold back the diaphragms and stop the pump till the level was lowered and the pressure released. At the higher temperatures the pipe boiled practically dry. | ||