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).
Description of a fuel pump's operation, its features, and the faults of alternative fuel systems.
| Identifier | ExFiles\Box 27a\2\ Scan010 | |
| Date | 12th August 1926 guessed | |
| AC SPARK PLUG COMPANY #604 By revolving shaft (G) the eccentric (H) will lift rocker arm (D) which is pivoted at (E) and which pulls linkage (F) together with diaphragm (A) held between metal discs (B) downward against spring pressure (C) thus creating a vacuum in pump chamber (M). Fuel from the rear tank will enter at (J) through strainer (K) and suction valve (L) into pump chamber (M). On the return stroke spring pressure (C) pushes diaphragm (A) upward forcing fuel from chamber (M) through pressure valve (N) and opening (O) into the carburetor. When carburetor bowl is filled the float in the float chamber will shut off the inlet needle valve, thus creating a pressure in pump chamber (M). This pressure will force diaphragm (A) downward against the spring pressure (C) where it will remain in the downward position until the carburetor requires further fuel and the needle valve opens. Spring (P) is merely for the purpose of keeping operating lever (D) in constant contact with eccentric (H) to eliminate noise. 3. AC FEATURES 1. Noiseless operation. 2. Gives good idling. 3. Gasoline and air is fed to the engine only through the carburetor. 4. Fuel is fed to the carburetor directly in proportion to the requirements of the engine. 5. A sufficient supply of fuel is assured to meet all conditions of speed, loads and grades. 6. It is built in as an integral part of the engine, much in the same manner as the oil pump. 7. It permits the chassis to be entirely independent of the body. 8. It makes a cleaner engine appearance and saves the limited space under the hood for new devices, which are quite essential, such as air cleaners, oil filters, etc. 9. It is very quickly primed even at very low speeds due to its extremely large capacity (about 16 to 18 gallons at 300 R.P.M. engine speed). 10. The pressure on the carburetor is low (3/4 to 1 lb per square inch and can be varied at will). 4. FAULTS OF OTHER FUEL SYSTEMS (A) Vacuum Tank The vacuum tank, which is being extensively used today as a fuel feed system, is far from being satisfactory, and following are some of the disadvantages which are recognized. | ||