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).
Fuel system tests involving spray orifices, plunger springs, and throttle movements.
| Identifier | ExFiles\Box 179b\3\ img136 | |
| Date | 3rd August 1933 | |
| -3- Cont'd.{John DeLooze - Company Secretary} SPRING BETWEEN PLUNGER AND SEATING REMOVED. SPRAY ORIFICE .031. Instantaneous full throttle movement is available, owing to the main plunger spring compressing against the fuel, which owing to the restriction of the spraying orifice will supply fuel for 3 1/2 seconds after the full throttle position has been obtained. The fuel lift is 6ft. Fuel is delivered at all movements of the throttle. (6) SAME AS (5) BUT PLUNGER SPRING REDUCED BY 50%. SPRAYING JET .051. Results are similar to (5) except that the fuel is only lifted 3ft. and the supply continues for 11 secs. after the full throttle position has been attained. Fuel is delivered on all throttle movements. The tests were repeated with the spray orifice increased to .062 dia. and shewed similar results but with a greater speed of operation and a less dashpot effect. Summarising the tests with jets in the spray tube have shewn that the initial quantity of fuel delivered is totally inadequate to be of much assistance to any degree of acceleration. The restriction of the jets to the pump is such, as to form a dashpot, which is not desirable owing to the danger of damaging the operating mechanism throughout, unless a very light operating spring is used, and then the fuel supply is lessened due to delayed action in compressing the spring against the fuel. All systems will pump fuel under all conditions and speed of throttle operation, except the system having a light spring holding the plunger off its seating. A further scheme is in hand to reduce the capacity of the pump by 50% and will be tried out as soon as completed. | ||