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).
Continued description of a fuel pump plunger system's operation and comparison with a spring-loaded system.
| Identifier | ExFiles\Box 179b\3\ img008 | |
| Date | 4th January 1933 | |
| -2- He/Pur.7/MA.4.1.33. Cont'd.{John DeLooze - Company Secretary} plunger is grooved on its periphery to form a turbulent pressure to seal the clearance, when the pump is operated sharply. This system also avoids fuel pumping on progressive throttle movement, but is less efficient than the spring loaded plunger scheme in the respect that the distance of plunger travel, and consequently the amount of throttle opening, required to form a seal and give positive pressure, is greater, and therefore does not pump fuel on short "flicks" of the throttle, as when a slight "burst" of engine is required. Generally, the great advantage of the spring loaded system is that on actual acceleration, the leak is definitely sealed, after the plunger has travelled the distance, equivalent to the gap forming the leak, which is actually .015", with the other system, it is obvious that the plunger will have to travel a greater distance to build up the "friction seal" between piston and bore, sufficient to overcome the differential valve pressure. This system also has the disadvantage that if the clearance is reduced to speed up the pressure, then we return to pumping fuel on progressive throttle opening. HE/Pur. | ||