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).
Data table and analysis of injection periods and pump lag at different engine speeds.
| Identifier | ExFiles\Box 179b\3\ img099 | |
| Date | 1st February 1933 | |
| -9- TABLE 3. Posn. of hole. | Fig. NO. | Pump Lag (º) Normal | Injection Period (º) Normal Injection | Pump Lag plus Injcn Period | Static Injcn Period (º) Normal | Varn. in lag for speed range 336 RPM. to 1000 RPM. --- | --- | --- | --- | --- | --- | --- 1000 R.P.M. 6 holes | 4 | -14 | 41.5 | - | 19º | 16 No. 1 open | 7 | 2.5 | 23.0 | 25.5 | 19 | 3.5 " 2 " | 16 | 3.0 | 23.0 | 26.0 | 19 | 2.5 " 3 " | 9 | 3.0 | 24.75 | 27.75 | 19 | 3.0 " 4 " | 18 | 3.0 | 24.5 | 27.5 | 19 | 3.5 Nos. 2 & 5* | 16 | 1.0 | 25.5 | 26.5 | 19 | 4.5 336 R.P.M. 6 holes | | +2 | 19.5 | 21.5 | 19 No. 1 open | | 6 | -16.0 | 22.0 | 19 " 2 " | | 5.5 | 14.5 | 20.0 | 19 " 3 " | | 6 | 17.0 | 23.0 | 19 " 4 " | | 6.5 | 16.5 | 23.0 | 19 Nos. 2 & 5* | | 5.5 | 15.0 | 20.5 | 19 INJECTION PERIOD. The injection period curves are shown on Figs. 4, 7, 9, 16 and 18. These all show the characteristic of increase in injection period with speed. With 6 holes unplugged the increase of injection period over the speed range is 22º. With 2 holes unplugged the increase is 10.5º and with one hole unplugged the increase is about 8º. Hence the best characteristic is again given by a single suction chamber hole. The injection periods for 1000 R.P.M. and 336 R.P.M. are set out in Table 3. Since the pump lag is the angular interval between sealing of the suction port and the first appearance of the spray at the nozzle, adding the injection period to the pump lag gives the angular interval between the sealing of suction port and the end of injection. | ||