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).
Second report on preliminary rig tests of a combined pump and injector, detailing experiments to reduce pump lag and injection period.
| Identifier | ExFiles\Box 179b\3\ img091 | |
| Date | 1st February 1933 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Ud. c. Eg. c. Nor. M.{Mr Moon / Mr Moore} c. Hy.{Tom Haldenby - Plant Engineer} M.{Mr Moon / Mr Moore} c. Mr. Jaques. Hs{Lord Ernest Hives - Chair}/Ud.6/AM.2.33. X4483. R.R. COMBINED PUMP AND INJECTOR PRELIMINARY RIG TESTS - SECOND REPORT SUMMARY OF REPORT. In the first report (Hs{Lord Ernest Hives - Chair}/Ud.7/KTG.1.33) the development of the pump to give a satisfactory delivery speed characteristic was described. The spray issuing from the injector was next examined and the pump lag and injection period measured by means of an oscilloscope. This at once showed that at 1000 R.P.M. (pump speed) the lag was -14.0° and the injection period 41.5° at normal injection quantity (0.235 ccs/cycle). From fuel-line pressure diagrams taken on the engine with a Farnborough indicator, the injection period was of the order of 15°. Hence the injection period of the R.R. pump was excessive and could not, at this stage, be tried on the engine with any hope of success. This report describes the experiments conducted with the view to reducing both the pump lag and the injection period. By plugging all but one of the suction chamber holes the lag was reduced 2.5° and the injection period to 23° at normal injection. The effect of leaving unplugged different holes was investigated, delivery-speed, pump lag and injection period and sometimes control position delivery curves being taken for a speed range of 340 R.P.M. to 1000 R.P.M. In addition to the above, the following tests were conducted :- (1) The effect of fitting an air vessel in the supply pipe on the delivery-speed curve, pump lag and injection period. (2) Effect of the unloading delivery valve on the above quantities. (3) Comparison of the injection period and pump lag at maximum and normal injection. (4) Comparison of delivery and spill curves at maximum and normal injection. (5) Subsidiary investigations on valve bounce, discontinuous injection, nature of the jet under various conditions, etc. | ||