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).
Report comparing B.V. and B.11 induction systems to investigate petrol consumption issues.
| Identifier | ExFiles\Box 97\2\ scan0210 | |
| Date | 20th June 1941 | |
| To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} c. to Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} c. to Inr. 400 Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}5/SW.20.6.41. B.V. Carburation. The attached curves represent an analysis of the B.V. induction system compared with the B.11 system on the test bed. The reason for comparing the two systems, was to find the cause for B.V. petrol consumption being worse than B.11. Briefly, results show the cause to be :- The restriction set up by the air silencer system, causes the carburetter air valve to reach the top of its stroke at comparatively low revs, so that above that speed, metering is not controlled. The tests were carried out on a Standard B.V. engine, as follows :- Test No.1 Full throttle, and constant speed throttled curves, on the B.11 pipe with B.11 carbs, but using the B.V. air intake bend and silencer. It will be seen that there is no quarrel with the automatic functioning of these carburetters, compared with the ideal line. Test No.2. Repeat test of No.1., but using the complete B.V. induction system. It will be seen that full throttle metering runs weak at middle speeds, and rich at low speeds (1,500 r.p.m. and lower). It is important to remember that a richer low speed setting has to be used to counteract :- - continued - | ||