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).
Performance improvements in a compression ignition engine using Bosch nozzles and injectors.
| Identifier | ExFiles\Box 179\3\ img043 | |
| Date | 8th March 1932 | |
| ORIGINAL a.{Mr Adams} From Hm{Capt. W. Hallam - Head Repairs}/CHP. c. to SG.{Arthur F. Sidgreaves - MD} SOT. c. to RS.{Sir Henry Royce's Secretary} E.{Mr Elliott - Chief Engineer} c. to EV.{Ivan Evernden - coachwork} V.W.33. Hm{Capt. W. Hallam - Head Repairs}/CHP.S/MA. 8. 3. 32. COMPRESSION IGNITION ENGINE. A further improvement in the performance of this unit may now be reported: at 2000 R.P.M. a B.M.E.P. of 101.0 lbs/sq.in. has been obtained at a specific consumption of .460 lbs/BHP/HR. (The previous figure, reported 19.1.32, was 97.7 lbs/sq.in. at .473 lbs/BHP/Hr). This improvement in performance has been brought about by the use of nozzles of Bosch manufacture. These nozzles have been drilled to our specification, and they have the same size and number of holes as those previously used. The conditions under which this latest improvement was achieved are rather contradictory to our previous experience, viz:- (a) Standard Bosch pump cam. (b) Standard Bosch 10 m/m dia pump element. (c) Standard Bosch injector and nozzle, having a different- ial ratio of .75. (d) Low injection valve setting of 3000 lbs/sq.in. It will be remembered that our previous improvement was obtained by using amongst other conditions a 25% quicker lift pump cam, a differential ratio of .47, and a valve setting of 5000 lbs/sq.in. Comparing the Bosch injector valve and nozzle with our own latest type we find that :- (a) The weight of the Bosch valve needle and connecting pin is approximately four times as heavy as the corresponding parts of our own valve. (b) The Bosch nozzle is made in one piece with the valve guide, ensuring perfect alignment between valve and seat; whereas our own nozzle is a separate unit. (c) The fuel capacity between the spray holes and the valve seat is reduced to an absolute minimum. | ||