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).
Benefits of engine valve overlap and separate throttle valves for each induction pipe.
| Identifier | ExFiles\Box 143\3\ scan0176 | |
| Date | 15th April 1940 | |
| Rm{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation} from Rm.{William Robotham - Chief Engineer} 1204 Rm.{William Robotham - Chief Engineer}10/ML.15.4.40. With reference to the attached paper by C.F.Bachle rather an interesting point is raised with regard to the benefits of overlap. It is pointed out that overlap helps scavenging and hence improves B.M.E.P. We have always appreciated that the biggest obstacle to using a lot of overlap has been it's effect on idling. In this paper you will see that it is suggested that every individual branch of the induction pipe should have it's own throttle. We might at least try it as an experiment. Also make a long duration camshaft up with the maximum amount of overlap and see what we get on the high power engine. We have never run a shaft on a high power engine with as much overlap as on the present Bentley. We certainly do not need to keep an inlet valve open late to get good volumetric efficiency, therefore our existing long duration shaft should be suitable for the job. We should definitely make an Experiment of the separate throttle valves. Rm.{William Robotham - Chief Engineer} | ||