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).
Variable valve gear design from the R.A.E. for single-cylinder water-cooled engines.
| Identifier | ExFiles\Box 43\3\ Scan210 | |
| Date | 17th November 1928 | |
| To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Lr.{Mr Ellor} Lr{Mr Ellor}1/LG17.11.28. X9003 +3560 As arranged during our recent conversation, we enclose blue print of the variable valve gear obtained from R.A.E., shewing their standard arrangement for changing the period-phase and timing whilst the engine is running. you will observe that the battery of cams having different periods, are placed upon a sleeve. A selector gear is arranged to operate the exhaust and inlet independently. R.A.E. are at present engaged upon the design of an overhead gear for single cyl. water cooled engines. They are mounting the cams permanently on the driving shaft without the sleeve, and providing a spline in the driving gear so that the whole shaft moves along to bring a different cam into operation. This has the advantage of keeping the radius of the cams small and shorten the length of shaft. A battery of three is considered sufficient. The operation is carried out by skew gears. A further provision is made for change in compression ratio by arranging the vertical drive shaft to telescope with a spline drive. I think it very advisable if at all possible to include the variable timing features and an arrangement whereby the compression ratio can be changed without having to change pistons. Lr.{Mr Ellor} | ||