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 sleeve valve and poppet valve engine performance characteristics.
| Identifier | ExFiles\Box 133\2\ scan0136 | |
| Date | 1st February 1935 | |
| -2- (3) Volumetric Efficiency. We said that from our superficial investigations we had come to the conclusion that it would be difficult to get the same volumetric efficiency from an in-line engine with sleeve valves as from poppet valves. Fedden produced figures to show that on a naturally aspirated 5" bore engine he got 10% more M.E.P. with sleeve valves than he did with two poppet valves. He showed 130 B.M.E.P. at 3,400 revs. on this engine running with 7 1/2 to 1 compression ratio. On this particular sleeve valve they are using about 180° of the cylinder circumference for ports. (4) We pointed out that we expected trouble with the carboning of the ports when running at a reduced throttle. Fedden had no experience on this but had just completed 200 hours running at cruising load at 115 B.M.E.P. on one of his single cylinders. He had not experienced any carboning, but he had not run idling for long periods. (5) Noise from the Sleeve Drive. Fedden said that noise from the sleeve drive - which we understood from him is substantially the same as the Ricardo drive used by us - was unlikely to be a source of trouble, as the wear on the parts was negligible. (6) Junk Ring. Fedden admitted that at high outputs this was probably his most difficult problem. In view of these remarks, and of the success which the Bristol Company are undoubtedly having at present with their sleeve valve engines, we suggest that it is worth investigating the single sleeve in relation to an in-line car engine, and if the results seem reasonable, to put a single cylinder in hand. We are concerned at the multitude of pieces which are required to obtain silent valve operation by means of hydraulic tappet adjusters, and from American practice these seem to be necessary whether side valves or overhead valves are used. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||