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).
Design, valving, and port arrangement of sleeve valve car engines.
| Identifier | ExFiles\Box 133\2\ scan0155 | |
| Date | 20th June 1935 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X1929 Hs{Lord Ernest Hives - Chair}/Smth.6/KW.20.6.35. Sleeve Valves for Car Engines. We have looked into certain matters connected with the design of an 8-cylinder 3 1/2" bore and a 6-cylinder 3 1/2" bore sleeve valve engine. These are respectively of the same size as the large bore Wraith and Bentley engines. Valving. The most practical arrangement of ports for motor car work is to have 3 inlet ports per cylinder on one side of the engine and 2 exhaust on the other. This system uses one double acting port. The Exe engine arrangement has two double acting ports, and hence better valving, but could not be easily adapted for cars because there is an inlet port on both sides of the engine. With a sleeve valve there is a definite maximum valve area that can be provided for a given piston diameter. This area is less the smaller the duration of the opening. Fig. 1 shows the maximum areas obtainable with a 3 1/2" bore sleeve valve engine compared with the areas on the large bore Bentley unit. The inlet areas are very similar but the exhaust area is about 20% less in the case of the sleeve valve. The sleeve valve may gain slightly by having a better flow into the ports. Comparing the maximum possible valving using a sleeve with that of various other engines, we have :- | ||