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).
Carburetter development, detailing the relationship between depression and air valve lift, port design, and results from a 10,000-mile road test.
| Identifier | ExFiles\Box 5\4\ 04-page164 | |
| Date | 17th March 1926 guessed | |
| contd :- -4- We then take a curve connecting depression and air valve lift on a normal carburetter in which the air valve is governed by the spring to be employed. It is clear that for a given spring the air valve lift will depend only upon the depression. From these two curves obtained it is possible to proportion the diluting ports to give the area required for smooth running at any position of the air valve. Appended is a sketch of the apparatus used. Results obtained by this method indicate that the air ports required in the dash pot vary but very little from the present standard fm form but the contour of the diaphragm ports i.e., the ports at the upper end of the high speed choke, assume a contour similar to the main air ports. A carburetter has been constructed on these lines in order to obtain more information from its behaviour under running conditions on the road. It has been fitted to 10-G-111 which is about to start a 10,000 miles test in France. Since making the carburetter we have improved slightly some of the details of the 'adjustable' test carburetter described above and are engaged upon proportioning as accurately as possible the air ports to suit the standard chokes, aluminium air valve and valve spring. With regard to acceleration, tests have been made on the road with the diffuser jet Sch. 592 which it was thought would improve this feature, but up to the present it has not shewn much promise due to, we imagine, the capacity of the contd:- | ||