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).
Proposal to overcome carburettor high depression issues by using a dual choke system with diffuser type jets.
| Identifier | ExFiles\Box 66a\1\ scan0218 | |
| Date | 28th January 1929 guessed | |
| contd :- -7- It has occurred to us that we might overcome these high depression troubles with consequently an increase of the power output, and still retain our good low speed and snap opening up characteristics by re-arrangement of various parts and the employment of diffuser type jets. FIG 5. The low speed choke would be so arranged that all the air that passed through it would have to pass first through the high speed choke, the same as in the static carburetter. The diffuser jet would be used in both high speed and low speed chokes. DIAPHRAGM SHUT. DIFFUSER JET. DIFFUSER JET ALL AIR IS DRAWN THRO' HIGH SPEED CHOKE. MAIN DIFFUSER COMES INTO OPERATION EARLIER THAN ON PHANTOM CARB. The carburetter piston - equivalent to our air valve - would be gravity controlled and a throttle or diaphragm attached to it so that at low depressions the main outlet from the high speed choke would be shut off and all the air would have to pass through the low speed choke drawing with it the correct proportion of fuel from the diffuser jet. When the velocity becomes sufficiently high in the high speed choke, fuel will be lifted from the diffuser and it can be so arranged that under this depression the piston starts to lift (by obtaining the necessary piston weight) and causes the mixing diaphragm to open the main outlet from the choke. At air flows above this the depression in the carburetter body would remain constant until the air contd :- | ||