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).
To the Patent Office explaining the requirements for a carburetter to work with a dual induction pipe system.
| Identifier | ExFiles\Box 147\3\ scan0137 | |
| Date | 27th August 1938 | |
| To Mr. Walker. Patent Office. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}8/JH.27.8.38. THE DUAL INDUCTION SYSTEM. Further to our memo. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}3/R.10.8.38. This is intended to explain more fully the actual requirements of the carburetter to work satisfactorily with the suggested dual pipe. or ? It is desireable that the carburetter should be either of the semi expanding or fully expanding type as will be seen from the following- We have virtually two induction pipes to cater for, but a definite speed of change over at which the larger pipe comes in, cannot be stated as a set figure in miles per hour, because under certain road conditions, it is possible to cruise at a relatively small throttle opening, under which condition running on the small section of the pipe would enable maximum economy to be maintained. Road and wind conditions vary however, so that a larger throttle opening can be required to maintain the same road speed. It is clear therefore that the action of opening up the larger bore pipe, to augment the supply of the smaller one, must be a function of engine requirements. This requirement can best be summed up by the fact that the power developed in a given engine at any speed (engine) is in direct relation to the absolute pressure in the induction pipe at that engine speed. This is the variable therefore that we should make use of to determine when the larger pipe should be brought into action, we might say therefore in describing the necessary carburetter to work with the dual pipe 'That in conjunction with an expanding carburetter of suitable design, the bringing into action of the larger pipe is automatically beought about by the expanding action of the carburetter. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} | ||