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 for a scheme to automatically weaken the engine mixture when the car is over-running.
| Identifier | ExFiles\Box 1\3\ B001_X 93-page05 | |
| Date | 18th March 1912 guessed | |
| (2) The scheme by which I propose, however, to automatically weaken the mixture when the engine is over-running the car is as follows :- It will be remembered that the trouble only occurs when a strong vacuum is in the induction pipe. Fit the induction pipe with a small mushroom valve "A" of about .5 of area (3/4" diam); hold this to its face with a spring of about 7 lbs, which is just sufficient to prevent the 13 lbs. maximum vacuum (which occurs in the pipe when the throttle is shut and the engine running a fair speed) lifting it from its seat. Then arrange the throttle valve with sufficient lap so that the governor after closing the throttle can, with suitable levers, press on the stem of the above mushroom valve "A" so that when the foot is removed from the foot accelerator, and the engine is running at all fast, the governor has no difficulty or hesitation in closing the throttle and opening the small mushroom valve: but when the engine is running slowly on the governor this valve will be definitely closed and air tight. This arrangement will only require a small amount of lap on the throttle piston, and will prevent even a small quantity of carburetted air entering the pipe. I imagine this can be temporarily arranged by the experimental department to see if it is any good. P.H.R. HPH 20.M 100 11/17 (2090 ESTA) 4086 | ||