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).
Technical description of different carburetter arrangements and their operational principles.
| Identifier | ExFiles\Box 5\4\ 04-page225 | |
| Date | 13th December 1929 guessed | |
| (2) It is also preferable to multiple jets because of the difficulty of the imperfect way they come successively into action. Probably the best arrangement of this carburetter is in the vertical type, (but it can be arranged vertically or horizontally) It will be noted that the fuel jet is subjected to the direct suction of the engine, whereas the air can without loss of crisp metering efficiency be made to turn many corners at slow air speeds before it joins the fuel. In the inverted pattern it is claimed that it is novel to take the emulsion air directly in the top of the emulsion standpipe as shewn, and a safety overflow pipe in the centre to prevent flooding into the engine. It is claimed in this scheme that we can regulate or adjust the mixture strength by controlling this emulsion air as shewn in the drawing, and/or by moving the restriction bush relative to the needle also shewn. It will be seen that a core of emulsioned fuel of increasing strength, even with constant suction, enters the centre of the main air stream which in turn is surrounded by a stream of extra air increasing in air speed and quantity with the speed of the engine. Naturally the increasing capacity of the carburetter has for its object the prevention of an excessive depression in the induction pipe system which would result in a decrease in the weight of charge taken by the engine, and consequently its HP. (usually termed lower volumetric efficiency.) Conversely at reduced load it is very desirable to maintain a fairly vigorous suction on the carburetter, otherwise the mixture strength varies because the fuel is not metered correctly, or emulsified, or atomized) sufficiently to travel along the induction pipe and divide with correct proportions of fuel and air to the various cylinders - good metering and good distribution better maintained under all conditions.) Another novel feature of this carburetter is that the air depression (suction) is taken from that part of the venturi where this depression is greatest - i.e. probably nearly 3 times that of the restored pressure just near the wide open throttle, and used in a special suction cylinder having a special piston arranged to be air damped. This has for its object the earlier and more certain action of | ||