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).
Page from a gasoline manufacturer's journal detailing the 'C.F.R.' Carburetor and its ignition system.
| Identifier | ExFiles\Box 27a\4\ Scan072 | |
| Date | 1st November 1931 | |
| 116 REFINER AND NATURAL GASOLINE MANUFACTURER NOVEMBER, 1931 Figure 5, and by the drawings, Figure 6 and 7. It is shown attached to the engine in Figure 1. The location of essential operating controls is indicated in Figure 5, and shown also for the 4-bowl type in Figure 7. The sectional view, Figure 6, shows the fuel jet and the air-bleed tube which enshrouds its tip. rator which forms a part of the outfit, is used in conjunction with a suitable interrupter mechanism. When using magneto ignition, a magneto is driven directly from the crankshaft through a flexible coupling. This direct form of connection for the magneto eliminates the back-lash that would be present if the driving were done from the camshaft, and it gives an armature speed which is the same as the engine speed. The latter is desirable on account of the slow engine speed at which knock testing is done (600 r.{Sir Henry Royce} p. m.{Mr Moon / Mr Moore}). One spark in each cycle is thus wasted, but it comes at the end of the exhaust stroke. The spark plug used is the 18 mm. size. The proper spark gap setting is 0.025 in. Interrupter points should have gaps set at 0.015 in. for battery-type ignition and at 0.020 for magneto ignition. The timing of the spark is indicated on a graduated scale (shown in the photograph, Figure 1) by the flashing of a neon-tube spark indicator. This indicator consists of a small neon tube carried behind a slot in a disk which is fastened to the crankshaft and which rotates inside a non-conductive ring, to which a circularly graduated metal scale is attached in proper position relative to the neon tube. From the metal scale a lead is carried to the high-tension side of the FIGURE 5 Photograph of the "C. F.{Mr Friese} R.{Sir Henry Royce}" Carburetor Two-Bowl Model The exits of both are located at the venturi throat. The fuel jet is fixed in size, the amount of fuel that it feeds being regulated by the volume of air entering through the air-bleed tube. The air jet has an adjustment at its inlet end which is set by turning a thumb screw to which is attached a graduated dial for indicating what the setting is at any time (see Figure 5.) The form of the down-draft inlet tube and the directness with which it connects to the inlet port of the engine are shown in Figure 6. The throttle which is of the barrel type, not a butterfly, is there shown in closed position. There is one fuel valve with companion air-bleed valve for each float bowl. The fuel valve, which is a stainless steel needle held on its seat by a suitable spring, is placed as close as possible to the fuel jet in order to keep the length of the fuel channel at a minimum. The air valve is a lapped stainless steel cylinder which operates as a gate valve to open and close the proper air-bleed passageway. The two valves in each set are operated as a unit with a single control, in such a way that the opening or the closing of one of the air valves opens or closes also the companion fuel valve. THE IGNITION SYSTEM Either the battery-type or the magneto system of ignition may be used. For battery-type ignition, a standard 6-volt coil taking primary current not from a battery, but from the small direct-current gene- FIGURE 6 Sectional View of the "C. F.{Mr Friese} R.{Sir Henry Royce}" Carburetor Two-Bowl Model Image Labels: Figure 5 Diagram: INTAKE MUFFLER FUEL CONTAINER SIGHT GAUGE SHUT-OFF PLUNGER FOR FUEL AND METERING AIR DRAIN COCK METERING AIR ADJUSTMENT WITH GRADUATED DIAL FLOAT LEVEL SIGHT GAUGE THROTTLE CONTROL KNOB | ||