The Vaporizing Of Paraffin for High-Speed Motors
(Electric Ignition Type)

92 VAPORIZING OF PARAFFIN. complied with, uniformly satisfactory combustion—i.e., a clean exhaust—cannot be obtained under widely varying conditions of load and speed, unless the vaporizer is maintained at approximately a constant temperature, as for instance, by a by-pass throttle on the exhaust connected up to the mixture throttle, and this supple- mented by simultaneous ignition control, for the purpose of increasing the temperature of the exhaust when running slowed down and declutchecl. The temperature found most suitable varies with the vaporizing surface and with the amount of air drawn through the vaporizer, and is also influenced by the method of atomizing—e.g., a mixture temperature as low as 400° to 450° can be used with a vaporizing system in which compressed-air is used ; but with an induction feed vaporizer as found more applicable to a motor of this type, the mixture temperature shoulcl not fali below 600°, nor exceed 800°, when using ordinary lamp-oil, ranging from a density of 800 to 820. As a consequence of this high vaporizer temperature, it is an advantage to limit the amount of air drawn over the heated surface to that just necessary for atomizing the jet, thus keeping down the temperature of the mixture éntering the cylinders to the lowest minimum. Bi-f uel Carb urettors.—The simplest solution of the problem is effected by mixing a proportion of the heavy fuel with the light, and using this in an ordinary carbur- ettor, provided either with a jacketed intake or arranged to draw in its air supply from a sleeve surrounding the exhaust pipe. Fairly satisfactory results can be obtained by this means, pro vided the proportion of paraffin to petrol does not exceed one to four, but naturally varies