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

12 VAPORIZING OF PARAFFIN. ■combustible to be injected at each pulsation is limited to 1 volume for a minimum of 8000 volumes and a maximum of 12,000 volumes of air; or, in other words, 1 Ib. of petrol must be mixed with 15 to 20 Ibs. of air to work with anything approaching to a reasonable efficiency; in tilis connection it is useful to remember that a mixture of 1 to 10,000 produces the most forcible explosive effect. Hence, in an engine having a 6-in. by 10-in. cylinder, the capacity of the injection pump must be approximately 0'028 cub. in. per stroke; i.e., a piunger of 0'5 in. diameter will require to be operated with a stroke limited to 0-156 in., from which it will be seen that the piunger displacement for a liigli-speed motor of the size commonly used in automobiles would be extremely difficult to regulate with the necessary degree of accuracy ; but, as pointed out, even if this difficulty can be got over, it would be necessary to provide a separate pump for each cylinder. Snifting Carburettors.—Spray carburettors of this type, when used in conjuiiction with either a mechani- cally or a pressure-flow operated inlet mixture valve, and provided the motor is not requii-ed to be run over a wide range of speeds—as, for instance, in the propulsion of motor boats and for many industrial purposes—are capable of producing fairly satisfactory results, and are much favoured by users and makers alike, owing to their simple action and low cost of manufacture. Of this type there is considerable variety, but most re- semble in essential construction one or the other of the examples illustrated by Figs. 3 to 5; of these it will be noticed the first is shown arranged with a mechanically operated snif ting valve v and the cam-lever mechanism k