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

VAPORIZATION IN THE HIGH-SPEED MARINE ENGINE. 87 The attainment to a practically perfect method for vaporizing flash-proof oils in high-speecl motors of the electric ignition type has engaged a very considerable attention for a number of years, as will be gathered from the widely varying methods already described, but in too many cases the problem has been under-rated, especially where the running conditions imposed, as in road cars, electric lighting, and to a less extent in motor- boats, are extremely variable. Other vaporizing methods that have been tried in connection with four-stroke high-speed engines than those described may be men- tionecl : (1) The Bryant-Watling system of alternate expansion and contraction of the mixture in an exhaust- heated vaporizer ; (2) the Cremorne, in which the heated mixture is caused to circulate with a cycloidal move- ment ; (3) the Davis, having a whirling action com- municated to the mixture in contact w^th an exhaust- heated surface ; (4) the Loew system of indicating the temperature of the vaporizer, and the time required for warming up before changing over to paraffin ; (5) the automatic method de vised by Dorwald for attaining the necessary temperature before changing over from petrol to paraffin, by means of a thermo-electric coil. Two-Stroke Petrol-Paraffin Motors.—Obviously for small two-stroke motors of the enclosed crank-chamber marine type to be run on paraffin, the fuel must either be (1) fed in admixture with air direct to the crank chamber and thence through an exhaust-heated vaporizer during transfer to the cylinder ; or (2) be injected by a pump on to a vaporizing plate or bulb in the combustion chamber, or on to a baffle on the end of the piston ; or, (3) be forced into the cylinder under air pressure from a