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

VAP0R1ZATI0N IN THE HIGH-SPEED MARINE ENGINE. 89 if an induction feed is used, the mixture must either pass through the crank-chamber, which is bad for the bearings, or be compressed in a cylinder extension ; or again, if a fuel injection pump is used, this is necessarily small and ill-adapted for accurate adjustment and the high speeds at which motors of this type are run. Re- ferring to the illustration, this shows a very practical way of avoiding many of the difficulties experienced in the successful use of paraffin, in a high-speed two-stroke motor of the simple enclosed crank-chamber type. It will be seen that the float cistern is fitted with a pressure- tight cover and connected by a duet r, so that the surface of the fuel shall be subjected to the varying pressure in the crank chamber. In action, the piston, when nearing the completion of the downstroke, releases the terminal pressure to the exhaust outlet x, and simultaneously aclmits a charge of air under a pressure of 4 to 5 Ibs. from the crank-chamber along the communicating port- way a ; and at the same time causes a jet of fuel to be projected 011 to the baffle b of the piston by induction effeet; when, partly as a result of the heated surface of the baffle plate, partly to the high velocity of the ingoing charge, and in some degree to the heat imparted to the air, the fuel is by this means sufficiently vaporized for a motor to run in a manner more satisfactory than might be expected. Judging from one inspected by the writer, starting on petrol presents no difficulty, and the change-over to paraffin can be made within three to four minutes—the time required to use up the supply of petrol in the cistern. To start, the two-way plug t is first moved over to position 1 for emptying the paraffin out of the cistern ; it is then moved a quarter turn to