Two-fuel Carburetters and Fittings I.
Page 4
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The Merits of the King Paraffin Attachment to Zenith Carburetter Discussed,
The condition of the fuel market is such that any alternative to petrol which shows signs of being of real practical use is sure to be welcomed by the commercialvehicle user. As a result, there has been, of late, considerably increased activity on the part of those individuals and concerns interested in the manufacture and sale of attachments to existing
carburetters, by the aid of which paraffin as an alternative fuel may be used. • The King Paraffin Attachment.
One of these which is rather to the fore at present is the King attachment. We were recently afforded an opportunity of inspecting this device, and we may say that we were favourably impressed by its simplicity and also by its effectiveness. This device, which is called the King Paraffin Attachment, is, as its trade description implies, an "extra," in. that it is an addition which can be made to a standard carburetter, enabling paraffin to be used lotthe maj-or part of the vehicle's running. It is at present only applicable to carburetters having two or more jets. The one which we saw, and which was fitted to a Burford twoton lorry, had been arranged to suit the Zenith carburetter, for which it may, he stated to be particula,rly well adapted. In this regard, it is interesting to note, in passing, that Mr. King has been successful in securing from the Zenith Co., what we believe is the first licence, in this country, to Operate under Zenith patent number 2599, of 1913.
B20 Description.
The outfit consists of a heating apparatus for raising the temperature of the paraffin fuel, a float chamber for paraffin only, and an exhaust-gas-heated muff which surrounds the short piece of induction pipe between the carburetter and cylinder. The paraffin float chamber is coupled only to the main jet of the Zenith earburetter, petrol only being allowed access to the compensating jet. From the construction of the Zenith carburett,er, it follows, that, when starting up, petrol only is admitted to the engine, and on a cold day it is advisable to let it run for some four or five minutes with the throttle . nearly closed, in which position the compensating jet alone operates, so that the engine is thoroughly warmed up before admitting paraffin.
Perhaps the most ingenious part of the King attachment is the device for warming the paraffin before it enters the float chamber. It consists of a short portion of exhaust pipe. fitted with a bypass, round which is cast an annular chamber with inlet and outlet unions, which are coupled to the paraffin supply tank and float chamber respectively. In the exhaust pipe proper, and situated just past the engine end of the by-, pass, is a butterfly valve which is operated by thermostat.
Mr. King has found, as a result of experiments, that paraffin fuel is at its beet when kept at a certain uniform temperature. With the use of the by-pass, combined with the thermostat and butterfly valve as shown, it is possible automatic-' ally to regulate the amount of heat which is passed to the paraffin in the annular chamber. When. the temperature tends to exceedthat desirable point, the thermostat and butterfly valve allow a greater percentage of the exhaust gas to go 8traight through without using the by-pass. With the temperature below the critical point, the throttle valve closes.
A Test Run.
We enjoyed a short test run on the Burford; fitted as described, and we were very pleased indeed with its behaviour ; to all intents and purposes there was no difference as between this and one using petrol. Over a fairly long rim, with a loaded two-ton chassis, the following results were, attained —an average speed of 13.5 miles per hour ;• proportions of paraffin and petrol used throughout, 72.7 per cent. and 27.3 per cent. respectively; .the actual consumption of paraffin worked out at 12 miles per gallon exactly," the paraffin. being the ordinary commercial article as purchased at any oil-shop. From our own experience we were able to observe that the engine started up at once as it would in normal circumstances without this attachment. There was no visible emission of vapour, and almost an entire absence of smell, during our short run : we had a friend following us, on a motor-bicycle, and he also can testify to this. Furthermore, we made some experiments inthe way of rough usage of the throttle lever, such as rapidly accelerating the engine after a few moments slow running without being able to produce any emission of visible smoke or vapour. The existing tank is used for paraffin, and a. small one is fitted for petrol.
The King attachment is sold by Lawrence King and Co., 122, Alma Street, Birmingham, Mr. Lawrence King, the managing director, being the patentee. The price is 215.