Two-fuel Carburetters and Fittings. XII.
Page 4
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The Efficiency of the Halliday Carburetter is Due Principally to the Injection of Stearn, or Moist Air, as Part of the Charge.
The Halliday carburetter was at one time better known as the Winchester. This device, known under that name to many users, several of whom have , had one or more of these carburetters in use since the beginning of 191], was •invented and patented by Mr. T. E. Halliday, who has been experimenting with paraffin carburetters for 12 years. Prior to the war, the inducementto use paraffin I'as comParativelY small. Although paraffin was cheaper than petrol, for the cornmercaal user who could buy'his fuel in bulk, the difference was not 'law enough to justify any very energetic measures to enable the heavier fuel to be utilized. It is all the more to the credit of the Winchester carburetter, therefore, that it had made considerable headway up to August, 1914, such . large and important concerns as Maple and Co:, Ltd., of Tottenham Court Road, and the London and North Western Railway CO., having fitted it and placed repeat orders. When war .broke out, practically all the chassis fitted with this carburetter were commandeered, and as the Army was hardly likely to spend much time trying to economize in fuel, it is only natural that the paraffinusing portion of the carburetter fell into disuse.
Among the troubles encountered in burning-paraffin in engines de signed for petrol arc : excessive use of lubricatinc, oil, owing in part to the higher temperature necessary when paraffin is being used ; failure of lubricant because the paraffin has not been properly vaporized, or beeitie it has again eondensed in the cylinders and liquid paraffin has run down past the pistons into the crankcase, eventuallythinning the lubricant to such an extent that it fails to act; excessive carbon deposit, and a tendency to knock on very little provocation.
The outstanding, feature of the Halliday carburetter, whereby it is claimed that these troubles are effectively eliminated, is the utilization of a jet,offsteam to accompany the ingeing charge of air and vaporized paraffin. Ibsis Very ingeniously designed, as a reference to our drawingtwill help to confirm. Briefly, the device consists, of two float chambers, one containing ,petrol, for starting pin-poses, and the other paraffin, both connectedto the same jet, with a cock adapted to divert either fuel toorifice
as may be required.. his jet is
situated within a narrow venturishaped choke tube, of such a size that at slow -speeds a fairly rich mixture is provided; at high speeds, the spring-controlled extra air valve dilutes the 'charge. .
So far, as will be seen, the device differs but little from several other
two-fuel4.ttix. Is which we have hitherto described. The novelty consists of an additional jet to ivhich water is supplied'. This jet is situated in another choke tube controlled by a small throttle valve. The connections to the carburetter are so arranged that when petrol is being used the small extra throttle valve, is shut, but on the paraffin's being supplied, then this throttle valve is open according to the strength of mixture required. From the water jet, an additional pipe. runs to the main engine induction pipe, so that a percentage of moist air is carried into the cylinders with each charge. To this feature must be 'credited the efficiency of this • carburetter. The effect of the inclusion of moist air in the charge is to cool it somewhat and thus allow a greater volumetric efficiency on the induction stroke. On explosion, the moisture in the air is-converted into steam, the extra pressure thus obtained providing additional power, and cushioning the explosive effect.
A new company has just been formed to proceed with the mannfactUre of this carburetter , on a large scale. The name of the company is the Halliday Carburetter Co., Ltd., and inquiries should, for the time being, be addressed to Broad sanctuary Chambers, Westminster, London, S.W.