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Two-fuel Carburetters and Fittings.—IX.

13th July 1916, Page 4
13th July 1916
Page 4
Page 4, 13th July 1916 — Two-fuel Carburetters and Fittings.—IX.
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The Maclaren Petrol-paraffin Carburetter, Hitherto Applied to Motor-boat Engines, but Suitable for Use on Commercial Vehicles.

In the Maclaren two-fuel carburetter, a. description of which forms the ninth article of our series, we have another example of a. fitting which is proving satisfactory on internal-combustion engines, in this case for motor-boat work, although not hitherto applied commercially to road vehicles. This interesting device possesses one or two features of novelty, which are the subject of patents. A bid for simplicity has been made by the maker, Maclaren Bros., Ltd., of Dumbarton, by eliminating from the mechanism two-way cocks or similar apparatus for alternating the fuels.

Description.

For (he complete device, besides the two fuel tanks, two separate but simple carburetters are fitted, one for petrol, the "other for paraffin, with an engine throttle valve and the usual exhaust-gasheated vaporizer. The throttle valve itself is of special design, and by its use the need for a two-way cock on the supply pipe is obviated. In the illustration, which we reproduce on this page, the. throttle valve is shown in the mid position with the hand-control lever similarly placed.. For lies e of clearness, the connections between the hand lever and -throttle-valve lever are shown as if direct, and no account is taken of intervening rods

or levers. It will be noticed that there are three openings into the throttle-valve chamber, one from the petrol carburetter, and another from the vaporizer (which serves as a passage for the paraffin mixture), whilst a third opening is from a spring-controlled extra-air • valve. It may be observed that, with the valve in the position shown, all three ports are closed. The opening from the valve tothe inlet valves of the engine is at the end of the. throttle-valve barrel, so that the gases enter at the side and travel to the cylinder along the axis of the valve. Movement of the throttle-valve lever in one direction opens only the gas passage from the petrol carburetter and that from the extra, airvalve ; in the other direction, ittopens the passage ; a start can then be made as from the extra air valve.In starting the engine, therefore, all that is necessary is to throw,the control lever over in. the direction which will open the petrol mixture passage ; a start can then be made aa ordinarily with an engine entirely petrol-fell After a few minutes running, when the motor is thoroughly .warmed up, all that is necessary is to throw the hand lever o.ver in. the other direction. and place the cylinder into communication, through the vaporizer, . with the :paraffin carburetter and also with the extra air valve. Both carburetters are designed to give a rich mixture. The areas of the extra air and mixture ports are suitably proportioned, and sufficient air admitted to dilute this rich mixture, so that a combustible

i gas s led to the engine.

The Vaporizer.

The vaporizer used with this system is simply a box cast round the exhaust pipe with baffles arranged inside it, so as to deflect the rich paraffin mixture and cause it to pass round the hot exhaust pipe and at the same time to. be in close contact with it, and thus extract as much heat from it as is desirable. It will be gathered that almost any carburetter can be used to supply the petrol. The paraffin carburette'r also is quite simple, and it would appear that it could be manufactured very cheaply.

Patented Feature.

The patent taken out by Maclaren Bros., Ltd., may be stated briefly as covering means for the supply or both light and heavy fuels to internal-combustion engines, consisting of separate supply and mixture chambers for the fuels, and of a control valve adapted to admit one or other of-them as well as a supply of auxiliary air. This statement does not describe all the claims-made out, but indicates the principal one, •

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