An Interesting Oil-Fuel Carburetter
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WITH a view to reducing fuel cost, many operators are interested in devices that aim at burning oil in engines of normal design. Such a function is performed by the Delco oil-fuel carburetter, which is of German origin and Is handled in this country by the Heico Engineering Co., 16, Canning Place, Liverpool. It is intended for use in conjunction with the normal petrol carburetter, which is used for starting and warming up.
The Heico device consists of a normal float chamber with a metering orifice or jet and a spraying jet in series. The last-named is arranged horizontally and protrudes into a down-draught choke. Incorporated in the cast body of the instrument is an exhaust-heated jacket and, by means of a cowl, the inlet air is warmed by passing over the surface of this jacket before it enters the down-draught choke shown in the drawing on the right.
After passing through the choke, the mixture of air and sprayed fuel reaches a chamber which is surrounded by the exhaust jacket. At the outlet end is a vaporizing cone perforated by a large number of small holes through which the mixture passes, its state of vaporization and atomization being brought more nearly to completion as it does so.
To install the Heico carburetter, a hole is cut in the exhaust manifold and a flange is welded on to it. To this the lleico device is bolted and a pipe is installed to connect the outlet of the heating jacket to some other point in the exhaust system. Between the petrol carburetter and the inlet manifold a change-over valve is placed and to this a pipe leads from the outlet of the Heico carburetter. The change-over valve is connected to a separate lever on the dashboard and the additional throttle, which eerves when the petrol carburetter is out of action, is coupled either directly to the accelerator pedal or to the throttle of the petrol carburetter. When the engine has been warmed up on petrol, the driver changes over to the Heico inktrument. For slow-running and " small-throttle " work, it is desirable to change back to petrol, as, otherwise, crankcase dilution may become severe. Given intelligent use, however, this trouble is said not to be noticeable, provided that a vaporizing oil is used.