An Improved Automatic Vaporizer
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Simplicity of Control a Feature of the Latest Headen Hamilton Apparatus
ONE of the first devices for running ‘..../petrol engines on vaporizing oil to be marketed and extensively used in this country was the Headen patent oil manifold made by the Headen-Hamilton Engineering Co., Ltd., 10, Finsbury Circus, London, E.C.2. In its latest form this apparatus consists chiefly of a combined inlet and exhaust manifold of special design, an anti-detonating device, and a Zenith double-floatchamber carburetter with the latest starting device.
This standard carburetter is only slightly modified to suit the special requirements, and it automatically enables the engine to be started and to idle on petrol, whenever the accelerator is in the position of rest An auxiliary petrol tank is supplied for this purpose.
Directly the accelerator is depressed, the petrol supply is cut off automatically. Simultaneously the throttle is opening and suction begins to draw and atomize oil fuel through the main jets. The first lever and that of the throttle valve are mechanically interconnected. It is thus impossible either to mix the two fuels or to run on other than oil.
The atomized fuel-air mixture passes into the induction manifold, which is almost completely surrounded by the exhaust Here the fuel is claimed to be thoroughly broken up, the heavier wet particles being precipitated on baffles, and the entire charge finally vaporized into a dry gas. Thus the oil vapour enters the cylinder in a suitable state for the promotion of complete combustion, with the minimum of condensation on the cylinder walls and no undue carbonization. Moreover, it should be noted that what carbon is formed is soft and easily removed.
The exhaust discharged from engines fitted with this vaporizer is clear and reasonably odourless on the road, but a puff of smoke may be visible when slowing down sharply, or before the engine has reached its proper working temperature. Usually it is possible to get away from a cold start within from three to five minutes, but normal engine heat and best output naturally are not attained under 20 to 30 minutes. Thermostatic control would, of course, be advantageous.
Detonation is liable to occur when running on oil and employing a high compression ratio, because the self
igniting temperature of oil under cold conditions ia below that of petrol. To obviate this a small quantity of exhaust gas is introduced at the carburetter intake, thereby modifying the proportions of fuel and oxygen to accommodate the higher spontaneouscombustion temperature of oil fuel.
No claims are made for increased mileage per gallon or better pulling. Generally, however, engines are found to be more flexible on oil, and consumption figures are usually improved. On the other hand, the power output is not quite equal to that on petrol.
The Headen-Hamilton Engineering Co., Ltd., specializes in the production of vaporizing equipment for Fords and Fordsons.