A Heavy-fuel Gasifier Tested on the Road
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IN our issue dated November 17th we gave a description of the Rector Gasifier, which is designed to permit the use of heavy fuels in ordinary petrol engines. This device is marketed in Great Britain by the Buda Co., England, Harvey Works, Wembley, Middlesex.
A sectional drawing is reproduced to explain the design. There are two float chambers, both fed from the main supply of Diesel oil or gas oil. One feeds an annular fire trough and the other a jet located in a venturi tube which passes vertically through the centre of the trough. Through this tube air is drawn by engine suction, the draught causing rapid combustion of the oil in the trough, so that the heat Di the air passing down the central tube is approximately 2,000 degrees P.
The engine is started by a primer which injects petrol into the induction pipe, as well as into the fire trough above the level of the heavy oil. A sparking plug, wired in series with one of the plugs of the engine, is located above the fire, trough and, when the engine is started, this ignites the petteri vapour above the:.oil.
With the firing of the engine upon the primed charge of petrol, air is drawn through the venturi, causing the petrol in the fire trough to burn at such a rate as to generate sufficient heat to ignite the heavier fuel ; thereafter it burns freely so long as the draught is maintained.
The engine speed is controlled by a butterfly throttle of orthodox type, in which are twu holes to provide for slow running ; when the throttle is wide open these holes are automatically cleaned by what are termed knock-out pins. There is a weighted extra-air valve, also a choke, to give a rich mixture when the engine is not yet warm.
About six weeks ago the Buda Co., England, fitted a Rector Gasifier on an old Buick car of 24 h.p., R.A.C. rating. In the interim the car has coeered about 1,100 miles in ordinary service, including several long journeys, and there bee been no serious trouble or involuntary stop that could be attributed to the design of the gasifier. The engine has been taken down and, according to the company, was found not to he sufficiently fouled to require decarbonizing. Cu
fortunately, we did not have the opportunity for examining the cylinder head, valves, crankcase oil, etc., when the engine was dismantled, but shortly after its re-assembly we undertook a short test of the device in service.
On the morning of the test the engine was not started prior to our arrival at the works, and the cooling-water temperature was found to be 44 degrees F. After three squirts with the primer, the engine started at once, using the electric starter. It faltered and stopped twice, and for the first 14 minute needed occasional priming with petrol, amounting, in all, to six depressions of the plunger. Thereafter the firing was regular and, with the choke closed for the first five minutes, we drove straight away.
There was at first a considerable emission of bluish-white smoke from the exhaust pipe, this diminishing, and finally disappearing altogether seven minutes after starting.
If the engine was run slowly, as when traffic held up the vehicle, getting away was accompanied by a small puff of smoke, as is common with compression-ignition engines, but, ordinarily, the exhaust was quite invisible.
The car appeared to have rather, less power than one is accustomed to expect from a Buick car of this model, but the fact that it was six years old and that the engine was unquestionably in a bad condition must be allowed for.
The point which interested us, however, was the smoothness of running and the good engine torque developed at slow speeds. The clearness of the exhaust indicates that fairly complete combustion was obtained, and a good feature is that the main-jet supply can be adjusted by a needle valve, so that too rich a mixture is easily corrected. When the engine was stopped for seven minutes it was found possible to restart without priming.
In 1 hour 30 minutes the distance travelled was 22.5 miles, and 10e. pints of fuel were consumed, this representing consumption at the rate of 17.4' m.p.g. The fuel used wae Shell-Mex gas oil, sold as having a specific gravity of between .84 and .86 and costing about 5d. per gallon.
The nature of our test precludes us from making any authoritative statement as to whether there is any serious carbonization or pollution of the crankcase lunricant.
At present the price of the im.ported gasifier is £35, but the company definitely intends manufacturing in this country, when it is expected that the price will be reduced. Also it is intended to manufacture a smaller model for light commercial vehicles and, possibly, for private motorcars.