SOME NEW CARBURETTERS
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A Résumé of Recently Published Patents.
B. T. Hamilton in designing the carburetter which is the subject of No. 166,977, has set out with the idea of producing a compiment which, while meeting the needs of the average car on average roads, when, as is well known, a comparatively small percentage of the engine power only is needed, will nevertheless, in case of need, as when hillclimbing, proyide_a mixture Sufficiently rich to enable the full power of the engine to be utilized. He points out that the Most economical mixture is one in which the ratio of air to petrol is round about 16 to 1. Most of the time an automobile engine could use a mixture of this strength, but on occasions when sudden acceleration is required or for steep hill-climbittg, a richer mixture, more nearly approximating to 1 to 12 of petrol and air, is desirable. Additionally, when this full power is required, it is of advantage for there to be unrestricted passage for the dense mixture on its way to the engine, .so that the cylinder is filled on each induction stroke.
The inventor achieves his end by the provision of two jets, the principles of operation of which differ. One, the submerged jet, provides a pre-determined quantity of petrol per unit of time, and is influenced by the effect Of engine suction. The other, however, is acted upon directly by the depression 'in the induction pipe so that the amount of fuel will i vary n proportion to the section effect. Both of these jets are variable in size, and are automatically opened with the throttle valve. . Finally, there is a third jet, also affected by engine suction, but -which only commences to open when the throttle valve is almost wide open.
The throttle valve is of the plug type, and when open presents a full-bore passage. On the underside of the valve plug is a comparatively shallow cylindrical chamber of the samediameter as the valve itself. This is divided by a Web which extends across the full diameter of the valve plug and turns with it. The web is so disposed with respect to the valve that it can at no time close an auxiliary air port which is drilled in the under side of this cylindrical chamber. There is a by-pass drilled through the transverse web which allows ecantriunication between one side of the cylindrical
chamber and the other. Finally, a hole communicates between this chamber and the bore of the valve plug.
The main jet. is located below the valve so that its upper end is .disposed just below the passage through the transverse web. The jet, however, is capped by a. plug which rotates with the valve. In the top of the jet there are two holes
drilled. They are located eccentrically and exposed diametrically opposite, one to the other. Two similar holes are drilled in the cap which covers the jet. As the valve rotates, taking the cap with it, it brings these holes more or less into register one with another, and it is in this way that the size of the main jet is varied in proportion to the opening of the throttle valve. One of the holes, the larger of the two, is the jet proper, the other is the auxiliary jet which only opens when the throttle valve is nearly wide open.
The submerged jet is arranged in a tabular boss at the side of the carburetter and the method of controlling its Size is precisely similar to that already. described in connection with the main jet. The control is effected by turning the jet itself upon a cap, both jet and cap being drilled with eccentric holes, and direct communication is established between the throttle valve -lever and one which is coupled to this jet.
The inventor claims (1) that there are no suction-operated moving parts to get out of-order; (2) that the carburetter is of the expanding-type embodying (a) a large free passage for mixture at full
throttle, ensuring dense charges in engine cylinders, (b) a restricted pas in the region of the fuel orifices at degrees of throttle ensuring effic spraying of fuel under all condith
(3) the most economical mixture tin all conditions when power is not wan.
(4) a powerful mixture when it is ware (5) ease of starting from cold; (6) ri and powerful neceleratiop, slow rum either under light load, or when deve ing power.
Other Patents of Interesi
B. t. Aylwin, in No. 166,944, cord his carburetter entirely 'by sleeves rounding the jet. Reference shout( made to the accompanying illustrati of which one shows the position of sleeves with the throttle full open starting or running under a comp tively rich mixture. It will be w that the jet is completely open to influence of air currents. In the sec figure the jet is shrouded by liftin sleeve which protects it from the el of passing air currents. This effect : be varied according to the extent of of the sleeve. If it be lifted sufficie the flow of petrol will entirely cease that without in any way closing the sage from the atmosphere to the en; cylinders, the fuel supply, and there the source of power, will be cut off. important advantage of this is t when running downhill under light in there will be no formation of vacuun the engine cylinders, and therefore transference of engine oil from the ern case to the cylinders. No 166,950 records another additioi the methods of providing for easy tr. .ference of loads from trailers to ID lorries. The 'object of this panic patent is that of eliminating the neces for precise alignment in any direction motor lorry and trailer. The patents E. E. Gobey.
No. 166,986, by E. A. Ashby, is .cerned with engine lubrication, a-11C particularly applicable to two-its engines in the operation of which ere case compression of the mixture is ployecl. The crankcase proper is divi from the oil sump by a partition, communication between the two is eslished by a rotary valve, which °I only when the pressure within the en€ case is at a minimum. The valvi actually tubular and, considering applied to one cylinder only, presents port alternately to the crankcase ant the sump, thus collecting arid dischn
ing the oil residue. There is, co: quently, at. no time, direct communica between the two divisions of the erz. case.
The omnibus seat cover, which fo the subject of No. 166,979, by J. Lt is supported on a light frame-wet-1c .wl automatically locks in the vertical p tion when not required for use.
An attachment to enable an ordin tractor to be used for steteh plough is the subject of No. 167,042, by S. Darby.
The spare wheel carrier which patented in No. 166,910, by L. Es schild.4 has three arms, of which ore toggle:jointed, and by its manipulai provides for instant release ofthe si wheel which is being supported.