NEW CARBURETTER DESIGNS.
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A Résumé of Recently Published Patents.
This week's patent specifications are of considerable interest, to all who are concerned with carburetters. Several of those patents with which we, have to deal relate to that important component of an internal-combustion engine, No. 146,965, by D. Pordes, has a curious arrangement of jets. The float chamber is immediately below the throttle valve. The hollow spindle of the latter descends into the petrol, which flows into the interior of the actual butterfly throttle valve, from which it escapes through narrow holes drilled in the body of the valve. There are threinsuch holes. Two of them are axially _ opposed one to another, so that they form practically one continuous passage leading from OTIO edge of the valve to the other. This passage is at right angles to the axis of the valve, and it emerges at the extreme tips of the valve so that when the latter is nearly closed, the ends of the passage are quite close to the inner walls of the pipe. The third hole is almost at right angles to this and communicates between the outside of the boss of the valve and the hollov7 fiffierior. Ja,•small internal cylindrical slide is provided capable of being moved up and down inside the hollow spindle of the valve. It affords means of adjusting the size and operation of the jets.
The action is as follows: The engine is started with the valve practically closed. Air is drawn through the long passage running from end to end of the valve, and a rich mixture emerges, passing thence into the induction pipe. When the throttle valve is opened the tendency for air to travel this wayis considerably diminished. Instead, it passes by the main surface of the valve and draws fuel out of the third hole, which opens out at the side of the boss of the valve.
Another invention dealing with fuel supply is No. 149,945, by L. Renault. This inventor proposes to provide, two
carburetters for one engine. One of them is controlled by the accelerator pedal, the other by a governor, or some similar means. . The latter only comes into operation beyond a predetermined speed, say, for example, 1;000 'revolutions per minute, at which sReed the motor is fully loaded. Subsequent to this speed, however, the gove.rnor-controlled carburettor comes into use progressively in such a manner that the depression in the induction manifold is maintained at a value which gives sufficient gas speed to ensure a good mixture. As an example,of the working of this dual carburetter arrangement we may consider what happens when an automobile is pulled up: The speed of the engine, which may have been, say, rotating at a. high number of revolutions per minute, gradually decreases, as also does the depression in the induction pipe. It follows that the speed of the gases in the induction pipe decreases in its turn and becomes !insufficient to ensure that good mixture which is nem: sexy in order to maintain the engine torque at or near its maximum. At least that is what occurs when, as is customary, only one carburetter is used. With the arrangement now suggested, however, by the time the engine had slowed down below 'the predetermined speed, which we have taken in this case to be 1,000 revolutions per minute, the governor-controlled carburetter would have ceased to function, leaving only one carburetter operative. The speed of the gas iii the induction pipe in these circumstances will be fairly well maintained, thus ensuring continuous atomization of the mixture and non-deviation of the torque from its maximum figure.
The carburetter Which is described in No. 169,319, by the Austin Motor Co., Ltd„ is intended mainly for use in conjunction with lighting sets, adesirable feature of which is that they shall be capable of automatically starting, from time to time, in accordance with the demand for current., condition of the
batteries, and so on. It is pointed out by the patentees that such a carburetter must be simple and economical. :The latter condition involves the fitting of a comparatively small jet, which makes starting after a comparatively long
stoppage somewhat difficult.. This invention 'embodies a device to overcome the last-named difficulty. The carburetter is fitted with two jets, of which the larger, which is meant for starting, draws its supplies from a small reservoir, which is slowly filled from the main chamber by means of a wick. After the engine has been stood for some time, this chamber will be full, and will provide petrol for the larger jet for starting purposes. It is soon exhausted, however, and theitafter the supply of fuel is at such "a slow rate that it does not affect the economy.
In the carburetter which is described in specification No. 169,345, by E. Feroldi, the feed to the jet, although controlled by a float in the ordinary way, is nevertheless a direct one.
An improvement in the Madison Kipp lubricator is the subject of No. 166,101, by the Madison-Kipp Corporation. The object of the invention is to prevent the lubricant leaking back along the plunger and rod and escaping on to the hands of the operator. We reproduce one of the drawings from the specification, from which it will be seen that the lubricator consists of a small receptacle for oil, below which is a. handoperated plunger, by the operation of -which a predetermined quantity of lubricant may be impelled to the bearing or whatever it is that requires lubrication. Experience has shown that in a device of this kind oil will invariably leak past the piston to a, certain extent, with the unfortunate result already mentioned. To prevent this occurrence an annular groove is cut in the wall of the pump cylinder, in such a, manner that it is in communication with the passage between reservoir and cylinder.