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A PAGE OF CARBURETTERS.

4th October 1921, Page 48
4th October 1921
Page 48
Page 48, 4th October 1921 — A PAGE OF CARBURETTERS.
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Which of the following most accurately describes the problem?

A Résumé of Recently Published Patents.

We have this week, in our survey of the Patent Office records, come across an outcrop of carburetter inventions. They appear to deal with almost every aspect of this important problem of carburation. Those we have selected are the ones which appear to us to be most important, or most. intevesting.

No. 167,807, by F. Pokorny, is not, strictly speaking, a carburetter: it is an accessory which fits between the carburetter itself and the induction pipe proper. 'The object is automatically to control the, volume of fuel supplied to the engine, proportionately to its requirements, in order that neither more nor less fuel may be admitted to the intake manifold than will satisfy the efficient consumption needs of the engine in

all its speed variations. The inventor points out, that, ordinarily, in controlling a motor vehicle, the chief difficulty occurs because of the fact that it is alinost impossible by hand control so to vary the adjustment of the throttle-valve as ,to regulate the supply of fuel correctly in accordance with requirements at all speeds. With this fitting applied, however, it is anticipated that this difficulty will be overcome. The control is actually effected by the engine suction,. which operates to.lift a valve which, as it lifts, increases the area of the opening for the passage of the explosive mixture. , There is a central fixed obstruction in the middle of the passageway from the carburetter to the induction pipe. It is in the form of a double cone, with the largest diameter in the middle of its length. This double cone has a venturi passage through the middle of it, which affords sufficient area to admit of the passage of sufficient mixture to enable the engine to turn over slowly when idle. A sleeve outside this valve Or obstruction is formed with an interior

taper bore. In its lowest position it practically closes the passage past the periphery of the largest portion Of the double cone. As the engine suction increases, however, this sleeve is lifted, and, owing to the taper of the bore, a

C60 gap is formed round the edge of the conical obstruction past which the mixture may flow.

An important feature of this invention is an arrangement whereby the sleeve lifts slowly during the initial portion of its opening movement, thus admitting very little additional fuel mixture, and

preventing choking of the engine. On the other hand, once the critical point at which choking might take place is passed, the sleeve lifts more freely and readily admits an increased supply of mixture to the engine:

No. 167,846, by A. J. H. Elverson, is a multi-jet carburetter, in which special provision is made for easy starting, and

for vaporization of the fuel. The float chamber is an annular one, surrounding the mixing chamber, while between the two is a jacket or passage, which is heated by exhaust gas. The jets are disposed round the carburetter, which they enter at an angle. Actually, they all of them open inWii,"narrow channel formed in the wall orthe induction pipe, from which it is separated by a lining.of wire gauze. This channel is so arranged with respect to the jets that there is always a small quantity of fuel left in the lower ' portion of it, which fuel keeps the gauze moist, so that starting is easy.

Another carburetter improvement is described by C. G. F. Carver in No. 167,879. It' has reference to means for heating or vaporizing the petrol or other liquid fuel employed, For the purpose gauze discs of high resistance wire are employed. These are heated by an electric current, and the combustible mixture is drawn through them. Such an arrangement, however, would not be

safe for use with petrol, Or other light hydrocarbon fuels, owing to the possibility of pre-ignition. This particular invention comprises a means of obviating any danger from this source, and for the purpose other gauze screens are arranged in such a manner that they cut off that portion of the fuel which is passing through the electrically heated screen or screens, J. P. Proud fits a carburetter with thermostatic control, the said control consisting of a hermetically sealed capsule containing a substance sensitive to changes of temperature. The specification is numbered 167,828.

The carburetter which is described in No. 167,800, by L. A. De Becker' is suitable for the carburation of paraffin and similar fuels, as well as petrol. The invention really relates to a device for heating the jets electrically.

Another invention is described by Essex Motors in specification No. 145,427, The carburetter'is fitted with a suctionoperating sleeve, which, as it rises, increases the area of the opening for the passage of air to the carburetter.

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Organisations: Patent Office

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