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A NEW CLAUDEL—HOBSON CARBURETTER.

10th July 1923, Page 22
10th July 1923
Page 22
Page 22, 10th July 1923 — A NEW CLAUDEL—HOBSON CARBURETTER.
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An Alteration in Design Which Improves the Acceleration and the Power at Full Throttle.

T""power-jet' models Of the well-known Claudel-Hobson carburetter have been designed with the object of improving the ,power at fuli throttle without increasing the consumption at other throttle openings ; at the same time the acceleration of the engine is improved. The construction of these . models is such that the settings for idling, normal running, and fun power are independently carried out, so that any one can be adjusted without affecting the others; the tuning process is thereby simplified..

It is a.well-known fact that a carburetter can be tuned in two ways: to give the weak mixture necessary for low consumption, or to give the strong mixture essential to the development of full

power. It is claimed that this new design is so arranged that an econemical mixture is supplied throughout the range of throttle opening until full throttle is reached ; at this point the mixture is strengthened, so that the full engine power becomes available when required. • Referring to the sectional view, it will be seen that the petrol passes from the float chamber through a duct (A) to three concentric tubes (B, C, and 0), which are filled to a level dependent on the adjustment of the needle and float. When the engine is idling, petrel is sucked through the fine hole (E) contained in the central tube, and mixes with air entering through holes at F. The mixture is then drawn through the by-pass to the engine. The air screw (S) and theby-pass adjusting screw (T) remain as in the older pas.

When the throttle is opened, air passes up the duct (G) to the annular space (H), and thence through the holes (J) and outer tube (C), forcing petrol out of the tube and through the holes, a rich mixture of air and finely atomized fuel being obtained. This mixture passes out through the holes (K) and mixes -with the main air supply, which entera at LI All the petrol passes through the hole in the plug (IV): so that it is -upon the size of this part that the strength of the mixture ultimately depends. For convenience in reference M is called the main jet, and the tube (B) (which contains the plug R) is called the

slow-running jet. •

When the throttle is opened the reserve of petrol in the diffuser tubes enables the engine to accelerate rapidly. At the same time the level of the petrol falls (in the tube) until a sufficient number of depression holes, such as J., are uncovered to establish a. balance --of pressure. The proportion and number of the depression hales are adjusted so as to give the correct mixture strength for economical running. The power jet is independent of the diffuser, and is shown on the left of the diffuser in the first. illustration. When the throttle is opened wide, the suction takes effect on the petrol in this jet, and the strength of the mixture is increased. In this .way the maximum.power is obtained at full throttle without sacrificing economy at other throttle openings, a result which, as previously explained, cannot usually be obtained.

In addition to the vertical type shown, horizontal types are being made, which operates on the same principle. These

interesting carburetters are inanufac .

tureti by H. M. Hobson, Ltd., 29, Vaux

hall Bridge Road. II,ondon, S.W.1.

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