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• SOME NOVEL ENGINES.

15th February 1921
Page 32
Page 32, 15th February 1921 — • SOME NOVEL ENGINES.
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Which of the following most accurately describes the problem?

A Résumé of Recently Published Patents.

A crankshaft has always been considered, hitherto, to be more or less essential to a motorcar engine, whether it be of the two-stroko or four-stroke internal-combustion type, or even if it should happen to be a steam-engine. This, however, is clearly not the opinion of N.V. Fletcher, for be describes in specification No. 156013 an engine which has no crankshaft, the place of that .component being taken by a camshaft. The engine is of' the two-stroke type, and includes a compressor as one of its essential components. The general outlines of the invention will he appreciated from the following description of the engine, which is illustrated herewith. On a crankcase of more or less familiar outlines are mounted two power cylinders, disposed radially, forming what is popularly known as a V type engine. Pistons, which are mainly of the usual form, are used, but there are no connecting rods, the inner ends of the pistons being coni cally shaped and so formed that they provide suitable bearings for the pins of cam rollers such as are frequently used at the lower ends of valve tappets. The tops of the pistons are screwed to receive fixed guide rods, and these extend through the cylinder heads, suitable provision being made to prevent leakage of the gases through the hole which accommodates the guide rod.

Between the two power cylinders is the compressor cylinder. The latter is of much smaller capacity than either of the former ; its piston is of similar type, but in this case no guide rod is considered necessary. Although it would appear from the drawing that the compressor cylinder is in line with the power cylinders, such is not the case, as it is actually' set back to one side of the plane of main cylinders for a reason which will hereafter be apparent.

The rollers on the inner ends of the main pistons bear upon suitable earns on the main camshaft, which., as we have stated, is utilized instead of a crankshaft. The shape of the cams need not be described; it is apparent in the drawing B28

which ,we reproduce from the patent specification. The faces are so designed as to be the most effective for the duty which they are called upon to perform;. one, utilized on the outward stroke of the piston, being for compression purposes, the otaier, an as to rcceive and transmit with the best effect the power produce' as the result of the explosion ef the gases.

Parallel with the main cam and mounted on the same shaft is the sub sidiary arrangement for driving the compressor. The position of these cams determines the position of the compressor cylinder. The inlet to the compressor is a small automatic valve in the cylinder bead, the outlet is through a port in the cylinder wall, the compressed air being delivered into a pipe fitted with a nonreturn valve and serving as a receiver. The compressed air and combustible mixture are admitted to the power cylinders in the usual way by a mechanically operated poppet valve. Exhaust takes place through apertures in the walls of each main cylinder, these apertures being uncovered when the piston has nearly reached the end of its working stroke.

The operation of the engine is quite simple, and calls for but little explanation. Presumably the inlet port to the compressor communicates with the carburetter and, on a preliminary, turn of the starting handle:a cYlinderfull of this is drawn into the compressor, compressed and delivered to the receiving pipes. At the right moment the induction valve of a power cylinder opens and this coinpressed charge is transferred to that cylinder... The charge is farther compressed by movement of the'Piston in the main power cylinder, is fired in the usual way by electric ignition, and drives the engine shaft through the medium of the proper cam.

Other Patents of Interest.

Another engine of unusual type is described, in specification No. 155892 by C. M. Shaw. In this the connecting rods of the main pistons are not coupled direct to the crankshaft. They operate upon what may be described as a rocking lever, and the power is transmitted from the latter to the engine crankshaft by an ordinary connecting rod. In the drawings which accompany the specification a four-cylinder engine is illustrated. The rocking lever is square. There are two ylinders operating upon one upper corner of the rockbfg lever, the ,other two cylinders are coupled through their connecting reds to the diagonally opposite lower corner ; the other lower corner accommodates the small end of the main connecting rod, while the corner still remaining carries a weight which counterbalances that of the main connecting rod. It is mainly as regards the arrangement of this rocking lever, and in particular because of the provision of suitable balancing, that this patent appears to be claimed.

The Birmingham and Midland Motor Omnibus Co., Ltd., describe an improved construction of rear spring, particularly adapted for use in connection with those vehicles in which the rear spring has to sustain the torque and thrust of the rear axle as well as to absorb road shocks. Their improvement, as described by the specification, consists in the application of an additional plate above the top leaf of the main spring, securely clamped thereto, and fastened to the axle. The patent specification is No. 156027.

A rather interesting detail of gearbox conetruction is illustrated herewith. It appears in connection with specification No. 145769 . by the Daimler Motoren Gesellschaft, and its object is to reduce the overall lengths of the shaft, etc., of that important ecruponent. It will be seen that the sliding gears are disposed in pains so that a small one is contiguous to a large one. The latter are se shaped that the former can slide into their mteriors and in this manner the width of a couple of gears is economized in the length of the box.

J. B. D. L. Chardard describes a particular method of constructing a radiator in specification No. 152297. No. 155938 by S. P. Bevan describes a tank adapted for conveniently transporting fuel oil or lubricating oil.

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