The Latest Swash-plate Engine
Page 52
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AT frequent intervals a patent appears disclosing a new design of swash-plate engine, thus showing that there may yet be a rival to the usual crankshaft type. Such a design is shown in patent No. 442,126 (void) by H. Alfaro, 308, Hayden Buildings, Cambridge, Mass., U.S.A. The virtues claimed for this type arc lightness, low cost, and small frontal area, the last feature rendering it suitable for
aircraft. Although it may be made to operate on the four-stroke cycle, • the design illustrated is a two-stroke, and works on the oil-engine principle.
In the accompanying drawing, the central power shaft carries two camplates (6 and 7) which impart reciprocating motion to the pistons, via the medium of rollers (4), a small hookover lug (5) ensuring the return. There are two pistons per cylinder, with a common central combustion chamber to each pair. The fuel injectors are supplied by a series of individual pumps (8) ; these are also operated by the cam-plites, but obviously not in the sequence shown in the drawings. The engine may also run on petrol, sparking .plhgs being shown at 2.
The sequence of operations is the usual oil.-engine cycle, compressed air entering at the port (3), whilst the exhaust gases pass out of the ports (1).
Hydraulic-epicyclic Developments.
A COMBINATION of torque con
verter and epicyclic gear is ,described in patent No. 442,363 by R. P. Fraser, A.R.C.S., 20, Margravine Gardens, London, W.6. This inventor claims that the speed-torque curve of this gear covers a greater range than that usually obtained from the usual type of fluid gear. Tte drawing shows diagrammatically
the epicyclic arrangement, in which the engine shaft (7) is connected to the impeller (2) of the hydraulic gear, and to the sun-wheel (6) of the epicyclic system. The driven blades of the gear are fixed to the planet carrier (3) of the gear, and the guide or reaction vanes (8) are connected with the outer annulus (5), forming also the power output shaft. A free wheel (4) is interposed to allow reverse running.
Reducing the III-effects of High Compression.
I T is well known that a high compres sion will result in improved thermal efficiency, but before the optimum value can be reached' other factors, such as detonation and mechanical stresses, demand consideration. To obtain the full advantages of high corn.
B42 pression, and yet keep the maximum explosion pressure within certain limits, is the object of patent No. 441,858 by P. Will:len:tun, 4, Chartfield Avenue, London, S.W.15.
This inventor proposes to locate a small-volurtte chamber adjacent to the combustion space in the cylinder head, for the purpose of temporarily receiving some portion of the explosion charge, this to be returned to the cylinder at a lower point in the stroke. The drawing shows one form of construction, in which the relief chamber (1) is connected to the cylinder (3) by two valve-controlled passages. The entrance valve (4) is springloaded and operates in a manner similar to a safety valve, admitting gas when the cylinder pressure is high. As the piston descends, and the cylinder pressure falls, the exit valve (2) , which is closed by a very light spring, opens and returns the high-pressure gas to the cylinder.
A New French Injection Nozzle.
AN attempt to make an injector embodying the features of both open and spring-closed types is disclosed in patent No. 441,911 by Societe Proveneale de Constructions Aeronau
tiques, 3, rue de la Baume, Paris. The object of the invention is to provide a nozzle that will meet the requirements of both light and full loads, at the same time preventing excessive pressures being set up in the pump. The drawing is a section of the .injector, and shows an orifice (1) under the control of the spring-loaded -needle, whilst a second orifice (2) remains open at all times to the fuel supply.
In action, the small quantity of fuel used for light loads is injected through the open orifice ; at heavier loads, however, this is unable to deal with the increased supply, and the spring valve is forced open.
Pump-plunger Design.
THE design of injection-pump plunger shown in patent No. 442,435 by A. H. Thomas and Bryce, Ltd., Kelvin Works, Hackbridge, Surrey, is directed towards decreasing the manufacturing difficulties, at the same time providing a more efficient pump. The specification states that hollow plungers,
as commonly used, are sometimes unsatisfactory owing to the difficulty of removing hardening scale from the interior bore ; also the machining of the barrel portion can be considerably simplified if the milling .operation be replaced by a simple drilling.
The drawing shows the improved design in two positions, the plunger at the top of the stroke, and at the bottom. The ports in the barrel coinprise a Supply port (1) and a release port (2); these are plain drillings, the control being given by a single-turn helical groove machined in the plunger. It is further claimed that the injection period commences with extreme rapidity, owing to the fact that the plunger is in rapid motion at the moment of closing the supply port (1).