REVOLUTIONARY INVENTION

Hokitika Guardian, 4 July 1931, Page 6

REVOLUTIONARY INVENTION

DUPLEX PISTON VALVE

IN.Z. COMPANY’S BRIGHT PROSPECTS.

A R-Ei.VIAIRKA.BIiE MACHINE.

LONDON, April 21

A number of New Zealanders who have had no return for their £15,000 of capital for a number of years should be very happy people in the not distant future. They are financially concerned with an invention which should, without exaggeration of any kind, revolutionise internal combustion engines.

The completed model stands jn a railway arch belonging to an engineering firm .somewhere in (London. The representatives of the company—the Duplex Piston Valve (N.Z.), Ltd.—have, been in London for three years. Four separate engines Tiave been built and tried out. As the principal inventor expresses it, “They have made a thorough search tor niggers in the wood. They have found them in abundance. Difficulties have been faced and overcome. Each stage of the invention has been patented, with the idea of preventing any subsequent dispute. These patents have been expensive, and they have not been obtained expeditiously. Changes have had to be made an the design until now the completed engine is such that, with all its efficiency, the manufacturers who take it up will not need to make very expensive alterations in their plant and tools. “The valve can be produced by relatively unskilled labour on any ordinary tool equipment,” as Professor A. VI. Low, the eminent consulting engineer and research physicist, remarks.

It lias been my privilege to examine a number of new machines and inventions for which a great future was promised. The talking oh-tnro, for instance, but even that in the early days was a poor thing. Other excellent inventions by New Zealanders have not gone ahead because those who should take them up would not themselves make much money out of them. This Duplex Valve is on quite another foo'imr. Tb" company's representatives are wise to keen silent in this country for the present. A machine that can so greatly reduce running costs, and so enormously increase power and efficiency with the same amount of fuel is a thing to be desired. If the valve is to be fitted to even .1 per cent, of the engines of the future—and certainly puts the present type of valve entirely out of date—the 'New Zealand company has wonderful prospects. It was a. cold, damp morning yesterday. 'The new model has been motionless for three days. Three revolutions of the handle started the engine. In a few moments it was going 2000 revolutions a minute, with a medium six horse power load on in the shape of a fan. 'L’he exhaust pipe near to the cylinder could he touched for a second or two, and the exhaust gases at the end of the pipe were quite cool. Complete combustion had been acquired. The engine is wonderfully silent.

A ’MYSTERIOUS TWIST. The new .valve does away with the poppet valves. Instead of these there is a solid piston of steel about a toot in length. By an ingenious but simple device, this is made to go backwards and forwards in its sleeve. But at the same time it is subjected to a rotavy motion as well. A large port through the piston allows tin* explosive mixture to go .into the main cylinder at. a speed quite unattainable with the poppet valves.. Moreover, the gas is subjected to some mysterious twist, and arrives •in uue cylinder in finer particles than it does in present machines. According to the technical phrase, there is no “wire-drawing effect.” In ordinary language, this means that the gas mixture finds its place in the cylinder comfortably and without stress and " strain and friction in an infinitesimal fraction of time. The explosion takes place, and because of the fineness of the particles there .is complete combustion. As the

main cylinder begins to rise to eject the burnt gases, an aperture, through the piston valve is exposed to allow them to go out—again without stress and strain. At the outlet there is again the spiral effect on the exhaust gases, and this probably has the ellect of hastening them along the exhaust pipe. One other secret of the machine is this : The piston valve in. its reciprocating motion makes what may he described as a “comparative pause” at each end of its stroke. It is just at these times that the ports are open to the full, for the intake on the one hand and the outlet of gases on the other hand.

PROFESSOR LOW’S REPORT. Professor Low, in the course of his favourable report on the demonstration engine which has been designed in accordance with the company's patents, says : “The speed at which the port openings are obtained give a torque curve which should compare more than favourably with any multi-cylinder engine of comparable size and fuel consumption. “I consider that the main principle of the design could be applied to motors of the Diesel type without any appreciable increase in cost over those of poppet valve design.

FOR AYIATTON USE. “During a brief running test it was to be observed that although no special arrangements were made to ensure satisfactory carburetion at- varying .engine temperatures there was a complete lack of the inlet condensation which has so

often mitigated against the success oi the “piston or sleeve’ engine. For this reason it would appear that the heavier classes of oils could be used in a Duplex motor designed under the patents. This is worthy of note in view of the possible application of the design to colonial and aviation use.

“Although the. experimental motor is ol the single cylinder type without any real balancing precautions, the running was quite exceptional over a wide range of speeds and a degree of silence was maintained which could not be equalled by any ordinary engine.

“In mv opinion, it would be possible to design a commerical type of engine under the principles of this invention which would maintain its tune over long periods, would be silent under conditions of rather rough manufacture, and which would be able to compete most satisfactorily with existing design. “] have formed a high opinion of the commercial possibilities of this engine.”

ROLLS-ROYCE RESULTS.' It .neecls little imagination to see the advantages of this new invention. Ihe exhaust gases of some of the finest aeroplane engines, for instance, are so hot as to be able to raise the metals to a white heat. The finest metals have been produced to resist this heat. With the Duplex valve installed the hand could be held in the path of the exhaust gases at a very short distance D'om the outlet port, -veil at the highest speeds no flame is emitted. 'lhe valve will need" no more attention than other parts of the motor engine. Jt will remain constant throughout the life of the engine, requiring no adjustment. Its constructional cost will be very little, if at all, higher than that of the ordinary poppet valve type and much less than that of the sleeve valve. The official graphs prove that under load the engine develops power and M.E.P. curves of surprising figures, and this in addition to notable silence, lack of vibration, and economy. The rating of a single cylinder, according to th<‘ Royal Automobile Club, is officially /put down at 4.9 h.p. With the Duplex piston valve 11 h.p. is obtained. In short, it is claimed, and apparently with justification, that by thin troduction of this New Zealand invention manufacturers will be able tq get “Rolls-Royce results at mass-produc-tion costs.”

The invention was conceived from a small idea originating in -New Zealand; it has been developed ami perfected in London with New Zealand capital. Therefore those responsible are desirous that . ,ew Zealand and the whole British Empire shall have the first, opportunity of knowing of its success. Needless to sav, the American rights could easily have been obtained, but New Zealanders are to be given the first chance, of taking it up and benefiting by it. ihe British Empire comes before other countries because those who have been entrusted with the development of the idea are New Zealanders by adoption and are British by birth. We shall certainly hear more of this remarkable Duplex piston valve before many months have passed.