ALTERNATIVE FORM OF FORCED INDUCTION.
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A Résumé of Recently Published Specifications.
T"principle which underlies the invention which is described in specification No. 194,697, by-0 W. Holt, may be said to be alternative to* forced induction as •exemplified in the cars which competed this month for the Grand Prix.. In the form in which this inventor patents it, the invention embodies an internal-combustion engine in which air, • or a mixture of air and hydrocarbon is first compressed and introduced into a• receiver which is water-cooled to such an extent that the heat of compression is for the most part renioved. Subsequently, when the mixture-is passed to the working 'cylinder of the engine, in the course of which it is expanded down to atmospheric pressure, its • temperature drops to zero C., • or even below.
As shown in one of our drawings, which is taken from the patent specification, the engine and compressor are built as a unit. The receiver for the 'compressed gas is embodied in the same casting, and contained within the water jacket of the engine. The air is corn.; pressed to a pressure which is determined according to the means available for cooling it, and the temperature to which it is desired that it shall fall on admission into the working cylinder: Eight,atmospheres is mentioned as being • 'a, suitable pressure and, in an example quoted, it is demonstrated that air at that pressure and at 60 degrees C.
on expansion down to atmospheric pressure, have a temperature of 84 degrees C. If this gas enters the cylinder, even supposing that it blends as little as possible with such hot air and other gases left within the cylinder, it 'would still derive a considerable amount of heat from contact with the walls of the cylinder and the head of the piston, and its temperature would probably rise to approximately 10 degrees C.
As a result of this low temperature of entry, the ratio of compression within the engine could safely be increased to 10, without fear of pre-ignition, as against an orthodox figure of 4.5. .
In the engine -described in the specification, the working cycle is the twostroke. There are, in orthodox positions in the wall of the cylinder, an outlet for the exhaust gases and an inlet for air from the crankcase. As the piston descends, it uncovers these ports, allowing the exhaust to make its exit, and the crankcase-compressed air to enter and help to drive out the burnt gases. To ensure more effective scavenging, an additional engine-operated valve is provided at the top of the cylinder, and the air from the crankcase continues to drive out the products of combustion through this valve during about half the upstroke of the piston. Before this supplement' ary valve closes, the inlet valve to the cylinder, from the receiver into which the main charge is compressed, is opened, and the charge, propelled down,.wards on to the top of the rising piston, forms a rapidly deepening layer of cool gas which is presumed to fill the cylinder by the time the upper scavenging valve has closed. The means for opening the main inlet valve are so contrived that the time of opening is dependent on the operation of the scavenging•valve.
B48 Another form of engine, utilizing the same principle, but making provision for the storage of a larger quantity of the compressed mixture, a_nd embodying modifications in the' valve gearing to enable full advantage to be taken of the existence of that increased volume, is described by the same inventor in specification No. 195,057.
Other Patents of Interest.
ETTORE BUGATTI describes a carbu retter in specification No. 205,088, which has a central diffuser chamber, in shape like an inverted cup, and containing a transverse venturi tube which is the diffuser proper. The jet is located in the tube, slightly out of centre. and nearer the inlet end. The throttle valve is another inverted cup, which surreunds the diffuser chamber. It has two circular holes which, when the valve is fully opened, register with the ends of the diffuser tube, 49 that, as the valve 'is partially closed, the aniotint of open; ing at one end of that lithe corresponds to that at the other.
IN the multi-purpese body which is scribed in specification No. 207,524, by A. L. Negre, the low sides of a plain body are supplemented by .a system of levers, which carry extension sides of wire mesh. By manipulation of the levers the sides can be made to assume a variety of positions, according to the purpose for which the vehicle is at thp moment required.
DIFFERENTIAL locking mechanism and means for driving a winding drum are embodied in the construction which is described in specification No. 218,374, by Armstrong Siddeley Motors, Ltd. The gearing thus patented is intended mainly for use on heavy tractors of the chain-track type.
SOME further particulars of the con struction of the Sentinel steam tractor are disclosed in specification No. 218,376, by S. E. Alley. The feature patented is the arrangement of the engine under the chassis frame and, at the same time, outside the wheelbase.
COLLECTION of household refuse is facilitated by the means which are patented in specification No. 218,485, by T. C. Oughton and another. The bins are lifted on to a platform at the rear of the vehicle, and subsequently raised and emptied into the body by gearing which is driven from the engine. The same mechanism opens and closes a lid on the body in proper time with the operations of tilting.
TAXIMETER rrilschanism and its im provement are the subjects of patent specification No. 196,283, the patentee being the Soc. Parisienne de Micanique Generale. The improvement described relates to the method of transforming the regular rotation of a worm, driven from some moving part of the chassis, into that intermittent motion which is familiar to all users of taxicabs, and which makes itself evident in the jerky movement of the figures on the fare register. In this particular design a pair of parallel levers and two pawls are used to provide the peculiar movement which is required.
WHEEL extraction is the subject of patent specification No. 216,352, by J. A. Ryley. He has patented a device to facilitate the removal of the hubs of detachable wheels, and particularly those of the type in which bolts are used to secure the wheel to the hub and brake drum. He uses the bolts for the support of his wheel extractor, thus avoiding the risk of damaging the rim of a brake drum which might occur were that rim used as a means of operating the extractor. His device is a manyarmed spider.