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A Petrol Injecting Unit

16th July 1954, Page 62
16th July 1954
Page 62
Page 62, 16th July 1954 — A Petrol Injecting Unit
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THE subject of petrol injection

appears' to be receiving more attention on the Continent than in this country, and patent No. 710,213 (Ustav Pro Vyzkum Motorvych Vozidel, Praha, Czechoslovakia) shows an improved type of injection nozzle. The aim is to enable a simple gear-type pump to be used instead of one of the more expensive high-pressure plunger type.

With a gear pump, it has been found that its pressure drops with a decrease in speed so that the injected droplets become large and will not readily vaporize. The aim of the injector shown is to cOrrect this defect.

The injector (1) is provided with a jet (2) which lines up with a bore (3) leading to the intake passage (4). A clearance space (5) in-the shape of a disc is open to the atmosphere via bore 6.

In operation, the issuing fuel is mixed with a little air in the clearance space and is blown into the intake in the form of a rich mist which will rapidly vaporize at all engine speeds.

ROTATING POPPET VALVES

POPPET valves work better if they I slowly turn during use and most in fact do so. It is however not certain, and a scheme for definitely inducing rotation is shown in patent No. 710,512

13!. Thompson Products Inc., Cleveland, Ohio, U.S.A.

The drawing shows the device under load. Between the spring and its abutment is an assembly comprising an upper ring (1) and a lower one (2). Between the rings is a pair of flat, spring washers which normally clear a set of balls (3). Under load, as shown, the spring washers are dished and heavily load the balls.

The ball groove is not a complete A36 circle but consists of six arcuate slots, each containing a ball. The bottoms of the slots slope downhill to their midpoints. This means that when a load is applied, the balls roll slightly towards the middle of the slots and thus turn the spring assembly, and through that, the valve. When the load is relieved, small coil-springs trapped in the slots return the balls uphill.

A NEW WAY OF FIXING CYLINDERS

AN unusual method of securing cylinders to a crankcase is described in patent No. 709,894 (General Motors Corp., Detroit, Michikan, U.S.A.).

In this scheme, the bottom of the cylinder is provided with a narrow rim and a similar rim is machined on the crankcase. In assembly, the two rims meet and are pulled tightly together by an encircling clamp-ring.

The drawing shows the assembly in which 1 is the clamp ring which consists of two semi-circular members pulled together by bolts (2). The rims and the clamp arc slightly tapered so as to exert a contracting force.

The pulling-down action also traps the liner between an upper gasket ring (3) and a saucered spring-steel washer (4). This arrangement permits the liner to expand freely when heated.

IMPROVING THE EFFICIENCY OF POPPET VALVES

ALTHOUGH the normal poppet valve is extremely good in respect of its self-sealing properties, its layout usually calls for a sharp bend in the port. In the case of inlet ports, this is a definite disadvantage because the ideal shape is a dead straight bore.

To achieve this end is the aim of an improved scheme shown in patent No. 710,073 (A. Butterworth, 7 Grove Gardens, Frimley, Surrey). The scheme is intended mainly for racing engines, but the search for higher efficiency is common to all vehicle designers.

The valve, instead of being reciprocated, is arranged to be swung on a hinge pin (1). This carries a curved arm of aerofoil section to which the salve-head is attached. In the open

position, as shown in chain line at 2, the valve-head has left the major part of the passage unobstructed so that a straight-through blast of gas can reach the cylinder.

Such obstruction as is created is claimed to be beneficial in that it creates a swirl inside the cylinder. •The cross-section of the passage changes gradually from a circle to an ellipse as indicated at point 3.

RUBBER-CUSHIONED CLUTCH-PLATE

FROM Dunlop Rubber Co., Ltd., 1 Albany Street, London, NAVA, comes patent No. 709,115 which discloses a design for a torsionally resilient clutch plate. Between the hub and the plate is a hexagonal coupling spaced apart by a rubber filling; this can distort under load and so absorb sudden shocks.

A DEFLECTOR FOR OIL ENGINE COMBUSTION HEADS

Pdistribute the flaming charge from a precombustion chamber uniformly into the cylinder space, is the purpose of a modification shown in patent No. 710,094. (Daimler-Benz A.G., Stuttgart-Untertfirkheim, Ger

many). Although deflectors on the piston crown have been used for this purpose, they get very hot and set up thermal stresses in the piston. The present scheme avoids this, The drawing shows part of a cylinder-head in which 1 is the precombustion chamber and 2 the injector bore. Attached to the neck of the outlet by narrow webs is a disc-shaped deflector This turns the flaming jet into a flat sheet of flame which penetrates to all parts of the main air charge compressed in the piston recess (4). The resulting uniform fuel distribution is said to enable a low consumption to be achieved.


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