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Page:Popular Science Monthly Volume 90.djvu/861

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Eliminating Automobile Valve Trouble

Valves made of pure carbon are self-lubricating

���ALL valve grinding, trouble with weak r\ valve springs and loss of power through improper seating of valves would be eliminated if the motors were fitted with the carbon rotary valve shown in the accompany- ing illustrations. It is made of pure carbon in the shape of a cone with the apex cut off and is run small end down in a steel seat placed be- tween the cur\-- ature of two or more adjacent cylinders. It is carried on a ver- tical shaft re- volved by a pair of bevel gears driven off the en- gine crank-shaft. Two Boston men are the inventors.

Carbon is one of the best lubricants known and has great heat resisting properties, so that the valve is practically self-lubricated and is yet able to withstand the heat of the ex- haust gases without warping and sticking in its seat, a trouble heretofore always ex- perienced to some ex- tent with metal- against-metal rotar\' valves.

The illustration shows a four-cylinder motor with its cylin- ders cast in pairs and a valve for each pair.

��A four-cylinder motor with the cylinders cast in pairs. There is a valve for each pair

The two rectangular intake and exhaust ports in the ciiTved sides of the valve

��Exhaust port

��Exhaust manifold

���From carbwreter

Squared valve stern

A cross-sectional view showing the construction of the valves and their relation to the engine cylinder

��As shown in the draw ings, the valve has two rectangular ports cut in its curved sides at points 20 degrees apart. A passageway is cut from one of

��these ports to the large top of the valve. A similar passage is cut from the other port to the bottom of the valve, the passages being on the same side of the valve as the

port in each case. The open- ing in the top serves as the ex- haust port and that in the bot- tom as the in- take port.

At the begin- ning and during the suction stroke of the motor, the valve is rotated in its seat so that the intake port in the \- a 1 V e is made to coin- cide with the jx)rt in the valve seat which opens into a pas- sage leading di- rectly into the head of the cylinder. The gas passes up through the crescent -shaped opening in the bottom of the valv'e, through the coin- ciding ports in valve and seat and thence through the passage leading to the cylinder where it is ex- ploded in the usual man- ner. Then as the valve is rotated at half the sj>eed of the motor, the latter has its compression and firing strokes before the valve has made one- half a revolution and the exhaust port of the latter is brought opposite the valve seat port to permit the burnt gases to pass through the valve and up into the exhaust manifold. The following half revolution of the v'alve takes care of the second cylinder.


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