CONSTANT COMPRESSION AT ALL THROTTLE ,POSITIONS.
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A Résumé of Recently Published Patent Specifications.
A N interesting invention is described in specification No. 276,332, by Marcel A. Violet, of Courbeveie, France. The specification points out that it is an advantage to keep the compression of an internal-combustion engine constant, no matter in what position the throttle may be. In such engines the• compression is usually 'arranged so that the best results are obtained when a fully open throttle is in operation ;. consequently, when the throttle is partially.
closed, the compression . drops. The object of the present invention is to maintain a pre-arranged degree of compression, no matter in what position the throttle may be, open or partly' closed.
In the construction described, the cylinder is provided with the usual inlet and exhaust valves, but at the Part of the cylinder which is exposed when the piston is near its lowest position there is a port leading to a chamber where exhaust gases can be stored. A cock (A) is provided which can be regulated by hand or may be connected to the throttle (B). The functioning of the engine is as follows :—The piston at its lowest position on the exhaust
stroke uncovers a port which allows some of the gases to escape through She port and to remain in the storage chamber, the main body of the exhaust passing out by means of the usual exhaust valve. On the suction stroke, should the throttle be fully open, the cylinder can receive its full charge of mixture in the usual way, but should the throttle be partly closed a restriction will be placed to a full charge entering the cylinder, consequently a partial vacuum will be in the cylinder when the piston nears the bottom of its stroke, which will cause a certain amount of burnt gas to enter the Cylinder to make up a full charge. It is claimed that this amount of burnt gas does not mingle with the mixture drawn in during the previous part of . the stroke, but remains as a lower stratum, forming a cushion to relieve the force of the explosion. It is also claimed that the inriishing burnt gas has the effect of clearing the top of the piston from any carbon deposit.
When starting, the cock (A) is closed, so that conditions are normal, as owing to the slow speed of an engine at that time there is nothing to prevent the cylinder filling completely with mixture. A valve (C) may be fitted, by means of which the amount of burnt gas which returns to the cyliuder can be regulated.