US1015217A - Internal-combustion engine. - Google Patents

Description

W. J. STILL.

INTERNAL COMBUSTION ENGINE. APPLIOATI'ON FILED APR.'14, 1911.

1,015,217. I PatentedJan.16,l912..

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' UNITED STATES PATENT OFFICE.

WILLIAM JOSEPH STILL, OF SOUTHALL, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

Specification of Letters Patent.

Patented J an. 16, 1912.

Application filed April 14, 1911. Serial No. 621,165.

provide for the more effective scavenging of internal combustion engines.

It has been observed by experiment that in engines having a ring of ports at one end of the cylinder acting as exhaust ports and another ring of ports at the opposite-end acting as scavenging air inlets which are uncovered by the piston that if the heacLof the latter which co-acts with the ports be suitably concave and presents no irregularities the rush of air which enters by the ports occurs in a uniform mass which does not mingle with the products of combustion but acts as a compact mass to expel or push them out of the-ports at the other end of the cylinder. There being no eddies less air is required and more complete scavenging is insured if this feature is utilized.

This invention consists therefore in employing a piston with a concave head free from such projection or the like as can act to break up the gas stream in an engine of the character indicated for this purpose. The degree of concavity which is found to yield the best results is a radius equal to the bore of the cylinder.

The accompanying figure shows diagrammatically one method of carrying the invention into effect as applied to an engine in which opposed pistons reciprocate in a cylinder.

The cylinder casting a is provided with three rings of ports opening into the cylinder 9 which comprise b the exhaust ports, 0 the combustible inlet ports and (Z the scavenging air inlets. The piston c which coacts with the latter is provided with a concaved face f the radius of curvature of which is equal to the bore of the cylinder 9. In this case as soon as the piston c uncovers the ring of ports 01 air will rush in to effect scavenging but owing to the form of the piston the same will not break up into eddies or swirl around but will advance as a more or less uniform mass to expel the products of combustion from the exhaust ports Z). The piston h is also shown as having a concaved head but this feature is not essential and this piston may have any usual form.

It will be understood that in the form described the entry of the combustible through the ports 0 is delayed in any suitable way until after the ports d are just covered again by the piston e.

It will be understood that it is of importance to have the largest port area possible and that it is also of importance to have a symmetrical port arrangement which features are most easily attained by a port arrangement of the nature above described. It will be understood however that the ports are not necessarily exactly symmetrical or of any particular form provided that they do not create such disturbance of the flow of gas that the concave form of the piston is not able to produce any substantial effect.

The admission ports should preferably be made without irregularities of surface such as will deflect the inflowing gas from the desired direction.

Having now described my invention what I claim as new and desire to secure by Letters Patent is An internal combustion engine having a cylinder with inlet ports substantiallyannularly symmetrically disposed around the same and a piston with concave head adapted to cover and uncover the said ports the radius of curvature of said concave head being about equal to the bore of the cylinder; as set forth.

In testimony whereof, I affix my signature in presence of two witnesses.

WILLIAM JOSEPH STILL. VVitnes'ses CYRIL F. L. NURSEY, P. A. OUTHWAITE.

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