Four-cycle internal combustion engines in which a volume of air unmixed with combustible is caused to pass through the working cylinder of the engine or the combustion-chamber thereof at any time between the end of the working stroke and the beginning of the next following charging stroke, whereby to secure a more complete removal of the burned gases of the previous charge from the cylinder and combustion-chamber, so that the successive charges will be unmixed with residual burned gases from a previous charge. The scavenging action
may take place before or after or be simultaneous with the regular exhaust stroke of the engine. In the engines in this subclass a complete charge comprising all the ingredients necessary to form a combustible mixture enters the cylinder upon distinct charging stroke, the air supplied for the purpose of scavenging, not being necessary to form or complete the following charge.
(1) Note. Engines frequently described as scavenging engines and in which a volume of air is caused to pass through the working cylinder and combustion-chamber for the same purpose as in this subclass, but in which a portion of such air is necessary to complete the following charge, are classified in this class, subclass 69. In subclass 76, the engine begins its suction-stroke with air in the clearance space only, while in engines in subclass 69, the engine begins it compression-stroke with a considerable volume of air in the cylinder thereof, to which a combustible is supplied to complete the charge.
SEE OR SEARCH THIS CLASS, SUBCLASS:
64, and 69, for six-cycle two-cycle Separate Air and Gas Pumps.
