Unofficial Alpha Subclasses: R PE A B BA PD S V VA VS VB VC VD W WA WV SP EM
DEFINITION
Classification: 123/65
Internal-combustion engines having a single single-acting working cylinder and a single working piston reciprocating therein and having suitable means for supplying a combustible mixture thereto, such engines working on the two-stroke cycle and not coming within the definitions of the following subclasses of two-cycle engines. Internal-combustion engines are said to work upon the two-stroke cycle when a combustible mixture under pressure materially greater than atmospheric pressure is burned and the resulting products of combustion allowed to expand within the working cylinder upon every second stroke of the working piston of the engine. The means for supplying the combustible mixture to the engine ordinarily includes a pump operated by and in unison therewith, which pump and engine are generally inseparable
without destroying the identity of the device as a whole. In the engines occurring in two-cycle subclasses a combustible mixture is supplied to the working cylinder and burned therein under pressure upon each second stroke of the working piston, and such mixture after having been supplied to the working cylinder at a pressure not necessarily greater than is sufficient to insure its flow there into may be recompressed therein by the working piston or by the working and pump pistons acting together before ignition and the beginning of the working stroke, which is the more ordinary mode of operation, or the mixture may be supplied to the working cylinder after the beginning of the working stroke and at the maximum pressure under which it exists before ignition, in which case it is not recompressed in the working cylinder before ignition, but is ignited either at constant pressure as it enters or at constant volume after the whole charge has been supplied. Two-cycle engines coming within the latter of the above cases are classified as two-cycle pump-compression engines. The combustible mixture is ordinarily supplied to the working cylinder by a pump, and in the first of the above cases, while the charge may be compressed to a considerable degree by the supply-pump, such charge enters the working cylinder only against the pressure of the atmosphere and after having entered must exist therein at or substantially at atmospheric pressure, and the initial compression of the charge upon which the efficiency of an internal-combustion engine so largely depends is produced wholly by recompression of the charge in the working cylinder while in the second case such initial pressure is produced wholly by the supply-pump which compresses the charge directly to the maximum pressure at which it exists before ignition.
SEE OR SEARCH THIS CLASS, SUBCLASS:
61, for double-acting two-cycle engines having a separate and distinct supply pump.
62, for double-acting two-cycle engines in which the engine and supply pump elements are contained within a single cylinder structure.
