Abstract: A reduced volume scavenging system for a two cycle engine embodying a duplex cylinder having an upper cylinder bore and a reduced-diameter lower cylinder bore. The lower bore communicates with a crankcase that houses a crankshaft, connecting rod(s) and engine lubricating oil. A fixed sleeve lines the upper cylinder bore and extends up into the cylinder head. A piston disposed for reciprocating motion within the fixed sleeve has an attached cylindrical, reciprocating sleeve that extends down into the lower cylinder bore and moves with the piston. The reciprocating sleeve has compression rings that seal the lower bore and the crankcase against blowyby gases that might contaminate the oil. The fixed sleeve has an intake opening in registry with an inlet port in the upper cylinder bore for admission of fresh air-fuel mixture.

Abstract: A stepped-piston, internal-combustion engine includes at least one cylinder, each cylinder having a working part of lesser diameter defined by a cylindrical wall and a pumping part of greater diameter, a piston slidable in each cylinder, a receiver which is partly delimited by the cylindrical wall of the working part of each cylinder and which extends at least partly around each working part, working inlet ports in the cylindrical wall and extending between the working part of the cylinder and the receiver and valve means to control the entry of charge into the pumping part of each cylinder and the transfer of charge from said pumping part to the receiver, and wherein the admission of charge into the working part of each cylinder from the receiver is controlled by the uncovering of the working inlet ports by the working part of the piston.

Abstract: An internal combustion engine is provided with a top hat piston disposed in a cylinder having first and second portions of different diameters. The piston, with first and second portions of different diameters, is disposed within the cylinder and defines a compression chamber between a cylinder step and a piston step created by the different diameters. The compression chamber is connected in fluid communication with a fuel supply, such as a carburetor or fuel injector, which provides a fuel/air mixture into the compression chamber during the downstroke of the piston. When the piston is moving upward, it compresses the fuel/air mixture within the compression chamber until a second end of a transfer passage is moved into fluid communication with a transfer port formed in the wall of the first portion of the cylinder. This occurs after the exhaust port is closed by the piston and therefore significantly diminishes the chance for unburned fuel to pass directly out the exhaust port from the combustion chamber.

Abstract: An improved two cycle internal combustion engine, preferably of a stepped piston type, having a unique arcuately shaped transfer deflector valve, which varies by its controlled sliding movement within an inlet passage, the size of exposed opening of an elongated inlet port in the cylinder. The inlet port extends circumferentially part way around the cylinder. The leading end of the valve is preferably angled, in cooperation with the preferably almost tangent orientation of the inlet passage, to induce arcuate movement into each fresh full charge entering the combustion chamber for enhanced fuel charge mixing. In the preferred embodiment, two such valves are symmetrically positioned around the cylinder and arcuately move in unison between closed and open positions over corresponding opposing inlet ports.

Abstract: An improved two-stroke internal combustion engine utilizing a vacuum chamber to create vacuum, which sucks the exhaust out from the combustion chamber, and forces the charge into it.

Abstract: A variable-compression internal-combustion engine has a two-stage cylinder with a relatively large diameter at a first-stage, supercharge end, which is also a power-takeoff end, than at a second-stage, combustion end of the cylinder. Intake air is drawn into the first-stage, supercharge end of the cylinder by a matching larger-diameter, first-stage, supercharge end of a two-stage piston during a compression stroke of a two-stroke cycle of the two-stage piston. During a power stroke, intake air is directed into and contained under pressure in an air-transfer passage that is positioned circumferentially and externally around an outside periphery of a bottom end of the first-stage cylinder.

Abstract: A stepped piston engine comprises first (10), second (11) and third (12) stepped cylinders, each cylinders (10,11,12) having a larger diameter pumping part (10p,11p,12p), and a smaller diameter working part (10w,11w,12w), and a piston (13,14,15) slidable in the cylinder, each piston (13,14,15) being coupled to an output shaft (16) of the engine, first transfer passage means (20) to transfer the precompressed charge from the larger diameter pumping part (10p) of the first cylinder (10) to the smaller diameter working part (11w) of the second cylinder (11), second transfer passage means (21), to transfer precompressed charge from the larger diameter pumping part (11p) of the second cylinder (11) to the smaller diameter working part (124) of the third cylinder (12), and third transfer passage means (22) to transfer precompressed charge from the larger diameter pumping part (12p) of the third cylinder (12) to the smaller diameter working part (10w) of the first cylinder (10).

Abstract: An internal combustion engine has a pair of first and second cylinders (12,14) communicating with a combustion chamber (20) the first cylinder having a larger swept volume than the second cylinder. First and second pistons (16,18) are provided in the cylinders. An inlet port is provided in the first cylinder for delivering a charge of unthrottled fuel while a fuel injector (36) is controlled by a control means (37) to deliver a charge of fuel into the second cylinder (14) as soon as possible after commencement of an induction stroke of the second piston. Movement of the fuel/air mixture from the second cylinder (14) into the combustion chamber (20) is prevented until the second piston (18) is at or near its inner dead center position. The second piston (18) may be formed as a protrusion on the crown of the first piston (16) with the second cylinder (14) being an extension of the first cylinder (12).

Abstract: An internal combustion engine has a pair of stepped cylinders (14,15) in which stepped pistons (P1,P2) are received, each cylinder (14,15) and piston (P1,P2) having a pumping part of larger diameter and a working part of smaller diameter transfer paths from each of the pumping parts of each cylinder to the working part of the other comprising first passage parts (27,27') extending from the pumping parts (15a,14a) to second passage parts (28,28') and third passage parts comprising at least two branches (29,29') connecting the second passage parts (28,28') and the working parts (16a,16b) of the cylinder, the first (27,27') and third (29,29') passage parts each crossing an interface (1) between the crankcase 12 and cylinder block (11) via aligned parts, and the second passage parts (28,28') being wholly contained in the crankcase (12).

Abstract: A lubrication system with oil recovery for a two-stroke engine piston with pump-sump for scavenging, said system consisting of a lubicating oil pressure circulation system having inlet and outlet holes for the oil, said holes passing through the wall of the cylinder, and of shaped scraper rings, each ring being housed within a circular housing or seat obtained on the outside skirt of the piston, said circular housings being provided on the skirt of the piston at a height which does not allow any overlapping of said scraper rings on the transfer ports of the two-stroke engine.

Abstract: A stratified-charge two-stroke internal combustion engine of the kind in which a rich mixture of fuel and air reaches each cylinder from an auxiliary transfer passage, and further air from a main transfer passage. The fuel-supply device for each cylinder is located in the auxiliary transfer passage well upstream of its entry into the cylinder so that substantial mixing of fuel and air takes place before entry. The rate of fuel supply is typically simply related to conditions in the auxiliary passage, and may be governed by a carburetor-type device located there or by a pressure-sensitive device located there and controlling a pump delivering through an injector. Multi-cylinder designs are described with a single fuel-supply device located in an auxiliary passage common to all the cylinders.

Abstract: An engine comprising; a substantially cylindrical housing; a rotor rotatably mounted in said housing on an axis parallel with the longitudinal central axis of the housing to execute an orbital motion within the housing, a plurality of tubular elements each slidably mounted over fixed piston elements projecting substantially inwardly from the housing; said tubular elements being closed at their inner ends and having their inner ends in slidable driving engagement with said rotor for causing reciprocation of the tubular elements over the piston elements upon rotation of the rotor; and the volume of the space defined by the interior of the tubular element and the piston element varying with the rotation of the rotor.

Abstract: A two-stroke internal combustion engine having a stepped piston in which the cylinder casting has a bore of greater diameter to form a pumping part, a bore of lesser diameter to form a working part, exhaust port means in the working part and opposed transfer port means on opposite sides of the working part disposed symmetrically about a plane passing through the longitudinal axis of the cylinder and center of the exhaust port means, the transfer port means being of a form to be produced in the casting process by non-separate cores introduced linearly towards the plane.

Abstract: A mixture-compressing internal combustion engine with a combustion space arranged either in the piston or in the cylinder head and with an ignition source located in the cylinder head; the main volume of the combustion space is thereby delimited by circular arcs, as viewed in plan view, of which the circular arc located closest to the ignition source is arranged at least approximately concentrically about the ignition source; a part of the piston which is matched within this area of the cylinder head adjoins the ignition source so closely that at first a smaller portion of the charge is ignited in the gap which is formed between the cylinder head and this piston part shortly prior to the end of the compression stroke while the main portion of the charge is combusted, at the earliest, beginning with the upper dead-center position of the piston.

Abstract: An internal combustion engine having a power generating assembly consisting of a piston with a top step, in a similarly-shaped cylinder. This defines a reduced top compression chamber into which fuel is injected and wherein combustion takes place due to the heat of air compressed therein. Water is injected through the top wall of the normal-sized lower cylinder portion, and as the top step of the downwardly moving piston clears this wall, the water is converted into steam. An exhaust duct is connected to the intermediate portion of the cylinder and an air admission duct is connected to the lower portion of the cylinder. When the downwardly-moving piston passes the exhaust port and the air admission port, air intake and scavenging take place. The top step of the piston thus acts as a water admission valve for admitting water to be vaporized into steam into the combustion space.

Abstract: A stepped piston two cycle engine, of the type including at least one set of two cylinders each such cylinder having a working part of smaller diameter and a pumping part of larger diameter, at least the air for each charge required by the working part of each cylinder of the set being pumped along transfer passage means from the pumping part of the other cylinder of the set, has the working part of each cylinder provided with exhaust port means, main inlet ports, and auxiliary inlet port means. The main inlet ports are arranged symetrically about and spaced from a plane which contains a longitudinal axis of the cylinder and which passes through the center of the exhaust port means, and the auxiliary inlet port means is provided in the cylinder wall opposite to the exhaust port means.

Abstract: In a two-stroke cycle internal combustion engine a noncompression type pump formed by placing a plate-like secondary piston within a primary piston, between the top and the wrist pin. The reciprocating movements of primary and secondary piston in conjunction with the intake port and transfer port, provide a pump with a longer intake time and less power need, relative to prior art.