US 7,025,021 B1 · Two-stroke internal combustion engine

Abstract

Crankcase scavenged two-stroke internal combustion engine (1), in which a piston ported air passage is arranged between an air inlet (2) and the upper part of a number of transfer ducts (3, 3′). The air inlet is equipped with a restriction valve (4), controlled by at least one engine parameter, for instance the carburettor throttle control. The air inlet extends via at least one connecting duct (6, 6′) to at least one connecting port (7, 7′) in the engine's cylinder wall (12). The connecting port (7, 7′) is arranged so that it in connection with piston positions at the top dead center is connected with flow paths (9, 9′) embodied in the piston (13), which extend to the upper part of a number of transfer ducts (3, 3′), and the flow paths in the piston are so arranged that the recess (10, 10′; 11, 11′) in the piston that meets the respective transfer duct's port (31, 31′) is so arranged that the air supply is given an essentially equally long or longer period, counted as crank angle or time, in relation to the fuel and air mixture inlet period.

Claims50

Dependent claims

A crankcase scavenged two-stroke internal combustion engine comprising:

a piston reciprocatingly arranged within a cylinder;
a flow path configured to selectively place an air inlet duct in fluid communication with a scavenging duct;
said air inlet duct being equipped with a restriction valve controlled by an engine parameter for controlling an amount of air permitted to pass through said air inlet duct;
said air inlet duct extending to an air inlet port formed in a cylinder wall of said engine and said scavenging duct extending from a scavenging port formed in said cylinder wall of said engine;
said air inlet port being positioned in said cylinder wall so that when said piston is positioned in a top dead center configuration, said air inlet duct is connected in fluid communication with said flow path;
said flow path being configured to extend from said air inlet duct to said scavenging duct when said piston is in said top dead center configuration so that a period of air supply through said air inlet duct to said engine is approximately as long as a period of fuel and air mixture supply to said engine during substantially each cycle of said two-stroke internal combustion engine;
and
an upper edge of said air inlet port is located at least as high in said cylinder's longitudinal axial direction as a lower edge of said scavenging port.

5 more elements

A crankcase scavenged two-stroke internal combustion engine comprising:

a piston reciprocatingly arranged within a cylinder;
a flow path configured to selectively place an air inlet port in fluid communication with a scavenging port, said flow path being at least partially formed in said piston and said air inlet port and said scavenging port being established at said cylinder;
and
an upper edge of said air inlet port being located at least as high in said cylinder's longitudinal axial direction as a lower edge of said scavenging port thereby establishing a longitudinally overlapping relationship in said cylinder's longitudinal axial direction between said air inlet port and said scavenging port.

1 more element

A crankcase scavenged two-stroke internal combustion engine comprising:

a piston reciprocatingly arranged within a cylinder;
a flow path configured to selectively place an air inlet duct in fluid communication with a scavenging duct;
said air inlet duct being equipped with a restriction valve controlled by an engine parameter for controlling an amount of air permitted to pass through said air inlet duct;
said air inlet duct extending to an air inlet port formed in a cylinder wall of said engine and said scavenging duct extending from a scavenging port formed in said cylinder wall of said engine;
said air inlet port being positioned in said cylinder wall so that when said piston is positioned in a top dead center configuration, said air inlet duct is thereby connected in fluid communication with said flow path;
said flow path being configured to extend from said air inlet duct to said scavenging duct when said piston is in said top dead center configuration so that a period of air supply through said air inlet duct to said engine is approximately as long as a period of fuel and air mixture supply to said engine during substantially each cycle of said two-stroke internal combustion engine;
and
an upper edge of said air inlet port is located at least as high in said cylinder's longitudinal axial direction as a lower edge of said scavenging port.

5 more elements

Dependencies are inferred from the claim text.

Two-stroke internal combustion engine

Life of this patent

Two-stroke internal combustion engine

Life of this patent

Abstract

Claims50