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US 6,244,227 B1Granted
Valve assembly using pressurized medium for controlling operating conditions of a two-stroke engine
AssigneeBombardier Inc.
InventorSylvain Matte
Life of this patent
Estimating the term…
Abstract
A valve assembly located adjacent the cylinder structure of a two-stroke engine including a valve piston, a diaphragm and a restricting member. The valve assembly is adapted to vary the height of the exhaust port of this type of engine by moving a restricting member, located in a guide channel communicating with the exhaust port, from a full-flow height position to a restrictive height position (and vice versa). The force necessary to actuate the restricting member is a pressurized medium or a vacuum. A solenoid valve controls the pressurized medium or vacuum delivery to the valve assembly according to the engine speed N and throttle opening for optimum efficiency.
Claims50
A two-stroke engine including:
- a cylinder structure having an inside peripheral wall which defines a cylinder bore with an exhaust port;
- a piston axially reciprocable in said cylinder bore and adapted to open and close said exhaust port;
- a crankcase connected to said cylinder structure including an inside wall which defines an internal chamber;
- said engine, in operation, producing an engine speed N;
- wherein the improvement comprises:
- an exhaust port height adjustment system comprising:
- a valve assembly located adjacent said cylinder structure and including a restricting member mounted in said cylinder structure adjacent to said exhaust port and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium according to said engine speed N and a rate of acceleration of said engine speed.
5 more elements
A two-stroke engine including:
- a cylinder structure having an inside peripheral wall which defines a cylinder bore with an exhaust port;
- a piston axially reciprocable in said cylinder bore and adapted to open and close said exhaust port;
- a crankcase connected to said cylinder structure including an inside wall which defines an internal chamber;
- wherein the improvement comprises:
- an exhaust port height adjustment system comprising:
- a valve assembly located adjacent said cylinder structure and including a restricting member mounted in said cylinder structure adjacent to said exhaust port and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium,
- wherein said valve assembly further comprises a diaphragm connected to said restricting member and said pressurized medium, when directed towards a first side of said diaphragm, applies a force on said diaphragm thereby actuating said restricting member from one of said restrictive height and said full-flow height to the other of said restrictive height and said full-flow height, said first side of said diaphragm also selectively connectable to a vacuum source by a pressure controller and a vacuum pipe to evacuate the pressurized medium from the first side of the diaphragm to increase a speed at which the restricting member returns to said one of said restrictive height and said full-flow height.
5 more elements
A two-stroke engine including:
- a cylinder structure having an inside peripheral wall which defines a cylinder bore with an exhaust port;
- a piston axially reciprocable in said cylinder bore and adapted to open and close said exhaust port;
- a crankcase connected to said cylinder structure including an inside wall which defines an internal chamber;
- said engine, in operation, producing an engine speed N;
- wherein the improvement comprises:
- an exhaust port height adjustment system comprising:
- a valve assembly located adjacent said cylinder structure and including a restricting member mounted in said cylinder structure adjacent to said exhaust port and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium, said pressure source being said internal chamber of said crankcase and said pressurized medium being a lower than atmospheric air pressure created in said internal chamber.
5 more elements
A two-stroke engine including:
- a cylinder structure having an inside peripheral wall which defines a cylinder bore with an exhaust port;
- a piston axially reciprocable in said cylinder bore and adapted to open and close said exhaust port;
- a crankcase connected to said cylinder structure including an inside wall which defines an internal chamber;
- said engine, in operation, producing an engine speed N;
- wherein the improvement comprises:
- an exhaust port height adjustment system comprising:
- a valve assembly located adjacent said cylinder structure and including a restricting member mounted in said cylinder structure adjacent to said exhaust port and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium, said pressure source being a water impeller assembly.
5 more elements
An exhaust port height adjustment system comprising:
- a valve assembly adapted to be located adjacent an engine cylinder and including a restricting member mountable in said cylinder adjacent an exhaust port of the cylinder and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium according to an engine speed N and a rate of acceleration of said engine speed.
An exhaust port height adjustment system comprising:
- a valve assembly adapted to be located adjacent an engine cylinder and including a restricting member mountable in said cylinder adjacent an exhaust port of the cylinder and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium, wherein said valve assembly further comprises a diaphragm connected to said restricting member and said pressurized medium from said pressure source, when directed towards a first side of said diaphragm, applies a force on said diaphragm thereby actuating said restricting member from one of said restrictive height and said full-flow height to the other of said restrictive height and said full-flow height, said first side of said diaphragm also selectively connectable to a vacuum source by a pressure controller and a vacuum pipe to evacuate the pressurized medium from the first side of the diaphragm to increase a speed at which the restricting member returns to said one of said restrictive height and said full-flow height.
An exhaust port height adjustment system comprising:
- a valve assembly adapted to be located adjacent an engine cylinder and including a restricting member mountable in said cylinder adjacent an exhaust port of the cylinder and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium, said pressurized medium being a lower than atmospheric air pressure created in an internal chamber.
An exhaust port height adjustment system comprising:
- a valve assembly adapted to be located adjacent an engine cylinder and including a restricting member mountable in said cylinder adjacent an exhaust port of the cylinder and adjustable between a full-flow height, at which position said restricting member exposes said exhaust port throughout its axial extent, and a restrictive height, at which position said restricting member restricts the axial extent of said exhaust port, said valve assembly being selectively connected to a pressure source, said pressure source producing a pressurized medium;
- wherein in operation, said valve assembly is adapted to actuate and control the position of said restricting member with said pressurized medium, said pressure source being a water impeller assembly.
Dependencies are inferred from the claim text.