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US 10,801,396 B2Granted
Mixture-lubricated four-stroke engine
AssigneeAndreas Stihl AG & Co. KG
InventorsGordon Groskopf, Manuel Dangelmaier
Life of this patent
Estimating the term…
Abstract
A mixture-lubricated four-stroke engine has a cylinder and a piston. On the piston, at least one piston ring is arranged. Between valve drive chamber and crankcase interior, at least one first channel is arranged. The first opening of the first channel lies in the bottom dead center position of the piston below each piston ring. At the first opening, the first channel defines a first middle flow direction for mixture flowing into the crankcase interior. The first middle flow direction extends inclined towards the combustion chamber and in a viewing direction perpendicular to the cylinder longitudinal plane intersects the longitudinal center axis above the first opening of the first channel.
Claims16
A mixture-lubricated four-stroke engine comprising:
- a cylinder;
- a piston;
- at least one piston ring arranged on said piston;
- said cylinder and said piston conjointly delimiting a combustion chamber;
- a piston pin;
- a crankpin;
- a connecting rod mounted on said piston pin and said crankpin;
- a crankcase defining a crankcase interior;
- a crankshaft arranged in said crankcase interior and defining a crankshaft axis;
- said piston being configured to drive said crankshaft via said connecting rod;
- an inlet valve;
- an outlet valve;
- a valve control for said inlet valve and said outlet valve;
- said crankshaft being configured to drive said valve control for said inlet valve and said outlet valve;
- a mixture preparation unit for preparing a mixture;
- an intake channel for receiving said mixture;
- said inlet valve being connected to said mixture preparation unit via said intake channel;
- a valve drive chamber;
- said crankcase interior being flow-connected to said intake channel via said valve drive chamber;
- at least one first channel being part of the flow-connection and being arranged between said valve drive chamber and said crankcase interior so as to permit said mixture to flow from said intake channel through said valve drive chamber and via said at least one first channel into said crankcase interior in response to an underpressure in said crankcase interior;
- said at least one first channel defining a first opening which opens into said crankcase interior and a second opening which opens into said valve drive chamber;
- said cylinder having a cylinder bore defining a longitudinal center axis;
- said longitudinal center axis and said crankshaft axis conjointly defining a cylinder longitudinal plane;
- said piston having a bottom dead center position;
- said first opening of said at least one first channel lying below each of said at least one piston ring in said bottom dead center position of said piston;
- said at least one first channel, at said first opening, defining a first middle flow direction for mixture flowing into said crankcase interior;
- and,
- said first middle flow direction extending inclined towards said combustion chamber and, in a viewing direction perpendicular to said cylinder longitudinal plane, intersecting said longitudinal center axis above said first opening of the at least one first channel.
25 more elements
A mixture-lubricated four-stroke engine comprising:
- a cylinder;
- a piston;
- at least one piston ring arranged on said piston;
- said cylinder and said piston conjointly delimiting a combustion chamber;
- a piston pin;
- a crankpin;
- a connecting rod mounted on said piston pin and said crankpin;
- a crankcase defining a crankcase interior;
- a crankshaft arranged in said crankcase interior and defining a crankshaft axis;
- said piston being configured to drive said crankshaft via said connecting rod;
- an inlet valve;
- an outlet valve;
- a valve control for said inlet valve and said outlet valve;
- said crankshaft being configured to drive said valve control for said inlet valve and said outlet valve;
- a mixture preparation unit;
- an intake channel;
- said inlet valve being connected to said mixture preparation unit via said intake channel;
- a valve drive chamber;
- said crankcase interior being flow-connected to said intake channel via said valve drive chamber;
- at least one first channel being part of the flow-connection and being arranged between said valve drive chamber and said crankcase interior;
- said at least one first channel defining a first opening which opens into said crankcase interior and a second opening which opens into said valve drive chamber;
- said cylinder having a cylinder bore defining a longitudinal center axis;
- said longitudinal center axis and said crankshaft axis conjointly defining a cylinder longitudinal plane;
- said piston having a bottom dead center position;
- said first opening of said at least one first channel lying below each of said at least one piston ring in said bottom dead center position of said piston;
- said at least one first channel, at said first opening, defining a first middle flow direction for mixture flowing into said crankcase interior;
- said first middle flow direction extending inclined towards said combustion chamber and, in a viewing direction perpendicular to said cylinder longitudinal plane, intersecting said longitudinal center axis above said first opening of the at least one first channel;
- a second channel having a first second channel opening and a further second channel opening;
- said crankcase interior and said valve drive chamber being flow-connected by said second channel;
- wherein said first second channel opening of said second channel opens into said crankcase interior and said further second channel opening opens into said valve drive chamber;
- and,
- wherein:
- said piston has a top dead center position;
- said crankshaft defines a crankshaft longitudinal plane disposed perpendicularly relative to said longitudinal center axis and containing said crankshaft axis;
- said second channel, at a center point of said first second channel opening, defines a second middle flow direction;
- and,
- said second middle flow direction in the viewing direction perpendicular to the crankshaft longitudinal plane is inclined relative to said cylinder longitudinal plane in such a manner that a flow of the mixture flowing through said second channel into said crankcase interior has a directional component in the top dead center position which is directed against a movement direction of said crankpin.
34 more elements
Dependencies are inferred from the claim text.