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US 10,294,888 B2Granted
Piston balancing heat dissipation and combustion properties in internal combustion engine
AssigneeCaterpillar Inc.
InventorsShu Zhang, Aaron Harmon, Nikhil Lulla
Life of this patent
Estimating the term…
Abstract
A piston for an internal combustion engine includes a piston crown having a combustion bowl formed therein, a piston rim extending circumferentially around the combustion bowl and a heat-dissipating chamfer between the combustion bowl and the piston rim. The chamfer is structured by way of at least one of size, angle, or material thickness to an oil gallery to balance heat dissipation with combustion properties. Related methodology is disclosed.
Claims20
A method of operating an internal combustion engine comprising:
- moving a piston in a cylinder of the internal combustion engine toward a top dead center position such that a pressure in the cylinder is increased up to or above an autoignition pressure;
- directly injecting a fuel into the cylinder via a fuel injector;
- autoigniting a mixture of the fuel and air when the pressure in the cylinder is at or above the autoignition pressure;
- heating a material forming an end face of the piston by way of combustion of the autoignited mixture, the end face of the piston being defined by a non-reentrant combustion bowl, an annular piston rim having a curved profile, and a heat-dissipating chamfer, such that the annular piston rim extends circumferentially around a longitudinal piston axis and slopes toward the heat-dissipating chamfer, and wherein the heat-dissipating chamfer extends axially and radially between an outer edge of the combustion bowl and the annular piston rim, said heat-dissipating chamfer being oriented at an angle of approximately 40 to 50 degrees relative to the longitudinal piston axis;
- and
- dissipating heat from the material forming the end face of the piston to oil flowing through an oil gallery disposed within the piston, the oil gallery defined by a back side cooling surface of the piston that is positioned opposite to the combustion bowl such that the back side cooling surface extends parallel to in a concave outer section of the combustion bowl.
3 more elements
A piston for an internal combustion engine comprising:
- a piston body structured for reciprocation within a cylinder of the internal combustion engine to increase a pressure in the cylinder to an autoignition pressure for autoigniting a mixture of fuel and air, the piston body including a piston end face, the piston end face defined by a non-reentrant combustion bowl, an annular piston rim having a curved profile, and a chamfer, such that the annular piston rim extends circumferentially around a longitudinal piston axis and slopes toward the chamfer, and wherein the chamfer extends axially and radially between an outer edge of the combustion bowl and the annular piston rim, said chamfer being oriented at an angle of approximately 40 to 50 degrees relative to the longitudinal piston axis;
- the piston body further defined by an oil gallery formed therein, the oil gallery defined by a back side cooling surface of the piston that is positioned opposite to the combustion bowl such that the back side cooling surface extends parallel to a concave outer section of the combustion bowl, such that at least one of a size of the chamfer, an orientation of the chamfer, or a thickness of a material of the piston body between the chamfer and the oil gallery is structured to balance heat dissipation to oil flowing through the oil gallery with combustion properties of the piston.
A piston crown comprising:
- a piston body crown piece structured for coupling with a piston body skirt piece to form a one-piece piston body having an oil gallery formed therein and being reciprocal within a cylinder of an internal combustion engine to increase a pressure in the cylinder to an autoignition pressure for autoigniting a mixture of fuel and air, the piston body crown piece including a piston end face, the piston end face defined by a non-reentrant combustion bowl, an annular piston rim having a curved profile, and a chamfer, such that the annular piston rim extends circumferentially around a longitudinal piston axis and slopes toward the chamfer, and wherein the chamfer extends axially and radially between an outer edge of the combustion bowl and the annular piston rim, said chamfer being oriented at an angle of approximately 40 to 50 degrees relative to the longitudinal piston axis;
- the oil gallery defined by a back side cooling surface of the piston body that is positioned opposite to the combustion bowl such that the back side cooling surface extends parallel to a concave outer section of the combustion bowl, such that at least one of a size of the chamfer, an orientation of the chamfer, or a thickness of a material of the piston body between the chamfer and the oil gallery is structured to balance heat dissipation to oil flowing through the oil gallery with combustion properties of the piston.
Dependencies are inferred from the claim text.