Low compression natural gas engine piston bowl for improved combustion stability
AssigneeCaterpillar Inc.
InventorsAaron S. Ness, Andrew J. Loetz, John R. Brubaker, Christopher L. Batta
Life of this patent
Estimating the term…
Abstract
A piston may have an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl. In the plane containing the longitudinal axis and the radial direction, the crown portion includes a radially outer squish surface, and a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the squish surface defining a tangent that forms a reentrant angle with the squish surface that ranges from 53.0 degrees to 57.0 degrees.
Claims19
A piston configured to reciprocate in the bore of an engine, the piston comprising:
- an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl;
- wherein in the plane containing the longitudinal axis and the radial direction, the contoured combustion bowl is radially surrounded by an annular cooling gallery that defines a maximum annular radial width, the contoured combustion bowl has a swirl pocket including a cylindrical surface defining a minimum diameter of the swirl pocket radially proximate to the maximum annular radial width of the annular cooling gallery, and a ratio of the minimum diameter to the maximum annular radial width ranges from 6.3 to 7.7;
- and
- wherein the swirl pocket further includes a conical diverging surface extending radially outwardly, and axially upwardly from the cylindrical surface of the swirl pocket, and the annular cooling gallery further includes a conical surface that is radially proximate to the conical diverging surface, and that is parallel to the conical diverging surface.
A piston configured to reciprocate in the bore of an engine, the piston comprising:
- an annular body including a crown portion defining a longitudinal axis and having a squish surface, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl;
- wherein in the plane containing the longitudinal axis and the radial direction, the contoured combustion bowl is radially surrounded by an annular cooling gallery that defines a maximum annular radial width;
- the contoured combustion bowl has a swirl pocket including a cylindrical surface, and a diverging surface extending radially, and axially upwardly in a direction of the squish surface, from the cylindrical surface;
- and
- the cylindrical surface defining a minimum diameter of the swirl pocket radially proximate to the maximum annular radial width of the annular cooling gallery, and a ratio of the minimum diameter to the maximum annular radial width ranges from 6.3 to 7.7.
A piston configured to reciprocate in the bore of an engine, the piston comprising:
- an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, a plane containing the longitudinal axis and the radial direction, and a contoured combustion bowl;
- wherein in the plane containing the longitudinal axis and the radial direction, the contoured combustion bowl is radially surrounded by an annular cooling gallery that defines a maximum annular radial width, the contoured combustion bowl has a swirl pocket including a cylindrical surface defining a minimum diameter of the swirl pocket radially proximate to the maximum annular radial width of the annular cooling gallery;
- and
- wherein the swirl pocket further includes a diverging surface extending radially outward and axially upward of the cylindrical surface, and the annular cooling gallery further includes a cooling gallery inner surface that is radially proximate to the diverging surface, and the cooling gallery inner surface is arranged parallel to the diverging surface, such that a local wall thickness defined between the diverging surface and the cooling gallery inner surface and extending from the swirl pocket to the annular cooling gallery is constant.
Dependencies are inferred from the claim text.