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.
Claims14
1-7. (canceled)
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.
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 defines a maximum axial depth measured from a planar squish surface to a bottom concave arcuate surface defining a bottom extremity of a swirl pocket, and the swirl pocket includes a concave arcuate side surface that is spaced axially away from the planar squish surface, and the bottom concave arcuate surface, the concave arcuate side surface defining an axial height, and a ratio of the maximum axial depth of the contoured combustion bowl to the axial height ranges from 6.9 to 8.4.
A combustion chamber of an engine comprising:
- a bore of the engine with a bore diameter, a longitudinal axis, a radial direction perpendicular to the longitudinal axis;
- and
- a piston configured to reciprocate in the bore of the engine from a top dead center position to a bottom dead position defining a compression height therebetween, the piston including
- an annular body including a crown portion and defining 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 defines a maximum axial depth measured from a planar squish surface to a bottom concave arcuate surface defining a bottom extremity of a swirl pocket, and a ratio of the compression height to the maximum axial depth ranges from 5.0 to 15.0.
Dependencies are inferred from the claim text.