Low compression natural gas engine piston bowl for improved combustion stability
AssigneeCaterpillar Inc.
InventorsSrikanth Ravisankar, Paul Jon Schweiger
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 33.0 degrees to 37.0 degrees.
Claims20
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 crown portion includes a top squish surface, and
- a swirl pocket having a reentrant surface that extends axially downwardly and radially outwardly from the top squish surface defining a tangent that forms a reentrant angle with the top squish surface that ranges from 33.0 degrees to 37.0 degrees.
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 maximum diameter of the swirl pocket radially proximate to the maximum annular radial width of the annular cooling gallery, and a ratio of the maximum diameter of swirl pocket to the maximum annular radial width ranges from 15.86 to 19.19.
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 a minimum axial depth measured from a plateau surface to the planar squish surface, and a ratio of the maximum axial depth of the contoured combustion bowl to the minimum axial depth ranges from 1.87 to 2.26.
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 10.0 to 12.0.
Dependencies are inferred from the claim text.