Piston bowl with deflecting features
AssigneeSouthwest Research Institute
InventorsRainer J. Rothbauer, Charles E. Roberts, Jr., Thomas W. Ryan, III
Life of this patent
Estimating the term…
Abstract
A piston for a direct injection engine is provided, the piston having a bowl at an upper end, the bowl forming a portion of a combustion chamber. The bowl includes an inner surface and a dome that defines a volume configured to receive a fuel-air mixture, the inner surface of the bowl and the dome each including at least one surface feature as a target for the fuel spray. The surface feature may protrude from the inner surface of the bowl or may be recessed into the inner surface. Such surface features may reduce soot and improve fuel-air mixing.
Claims17
A piston for a direct injection engine, the piston comprising a bowl at an upper end, the bowl forming a portion of a combustion chamber, wherein the bowl has a centerline and an inner surface and a dome that defines a bowl volume configured to receive a fuel-air mixture, the dome having a surface that includes at least one separation feature having a separation edge on said dome surface arranged to deflect sprayed fuel to the inner surface of the bowl, where said separation feature is formed as a step in the surface of the dome, the step disposed around the centerline;
- wherein the dome further includes at least one additional feature, wherein the at least one additional feature projects from said dome surface;
- and
- wherein the additional feature defines a surface disposed at an angle of 45-89° from said centerline of said piston bowl which deflects sprayed fuel upwards towards the inner surface of the bowl.
A piston for a direct injection engine, the piston comprising a bowl at an upper end, the bowl forming a portion of a combustion chamber, wherein the bowl has a centerline and an inner surface and a dome that defines a bowl volume configured to receive a fuel-air mixture, the dome having a surface that includes at least one separation feature on said dome surface arranged to deflect sprayed fuel to the inner surface of the bowl, where said separation feature is formed as a step in the surface of the dome, the step disposed around the centreline;
- and
- wherein the dome further includes at least one additional feature, wherein the at least one additional feature projects from said dome surface and said at least one additional feature defines a portion of a cone and includes a surface having a convex shape;
- and
- wherein the additional feature defines a surface disposed at an angle of 45-89° from said centerline of said piston bowl which deflects sprayed fuel upwards towards the inner surface of the bowl.
A method of operating an internal combustion engine having at least one cylinder and a piston slidably disposed within the at least one cylinder, the method comprising:
- moving the piston toward a top dead center position during a compression stroke;
- spraying a fuel into a piston bowl recessed in said piston, wherein the bowl has a centerline and an inner surface and a dome that defines a bowl volume configured to receive a fuel-air mixture, the dome having a surface that includes at least one separation feature having a separation edge on said dome surface arranged to deflect sprayed fuel to the inner surface of the bowl, where said separation feature is formed as a step in the surface of the dome, the step disposed around the centerline,
- wherein the dome further includes at least one additional feature which projects from said dome surface,
- wherein the additional feature defines a surface disposed at an angle of 45-89° from said centerline of said piston bowl which deflects sprayed fuel upwards towards the inner surface of the bowl;
- and
- directing said sprayed fuel to impact said at least one separation feature and said additional feature;
- redirecting said fuel upon impact with at least one of said at least one separation feature and said at least one additional feature to a location within the piston bowl above at least one of said at least one separation feature and said at least one additional feature to provide mixing of the fuel with air in the cylinder.
Dependencies are inferred from the claim text.