Self-igniting internal combustion engine having piston recesses having swirl steps

Patent metadata

Field	Value
Publication number	US-9670826-B2
Application number	US-201113812452-A
Country	US
Kind code	B2
Filing date	Jul 13, 2011
Priority date	Jul 28, 2010
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A self-igniting internal combustion engine includes at least one cylinder and a piston, which can be moved back and forth in the cylinder and which bounds a combustion chamber together with the cylinder and which has a piston recess facing the combustion chamber, said piston recess having flow cross-sections that vary in a circumferential direction of the cylinder and of the piston, and comprising an injector arranged centrally above the piston recess for injecting fuel into the piston recess, wherein the injector has a plurality of injection openings. In order to reduce the emissions and in particular the soot emissions of the internal combustion engine, at least some of the injection openings have different opening cross-sections, wherein the injection openings having the different opening cross-sections are directed at areas of the combustion chamber recess having different flow cross-sections.

First claim

The invention claimed is:

1. A self-igniting internal combustion engine, comprising:
at least one cylinder;
a piston movable within the cylinder, said piston together with the cylinder delimiting a combustion chamber, said piston having a piston recess facing toward the combustion chamber, said piston recess having flow cross sections which vary in a circumferential direction of the cylinder and the piston; and
an injector for injection of fuel into the piston recess, said injector being arranged centrally above the piston recess and having multiple injection openings, wherein at least some of the injection openings have different opening cross sections, and are respectively directed toward regions of the combustion recess having different said flow cross sections.

2. The self-igniting internal combustion engine of claim 1 , wherein the at least some of the injection openings are respectively directed towards regions of the piston recess which differ from one another with regard to a distance between an outer circumference of the piston recess and a longitudinal center axis of the cylinder and the piston.

3. The self-igniting internal combustion engine of claim 1 , wherein the at least some of the injection openings are respectively directed towards regions of the piston recess which differ from one another with regard to a depth of the piston recess.

4. The soft-igniting internal combustion engine of claim 1 , wherein the injector has multiple pairs of injection openings, each of said pairs including an injection opening having a greater opening cross section and an injection opening having a smaller opening cross section, and wherein the injection openings having the greater opening cross section alternate with the injection openings having the smaller opening cross section.

5. The self-igniting internal combustion engine of claim 4 , wherein the injection openings having the greater opening cross section are directed toward regions of the piston recess with a grater flow cross section and the injection openings with the smaller opening cross sections are directed toward regions of the piston recess with a smaller flow cross section.

6. The self-igniting internal combustion engine of claim 1 , wherein the piston recess is not rotationally symmetric in relation to a longitudinal center axis of the cylinder and the piston.

7. The self-igniting internal combustion engine of claim 1 , wherein the piston recess has multiple planes of symmetry whose number corresponds to a number of the pairs of injection openings, and wherein each of the flow cross sections of the piston recess has a maximum or a minimum in one of the planes of symmetry and decreases from the maximum or increases from the minimum up to a neighboring one of the planes of symmetry.

8. The self-igniting internal combustion engine of claim 1 , wherein the piston recess has a convexly curved outer circumference, wherein a radius of curvature of said outer circumference is greater in regions of the piston recess having greater said flow cross sections, than a radius of curvature of said outer circumference in regions of the piston recess having smaller said flow cross sections.

9. The self-igniting internal combustion engine of claim 1 , wherein the piston recess has an outer circumference free of discontinuities.

10. The self-igniting internal combustion engine of claim 1 , wherein the piston recess has a key-shaped cross section with an extended bulge portion, and a narrowed neck portion between the bulge portion and a site of entry of the piston recess into a plane front surface of the piston.

11. The self-igniting internal combustion engine of claim 1 , further comprising a substantially pyramid-shaped projection, said projection projecting upwards from a center of the piston recess over a bottom of the piston recess and having rounded corners and a rounded tip.

Assignees

• Gabel Klaus
• Audi Ag

Inventors

• Gabel Klaus

Classifications

• F02B23/0651

  the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space · CPC title

• F02M61/1826

  Discharge orifices having different sizes · CPC title

• F02B23/0672

  Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis (the surrounding wall being exactly vertical F02B23/0696) · CPC title

• F02B15/00 Primary

  Engines characterised by the method of introducing liquid fuel into cylinders and not otherwise provided for · CPC title

• F02B23/0621 Primary

  Squish flow · CPC title