Engine and gas exchange valve with under-head fillet contoured for chordal stress mitigation

Patent metadata

Field	Value
Publication number	US-10844758-B2
Application number	US-201916253749-A
Country	US
Kind code	B2
Filing date	Jan 22, 2019
Priority date	Jan 22, 2019
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A gas exchange valve in an internal combustion engine includes a valve head having a sealing face structured to contact a valve seat and defining a face angle. The valve head further includes an under-head fillet transitioning from the inner sealing face to a valve stem, and defining a chordal stress zone within the under-head fillet. The under-head fillet is formed by a material distributed according to a stress-diffusing contour within the chordal stress zone, and is blended with the inner sealing face at a blend angle that is less than the face angle and is in a range of about 18° to about 35°. The valve head contour is associated with resistance to chordal stress-induced fatigue failure.

First claim

What is claimed is:

1. An internal combustion engine comprising:
an engine housing including a cylinder block having a cylinder formed therein, an engine head coupled to the cylinder block and having a gas exchange conduit formed therein, and a valve seat forming an opening to the gas exchange conduit;
a gas exchange valve movable between an open position and a closed position to control fluid communications between the cylinder and the gas exchange conduit;
the gas exchange valve including a valve stem defining a longitudinal axis, and a valve head attached to the valve stem and having an outer combustion face defining a plane oriented normal to the longitudinal axis;
the valve head further including an inner sealing face structured to contact the valve seat at the closed position;
the inner sealing face defining a face angle relative to the plane, and the valve seat defining a seat angle relative to the plane that is greater than the face angle;
the valve head further including an under-head fillet transitioning from the inner sealing face to the valve stem, and defining a chordal stress zone within the under-head fillet;
the under-head fillet defines a radius of curvature that is greater than 16 millimeters and less than 17 millimeters; and
the under-head fillet being formed by a material distributed according to a stress-diffusing contour within the chordal stress zone, and the under-head fillet being blended with the inner sealing face at a blend angle relative to the plane that is less than the face angle and is in a range of about 21° to about 31°.

2. The internal combustion engine of claim 1 further comprising a valve seat insert positioned at least partially within the engine head and including the valve seat, and wherein the face angle is less than 45° and the sealing face and the valve seat define an interference angle of about 1° or less.

3. The internal combustion engine of claim 1 wherein a midpoint of a running length of the under-head fillet is within the chordal stress zone.

4. The internal combustion engine of claim 3 wherein the under-head fillet defines a radius of curvature that is uniform through at least a majority of the running length of the under-head fillet.

5. The internal combustion engine of claim 4 wherein the radius of curvature is greater than 16.5 millimeters.

6. The internal combustion engine of claim 1 wherein the radius of curvature is 16.5 millimeters plus or minus a tolerance of 0.5 millimeters.

7. The internal combustion engine of claim 1 wherein the blend angle is from about 22° to about 30°.

8. The internal combustion engine of claim 1 wherein the gas exchange conduit includes an exhaust conduit and the gas exchange valve includes an exhaust valve.

9. A gas exchange valve for controlling fluid communications between a combustion cylinder and a gas exchange conduit in an internal combustion engine comprising:
a valve body including a valve stem defining a longitudinal axis, and a valve head attached to the valve stem and having an outer combustion face defining a plane oriented normal to the longitudinal axis;
the valve head further including an inner sealing face structured to contact the valve seat at the closed position, and an outer perimetric edge surface extending axially between the outer combustion face and the inner sealing face;
the inner sealing face defining a face angle relative to the plane;
the valve head further including an under-head fillet transitioning from the inner sealing face to the valve stem, and defining a chordal stress zone within the under-head fillet;
the under-head fillet defines a radius of curvature that is greater than 16 millimeters and less than 17 millimeters; and
the under-head fillet being formed by a material distributed according to a stress-diffusing contour within the chordal stress zone, and the under-head fillet being blended with the inner sealing face at a blend angle relative to the plane that is less than the face angle and is in a range of about 21° to about 31°.

10. The gas exchange valve of claim 9 wherein the outer perimetric edge surface is substantially parallel to the longitudinal axis and transitions with the sealing face, and wherein the valve head further includes an annular corner face transitioning from the outer combustion face to the outer perimetric edge surface.

11. The gas exchange valve of claim 9 wherein the outer combustion face defines a combustion face diameter dimension, and the radius of curvature defined by the under-head fillet is greater than 40% of the combustion face diameter dimension.

12. The gas exchange valve of claim 10 wherein the outer combustion face is uniformly planar.

13. The gas exchange valve of claim 11 wherein a midpoint of a running length of the under-head fillet is within the chordal stress zone, and the radius of curvature defined by the under-head fillet is uniform throughout at least a majority of the running length of the under-head fillet.

14. The gas exchange valve of claim 11 wherein the blend angle is from about 22° to about 30°, the face angle is less than 45°, and the radius of curvature is greater than 16 millimeters.

15. The gas exchange valve of claim 14 wherein the radius of curvature is 16.5 millimeters plus or minus a tolerance of 0.5 millimeters.

16. The gas exchange valve of claim 14 wherein the blend angle is from about 21° to about 23°.

17. The gas exchange valve of claim 14 wherein the blend angle is from about 29° to about 31°.

18. A gas exchange valve comprising:
a valve body including a valve stem defining a longitudinal axis, and a valve head attached to the valve stem and having an outer combustion face defining a plane oriented normal to the longitudinal axis;
the valve head further including an inner sealing face extending circumferentially around the longitudinal axis and oriented at a face angle relative to the plane that is less than 45°;
the valve head further including an under-head fillet transitioning from the inner sealing face to the valve stem, and defining a chordal stress zone within the under-head fillet;
the under-head fillet defines a radius of curvature that is greater than 16 millimeters and less than 17 millimeters; and
the valve head is formed throughout by a material, and the under-head fillet being formed by the material distributed according to a stress-diffusing contour within the chordal stress zone, and the material forming a blend between the chordal stress zone and the inner sealing face, and the blend having a blend angle relative to the plane that is in a range of about 18c′ to about 35°.

19. The gas exchange valve of claim 18 wherein:
the outer combustion face defines a combustion face diameter dimension;
the under-head fillet defines a radius of curvature that is greater than 40% of the combustion face diameter dimension; and
the blend angle is from about 22° to about 30°.

20. The gas exchange valve of claim 19 wherein the radius of curvature is 16.5 millimeters plus or minus a tolerance of 0.5 millimeters, and the blend angle is 30° plus or minus a tolerance of 1°.

Assignees

• Caterpillar Inc

Inventors

• Hattiangadi Ashwin
• Qu Rong

Classifications

• F01L2820/01

  Absolute values · CPC title

• F01L3/22

  Valve-seats not provided for in preceding subgroups of this group; Fixing of valve-seats · CPC title

• F01L3/20 Primary

  Shapes or constructions of valve members, not provided for in preceding subgroups of this group · CPC title

• F01L3/00 Primary

  Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof · CPC title

• F16K1/443

  the seats being in series · CPC title