Valve seat insert for internal combustion engine profiled to resist valve recession

Patent metadata

Field	Value
Publication number	US-10731523-B2
Application number	US-201816188547-A
Country	US
Kind code	B2
Filing date	Nov 13, 2018
Priority date	Nov 13, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

An internal combustion engine includes a valve seat insert within an engine housing, and a gas exchange valve. The valve seat insert has a compound valve seat with a valve recession-resistive profile formed by a leading radius contacted by the valve seat at an early wear state of the valve head and valve seat insert, a trailing radius contacted by the valve head at a later wear state of the valve head and valve seat insert, and an outer seat face. The compound valve seat is shaped and proportioned to cushion contact by a gas exchange valve and retard valve recession.

First claim

What is claimed is:

1. An internal combustion engine comprising:
an engine housing including a cylinder block having a cylinder formed therein, and an engine head coupled to the cylinder block and having a gas exchange conduit formed therein;
a valve seat insert positioned at least partially within the engine head and having a compound valve seat extending circumferentially around a valve seat center axis;
a gas exchange valve including a valve head having an outer valve face and an inner valve face, and the gas exchange valve being movable between a closed valve position where the inner valve face contacts the compound valve seat and the cylinder is blocked from fluid communication with the gas exchange conduit, and an open valve position;
the compound valve seat having a valve recession-resistive profile formed by a leading radius contacted by the valve head at an early wear state of the valve head and valve seat insert, a trailing radius contacted by the valve head at a later wear state of the valve head and valve seat insert, and an outer seat face;
the inner valve face defining a valve angle relative to a plane oriented normal to the valve seat center axis, and the outer seat face extending from the leading radius to the trailing radius and defining a seat angle relative to the plane; and
the gas exchange valve is at the closed valve position, such that the inner valve face is in contact with the leading radius and the inner valve face overhangs the outer seat face; and
the seat angle being larger than the valve angle, such that the leading radius forms a contact band with the inner valve face and a starting face clearance extends radially inward and axially inward from the contact band.

2. The internal combustion engine of claim 1 wherein the seat angle and the valve angle define an interference angle that is less than 1°.

3. The internal combustion engine of claim 2 wherein the interference angle is about 0.35°.

4. The internal combustion engine of claim 3 wherein the seat angle is about 19.6°, and the valve angle is about 19.3°.

5. The internal combustion engine of claim 2 wherein the outer seat face extends linearly between the leading radius and the trailing radius, and each of the leading radius and the trailing radius is blended with the outer seat face.

6. The internal combustion engine of claim 5 wherein the valve seat insert further includes:
a chamfer located adjacent to the trailing radius, and the trailing radius is blended with the chamfer; and
an end face located adjacent to the leading radius, and the leading radius is blended with the end face.

7. The internal combustion engine of claim 5 wherein a size of the leading radius is larger than a size of the trailing radius, and a size of the outer seat face is greater than a size of the leading radius and the size of the trailing radius.

8. The internal combustion engine of claim 7 wherein the size of the outer seat face is greater than a size of the chamfer and greater than a size of the end face.

9. The internal combustion engine of claim 8 wherein the size of the outer seat face includes a full face width greater than 3 millimeters.

10. A valve seat insert for a gas exchange valve in an internal combustion engine comprising:
an insert body positionable within an engine head and including an outer surface, and an inner surface forming an opening within the insert body to fluidly connect a cylinder in the internal combustion engine to a gas exchange conduit in the engine head;
a compound valve seat formed in the insert body and in communication with the opening, and the compound valve seat extending circumferentially around a valve seat center axis that extends between a leading axial body end and a trailing axial body end;
the inner surface having a non-uniform inner profile that flares outward between the opening and the trailing axial body end, the outer surface having a non-uniform outer profile that dips inward between the leading axial body end and the trailing axial body end, and the compound valve seat having a valve recession-resistive profile;
the valve recession-resistive profile being formed by a leading radius, an outer seat face, and a trailing radius structured, respectively, for contact with a valve head of a gas exchange valve at a contact band that advances radially inward and axially inward at successive wear stages of the valve seat insert and valve head;
the outer seat face extending from the leading radius to the trailing radius, and the leading axial body end including an end face extending from the leading radius toward the outer surface and oriented diagonally to the valve seat center axis; and
the outer seat face defining a seat angle relative to a plane oriented normal to the valve seat center axis that is between 19° and 20°, and having a full face width between the leading radius and the trailing radius that is between 3 millimeters and 4 millimeters.

11. The valve seat insert of claim 10 wherein the outer seat face extends linearly between the leading radius and the trailing radius, and each of the leading radius and the trailing radius is blended with the outer seat face.

12. The valve seat insert of claim 11 wherein a size of the leading radius is greater than a size of the trailing radius.

13. The valve seat insert of claim 12 wherein the size of the leading radius is about 2 millimeters, and the size of the trailing radius is about 1 millimeter.

14. The valve seat insert of claim 10 wherein the seat angle is about 19.6°, and the full face width of the outer seat face is about 3.6 millimeters.

15. The valve seat insert of claim 10 wherein the insert body further includes:
a chamfer located adjacent to the trailing radius, and the trailing radius is blended with the chamfer; and
an end face located adjacent to the leading radius, and the leading radius is blended with the end face.

16. An engine head assembly comprising:
an engine head having a gas exchange conduit formed therein;
a valve seat insert positioned at least partially within the engine head to fluidly connect the gas exchange conduit to an engine cylinder;
the valve seat insert having an outer surface, a leading axial end, a trailing axial end, and having formed therein a compound valve seat extending circumferentially around a valve seat center axis and having a valve recession-resistive profile formed by a leading radius, an outer seat face, and a trailing radius structured, respectively, for contact with a valve head of a gas exchange valve at a contact band that advances radially inward and axially inward at successive wear stages of the valve seat insert and valve head; and
the outer seat face extending from the leading radius to the trailing radius, and the leading axial body end including an end face extending from the leading radius toward the outer surface and oriented diagonally to the valve seat center axis; and defining a seat angle relative to a plane oriented normal to the valve seat center axis that is between 19° and 20° and having a full face width between the leading radius and the trailing radius that is between 3 millimeters and 4 millimeters.

17. The engine head assembly of claim 16 wherein:
the seat angle is about 19.6°;
the full face width of the outer seat face is about 3.6 millimeters;
a size of the leading radius is about 2 millimeters; and
a size of the trailing radius is about 1 millimeter.

18. The engine head assembly of claim 16 wherein the valve seat insert further includes:
a chamfer located adjacent to the trailing radius

Assignees

• Caterpillar Inc

Inventors

• Qu Rong
• Hattiangadi Ashwin
• Kumar Sanjay
• Yoder Kevin D

Classifications

• F01L3/04 Primary

  Coated valve members or valve-seats · CPC title

• F16K1/42

  Valve seats (for double-seat valves F16K1/44) · CPC title

• F01L3/00

  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

• F01L3/22

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

• F02M21/026

  Lift valves, i.e. stem operated valves · CPC title