Exhaust valve, exhaust valve assembly and exhaust valve system for two-stroke internal combustion engines, two-stroke internal combustion engine having same and method for cleaning an exhaust valve

Patent metadata

Field	Value
Publication number	US-11560864-B2
Application number	US-202217848198-A
Country	US
Kind code	B2
Filing date	Jun 23, 2022
Priority date	Jun 28, 2019
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

A reciprocating exhaust valve for a two-stroke internal combustion engine has a shaft for connection to a valve actuator, the shaft defining a reciprocation axis of the valve, the reciprocation axis defining a longitudinal direction of the valve; and a blade having: a first end having an arcuate edge, a second end connected to the shaft, two side portions, and a central portion. The blade has a first end portion adjacent the first end that includes a part of the central portion and of each of the two side portions. A width of the central portion is greater than a width of each of the side portions. In the first end portion, a thickness of the part of each of the two side portions is greater than a thickness of the part of the central portion.

First claim

What is claimed is:

1. A reciprocating exhaust valve for a two-stroke internal combustion engine comprising:
a shaft for connection to a valve actuator, the shaft defining a reciprocation axis of the valve, the reciprocation axis defining a longitudinal direction of the valve; and
a blade having a first end and a second end opposite the first end,
the shaft being connected to the second end of the blade,
the first end having an arcuate edge,
the blade having two side portions and a central portion,
the central portion being disposed between the two side portions in a lateral direction of the valve, the lateral direction being perpendicular to the longitudinal direction,
the blade having a first end portion adjacent the first end, the first end portion including a part of the central portion and a part of each of the two side portions,
a width of the central portion being greater than a width of each of the side portions, the width of the central portion and the width of each of the side portions being measured in the lateral direction, and
a thickness of the part of each of the two side portions in the first end portion being greater than a thickness of the part of the central portion in the first end portion, the thickness of each of the side portions and the thickness of the central portion being measured in a direction perpendicular to the longitudinal and lateral directions.

2. The reciprocating exhaust valve of claim 1 , wherein the width of the central portion is greater than a sum of the widths of the two side portions.

3. The reciprocating exhaust valve of claim 1 , wherein the width of the central portion is greater than half of a width of the blade, the width of the blade being measured in the lateral direction.

4. The reciprocating exhaust valve of claim 1 , wherein:
the blade has a first face and a second face opposite the first face;
each of the first and second faces extending between the first and second ends;
a majority of the first face is flat; and
the blade having a reinforcing structure provided on the second face.

5. The reciprocating exhaust valve of claim 4 , wherein the reinforcing structure is a plurality of ribs.

6. The reciprocating exhaust valve of claim 1 , wherein a cross-section of each of the two side portions is generally semi-circular, the cross-section being taken through a plane extending in the lateral direction and being normal to the reciprocation axis.

7. The reciprocating exhaust valve of claim 1 , wherein:
the blade has a first face and a second face opposite the first face;
each of the first and second faces extending between the first and second ends;
a majority of the first face is flat;
the two side portions are a first side portion and a second side portion;
a first channel is defined along the second face adjacent to the first side portion;
the first side portion and the central portion define at least in part the first channel;
the first channel is disposed completely on a same side of the reciprocation axis as the first side portion;
a second channel is defined along the second face adjacent to the second side portion;
the second side portion and the central portion define at least in part the second channel;
the second channel is disposed completely on a same side of the reciprocation axis as the second side portion;
the first and second channels extend in the longitudinal direction.

8. The reciprocating exhaust valve of claim 1 , wherein:
the blade has a mid-portion adjacent the first end portion and disposed longitudinally between the first end portion and the second end of the blade;
the mid-portion includes another part of the central portion and another part of each of the two side portions;
a thickness of the other part of the central portion in the mid-portion is greater than the thickness of the part of the central portion in the first end portion.

9. The reciprocating exhaust valve of claim 1 , wherein the shaft defines a stopper.

10. The reciprocating exhaust valve of claim 9 , wherein:
the shaft includes:
a first shaft portion for connection to the valve actuator; and
a second shaft portion connected to the second end of the blade;

the first shaft portion has a first diameter;
at least part of the second shaft portion has a second diameter defining the stopper; and
the second diameter is greater than the first diameter.

11. The reciprocating exhaust valve of claim 1 , wherein the blade is a stainless-steel blade.

12. The reciprocating exhaust valve of claim 1 , wherein the blade and the shaft are integral.

13. A two-stroke internal combustion engine comprising:
an engine block defining:
a cylinder;
an exhaust passage communicating with the cylinder; and
an exhaust valve passage communicating with the exhaust passage;

a piston disposed in the cylinder;
the reciprocating exhaust valve of claim 1 disposed at least in part in the exhaust valve passage; and
an exhaust valve actuator operatively connected to the exhaust valve for moving the blade of the exhaust valve in the exhaust passage.

14. A reciprocating exhaust valve for a two-stroke internal combustion engine comprising:
a shaft for connection to a valve actuator, the shaft defining a reciprocation axis of the valve, the reciprocation axis defining a longitudinal direction of the valve; and
a blade having a first end and a second end opposite the first end,
the first end having an arcuate edge,
the blade having two side portions and a central portion,
the central portion being disposed between the two side portions in a lateral direction of the valve, the lateral direction being perpendicular to the longitudinal direction,
the central portion having two central sub-portions adjacent the second end,
the shaft being connected to the second end laterally between the two central sub-portions,
the central portion having a central mid-portion adjacent the two central sub-portion and disposed longitudinally between the two central sub-portions and the first end of the blade,
a thickness of each of the two central sub-portions being less than a thickness of the central mid-portion, the thickness of each of the two central sub-portions and the thickness of the central mid-portion being measured in a direction perpendicular to the longitudinal and lateral directions.

15. The reciprocating exhaust valve of claim 14 , wherein:
the second end has two arcuate edges; and
the shaft being connected to the second end laterally between the two arcuate edges.

16. The reciprocating exhaust valve of claim 14 , wherein the blade further comprises:
a first flange connected to and extending perpendicularly to one of the two central sub-portions; and
a second flange connected to and extending perpendicularly to another one of the two central sub-portions,
the first and second flanges being adjacent to the second end.

17. The reciprocating exhaust valve of claim 14 , wherein:
the blade has a first face and a second face opposite the first face;
each of the first and second faces extending between the first and second ends;
a majority of the first face is flat; and
the blade having a reinforcing structure provided on the second face.

18. The reciprocating exhaust valve of claim 17 , wherein the reinforcing structure is a plurality of ribs.

19. The reciprocating exhaust valve of claim 14 , wherein:
the blade has a first face and a second face opposite the first face;
each of the first and second faces extending between the first and second ends;
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Assignees

• Brp Us Inc

Inventors

• Johnson Justin
• Zamora Joseph
• Raetzman Roger

Classifications

• F02F3/00

  Pistons · CPC title

• F02F7/0043

  Arrangements of mechanical drive elements · CPC title

• F02F1/4264 Primary

  of exhaust channels · CPC title

• F01L2201/00

  Electronic control systems; Apparatus or methods therefor · CPC title

• F01L1/38 Primary

  for engines with other than four-stroke cycle, e.g. with two-stroke cycle (F01L1/26, F01L1/28 take precedence) · CPC title