Piston assembly with opposing injection regions for an opposed-piston engine

Patent metadata

Field	Value
Publication number	US-2023392564-A1
Application number	US-202318451007-A
Country	US
Kind code	A1
Filing date	Aug 16, 2023
Priority date	Sep 7, 2017
Publication date	Dec 7, 2023
Grant date	—

Abstract

A piston for an opposed-piston, internal combustion engine includes a crown with an end surface having a bowl shaped to form a combustion chamber with an end surface of an opposing piston in the opposed-piston engine. A substantially circumferential top land of the crown meets the end surface at a substantially circular peripheral edge, and a skirt comprising a sidewall extends from a substantially circumferential belt region of the crown. A wristpin bore with a wristpin axis opens through the sidewall. The end surface of the piston includes a pair of injection regions across which fuel is injected into the bowl. The injection regions are disposed in substantially diametrically-opposed quadrants of the end surface which are defined by the wristpin axis and a connecting rod envelope axis substantially orthogonal to the wristpin axis. Each injection region extends along a respective arc concentric with the substantially circular peripheral edge.

First claim

1 . A piston for an opposed-piston engine, comprising:
a crown with an end surface and a top land that meets the end surface at a circular peripheral edge which is centered on a longitudinal axis of the piston; an inner ring belt region in the crown; an outer ring belt region near an outer end of the piston; a bowl in the end surface configured to form a combustion chamber with an adjacent end surface of an opposing piston; a wristpin bore having a wristpin bore axis; the wristpin bore being configured to receive a wristpin that couples the piston to a connecting rod that swings in an envelope of motion that is orthogonal to the wristpin bore axis; the end surface including a pair of injection regions; a respective injection trench situated in each injection region and shaped for guiding a spray of injected fuel into the bowl; wherein the injection regions are situated in respective diametrically-opposed quadrants of the end surface, situated at locations that are offset arcuately between the wristpin bore axis and the envelope of motion; wherein each injection region extends along a respective arc concentric with the center of the circular peripheral edge; and, wherein the respective arc of each injection region subtends an angle of 50-70 degrees, with the vertex of the angle being coincident with a longitudinal axis of the piston.

2 . The piston of claim 1 , the wristpin bore comprising a first opening formed in a first pin boss and a second opening formed in a second pin boss, the first and second openings being coaxially aligned along the wristpin bore axis.

3 . The piston of claim 1 , in which the injection trenches are diametrically opposed.

4 . The piston of claim 1 , the crown further comprising an interior annular cooling gallery defined at least partially by an inner surface of the substantially circumferential top land, and inlet passageways positioned in the interior annular cooling gallery substantially in alignment with the injection regions.

5 . The piston of claim 4 , the wristpin bore comprising a first opening formed in a first pin boss in the sidewall and a second opening formed in a second pin boss in the sidewall, the openings being coaxially aligned along the wristpin bore axis.

6 . The piston of claim 5 , in which the injection trenches are diametrically opposed.

7 . A piston assembly for an opposed-piston engine, comprising:
a crown with an end surface comprising a bowl configured to form a combustion chamber in cooperation with an adjacent end surface of an opposing piston; a substantially circumferential top land of the crown which meets the end surface at a substantially circular peripheral edge; an inner ring belt region in a side surface of the crown; a skirt comprising a sidewall extending away from the crown; a wristpin bore in the sidewall; a wristpin with a wristpin axis received in the wristpin bore; an outer ring belt region in the sidewall; a connecting rod coupled to the wristpin for swinging in an envelope of motion which is substantially orthogonal to the wristpin axis; the end surface including a pair of injection regions; a respective injection trench situated in each injection region and shaped for guiding a spray of injected fuel into the bowl; wherein the injection regions are disposed in respective diametrically-opposed quadrants of the end surface, situated at locations that are offset arcuately between the wristpin bore axis and the envelope of motion; wherein each injection region extends along a respective arc concentric with the center of the circular peripheral edge; and, wherein the respective arc of each injection region subtends an angle of 50-70 degrees, with the vertex of the angle being coincident with a longitudinal axis of the piston.

8 . The piston assembly of claim 7 , the wristpin bore comprising a first opening formed in a first pin boss in the sidewall and a second opening formed in a second pin boss in the sidewall, the openings being coaxially aligned along the wristpin axis.

9 . The piston assembly of claim 7 , each injection trench extending from the substantially circular peripheral edge to the bowl.

10 . The piston assembly of claim 9 , in which the injection trenches are situated in diametrically opposed locations of the end surface.

11 . The piston assembly of claim 7 , the crown further comprising an interior annular cooling gallery defined at least partially by an inner surface of the substantially circumferential top land region and inlet passageways positioned in the interior annular cooling gallery substantially in alignment with the injection trenches.

12 . The piston assembly of claim 11 , the wristpin bore comprising a first opening formed in a first pin boss in the sidewall and a second opening formed in a second pin boss in the sidewall, the openings being coaxially aligned along the wristpin axis.

13 . The piston assembly of claim 12 , each injection trench extending from the substantially circular peripheral edge to the bowl.

14 . The piston assembly of claim 13 , in which the injection trenches are situated in diametrically opposed locations of the end surface.

15 . The piston assembly of claim 7 , in which the injection trenches are positioned along respective arcuate portions of the substantially circular peripheral edge, each arcuate portion spanning about 70° and being substantially centered in one of the diametrically-opposed quadrants.

16 . An opposed-piston engine, comprising:
a cylinder block with a plurality of cylinders disposed in an inline array along a length of the cylinder block; a pair of pistons disposed in opposition in each cylinder; each piston of the pair of pistons comprising an inner ring belt region, an outer ring belt region, and a wristpin bore with a wristpin axis, the wristpin bore for receiving a wristpin coupling the piston to a connecting rod that swings in a connecting rod motion envelope that is substantially orthogonal to the wristpin axis, the piston further comprising a crown with an end surface and a bowl in the end surface configured to form a combustion chamber in cooperation with a bowl of an adjacent end surface of an opposing piston, the end surface including a pair of injection regions across which fuel is injected into the bowl; a respective injection trench situated in each injection region; wherein the injection regions are disposed in respective diametrically-opposed quadrants of the end surface, situated at locations that are offset arcuately between the wristpin bore axis and the envelope of motion; wherein each injection region extends along a respective arc concentric with the center of the circular peripheral edge; and, wherein the respective arc of each injection region subtends an angle of 50-70 degrees, with the vertex of the angle being coincident with a longitudinal axis of the piston.

17 . The engine of claim 16 , the wristpin bore comprising a first opening formed in a first pin boss in the sidewall and a second opening formed in a second pin boss in the sidewall, the openings being coaxially aligned along the wristpin axis.

18 . The engine of claim 16 , the crown further comprising an interior annular cooling gallery defined at least partially by an inner surface of a substantially circumferential top land of the crown, and inlet passageways positioned in the interior annular cooling gallery in alignment with the injection regions.

19 . The engine of claim 16 , the crown further comprising an interior annular cooling gallery defined at le

Assignees

• Achates Power Inc

Inventors

• Mackenzie Ryan G

Classifications

• F02F3/22 Primary

  the fluid being liquid · CPC title

• F02F3/003

  the parts being connected by casting, brazing, welding or clamping · CPC title

• B23P15/10

  pistons · CPC title

• F02F3/0023

  the parts being bolted or screwed together · CPC title

• F02B23/0618

  having in-cylinder means to influence the charge motion · CPC title