Piston thermal management in an opposed-piston engine
First Claim
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1. An internal combustion engine comprising:
- at least one cylinder with longitudinally-separated exhaust and intake ports and a pair of pistons disposed in opposition to one another in a bore of the cylinder, each piston including a piston body with a crown at one end, an end surface on the crown, and a bowl formed in the end surface, in which a combustion chamber has a cavity defined between the end surface bowls when the pistons are near respective top dead center positions in the cylinder;
wherein;
each piston includes at least one ring groove in a piston sidewall near the crown, and a thermal resistor for reducing or blocking heat transfer from the crown to the at least one ring groove, the thermal resistor comprising;
an annular cavity in the piston sidewall along a circumference of the piston body and positioned between the end surface and the at least one ring groove, the annular cavity having a mouth that opens through the piston sidewall; and
a low thermal conductivity material contained in the annular cavity, in which a sleeve is seated on an outer circumferential surface of the crown with an upper flange held against a shoulder of the crown and a lower flange covering the mouth of the annular cavity, the upper flange extending in a radial direction of the piston and the lower flange extending downwardly in an axial direction of the piston.
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Abstract
An opposed-piston engine includes pistons, each piston having an annular cavity in the piston'"'"'s sidewall and positioned between its crown and ring grooves to block transfer of heat from the crown to the piston body.
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Citations
16 Claims
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1. An internal combustion engine comprising:
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at least one cylinder with longitudinally-separated exhaust and intake ports and a pair of pistons disposed in opposition to one another in a bore of the cylinder, each piston including a piston body with a crown at one end, an end surface on the crown, and a bowl formed in the end surface, in which a combustion chamber has a cavity defined between the end surface bowls when the pistons are near respective top dead center positions in the cylinder;
wherein;each piston includes at least one ring groove in a piston sidewall near the crown, and a thermal resistor for reducing or blocking heat transfer from the crown to the at least one ring groove, the thermal resistor comprising; an annular cavity in the piston sidewall along a circumference of the piston body and positioned between the end surface and the at least one ring groove, the annular cavity having a mouth that opens through the piston sidewall; and a low thermal conductivity material contained in the annular cavity, in which a sleeve is seated on an outer circumferential surface of the crown with an upper flange held against a shoulder of the crown and a lower flange covering the mouth of the annular cavity, the upper flange extending in a radial direction of the piston and the lower flange extending downwardly in an axial direction of the piston. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A piston for a two-stroke internal combustion engine, comprising:
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a piston body with a crown and a sidewall; an end surface formed on the crown; the end surface including an elongated bowl that defines a combustion chamber with an opposing piston end surface; at least one ring groove in the piston sidewall near the crown;
a thermal resistor for reducing or blocking heat transfer from the crown to the at least one ring groove, the thermal resistor comprising;an annular cavity in the piston sidewall along a circumference of the piston body and positioned between the end surface and the at least one ring groove, the annular cavity having a mouth that opens through the piston sidewall; a low thermal conductivity material contained in the annular cavity; and a sleeve seated on an outer circumferential surface of the crown, the sleeve comprising an upper flange held against a shoulder of the crown and a lower flange covering the mouth of the annular cavity, the upper flange extending in a radial direction of the piston and the lower flange extending downwardly in an axial direction of the piston. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification