Piston
First Claim
1. A piston, comprising:
- a piston body and piston crown formed of a ferrous material;
said piston crown including a crown wall presenting an upper surface for being exposed to combustion gases and an undercrown surface for being exposed to cooling oil during operation, said crown wall having a crown wall thickness extending from said upper surface to said undercrown surface, said crown wall thickness being less than 4 mm;
said piston crown including a least one valve pocket formed in said crown wall;
said piston crown including a ring belt extending from said upper surface, said ring belt including a plurality of ring grooves, wherein an axial clearance between said valve pocket and an uppermost one of said ring grooves is less than 1.5 mm;
said piston body including a pair of pin bosses extending from said piston crown, each of said pin bosses including an inner face forming a pin bore surrounding a pin bore axis;
each of said pin bosses including an upper portion between said pin bore and said undercrown surface, said upper portion being spaced from said undercrown surface by a hollowed region, said hollowed regions extending completely through said pin bosses to provide flow passages for cooling oil; and
wherein said piston does not include a closed oil cooling gallery along said undercrown surface.
19 Assignments
0 Petitions
Accused Products
Abstract
A ferrous piston for gasoline powered engines having dimensions which achieve reduced mass and improved performance is provided. The piston crown has a thickness of less than 4 mm and includes valve pockets with an axial clearance between the valve pockets and an uppermost ring groove of less than 1.5 mm. The pin bosses have an axial thickness of less than 3.7% of a bore diameter, which is the largest outer diameter of the piston, measured between a pin bore and the crown at 1 mm from an inner face forming the pin bore. Each pin boss has a radial thickness of less than 3% of the bore diameter measured between the pin bore and a lower end of the pin boss. An undercrown surface presents a projected area of less than 45% of a total piston bore area, wherein the total piston bore area is πBD2/4, BD being the bore diameter.
14 Citations
19 Claims
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1. A piston, comprising:
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a piston body and piston crown formed of a ferrous material; said piston crown including a crown wall presenting an upper surface for being exposed to combustion gases and an undercrown surface for being exposed to cooling oil during operation, said crown wall having a crown wall thickness extending from said upper surface to said undercrown surface, said crown wall thickness being less than 4 mm; said piston crown including a least one valve pocket formed in said crown wall; said piston crown including a ring belt extending from said upper surface, said ring belt including a plurality of ring grooves, wherein an axial clearance between said valve pocket and an uppermost one of said ring grooves is less than 1.5 mm; said piston body including a pair of pin bosses extending from said piston crown, each of said pin bosses including an inner face forming a pin bore surrounding a pin bore axis; each of said pin bosses including an upper portion between said pin bore and said undercrown surface, said upper portion being spaced from said undercrown surface by a hollowed region, said hollowed regions extending completely through said pin bosses to provide flow passages for cooling oil; and wherein said piston does not include a closed oil cooling gallery along said undercrown surface. - View Dependent Claims (2, 3, 4)
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5. A piston, comprising:
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a piston body and piston crown formed of a ferrous material; said piston crown including a crown wall presenting an undercrown surface for being exposed to cooling oil during operation; said piston body presenting a bore diameter being the largest outer diameter of said piston body; said piston body including a pair of pin bosses extending from said piston crown, each of said pin bosses including an inner face forming a pin bore surrounding a pin bore axis; each of said pin bosses having an axial thickness of less than 3.7% of said bore diameter measured between said pin bore and said piston crown at 1 mm from said inner face forming said pin bore; each of said pin bosses having a radial thickness of less than 3% of said bore diameter measured between said pin bore and a lower end of said pin boss; each of said pin bosses including an upper portion between said pin bore and said undercrown surface, said upper portion being spaced from said undercrown surface by a hollowed region, said hollowed regions extending completely through said pin bosses to provide flow passages for cooling oil; and wherein said piston does not include a closed oil cooling gallery along said undercrown surface. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification