Piston with oxidation catalyst
AssigneeGeneral Motors Corporation
InventorsMark W. Verbrugge, Yar-Ming Wang, Hong-Hsiang Kuo, Hsai-Yin Lee
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Abstract
Pistons reciprocating in cylinders of a hydrocarbon-fueled internal combustion engine tend to trap air and unburned fuel between the top of the piston head and its enclosing cylinder wall. The circumferential side surface (or land) of the piston head above its upper piston ring groove is provided with a thin coating of porous aluminum oxide. Particles of an oxidation catalyst for the engine's fuel are electrolytically deposited in the pores of the oxide coating. During engine operation the oxide-supported catalyst particles promote combustion of the entrained fuel.
Claims12
An aluminum alloy piston for reciprocation in a cylinder bore of a hydrocarbon-fueled internal combustion engine, the piston comprising:
- a piston head with a top surface and a circumferential side surface between the top surface and a piston ring groove spaced from the top surface;
- the circumferential side surface comprising a porous coating of aluminum oxide and particles of an oxidation catalyst for the fuel within the pores of the aluminum oxide coating.
A method of making an aluminum alloy piston for reciprocation in a cylinder bore of a cylinder block of a hydrocarbon-fueled internal combustion engine, the piston comprising a piston head with a top surface and a circumferential side surface between the top surface and a piston ring groove spaced from the top surface;
- the method comprising:
- electrolytically forming a layer of porous aluminum oxide on the circumferential land surface portion;
- and then
- electrolytically depositing particles of an oxidation catalyst in the pores of the aluminum oxide layer.
Dependencies are inferred from the claim text.