Piston of internal combustion engine and method of producing same
AssigneeUnisia Jecs Corporation
InventorMasato Sasaki
Life of this patent
Estimating the term…
Abstract
A piston of an internal combustion engine comprises a crown portion constructed of an aluminum alloy. The crown portion has a bowl in a top surface thereof. The bowl serves as a combustion chamber. Boss portions are projected downward from the crown portion. The boss portions have aligned piston pin holes respectively which have a common axis. A generally annular reinforced zone is provided on the top surface of the crown and extends around a peripheral edge of the bowl. The mechanical strength of the reinforced zone gradually lowers as the distance from the common axis increases.
Claims16
A piston of an internal combustion engine, comprising:
- a crown constructed of an aluminum alloy and having a bowl at a top surface thereof, said bowl serving as a combustion chamber;
- boss portions projected downward from said crown, said boss portions having aligned piston pin holes respectively, said aligned piston pin holes having a common first axis;
- and
- a generally annular reinforced zone provided on the top surface of said crown and extending around a peripheral edge of said bowl,
- wherein the mechanical strength of said reinforced zone gradually lowers as the distance from said first axis of said piston pin holes increases and
- wherein said generally annular reinforced zone is provided by fusing a fusible ring put on the crown top surface and a part of a base material of the piston, said fusible ring containing reinforcing materials.
A method of producing a piston of an internal combustion engine, said piston being constructed of an aluminum alloy and having piston pin holes at downward projected portions thereof and a bowl at a crown top surface thereof,
- said method comprising the steps of:
- (a) preparing a blank piston that has no bowl at the crown top surface;
- (b) placing a fusible ring on the crown top surface, said fusible ring containing reinforcing materials;
- (c) fusing said fusible ring and its neighbor of a base material of said blank piston thereby to produce an alloy layer on the crown top surface, the fusing being so made that the amount of the reinforcing materials contained in said alloy layer gradually lowers as the distance from a first axis increases, said first axis being a common axis of said piston pin holes;
- and
- (d) machining a bowl at the crown top surface in the area of said alloy layer.
A internal combustion engine piston, comprising:
- an aluminum alloy crown having a bowl in a top surface thereof;
- boss portions projected downward from said crown, said boss portions having aligned piston pin holes respectively, said aligned piston pin holes having a common first axis;
- and
- a structural strength modifying material which has been diffused into the aluminum alloy via localized fusing of both the material and the aluminum alloy to produce a generally annular reinforced zone on the top surface of said crown which extends around a peripheral edge of said bowl and which has a structural strength that gradually lowers as the distance from said first axis of said piston pin holes increases.
Dependencies are inferred from the claim text.