Steel piston with cooling gallery and method of construction thereof
First Claim
1. A piston for an internal combustion diesel engine, comprising:
- an upper piston part;
a lower piston part, at least said lower piston part being fabricated from a ferrous based material, said lower piston part having a pair of pin bosses formed with associated pin bores aligned along a pin bores axis which extends transversely to a central longitudinal axis along which the piston reciprocates, said lower piston part further including a pair of piston skirt portions that are formed of one piece with said pin bosses of the same material;
said upper and lower piston parts each including an outer annular wall and an inner annular wall spaced radially apart from one another and presenting a channel portion between each of said inner and outer walls, said inner and outer walls of said upper piston part being permanently joined across inner and outer weld joints to said respective inner and outer walls of said lower piston part to define therebetween an annular cooling gallery that has two side walls provided by the joined together inner and outer walls, an annular top wall formed by the upper piston part and a bottom wall formed by the lower piston part, said bottom wall forming a floor of said annular cooling gallery, said floor undulating relative to said central longitudinal axis along a pair of diametrically opposite low portions and a pair of diametrically opposite high portions, each of said high portions extending over separate ones of said pin bosses and each of said diametrically opposite low portions extending continuously between said pair of diametrically opposite high portions;
said joined together upper and lower piston parts including a combustion bowl defined in part by an inner surface of said joined together inner walls, and further including a generally dome-shaped bottom wall of said combustion bowl extending radially inwardly of said inner wall of said lower piston part;
said inner weld joint being exposed to said combustion bowl;
said joined together piston parts including a piston height dimension, PH, measured from a bottom edge of said pin bosses to a top face of said top wall;
said joined together piston parts including a compression height dimension, CH, measured from said pin bore axis to said top face of said top wall;
said joined together piston parts including a piston diameter, PD, measured as the outer diameter of the top wall; and
wherein said PD equals about 103 mm, said CH equals about 40 mm and the ratio of CH/PH equals about ⅔
.
21 Assignments
0 Petitions
Accused Products
Abstract
A piston and method of construction is provided. The piston includes a top part fixed to a bottom part. The top part has an uppermost surface with annular inner and outer upper joining surfaces depending therefrom. The bottom part has a pair of pin bosses with pin bores aligned with one another along a pin bore axis; a pair of upwardly extending annular inner and outer lower joining surfaces and a combustion bowl wall. Inner and outer weld joints fix the inner and outer upper and lower joining surfaces to one another. An annular cooling gallery is formed laterally between the upper and lower joining surfaces. The inner weld joint joining the top part to the bottom part is located within the combustion bowl wall and configured to minimized the compression height of the piston.
43 Citations
18 Claims
-
1. A piston for an internal combustion diesel engine, comprising:
-
an upper piston part; a lower piston part, at least said lower piston part being fabricated from a ferrous based material, said lower piston part having a pair of pin bosses formed with associated pin bores aligned along a pin bores axis which extends transversely to a central longitudinal axis along which the piston reciprocates, said lower piston part further including a pair of piston skirt portions that are formed of one piece with said pin bosses of the same material; said upper and lower piston parts each including an outer annular wall and an inner annular wall spaced radially apart from one another and presenting a channel portion between each of said inner and outer walls, said inner and outer walls of said upper piston part being permanently joined across inner and outer weld joints to said respective inner and outer walls of said lower piston part to define therebetween an annular cooling gallery that has two side walls provided by the joined together inner and outer walls, an annular top wall formed by the upper piston part and a bottom wall formed by the lower piston part, said bottom wall forming a floor of said annular cooling gallery, said floor undulating relative to said central longitudinal axis along a pair of diametrically opposite low portions and a pair of diametrically opposite high portions, each of said high portions extending over separate ones of said pin bosses and each of said diametrically opposite low portions extending continuously between said pair of diametrically opposite high portions; said joined together upper and lower piston parts including a combustion bowl defined in part by an inner surface of said joined together inner walls, and further including a generally dome-shaped bottom wall of said combustion bowl extending radially inwardly of said inner wall of said lower piston part; said inner weld joint being exposed to said combustion bowl; said joined together piston parts including a piston height dimension, PH, measured from a bottom edge of said pin bosses to a top face of said top wall; said joined together piston parts including a compression height dimension, CH, measured from said pin bore axis to said top face of said top wall; said joined together piston parts including a piston diameter, PD, measured as the outer diameter of the top wall; and wherein said PD equals about 103 mm, said CH equals about 40 mm and the ratio of CH/PH equals about ⅔
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
18. A piston for an internal combustion diesel engine, comprising:
-
an upper piston part having radially spaced inner and outer joining surfaces; a lower piston part with radially spaced inner and outer joining surfaces and fabricated of ferrous based material; inner and outer weld joints permanently joining said inner and said outer joining surfaces of said upper and said lower piston parts, respectively, and defining a cooling gallery therebetween and a combustion bowl inward of said cooling gallery and open to a top of the piston, said cooling gallery having a floor; said inner weld joint extending between said cooling gallery and said combustion bowl; said lower piston part including a pair of pin bosses and associated pin bores aligned along a common pin bore axis which extends transversely to a central longitudinal axis along which the piston reciprocates, and a pair of skirt portions formed as one piece with said pin bosses of the same material, said floor of said cooling gallery undulating relative to said central longitudinal axis along a pair of diametrically opposite low portions and a pair of diametrically opposite high portions, each of said diametrically opposite high portions extending over said pin bosses and each said pair of diametrically opposite low portions extending continuously between said pair of diametrically opposite high portions; said piston having a top face with an outer piston diameter, PD, and a compression height, CH, measured as the distance from said pin bore axis to said top face of said piston; and
wherein CH is between 38% to 45% of PD.
-
Specification