Multi-part piston construction for an opposed-piston engine

Abstract

A piston for an internal combustion opposed-piston engine includes a crown part, a skirt part, and an outer part. The crown part includes a first ring belt region for supporting compression rings and an end surface shaped to form a combustion chamber with an end surface of an opposing piston. The skirt part includes a sidewall and a wristpin bore with a first opening and a second opening formed in the sidewall. The outer part includes a second ring belt region for supporting oil control rings. The crown part is joined to an upper end of the sidewall with one or more welding seams. The outer part is joined to a lower end of the sidewall with a welding seam.

1 . A multi-part piston of a two-stroke cycle, internal combustion engine comprising:
 a crown part with a first circumferential ring belt region;   a skirt part with a sidewall including a first end and a second end; and,   an outer part with a second circumferential ring belt region;   wherein the crown part is joined to the first end of the skirt part by one or more first weld seams and the outer part is joined to the second end of the skirt part by a second weld seam.   
     
     
         2 . The piston of  claim 1 , wherein the crown part is made of a first material and the skirt part is made of a second material. 
     
     
         3 . The piston of  claim 2 , wherein the first material comprises a metal or metal alloy with a high strength at high temperatures, and the second material comprises one or more of: 4140 steel, stainless steel, 10xx carbon steel, ductile iron, austempered ductile iron, compacted graphite iron, grey iron, any type of SAE graded steel, titanium, an austenitic nickel-chromium-based superalloy, and a nickel-based steel alloy. 
     
     
         4 . The piston of  claim 1 , wherein the crown part comprises a forged metal part and the skirt part comprises a forged metal part. 
     
     
         5 . The piston of  claim 1 , wherein the crown part comprises a forged metal part and the lower part comprises a forged metal part. 
     
     
         6 . The piston of  claim 1 , wherein the skirt part comprises a forged metal part and the lower part comprises a forged metal part. 
     
     
         7 . A piston of an opposed-piston engine, comprising:
 a crown part comprising an end surface including means for forming a combustion chamber with an end surface of an opposing piston in a cylinder of an opposed-piston engine, and a circumferentially-extending compression ring belt region with one or more ring grooves;   a skirt part comprising a first end, a second end, and a wristpin bore with a wristpin bore axis formed in a sidewall of the skirt part;   an outer part comprising a circumferentially-extending oil ring belt region with one or more ring grooves;   one or more first weld seams joining the crown part with the first end of the skirt part; and   a second weld seam joining the second end of the skirt part with the outer part;   in which the compression ring belt region is coaxially aligned with the oil ring belt region along a longitudinal axis of the piston.   
     
     
         8 . The piston of  claim 7 , wherein the crown part is made of a first material and the skirt part is made of a second material. 
     
     
         9 . The piston of  claim 8 , wherein the first material comprises a metal or metal alloy with a high strength at high temperatures, and the second material comprises one or more of: 4140 steel, stainless steel, 10xx carbon steel, ductile iron, austempered ductile iron, compacted graphite iron, grey iron, any type of SAE graded steel, titanium, an austenitic nickel-chromium-based superalloy, and a nickel-based steel alloy. 
     
     
         10 . The piston of  claim 7 , wherein the crown part comprises a forged metal part and the skirt part comprises a forged metal part. 
     
     
         11 . The piston of  claim 7 , wherein the crown part comprises a forged metal part and the outer part comprises a forged metal part. 
     
     
         12 . The piston of  claim 7 , wherein the skirt part comprises a forged metal part and the outer part comprises a forged metal part. 
     
     
         13 . The piston of  claim 7 , wherein the crown part comprises a forged metal base crown including 4140 steel and, the skirt part comprises a forged metal base skirt including a steel alloy or an aluminum alloy. 
     
     
         14 . The piston of any one of  claims 7 - 13 , wherein the means for forming a combustion chamber includes an axis registered to the longitudinal wristpin bore axis with a predetermined angle between the two axes. 
     
     
         15 . A method for making a piston of an opposed-piston engine, the method comprising:
 providing a crown part comprising a sidewall with a first ring belt region;   providing a skirt part, the skirt part comprising a wristpin bore having a longitudinal wristpin bore axis;   providing an outer part that comprises a second ring belt region;   welding the crown part and skirt part together; and   welding the outer part and the skirt part together.   
     
     
         16 . The method of  claim 15 , further comprising transforming a piece of metal using forging to create the crown part, the skirt part, and/or the outer part of the piston. 
     
     
         17 . The method of  claim 16 , wherein welding the crown part and skirt part together comprises one or more of friction welding, shielded active gas welding, shielded metal arc welding, gas tungsten arc welding, gas metal arc welding, flux-cored arc welding, submerged arc welding, electroslag welding, and electric resistance welding. 
     
     
         18 . The method of  claim 16 , wherein welding the crown part and the outer part together comprises one or more of friction welding, shielded active gas welding, shielded metal arc welding, gas tungsten arc welding, gas metal arc welding, flux-cored arc welding, submerged arc welding, electroslag welding, and electric resistance welding. 
     
     
         19 . The method of  claim 16 , wherein welding the crown part and skirt part together comprises induction heating of the crown part and the skirt part. 
     
     
         20 . The method of  claim 16 , wherein welding the skirt part and the outer part together comprises induction heating of the skirt part and the outer part. 
     
     
         21 . The method of  claim 16 , further including forming ring grooves in the first and second belt regions. 
     
     
         22 . The method of any of  claims 15 - 21 , wherein the crown part further comprises an end surface with means for forming a combustion chamber with an end surface of an opposing piston in a cylinder of an opposed-piston engine, the combustion chamber including an axis, and further wherein welding the crown part and skirt part together comprises orienting the combustion chamber forming means axis to the longitudinal wristpin bore axis with a predetermined angle between the two axes. 
     
     
         23 . A piston of an opposed-piston engine, comprising:
 a crown part comprising an end surface including means for forming a combustion chamber with an end surface of an opposing piston in a cylinder of an opposed-piston engine, and a circumferentially-extending compression ring belt region with one or more ring grooves;   a skirt part comprising a sidewall, a first end, a second end, and a wristpin bore, formed in the sidewall;   an outer part comprising a circumferentially-extending oil ring belt region with one or more ring grooves;   first weld seams connecting the crown part with the first end of the skirt part; and   a second weld seam connecting the second end of the skirt part with the outer part;   in which the compression ring belt region is coaxially aligned with the oil ring belt region along a longitudinal axis of the piston.   
     
     
         24 . The piston of  claim 23 , wherein the crown part further comprises an undercrown and the skirt part further comprises an interior wall situated within the sidewall near the first end, in which the first weld seams include:
 an inner weld seam between a radially inner circumferential surface on the interior wall and a corresponding inner circumferential surface on the undercrown; and,   an inner weld seam between a radially outer circumferential surface on the interior wall and a corresponding outer circumferential surface on the undercrown.   
     
     
         25 . The piston of  claim 24 , the sidewall defining a piston longitudinal axis, wherein the first weld seams are aligned in a planar cut of the piston which is orthogonal to the piston longitudinal axis. 
     
     
         26 . The piston of  claim 23 , wherein the crown part and the skirt part are registered with respect to an axis of the wristpin bore. 
     
     
         27 . A piston of an opposed-piston engine, comprising:
 a crown part comprising an end surface including means for forming a combustion chamber with an end surface of an opposing piston in a cylinder of an opposed-piston engine, and a circumferentially-extending compression ring belt region with one or more ring grooves;   a skirt part comprising a sidewall, a first end, a second end, and a wristpin bore, formed in the sidewall; and,   an outer part comprising a circumferentially-extending oil ring belt region with one or more ring grooves;   in which the crown part is connected to the first end of the skirt part by one of welding, threading, and press fitting; and,   in which the second end of the skirt part is connected to the outer part by one of welding, threading, and press fitting