Turbocharger system subassemblies and associated assembly methods
View Patent ↗A subassembly of a system including an exhaust gas turbocharger system coupled with an internal combustion engine exhaust system, includes first and second components secured to each other, wherein the components are heated to an operational temperature by engine exhaust gases during engine operation. The components are secured to each other by or with a “low-melt material” whose melting temperature is less than the operational temperature, such that the low-melt material melts or at least loses its securing and/or positioning functionality upon operation of the engine and turbocharger system, and thus no longer performs any fastening or positioning function for the components. In some embodiments, temporary fasteners made of or including the low-melt material are employed for temporarily securing and positioning the components.
1. A method for assembling first and second components of a system that includes an exhaust gas turbocharger system coupled with an internal combustion engine exhaust system, wherein the components are heated to an operational temperature by heat transfer from engine exhaust gases during engine operation, the method comprising the step of:
securing the first and second components of the system in predetermined positions relative to each other using a low-melt material whose melting temperature is less than said operational temperature.
2. The method of claim 1 , wherein the securing step employs temporary fasteners comprising the low-melt material.
3. The method of claim 2 , further comprising the step of operating the engine and exhaust gas turbocharger system so as to heat the components at least to said operational temperature and thereby cause the low-melt material to melt whereupon the temporary fasteners no longer perform any fastening or positioning function for the components.
4. The method of claim 1 , further comprising the step, performed after the securing step, of permanently affixing the first and second components to each other by a high-melt material having a melting point temperature substantially higher than said operational temperature.
5. The method of claim 4 , wherein the permanently affixing step comprises engaging threads on one or more permanent fasteners with corresponding threads defined by at least one of the first and second components, the permanent fastener(s) being made of the high-melt material.
6. The method of claim 4 , wherein the permanently affixing step comprises forming one or more metallurgical bonds between the first and second components, the bond(s) being made with the high-melt material.
7. A subassembly of a system that includes an exhaust gas turbocharger system coupled with an internal combustion engine exhaust system, the subassembly comprising:
first and second components that are heated to an operational temperature by heat transfer from engine exhaust gases during engine operation, the first and second components being secured in predetermined positions relative to each other by a low-melt material whose melting temperature is less than said operational temperature such that the low-melt material melts upon operation of the engine and turbocharger system and no longer performs any fastening or positioning function for the components.
8. The subassembly of claim 7 , wherein the first and second components are secured to each other by temporary fasteners comprising the low-melt material.
9. The subassembly of claim 8 , wherein the first component comprises an exhaust manifold that receives exhaust gases from the engine, the exhaust manifold defining an exit passage for the exhaust gases, and the second component comprises a valve assembly mounted on the exhaust manifold, the valve assembly including a valve housing that defines a valve passage in fluid communication with the exit passage of the exhaust manifold.
10. The subassembly of claim 9 , in combination with a turbocharger having a turbine housing, the turbine housing being affixed to the valve housing and the exhaust manifold such that the valve housing is disposed between a surface of the turbine housing and a surface of the exhaust manifold.
11. The subassembly of claim 10 , wherein the valve housing defines holes, the turbine housing defines corresponding holes, and the exhaust manifold defines corresponding holes therein, and the turbine housing and valve housing are affixed to the exhaust manifold by bolts passing through the holes in the turbine housing, through the holes in the valve housing, and through the holes in the exhaust manifold.
12. The subassembly of claim 8 , wherein the temporary fasteners comprise tree fasteners.
13. The subassembly of claim 8 , wherein the temporary fasteners comprise locating pins.
14. The subassembly of claim 7 , wherein the low-melt material has a melting temperature from about 120° C. to about 500° C.
15. The subassembly of claim 7 , wherein the low-melt material is a thermoplastic polymer.
16. The subassembly of claim 7 , wherein the low-melt material is electrically insulative.
17. The subassembly of claim 7 , wherein the low-melt material is a low-melt metal.
18. The subassembly of claim 7 , wherein the low-melt material is a low-melt glass.
19. The subassembly of claim 7 , wherein the first component comprises a center housing of the turbocharger system and the second component comprises a turbine housing of the turbocharger system.
20. The subassembly of claim 7 , wherein the temporary fasteners comprise threaded fasteners.