Uni project: Manufacturing of turbocharger
JaCkNesS
08-04-2004, 10:36 AM
Hey guys, Im a first year uni student and I've just got an assignment on the manufacturing of a product. Having a huge interest in cars and the automotive field, I chose the turbocharger.
I was wondering if anybody could provide me information on how a turbocharger is made from:
materials
casting/moulding
machining
treatments (heat/chemical etc.)
Assembly of parts
Basically the whole manufacturing process of a turbo charger.
Thanks
I was wondering if anybody could provide me information on how a turbocharger is made from:
materials
casting/moulding
machining
treatments (heat/chemical etc.)
Assembly of parts
Basically the whole manufacturing process of a turbo charger.
Thanks
Neutrino
08-04-2004, 08:27 PM
Hey guys, Im a first year uni student and I've just got an assignment on the manufacturing of a product. Having a huge interest in cars and the automotive field, I chose the turbocharger.
I was wondering if anybody could provide me information on how a turbocharger is made from:
materials
casting/moulding
machining
treatments (heat/chemical etc.)
Assembly of parts
Basically the whole manufacturing process of a turbo charger.
Thanks
If you would look at the top of the forum in Turbo 101 you'll find some good info.
Anyway as far as materials go for the exaust side, a cast iron housing with iconel turbine wheels should make an excellent combination to whitstand hight temps and numerous heat cycles. Some companies like to use ceramic wheels to keep their mass to a minimum therfore reducing inertia.
Conecting the turbine you might want to use a sleeve bearing to kep the cost down, although the best way would be water cooled ball bearing.
For the compressor , I don't think materials are as important as in the exaust portion since they don't have to deal with the extreme heat but some nice lightweight materials that resist corosion would be perfect. Perhaps a stainless steel compressor housing with a titanium compressor wheel should make a good match.
You could also try calling turbonetics or some other companies and see if you could speak with one of their engineers.
I was wondering if anybody could provide me information on how a turbocharger is made from:
materials
casting/moulding
machining
treatments (heat/chemical etc.)
Assembly of parts
Basically the whole manufacturing process of a turbo charger.
Thanks
If you would look at the top of the forum in Turbo 101 you'll find some good info.
Anyway as far as materials go for the exaust side, a cast iron housing with iconel turbine wheels should make an excellent combination to whitstand hight temps and numerous heat cycles. Some companies like to use ceramic wheels to keep their mass to a minimum therfore reducing inertia.
Conecting the turbine you might want to use a sleeve bearing to kep the cost down, although the best way would be water cooled ball bearing.
For the compressor , I don't think materials are as important as in the exaust portion since they don't have to deal with the extreme heat but some nice lightweight materials that resist corosion would be perfect. Perhaps a stainless steel compressor housing with a titanium compressor wheel should make a good match.
You could also try calling turbonetics or some other companies and see if you could speak with one of their engineers.
SaabJohan
08-06-2004, 01:24 PM
The turbine house is made in cast iron, usually some special iron like Ni-resist. In some high performance applications thin walled stainless is used.
The radial inflow turbine is investment cast using superalloys like Inconel. However, in the later high temperature resistant turbines other materials are used, like Mar-M 247 which is a directionally solified alloy. Ceramic turbines can't handle any higher boost pressures since that causes high tensile stress in the turbine which the caramic won't handle so ceramic is very rare. The turbine is then machined and electron beam welded onto the shaft.
The piston ring seals are made of tool steel, the heat bearing house heat shield can be cast or made of sheetmetal (usually in sheetmetal).
The bearing house is usually made of cast iron, there are some cases I believe when the house was made in aluminum. Usually three fully floating bearings are used. There are usually two radial bearings and one axial bearing. The turbine axle floats on an oil film in the radial bearing and the radial bearing floats on an oil film in the bearing house as this reduce the difference in velocity and the shear stress of the oil.
The radial bearings are kept in place by clips and the axial bearing is usually screwed. All axial bearings are however not screwed to the bearing house, those turbochargers are usually not suitabel for higher boost pressures. The axial bearing can also be a 360 degree bearing or say a 270 degree bearing; in the first case the bearing covers all 360 degrees around the axle while the 270 degree bearing has an opening in the bearing. 360 degree bearings should be used in high boost applications.
In some cases ball bearings are used. Turbonetics use a single ball bearing instead of the stock axial bearing. Manufacturers like Garrett and IHI uses a double bearing setup to take up all radial and axial forces and offer the lowest friction. The bearings used have balls of ceramic, Garrett then uses bearing races in M50 material and retainers from silicon-bronze.
The impeller is usually made in aluminum, some high pressure ratio compressors are made in titanium. The impellers are usually cast, but there are a few machined impellers. Until a few years ago all titanium impellers where machined until Holset started a serial production of cast titanium impellers (titanium is difficult to cast). The compressor house is usually cast aluminum, racing turbos can used cast magnesium instead.
Some high performance turbochargers also have a speed sensor measuring the rpm of the turbocharger.
Usually the turbocharger is attached to the exhaust manifold by bolts just like the turbine house is attached to the bearing house, with the case of racing units v-bands are often used, these are also found sometimes on production units too.
Racing turbochargers often use a heat shield around the bearing house and exhaust manifold, these can be made by activated carbon cloth with some sort of metal foil around. Scattershields of kevlar are under development.
Garrett TR30R on a Audi R8 engine
http://www.mulsannescorner.com/Audi-JK9.jpg
The TR30R turbocharger offer much of the lastest technology with its Mar-M 247 turbine, heat shielded thin wall stainless turbine housing, twin ball bearings, turbo speed sensor and so on. It's fitted with a restricot according to the regulations and ceramic materials and variable geometry aren't allowed. This is the same turbocharger model used by several teams in the world rally championship. One of these turbochargers are very expensive, above 10,000 us dollars should not surprise me.
The radial inflow turbine is investment cast using superalloys like Inconel. However, in the later high temperature resistant turbines other materials are used, like Mar-M 247 which is a directionally solified alloy. Ceramic turbines can't handle any higher boost pressures since that causes high tensile stress in the turbine which the caramic won't handle so ceramic is very rare. The turbine is then machined and electron beam welded onto the shaft.
The piston ring seals are made of tool steel, the heat bearing house heat shield can be cast or made of sheetmetal (usually in sheetmetal).
The bearing house is usually made of cast iron, there are some cases I believe when the house was made in aluminum. Usually three fully floating bearings are used. There are usually two radial bearings and one axial bearing. The turbine axle floats on an oil film in the radial bearing and the radial bearing floats on an oil film in the bearing house as this reduce the difference in velocity and the shear stress of the oil.
The radial bearings are kept in place by clips and the axial bearing is usually screwed. All axial bearings are however not screwed to the bearing house, those turbochargers are usually not suitabel for higher boost pressures. The axial bearing can also be a 360 degree bearing or say a 270 degree bearing; in the first case the bearing covers all 360 degrees around the axle while the 270 degree bearing has an opening in the bearing. 360 degree bearings should be used in high boost applications.
In some cases ball bearings are used. Turbonetics use a single ball bearing instead of the stock axial bearing. Manufacturers like Garrett and IHI uses a double bearing setup to take up all radial and axial forces and offer the lowest friction. The bearings used have balls of ceramic, Garrett then uses bearing races in M50 material and retainers from silicon-bronze.
The impeller is usually made in aluminum, some high pressure ratio compressors are made in titanium. The impellers are usually cast, but there are a few machined impellers. Until a few years ago all titanium impellers where machined until Holset started a serial production of cast titanium impellers (titanium is difficult to cast). The compressor house is usually cast aluminum, racing turbos can used cast magnesium instead.
Some high performance turbochargers also have a speed sensor measuring the rpm of the turbocharger.
Usually the turbocharger is attached to the exhaust manifold by bolts just like the turbine house is attached to the bearing house, with the case of racing units v-bands are often used, these are also found sometimes on production units too.
Racing turbochargers often use a heat shield around the bearing house and exhaust manifold, these can be made by activated carbon cloth with some sort of metal foil around. Scattershields of kevlar are under development.
Garrett TR30R on a Audi R8 engine
http://www.mulsannescorner.com/Audi-JK9.jpg
The TR30R turbocharger offer much of the lastest technology with its Mar-M 247 turbine, heat shielded thin wall stainless turbine housing, twin ball bearings, turbo speed sensor and so on. It's fitted with a restricot according to the regulations and ceramic materials and variable geometry aren't allowed. This is the same turbocharger model used by several teams in the world rally championship. One of these turbochargers are very expensive, above 10,000 us dollars should not surprise me.
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