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Aftertreatment - Precious Metals
- Thread starter ivymike
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Alternatively, if I knew that the catalyst element was 11.5" diameter and 3.5" thick, and that the precious metal loading was 20g/cuft, and that the platinum and rhodium were used in a 4:1 ratio, then I could calculate that the volume is 0.210ft3, the total mass of precious elements is 4.21g, and that 0.84g of that is rhodium, while 3.37g is platinum.
What I don't know is whether the final result makes sense - one thing that I worry about is whether the external dimensions of the catalyst element give an appropriate volume for the precious metals loading calculation (20g/cuft based on external dimensions? based on some sort of pore volume? based on ?)
What I don't know is whether the final result makes sense - one thing that I worry about is whether the external dimensions of the catalyst element give an appropriate volume for the precious metals loading calculation (20g/cuft based on external dimensions? based on some sort of pore volume? based on ?)
patprimmer
New member
If you can afford destructive testing, any metallurgical lab should be able to do a quantitative analyse for you. The Elmer Perkins type atomic absorption spectrophotometer is a name that seems to be rising from memories of my study of the subject in 1960 something or other.
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eng-tips, by professional engineers for professional engineers
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Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
GregLocock
Automotive
"the total mass of precious elements is 4.21g"
That is a good, possibly high, estimate. You are short one element, palladium typically. The precise proportions of which metal are used is very variable.
Cheers
Greg Locock
SIG
lease see FAQ731-376 for tips on how to make the best use of Eng-Tips.
That is a good, possibly high, estimate. You are short one element, palladium typically. The precise proportions of which metal are used is very variable.
Cheers
Greg Locock
SIG
lease see FAQ731-376 for tips on how to make the best use of Eng-Tips.Pd is replacing Pt quite a bit in newer catalyst designs. It is cheaper and generally can withstand higher temperatures. Manifold-mounted light-off catalysts are generally Pd-only. Destructive testing is probably the only way to know for sure, but under-floor 3-way catalysts with ~0:16:1 Ptd:Rh and ~30-50 g/ft^3 loading were fairly common for California LEV II and Federal Tier 2 vehicles a few years ago. Vehicles sold in Europe generally have less PGM loading due to their reduced km-useful-life requirements relative to the U.S. standards
d:Rh and ~30-50 g/ft^3 loading were fairly common for California LEV II and Federal Tier 2 vehicles a few years ago. Vehicles sold in Europe generally have less PGM loading due to their reduced km-useful-life requirements relative to the U.S. standards- Status