Fordiesel69
Member
For SCUT's we escaped the DEF requirment back in 2012 and im now curious what the deal is now.
2023 What HP is the max you can purchase before it is required to have a DEF.
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ericm979
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No one uses DEF below 75hp. The standard does not define the technology, just the limits it needs to reach. I think there are some machines > 75hp that do not use DEF but meet the Tier IV standard.
Between 25.5hp and 75hp the limits are easier. Most machines use EFI and a DPF+DOC but some don't use EFI and some only use a DOC. Below 25.5hp it's easier still and can be met with mechanical injection timing and combustion chamber shape.
Tier IV has not changed since it was mandated. I think there is a Tier V in the works but so far it's just for Europe.
Between 25.5hp and 75hp the limits are easier. Most machines use EFI and a DPF+DOC but some don't use EFI and some only use a DOC. Below 25.5hp it's easier still and can be met with mechanical injection timing and combustion chamber shape.
Tier IV has not changed since it was mandated. I think there is a Tier V in the works but so far it's just for Europe.
Rustyiron
Super Member
I think that there was a tier 4 and now were into tier4 "final".
Not that I can tell you the difference between the two or even if I'm correct.
Not that I can tell you the difference between the two or even if I'm correct.
alwaysworking
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I was told 75 and up have DEF by my dealer.
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That is correct (for now at least), but all the little ones will still have SCR cannisters and most are common rail HP injection with electronic controls. Why I hang on to my T3 final units. 100% mechanical.
ericm979
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I think that there was a tier 4 and now were into tier4 "final".
Not that I can tell you the difference between the two or even if I'm correct.
There was a Tier IV interim starting in 2008. Final was in 2012-2015.
This is a useful chart:
Emission Standards: USA: Nonroad Diesel Engines
(actually the whole site is useful if you're interested in diesel technology)
PM is Particulate Matter, i.e. soot. Which causes cancer. It's what the DPF and DOC are for. DEF (urea) works with a catalyst to reduce NOx.
SCR is the process by which DEF is used to convert NOX into nitrogen, oxygen, and carbon dioxide. The canister you speak of on <75 hp machines is the DOC, which converts carbon monoxide, hydrocarbons, and some particulate matter into carbon dioxide and water.