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Understanding Interim Tier 4 Emissions
Compliance Without Sacricing Performance
Why the change? New federal emissions regulations require a
90% reduction in particulate matter and a 50% drop in nitrogen
oxides.
How do new engines meet these stringent requirements?
Engines 75hp and above use a catalyzed exhaust lter that
contains a Diesel Oxidation Catalyst (DOC) and a Diesel
Particulate Filter (DPF). Under normal operating conditions, the
DOC reacts with exhaust gases to reduce carbon monoxide,
hydrocarbons, and some particulate matter. The downstream
DPF forces exhaust gases to ow through porous channel walls,
trapping and holding the remaining particulate matter (soot).
The trapped particles are eventually oxidized through a cleaning
process called Regeneration.
What is Passive Regeneration? Passive Regeneration is a
natural cleaning process that occurs when the temperature, load
and speed produce exhaust heat that oxidizes the particulate
matter in the DPF under normal operating conditions and turns it
to ash.
What is Active Regeneration? If Passive Regeneration cannot
be achieved due to low temperature, load, or speed, the engine
will automatically adjust to increase the exhaust temperature to
oxidize the particulate matter. This is done by tuning the amount
of air intake, adjusting injection timing, and injecting a small
quantity of fuel into the exhaust stream. An Active Regeneration
usually takes about a half an hour to complete.
What does the inhibit switch do? The inhibit switch prevents
the engine from performing an Active Regeneration. The switch
should only be used for special locations where high exhaust
temperatures would be a danger. For most applications the
switch should be left in the auto Position.
What is a Forced Regeneration? After operating with the
inhibit switch on it may be necessary to manually tell the engine
to perform a regeneration. Holding the inhibit switch up for 5
seconds will force an Active Regeneration to occur.
How long will a DPF last? John Deere DPF lters are designed
to operate for at least 5000 hours before needing removal
for cleaning out accumulated ash. Some eld units have
experienced 7000 hours or more before requiring service.
Diesel Particulate Filter (DPF) System
Catalyzed Exhaust Filter
Diesel Particulate Filter (DPF)
Remaining particulate matter entrapped in the DPF are oxidized
through a continuous cleaning process called passive regeneration
Diesel Oxidation Catalyst (DOC)
is part of the DPF system where exhaust gases are transformed to
reduce carbon monoxide, hydrocarbons, and some particulate matter
Cleaner diesel exhaust
with lower particulate
matter comes out
Diesel exhaust with heavy
particulate matter goes in
EPA Compliance Without Sacricing Performance
Generac Mobile Power generators meet the new federal emissions regulations without sacricing power and reliable
performance. Powered by EPA compliant Interim Tier 4 engines; the mobile generators 75hp and above use a catalyzed
exhaust lter containing a Diesel Oxidation Catalyst (DOC) and a Diesel Particulate Filter (DPF) to reduce carbon monoxide,
hydrocarbons and particulate matter.
Regeneration Operator Interface
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