Tiffin Motorhomes ALLEGRO BREEZE, Owner'S Manual

Page: 25 / 76

C U M M I N S E N G I N E S
4-3
EPA Mandates
The Environmental Protection Agency (EPA) mandates that all engines built after December 31, 2009 must
reduce the level of emissions exhausted by the engine to the following levels.
Nitrous Oxides (NOx) – 0.2 g/bhp-hr
Particulate Matter (PM)- .01 g/bhp-hr
To meet EPA guidelines, diesel engines installed in Tiffin Motorhomes PowerGlide chassis for domicile
in Canada and the USA use an after treatment system (ATS) with a diesel particulate filter (DPF)to reduce
particulate matter, and selective catalytic reduction (SCR) technology to reduce NOx downstream of the
engine.
Notice
Using non-specification fluids can result in serious damage to the ATS. It is extremely important that the
following guidelines be met for vehicles with EPA10 thru EPA2017 compliant engines, or damage may
occur to the ATS, and the warranty may be compromised.
• Use "ultra-low sulfur diesel (ULSD)" with 15 ppm sulfur content or less.
• Do not use fuel blended with used engine lube oil or kerosene.
• Engine lube oil must have a sulfated ash level less than 1.0 wt %, currently referred to as CJ-4 oil.
• Use only API certified diesel exhaust fluid (DEF) in the DEF tank.
The ATS is comprised of a diesel oxidation catalyst (DOC), and a diesel particulate filter (DPF). The
DPF traps soot particles, and exhaust heat converts the soot to ash in the DPF in a process called
regeneration (re-gen). The harder an engine works, the better it disposes of soot. When the engine is
running under load and re-gen occurs without input, it is called passive re-gen. If the engine isn’t running
hot enough, the electronic controls may initiate an active re-gen, whereby extra fuel is injected into the
exhaust stream before the DPF, to superheat the soot trapped in the filter and burn it to ash. Both types
of re-gen occur without driver input.
Operating at reduced engine load will allow soot to accumulate in the DPF. When this occurs, the DPF
lamp
illuminates, indicating that a re-gen must be performed, and the driver must bring the vehicle
up to highway speed to increase the load. Driving at highway speeds for 20 minutes should allow for a
re-gen to take place, and turn off the DPF lamp.
After the exhaust stream passes through the DPF, it flows through a second canister housing which is the
SCR device. A controlled quantity of diesel exhaust fluid (DEF) is injected into the exhaust stream where
heat converts it to ammonia (NH
3
) gas. This mixture flows through the SCR device where the ammonia