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fuel efficiency compared to Tier 3, depending on duty
cycle and machine optimization. Fuel efficiency will be
further increased for Tier 4 final 2014 by as much as 4%,
Last month at OTC, Cummins announced that its Tier 4
final off-highway 2015 emissions technology above 751 hp
will be a combination of clean in-cylinder combustion and
a new SCR exhaust system. The new SCR system will be
utilized on the next generation of 19 to 60 L QSK engines
across the 800 to 3000 hp power range. The system will
be scaled up for QSK engines above 3000 hp, including
the new larger-displacement engine platform.
The Tier 4 final technology is engineered to bring a
common Cummins emissions architecture to a diverse
range of high-horsepower applications, including mining, locomotives, marine vessels, oil and gas equipment, power generation, large cranes and other industrial equipment.
For most applications, the Tier 4 final QSK engine and
integrated SCR aftertreatment will be a drop-in replacement for the current QSK engine and exhaust muffler, with
a similar size and equivalent noise reduction, Cummins
said. While achieving low emissions, Cummins said its
Tier 4 final technology also reduces the overall cost of
operation, with QSK fuel efficiency improved by 5 to 10%,
depending on the equipment duty cycle.
By focusing NOx reduction within the exhaust rather
than during in-cylinder combustion, Cummins said it
avoids the need to make any major change to the external
engine platform. In-cylinder technology includes higher-pressure fuel injection and enhancements to the power
cylinder design. PM reduction in-cylinder eliminates the
need for either a diesel oxidation catalyst (DOC) or DPF
aftertreatment in the exhaust stream.
Cummins added that the fuel savings achieved by the
Tier 4 final QSK engines more than offset the cost of diesel exhaust fluid (DEF) dosing required for the functioning
of the SCR clean exhaust system. Depending on duty
cycle and application, Cummins combustion technology
for Tier 4 final enables fuel efficiency to be improved by 5
to 10% compared with Tier 2 engines, with DEF consumption to fuel held as low as 2 to 3%.
More details on the new Tier 4 products will be included
in an upcoming issue of Diesel Progress.
On the on-highway engine side, Cummins said its ISX15
engine has demonstrated a 6% fuel economy improvement over the 2007 version. The fuel economy gain is the
result of optimized combustion and improved calibrations,
the company said.
Production volumes for EPA 2010 on-highway engines
surpassed 60,000 units for the first 12 months of full pro-
duction and totaled over 100,000 units through April 2011,
the company said.
Cummins said it has received EPA certification for its
G8.3E, QSL9G, G855E and GTA855E stationary natural
gas engines. These natural gas engines are certified to
EPA Spark Ignition New Source Performance Standard
(SI NSPS) 40CFR60, Subpart JJJJ standards, and are
capable of meeting more stringent emissions regulations, such as the Texas Commission on Environmental
Quality Chapter 117 requirements for ozone nonattainment areas, Cummins said. To meet these standards,
Cummins is again employing the use of a three-way
catalyst to reduce all of the regulated emissions constituents. The use of the catalyst allows the engines to
meet the NSPS requirement for engines 100 to 499 hp.
continued on page 38
36 DIESEL PROGRESS NORTH AMERICAN EDITION June 2011