Equipment
EQUIPMENT
JOHN BAXTER
Powering2012
A
fter years of emissions hurdles and technology evolutions the current 2010 compliant
engines deliver better fuel economy, will likely last longer, and, in some cases, offer
longer oil change intervals than past engines. The following is a quick guide to what
is being offered today from the major engine manufacturers in the Class 8 market.
CUMMINS
Cummins’ ISX15 was introduced in
1998. Design of its block was
optimized through
new electronic
tools to
minimize
noise and
weight.
The engine
also had an
integrated
engine brake.
The cylinder liners got an
improved hardISX15
ening process in
2002 because exhaust gas recirculation can cause corrosion of the wear surface. Also, the piston pin was
supplied with lube oil under pressure to allow the piston to carry the additional cylinder pressure of EGR.
The harder liners actually extended life. Other features
include a combination full-flow and bypass oil filter
from Cummins Filtration.
In 2007, a new combustion chamber was introduced. It stirs up the air around the fuel sprays to allow
increased EGR levels with less air. The result was little
or no increase in cylinder pressure while other engines
were forced to handle more pressure in their cylinders.
2010 brought a new injection system, the XPI
common rail design. The original, simple ISX fuel system
was not able to split
each injection cycle
ISX15
into separate shots of
HORSEPOWER: 400-600
fuel. The XPI system
TORQUE: 1,450-2,050 lb.-ft.
BORE AND STROKE: 5.4 in. by 6.7 in.
allows a “pilot” shot
DISPLACEMENT: 15 liters
of fuel early in comLUBE OIL CAPACITY: 14 gallons
pression to produce
much quieter and
faster ignition, and enables each main shot of fuel to be
split up, to reduce nitrogen oxide (NOx) and soot. It provides fuel pressure independent of rpm to a large pipe, or
12 TRUCKERS NEWS JANUARY 2012
common-rail. Maximum injection pressure even below
the torque peak means a better torque curve, improved
fuel economy, less soot for the DPF to handle, and faster,
quieter cold starts.
Equipping 2010 and 2011 models with Cummins Filtration’s own integrated DPF and SCR system with a
copper-zeolite catalyst means less EGR and more favorable engine tuning. This gives 3 to 5 percent better fuel
economy, depending on the application.
Cummins also offers the ISX 11.9-liter engine, which
has the XPI fuel system and a rear-driven camshaft. It
offers maximum ratings of 425 horsepower and 1650
lb.-ft. of torque.
DETROIT DIESEL
Detroit Diesel, which will be
rebranded as Detroit later
this spring, and its parent company, Daimler
AG, developed the
DD13, DD15 and
DD16. The DD16
is an owner-operator/heavy-haul
version of the
platform displacing
15.6 liters.
The 15- and 16-liter
versions have a turbo-compounding system, says Admir
Kreso, senior engineering manDD16
ager at Detroit. The turbo-compounding turbine sits behind the regular turbo, but instead
of driving a compressor for the intake air, it drives the
crankshaft through hydraulics and a geartrain. It recovers
energy that would otherwise be lost, so, in addition to saving fuel, it increases power output.
The turbo-compounding system also provides the
exhaust backpressure necessary to make the EGR system work without a variable geometry turbo. So the
DD16 also uses a simple, non-wastegate turbo, which is
claimed to provide quick throttle response.