Low-emission diesel engines – an equipment roundup
Truck and engine
manufacturers appear to be on target to
introduce new, cleaner diesel engines. The engines are being developed to
meet the U.S. Environmental Protection Agency’s new, more stringent
diesel emissions standards that go into effect in 2007 and 2010.
The 2007 regulations demand that both particulate
matter and oxides of nitrogen emissions be reduced by 90 percent from
Particulate matter is
formed by the incomplete combustion of fuel in diesel engines. Oxides of
nitrogen are formed in small amounts during combustion as a result of the
combination of nitrogen and oxygen in the presence of high temperatures and
pressures. Oxides of nitrogen are collectively referred to as
“NOx”, where “x” represents a changing proportion
of oxygen to nitrogen.
Engine makers Cummins, Detroit Diesel, International,
Mack and Volvo have all reported that they will use cooled exhaust gas
recirculation (EGR), along with diesel exhaust particulate traps, to meet
the 2007 standards. Previous reductions in particulate matter emissions had
been achieved through engine combustion improvements and oxidation
EGR systems capture exhaust gases, pass them through a
cooler and then mix them with the incoming air charge to the cylinder. This
adds heat capacity and reduces oxygen concentration in the combustion
chamber by diluting the incoming air with the cool exhaust gases. During
combustion, this has the effect of reducing the combustion temperatures,
which in turn, reduces NOx emissions.
Exhaust particulate traps filter and
“catch” the particulate matter from the exhaust stream and
prevent these particles from reaching the atmosphere. Over time, these
traps “fill up” and need to be periodically
“cleaned” by means of a regeneration process, otherwise the
engine’s performance and fuel economy is adversely affected. This
regeneration process is typically achieved by “burning off” the
trapped particulate matter.
Caterpillar is the only engine manufacturer to use a
different technique to reduce emissions. Its process is called ACERT, which
stands for Advanced Combustion Emission-Reduction Technology. It employs a
mix of injection, combustion and electronic tools, along with exhaust
Interestingly, none of the filtration technologies
planned for the new 2007 exhaust emissions standards will function with
today’s diesel fuel. Consequently, the U.S. EPA has decreed that
beginning Sept. 1, 2006, ultra-low-sulfur diesel fuel must be available
nationwide. Fuel low in sulfur produces less
particulate matter from combustion.
This fuel standard will be phased in through Sept. 1,
2010. The sulfur content of this new fuel will be dramatically reduced,
from 500 parts per million (ppm) to just 15 ppm.
If that were not challenging enough for the petroleum
industry, the new ultra-low-sulfur diesel fuel requires different and
additional refining methods, transportation means and storage facilities.
All of this will, obviously, push up fuel prices. How much is
anyone’s guess, although Cummins has projected the increase to be around
$0.05 per gallon.
New specifications are being developed for lubrication oil compatible with the
new 2007 and 2010 low-emissions diesel engines.
Real-world tests of the 2007 engines are expected to
get underway sometime next year. The testing will be conducted with
prototype, pre-production engines. This will give the engine and truck
manufacturers the time and leeway to work out the inevitable problems that
accompany any new technology.
It is a given that the new emissions-compliant diesel
engines are going to be more expensive. Here again, no one knows just how
much more. Estimates range all across the board, from a low of $1,500 to a
high of $10,000.
Another unknown is how these engines will perform.
Reliability, durability, driveability, performance, fuel consumption and operating and maintenance costs will be determined through
time and experience.
ArvinMeritor has launched
its Technical Training and Product Service Web site to provide training and
service information on its Meritor, Meritor WABCO and Gabriel brand
International has introduced what it claims is the
“world’s biggest production pick-up truck for commercial
business owners.” Based on International’s severe-service
trucks, the CXT comes standard with all-wheel drive, air brakes, crew cab
that seats five, International DT 466 diesel engine and Allison automatic
Kenworth had the highest ranking in customer
satisfaction among vocational Class 8 truck owners, according to J.D. Power
and Associates’ 2004 Heavy Duty Truck
Customer Satisfaction Study. Areas studied
included ride, handling, serviceability, visibility and ease of entry and
National Truck Equipment Association’s revised Truck Equipment Handbook contains
technical and regulatory information on commercial vehicles, and has a
comprehensive glossary of truck equipment terminology. To order, call
Peterbilt’s Model 335 is now available with the
two-pedal automated Eaton six-speed UltraShift transmission (driver uses
only an accelerator, brake and dash-mounted controls to initially engage
forward or reverse); Models 357, 378, 379 and 385 are available with
drivetrain combinations of Allison automatic transmissions and all
heavy-duty Cummins and Caterpillar engines. peterbilt.com
Shell’s Rotella Extended Life Coolant Kit can
switch a heavy-duty diesel engine from standard coolant to organic-based
extended life coolant without having to completely drain and refill the
cooling system. rotella.com
Volvo Trucks North America has revamped its Web site,
adding a variety of new features and additional information on vehicles,
services, F&I, training, etc. volvotrucks.us.com