2007 Emissions Update
May 1, 2005
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2007 Emissions Update
David
Kolman
Diesel engine manufacturers say they are ready to meet the U.S. Environmental Protection Agency’s more stringent 2007 emissions standards for on-highway diesel engines. While the technologies being employed vary, the new engines should provide the same reliability, performance and durability.
Meantime, diesel engine oil formulations are being
changed to help meet the 2007 regulations. The phase-in for the EPA’s
mandated ultra-low-sulfur diesel fuel, required for the 2007 engines,
begins in June of next year.
Here is a brief overview of what engine manufacturers
are doing to meet the 2007 regulations:
Caterpillar is
building on its ACERT (Advanced Combustion Emission Reduction Technology)
engines, using an enhanced combustion process called Clean Gas Induction
(CGI), closed crankcase ventilation system and diesel particulate filter
system with active regeneration. Engines with 500 hp or less will require
one diesel particulate filter; engines with 550 or more horsepower will
require dual filters. Developed to meet the 2004 emissions standards, ACERT
uses series turbochargers, variable valve control, high-pressure multiple
injection fuel system, electronics control system and oxidation catalyst.
Cummins is using its
current cooled exhaust gas recirculation (EGR) technology and integrating
its own particulate filter, designed to replace the existing vehicle
muffler. Its 2007 engines will also feature a crankcase ventilation system.
Detroit Diesel is further
advancing its EGR technology, in addition to integrating a diesel
particulate filter, maintenance-free closed crankcase breather system and
improved turbocharger.
International Truck & Engine is using its Green Diesel Tech-nology, an emissions
technology platform that provides the flexibility to design
application-specific solutions using advanced air management, selected fuel
system application, proprietary combustion strategies, electronic controls
and optimized after-treatment solutions. At the heart of the technology is
its engine with advanced hydro-electronics and a catalyzed regenerative
diesel particulate filter that replaces the ordinary muffler.
Mack Trucks is also
using technology based on exhaust gas recirculation, plus a diesel
particulate filter system. The technology has been developed from its
experience with its ASET (Application Specific Engine Technology) engine
family, which features electronic unit pump injection and V-MAC
electronics.
Volvo Trucks has
introduced its Variable Pulse (V-Pulse) Technology. With the new V-Pulse
engines, the exhaust gases created by the exhaust valves are captured and
the exhaust pulses push up to 30 percent of the exhaust through the EGR
cooler in two separate intervals. This technology allows Volvo to continue
to use a conventional turbocharger.
Volvo and Mack, a member of the Volvo Group, will have
a new global engine platform by 2007. While the platform will share common
architecture and technology, engines will be customized for each brand. The
new platform will feature high-pressure fuel injection, single-stage
variable geometry turbocharger and rearranged EGR cooler with a diesel
particulate filter integrated with a larger muffler.
Engine oils
As a consequence of the 2007 emissions regulations,
the composition of diesel engine oil has to be modified to deal with the
coming lower sulfur content of diesel fuel and emissions control
technology. The new engine oil formulation, called PC-10, is being designed
to maintain the protective and lubricating properties of engine oil and not
affect emission controls downstream of the engine.
The new oils will be backward-compatible so fleets can
use just one oil for both 2007-compliant and older generation engines.
Ultra-low sulfur diesel fuel is a specially refined diesel fuel that has
significantly lower sulfur content than regular on-highway diesel. Using
ultra-low sulfur diesel will contribute to dramatic reductions in diesel
emissions because the lower sulfur content produces fewer sulfate emissions
within the particulate matter in the exhaust, and it enables use of
emission reduction equipment, like particulate traps and catalytic
converters to lower emissions of particles and nitrogen oxides.
The fuel is expected to have virtually the same energy
and performance as today’s highway diesel. However, it will be more
expensive, anywhere from $0.05 to $0.50 more per gallon. BI
David Kolman is a veteran truck communicator, keynote
speaker and long-haul trucker. Commissioned as an Honorary Colonel on the
Kentucky governor’s staff for his work promoting traffic safety, he
actively participates in trade associations and reports news and
information about the trucking industry for broadcasting and print media.
Emissions technology terms
• Exhaust Gas Recirculation (EGR) — These systems accomplish emissions reduction
by capturing exhaust gases and returning them to the engine’s
combustion cycle along with fresh air and fuel. The recirculated exhaust
reduces combustion temperature, which reduces the formation of NOx.
• Clean Gas Induction (CGI) — This system draws clean inert gas from downstream of
the particulate filter, after it has been filtered and cooled, and returns
it to the intake air system. The intake air is soot-free, which helps
engine wear, and its low intake manifold gas temperature contributes to
lower NOx emissions.
• Exhaust particulate traps — These 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.
• Closed crankcase ventilation systems
— In these systems, rather than venting the particulate matter
emissions from the engine’s crankcase breather into the atmosphere,
this “blow-by” is routed into the air intake system. Crankcase
blow-by is produced when combustion gases, under high pressure, become
contaminated with oil mist when blown past the piston rings into the crankcase.
The regulations
The tougher 2007 emissions regulations demand that
both particulate matter and oxides of nitrogen
(NOx) emissions be reduced. The new NOx level is nearly 55 percent lower
than today’s standard, and there is a tenfold reduction in
particulate matter.
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.
The U.S. Environmental Protection Agency has decreed
that by June 2006, at least 80 percent of on-highway diesel fuel sold will
be ultra-low sulfur diesel; by 2010, all on-highway diesel fuel must be
ultra-low sulfur.
The Canadian government is requiring that all diesel
fuel sold in Canada for on-highway use will have to be ultra-low-sulfur as
of October 2006. There are no fuel and emissions regulations in Mexico at
this time.
