Diesel deadline looms
By Mark Stasell
With the deadline just 15 months away, tighter diesel-emissions
regulations that will take effect in 2007 continue to the shape business plans and strategies of the fuel oil industry, diesel-engine manufacturers and United States commercial truck and school bus operators.
These groups now share a defined commitment to clean-air initiatives not only because they are mandated, but also because they are right and because they are good business.
In February, Allen Schaeffer, executive director of the Diesel Technology Forum, said, “Thanks to a remarkable industry-wide investment in the research and development of state-of-the-art engines, cleaner-burning fuels and effective exhaust-control devices, manufacturers have developed clean-diesel systems that are virtually emissions-free.”
Two notable examples of this cooperation include:
In 2000, International Truck and Engine Corporation introduced its Green Diesel Technology, the industry’s leading low-emitting diesel technology. A year later, this
technology became the first certified by the Environmental Protection Agency and the California Air Resources Board as achieving the virtually zero levels of hydrocarbon and particulate matter emissions (soot), a whole six years ahead of federal requirements. Today, hundreds of no-smoke, no-smell Green Diesel Technology buses operate throughout California. This technology platform is proven over five years of extensive research, development and real-word performance.
In late 2003, diesel-engine manufacturers found it was feasible to reduce in-cylinder emissions of nitrous oxides (NOx) to a level that reduces the burden on after-treatment in meeting the 2007 standards. In our company’s case, for instance, all diesel engines for the 2007 model year will meet the federal NOx requirements without the need for complex selective catalytic reduction (SCR) technology. SCR is an after-treatment technology that requires the availability of urea, an ammonia compound, and its introduction into the exhaust system. SCR requires special infrastructure for delivery of an additional fluid to the vehicle, adding another level of complexity for fuel distributors and truck operators.
These significant technological breakthroughs on the engine-manufacturing side were, however, made possible only in tandem with the commitment of refiners to ultra-low-sulfur diesel fuel in which sulfur has been reduced to fewer than 15 parts-per-million. ULSD fuel, in turn, allows truck and bus operators to continue to reap the capability and efficiency benefits of diesel power versus gasoline and alternative-fuel engines.
So what concerns remain about 2007 emissions? It basically boils down to one: Truck and bus fleet owners and operators do not want to sacrifice engine performance in the era of tighter emissions.
The good news is they won’t have to. However, diesel-engine manufacturers and truck-makers still must address perceptions that adding environmental technologies will somehow offset the long-established advantages of diesel power. Here are a few ways we are aggressively addressing engine performance while reducing emissions:
Many manufacturers are starting to use variable geometry turbochargers, which improve engine responsiveness and efficiency by allowing for an improved supply of air to the engine. This adjustable airflow allows the turbocharger to act like a small turbo for instant response at low speeds and works as a large turbo when more airflow is needed at full power.
Exhaust Gas Recirculation
Exhaust gas recirculation, or EGR, is another common technology path used by the majority of diesel-engine manufacturers. EGR recirculates some of the exhaust gas into the engine intake to help reduce peak temperatures in the cylinder where oxides of nitrogen (NOx) are formed. Cooled temperatures reduce NOx
production, which also reduces smog in the environment.
The demands on fuel systems continue to increase, as well. Increased fuel injection pressures will continue to help control particulates prior to any after-treatment, and improved timing strategies and control of injection events are substantial contributors to the 2007 reductions in NOx emissions and engine noise.
One of the primary components for reducing diesel-engine emissions is the widespread availability of ULSD fuel. From a vehicle standpoint, reduced sulfur content is an absolute necessity to reduce emissions to the regulated levels without poisoning the diesel particulate filters.
Oil companies have taken a progressive lead in providing ultra-low-sulfur fuel on a limited basis and are currently conducting experiments with pipeline companies to ensure the widespread availability for all 2007 model-year products.
Manufacturers are and will continue to conduct extensive tests of these technologies, in the lab and on work sites in actual fleets. Most 2007 engines will be in test fleets beginning this September. As the results of this testing become known, the trucking industry will gain confidence that diesel-engine manufacturers will deliver what we at International are thinking of as “pure power and power that is pure.”
Meeting 2007 emissions regulations has been a priority for everyone involved and there will be a huge payoff; there will be no smoke and no smell coming from 2007 products, and the changes will have no effect on engine performance.
Mark Stasell is the vice president of engine engineering and product development for the International Truck and Engine Corporation. He can be reached by calling (800) 448-7825.