2007 Emissions Update
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.
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 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.