Caterpillar will stick with ACERT technology for 2007 engines
Jun 1, 2005 12:00 PM
Caterpillar officials said during a press conference at the Mid-America Trucking Show that it will be able to comply with the 2007 Environmental Protection Agency (EPA) emissions regulations using ACERT technology.
“We developed ACERT technology with the goal of meeting all current and future emissions regulations, while continuing to provide the overall value on-highway vehicle owners need to operate profitably,” said Greg Gauger, director, On-Highway Power Systems. “ACERT technology delivers long-term emissions reduction capability and provides all of the key elements of value — reliability, durability, fuel economy, and lower operating costs.”
The 2007 EPA emissions requirements impact on-highway engine design in five areas. First is particulate matter (PM), in which a ten-fold reduction is required — from .10 to .01 grams per horsepower per hour. To meet this requirement, engine manufacturers will need to employ a diesel particulate filter.
Secondly, Cat engines will move from 2.5g/hphr NOx + HC to 1.2g/hphr NOx. This 1.2 figure is based on the phase-in provision, which is allowed by the EPA — the actual requirement is to reduce Nox emissions to .20 by 2010. Third, crankcase emissions are now regulated as exhaust emissions.
Fourth, the regulation requires engine manufacturers to monitor the performance of the engine's emissions system. This industry standard is called Engine Manufacturer Diagnostics (EMD) and will detect issues within the emissions control system.
Finally, the 2007 standard regulates the engines emissions system useful life, which has been set at 435,000 miles for heavy-duty and transit bus applications and 185,000 miles for mid-range applications.
The Caterpillar heavy duty solution for 2007 will use existing ACERT technology, which includes series turbochargers, variable valve control, a high-pressure multiple injection fuel system, Cat electronics control systems, and an oxidation catalyst. All 2007 Cat engines with ACERT Technology feature an enhanced combustion process called Clean Gas Induction (CGI), closed crankcase ventilation system, and diesel particulate filter system with active regeneration.
Mid-range engines also build on ACERT technology and feature a high-pressure injection system and the closed crankcase ventilation, with the addition of a variable turbine geometry turbocharger.
The Cat diesel particulate filter uses a wall-flow filter technology. Regeneration is necessary to activate a process of oxidation that eliminates the soot that collects along the inlet walls of the filter. To aid the regeneration process, the exhaust gas is heated by auxiliary means. Regeneration only takes place when needed, which optimizes fuel economy.
Engines with 500 horsepower or less will require one diesel particulate filter; engines with 550 or more horsepower will require dual filters. The filter system also provides sound attenuation and will be serviced by the Caterpillar dealer network and authorized truck dealers.
The primary process for achieving additional NOx reduction includes the elements of ACERT Technology with Clean Gas Induction (CGI). CGI draws clean inert gas from downstream of the particulate filter and then puts this clean gas into the intake air system.
A key advantage of CGI is the soot-free intake charge. In addition, CGI's low intake manifold gas temperature contributes to the engine's low NOx emissions. ACERT technology for 2007 delivers the same reliability, fuel economy, service intervals, and durability provided by current Caterpillar engines.
“We expect that our heavy duty engines with ACERT Technology for 2007 will maintain the same fuel economy as today's engines, and our mid-range products will improve by approximately four percent,” Gauger said.
Oil change intervals and sump capacity remain unchanged from today's ACERT Technology. By using Caterpillar's Clean Gas Induction technology, which employs soot-free inert gas as a NOx reduction building block, 2007 Cat engines with ACERT Technology will have the same durability as today's engines with ACERT Technology.
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