COLUMBUS, Ind. High-mileage durability evaluations of its post 02 on-highway ISX engines indicate they are capable of providing the same or better durability than the power plants they replaced, according to Cummins officials.
The testing involved engines which had almost 600,000 miles (965,000 km) of commercial service.
"There is no difference in durability between pre ’02 engines and post ’02 ISX engines. The proof is in the parts," declared Bob Weimer, vice president, heavy duty quality.
Engine durability is typically defined as the point requiring an in-frame engine overhaul resulting from excessive component wear or oil consumption. Cummins engineers disassembled the evaluation engines and analyzed all major components from the crankshaft to the camshafts and from the EGR subsystem to the power cylinder.
Cummins said the engineering analysis confirmed both the integrity of oil control and combustion control with components exhibiting normal and expected wear. Power cylinder components showed only 20% to 25% wear after 600,000 miles, with connecting rod and main bearings expected to have 50% additional life remaining.
"Durability is not about carbon in the intake. An EGR engine is going to have carbon in the engine. That’s part of the design. It does not limit the life of the engine," said Weimer. He added that it’s soot that reduces engine life and the post ’02 EGR engines are proving to create less soot than their predecessors.
Weimer also said TBN analysis confirms cooled EGR engines are basically corrosion free.
Looking ahead to 2007, the next emissions standards deadline, Cummins officials reaffirmed their plans to meet the Environmental Protection Agency’s edict by integrating a particulate filter with cooled EGR. The Cummins particulate filter, developed and manufactured by Fleetguard Emissions Solutions, a Cummins subsidiary, is designed to reduce particulate matter emissions by 90% from current levels. It also replaces the existing vehicle muffler. The 2007 engines will also include a crankcase ventilation system from Fleetguard, claimed to eliminate any oil carryover from the engine. The trade-off in weight is about 75 pounds to the negative.
Service requirements for the filter can be extended as far out as 400,000 for line-haul operations, minimizing the operating cost impact to trucking companies.
Such in-house system integration provided Cummins with a distinct advantage in designing with 07 engines, according to Dr. John Wall, vice president and chief technical officer, eliminating the need to marry proprietary technology.
But one pressing challenge remains the uncertainty over the availability of ultra low sulphur diesel. "The most important aspect of the 2007 regulations is that a lot of what we have to do has to be done in an integrated way. Like any puzzle, you don’t have the whole picture if one piece is missing," said Christine Vujovich. "Ultra low sulfur diesel enables aftertreatment. If we don’t have 15 parts-per-million sulfur diesel the engine industry is in trouble because we have designed our engines based on that standard."
Cummins expects to have engines capable of meeting the ’07 emissions standards ready for field testing this August.
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