Ultra-clean Engines Enter Their Fifth Stage

Diesel engines capable of meeting Europe’s Stage V emissions regulations — a notch higher than the Tier 4 regulations currently in place in the U.S. — were unveiled en masse at the Bauma trade show in Munich, Germany this spring.

Indiana-based Cummins Inc., for example, unveiled four new “ultra-clean” engines that will meet the Stage V requirements when they go into effect in 2019.

“In the last Bauma, three years ago, we were talking about the Stage 4 products,” Jim Fier, Cummins vice-president of engineering, said at a press conference and unveiling at the company’s Bauma booth in April. “At that time, few if any of us anticipated that the next stage of standards would be upon us so soon.”

New rules limit particles

The new stringent Stage V standards, to take effect Jan. 1, 2019, would eliminate about 99.9 percent of particulate matter from diesel exhaust, something that requires a diesel particulate filter, noted a news release from Cummins.  A key requirement of Stage V, not in the previous stage, is a particulate “number count” that limits emissions to no more than a trillion particles for each kilowatt hour of engine output.

The maximum allowable weight of the particulates will also be reduced to 0.015 grams per kilowatt hour. Under Stage IV, the maximum allowed particulate weight is 0.025 grams per kilowatt hour, according to a posting on dieselnet.com that explains the European emissions standards in detail.

The European and U.S. Environmental Protection Agency standards, which each began phasing in during the mid 1990s, are harmonized to a large degree but with a different nomenclature — tiers for the U.S. and stages for Europe.

It’s not clear when or if the U.S. EPA will adopt a Tier 5 standard, according to recent articles in the trade press. However, if Bauma offered any indication it’s that engine manufacturers plan to be ready when the day comes.

Several makers ready or not

In addition to Cummins, other diesel engine makers had Stage V engines on display in Munich. They included Man Engines, which has been owned primarily by Volkswagen since 2011; Sweden-based Scania, of which Volkswagen is also the majority owner; Rolls-Royce, which showcased its MTU Stage V engines; Bavaria-based Hatz Diesel, and Osaka, Japan-based Yanmar.

Volvo Penta president Björn Ingemanson meanwhile told a Bauma press conference that the Swedish engine maker is about to begin its “Stage V approach,” which he said would be “a simple compact solution.” While he predicted that a Stage V engine would be four or five years away, he said Volvo’s solution would be similar to its on-road applications that meet the Euro 6 standard for commercial vehicles.

“So when we introduce (Stage V) we will of course have thousands of kilometres on road to prove the technology,” he said.

Scania Engines is already basing its Stage V industrial engines on its “successful Euro 6 engines for on-road applications,” a news release quoted Anders Liss, the vice-president of sales.

And it can offer those engines — in nine-, 13-, and 16-liter platforms ranging from 202 to 566 kilowatts — “well in advance” of the 2019 Stage V deadline, the release said.

Eliminating EGR saves space

The new Cummins Stage V engines are already compact and with a simple architecture, chairman and CEO Tom Linebarger said at the Cummins press conference. A key to that is the lack of an exhaust gas recirculation system, or EGR, and the presence of an after-treatment system “that’s 50 percent smaller and 30 percent lighter than its predecessor,” he said.

That trade-marked Single Module system can translate into an average of 10 percent more power and up to 30 percent greater torque in some cases, Fier said. The Single Module combines the DPF, selective catalytic reduction system, or SCR, doser, and mixer “into one unit,” Fier said.

“We have removed sensors and fault codes no longer needed,” Fier added. “And with an EGR-free design, we’re able to simplify the air-handling system, which only requires a single turbo. With all these initiatives, I’m very pleased to say our overall in-service reliability will rival that of engines meeting emissions three levels behind, taking us back to the reliability and service simplicity associated with our Stage IIIa, and Tier 3 engines — a remarkable achievement.”

Engines will also meet Tier 4

On top of meeting the stringent Stage V regulations, the new engines will be “co-certified” to meet the EPA’s Tier 4 final requirements as well as equivalent regulations in South Korea and Japan, a Cummins news release said. “That will make available the benefits of the EGR-free engines to help OEMs reduce the complexity involved with powering their global equipment platforms,” the release said.

The new Stage V Cummins models are the renamed F3.8, B4.5, B6.7 and L9, which range from 100 to 430 horsepower (75-321 kilowatts).

Cummins also renamed its heavy duty 12- and 15-liter engines, the X-12 and X-15, for Stage V applications, said a company news release. They “will retain the same DPF-SCR after-treatment system in order to provide ongoing installation continuity for OEMs in higher-output, more specialized machines,” the release said.

According to Cummins, the EGR-free X-12, which has a top rating of 512 horsepower, “lowers heat rejection by over 40 percent compared with that of engines using cooled EGR.”

Meanwhile, the 74-horsepower-rated four-cylinder F3.8 has engine-mounted DPF with no need for SCR, “making that rating particularly suitable for rental equipment,” a Cummins news release said.

The Stage V engines across Cummins’s 500- to 1,000-horsepower band also have a very high tolerance to sulfur in fuel, Fier said. That tolerance is 5,000 parts per million compared with 15 ppm for ultra-low sulfur specced engines.

“This tolerance removes a major barrier in reaching one of our goals of a universal engine platform,” Fier said. “OEMs will be able to use the same engine platform for every emissions need and standard, something that has eluded the industry for years.”

After-treatment system essential

Other manufacturers’ Stage V engines share many of the Cummins’ features, such as the requirement for a DPF, not needing an EGR, and employing an after-treatment system.

Yanmar said in a news release of its own that three new turbocharged and after-cooled engines it launched at Bauma are Stage V ready. In addition to enhanced fuel efficiency and compact size, the engines feature a “unique exhaust gas management technology” for the DPF that enables maintenance intervals of 6,000 hours — “effectively the lifetime of most machines,” the Yanmar release said.

Man Engines machines on display at Bauma — the 12-cylinder D2862 LE13x and the six-cylinder D3876 LE12x — can meet Stage V requirements when equipped with modular exhaust gas after-treatment, or AGN, a news release noted. Rolls Royce also had two of its new engines six-cylinder Series 100 and 1500 engines with AGN on display at Bauma. The engines “are currently being further developed jointly by MTU and Daimler, based on Daimler commercial vehicle engines, to meet EU Stage V regulations,” a release said. Rolls Royce expects the engine to be available in the 100- to 480-kilowatt range by the Stage V deadline in 2019.

“Construction companies will benefit immediately from the advanced technological developments for EU Stage V,” the release quoted Bernd Krüper, MTU’s head of construction and agriculture business. “What we expect to see from the development work are higher torque at low rpm, a further reduction in fuel consumption and an extended power range compared with predecessor engines.”

No modifications necessary

Hatz Diesel anticipates that its engines will meet Stage V standards “without any modification,” said a news release from the company, which is based in Ruhstorf, Bavaria about 65 miles northeast of Munich.

“In the power range 19 to 56 kilowatts, the new H-series fulfils the specifications of Tier 4 final,” the release said. “Thanks to the best preconditions for a proven exhaust after treatment, the step to a Stage-V-compliant engine is not far. Equipped with a diesel particulate filter it also ensures the requirements of EU Stage V in the future.”

The way Fier spoke, however, made it sound like Stage V actually prodded his company to build better engines.

“We have taken the opportunity to reinvent the engine and redefine their performance standards,” Fier said. “These engines will leap ahead of their Stage IV version by means of extra power, (and) extra torque without the need to increase displacement.”

Keith Norbury

Service Truck Magazine