‘Near-Zero NOx’ Natural Gas Engine From Cummins Westport Is On The Way

April 11, 2016 by John O'Dell

A commercial truck and bus engine that brings clean emissions to a whole new level is about to debut, seven years in advance of the low-emissions regulations it is designed to meet.

Natural gas engine developer Cummins Westport Inc. told Trucks.com that its 8.9-liter “near-zero NOx” engine, previously scheduled for launch at the end of the year, is finishing its field test phase and the company will start taking orders this month. Cummins Westport is a joint venture of diesel engine giant Cummins Inc. and natural gas engine developer Westport.

The engine slashes emissions of nitrogen oxide, or NOx, a smog- and ozone-causing product of fuel combustion that is particularly difficult to eradicate. Its emissions are equivalent to that of a bus or truck “powered by electricity from a modern natural-gas-fueled power plant,” said Jim Arthurs, Westport’s executive vice president and chairman of the Cummins Westport venture.

Put another way, converting all 2,200 transit buses in a city the size of Los Angeles to the new engine would result “in the total NOx emissions from the entire fleet being the equivalent of what was emitted by just two buses in 1985,” he said

The Cummins Westport natural gas engine — called the ISL G NZ (near zero) — is aimed at helping trucking companies meet regulations set by the federal Environmental Protection Agency clean-air standard that phases in from 2023 through 2031.

Both the EPA and the California Air Resources Board have certified the engine at just 0.02 grams of nitrogen oxide per horsepower-hour. The standard is not mandatory now, but the board is proposing to make it a requirement throughout California as part of an upcoming statewide air quality plan that, like the federal standards, would phase in through 2031.

The new engine emits 90 percent fewer NOx emissions than the present standard of 0.2 grams per horsepower-hour and “represents a significant step forward in near-zero emissions technology for the heavy-duty vehicle sector,” said Barry Wallerstein, former executive officer of the South Coast Air Quality Management District.

The agency manages clean-air regulation and policy in most of Southern California and has been an active backer of the near-zero engine development process, with Wallerstein and his staff managing the contracts and helping to organize the development team. (Wallerstein headed the South Coast Air Quality Management District until he was removed from his post by a new business-oriented board majority earlier this year.)

NOx is difficult to reduce, especially out of diesel emissions.

Just ask the emissions engineers at Volkswagen, which resorted to cheating to get NOx levels for it diesel-powered passenger vehicles low enough to meet U.S. regulations. The company, as a result, is facing plummeting sales and potentially billions of dollars in expenses, including federal and state fines, to bring the cars into compliance and make restitution.

It wasn’t gaps in technology that caused the VW emissions scandal, though. The company just didn’t want to deal with the extra extra cost of building diesel engines with sufficient emission filtration to do the job.

Natural gas is naturally lower in NOx than diesel, and the engineering team that developed the Cummins Westport engine used that as a starting point in its effort to remove even more of the stuff from the engine’s emissions stream.

Arthurs said that a bus outfitted with the new engine would likely cost 10 percent to 15 percent more than an equivalently equipped diesel bus. In California, some help is on the way: The Air Resources Board recently added $2 million to its HVIP hybrid and electric truck and bus voucher program for low-NOx engine purchase incentives, and is seeking to boost that to $23 million for the 2016-17 fiscal year.

The engine also is more expensive than a standard natural gas engine, “but not significantly so,” he said.

The new engine’s size and power output mean it will also work in refuse trucks and medium-duty work trucks.

Wallerstein, the former South Coast Air Quality Management District director, said the agency plans to help fund ongoing work by Cummins Westport, which is working on larger “near-zero” engines for heavier applications.

“We absolutely need this technology to achieve our clean-air goals in Southern California,” he said.

Indeed, the air management district’s board voted on March 4 to petition the EPA to apply California’s low NOx emissions target as a national standard. The California Air Resources Board has submitted a similar petition.

Much of the funding for the initial phase of the near-zero natural gas engine project came from the South Coast Air Quality Management District ($2 million) and two other California organizations: Southern California Gas Co. ($1 million) and the California Energy Commission ($4 million).

Exactly how the engine achieves its ultra-low NOx emissions without expensive after-treatment such as the ammonia injection (selective catalytic reduction) systems used with diesel engines is proprietary information that Cummins Westport won’t disclose, Arthurs said.

But it involves limiting the amount of oxygen introduced into each cylinder to burn the fuel, reaching the ideal balance, called stoichiometric combustion, he said.

Arthurs said he expects that California initially will be the principal market for the new near-zero NOx engine as it has the nation’s most stringent emissions standards.

But 11 other states (Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington) have adopted other California emissions standards and would likely be early markets if they adopted an ultra-low NOx standard.

If the Air Resources Board and South Coast Air Quality Management District petitions from California eventually sway the EPA, that would open up a nationwide market for the new engine.

Editor’s note: this article has been updated to clarify how NOx is reduced in the Cummins powertrain. Additionally Jim Arthurs, Westport’s executive vice president and chairman of the Cummins Westport venture, was referred to as John Arthurs.

This article was prepared by Trucks.com but appeared first on Forbes.com as part of a content distribution agreement.

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One Response

  1. Rev. Jim

    This amazing engine is going to be (already is) a milestone in the new era of clean fueling for trucks and buses. I just wonder as we become energy independent, OPEC free, & Keystone reliant, which will be a more affordable fuel, clean lng – cng or petrol?


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