New Generation Engines

Published in Western Canada Highway News, Spring 2008:
Engine manufacturers had to green up in 2007 as new U.S. Environmental Protection Agency emission standards came into effect. They rose to the challenge with innovative solutions in exhaust gas circulation and particulate filtering.

In December 2000, the EPA declared new emission standards for 2007 and later heavy-duty highway engines. The new limit for particulate matter (PM) emissions was set at 0.01 grams per brake horsepower per hour, one-tenth the standard that was in force in 1998 (which was about one-sixth the standard enforced in the late 1980s). Emission standards for nitrogen oxides (NOx) and non-methane hydrocarbons were similarly tightened. The PM standards were to take immediate effect in 2007 while the NOx and NMHC standards were to be phased in over three years.

The health effects of exposure to high levels of particulate matter can include decreased lung function and chronic bronchitis. Nitrogen oxides – compounds of nitrogen and oxygen, in varying complexity – are of concern due to their link to respiratory problems, acid rain, global warming and other troublesome issues. The EPA’s website says hydrocarbon emissions, resulting mainly from incomplete combustion and the evaporation of fuel, are “a serious air pollutant in cities across the United States.”

Cummins Inc. responded with confidence that it could comply with the new benchmarks and yet still deliver the quality its customers had come to expect. The company was “on schedule to deliver as promised, just as we did in 2002 (when new standards also came into effect),” Cummins vice-president Ed Pence said at the 2006 Diesel Techology Conference in Washington, D.C. “Given the breadth of our engine design capabilities, we consider emissions technology a competitive advantage for Cummins and we welcome the new EPA regulations."

For the big engine makers, the approach to meeting the new emission standards was essentially twofold: recirculating exhaust gas to cut emissions of NOx and NMHC, and filtering particulate matter so that less of it gets belched out. In Cummins’ case, it meant combining the newest version of the company’s cooled exhaust gas recirculation (EGR) system – already proven when Cummins met the 2002 regulations – with a particulate filter designed and produced by Cummins division Emission Solutions.

“We have delivered on our promise to have certified compliant engines that perform and deliver on the things that are most important in the trucking industry, which are performance, fuel economy and reliability,” Cummins spokesperson Louis Wenzler said this year. “And as we step back and listen to customers and fleet owners that we talk to on a regular basis, our interpretation would be as they grade our scorecard that (they believe) Cummins has delivered on its promise. The product is working.”

Wenzler said Cummins was pleased to see that the engines “worked as designed” right from the start, though “minor adjustments in the software” were made after the first units hit the market. He emphasized the word minor. “Have we made design changes that drive hardware changes and assembly changes? The answer to that is ‘No.’ The fundamental product as released is stable, is remaining with no changes. Have we made minor software changes? Yeah.”

Caterpillar Inc. responded to the emission-reduction challenge with refinements to its trademarked ACERT technology. To the basics of ACERT – air management, precision combustion, etc. – the company added clean gas induction (CGI) to reduce NOx levels, as well as a top-notch diesel particulate filter. CGI is an ACERT process that cools filtered non-combustible gas and and then blends it with more incoming cool, clean air before returning it to the combustion chamber. A company brochure emphasizes that these engines differ from competitors’ products in that they put clean air into the combustion chamber – “not the recycled exhaust gas of cooled-EGR technology.”

A news release from Caterpillar last fall said the new engines “provide the value, performance and fuel economy customers expect.” Lorne Lagimodiere, truck engine account manager for Toromont Cat in Winnipeg, concurred with that assessment early this year. He added that the 2007 engines provide better response, power and fuel economy. And the trucks running on those engines invariably have clean smokestacks as testament to how well PM pollution has been cut.

Truck sales volumes shot up in 2006 “because truckers knew that that the ’07 engines would cost anywhere from $8,000 to $13,000 more,” said International Truck and Engine’s Roy Wiley. “There was a big pre-buy in 2006. For the medium-duty engines the price difference was a lot less – more like $4,000 to $6,000. But for the big-bore engines - well, those engines are quite expensive.”

The Pro-Star Class 8 truck was at the centre of International’s response to the 2007 standards. The MaxxForce 11 and MaxxForce 13 engines in those trucks included proven cooled-EGR systems and advanced aftertreatment systems. A company vice-president pledged in 2006 that the new engines would deliver outstanding performance and reliability along with improved air quality.

"The new engines are being received well in the marketplace," Wiley said months after the launch. He added that the engine systems were subjected to “your normal tweaks that you sometimes have to do, but nothing out of the ordinary.”

Mack Trucks also used a combination of cooled-EGR technology and a diesel particulate filter to cut emissions from its MP engine series down to 2007 standards. Early reviews from customers were rather positive. The GM of a Pennsylvania industry supplier, for instance, said in late 2006 that his company tested the new Macks and “had absolutely no issues. I would not hesitate to buy more of these trucks.”

“We’re very happy with the product,” Murray Marshall, general manager of Mack Sales and Service in Winnipeg, said early this year. “Our customers are very happy as well.”

His shop has sold well over 100 of the new engines, so they’ve got a good idea of how well the engineering panned out. And it was all aces, he said, with the engines being “great right out of the box. … The guys did a great job engineering these parts into the engine. … It went off really well.

Feedback from customers was extremely positive, Marshall said. “The most common comment that we received back was how quiet and powerful these new engines were.”

Volvo Trucks North America president Peter Karlsten said in 2006 that its new D11, 13 and D16 engines “will make our air cleaner and help our customers be more productive and efficient.” The new engines were to use high-efficiency cooled EGR and a diesel particulate filter to tackle the emission challenges.

So, now that the new products are out and in use, what’s the prognosis? “Other than the expense, they were very well received,” Winnipeg Beaver Truck Centre fleet manager John Oades said. Extra cost and weight were issues, he added, and Volvo made very minor tweaks to enhance their products after after they hit the market.

Detroit Diesel’s heavy-duty Series 60, perhaps the most popular on-highway diesel engine in North America, came equipped in 2007 with an aftertreatment system for removing PM from the exhaust, and a top-drawer EGR system to meet the NOx emission targets. The company took other measures as well to improve the performance and cleanliness of the engine.

Detroit Diesel spokesperson Dave Siler said the company’s ’07-compliant engines – which also included the revamped MBE 4000 – got a “lukewarm” reception on the market at first, largely due to typical caution toward new products. In the end, however, the engines were embraced as the sort of top-quality products truckers have come to expect from the Michigan-based company.

Detroit Diesel has seen “better-than-expected particulate regeneration” in the new engines, he added.

The next challenge for heavy-duty engine manufacturers is to meet even more stringent NOx emission limits by 2010. Cummins announced last September it will rise to the challenge with engines that include the company’s own “next-generation cooled EGR,” without adversely affecting fuel economy, power and torque. It has already met 2010 NOx standards with the engines for certain Dodge pickup trucks.