The 2010 deadline for diesel engine makers to comply with tough new clean air regulations that call for virtual elimination of nitrogen oxide emissions is less than a year away.
For fire departments planning to specify new apparatus, the cost of compliance is uncertain. What is clear is that engine choices are going to be limited because some manufacturers have dropped out of the running.
Other than price, engine issues to be considered are maintenance, performance, fuel economy and space and weight.
Firefighters will have the choice of two methods used by engine manufacturers to meet the new limits – exhaust gas recirculation (EGR), which has been part of the automotive industry for decades, and a newer system, widely used in Europe, called Selective Catalytic Reduction (SCR).
Only one manufacturer, Navistar International, is using EGR technology, which, according to the company, takes up less room and is easier to use than SCR, which requires a storage tank to hold diesel emissions fluid (DEF) that is injected into the exhaust stream ahead of a special catalyst.
Navistar estimates its system will cost an additional $2,000 to $4,000 per engine, while the manufacturers using SCR technology say they haven’t settled on prices.
Because the new standard is so tough, Navistar and many other engine manufacturers are using emissions credits accumulated during recent years to help achieve compliance. Companies which made engines that exceeded past standards were allowed to bank credits for future use.
Detroit Diesel is believed to be the only engine manufacturer not using credits for compliance in 2010, but the availability of its engines for fire apparatus will be limited through an exclusive agreement with Pierce Manufacturing. Freightliner will use Detroit Diesel engines for its larger cabs and chassis.
Caterpillar and Mercedes Benz decided to stop producing engines for on-highway trucks as of 2010, leaving firefighters with fewer choices.
It appears fire departments specifying custom cabs and chassis other than Pierce will have only one choice – Cummins, which uses SCR technology.
Mack and Volvo vocational trucks used in fire apparatus will also use SCR, but both companies have tiny shares of the fire service market.
Bob Neitzel, Navistar International’s emergency vehicle marketing manager, said his company’s customers made it clear they prefer enhanced EGR over SCR technology because of EGR’s simplicity.
“We have customers that asked us to go beyond the SCR technology because of the issues with maintenance and training,” he said.
He described SCR systems as complicated and requiring maintenance because it uses urea or DEF injected into the exhaust for after-burn treatment.
The federal Environmental Protection Agency is requiring diesel powered vehicles to emit no more than .2 grams of mono-nitrogen oxides (NOx) per brake horsepower per hour by 2010. Brake horsepower is a measure of power produced by an engine at the wheel or driveshaft recorded by a dynamometer or similar braking device.
Navistar, according to Neitzel, achieved an emissions level using EGR technology of .5 grams NOx per brake horsepower per hour in 2007 when the standard allowed 1.2 grams NOx per brake horsepower per hour.
Banking Emissions Credits
“We banked a lot of emissions credits, and [EPA] lets you use them to meet the 2010 standard,” he said. None of Navistar’s engines will exceed .5 grams NOx emissions in 2010, he said, and the company continues to strive to hit the .2-gram target without credits.
Navistar International uses an improved EGR system, higher fuel injection pressures, converting diesel to almost a gas, as well as improved combustion technology to reduce NOx, Neitzel said. Twin turbos, computer upgrades and higher capacity cooling systems to handle the hotter engine temperatures are also incorporated to make the engines compliant, he said.
About the only change customers will notice on International’s complaint trucks will be a four-inch lift on its biggest cabs, Neitzel said.
The decision to go with EGR technology was easy, he said, because the company wanted to keep its engines clean to accommodate four-wheel drive and front engine ptos. The engine and emission design also permits a clean and accessible rear engine pto for other apparatus components, like pumps or generators, he said.
“We wanted to make our system as transparent as possible for our users,” he said. “In an emergency situation, when you have your hands full, you don’t need extra things to worry about.”
Neitzel described SCR as “a bridge technology” that will be temporary, leaving a generation of trucks “crippled” by a dated system. “There’s no question that SCR works,” he said. “It’s just not the choice our management wanted to take. It’s just too easy.”
Cummins Inc., an independent engine builder founded in 1919 in Columbus, Ind., will have SCR systems on all of its 2010 on-highway engines, including the mid-range and heavy-duty products, according to Christy Nycz, the company’s market communications manager.
Nycz said Cummins system uses SCR technology in addition to the EGR system it has had for years. The SCR system was developed by its partner company, Cummins Emission Solutions, which has been designing and building European systems for years.
Cummins’ cooled EGR with SCR emissions system was introduced in Europe in 2006 and has been used on 45,000 vehicles overseas with great success, Nycz said.
The biggest benefit the SCR system has over the EGR system, according to Nycz, is improved fuel economy. “We’ve invested in it,” she said. “There is no doubt it is the right technology for us, and we are completely confident in it.”
Cummins will introduce a new heavy-duty engine in 2010, called the ISX, retiring the popular ISM engine, she said. The ISX engine will be available in horsepower ratings up to 425.
Nycz said her company has encountered no objections to the SCR technology because users recognize its benefits – better fuel economy and high performance.
Cummins will use some accrued emissions credits, like Navistar, to be compliant with the 2010 standards. “We have been up front about that part of our product strategy,” she said. “And, in doing so, we will be fully compliant.”
Cummins has a partnership with PACAAR, the manufacturer of Kenworth and Peterbilt trucks, brands used in the fire service, Nycz said. The Cummins engines in those trucks are branded by PACAAR as the PX6, which is 6.7 liters, and the PX8, which is 8.3 liters.
Another Cummins partner is Daimler, the parent company of Freightliner and Western Star trucks. Cummins ISB and ISC engines will be used in Freightliner trucks under 50,000 pounds gross vehicle weight, according to Dave Siler, the director of marketing for Detroit Diesel, part of the Daimler corporation.
Smaller Freightliner trucks were previously equipped with Mercedes Benz engines, but he said Daimler decided “not to advance” the Mercedes MBE 900 engine, rated at 330 hp or less, to the next level of EPA emissions standards. Consequently, Cummins engines will be used in Freightliner trucks until at least 2012 to meet customers who require 330-hp engines or less.
Detroit Diesel Deal
Detroit Diesel engines of 350-hp or greater will be available in Freightliner trucks, according to Siler. “Ninety percent of Freightliner and Western Star trucks will be equipped with Detroit Diesel engines,” he said.
The exclusive deal between Detroit Diesel and Pierce Manufacturing and its parent company Oshkosh, according to Siler, was born out of a realization that sharing engineering resources would result in benefits for both companies. He described it as a “long-term engine supplier arrangement.”
Detroit Diesel introduced its first engine using SCR technology in 2005. Since then, the company has built more than 250,000 SCR engines for European vehicles.
The company, according to Siler, developed BlueTec, a proprietary emissions control system that optimizes EGR and SCR after-treatment technology for greater fuel economy and improved performance. “We started with a clean sheet and redesigned just about everything from the block up,” he said.
That decision resulted in engines that Detroit Diesel claims are the cleanest available, and Siler said the company is achieving compliance without emissions credits and without any loss of fuel economy or performance.
Because SCR is new to the United States, he said his company anticipates some resistance by firefighters.
“There is certainly a lack of understanding and a lack of experience with SCR,” he said. “And there’s a campaign to spread some fear or doubt about its feasibility.”
But, as customers learn more about SCR, Siler said he is confident they will recognize its advantages.
“In every case we’ve seen, SCR is the cleanest, most efficient technology available,” Siler said. “And with fire and emergency vehicles, that do a lot of idling and are often operating in urban areas, it’s important that they run as clean and efficiently as possible.”