TRUCK ENGINE EMISSIONS UPDATE: THE ROAD TO '07

AFTER SURVIVING CHANGES to diesel engine designs to meet tighter truck exhaust pollution requirements in 2002 and 2004, refuse fleets can be forgiven for grumbling about engine emission regulations taking effect in January 2007. To meet 2007 standards, industry estimates initially predicted aftertreatment devices could add up to $10,000 to the cost of a new truck. Fortunately, engine manufacturers say this is not true. Yet fleet managers are not completely off the hook. Fuel is likely to become more costly as the price per gallon increases and fuel economy decreases.

Understanding the Rules

Just to recap, on Oct. 1, 2002, the Washington, D.C.-based U.S. Environmental Protection Agency (EPA) required new heavy-duty diesel engines to emit no more than 0.1 grams per brake horsepower hour (g/bhp-hr) of particulate matter (PM), 2 g/bhp-hr oxides of nitrogen (NOx), and between 0.4 and 0.5 g/bhp-hr of non-methane hydrocarbons (NMHC). The NOx and NMHC measurements typically are combined for testing at 2.5 g/bhp-hr. In 2004, the rules were expanded to include medium- and light-duty diesel truck engines.

By 2007, emission level requirements for new diesel engines will become even stricter. PM emission levels decrease to 0.01 g/bhp-hr, NOx to 0.2 g/bhp-hr and NMHC to 0.14 g/bhp-hr. The PM requirement will be implemented fully in 2007, while the NOx and NMHC requirement will be phased-in between 2007 and 2010. As a result, new diesel engines in 2010 will produce less than 10 percent of the emissions of 2001 models.

To meet the 2007 rules, a few things are happening. Starting in June 2006, the sulfur content of diesel will drop to 15 parts per million (ppm) from the current 500 ppm. The EPA is requiring 80 percent of diesel fuel sold in 2006 to meet the 15 ppm standard, and increasing the requirement to 100 percent by 2010.

Back in 2002, most engine manufacturers believed that major aftertreatment devices would be required by 2007, adding significantly to the cost of a new heavy-duty truck. However, after two years of intensive work, engine makers believe far less aftertreatment will be needed.

“Using ultra-low-sulfur diesel [ULSD] fuel, we've found it is feasible to reduce in-cylinder emissions of NOx to a level that reduces the burden on aftertreatment in meeting the 2007 federal emissions standard,” says Patrick Charbonneau, vice president of regulatory and technology affairs for Warrenville, Ill.-based International Truck and Engine Corp.

He adds that the ULSD gives the industry more time to focus on the development of NOx aftertreatment systems for 2010, especially in terms of truck performance, cost effectiveness and durability.

John Wall, vice president and chief technical officer for Columbus, Ohio-based Cummins Engine Co. stresses that PM aftertreatment filters will be necessary for 2007 model year trucks to achieve the stringent emission standards. “Our experience with particulate filters and the availability of ULSD fuel combine to give us confidence in meeting these tough standards,” he says.

Allentown, Pa.-based Mack Trucks is adding a diesel particulate filter (DPF) system to reduce emissions in conjunction with its exhaust gas recirculation (EGR) engine platform to meet the 2007 rules. “EGR systems accomplish emissions reduction by returning a portion of exhaust gases back into the engine's combustion cycle. The recirculated exhaust reduces combustion temperature, which retards the formation of NOx in the engine's operations,” says Mack President and CEO Paul Vikner.

Mack expects to field test engines with EGR-based EPA 2007 technology with selected customers in 2005. “Everyone in this industry wants to avoid the confusion and market upheavals that accompanied the EPA 2002 emissions regulations,” Vikner says.

Jim Parker, vice president of Peoria, Ill.-based Caterpillar's power systems marketing division, notes that his company's Advanced Combustion Emission Reduction Technology (ACERT) systems for its truck engines will use new electronics and fuel management systems, combined with closed crankcase ventilation and a diesel particulate filter with active regeneration to meet the 2007 regulations. This should have less of a cost impact on truck owners than aftertreatment systems were predicted.

Low-Sulfur Impact

Despite the lower cost changes, switching to a 15 ppm-grade of diesel fuel will cause more problems for fleets. Not only is ULSD fuel more expensive — anywhere from 5 to 50 cents more per gallon according to early EPA estimates — contamination and reduced fuel economy also will be major issues.

“ULSD on-highway diesel fuel has a sulfur content of 15 ppm but will have to share the fuel distribution system with 500 ppm sulfur on-highway fuel and 5,000 ppm non-road diesel, as well as jet fuel and gasoline,” says Mike Ingham, manager of state fuels regulations, for San Ramon, Calif.-based Chevron-Texaco. “This is an issue the petroleum industry is very concerned about as we approach 2006. No matter how these products are sequenced through the distribution system, the potential exists for contamination to occur. Preventing such contamination will require the best efforts of everyone involved along the distribution chain,” he explains.

“Product integrity is our biggest challenge right now in terms of currently providing ULSD to transit and other fleets using this fuel,” says Stephen Levy, director of clean fuels for Portsmouth, N.H.-based Sprague Energy. “It's not about just delivering it from the refinery gate to the customer. [ULSD] has to go to storage, then gets transported through pipelines to a loading area for tanker trucks. You have to use dedicated trucks to transport it. You can't use that tanker to also transport gasoline, fuel oil or regular diesel.”

The industry predicts ULSD will cost more because of the investments required by refineries to make it. The EPA estimates the average investment for diesel desulfurization technology will cost $50 million per refinery, slightly more than the estimated $44 million per refinery required to meet the Tier 2 gasoline sulfur requirement.

“Most refiners will invest in the gasoline sulfur upgrade because gasoline is their major product,” according to the EPA. “Because U.S. refineries typically produce three to four times as much gasoline as highway diesel fuel, the per gallon investment cost of ULSD will be three to four times as high.”

In its “Regulatory Impact Analysis,” the EPA projects that the combined annual capital investment for gasoline and diesel desulfurization systems for the petroleum refining industry should top $2.15 billion this year and $2.49 billion in 2005. Other estimates, however, say refineries may end up investing anywhere from $3 billion to $13 billion to produce both low-sulfur diesel and gasoline fuels.

The composition of ULSD also will be an issue. Some experts believe it may end up providing slightly lower fuel economy than today's diesel fuel on a gallon-by-gallon comparison.

“The severe processing required to remove sulfur results in a fuel that has a lower energy content compared to the higher sulfur fuel,” says Chevron's Ingham. “Fleets could see a fuel economy penalty of 1 percent to 2 percent. Of course, original equipment manufacturers (OEMs) are working to improve the fuel economy of the next generation of engines. However, for fleets that have older equipment, in switching to ULSD they may notice a slight fuel economy penalty.”

The potential damage caused by misfueling a truck equipped with a 2007 engine could be more severe. Consequently, Ingham says the most straightforward way to transition to ULSD is to switch the entire fleet — old trucks and new — to the new fuel. “While ULSD is designed to enable the catalytic aftertreatment devices that will begin showing up on model year 2007 engines, it will provide benefits to every engine in terms of reduced particulate emissions and reduced acid load on the lubricating oil,” he says. “Handling only one fuel also will reduce the chances of misfueling an aftertreatment-equipped engine with higher sulfur fuel.”

Engines and Filters

The critical element for fleets is that diesel engines will only need particulate filters in 2007, says International's Charbonneau. That has been a great advance because the company originally thought it would have to rely on five key systems to meet the next round of emission rules: the fuel system, air management, combustion, electronics and aftertreatment.

“Now we'll be able to reduce NOx emissions in-cylinder without having to use aftertreatment technology, and then add only a particulate filter or trap to reduce particulate emissions down to where they need to be,” Charbonneau says. “The advancements in fuel systems allow us to use pilot injection for NOx reduction and sound quality improvements; higher injection pressure for improved NOx and particulate emissions; and post injection for soot cleanup.”

To manage the precise interaction of these diverse systems, much more computing power is going into 2007 products, Charbonneau says. “We are taking advantage of dramatically greater computing power that is cost-effective, allowing us to use more sophisticated control algorithms and even virtual sensors where the computer knows what the engine will do from an emissions standpoint without having to measure the actual emissions,” he says.

Finally, there will only be one additional piece of hardware in 2007 that International's — and most of the other engine OEMs' — fleets will need to manage: particulate filters.

“All of our 2007 diesel engines, whether for school buses, medium- or light-duty trucks, will use particulate filters,” Charbonneau says. “They are critical as they will eliminate more than 90 percent of the particulate and hydrocarbon emissions, leaving the exhaust smokeless and odorless.”

While particulate filters will need regular cleaning to remove the buildup of ash created from trapped particulates, he says this should not be too burdensome in terms of adding extra maintenance to trucks.

But how much more will 2007 engines cost compared to their current brethren? Charbonneau says the verdict is still out. “Pricing is still volatile — we're adding more EGR, more cooling, a particulate filter, ULSD fuel and new low ash engine oils,” he explains. “By eliminating the need for an aftertreatment system, the cost for the total engine may not be as high as some once predicted.”

Sean Kilcarr is senior editor for Waste Age's sister publication, Fleet Owner.

NEW OIL FOR 2007

As a result of the 2007 rules, the composition of engine oil is being altered to deal with the lower sulfur content of diesel and the presence of particulate filters.

Research on so-called “PC-10” oil for 2007 engines shows that the oil will have to handle a variety of conditions never seen before in diesel engines, says Gary Parsons, San Ramon, Calif.-based Chevron-Texaco's commercial automotive business unit manager.

“The big difference with PC-10 is that, up to now, our focus in developing oils has been entirely on how they perform in the engine,” he says. “Now we'll be concerned about how properties of the oil may affect emission control technology downstream of the engine. This is going to place new physical and chemical limits on oil.”

The real issue with PC-10 oils is that they will be costly to develop as well as to test. Parsons says the development costs for a new oil formulation average roughly $1 million and must pass 15 tests to meet the current CI-4 oil standard. For PC-10 oil, however, testing costs alone may rise to between $110,000 to $150,000 per test because of the new demands being placed on oil for 2007 engines.

“We're looking at trying to reach ash levels of about 1 percent and having a total base number (TBN) of about eight, compared to the 11 TBN standard we work with now,” he says. “That's going to change things significantly.”
— SK