Pollution and politics go together like pork and beans, especially in Washington,
DC. Controversy has surrounded the U.S. Environmental Protection Agency since
its birth in 1970 and its first victory, which was to ban lead in gasoline and
require catalytic converters in cars. It's been winning on the diesel front
too, but the tough emissions standards it has ordered for 2007 are still the
source of much second-guessing. And then there's 2010.
The coming EPA standards - mirrored here in Canada - really are tough. In 2007,
half of all on-highway diesels sold will be allowed to emit no more than 0.20
g/hp-hr (grams per horsepower-hour) of nitrogen oxide (NOx), which is a whopping
90% drop from 2002/04 levels. By 2010, 100% of on-highway engines must be at
the 0.20 mark. On top of those reductions, '07 particulate emissions can't exceed
0.01 g/hp-hr, also a stunning 90% drop, a standard that will remain in place
for 2010. The challenge is enormous.
And what will you see in January, 2007?
All engines except the Mercedes diesels found in some Freightliner, Sterling,
and Western Star trucks will follow the basic technology paths that met the
2004 standards. Cummins, Detroit Diesel, Mack and Volvo will continue with cooled-exhaust-gas
recirculation (EGR), while Caterpillar will continue using its ACERT technology.
All will add a diesel particulate filter, including Cat, which is already using
an oxidation catalyst behind its engines. Mercedes engines will use both EGR
and a particulate filter. None of them will use selective catalytic reduction
(SCR) technology (see sidebar).
All of these 2007 engines will be running on ultra-low-sulphur diesel fuel
(ULSD), which the EPA has mandated for mid-2006. It's a radical reduction of
the sulphur content in fuel from 500 to just 15 parts per million. Because it
will require different and additional refining methods, transportation means,
and storage facilities, it will cost more, though how much more remains to be
seen. U.S. estimates suggest up to five cents per gallon. Older diesels will
run fine on the new fuel.
And yet again, '07 diesels will require another new lube-oil spec just as present
models did.
That much we know, more or less, but the fighting really doesn't seem to be
over. Even the General Accounting Office, the non-partisan investigative arm
of the U.S. Congress, called for an independent examination of the '07 rules
in a report issued in mid-March (see www.gao.gov).
"We think there are sufficient technological challenges to justify a second
independent review," said John Stephenson of the GAO in a presentation
to delegates at the annual meeting of the Technology & Maintenance Council
in Fort Lauderdale, Fla., on March 16. Taking part in a full day of panel sessions,
called the Diesel Engines Emissions Summit II (another was held last fall),
he said several technological issues were missed in a previous review. Among
them, he said, is the distribution of ULSD fuel.
He wants incentives for truck buyers, in hopes of preventing the massive pre-buy
of trucks with old-style engines that occurred in advance of October, 2002 when
the '04 standards went into effect. The American Trucking Associations is also
looking for tax credits to encourage truck buyers to accept '07 engines.
At the lively first session of the TMC summit, populist Republican Congressman
Mac Collins from Georgia was hard on the EPA and its ham-fisted handling of
the 2002/04 emissions rules. A truck fleet owner himself, he said he doesn't
buy the EPA's stated commitment to make all this work.
He said the consumer's pocketbook must be considered in the course of protecting
the environment. He added that we don't know enough about the economic impact
of the pull-forward of 2004 rules to October, 2002, and he guessed that it was
much more than anyone imagines.
"The truth of the matter is that I don't trust the EPA, and I caution
you to be careful," he told the 1100 Summit delegates in closing. "We
should never have a government that we can't trust."
The New Engines
Some time next year engines meeting the 2007 emissions standards will be on
the road in real-world tests, operated by fleets in revenue service. All diesel
makers say they'll meet this goal, and oil refiners say they can supply enough
ULSD fuel to facilitate the testing. They'll establish "corridors"
in the U.S., routes along which the fuel will be available in advance of 2006.
It's not clear if similar corridors will be set up in Canada.
The test engines will be pre-production models, giving the industry a chance
to work out the inevitable bugs over the course of 18 months or so. That will
be a welcome change from October of 2002, when engine makers and fleets alike
complained of too little development and testing time.
Here's what you can expect:
Caterpillar's ACERT solution, which presently employs a mix of injection, combustion,
and electronic tools along with exhaust aftertreatment, will continue on that
path. Cat's John Campbell told Summit delegates that the 2007 ACERT engine will
employ a "next generation" fuel system, advanced combustion technology,
better thermal management, and a particulate filter. Cat's aiming at a 150,000-mile
interval for filter maintenance. There may also be a secondary filter required,
he said.
Selective catalytic reduction (SCR) was once thought to
be part of the 2007 emissions solution in North America, but its chief
proponents, Detroit Diesel and Volvo, recently announced they'll go
with EGR after all. SCR is the choice for Europe's next round of emissions
rules ('Euro 4') coming in October, 2005. They're roughly equivalent
to the 2007 North American standards.
SCR is a well developed technology that reduces NOx while
returning better fuel consumption than EGR. It uses ammonia produced on
board the vehicle from a non-toxic liquid urea solution in a separate
tank. The urea solution is added to a catalytic converter to make the
required ammonia. Urea is a colorless, odorless liquid widely used in
many industries.
The downside of SCR is that it demands a supply network
for the urea, with special pumps for filling urea tanks at truckstops
and fleet yards. That didn't endear it to the EPA, which has also expressed
concern about enforcement issues - how could it ensure that urea tanks
were always filled?
But don't count SCR out for 2010. Most engine makers have
extensive experience with it, and Cummins says it's already using it in
some off-highway applications. Detroit Diesel calls it "a viable
alternative for 2010." Cat's investigating it but it's at "the
bottom of our list," according to on-highway engine chief John Campbell.
At Cummins, said Dr. Steve Charlton, '07 engines will look exactly like their
'02 brethren, though they'll need an 'active' particulate filter.
A 'passive' filter takes advantage of normal exhaust heat to 'regenerate' itself
periodically, meaning it oxidizes or burns accumulated soot and cleans itself
with the help of a catalyst. An 'active' filter creates additional heat when
needed by electric means or by an injection of fuel, managed by engine software.
Passive filters are generally ineffective at low loads and low ambient temperatures.
PM filter technology has been under development at Cummins since the 1980s.
The company is working with lube-oil additive suppliers to come up with low-ash
compounds with the target of maintenance-free filters by the time we get to
2007.
Charlton said a particulate filter will not be irreparably harmed if fed high-sulphur
fuel. It will get dirty faster, and the truck will probably not meet emissions
standards for a time, but the filter will eventually clean itself out.
Cummins is now working on packaging and integration issues with truck makers.
It has prototype engines running in trucks today and will have 20-30 development
engines in customers hands by mid-2005.
Detroit Diesel's Tim Tindall said the company is still running parallel development
programs with both EGR and SCR technologies, having chosen the former for North
America, the latter for Europe. Developments of the '02 Series 60 technology
now in use include changes to the fuel system and to the troublesome EGR valve,
advanced electronics, additional sensors, and a closed crankcase ventilation
system as well as an active particulate filter.
The filter's design is not finalized, Tindall said. Engineers are still working
on its regeneration method and its physical shape. He added that heat rejection
remains an issue, saying an '07 engine may run a little hotter and could conceivably
require a larger radiator.
A new 14.8-litre engine being developed by DDC and parent company DaimlerChrysler,
scheduled for release in 2007, will also employ EGR and diesel particulate filters
for North American applications.
At Mack and Volvo a common base engine (a variation on the present Volvo 12-litre
model, though a larger block may be coming) will find its way into both chassis
brands, marking the end of the Mack E7, and will feature cooled EGR with active
particulate filtration.
Volvo's Tony Greszler told the packed TMC auditorium that the company's target
is to offer a filter that needs no service until 300,000 miles, double what
most others were estimating. That service cost should be about $150, he said.
He anticipates no reduction in other service intervals, and said they might
even be extended. The company plans to have about 30 engines in field testing
by next spring.
Four men in charge of trucks at four of the biggest U.S. fleets expressed
universal displeasure with '02 diesels in a panel session during the Engine
Emissions Summit at TMC. Fuel-economy losses reported were as high as
15%, as low as 3%.
Dennis Beal controls 9130 tractors doing LTL work at FedEx Freight. He
told delegates that his 758 '02 engines have run a combined 29 million
miles, the highest single mileage figure being 175,000.
"We've had no horror stories," he said, "but we've had
a lot of pain and the costs have been horrendous... We still believe there's
a big improvement that can be made."
He's been surprised by the relationship between horsepower and fuel efficiency.
"Everything I thought I knew about horsepower, I've had to throw
out the window," he said. At FedEx, the higher the horsepower rating
of an '02 engine, the better the fuel economy has been.
Beal added that there have been relatively minor reliability issues,
and on the positive side, routine oil and coolant analyses have shown
no problems. He's been able to maintain his 36,000-mile service intervals.
Steve Duley, vice president of purchasing at Schneider National, said
oil-drain intervals have gone unchanged on his fleet's 1000 '02 engines
(a mix of Caterpillar, Cummins, and Detroit) as well. He also said that
there have been significant improvements in the engines he's buying now
compared to the first batch of '02 motors, proving that the regulatory
pull-ahead from January 2004 to October of 2002 was very costly.
Fuel-economy losses at Schneider have been in the 3-5% range, though
parts costs have doubled, and overall the incremental price of these engines
works out to 2-3 cents per mile.
Marty Fletcher, director of technology at U.S. Xpress, has some 1200
'02 motors, also a mix of Caterpillar, Cummins and Detroit. They have
collectively suffered a fuel-economy degradation of 9-12% based on engine
ECM data.
Jim Salas, manager of application engineering at Ryder Transportation
Services, the final speaker on this panel, said he's charted a four-cent-per-mile
operating cost increase. Among his main concerns is the growing lack of
choice in engine/chassis combinations, given various alliances and the
onset of vertical integration at some truck OEMs.
Having also developed SCR engines for Europe (until recently it was thought
Volvo would use them here too), Volvo says that technology remains promising
for future applications in North America.
Clearly, the key to the success - and much of the extra cost - of all 2007
engines will be the particulate filters they employ. Steve Duley, vice president
of purchasing at Schneider National, says he's concerned about the cost of these
particulate filters, saying they look simple but aren't likely to be as simple
to own.
They will add some weight, about 140-170 lb for heavy-duty engines, says Pedro
Ferro, vice president and general manager of ArvinMeritor's Commercial Vehicle
Exhaust division.
His company, better known for axles and brakes and such, is in fact a leader
in the exhaust filtration field, including SCR, and its Thermal Regenerator
is an active particulate filter that boasts 99% filtration efficiency without
using expensive precious metals on the filter media. The system identifies when
regeneration is required, then injects a small amount of fuel into the exhaust
stream to reach soot-burning temperature in seconds. The regeneration takes
about 10 minutes and would typically be required every 100 hours, consuming
a half-litre of diesel fuel.
Ferro looks ahead to 2010 and, as most engine makers are speculating, sees
the need for additional hardware to control NOx in the exhaust stream, not in
the cylinder. SCR can achieve that, but EGR probably can't do it on its own.
But the more immediate questions concern 2007 and especially the likelihood
of another round of pre-buying. There's no doubt that these engines will be
more expensive, though cost estimates are impossible to come by. Same with fuel
economy: it's up in the air, though it probably won't change too much. And as
for how an '07 diesel will fell under your right foot, nobody knows that either.