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Straight talk on emissions

EDMONTON, Alta. - Engine manufacturers were at the Alberta Fleet Maintenance Supervisors Association's (AFMSA's) maintenance conference to discuss 2002 engine performance and the impending '07 and 2010 emissions standards.


EDMONTON, Alta. – Engine manufacturers were at the Alberta Fleet Maintenance Supervisors Association’s (AFMSA’s) maintenance conference to discuss 2002 engine performance and the impending ’07 and 2010 emissions standards.

In a panel discussion on what has become one of the most talked about topics in trucking, Robin Ross of Volvo Trucks explained why the 2002 low-emission engines have experienced fuel economy degradation. It’s a subject that’s been danced around many times before, but Ross explained there are valid reasons for the loss in fuel mileage.

“The heat rejection on all of the new engines is substantially higher than the pre-EGR engines,” said Ross. “A lot of the energy that’s in that bucket of fuel gets dispersed as heat and the problem that arises is how do you disperse the heat?”

One way is through use of the engine fans, which in many cases are now bigger, with more blades and an increased pitch compared to older fans.

“The fan itself is eating up more horsepower than it did on the pre-EGR engines,” Ross explained.

Use of electric fans may restore some of that fuel economy degradation in the future but it’s not yet a viable option as the large fans would require more than a 12-volt battery to power them, he said.

That alone would restore 40-50 hp, Ross predicted.

Also, other accessories may be driven off the flywheel in the future rather than being powered by fuel.

Another factor contributing to the widely reported fuel mileage losses is driver-related. The fuel economy band on the new engines is narrower than on previous engines and the punishment for straying outside that magic RPM band is more severe.

“Drivers need to operate in the green,” Ross said.

Despite the fuel economy degradation, the EGR engines are performing well, said Mal Shephard, Detroit Diesel’s sales manager for Western Canada. His company currently has 40,000 Series 60 EGR engines on the road with more than 2.5 billion miles accumulated.

However, he admitted the company is constantly tailoring its EGR system to address problems that have arisen.

For instance, Detroit Diesel has introduced a new exhaust system to better control any exhaust leaks that can occur. The manufacturer has also adopted a new injector – the Bosch N3.

New electronic controls have also been introduced which feature more memory and more output pins.

Shephard explained Detroit Diesel’s sister company, Mercedes-Benz has taken a different approach to meeting the 2004 emission standards. While Detroit Diesel utilizes a variable geometry turbocharger, the MBE 900 and 4000 instead use a re-valve system.

“One is not necessarily better than the other, it’s a characteristic of the engine design which is more suitable,” Shephard explained.

Zack Ellison of Cummins said his company explored all possible alternatives to EGR before settling on the most popular technology.

“We didn’t just go to EGR and say ‘That’s it,'” he said. “We can actually (meet the ’04 standards) in-cylinder if we want to.” But that would result in further fuel economy degradation, he hastened to add.

Cory Just of International Truck and Engine Corp. said the I-6 medium-duty lineup also features EGR in order to meet current emission standards.

The lone company to opt for something different was Caterpillar, with its introduction of ACERT engines.

“The long-term beauty of ACERT is that the technology we are currently using today will be the same solution for 2007,” said Jason Nelson of Caterpillar. He said Cat spent $40 million on research and development that included a full-fledged EGR program but “We basically cut the umbilical chord and dropped the program. We tried it – we’ve been there and we decided to not go down that road.”

ACERT engines use existing, proven components, he explained.

But while Nelson said the beauty of ACERT is that it will be able to meet 2007 standards, the other manufacturers are quick to point out the same can be said of EGR.

Engine makers who’ve adopted EGR all have plans to further develop the technology to meet the ’07 standards.

“We can get there very easily (with cooled EGR),” said Cummins’ Ellison. “It’s not nearly as major a change as when we went to EGR.”

A bigger exhaust gas cooler will be required in ’07 and there is hope that some of the fuel economy losses faced with the current lineup will be recouped, he said, adding the only change customers can expect in ’07 is the addition of a diesel particulate filter – a trap that each manufacturer will be employing which captures particulate matter and burns it off. (Customers can also expect a price increase, which Ellison told Truck News should be in the ballpark of CAD$4,000 (or US$3,000.)

Ellison was quick to point out, however, the engine itself won’t be much more expensive – the increased cost can be chalked up to the particulate filter, modifications to the truck chassis to accommodate the increased cooling capacity and larger radiators which will likely be required. Shephard estimated that if Freightliner had to go to production today to meet the ’07 standards it would require a 1,500 square inch rad to handle the extra heat buildup under the hood.

Nobody on the panel was a huge fan of Selective Catalytic Reduction (SCR), even Volvo’s Ross.

“There are some pretty horrendous problems with (SCR), particularly on the logistics side,” he admitted. For instance, setting up a urea distribution network would be an enormous undertaking.

Cummins’ Ellison was also critical of the technology.

“Cummins doesn’t see the EPA letting us do SCR because it’s too easy to just stop putting the (urea) in there,” he said, adding Cummins has concluded that EGR will add an extra cost to the end-user of CAD$416 (US$300) per year whereas SCR will provide additional costs of nearly CAD$2,000 per year (US$1,400 ) for the truck owner.

“SCR is not very appealing for 2007 to us,” he said.

Volvo’s Ross said truck owners can expect a wide array of new engines in the coming decade, and pointed out engines with no camshafts are being tested.

“There’s going to be some fairly substantial changes in product between now and (2010),” he said.


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