The Smoke is Clearing

Last month we took a look at the progress of each engine maker in meeting the accelerated Oct. 1, 2002, deadline for complying with diesel emissions limits set by the U.S. Environmental Protection Agency (“New Year Revolution,” April). We’ve since had more details, and I’ve driven a couple of near-production examples, both from Cummins. I liked ’em. In fact, Cummins was first off the block in this race, gaining EPA certification of its ’02 ISX engines in late March. It has shipped the first of them in recent weeks as part of the ramp-up plan. Mack is next, but all heavy-duty engine makers say they’ll have certified engines by October. All but one, it seems, will have a broad selection of engines that comply with the new nitrous-oxide (NOx) limits.

Caterpillar is the exception, the only one to reject cooled exhaust-gas recirculation (EGR) as the best technology to control NOx. It announced last year that it would drop EGR to pursue what it calls “ACERT,” or Advanced Combustion Emissions Reduction Technology. ACERT is a mix of new fuel-injection technology, electronics, and exhaust aftertreatment. But it couldn’t be ready in time, and at this point nobody will publicly say more than that about the specifics.

None of the new engine designs are as troublesome as was once feared, but they will likely cost you a few thousand dollars more. Prices are set by the truck makers, not the engine companies.

One more note before we review the engines: it’s possible to achieve EPA certification while also failing to achieve compliance with the new 2.5-grams-per-horsepower/hour NOx standard. Certification is not a seal of approval; rather, it simply defines the level of compliance and allows the engines to be legally sold.

Here’s how each manufacturer is progressing:

Come October, Caterpillar will sell so-called “bridge” engines. They won’t hit the NOx limit but will have EPA certification that spells out just how non-compliant they are. Fines will have to be paid by Cat itself, not by you — according to an EPA sliding scale where the minimum fine is in the $3000 US range per engine sold. Cat is lobbying to have the Oct. 1 deadline moved back. It won’t happen.

On the bridge engine, hardware changes will be minimal, except for the addition of oxidation catalyst aftertreatment. Cat still hasn’t defined ACERT engines publicly, but says its first such engines will arrive in the first half of next year. Claimed advantages include hardware simplicity, and the technology will be useable with the extremely harsh EPA demands coming in 2007, which can’t be said for EGR.

Cummins will have its certified and compliant ISX engine in full production by September, in ratings from 400 to 565 horsepower. By October it will be joined by certified and compliant ISM (up to 370 hp) and ISB engines, all three sporting a new electronic control module, an elegantly simple variable-geometry turbocharger made by Holset, a Cummins subsidiary, and the EGR cooler. ISM and ISX engines will be 110 and 130 pounds heavier respectively, and fuel economy will likely suffer by up to 3% or so depending on the application. The Signature 600 engine won’t be ready until 2003.

The ISX is the most tested of all ’02 engines, with well over four million test miles already. Its oil-drain interval is 25,000 miles, or 35,000 miles in light service. Warranty coverage will probably be the same at 250,000 miles.

Cummins has launched a Web site to explain the October 2002 emissions issue: www.tougheststandards.cummins.com.

Detroit Diesel is also using cooled EGR for ’02 engines, with a variable-geometry turbo, different injectors, and the same DDEC IV controls as now. The 12.7-litre engine will actually lose 50 pounds, and the 14-litre version will stay the same. Limited testing so far shows a 3.5% fuel-economy penalty. It’s worth noting that DDC has been producing heavy-duty cooled-EGR engines for transit buses since 1999, with some 2500 of them in service. They’re hoping to get to 30,000-mile oil drains.

Detroit will make about 95% of its current ratings available in October, certified and compliant.

Mack will introduce two EGR engines within its new “Application Specific Engine Technology” (ACET) family. One uses cooled EGR for highway use, while the other uses “internal” and un-cooled EGR in the vocational market. Both will be in ramp-up production by next month, certified and compliant by October.

The vocational “I-EGR” engine uses a new camshaft that re-opens the exhaust valve briefly after the combustion stroke to allow a precise amount of exhaust gas back into the cylinder to be burned in the next combustion cycle. There’s no cooler at all. Fuel economy suffers more than with a cooled approach, but that’s less important in the stop-and-go world of vocational engines, Mack reasons. The I-EGR engine will be available in the Granite series, plus the RD6, MR, LE, DM, and RB. The “C-EGR” highway engines rely on a cooler, a variable-geometry turbo, and modified electronics. Improved oil-filtering was added, along with a 25% bigger oil pan. Horsepower will cover 300 to 460, with three Maxidyne models and four Econodynes.

Mercedes is a dark horse for ’02, though it’s only available in Freightliners. The Mercedes-Benz MBE 4000 is a 12-litre in-line six, at 350 to 450 hp, that doesn’t have to meet the new standards until January 2004. That’s because it wasn’t available in 1998 when the EPA and the other engine makers clashed. It can be serviced at either Freightliner dealerships or Detroit Diesel locations.

The V-Pulse EGR technology from Volvo is similar to Mack’s I-EGR solution in that it uses naturally occurring engine pressure to re-introduce up to 30% of exhaust gases back into the cylinder. So except for VE D12 engines above 430 hp, the turbo stays the same (the high-horse engines get a new wastegated turbo). The design is thus mechanically simple. The cooling package doesn’t change, save for a new 11-blade fan, nor do oil capacity or weight. Volvo says durability won’t be an issue, though it admits there will be some small degradation in fuel economy. Oil drains are the same.

And that, briefly, is where we are on the hardware front. Questions remain about price (likely a few thousand dollars more) and warranty coverage, but none of the ’02 engines need huge changes to truck engine compartments as was once feared. Most truck makers have produced new or beefed-up cooling systems to handle the slightly higher heat rejection of an EGR engine, though that’s become a small issue. Oil drains seem likely to stay the same, and though test results show lower fuel efficiency (by 3% or so in every EGR case), development work continues.

Oddly enough, there’s a good side to all this, aside from your pleasure in doing the environment some good. If the Cummins ISX 500 I drove recently is any indication, you’ll love driving these engines. It’s all down to the gutsier variable turbo, I suppose, which delivers response like I’ve never seen before. Cummins says drivers in general react the same way to these engines, and Detroit Diesel also promises big gains in driveability. Depending on your wallet, that may be reason enough to buy an ’02. Eventually, you won’t have any choice.