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products Engines/Drivetrains

Power Trippin’

Posted: August 1, 2014 by Rolf Lockwood

Assuming you’re able and willing to buy a truck or three next year, the decision may be a bit more difficult than usual. Or at least you may think so if you listen to the rhetoric that fills trucking’s airwaves these days. It’s all about approaches to the 2010 diesel emissions mandate.

In an era when it seems impossible to buy a bad truck — they’re all that good these days — we haven’t really been able to say the same about emissions technologies since 2002. Some have clearly worked better than others. And some have cost you more than others mile by mile. All have cost you thousands to buy.

In 2010 you’ll face a similar dilemma, but with a twist. As if anyone needed this covered yet again, one engine maker will continue with a solution we’ve come to understand, if not love, while all the others will introduce a new one.

It’s International Trucks against the world. It’s advanced exhaust gas recirculation, or EGR, against a milder form of EGR with the addition of selective catalytic reduction, or SCR. In-cylinder control of nitrogen oxides vs. NOx reduction by aftertreatment.

Aside from all the rhetoric, which we’ll avoid here, there’s also some new iron to talk about. All the engine makers except Kenworth and Peterbilt had their 2010 wares on display at Mid-America. Most of these introductions were very low-key, some without formal announcement at all, but Navistar went big. It launched the MaxxForce 15 with smoke, mirrors, and considerable fanfare.

The MaxxForce15 will indeed be a modified version of today’s Caterpillar C-15 without ACERT, built under licence at the Navistar engine plant in Huntsville, Alabama starting some time in 2011.

Essentially, International will be meshing Cat  iron with its own air and fuel management hardware and software. That will include a variation on MAN’s high-pressure common-rail fuel ­system, as used on the MaxxForce 11 and 13, but with higher ­pressures. Twin turbos in series will be employed. We’ll see ratings from 435 to 550 hp with torque output from 1550 to 1850 lb ft, including two multi-torque models.

The fuel system introduces fuel into the cylinders at very high pressure at low engine speeds and in several metered or staged sequences within each combustion cycle. Conventional systems don’t achieve peak pressure at these low engine speeds where fuel economy is inherently better, says International.

The system can deliver peak fuel pressure of up to 31,800 psi at any engine speed. This results is very efficient combustion with peak torque achieved at 1,000 rpm (just above idle). This allows for earlier upshifts when accelerating and fewer downshifts when climbing hills. Operating the engine at low speeds also minimizes engine friction for better fuel efficiency, says International.

A not so painted design of the MaxxForce 15,
which is more or less a Cat C15

The Cummins ISX15 has a new little brother, the ISX11.9. The latter is not the Chinese engine that some have presumed, though it was derived in part from the development of a Cummins 13-liter diesel to be built in China for the Chinese market. The ISX11.9 will be manufactured in the company’s plant in Jamestown, NY. Its 15-liter mate still offers as much as 2,050 lb ft of torque in 2010 trim, and a brief look at its various power and fuel maps shows an incredibly wide sweet spot.

Claiming improved fuel economy, performance, and reliability compared to today’s model, the new ISX15 features the Cummins XPI fuel system, an enhanced cooled-EGR system, and a single variable-geometry turbocharger. The new Cummins aftertreatment system uses selective catalytic reduction (SCR) catalyst technology together with the in-house-made particulate filter that was introduced in 2007.

The XPI fuel system, co-developed with Sweden’s Scania, mates with a single overhead camshaft, whereas the ’07-spec ISX had two overhead cams. Ratings will be maintained from 400 to 600 hp, with torque outputs from 1,450 to 2,050 lb ft.

Cummins claims an industry-leading power-to-weight ratio among big-bore engines. It also claims fuel economy gains of up to five percent compared to its own 2007 engines, and as much as a nine-percent advantage over International’s 2010 EGR engines.

The new ISX11.9 is a compact and lightweight medium-bore engine aimed at vocational trucks and day cabs. Sharing the same cooled EGR, VGT Turbocharger, XPI fuel system, electronic controls and aftertreatment system seen on the ISX15, it will be offered with ratings from 310 to 425 hp and torque from 1,150 to1,650 lb ft.

Detroit Diesel showed off its new BlueTec DD16 at the Louisville show, completing the trio of DD engines — the 13 and 15 being the other two — that will serve as a global engine platform for all of Daimler, Mercedes included. This one will be made in Redford, MI., but the company will also have plants in Germany and Japan making variations on the theme. We’ll see the DD16 starting in March of next year, first in Western Stars. ‘BlueTec’ is the moniker applied to Daimler SCR engines.

PASSIVE RESISTANCE: Like its Mack stablemates, this
2010 Volvo D13 won’t do active DPF regens.

At 15.6 liters, the Detroit Diesel DD16 is aimed at owner-operators, specialized heavy-hauling applications, and premium small fleets. It will be offered with conventional and multi-torque power ratings from 1,750 to 2,050 lb ft of torque and 475 to 600 hp.

The DD16 has a wide, flat torque curve that peaks at 1,100 rpm. Its air management system features turbo compounding that converts exhaust-gas energy into useable horsepower. Its electronically controlled ACRS fuel system optimizes injection events within each stroke. The highest, or ‘amplified’, fuel pressure is generated within the injectors, meaning reduced pressure throughout the rest of the system and greater component reliability, not to mention lower fuel use.

Other key features of the DD16 include its advanced cooling system, which stabilizes operating temperatures and reduces fan on-time; and dual overhead camshafts, which better control the air-to-fuel mixture and improve torque response.

Mack and Volvo had ’010 engines installed in trucks in their displays, and Volvo powertrain guru Ed Saxman waxed poetic about their various features. He promised that 2010 Volvo trucks equipped with SCR emissions systems will not undergo driving or parked active regeneration of their diesel particulate filters during normal highway operating conditions. As with the others above, Volvo and Mack integrate SCR and DPF technologies and will have to use only passive regeneration, based on extensive testing in customer fleets.

That’s a boon, needless to say, though Saxman did allow that some vocational trucks that don’t see the highway and maybe sit idling for long periods might not escape an occasional active regen. Cummins wouldn’t say ‘never’ an active regen but said ‘seldom’ instead.

Passive regeneration of the DPF eliminates the need to inject diesel fuel into the DPF to oxidize accumulated soot, and means slightly reduced fuel consumption, reduced thermal cycling of expensive catalysts, and somewhat lower operating costs. It also simplifies vehicle operations by freeing the driver from having to keep track of when an active regeneration needs to take place.

Volvo says it has about 30 EPA ’010 test trucks in customer fleets with over two million miles of operation — but no active regens. Another 63 ’010-spec test trucks have been driven more than nine million miles without an active regeneration.

One Mack customer, Burns Motor Freight, has a test truck with a 2010 MP10 engine and about 60,000 miles on the clock. The fleet hauls building materials on the east coast from Maine to Florida, and has yet to see an active regen on that ’010 engine, Mack says. They handle DEF “just like windshield washer fluid or antifreeze.”

On a final note, neither of the Paccar companies, Kenworth and Peterbilt, was at the Louisville show and their 2010 12.9-liter MX engine has not been formally launched. Based on a well respected DAF European engine, it will be built in a new engine plant being constructed near Columbus, Miss. Construction has been delayed, however, and the timing of the MX engine’s arrival on the scene is unclear. The first 2010 MX engines will be imported from the company’s plant in the Netherlands. They too will use SCR.


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