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Power lines

LOUISVILLE, Ky. - The traditional lines between engine makers, truck manufacturers and component designers appear to be blurring as the trucking industry prepares for the next round of emission standa...




LOUISVILLE, Ky. – The traditional lines between engine makers, truck manufacturers and component designers appear to be blurring as the trucking industry prepares for the next round of emission standards, to take effect 2007.

International announced at the recent Mid-America Trucking Show that it will introduce its own big-bore diesel engine line-up – ranging from 11 to 13 litres – in the fall of 2007. Volvo announced plans to begin production on its massive 625-hp offering this August.

And at the same show, Caterpillar unveiled plans for its own fully automatic transmissions for vocational customers.

The idea of “vertical integration” is common in Europe, where buyers choose engines and trucks from the same manufacturers, much like the way that North Americans buy their cars.

International’s technology has come through its collaboration with MAN Nutfahrzeuge, while the new Volvo engines will be cast and machined in Sweden, and assembled in Maryland.

There are advantages to an integrated approach, said International Engine Group president Jack Allen.

“It (the engine) will be specifically engineered to integrate leading diesel technologies with cab, chassis and systems innovations,” he said of the International engine that will include a common rail electronic fuel system capable of multiple injection events, and single overhead cam actuated with four valves per cylinder, and roller rocker arms.

The company will also continue to offer Caterpillar and Cummins power.

Meanwhile, some offerings showcased an ever-tightening connection between the engine and drivetrain.

Volvo’s new “I-Torque” technology, for example, will limit torque in startup gears to prevent spinning wheels or damage to the drivetrain, and that will allow truck buyers to spec’ lighter-than-usual rear axles and suspensions.

The approach matches torque levels to gear ratios, which are the ratio of an engine’s speed to the rotation of the transmission’s output. The 600 hp/2,050 lb-ft and 625 hp/2,250 lb-ft ratings have three torque levels matched to transmission gear ratios of more than 5:1 in low-range or startup gears, 2.6:1 and 5:1 in low and mid-range gears, and less than 2.6:1 in high-range and overdrive.

Caterpillar, meanwhile, is introducing a line of automatic planetary transmissions for vocational applications, which will be available by next year. The six-speed CX31 will be compatible with C11, C13 and C15 engines, while the eight-speed CX35 will be matched to high-horsepower C15s in on-highway vocational trucks.

In general, all engine makers appear confident that they will be up to the challenge of 2007 emission standards that call for tighter controls over particulate matter and crankcase emissions, thanks largely to the introduction of new components such as particular filters and the use of Ultra-Low Sulfur Diesel (ULSD) fuel.

The engines themselves are expected to be relatively similar to those built to meet 2002 standards, which introduced the trucking industry to such things as Exhaust Gas Recirculation (EGR) systems that control the combustion temperatures that create oxides of nitrogen (NOx).

Volvo officials, for example, say their new D16 was designed with 2007 and 2010 emission standards in mind, suggesting they can increase EGR rates and heat rejection, responding with increasing cooling capacity of a larger radiator and cross-flow charge air cooler similar to the system used in the new VT 880 Class 8 tractor.

But the debate continues to rage over whether engines built to 2002 standards will last as long as their predecessors.

Cummins officials note that its post-’02 on-highway ISX engines should be able to match the durability of earlier models, basing the claim on the recent teardown of several engines that had accumulated about 965,000 km of commercial service.

“There is no difference in durability between pre ’02 engines and post ’02 ISX engines. The proof is in the parts,” said Bob Weimer, vice-president, heavy-duty quality, during a daylong introduction to the findings held at the company’s Columbus, Ind. facility. Durability is typically measured by the point at which an engine requires an in-frame overhaul due to component wear or the excessive consumption of oil.

The company considered major components including the crankshaft, camshafts, EGR subsystem and power cylinder.

Power cylinder components had worn 20 to 25 per cent, while connecting rods and main bearings were thought to be half way through their life.

Any carbon in the intake is to be expected in an EGR engine, he added. And a Total Base Number oil analysis confirmed the cooled EGR engines were basically free of corrosion.

Caterpillar – which meets emission standards with its ACERT system – a combination of series turbochargers, variable valve control, a high-pressure multiple injection system and an oxidation catalyst – has a different story.

It claims cooled EGR engines have faced an early pitting of piston ring grooves, rings, valves and cylinder walls, and substantial soot in the inlet manifolds.

In contrast, the manufacturer says its ACERT designs create less soot.

Meanwhile, many engine makers suggest it’s too early to tell exactly how 2007 changes will affect fuel economy, but suggest that they’ll come close to current designs.

Detroit Diesel says it will actually be able to increase fuel economy of its existing 14-litre Series 60 by up to 1.9 per cent in some applications, thanks to enhancements to software, fuel injection and the flow of the EGR system.

Ultimately, fuel efficiency will depend largely on whether users follow recommended spec’s and driving habits, says Caterpillar’s Mike Powers.

“If you spec’ it right, there isn’t going to be anything different.”

Most buyers of late-model engines have been encouraged to slow down by about 100 rpm at cruising speeds, reaching about 1,350 rpm at 105 km-h, he says.

“We always said gear fast, run slow.”

But the penalty for failing to do that is growing with every change in the standards.

The one pressing challenge concerning 2007 remains the uncertainty over the availability of Ultra Low Sulfur Diesel.

“Ultra Low Sulfur Diesel enables aftertreatment. If we don’t have 15 parts-per-million sulfur diesel the engine industry is in trouble because we have designed our engines based on that standard,” said Cummins’ Christine Vujovich.

(Higher sulfur levels will require particulate filters to be changed more frequently.)

Between 1998 and 2010, oxides of nitrogen (NOx) and particulate matter (PM) emissions will have been slashed by 98 per cent.


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