In late March, the CONEXPO construction equipment exposition in Las Vegas saw several companies unveil new products. Cummins, however, may have stolen the show when it displayed one of its next-generation, Tier 4 Final (T4F), engines, even though that emissions standard doesn’t come into effect until 2014. The CONEXPO reveal makes Cummins the first major manufacturer to publicly reveal plans for its future line of off-road engines, although Caterpillar also took the opportunity to introduce two low-horsepower T4F models.
We’ve only just seen farm machinery affected by the new interim Tier 4 (IT4) standard which came into effect in the U.S. and Europe in January (in Canada the regulation is in the process of being adopted, but it is not yet in place). Farmers are just getting used to hearing about this generation of engines (and you’ve likely read a lot about them here inGrainews). Now, farmers get a chance to see a sample of what technology is on the horizon.
EMISSION REDUCTION COMBO
Cummins stayed with CEGR (cooled exhaust gas recirculation) for its current IT4 off-road engines. But engineers have had to throw the whole book of existing technologies at them to meet the near-zero emissions levels required for T4F. The company
will use both SCR (selective catalytic reduction) and CEGR on the same engines to get to the next level.
That’s really no surprise. Engineers from most manufacturers have long speculated that using both systems would probably be necessary to meet T4F. But Cummins will use the updated version of its existing IT4 diesel particulate filter (DPF), the Cummins compact catalyst, on most of its engine line.
The company calls the new complete, after-engine exhaust treatment the CCC-SCR (Cummins compact catalyst-selective catalytic reduction system). “With the addition of SCR, we now have the ability to precisely balance NOx reduction between after-treatment and cooled exhaust gas recirculation on the engine — giving us more control over the combustion formula than ever before,” says Jeff Weikert, vice-president of Cummins MidRange Engineering.
Cummins will use CCC-SCR as a standard treatment on all its engines through the 75-to 400-horsepower range. That means aside from the QSL9 (nine litre) engine the company displayed at the Las Vegas show, the QSB3.3, (3.3 litre) QSB 4.5 (4.5 litre) and QSB6.7 (6.7 litre) will also see the CCCSCR after-engine treatment system installed on them.
The company says the move from IT4 to T4F will be a seamless one. The basic design of the next-generation engines (without the emissions systems) is almost identical to current IT4 models. “This ability to move forward to meet the near-zero emissions standards is pre-designed into the existing engine platform, with no significant change required for
Cummins and Caterpillar introduced Tier 4 Final-compliant engines at the CONEXPO, construction equipment show, in Las Vegas in late March. Cummins engines will use both CEGR (cooled exhaust gas recirculation) and SCR (selective catalytic reduction) on the same engine to meet that future emissions standard.
engine systems or installation profile,” reads the Cummins press release.
Cummins is no stranger to SCR technology. Its on-road engines have been using it since 2005, but the company calls the system intended for T4F engines “a next-generation design.” Here is how the overall emissions treatment will work.
A variable-geometry turbocharger will still cycle some exhaust gas back through the cylinders. As exhaust leaves the engine, it is filtered through the CCC (the updated particulate filtering system), which Cummins says passively oxidizes particulate matter using a catalytic coating and substrate. The new CCC design is also smaller than existing DPFs used on current Cummins engines above 175 horsepower.
After exhaust passes through the CCC, it is treated by the SCR system. “The system incorporates a copper zeolite-based catalyst capable of up to 95 per cent NOx conversion and able to operate more efficiently at lower temperatures,” the press release continues. This allows for lower diesel exhaust fluid (DEF) usage rates.
For its two larger engines, the QSX15 and QSX11.9, Cummins will combine its existing DPF with the same next-generation SCR system used on the smaller models. Once again, the basic IT4 engine platform will remain essentially unchanged. “The QSX15 and QSX11.9 engines for Tier 4 Final 2014 will be almost identical to the QSX engines introduced to meet Tier 4 Interim in 2011,” is how Cummins explains the big-engines’ upgrade in a separate press release. As well, the top horsepower rating for both will jump with the next-generation release. The QSX15 will jump to 675 from 600, while the QSX11.9 climbs to 525.
Although Cummins is first out of the gate to show off their line of next-generation engines, all the other manufacturers are well into testing theirs. But they’re still playing the cards close to the vest. Here’s how John Deere’s spokesman summed it up during a press conference at the AgConnect Expo in Atlanta back in January: “Quite frankly, we’ve already decided on our Tier 4 Final solution. But we can’t reveal that right now,” he said. And, he added, Deere will be open to dumping it in favour of any new and better technology developed in the meantime.
He also noted Deere will need to lock in its decision on new engine design 14 to 18 months before the January 2014, implementation date. It’s unlikely that company will release anything official on its future designs any earlier than mid-2012. None of the other companies are yet to make any official comment on their T4F designs, either.
The two engines introduced at the CONEXPO by Caterpillar also meet T4F standards, but farmers likely won’t see many of them on farm equipment. These two, relatively small, four-cylinder 1.5-and 2.2-litre engines put out 33 to 61 horsepower and will use active regeneration DPF technology.
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had to use every available
technology to meet final Tier 4 regs