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September 06, 2010 |

Special Reports

Tier 4 Interim

Big changes in store for new equipment next year … and 2012 … and 2014.

By Tom Jackson

It’s just three months and counting before the Environmental Protection Agency’s Tier 4 Interim regulations for non-road engines takes effect for most medium to large horsepower bands. And when it does, the new machines rolling out the factory doors on January 1, 2011, will be like nothing you’ve seen yet.

And 2011 is just the halfway point of a long phase-in period that started in 2008 and continues to Tier 4 Final, which comes due in 2012 to 2014. The reason you didn’t hear much about Tier 4 Interim between 2008 and 2010 was that those years covered only a small horsepower band with small displacement engines, and the emissions reductions were taken care of by tweaks to existing designs. The interim regulations for next year cover engines from 174 to 751 horsepower and in 2012 the regs catch engines from 75 to 173 horsepower.

But everything that can be tweaked has been tweaked. The new 2011-2012 engines will put out far fewer exhaust emissions: 90 percent less particulate matter (PM) and 50 percent less oxides of nitrogen (NOx) than their Tier 3 brethren. To do so, they will in most cases require the use of diesel particulate filters (DPFs), higher levels of exhaust gas ratio (EGR), ultra low sulfur diesel fuel (ULSD) and a new low-ash engine oil formulation – the American Petroleum Institute’s CJ-4 category.

It’s a smorgasbord of new acronyms to learn, but more importantly these changes will affect the cost, maintenance and to a small extent the performance of the new equipment going forward.

The DPF

The biggest visible difference between the Tier 3 and 2011 Tier 4 Interim engines is the DPF. Its size will vary depending on engine displacement, but for heavy equipment in general they’re about 3 feet long and 12 to 18 inches in diameter. These trap particulate matter in the exhaust stream.

The DPF and exhaust units on many Tier 4 interim machines are packaged as one unit to save space.

DPFs are not new technology. Almost a million of them have been installed in passenger cars in Europe since 2000. And they’ve been standard equipment on all heavy diesel truck engines since 2007. The term DPF is a bit of a misnomer, in that most DPFs also contain a diesel oxidation catalyst (DOC) in line with the DPF that is often part of the same canister. But many in the industry are using the term DPF to describe an integrated DPF/DOC.

Hot exhaust gases will help burn off the soot that builds up inside a DPF. This is called “passive” regeneration. The hotter the machine runs, the cleaner the DPF will stay. The more you idle, the sooner it will start to clog up, creating backpressure. When that happens the engine will shoot a burst of fuel into the DPF, which quickly burns out the residue and restores normal exhaust pressure. This is called “active” regeneration.

A PRE-BUY PROBLEM?

In a survey of dealers by Construction Equipment Distribution magazine, 67 percent of respondents said they anticipated pre-buying of 2010 equipment to avoid price increases on Tier 4 equipment.

The DPF is an essential component for reducing emissions in Tier 4 interim engines going forward. In larger horsepower engines it may need periodic removal for ash cleanout.

“In both of these modes it should be transparent to the operator,” says Joe Mastanduno, product marketing manager, engine/drivetrain, John Deere. “The operator never needs to intervene.”