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Stepping up to Tier 4

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June 1, 2012 by David Godkin

We’ve still got time. That seems to be the failsafe view of contractors facing a mandatory shift in Canada to interim Tier 4 emission standards in some new off highway equipment at the end of 2014 and to full Tier 4 standards by the end of 2018. Until then, some contractors have chosen to delay their purchases of Tier 4 engine equipment as long as they can; others continue paying fees for the right to produce higher levels of nitrous oxides and particulate matter using older engine technology.

Manufacturers in the meantime, are trying to help contractors understand how they can meet Tier 4 standards without blowing a hole in their equipment budgets or negatively impacting their operations.
Delaying the inevitable

EPA-mandated interim Tier 4 regulations went into effect January 2011 across the 174 to 751 hp (130-560 kW) power category, requiring diesel engines to reduce particulate matter (PM) exhaust emissions by 90 per cent and NOx exhaust emissions by 45 per cent, compared with the Tier 3 and Stage IIIA emissions standards. Beginning in 2014, off-highway diesel engines in this power category must reduce NOx emissions by a further 80 per cent compared to 2011 levels. In 2014, NOx and PM exhaust emissions are expected to be reduced by 90 per cent compared with current Tier 3 and Stage IIIA levels.

Some companies can delay their purchase of new Tier 4 equipment by taking advantage of transitional engine allowances. For example, 225 kW engines meeting Tier 3 standards will be allowed into Canada up until December 31, 2017, after which they must meet full Tier 4 standards. For Doug Morris, director of product marketing for Komatsu, the reception to Tier 4 has been a mixed bag, with some contractors delaying purchases over fear of the unknown and others forced into Tier 4 purchases by jurisdictions such as New York. There, contractors are required to apply “best available technology, or make modifications to their equipment in order to meet Tier 4,” says Morris. For those not so constrained, delaying Tier 4 compliance is directly related to cost. Finning emissions engineer Ryan Kisko puts it bluntly: “If you’re a company operator and you want to be green, you gotta put some green into your pocket, too. So who wouldn’t have gone and tried to buy the pre-Tier 4 engines?”  

Most agree delaying Tier 4 equipment purchases helps contain costs initially, but that eventually all pre-Tier 4 equipment will be out of service. “Customers will have no choice but to buy Tier 4 Interim or Tier 4 Final products, because that’s what’s mandated by the law of the land,”says Genie senior product manager Scott Krieger. Kisko asks: “What are you delaying it for anyway? You’re just going to end up having to buy one in the future anyway.” Some want to see Tier 4 engines tested before buying new, Kisko adds, “let someone else run it and prove it.” That strategy is borne out by Island Asphalt’s equipment manager Jon Futer. “For us being a smaller company not making as many purchases, we delay it to make sure they get the bugs out,” he chuckles.

How Tier 4 technology works
Selective Catalytic Reduction (SCR)—combines exhaust gases with ammonia in the form of urea (or diesel emissions fluid, DEF) and passes the mixture over a catalyst. This converts harmful NOx into elemental nitrogen, water vapor and carbon dioxide. According to MTU Onsite Energy, a division of engine designer Tognum, approximately one gallon or 3.79 litres of DEF is required for every 20 gallons or 75 litres of diesel fuel that is burned. In some jurisdictions SCR will be combined with a Diesel Particulate Filter (DPF) to meet Tier 4 Final regulations.

Diesel Particulate Filter (DPF)—Particulate matter in various off highway engine brands is removed through passive regeneration; i.e., burned off at normal exhaust temperatures. To remove larger particulate build up, companies such as Cummins and Komatsu employ filters and hydrocarbon dosing technology that involves injecting small amounts of fuel into the exhaust stream to produce a chemical reaction that generates sufficient heat to burn off  the soot.

Exhaust Gas Recirculation (EGR) works by recycling a small amount of cooled exhaust gas back into the combustion chamber, cutting combustion temperatures and NOx emissions. EGR-equipped engines are very effective at reducing NOx and will not require SCR after-treatment to capture the remaining NOx and PM. Because it increases particulate emissions, however, it will likely be used in conjunction with DPF to meet both Tier 4 Interim and Tier 4 Final regulations.

Both Cat and Cummins employ a cooled EGR system to remove NOx, in Cummins’ case reducing these gas emissions by 45 per cent compared to Tier 3.

Currently, DPF and hydrocarbon dosing technology appears to be the technology of choice for many equipment manufacturers. Like EGR, the best part about DPF technology is that it kicks in automatically. “During regeneration a symbol pops up on the monitor panel that indicates it is occurring,” says Morris. “There’s no effect on performance.” But Tim Stewart is not so sure. In fact, the general manager for Imperial Paving in Burnaby, B.C. says his main reservations around Tier 4 technology for off-road equipment stems from his experience with similar technology in on-highway emission equipment. Last October in the middle of a job, on-board systems designed to identify and automatically clean out soot from a truck and trailer unit brought the machine to a complete halt.

“I’m sitting there with a truck and trailer full of hot mix asphalt and I can’t get it to the paver because the truck won’t move. The computer is telling me it has to flush it out. It’s sitting there at high RPMs in the middle of a residential area.”

Kisko is concerned about the effectiveness of dosing regeneration systems at cold temperatures. “I have yet to see any data that shows that at -40 that chemical reaction will still create enough heat for full and proper regeneration. It is obviously a concern.” Because Cat uses on-board incineration to create an actual burn, Kisko says it “has no problem” generating the heat needed to reduce soot under cold weather conditions.

But on-board incineration devices pose a concern for engine designer and manufacturer Kubota in the added space the device takes up on an already well-loaded vehicle. “We have some large customers in the Kubota world like Carrier and Bobcat,” says Canadian sales and marketing manager J.P. Ouellette. “Where are they going to fit all that on their reefers and skid steer loaders?” Right now the DPF has the advantage in the marketplace, he adds, but Kubota is considering introducing SCR technology after improvements are made and in time for full Tier 4 implementation.

Less or more costly? You be the judge Ultra-low sulphur fuels and low-ash engine oils are important for overall engine wear and keeping Tier 4 regeneration systems working at optimal rates. So, too, is general maintenance, with particular attention paid to cleaning the DPF. Komatsu provides two filter exchanges within five years enabling contractors to meet the EPA’s mandatory 4,500-hour clean filter requirement and avoiding additional cleaning or purchase costs.

In addition to its filter exchange program, Cat offers a portable cleaning system and larger non-portable cleaning systems at Finning dealerships. Because the entire regeneration in DPF occurs internally it is especially helpful to compact equipment operators, says Bobcat’s Chris Knipfer. “As an operator or owner you don’t take anything off or change the filter for about 3,000 hours,” at which point Bobcat owners may choose to switch out machines completely and buy a new one.

While Tier 4 technologies bring with them a
dded complexity, most agree this will not place a large additional burden on company mechanics. Engine manufacturers and dealers provide ample guidance in maintaining the filters and other components, backed up by generous service support. What remains to be seen, however, is the increased cost of Tier 4 off highway equipment overall. Relying upon EPA evidence, Environment Canada estimates the price increase on imported Tier 4 heavy equipment will be less than three per cent on average for most models.

Knipfer doesn’t believe that. Assuming additional Tier 4 costs are passed on to customers, “everything I’ve heard in our industry is that the price increase will be anywhere from seven to 15 per cent,” he says. For his part, Krieger expects about a $4,000 increase in Genie’s telehandlers as they move from Tier 3 to Tier 4 Interim requirements, with an additional $2,000 as Tier 4 Final requirements become mandatory.

Are there cost advantages to moving toward Tier 4 standards? Sure, says Knipfer. Tracking fuel consumption is much easier today, he says, because of Tier 4 influenced electronics.

“We can track fuel consumption now whereas before it wasn’t something common in the industry. A lot of customers ask for that, especially if they have a fleet and are trying to budget for the next year.”  

David Godkin is a B.C.-based freelance writer. Send comments to editor@on-sitemag.com

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