Green Fleet

Equipment Manufacturers Weigh in on Final Tier 4 Emissions Regulations

Manufacturers are progressive toward the deadlines for Final Tier 4 emissions requirements for off-highway vehicles. Here, they talk about their plans for compliance and how it will affect fleets.

October 2012, Government Fleet - Feature

by Stephen Bennett

This chart from John Deere shows how EPA regulations have significantly reduced the amount of particulate matter and nitrogen oxide emissions. The European Union (EU) has similar emissions standards, named stages, that approximately correspond to the EPA's tiers. Hence, Final Tier 4 regulations in the United States are very similar to Stave IV regulations in the EU. Graphic courtesy of John Deere.
This chart from John Deere shows how EPA regulations have significantly reduced the amount of particulate matter and nitrogen oxide emissions. The European Union (EU) has similar emissions standards, named stages, that approximately correspond to the EPA's tiers. Hence, Final Tier 4 regulations in the United States are very similar to Stave IV regulations in the EU. Graphic courtesy of John Deere.
At a Glance

What EPA Final Tier 4 requirements mean for fleets:

  • A potential increase in equipment prices, possibly offset by better performance or fuel economy.
  • Almost no particulate matter (PM) and nitrogen oxide (NOx) emissions in their off-road vehicles.
  • Minimal maintenance changes, according to manufacturers.


Manufacturers are progressing toward the deadlines for final Tier 4 emissions requirements for off-highway vehicles set by the Environmental Protection Agency (EPA) even as some of their compact equipment products that meet interim Tier 4 are just beginning to reach the market.

Tier 4 emissions standards are part the Clean Air Act, a federal law to reduce air pollution. To meet Tier 4 standards in the law, manufacturers are adding clean diesel technology designed to reduce emissions of particulate matter (PM) and nitrogen oxides (NOx). The standards have been introduced in stages, depending on horsepower range. (See “Emissions Regulations by Year” chart on page 34.) With each stage, the emissions restrictions grow progressively tighter, culminating in final Tier 4, which will produce almost no PM or NOx emissions. The chart above shows how stringent regulations have become.

Smaller Engines Are Already Compliant

“Some lower-horsepower Kubota models have already been complying with ­[final] Tier 4,” said Ray Schroth, director of service for Kubota Tractor Corp., “while full Tier 4 introduction on the entire model line will not occur before 2015.”

Chris Knipfer, marketing manager of Bobcat Company, said the manufacturer’s engines that are 25 hp and below have met final Tier 4 requirements since 2008, while engines in the 25- to 75-hp range won’t even be subject to final Tier 4 until 2013; and engines such as Bobcat’s 99-hp product won’t be subject to final Tier 4 until 2015. Meanwhile, 75-hp engines that meet interim Tier 4 — the stage before final Tier 4 — “are just getting out there,” Knipfer pointed out.

Meeting final Tier 4 in the lower horsepower ranges isn’t a daunting challenge, Knipfer said. For engines 25 hp and below, “It’s just pretty much simple internal tweaks to the engine to make it run clean enough to meet final Tier 4,” he said. By “simple internal tweaks,” Knipfer is referring to changes in the fuel and air mixture to achieve cleaner fuel combustion. That’s why manufacturers were able to meet final Tier 4 requirements for those engines four years ago, Knipfer explained.

Achieving Compliance in More Powerful Engines

While lower-horsepower engines compliant with final Tier 4 requirements may already be on the market, the requirements grow increasingly strict — and increasingly difficult to achieve — in higher horsepower engines.

This chart details when each horsepower group is required to meet each level of emissions regulations. Regulations mandate that by 2015, all off0road engines up to 175 hp must be final Tier 4 compliant. Graphic courtesy of Kubota.
This chart details when each horsepower group is required to meet each level of emissions regulations. Regulations mandate that by 2015, all off0road engines up to 175 hp must be final Tier 4 compliant. Graphic courtesy of Kubota.

“It’s a lot more work to get that bigger engine to meet the requirements,” Knipfer said. “You can tweak how the engine operates only so far,” he said. “Then you have to add on diesel particulate filters (DPFs) and diesel oxidation catalysts (DOCs) and make the engine more electronic — the fuel injection system is completely different.”

For certain motors that Bobcat offers that are 75 hp and above, the OEM put in a new, computer-operated, high-pressure, common rail fuel injection system, Knipfer said. “It’s different because it’s now injecting fuel into the engine at 18,000 to 19,000 PSI, which is substantially greater than, say, Tier 3,” Knipfer said. The higher pressure turns the fuel into a fine mist that burns more completely, he said.

COMMENTS

  1. 1. Stephanie [ February 20, 2015 @ 02:05PM ]

    Will tier-3 engines become obsolete in 2015?

 

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