Equipment Manufacturers Weigh in on Final Tier 4 Emissions Regulations

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.

“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.

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Such fuel injection technology enables diesel fuel to be injected, depending on the manufacturer, three to five times per cycle, whereas before it was just one injection of fuel per cycle. “That helps it burn cleaner and makes the combustion process less violent,” Knipfer said. “It’s not one big puff of diesel fuel exploding. It’s three to five smaller puffs.” That also reduces “diesel knock,” Knipfer commented — the distinctive sound long associated with diesel-powered engines.

Diesel particulate filters are designed to help reduce emissions of unburned diesel fuel that makes it through the engine. “The engine isn’t 100% efficient,” Knipfer said, “so that [some] fuel makes it all the way through the engine and gets in the exhaust.”

If a tractor or excavator is equipped with a diesel particulate filter, then use of ultra low sulfur diesel (ULSD) and engine oil meeting API CJ-4 specifications is mandatory, Kubota’s Schroth noted.

John Deere stated earlier this year that it was taking a “planned building-block approach” to meet final Tier 4 emissions regulations.

The company said that regulatory dates for engines 75 hp and above will be implemented in stages starting in 2014 and 2015. Particulate matter levels established by interim Tier 4 regulations will be maintained, but regulations mandate an additional 80% reduction in nitrogen oxides (NOx) from previous regulations.

To meet final Tier 4 emissions regulations in some power categories, John Deere developed an “Integrated Emissions Control” system — an after-treatment solution paired with an interim Tier 4 engine platform, featuring cooled exhaust gas recirculation (EGR). The John Deere Integrated Emissions Control system will typically consist of a diesel oxidation catalyst, diesel particulate filter, and a selective catalytic reduction (SCR) system, the company said.

Consisting of an exhaust filter and SCR after-treatment components, the Integrated Emissions Control system will allow John Deere engines to utilize less diesel exhaust fluid (DEF) than alternative interim Tier 4 SCR technology solutions, the manufacturer said.

Lower DEF consumption means DEF tank size can be smaller — minimizing the impact on vehicle applications, extending DEF filter service intervals, and reducing operator involvement, the manufacturer stated. The Integrated Emissions Control system will be monitored and controlled by the John Deere engine control unit (ECU).

John Deere final Tier 4 engines will operate with traditional ultra-low sulfur diesel and biodiesel 5% to 20% (B-5 to B-20) blends meeting applicable ASTM standards, the company said.

A Price Increase on the Horizon?

Some manufacturers were reluctant to discuss whether there would be price increases resulting from technological enhancements they were making to their products to satisfy final Tier 4 requirements, but Kubota’s Schroth noted, “The need for price increases, if any, varies by model, horsepower, and level of additional technology required to meet emissions regulations.

“If, for example, a certain model needs to be equipped with common rail injection and diesel particulate filter to meet iTier 4 or Tier 4 requirements, and if such technology was not necessary to meet the previous tiers, then there may be a price increase,” Schroth said. “However, often the more sophisticated technology results in an improvement in fuel economy and/or performance, and partially or entirely compensates for such price increases.”

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Tier 4: Maintenance Changes Expected to be Minimal

Maintaining Tier 4-compliant equipment is not expected to require major changes to existing maintenance practices and procedures, manufacturers said.

Ray Schroth, director of service for Kubota Tractor Corporation, said general maintenance operation and frequency, such as oil changes, inspections, and lubrication, differ by model, but they will not change specifically and in conjunction with the introduction of Tier 4 models.

Some Tier 4-compliant tractors equipped with a diesel particulate filter will require removal and professional cleaning of that filter periodically, but not more frequently than every 3,000 hours, Schroth said. Kubota will offer a filter exchange service through its dealers to accommodate this need, he added.

“We see no need for specialized training to perform regular standard maintenance on Tier 4 or interim Tier 4-compliant Kubota tractors currently on the market,” Schroth said.

Chris Knipfer of Bobcat said the manufacturer’s Tier 4 equipment requires “a much more advanced fuel filter.” While the change interval remains the same, “something new is that water has to be drained from that filter,” he said. This is done by opening an orifice on the bottom of the filter.

“Our machines notify the operator when the filter needs to be drained,” Knipfer added. A flashing icon in the cab alerts the operator. If the operator ignores the alert, the icon flashes again, and the machine derates power to get the operator’s attention.

Read All About It

For equipment operators and technicians, Ken Emmett, truck product manager for Terex Construction, has this advice: Be a bookworm.

One of the most overlooked resources is the reference material that comes with every unit. “Technicians can really boost their knowledge by reading the operating and service manuals that come with the [off-road] truck,” says Emmett. “More than 90% of the questions we receive are covered in the books.” This advice applies as well to off-road equipment that comply with final Tier 4 requirements, Emmett stresses.

Further, it is advice meant for all — not just those who are new to the field of vehicle and equipment service, Emmett’s colleague, Stu Thompson, product service manager for Terex Construction, emphasized. It’s meant for the most seasoned technician too. Every manufacturer’s maintenance requirements are different, Thompson said, and even different models can have different maintenance requirements.

Technicians must stay abreast of changing designs and the required maintenance intervals. This is why it is so important to study the manufacturer’s operating and service manuals when first received and not rely on field experience. Failure to follow recommended service intervals outlined in the manuals can reduce the service life of a major component and void the truck’s warranty.

Ray Schroth, director of service for Kubota Tractor Corp., echoed this counsel, noting that a manual, provided with each Kubota tractor, “spells out all maintenance and operating requirements and specifications.”

SOURCES:

• Ken Emmett, truck product manager, Terex Construction
• Chris Knipfer, marketing manager, Bobcat Company
• Ray Schroth, director of service, Kubota Tractor Corp.
• Stu Thompson, product service manager, Terex Construction