Clean Diesel Technology For Off-Road Engines and Equipment: Tier-4 and More - Regulations
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Clean Diesel Technology For Off-Road Engines and Equipment: Tier-4 and More

Article Date: 01-01-2011
Copyright(C) 2011 Associated Equipment Distributors. All Rights Reserved.

Editor’s Note: AED was among five leading off-road equipment industry associations to publish a “frequently asked questions” (FAQ Report) about Tier-4 technology, the next generation of clean diesel emissions standards established by the U.S. Environmental Protection Agency (EPA) under the federal Clean Air Act. The following groups collaborated with the Diesel Technology Forum (DTF) on this Tier-4 FAQ report: 
  • Associated Equipment Distributors (AED)
  • Association of Equipment Manufacturers (AEM)
  • American Rental Association (ARA)
  • Farm Equipment Manufacturers Association (FEMA)
  • North America Equipment Dealers Association (NAEDA)
Please look for CED’s exclusive update on page 45, gauging dealer sentiment on T-4 machine availability and more.

Clean diesel technology is now the standard for all new technology, everything from new passenger cars and pick-up trucks to highway commercial trucks. Clean diesel is a system of three key parts: cleaner diesel fuel, advanced engine technol-ogy and aftertreatment. Now, start-ing in 2011, this new generation of clean diesel technology for off-road engines and equipment known as Tier-4 will be making its way onto the construction and industrial jobsites and farm fields around the country. This paper describes the milestones and technology and what it means for dealers, distributors, mechanics and those involved with operating diesel engines and equipment.

What is Tier-4?
Tier-4 refers to a generation of federal air emissions standards established by the U.S. Environmental Protection Agency (EPA) that apply to new diesel engines used in off-road equipment. Essentially it requires manufacturers to reduce the levels of particulate matter and oxides of nitrogen (NOx) to a level that is 50-96 percent lower than exist-ing generation of diesel engines. It is important to note that Tier-4 emissions requirements apply to new products only and do not apply retroactively to any existing machines or equip-ment. (See section on retrofit). EPA and California have adopted the same standards, so there are no unique Tier-4 diesel emissions standards that apply in California.

Why Are These Changes Being Made?
Through the Clean Air Act, EPA establishes national clean air standards that determine levels of allowable emissions (ozone, fine particles, etc.) in the air. From that, sources of these emissions (cars, trucks, tractors, power plants, other industry) are regulated by EPA and the California Air Resources Board to control the volume and types of emissions. Each state or regional area with levels of emissions that exceed the standards must develop a plan to improve air quality and meet the clean air requirements established by EPA. Introducing new cleaner diesel engines will aid in state and regional clean air compliance.

How Were the “Tiers”  Established? What Are the Tiers?
The “tiered” series of emissions regulations has been in effect over the last 13 years governing new off-road engines and equipment. These standards establish progressively lower allowable emissions of nitrogen oxides and particulate matter. It is complex system and its compliance dates are based on the size of engine (in hp and /kW-hr) and other factors. The Tier-4 standards provide manufacturers with a flexibility provi-sion and include an interim step – Tier-4 interim – which requires substantial reduction in PM emissions and flexibility in lowering oxides of nitrogen. A Tier-4 final step includes additional reductions in NOx and HC emissions). View detailed table of these standards along with a graphical display.  A Tier-0 engine has basically no modern emissions controls and may be referred to as unregulated and is likely to be a mechanically controlled engine rather than electronic. Each progression of standard level Tier-1, Tier-2, Tier-3 engines all are lower in emissions and more advanced technologically than the previous generation. The use of electronic engine controls, new higher pressure fuel injection systems and advanced turbocharging are all technolo-gies that reduce emissions and aid performance.

Once the Tier-4 Engines Come on the Market, Can I Still Order a Tier-3 Engine?
According to federal law and EPA regulations, depending on the machine, manufacturers will typically only be able to produce the Tier-4 engines after the established deadlines. However, equipment dealers can sell inventories of engines and equipment from the previous generation technology (Tier-3) until the inventory is depleted. Each engine and equipment OEM may have different technology and transition plans, so it will be important to understand these requirements for each machine and horsepower rating of each engine and each manufacturer. Under the EPA rules, manufacturers are provided with flexibility in meeting the requirements. Also, machines slated for export outside the U.S. are treated differently.

Do the New Tier-4 Engines Require Different Fuel?
Yes! New Tier-4 generation engines and equipment will require the use of ultra-low sulfur diesel fuel (ULSD), which has no more than 15 ppm sulfur. This fuel has been used since 2006 in on-highway vehicles. Older off-road machines and engines can continue to use the higher sulfur fuels which will be available in diminishing quantities nationwide until December 2011. Supplies of the old “higher sulfur” diesel fuel will be diminishing rapidly beyond 2010 but still may be available in some more remote locations and areas of the country. (For more information on clean diesel fuel requirements visit

We Know the New Tier-4 Engines Will Be Different from Previous Engines, But How Will They Be Different?
While each manufacturer will pursue their own technology path and emissions compliance strategy, there are a number of new technologies coming on many Tier-4 engines and equipment. For the equipment, the changes likely to be most noticeable are in the packaging and placement of the aftertreatment system and the increased size of the air intake system to accommodate the needs for increased airflow and cooling. New changes to the engine will likely mean that engine compartments may be reworked to manage the new systems. Some OEMs have indicated they will package any new exhaust system configuration inside reworked sheet metal skin while others will place the systems in their traditional locations with additional shielding and mounting hardware to accommodate the heavier exhaust system components.  Most Tier-4 engines will be electronically controlled, meaning that a computer will monitor and adjust the fuel and air mixture to optimize emissions and performance for the engine on a real-time basis. In addition, changes in the engine will include new and different systems to accommodate the increased heat rejection of the new engines. For the first time, most off-road equipment will likely incorporate emissions control technology in the exhaust system, such as a catalytic converter and/or particulate filter, typically in place of the existing muffler and exhaust system.  Some of these new exhaust aftertreatment systems mean that the pipes and placement of the muffler and exhaust may be different than previous generations of equipment, or potentially larger in size to accommodate the new func-tions and in some cases hotter temperatures of the exhaust.  There are two primary technology pathways for meeting the Tier-4 requirements: exhaust gas recirculation (EGR) or selective catalytic reduction (SCR).

Some Tier-4 engines will include use of cooled exhaust gas recirculation (EGR). EGR is a technique that recirculates a portion of the exhaust gases back into the combus-tion chamber, which has the effect of lowering the combustion temperature and reduces formation of NOx. This system will add additional manifolds and plumbing around the engine. 

One of the biggest changes for engine and equipment dealers is that some engines/machines will utilize a new emissions control technology system known as selective catalytic reduction (SCR). This technology is also designed to reduce emissions of nitrogen oxides. Widely used in Europe on heavy duty trucks and in some U.S. stationary industrial and power generation settings, SCR technology is new to the U.S. for mobile on-road and off-road applications in 2010. The majority of heavy-duty truck manu-facturers began using SCR technology in their 2010 products, along with a number of light-duty diesel car manufacturers, and some manufacturers will use this in their off-road equipment offerings. 

In this SCR system a special catalyst is positioned in the exhaust stream/muffler system downstream from an active spray dosing system that periodically sprays a mist of a chemi-cal reagent called diesel exhaust fluid (DEF), or aqueous urea - to react with the exhaust nitrogen oxides and lower tailpipe emissions. Depending on its size, a machine will have a storage tank holding anywhere up to 15 gallons of liquid DEF. The DEF dosing system, supply and return tubing and control and monitoring functions are all integrated into the engine electronic controls. DEF consump-tion is dependent on equipment utilization, load factors, idle time, etc. Manufacturers are optimizing SCR technology and DEF tank sizes such that DEF tanks need to be replenished in conjunction with key maintenance intervals. Indicator lights on the dash will warn the operator when the DEF supply is running low and should be replenished. If it is not replenished, upon a series of start-ups, the machine will eventually revert to a “limp” mode where engine perfor-mance is de-rated until the DEF fluid is replenished and the integrity of the emissions control system is restored. DEF supply has been growing for the on-highway vehicle market. It is generally expected to be more widely available as more engines and vehicles that require it are produced. 

Tier-4 engines and machines may have other differences depending on manufacturer. These could include changes in horsepower ratings, smaller engine displace-ments, and differing power and torque performance, higher fuel economy and other factors.

How Will Tier-4 Engines Affect the Value of My Trade-Ins?
Anytime a new engine or machine is introduced into the market, it sets a new standard for potential purchasers who weigh the costs and benefits of upgrading to the new technology with keeping their older technology. General economic conditions and the demand for new technol-ogy versus “older” technology influence the resale and equipment trade in markets. It is unknown whether or not introduction of the Tier-4 emissions technology will have any particularly different impact on the value of pre-Tier-4 equipment and engines. 

However, equipment owners considering acquiring older/used engines and equipment should be aware that future construction projects and bids may include consideration of the ages and or emissions performance of the fleet of machines used on the prospective project. Emissions performance of both new and existing equipment should be evaluated together as contractors consider trade and resale options.

What Additional Technician Training and Certifications Are Going to be Needed?
Reducing emissions down to near zero levels will introduce a number of changes in engine and equipment design to accommodate the new technologies into the equipment. Each manufacturer will determine their own product compliance strategy. These changes could include devices such as particulate filters, oxidation catalysts, lean-NOx traps, or SCR that are integrated into the existing exhaust and muffler systems. 

Technicians will need to have a general familiarity with electronically controlled engines, exhaust aftertreatment control devices, the concept and practice of measuring backpressure, along with the general exhaust equipment maintenance and operation. New operator warning lights and dashboard indicators will likely be included by some manufacturers to denote levels/conditions of new diesel exhaust fluid, or the indication of an active particulate filter regeneration event that might require special attention. Some Tier-4 engines/machines may use particulate filter technology that could require periodic maintenance and cleaning and/or removal. This may also involve some new equipment in a service facility such as an oven or cleaning cabinet to fully service the filters. Some of these functions can be performed by vendors off-site. 

For manufacturers that utilize SCR technology, service employees will need to be trained in the general aspects of SCR technology including the basic SCR components on the machine (SCR catalyst, storage tank, spray nozzle and plumbing systems), fluid flows and pressures and trouble-shooting. Training on the safe handling, storage, disposal and dispensing of diesel exhaust fluid, including its mate-rial safety data sheet (MSDS), is also strongly suggested.

What Additional Dealer Diagnostic Equipment Will Be Needed?
No specific diagnostic equipment requirements can be speculated at this time. However, if a manufacturer uses an SCR emissions control technology on their engine or machine, this will require that service facilities maintain supplies and dispensing equipment for DEF, commonly known as aqueous urea, in quantities to service Tier-4 engines with this technology.

Will There Be a Phase-Out For Engines, or Will My Engine Be Grandfathered for at Least a While? And if there is no grandfather clause, will consideration be given to compensate users with older equipment and dealers with used stock?
The Tier-4 requirements apply only to new engines – includ-ing those sold in California and all other states. There is no federal requirement to upgrade any existing engine to the new Tier-4 standards. California is pursuing separate state law requirements for the modernizing and upgrading of off-road machines and equipment in that state. (For more information see

The Tier 4s are Coming, the Tier 4s are Coming But When?
By Joanne Costin
Despite the highly publicized Jan 1, 2011 deadline for Interim Tier 4 regulations (IT4) for engines in the 175-750 hp range, manufacturers are playing their cards close to the vest as far as specific launch plans or strate-gies. But manufacturers are communi-cating with their own dealers. Nearly two thirds (64 percent) of AED dealers who responded to a recent survey indi-cate that they are able to tell customers specifically when IT4 machines will be available. Sixty-two percent of dealers are “somewhat” or “very satisfied” with the job their primary manufac-turer has done to prepare their service teams for Interim Tier 4. However, that doesn’t mean dealers aren’t worried. More than 54 percent of dealers surveyed are “somewhat” or” very concerned” about meeting the demand for Interim Tier 4 machines. Several dealers noted that rollout schedules are “subject to change.”

A worldwide surge in demand for construction machinery may cause added difficulty for manufacturers who are already challenged to schedule the introduction of new Interim Tier 4 models without gaps in availability. According to Joe Mastanduno, product marketing manager, John Deere Construction and Forestry, worldwide demand is nearly double what it was last year, and that has caused longer wait times for machinery. Nearly half (45 percent) of AED dealers reported experiencing difficulties or delays in obtaining Tier 3 machines in the last month.

However, Mastanduno believes Deere is better equipped to handle this situation today than they were three or four years ago, simply because their plants are more flexible. “Today, one plant will produce Tier 2, Tier 3 or Tier 4 machines going down the same line,” explained Mastanduno.

“As far as response time to the market, we think we are in pretty good shape,” he added. “We think our system is probably the most responsive in the industry.”

One dealer described the rollout process as a “competitive nightmare,” that would only be resolved when all products are introduced.

At Deere, construction machines will receive a high priority versus other equipment the company makes, due to the proliferation of in-use emissions rules contractors are facing. 

Mastanduno anticipates that high-volume machines will be among the first to roll off the assembly line. Demand for IT4 will likely be greatest in urban areas, where in-use emissions regulations apply.

Deere was the first manufacturer to introduce a machine with an Interim Tier 4 option on the 744K 4WD loader back in July 2010. Since then, dealers have placed them in their rental fleets and end-users have had an oppor-tunity to experience the machines. Caterpillar, Cummins, Komatsu and Volvo all announced certification of IT4 engines in 2010.

“By ConExpo we will have a lot of machines on the floor that will be production machines,” said Mastanduno. “Our approach is to look at the next step – what is coming after Interim Tier 4.” 

Dealers not only face Interim Tier 4 availability issues, but also resistance to the higher prices and new technol-ogy that comes attached to these machines. After all, equipment users aren’t forced into buying IT4 technol-ogy. Nearly 21 percent of dealers reported that their customers were “very concerned” about integrat-ing Tier 4 into their fleets, while 49 percent were “somewhat concerned.” Other dealers believe that few custom-ers understand the implications Tier 4 will have on their operations. 

However, dealers who embrace these challenges stand to gain, as customers look to them for advice and support. Not only will dealers help customers find the right machine, but also the right emissions solution. At the same time, the new regulations will make forecasts increasingly complex, as dealers try to predict demand not only for various models, but also for new emissions standards.

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