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Tier 4 Literature

Download Tier 4 Literature (PDF)

Cleaner Air For Everyone

Download Cleaner Air For Everyone from the 2011 Worksaver Bobcatalog (PDF)

Looking Ahead To Tier 4

:: Bobcat and Tier 4 Emissions Standards

For several years Bobcat has been working hard to ensure our products are compliant to the required federal emission standards for non-road equipment. Rest assured, this discipline will certainly carry on into the future. Emission standards, such as interim Tier 4 and Tier 4, will bring changes to the way that many machines release engine exhaust into the atmosphere. This clean diesel technology will greatly reduce the levels of harmful emissions such as particulate matter (PM) and Nitrogen Oxides (NOx) that enter the air and will improve air quality and public health for generations to come.

:: Emissions Standards History

The U.S. government, through their EPA & Clean Air Act, has provided an opportunity through Tier 4 that promotes a sustainable environment and healthy life to future generations so they have a chance to carry on what has been built and left to them. Take a look at the time line leading up to Tier 4.

:: Emissions Evolution for Compact Equipment

For several years, Bobcat machines have been changing to meet emissions standards. Review the tiers and requirements.

:: Interim Tier 4 and Tier4 Technologies

Future engine advancements and after-treatment systems will be common in many interim Tier 4 and Tier 4 compliant machines. See the Tier 4 clean diesel technologies.

:: Emissions Standards Resources

Bobcat has compiled many resources to help you learn more about Tier 4. Link to other Tier 4 information.

:: Frequently Asked Questions

Have more questions? View some frequently asked questions about Tier 4.

Looking Ahead


Donora & Webster, Pennsylvania - These two towns along the Monongahela River southwest of Pittsburgh, were the site of a lethal air pollution disaster in late October 1948 that convinced members of the scientific and medical communities, as well as the public, that air pollution could kill people, as well as cause serious damage to health. The disaster took place over the course of five days. Almost half of the area's 14,000 residents reported becoming ill, and about two dozen citizens' deaths were attributed to the badly polluted air.

Donora, Pennsylvania


London's Killer Fog - A toxic mix of dense fog and sooty black coal smoke killed thousands of Londoners in four days. The pollution cloud was enough to lower visibility down to one foot in front of you. It remains to be one of the deadliest environmental episodes in recorded history, and contributed to changing how the world views air pollution. Read full article here.

London Fog


Air Pollution Control Act - The first United States Clean Air Act enacted by Congress. In short, it identified air pollution to be a national environmental problem and declared air pollution to be a danger to public health and welfare. It also provided initial federal funds to research how air quality could be improved.


Clean Air Act - The first federal legislation regarding air pollution. It established a federal program within the U.S. Public Health Service, authorized research into techniques for monitoring and controlling air pollution, and established funding for the study and the cleanup of air pollution. Most importantly, it set standards for emissions on stationary sources like power plants and steel mills, recognized the dangers of motor vehicle exhaust, and encouraged development of standards for vehicles.

Clean Air Act


Motor Vehicle Pollution Act - An amendment to the U.S. Clean Air Act of 1963. It set the first federal automobile emission standards with compliancy deadlines beginning with the 1968 models, which were the same standards California had set for their 1966 models. These standards were reductions from the 1963 emissions: 72% reduction for hydrocarbons, 56% reduction for carbon monoxide, and 100% reduction for crankcase hydrocarbons. 1968 & 1969 - Federal testing results showed that more than half of the cars built in these years did not meet the federal emission standards that had been set in 1965.

Motor Vehicle Pollution Act


Earth Day - On April 22, 1970, Senator Gaylord Nelson created Earth Day as a way to “force this issue onto the national agenda.” 20 million Americans in different U.S. cities demonstrated support for a healthy, sustainable environment. This event has continued to be celebrated annually on this date.

Environmental Protection Agency (EPA) - Without a single state successfully developing a full pollution control program, failure of auto manufacturers to meet compliance testing, and Earth Day developing earlier in the year, action had to be taken. Congress again amended the Clean Air Act and this time created the EPA. Part of the EPA's new role was to enforce the guidelines and standards set by the newly amended Clean Air Act by performing compliances tests, enforcing performance warranties from manufacturers, and distributing fines to those that violated standards.

Clean Air Act - The amendments in 1970 were an entirely rewritten version of the original Clean Air Act. It set National Ambient Air Quality Standards (NAAQS) to protect public health and welfare, and New Source Performance Standards (NSPS) that strictly regulated emissions of a new source entering an area such as motor vehicles or a factory. Standards were also set for hazardous emissions and emissions from motor vehicles such as Carbon Monoxide (CO), Hydrocarbons (HC), Nitrogen Oxides, Lead (Pb), and Particulate Matter (PM). These emissions are still of primary concern today and are a large part of the emission standards, such as Tier 4, that are required for the future.

Earth Day EPA


Catalytic Converter - This became a significant addition to automobile exhaust systems as a result of the emission standards set in 1970.


Amendments to The Clean Air Act - The government realizes expectations of the 1970 amendments may have been too ambitious and takes actions to make more realistic goals by extending timelines on emission standards compliancy and even providing leniency to the standard set on some emissions. The first time standards for lead amounts in gasoline were set. The government began making attempts to prevent destruction of the Ozone.


The EPA further lowers lead standards for gasoline and sets standards to limit diesel particulate emissions (PM).


Heavy-duty trucks and buses begin and complete an emissions reduction process. The end result is comparable to what Tier 4 will be for compact equipment.


Cars and light trucks begin and complete an emissions reduction process. The end result is comparable to what Tier 4 will be for compact equipment.


Compact equipment evolves to meet tiered emissions standards for diesel engines, with Tier 4 being the final step in this process.

:: Emissions Evolution For Compact Equipment

Bobcat® machines have been changing to meet emission standards for several years. Many Bobcat equipment models will go through as many as five different tiers of standards: Tiers 1-3, Interim Tier 4 (iT4) and Tier 4 (T4).

You don’t have to retrofit your machines to the current emission standards. Federal regulations require that manufacturers build machines compliant with the emission standards in effect at the time of manufacture.

Standards for diesel exhaust emissions become more stringent from tier to tier. Each tier addresses numerous types of pollutants. However, Particulate Matter (PM) and Nitrogen Oxides (NOx) receive the most attention.

  • Nitrogen Oxides (NOx) contributes to ground level ozone, commonly known as smog.
  • Particulate Matter (PM) consists of soot or unused fuel found in exhaust. This type of pollution gives dirty engine exhaust its black color.
Emission Comparisons

:: Tier 1 for Compact Equipment

The first set of EPA emission standards for new non-road diesel engines is referred to as Tier 1 (date range shown in chart 1). The main goal of this emission tier was to reduce Nitrogen Oxides (NOx) emissions from these engines by roughly 30%.

Bobcat machines needed only minor internal engine modifications to become Tier 1 compliant. An improved engine combustion system lowered the output of emissions, such as NOx, with little or no impact to machine price, performance or fuel economy.

Tier1 Chart

:: Tier 2 for Compact Equipment

The second set of EPA emission standards for new non-road diesel engines is referred to as Tier 2 (date range shown above). Major focus was on NOx, hydrocarbons (HC) and particulate matter (PM). PM reductions were as much as 25% on some engines.

Direct fuel injection (DI) systems aided in further lowering emissions and were used in many Bobcat machines during Tier 2. DI also improved fuel economy and lowered average engine operating temperatures which lowered operating costs and increased engine life.

:: Tier 3 for Compact Equipment

Tier 3 standards applied to Bobcat models with engines of more than 75 horsepower (shown in chart 1). Tier 3 focused on reducing NOx emissions roughly 37% for these machines.

Bobcat utilized a Cooled Exhaust Gas Recirculation system, or CEGR, as a primary way to meet Tier 3 compliancy.

Extreme temperatures during combustion increase NOx produced by engines. CEGR systems lower combustion temperatures by several hundred degrees, reducing the formation of NOx.

Low-sulfur diesel, already in use for on-road vehicles, was also introduced for non-road vehicles during Tier 3. Low-sulfur fuel increases the life of CEGR system components.

Tier3 Chart

:: Interim Tier 4 (iT4) and Tier 4 (T4) for Compact Equipment

Further reductions to NOx and PM is the main objective. Smaller engines have less stringent emission standards compared to larger engines and modest engine updates met iT4 or T4 compliancy for some Bobcat machines. Models that have yet to become compliant to iT4 or T4 will need additional technologies to do so.

Engine Size

Currently iT4 Compliant?

Currently T4 Compliant?

New systems needed for iT4 compliance?

New systems needed for T4 compliance?

Under 25 hp





25-75 hp


(scheduled for 2013)



75-175 hp

(scheduled for 2012)

(scheduled for 2015)



Tier4 Technologies 1 Tier4 Technologies 2 Tier4 Technologies 3

:: Emissions Standards Resources

Health and Environment Benefits for All Tiers
Tier 4 is more than just emissions. It’s about changing the world for the better. Bobcat is working hard with the entire equipment industry to do our part.

  • Tier 4 standards reduce emissions from a typical non-road diesel engine by up to two-thirds.
  • The EPA estimates that in 2010, NOx emissions will be reduced by about a million tons per year – the equivalent of taking 35 million passenger cars off the road.
  • Respiratory problems and disease caused by ozone and PM will decline – as will acid rain, crop damage and smog.
  • By 2030, the EPA estimates that 12,000 deaths, 8,900 hospitalizations and one million lost work days will be prevented annually.

:: Links

Looking Ahead

Q: Where does Tier 4 come from?

A: All emissions standards, including Tier 4, are a part of a federal law named the Clean Air Act. The purpose of this law is to reduce air pollution because of its hazards to human health and the environment. The Clean Air Act is managed and regulated by a national organization known as the Environmental Protection Agency (EPA). See Tier4 timeline.

Q: Why did the federal government create the EPA and pass the Clean Air Act?

A: In the 1940s and 1950s, several world events (see tier 4 timeline) heightened awareness of the human and environmental hazards of air pollution. Over the next two decades, Congress took several steps to create emissions standards in various industries.

Q: How has Bobcat already been addressing Tier 4?

A: Bobcat machines under 25.5 hp have been Final Tier 4 compliant since 2008. Bobcat machines equal to or greater than 25.5 hp, but less than 75.1 hp have been Interim Tier 4 (iT4) compliant since 2008. For Bobcat machines that are not subject to iT4 or Tier 4 compliancy until future dates, Bobcat is committed to incorporating iT4 and Tier 4 technologies that provide the most benefits to our customers and are the most applicable to the products that we manufacture.

Q: How will Bobcat address Interim Tier 4 (iT4) for higher-horsepower machines?

A: Like other manufacturers, we are thinking hard about 2012, when Bobcat machines that fall into the 75.1 to 174.3 hp class become Interim Tier 4 compliant. Interim Tier 4 technology abilities: Machine performance — iT4 technologies can produce more combustion energy to increase engine torque output. Operator comfort — iT4 technologies can reduce engine noise levels.

Q: What Interim Tier 4 (iT4) technology options has Bobcat favored?

A: The emission standards for all tiers, including Interim Tier 4, vary by the rated horsepower of an engine. Therefore IT4 compliancy deadlines and emission standards differ when a broad range of engine horsepower ratings are being considered. Cooled exhaust gas recirculation (CEGR) is a technology that has been already used in some models that have been Tier 3 or iT4 compliant for quite some time. Models that don’t have iT4 compliancy deadlines until 2012 will favor one or a combination of technologies available such as CEGR, diesel particulate filters (DPF), diesel oxidation catalysts (DOC) or selective catalytic reduction systems (SCR).

Q: Will Bobcat machines with Interim Tier 4 engines be more expensive?

A: Bobcat products such as the MT52 mini track loader, the S70 skid-steer loader, CT122 compact tractor, 418 and 324 mini-excavators and diesel powered utility vehicles (6 models) have already been TIER 4 compliant for quite some time. These products had very minor increases in price due to Tier 4. In some other cases, advancements needed in engines and other systems external to the engine for IT4 will add expense. However these technologies may also allow improvements to engine noise, sound levels, performance and diagnostic capabilities.

Q: When will Bobcat announce firm Interim Tier 4 plans?

A: We will be announcing our plans for Interim Tier 4 early 2012. We are being very diligent in exploring which technologies will be best for our customers in the long run, and we will stand behind those technologies.