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Tier 4

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.

Chart 1 explains how harmful emissions such as NOx and PM are reduced through each emission tier.

Chart 1

All Tiers - Compact Equipment
Engine Horsepower 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Less than 25.5 Tier 1 Tier 2 Tier 4
25.5 - 75 Tier 1 Tier 2 Interim Tier 4 Tier 4
75.1 - 175 Tier 1 Tier 2 Tier 3 Interim Tier 4 Tier 4

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.

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 in chart 1). 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 75.1 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.

Chart 2

Engine Size Additional Technologies needed for iT4 compliance Additional Technologies needed for T4 compliance
< 25.5 hp No No
25.5 - 75.1 hp No Yes, to be applied November 2013-2014*
> 75.1 - 175 hp Yes, applided during 2012* Yes, to be applided in 2015*

*Chart 2 represents a general application of emission technologies to Bobcat machines. Always check with your Bobcat Dealer to confirm the emission tier compliancy and emission technologies used for a given machine.

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. (See chart 2 for more detail).

For compact equipment, 2012 was the first time emission regulations became stringent enough to require additional technologies for compliance.

In 2012, the Federal Interim Tier 4 (iT4) emission regulations became effective for compact equipment using > 75.1 horsepower (hp) engines.

The Bobcat machines affected were the seven compact loader models offered in the 700 and 800 platforms, which represented 15% of Bobcat’s total product offering. The remaining 85% of Bobcat machines were unaffected by emission regulations in 2012.

To achieve iT4 compliance with 700 and 800 platform loaders, Bobcat incorporated an Electronic Control Unit (ECU), High Pressure Common Rail Fuel System (HPCR), Diesel Oxidation Catalyst (DOC), and a Diesel Particulate Filter (DPF). See figure for details of each technology.

The need for additional emission technologies will be required two more times. For Bobcat, the first will happen over a 15-month period, starting in November of 2013, when Bobcat machines using engines with 25.5 – 75.1 hp engines become Tier 4 (T4) compliant. This applies to Bobcat 400, 500 and 600 platform loaders, ToolcatTM utility work machines, and nearly every Bobcat compact excavator model*.

The next phase will happen in 2015 when compact equipment using > 75.1 (hp) engines are required to become T4 compliant (Bobcat 700 and 800 platform loaders). This will be the second time compact equipment in this size class needs additional technologies to meet emissions regulations.

*Excludes Bobcat 418 and 324 Mini Excavator models. These machines are already T4 compliant as a result of a different emission tier schedule due to their smaller engines. See chart 1 for engines < 25.5 hp for details.