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Verified Technologies for SmartWay and Clean Diesel

Caterpillar Technology—Emissions Upgrade Group (model 3406)

This retrofit technology is included on EPA's Verified Technologies List for Clean Diesel.

On this page:

Technology specifications

Engine Model/Application Caterpillar model 3406 diesel engines for nonroad applications, model years from 1973 to 1995 with mechanical direct fuel injection
Retrofit Fuel, Max Sulfur 15 parts per million (ppm)
Reduction in particulate matter (PM) 0.54g/kW-hr (Nonroad Tier 1 Level  1)
Reduction in nitrogen oxide (NOx) 9.2g/kW-hr (Nonroad Tier 1 Level  1)
Reduction in hydrocarbons (HC) 1.3g/kW-hr (Nonroad Tier 1 Level  1)
Reduction in carbon monoxide (CO) 11.4g/kW-hr (Nonroad Tier 1 Level  1)
Reduction in carbon monoxide (CO2) n/a 2

1  For nonroad engines 130 kW - 450 kW; The Diesel Emissions Quantifier (DEQ) may be used to estimate reductions from Tier 0 (or unregulated) to Tier 1 levels.

The CO2 level of reduction was found to be statistically insignificant at this time.

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Criteria to achieve emission reductions

This technology is approved for CAT 3406 engines between 150 and 450 kW, originally manufactured between 1973 and 1995 model years (see Attachment A for detailed list). The following criteria must be met in order for appropriately retrofitted engines to achieve the aforementioned emission reductions:

  1. The CAT 3406 EUG includes the components necessary to upgrade Caterpillar model 3406 diesel engines from 1973-1995, 150-450 kW to achieve US EPA Nonroad Tier 1 emissions levels. The primary components are the turbocharger, fuel pump/governor, fuel injection nozzles, pistons/rings/liners, and jacket water aftercooler.
  2. Prior to installation, the Caterpillar dealer must determine eligibility of the 3406 EUG by confirming the engine serial number with the engine arrangement and machine model as listed in Attachment A of this letter.
  3. The servicing dealer must follow specific installation instructions approved by Caterpillar and validate that the upgraded engine has the necessary Tier 1 components installed and has been tested to ensure the proper fuel delivery, power, torque and speed. The dealer must submit a validation form to Caterpillar to receive a label for the upgraded engine. 
  4. Caterpillar will confirm the engine upgrade with the validation submitted by the dealer and issue an engine label which must be installed by the dealer. 
  5. For replacement engine upgrades, Caterpillar must comply with the provisions in accordance with 40 CFR 1068.240 for replacement engines. 
  6. The engine must be operated on ultra-low sulfur diesel fuel (ULSD) of 15 ppm or less.

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Verification Letter from EPA

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