Interim Tier 4 Technology Strategy

Doosan construction equipment with engines of 75 horsepower or greater will comply with iT4 regulations in either 2011 or 2012. This entails a continued reduction in nitrogen oxides (NOX) and particulate matter (PM).

In order to meet the iT4 regulations, Doosan is utilizing several technologies for its excavators, wheel loaders and articulated dump trucks which provide the best solution based on machine utilization characteristics.


Doosan crawler excavators and wheel excavators, from the DX140LC to the DX530LC and the DX140W to the DX190W will incorporate a three-fold systems approach*:

  • Cooled Exhaust Gas Recirculation (CEGR)
  • A Diesel Oxidation Catalyst (DOC)
  • A Diesel Particulate Filter (DPF)

CEGR works well when the engine runs at a rated engine RPM versus varied engine RPMs. Since Doosan excavators typically operate at a full-rated RPM, the engine operates at a consistent combustion temperature and reduces NOx. The DOC and DPF act as after-treatments to reduce PM.

The DX190W, DX235LCR and DX700LC excavators and the DX225LL and DX300LL log loaders are currently Tier 3 compliant. They will comply with T4 regulations in 2014 or 2015.*


Learn more about Interim Tier 4 and Tier 4 technologies

Wheel Loaders

Doosan wheel loaders will use the following systems to comply with iT4 regulations:

  • Models between DL200 and DL250 (75 to 175 hp) incorporate CEGR, a DOC and a DPF
  • Models DL300 through DL550 (175 to 300 hp) use Selective Catalytic Reduction

Engines which utilize Selective Catalytic Reduction (SCR) systems are optimized to reduce PM internally.  This optimizaiton offers increased fuel efficiency and savings which benefit larger displacement engines.  Since the fuel savings is less significant in smaller displacement engines, a CEGR, DOC and DPF is used.

Another factor is the limited space for additional components in wheel loaders. The DOC/DPF canister size increases on larger horsepower engines. To maintain acceptable service access and avoid changing the exterior profile of the engine compartment, SCR systems were selected for larger models.



Learn more about Interim Tier 4 and Tier 4 technologies

Articulated Dump Trucks

Doosan articulated dump truck's engines will utilize SCR to comply with iT4 emission regulations.  SCR technology is suitable for machines requiring high torque or speed.  SCR is also ideal since the engine RPM varies as ADTs travel and wait to be loaded.



Learn more about Interim Tier 4 and Tier 4 technologies.



* These models maintain Tier 3 compliance utilizing the EPA's equipment manufacture flexibility program.