Doosan says it will use both Exhaust Gas Recirculation (EGR) and Selective Catalytic Reduction (SCR) to comply with the new Stage 3B emissions regulations. These impose a further 90 per cent reduction in the allowable level of particulate emissions and a 50 per cent cut in oxides of nitrogen (NOx).
The roll-out of the cleaner engines will begin in September with the first of a new generation of articulated dump trucks (ADTs) and they will also feature in a new generation of excavators and wheel loaders.
Doosan says EGR technology is more suited to on-site machines where the requirement is for multi-task capabilities and it will use the technology for its new wheel loaders below 130 kW and all the new wheeled and crawler excavators. These machines will have either Doosan or Isuzu engines fitted with a diesel particulate filter (DPF) and in some cases a diesel oxidation catalyst (DOC).
SCR technology will be used on the new ADTs and wheel loaders above 130 kW where high torque or speed is required. These machines will be powered by Scania engines and will require an additional tank to store the urea used in the catalytic process.
Doosan will introduce low-emission engines across America, Canada and Japan but despite the similarity of the EU’s Stage IIIB regulations and Tier 4 Interim in the US, European machine will only be certified to the EU standard.
Looking ahead to 2014, the company says to meet the EU’s even more stringent Stage 4 regulations, its machines will be fitted with engines featuring a combination of both DOC/DPF and SCR technology.