Five new machines replace the previous interim Tier 4 (iT4) models and are powered by Scania diesel engines.

Doosan has introduced its first Tier 4-compliant wheel loaders — the DL300-5, DL350-5, DL420-5, DL450-5 and DL550-5 — with a horsepower range of 271 hp in the DL300-5 to 379 hp in the DL550-5. Improvements in fuel efficiency, operator comfort, serviceability, reliability and remote monitoring with Doosan Telematics are all features that make the new Doosan wheel loaders stand out from other brands.

Tier 4 solution
The five new Doosan wheel loader models replace the previous interim Tier 4 (iT4) models and are powered by Scania diesel engines. The engines are optimized for use with a high-pressure common-rail (HPCR) fuel delivery system and a cooled exhaust gas recirculation (CEGR) system. They utilize a diesel oxidation catalyst (DOC) to reduce particulate matter (PM) and selective catalyst reduction (SCR) aftertreatment to reduce nitrogen oxides (NOx) — the same technology used to achieve iT4 compliance in this size class. Additionally, the wheel loaders use a variety of aftertreatment systems as part of the Tier 4 compliance, such as diesel exhaust fluid (DEF), which is used with SCR technology and stored in a DEF tank.

Doosan added a mass airflow sensor and exhaust brake to its existing diesel technologies to help meet Tier 4 emission standards. The mass airflow sensor allows the electronic control unit (ECU) to improve the management of airflow from the variable geometry turbocharger (VGT), and to optimize fuel delivery to the combustion chamber based on engine air intake volume and rpm. The VGT is utilized to enhance boost pressure throughout a wide rpm range of the engine, resulting in improved fuel efficiency at lower rpms. This also generates higher torque levels and faster engine response even at low rpm. The exhaust brake helps to maintain consistent engine temperatures at lower engine speeds to improve operating efficiency. Consistent engine temperatures reduce harmful emission levels in the exhaust when the engine is running at lower rpms. Under normal operation, with high rpms, the exhaust brake is inactive.

New wheel loader features
New Doosan wheel loaders feature cab enhancements including an improved adjustable steering column to provide more leg room, ease of operation and more floor space. Also inside the cab, a new fuel consumption gauge informs operators how much fuel the machine is using in real time. Updates to the keypad on the dashboard make it easier for operators to review, adjust settings and to clean and maintain it. Overall, visibility within the cab and around the machine has been improved too.

All five new Doosan wheel loaders have an auto-shutdown system to help reduce fuel consumption when the machine is sitting idle. Operators can configure the idle time from 3 to 60 minutes. Rear LED lamps provide better visibility, especially when working on a jobsite at night. Limited slip differentials are also included and allow the machines to have more traction when working.

Doosan Infracore Construction Equipment America.

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