(WEST FARGO, N.D. – August 2014) Two new Tier 4-compliant Doosan excavators are now available in the United States and Canada – the DX300LC-5 and DX350LC-5 – featuring improvements in fuel efficiency, productivity and durability. Replacing the DX300LC-3 and DX350LC-3 models respectively, the new Doosan crawler excavators have new engine modifications and aftertreatment technologies to meet Tier 4 emissions regulations.
Tier 4 engine configuration
Doosan 271-horsepower DX300LC-5 and 318-horsepower DX350LC-5 excavators are powered by Scania diesel engines that have been configured with a high-pressure common-rail (HPCR) fuel delivery system as well as cooled exhaust gas recirculation (CEGR). Doosan also added a mass airflow (MAF) sensor and exhaust brake to the engine to help meet Tier 4 emission standards. The mass airflow sensor allows the electronic control unit (ECU) to improve the management of airflow provided by the variable geometry turbocharger (VGT), and to optimize fuel delivery to the combustion chamber based on 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, and improves machine performance in the Standard and Economy power modes while saving fuel.
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 Tier 4 compliant Doosan excavators combine selective catalyst reduction (SCR) with a diesel oxidation catalyst (DOC) to reduce engine emission levels. Diesel exhaust fluid (DEF) is used with SCR technology and stored in a DEF tank near the front-left corner (opposite of the operator station) of Doosan crawler excavators. The DOC transforms particulate matter (PM) emissions into harmless water and carbon dioxide. DEF is injected into the exhaust system to transform the nitrogen oxides (NOx) produced during combustion into water and nitrogen.
Available for the DX350LC-5, D-ECOPOWER optimizes hydraulic system output with engine horsepower, improving machine efficiency, productivity and fuel consumption, as well as refining machine control and enhancing operator comfort. A pressure controlled pump, closed center main control valve and various sensors in the excavator electronically detect and control the precise amount of hydraulic oil required to perform a task.
Four power modes
Similar to previous Doosan excavators, operators can choose from four power modes for more control to better balance fuel consumption and machine power to the working conditions. Power modes include the following:
“¢ Power+ mode: delivers the fastest workgroup speeds for loading trucks, top digging performance and extra power for digging in hard ground
“¢ Power mode: provides exceptional power and performance for tough digging conditions and truck loading tasks
“¢ Standard power mode: balances the excavator’s fuel consumption in everyday digging, grading and lifting tasks
“¢ Economy mode: reduces fuel consumption for low-demand applications, slows down machine movement for conditions that require extra precision
To further match Doosan excavators to the application at hand, operators can choose from four work modes – Digging, Breaker, Shear and Lifting – to maximize efficiency and fuel economy in specific applications. Operators can configure the work mode by adjusting a dial switch on the right-hand console. A work mode icon displays on the monitor after the operator presses the mode button.
New Tier 4 compliant Doosan excavators feature improved fuel efficiency to help owners reduce operating costs. For example, a Tier 4-compliant DX350LC-5 excavator has a 10 percent fuel savings from the equivalent Tier 3 model. For further fuel savings, auto shutdown helps owners save fuel during non-working conditions. When enabled, the feature will shut down the excavator’s engine after a preset idle time. For example, the operator can configure the idle time from 3 to 60 minutes. For operators in California, auto shutdown helps meet the state’s regulations of idling for only five minutes for off-highway machines.
An improved 7-inch LCD display panel allows operators to continue monitoring the excavator parameters while viewing the rearview and/or side view camera image. Critical machine data appears next to the camera view. With an optional side camera, a split screen allows both camera displays to be viewed at once. New additions to the monitor include the DEF gauge and fuel efficiency.
New machine updates
In addition to auto shutdown and LCD display panel updates, the new Doosan DX300LC-5 and DX350LC-5 crawler excavators have the following updates:
“¢ Improved serviceability for uptime protection
“¢ Auto belt tensioner: fan and air conditioning
“¢ Anti-skid plates for better traction on steps and other walking surfaces
“¢ Enhanced access to the emergency engine stop
“¢ Battery and alternator upgrades to minimize downtime
“¢ For greater operator comfort, the floor pedal angle has been improved by 10 degrees.
Some factory-installed options for the new DX300LC-5 and DX350LC-5 crawler excavators include the following:
“¢ Additional work lamps
“¢ Cab guarding for special applications
“¢ Diesel-powered coolant heater for cold starts
“¢ Rotate circuit hydraulic piping
“¢ Straight travel pedal, which allows the operator to travel in a straight line more easily
“¢ Two-way auxiliary hydraulic pedal (in addition to joystick control)
In an effort to minimize downtime, Doosan excavators have standard features that ensure their durability, even when operating in harsh conditions. These features include a robust and reliable track tensioning system. Improvements made during the launch of the dash-3 models, such as larger bushings in track rollers and thicker sprocket teeth, are evident in the dash-5 models. Also carried over from dash-3 models are added reinforcement plates and increased plate thickness to the excavators’ boom and arm.