DOOSAN continues to extend and enhance its range of large wheel loaders with the launch of the new DL420, which succeeds and replaces the DL400. Also newly launched by the company is the DX380LC crawler excavator, designed and built to give optimum value.

After the addition of the DL420, the Doosan range of articulated wheel loaders now includes eight models with bucket capacities from 1.5 to 5 cu m. Key features offered by the DL420 include more productivity at lower cost, reliability, comfort and ease of maintenance.
“With a bucket capacity of 4 cu m, the DL420 is designed to offer exceptional performance in terms of ease of handling, power, serviceability and durability. It is intended to meet a wide range of material-handling needs from loading and transporting granular material (such as sand and gravel), to industrial, mining and quarrying applications,” says a spokesman for Doosan.
The 22.3-tonne DL420 loader is powered by a 10.8-litre, six-cylinder turbocharged Cummins QSM11 electronically-controlled engine with a high-pressure unit injector system and a state-of-the-art combustion system. Emissions are well below Phase Three regulatory limits and fuel consumption is about seven per cent less when compared to the DL400. The engine develops 284 hp at 2,000 rpm and offers a maximum torque of 148 kgm at 1,400 rpm, for optimal traction and breakout force in loading-transport-handling applications.
“Breakout force is among the highest in its category at 210 kN, an important feature for a machine of this Z kinematic class, providing a higher stripping force when working in the hardest materials,” the spokesman points out.
Two working modes (standard and economical) are available to optimise the consumption/productivity ratio and adapt the loader to the work at hand. There are four travel speed ranges forwards, with maximum speeds of 6.5, 12.4, 18.4, and 38 kmph, and three travel speed ranges backwards, with maximum speeds of 6.5, 12.4 and 18.4 kmph. Thanks to the powerful Cummins engine, the DL420 offers fast acceleration and is able to reach 90 per cent of maximum speed in 2.3 seconds. The larger engine also is designed to provide increased durability and a longer service life.
The DL420 offers a static tipping load with bucket of 18.9 tonnes (at maximum reach with a straight frame) and a height at bucket pivot point of 4.35 m. Equipped with a pin-on bucket with teeth and tipped forward at 45 degrees, the dump height is 2.96 m and the dump reach is 1.4 m. The turning radius at bucket edge is 6.99 m at a maximum steering angle of 40 degrees.
Like all other Doosan wheeled loaders, the DL420 uses a Powershift ZF transmission with limited slip differentials (ZF). The primary brakes are hydraulically-controlled, multi-disc wet brakes.
Special attention has been given to the design and construction of the DL420. In order to ensure a long service life of the main structural components, including the chassis, lift arms and articulations, Doosan uses finite element methodology and state-of-the-art computer-aided design techniques. Using computerised modelling, the machines are subjected to intensive laboratory and field tests in which extreme conditions are simulated and tested.
Operator comfort and convenience were given high priority when the DL420 was designed, says the spokesman. “Improved visibility, heating and air-conditioning, more space, a very comfortable seat, and ample storage space are all features which enable operators to work for more hours with less fatigue. The noise level in the cab is a comfortable 71.2 dB(A) while the external sound level is 104.7 LwA.”
New features contributing to operator convenience include an integrated monitoring system, vehicle control unit (VCU) and an optional electric steering system. The integrated LCD panel displays information about the loader, engine and transmission, including the service intervals for each filter and the engine oil. The transmission can be tuned by the operator without the assistance of a mechanic. For its part, the VCU optimises performance by controlling engine, transmission and hydraulic system variables.
Other features contributing to operator comfort and convenience are a third hydraulic control valve to use the most complex attachments and anti-pitch control. Available as an option is a system using a single lever for the control of travel functions and front-mounted attachments.
“The Doosan DL420 wheel loader is designed to be economical both from the standpoints of use and maintenance. To reduce fuel consumption and noise, the variable fan speed is controlled by a thermostat. The fan is reversible and tilts in order to facilitate maintenance in dusty environments. There are also large covers for service access from the ground. Intervals between oil changes and filter replacement have been lengthened, as for the other Doosan loaders. Transmission status is easily verified and various adjustments such as compensation for disc wear are done automatically with no disassembly required,” he adds.

Crawler excavator
Meanwhile, the new DX380LC crawler excavator provides increased productivity with improved fuel economy, enhanced visibility and comfort for the operator, greater reliability and durability as well as increased uptime by reducing maintenance time and cost.
“The range of applications for the DX380LC runs from heavy construction and excavation to development of construction sites, construction and renovation of highways and other large works of civil engineering as well as mining and quarrying,” explains the spokesman.
It is powered by a six-cylinder “common rail” Doosan DL08 turbocharged diesel engine providing 275 hp at a maximum governed speed of 1,900 rpm. The e-EPOS electronic control system provides optimum power at reduced fuel consumption in all working operations. Emission levels are well below the values required for Phase Three.
The long carriage (LC) design, based on the larger DX420LC model, offers exceptional stability and safety in all kinds of operating circumstances, including heavy material-shifting and lifting applications.
The DX380LC has an operating weight of 37.9 tonnes. Like the DX340LC, there are three arms of varying length available for the DX380LC. Equipped with the longest 3,950-mm arm, the DX380LC offers a maximum digging depth of 8,200 mm; the dump height is 7,750 mm; and the maximum digging reach is 11,930 mm.
The arm and bucket cylinders are sized to provide enhanced excavating force. Digging force over the bucket is 21.7 tonnes, while that over the arm is 17.3 tonnes. “Use of power boost increases both forces by about five per cent, the highest forces of any excavator in this class,” he adds.
Thanks to the high engine power and the high swing torque (12,000 kgfm), the DX380LC can work efficiently on slopes. There are two travel speed ranges with a maximum speed in low range of 2.9 kmph and a maximum speed of 4.8 kmph in high range. The maximum swing speed is 9.3 rpm and the drawbar pull is 31.5 tonnes.
Like all heavy Doosan excavators, the DX380LC has as standard the ‘auto idle’ feature, which reduces fuel consumption and noise and creates a more comfortable environment. Another important feature for reduced fuel consumption is the optional new “economy mode” whereby priority is given to minimal fuel consumption.
The DX380LC combines maximum productivity with the ability to carry out jobs with precision and fingertip control. The load-sensing piston pump and the closed centre valve enable exceptionally fine metering of hydraulic flow for smooth, precise control of machine functions, while reducing hydraulic noise. The boom and arm cylinders are cushioned to provide a smooth, end-of-stroke-operation.
The unit has a modern spacious operator cab, equipped with ergonomic controls and instrumentation. Options available to enhance convenience for the operator include a “Water In Fuel” (WIF) sensor as well as a rear view camera and 18-cm colour LCD monitor. The noise level at operator ear is 73 dB(A) while the noise level for bystanders is a very low 101 LwA.
The excavator uses many parts from the larger DX420LC model. These parts have been tested and verified in actual field conditions, thus ensuring increased reliability and less down time. Engine service intervals for the machine are at 500 hours.