New Stage IV Wheel Loaders from Doosan: DL300-5, DL350-5 & DL420-5

Doosan Construction Equipment has launched the company’s new high performance ‘DL-5’ generation Stage IV compliant wheel loaders, the new DL300-5, DL350-5 and DL420-5 models, replacing the successful DL300-3, DL350-3 and DL420-3 Stage IIIB loaders launched in 2012. Providing another leap forward in wheel loader design represented by new external styling, the DL-5 range offers increased productivity and fuel economy, with features such as a new high comfort cab, powerful Scania Stage IV engines, smooth and responsive hydraulics, a ZF powertrain, axle cooling and auxiliary hydraulic connections. As in the previous DL-3 range, most of these features are standard on the new DL-5 wheel loaders unlike other machines on the market where they are options and many have been developed to optimise fuel efficiency.

The DL300-5 and DL350-5 wheel loaders are powered by the Scania DC09 5-cylinder diesel engine, with an output of 202 kW (271 HP) of power at 1800 rpm. The DL420-5 is powered by the Scania DC13 6-cylinder engine producing 254 kW (345 HP) of power at 1800 rpm. Providing generous torque at low rpm, up to a 10% reduction in fuel consumption and excellent response, the Scania engines meet Stage IV emission regulations without the need of a diesel particulate filter (DPF), through the use of cooled exhaust gas recirculation (EGR) and selective catalyst reduction (SCR) after-treatment technologies.

CoreTMS Fleet Management System as Standard
The DL300-5, DL350-5 and DL420-5 are factory-installed with the new CoreTMS state-of-art wireless fleet monitoring system, a feature not previously available as standard on Doosan wheel loaders and now incorporated in all new DL-5 generation machines. The new CoreTMS system is a tool designed specifically for the Doosan range, providing comprehensive information about machine performance in a dual mode (satellite, Mobile network).

The CoreTMS system offers a web-based fleet and asset management solution which is very useful for managing the performance and security of machines and promoting preventative maintenance. The system can support multiple Doosan machines in different locations, helping customers to monitor machine utilisation rates to assess that the right mix of machines is being used; it can also guide drivers to help them to operate equipment with higher efficiency and to locate replacement machines in the event of maintenance work or breakdowns, all under the umbrella of vigorous anti-theft and theft recovery protection systems.

New High Comfort Cab
The new cab demonstrates how Doosan has placed operator comfort at the very centre of its design priorities. Offering generous headroom and an ultra-comfortable, fully adjustable, heated Grammer air suspension seat, the DL-5 cab features a new steering column design giving more clearance for the operator’s legs and knees. The steering wheel can also be tilted and moved telescopically to match the operator’s preferred position.

The increased space, better visibility and plentiful storage space in the new cab allows operators to work for hours without fatigue or discomfort. Meeting ROPS/FOPS regulations, the cab also offers a wide emergency exit (located on the right hand side) to provide fast and easy evacuation in critical situations.

The 5.7 inch full colour LCD panel is suitable for day and night work. The user-friendly monitor has two customisable screen displays to suit the operator’s preference, giving a full readout of machine settings and maintenance data. The rear-view camera greatly enhances visibility and safety. The screen in the cab shows the operator what the camera sees and includes several lines to help judge distances; it also has other functions, including light intensity control, viewing angle control, language setting and power on/off setting.

On the control panel, all the switches are clearly arranged and within easy reach of the operator. Rocker type switches have been replaced by a multi-selection touch pad. Accurate and smooth joystick controls provide further comfort and operators can save time and reduce the number of operations with the ‘Boom Kick-out’ and ‘Return-to-Dig’ systems. These functions are operated electronically from inside the cab.

The cab air is filtered twice to eliminate all particles larger than 2 microns in size and the fully automatic climate control system adjusts the air temperature and fan speed to maintain the ideal climate setting for the operator.

ZF 5-gear Transmission
The ZF 5-gear transmission transfers the power from the engine to the wheels and contributes significantly to the overall reduction in fuel consumption. Engine speed variation is less thanks to smaller gear steps, and lower engine speed throughout the whole drive range reduces fuel consumption. Thanks to higher shift quality, noise levels are lower while driving performance and productivity have been increased.

All the new generation Doosan wheel loaders are equipped with a Torque-converter-lock-up (TCLU) system which, when activated, is switched on automatically. The lock-up provides a direct drive between the engine and transmission, enabling 100% torque delivery without any loss from 2nd gear up to the top 5th gear. This makes the TCLU more efficient, giving faster acceleration on flat ground (10%) and higher climbing ability (up to 20%), together with around up to 15% fuel savings in daily operation. This contrasts with many of the drive systems on other machines, where the TCLU is engaged only in highest gear.

The ICCO (Intelligent-clutch-cut-off) system allows the transmission output torque to be cut off according to the angle of the brake pedal, preventing unnecessary power use during braking, which in turn reduces brake wear and heat generation, while extending the oil change interval and promoting better fuel economy.

The outboard disc brakes enable easy servicing without dismounting the axles. The parking brake switch now includes a safety unlock trigger. When the engine is turned off, this brake is automatically engaged and not released when the engine is started.

The ZF Type II limited slip differential (LSD) axles at the front and rear automatically ensure maximum traction and easy driving over soft and muddy ground with no need for a manual differential lock. They also reduce the risk of skidding and prevent excessive tyre wear. There is an optional hydraulic differential-lock (HDL) axle for the new loaders that, compared to the LSD axle, provides further protection of the drive system components, including tyre wear reduction and produces 100% tractive effort when necessary, contributing to further fuel savings.

Optional on the DL300-5, DL350-5 and DL420-5 on the front and rear axles is the oil cooler system, a new feature providing higher axle oil cooling capacity for demanding applications, such as long-distance load and carry work in high ambient temperature conditions.

Load-sensing Hydraulic Pumps
All new generation Doosan wheel loaders have a load sensing hydraulic pumping system, whereby the variable axial piston pump generates the flow upon demand in the amount necessary to perform the work. This also gives better traction for penetrating into the stockpile, as less force is necessary to operate the bucket in many situations. Load sensing hydraulics also minimise loss in the hydraulic circuit during a carrying operation in which the loader is usually running, which is an essential technology for wheel loaders.

In response to customer feedback, the load-sensing system has been designed so that the bucket has higher priority when the boom and the bucket operate at the same time and there is limited force available.

Joystick control on the new wheel loaders is designed to easily combine several movements at the same time. As an option, 3-lever fingertip lever control can be provided for smooth and near-effortless control. Both of these controls use electrohydraulic piloting.

The machines have a Boom Kick-out function as standard, which is useful when working in confined spaces or when repeating similar operations in specific work ranges (for example, when a certain dump height must be reached every day). The same system is used to set the bucket automatically to the Return-to-Dig position.

The LIS (Load Isolation System), often called ‘Ride Control’, provides the operator with a smoother ride over rough terrain and enables a more comfortable ride at higher speeds. The benefits are reduced cycle times, higher productivity and better fuel efficiency while performing load and carry applications. LIS also contributes to longer frame and machine life.

The new loaders also offer a ‘third function’ to power a hydraulic system on a work tool, allowing greater machine versatility in a number of applications. The third function valve’s capacity has been increased significantly to at least 250 l/min discharge compared to 120 l/min in the previous DL-3 models.

Additional Fuel Savings
On the DL420-5 and larger loaders, the engine Auto Idle system when activated saves on fuel costs by lowering the idle level from 950 to 750 rpm – when the operator does not give any input to the steering wheel, arm and bucket for more than 10 seconds (ideal for applications where there is a lot of waiting time such as truck loading). In all DL-5 loaders, the Engine Auto Shut Off shuts down the machine after it has been idling for a specified amount of time (3-60 minutes, configurable by the operator via the control panel). This feature saves on fuel and reduces operating costs.

The exhaust and after-treatment system for the engine is installed on the left-hand side of the machine, whilst the components for maintenance are grouped on the right-hand side. All the daily checking of gauges can take place from ground level to ensure it is a quick and safe process. Doosan has also installed an automatic greasing system as standard to reduce working time and increase operating comfort. To facilitate access and mobility on the machine, multiple hand-rails ensure that the operator always has a firm support to hold on to.

The cooling compartment is separated from the engine compartment to prevent warm and dusty air from entering and to allow better control of the air intake. An automatically reversing fan is a standard feature - the radiator fan is hydraulically driven and controlled by an ECU. Changing the fan direction for cleaning the radiator can be done manually from the cab, without having to switch off the engine. Fan reverse intervals (30 minutes to 2 hours) can be set via the menu.

The front structure is more rugged, with much greater rigidity and strength. The Z-bar geometry is designed for heavy lifting with few moving parts. This design also helps stabilise the loader, enables very rapid bucket movements and keeps the bucket at the right angle position at all times. All DL-5 models are available with a High-lift configuration, with a longer arm enabling higher dumping of materials.

With bucket capacities ranging from 3.0 to 4.5 m3, the new Doosan DL300-5, DL350-5 and DL420-5 wheel loaders are 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.