Specialist focus: Plant: Excavators move with the times

While emissions legislation has resulted in perhaps the greatest surge in new versions of tracked excavators to hit the market in recent times, many firms have chosen to go beyond just fitting cleaner engines.

JCB, Case and Hitachi are among the firms that have bucked the trend to stay with six-cylinder engines, instead choosing similar capacity four-cylinder turbo motors using high-pressure common rail fuel injection.

Korean maker Doosan has been gradually rolling out its DX models to replace the now ageing Solar models.

The DX line-up features a 'ground-up' design with the company's latest Stage IIIa engines with advanced, electronically controlled common rail, direct injection fuel systems, four valves per cylinder and a new combustion system - all providing lower emissions with improved fuel economy, says the firm.

The DX series features extended service intervals, in-cab adjustment of oil flow for attachments and a facility to activate a four-digit Pin Code before the engine can be started.

In the compact sector, Doosan has just started to add zero tail-swing or short-radius machines to its range.

The DX35z replaces the Solar 35, and will run alongside the smaller Solar 30, as the firm believes this segment is still predominantly one that prefers 'conventional' mini excavators.

New Holland's E215LC ME is a standard excavator that can be adapted to use a third boom and provide reach to a depth of more than 15m.

The firm also offers the E150 Bladerunner, which blends the upper structure of the 13t E135 with the undercarriage of a 20t machine. The result is an excavator-dozer, says the firm.

Environmentally friendly

Komatsu has been steadily rolling out its revised Dash-8 excavators, and the latest machine - shown recently at Hillhead - is the 80t operating weight PC800LC-8.

Designed to be more environmentally friendly and offer reduced operation costs, the PC800 packs a 363kW punch through its SAA6D140E-5 engine. An electronically controlled variable speed fan drive reduces both fuel consumption and environmental noise, says the firm.

The PC800LC-8 comes with Komtrax machine monitoring as standard, allowing the exact location of the excavator to be remotely monitored at all times.

Volvo has been rolling out its C-series excavators and unveiled the 24t EC240C at SED.

The new range offers Stage IIIa compliant Volvo engines that are more powerful than those in the outgoing comparable B-series models, and such performance has been matched to intelligent hydraulic systems and incorporated into a machine design that now features a more rugged undercarriage and upper structure, and a new operator's cab.

The heart of the C-series is an engine design featuring Volvo Advanced Combustion (V-ACT). Said to be impossible to stall as the onboard computer balances maximum available power to hydraulic output, thus preventing the engine from becoming overloaded, the V-ACT engine offers high torque at low revs, delivering high fuel efficiency, says Volvo.

Among the C-series excavator options is CareTrack GPS monitoring, which allows users - from their computers - to track machine location, fuel usage, hours of operation and set machine usage limits, a feature that could appeal to the plant hire industry.

Liebherr claims improvements in performance, reliability, efficiency and comfort for its 32t R934C, which is powered by a 149kW diesel engine. The excavator features Liebherr's Regeneration Plus function, which includes safety check valves and pressure-free boom lowering that contributes towards faster work cycles. A larger cab with climate control also features.

In the 14t class, Liebherr's R313 Litronic excavator now combines Deutz power with the firm's own engine and hydraulic system management - developed in conjunction with an in-cab display allowing operational data, along with engine and hydraulic system performance, to be reviewed and amended.

Greater efficiency

Hyundai has revamped its Dash 7 models. The new Dash 7A machines come with a host of improvements, including common-rail fuel injection driven by Stage IIIa legislation, but offering greater efficiency, a multi-function joystick and a revised information and control centre.

For the operator, the new models get a new multi-function joystick, which means that extra functions for attachments such as tilt rotators, hydraulic hammers or concrete crushers, can now be managed from the control lever.

The control-panel display has also been completely redesigned. The operating information is now displayed graphically and is more quickly and easily understood.

This user-driven menu now offers additional information for servicing and security, with the latter requiring a password, to prevent unauthorised use of the machine.

Caterpillar offers a dual horsepower setting on several of its excavators, as a result of shifting to Acert engine technology used on larger models.

These power and economy modes are accessed through an all-new in-cab colour monitor, which fettles pump pressure and engine revs to give a useful selection of working speeds, force and controllability.

For those who frequently switch attachments and alter hydraulic flow rates, the monitor has a short-cut function that takes the operator directly to the attachment oil flow values, where 10 preset flow values can be used to closely match work tools.

The monitor, with more colour and contrast, is said to be much easier to view with a casual glance, and the screen is also video-ready, making the installation of a rear-view camera a plug-and-play experience.

Hitachi's 18t ZX160-3 gets a revamped CRES cab sporting a revised, right-hand side console with an integrated multi-function monitor.

The widescreen LCD colour monitor provides easy access to work modes, attachment settings, maintenance information and fuel consumption - all at the touch of a button. It also requires a four-digit pin number to be entered into the system before the machine can be started.

It combines with the Isuzu engine and HIOS IIIhydraulic system to create more speed and performance from the boom and arm, assisted with a boosting system that puts greater oil flow to the cylinders.

A regenerative system, it provides a 20% increase to arm roll-in speed and a 15% increase in arm swing speed when making combined boom and arm movements.

Arm roll-in speed is improved by sending excess oil pressure from the boom's cylinder rod-side to the arm cylinder's piston-side via a regenerative valve, to increase the oil-flow rate.

With a revised engine and hydraulic system, Hitachi reckons the ZX250-3 has the potential for up to 11% more productivity, while saving up to 15% on fuel costs.

Tracked excavators

JCB has padded out its JS tracked excavator portfolio even further with a new series of JS Auto models. Depending on the model, the new machines feature a power increase of up to 25%, a torque rise of up to 27% and the potential for fuel savings of up 12%.

The latest models include the JS160/180 Auto, JS190 Auto, JS 200/210/220/235 Auto, JZ235/255 Auto and the JS240/260 Auto tracked models.

Isuzu engines provide the power, and are fitted with an isochronous engine governor system, which reacts to hydraulic requirements when working - this automatically adjusts engine power according to load. An electronically-controlled engine cooling fan and electronic oil level monitoring system add to the convenience.

In the cab, a high-backed seat, cargo shelf and stowage net add to the comfort levels, as does an automated climate control system - providing such optional equipment is specified.

Case has recently swapped a six-cylinder engine in its 21-tonner in favour of a high-efficiency four-pot as the firm chases lower fuel consumption and increased production as a by-product of meeting Stage IIIa emissions legislation.

The CX210B features simplified operating modes, revised joystick levers and advanced electronics for improved matching of machine components. An all-new cab design is said to result in a significantly quieter working environment both inside and outside the cab, says the firm.

In the compact sector, Austrian maker Neuson has extended its line-up with yet another model in its Z-series.

Based on the successes achieved with its existing three Z-series short-radius mini excavators, Neuson has extended the range with a smaller model, the 2.8t 28z3.

The increasing popularity of short radius excavators has meant the firm's conventional 3t 3003 model will now be dropped in favour of the new 28z3. Shod on 300mm rubber tracks, the 2.8t excavator features a side-mounted, three-cylinder Yanmar engine, fully glazed cab and can be equipped with hammer piping.

An all-new boom and arm has been developed for the machine and affords hydraulic hose routing through the kingpost.

Sweeping curves

Japanese maker Hanix is gradually phasing out the boxy styling of its current mini excavator range in favour of smoother lines and sweeping curves, and the H55DR is the first example of such progress.

Still at prototype stage, the machine is the first in Hanix's planned D-series upgrades, which include features such as auto idle, auto engine shut-off if left idle for five minutes, and the ability to fit air conditioning and an immobiliser as extra cost options.

The D-series will also provide a five-sided hexagonal cab design, which allows the door to be opened through 190° and keeps the door frame protected within the machine's upper structure, when opened.

Bobcat has also added to its mini excavator range with the 425, which increases the firm's zero tail-swing line-up, along with an enhanced version of its 323 model and an all-new version, the 321. The zero tail-swing, 2.6t 425 model is powered by a Kubota diesel engine and includes load-sensing hydraulics for fine control. The smaller 323 and 321 models are also powered by Kubota engines, but include a new hydraulic pump, revised travel motors and a newly designed slew ring.

For innovation in compact excavators, French firm Mecalac clearly leads the way - its latest prototype, which blends crawler excavator and skid steer loader into one machine, is just one key example.

At Bauma in April this year, the firm previewed its innovative 8MCR prototype, which combines mini excavator and skid steer loader in one package.

It remains an interesting concept, and is one that sees the rubber-tracked machine reach speeds of up to 11kp/h. The firm says that if pre-production testing goes according to plan, commercial models should roll off the Annecy production line during 2008.

The firm says the 8MCR is currently the only excavator in the world capable of reaching 11kp/h, accepting that if it is to successfully compete with skid steer loaders throughout Europe, it has to be nimble and agile, in addition to digging holes.

Selecting the 'excavator' mode sees the joystick levers work conventionally, allowing the operator to use the machine as a mini excavator.

Opting to select the 'loader' mode transforms the control system into that of a compact loader, and authorises the hydrostatic transmission to reach the higher operating speeds.