Excavator remains the key earthmoving tool

The excavator remains the key earthmoving tool, Mike Woof reports

The versatile hydraulic excavator has been at the heart of most earthmoving projects around the world for many years, a dominance that looks set to remain. Because of the importance to the construction sector of the excavator, manufacturers are keen to upgrade and improve their competing machines on an almost continuous basis. New technology proliferates in hydraulic excavators while firms are also focussing on increasing the range of tasks that can be handled by these highly adaptable machines.

Arguably one of the most notable introductions to the hydraulic excavator market in recent times has been the launch of 2300 Komatsu's hybrid machine, which is aimed at the 20tonne class. While other manufacturers have developed prototype hybrid machines, Komatsu is the first to go one step further and make its hybrid machine available as a full production unit. The PC200-8 Hybrid machine was first unveiled at the end of 2008 in Japan and was later introduced to the US and North American markets.

Developed primarily to reduce fuel consumption, the machine also has low exhaust emissions compared with conventional excavators, features that will suit the unit to use in certain markets. Demand has been particularly strong in China where fuel costs are high, resulting in a quicker payback time for this premium priced machine and over 200 units have been supplied to the country.

A number of units have also been supplied to the US, although the reduced emissions are more likely to prove the reason for acceptance in this particular market, particularly in California where emission regulations are much tighter.

Although the machine being unveiled at 688 Bauma is not homologated to meet European regulations, Komatsu is keen to highlight the benefits of this technology. And an EC compliant version will be available as soon as Komatsu believes the market will be ready for the machine. Given the rising price of diesel in Europe, the reduced running costs could well prove attractive and with operating experience of the unit from China to verify its reliability in service, it seems only a matter of time before the machine is available in the European market.

Key features of the PC200-8 Hybrid are its newly-developed electric swing motor, power generator motor, capacitor and diesel engine. The machine can use the kinetic energy from the swing braking phase to generate electricity that is sent through an inverter and then captured by the Komatsu Ultra Capacitor system. The captured electricity is then discharged to drive upper structure rotation and assist the engine.

Unlike hybrid road vehicles, construction machines have to deal with dynamic and frequent fluctuations in engine speed. The chemical reactions of batteries used in road vehicles would take too long to discharge electricity for construction applications and in this duty the capacitor is more efficient. It is worth noting that this novel Hybrid machine offers the same performance as a standard PC200LC-8. However in comparison tests with the standard model the hybrid system offers fuel savings of 25-40%, depending on the application.

There are also some rather more conventional new excavator launches from major manufacturers, including 695 Doosan, 236 Hyundai and 2394 Volvo. From Doosan comes the new 38tonne DX380LC crawler excavator, which is aimed at heavy construction and excavation, highway renovation and other major civil engineering projects. For stability, the machine has been equipped with the heavy-duty undercarriage of the firm's 42tonne class DX420LC model while this new exactor is offered with three boom assemblies. The longest measures 3.95m and allows a maximum digging depth of 8.2m, dump height of 7.75m and digging reach of 11.93m. A power boost function can increase digging force by 5%, while the DX380LC offers high engine power and features as standard an auto idle system to reduce fuel consumption and noise. Fuel consumption can be further reduced using optional economy mode.

Hyundai is now introducing its series 9 excavator line-up to the European market with its key launch being the 21tonne class R210LC-9 crawler model. The machine weighs in at 21.9tonnes and shares features with the 25tonne, 29tonne, 32tonne, 38tonne, 48tonne and 52tonne -9 Series models Hyundai will introduce in coming months. The R210LC-9 is powered by a 196 Cummins diesel rated at 113kW and which meets Tier 3/Stage IIIA exhaust and noise emissions legislation. Sophisticated hydraulics ensure precision working according to the firm, as well as allowing fast cycle times and high productivity across a range of earthmoving applications such as loading haul trucks or digging in hard ground. Hyundai has targeted economy as a key feature and the machine has several fuel saving systems, such as one-touch and auto-deceleration and a fan clutch system that increases the engine cooling fan speed on demand.

It is worth noting that the -9 Series machines are now well proven having already been released in Hyundai's Korean home market as well as in North America. A key feature of the new -9 Series from Hyundai is the new high visibility cab that has a multi-purpose dashboard, with a multi-function, 130mm colour LCD screen. The operator can also use the screen to select power modes, work modes, maintenance checks and diagnostic checks.

A novel features is Hyundai's sophisticated Hi-Mate GPS technology based remote management system. This offers machine tracking, tracing and monitoring capabilities around the clock and regardless of geographical location. Using the Hi-Mate system allows the owner to remotely diagnose equipment, check operating hours as well as fuel level, and pinpoint the exact position of the machine.

Meanwhile Volvo is offering new versions of its 36tonne and 46tonne class excavators that deliver more engine power combined with greater fuel economy. Engine output has been boosted by 11.6% and 4% for the EC360C and EC460C respectively while consumption has been reduced by 6-7%. Travel speeds have also boosted, along with maximum slew speed and overall these machines are said to cycle faster, operate more productively and burn less fuel than before across a range of tough earthmoving applications. Meanwhile the firm has also beefed up main structural components and claims that they offer greater durability along with lower maintenance needs and reduced downtime, significantly boosting the overall cost/tonne for the user.