Excavators: The efficiency challenge

By Helen Wright14 October 2011

Doosan’s new 32 tonne DX300LC-3 excavator was launched in September – the first in a new generation

Doosan’s new 32 tonne DX300LC-3 excavator was launched in September – the first in a new generation of Stage IIIB-compliant machines.

There has been a flurry of excavator launches so far this year, with a distinct emphasis on the 20 to 40 tonne weight range.
Most major manufacturers are showcasing their new Stage IIIB machines for Europe, but as well as compliance with emissions regulations, manufacturers are striving to create the most fuel efficient excavators on the market.
A trend for high performance hydraulics is emerging in the latest machines, adding to some of the significant fuel consumption savings on offer through the most advanced control of hydraulic flow and pressure seen on excavators to date.
Versatility is also central to the latest designs – excavators are expected to be reliable workhorses, built to be rugged and suitable for an ever-increasing range of applications.
And with sales of wheeled and crawler excavators in Western Europe forecast to rise 11% and 14% respectively between 2011 and 2015, now is the perfect time for manufacturers to broaden their market share and benefit from the upswing in demand.

Asian manufacturers
More and more Asian equipment manufacturers are pushing to establish themselves in Europe. South Korean company Doosan, for example, launched the first of a new generation of excavators this September – the 32 tonne DX300LC-3 crawler.
The new machine is powered by a 150kW Doosan and Isuzu Stage IIIB-compliant engine, which uses cooled exhaust gas recirculation (EGR) and a diesel particulate filter (DPF) to achieve emissions compliance.
The DX300LC-3 also features increased hydraulic pressure for improved lifting capabilities and breakout forces, and a floating boom system for reduced stress and vibration as well as improved control and operator comfort.
The excavator can carry buckets ranging from 0.8m3 to 1.75m3 and features new operating modes such as economic mode and power plus mode to improve efficiency and reduce fuel consumption. This machine will go into full production at the end of this year and introduction of the range – 15 models in total – will be spread over the next two years.
Chinese manufacturer Liugong also has plans to release the first two models in its E Series line of excavators, the 922E and 925E, in Europe during the first quarter of 2012.
The company has installed Cummins engines in the new excavators and claims the Stage IIIB power systems produce average fuel efficiency improvements of 5% compared with its D series predecessors.
The 22.4 tonne 922E can be fitted with a 127kW European Stage IIIB EGR/DPF engine and comes equipped with a standard 1m3 bucket, while the 25.6 tonne 925E has a 142kW Stage III compliant engine with a standard bucket size of 1.2m3.
Significantly, the 922E can also be configured with either Stage II or Stage IIIA engines – offering flexibility to contractors who may wish to use the machines outside the highly regulated European market, where the ultra-low sulphur fuel that many Stage IIIB EGR/DPF engines run on is not widely available.

European activity
There has also been a lot of activity from the European and North American excavator manufacturers.
Caterpillar, for instance, added to its new E series hydraulic crawler excavator line-up in September with the European launch of the 324E, 329E, 336E and 349E models.
The larger models, the 36 tonne 336E and 50 tonne class 349E were showcased at Conexpo, Las Vegas, US, last spring, while the new 24 tonne class 324E and 29 tonne class 329E machines were unveiled for the first time in September.
All the new excavators feature more efficient Stage IIIB/Interim Tier 4 engines that use EGR/DPF technology and have been combined with higher pressure hydraulics to increase both performance and fuel efficiency.
The 324E is powered by a 145kW engine which delivers 3% more power than its D series predecessor but consumes 5% less fuel. Hydraulic system refinements also give the machine up to 5% greater productivity.
The 329E features a 173kW engine and also boasts higher power and fuel efficiency than the model it replaces – improvements which Caterpillar says contribute to overall low operating costs.
Indeed, all the E series excavators feature a range of productivity-boosting technologies, including a new electric regeneration valve in the boom circuit and a hydraulic type valve in the digging-arm circuit to minimise hydraulic flow for further fuel savings.

High performance hydraulics
Volvo, too, has introduced high performance hydraulics to its first Stage IIIB excavators – the EC380D and EC480D, which between them cover the 38 to 50 tonne classes, while the smaller EC250D and EC300D models cover the 25 tonne and 33 tonne weight classes.
The new excavators feature a two-pump hydraulics system that combines the flow of both pumps for quick cycle times and greater productivity when only a single function is being used.
It can also prioritise flow according to the work being done – for example to the boom for faster raising when loading or in deep excavations, or alternatively to the arm during levelling or swinging during large slewing angles.
All four new models are powered by Stage IIIB-compliant Volvo engines, which use EGR technology to meet the European emissions requirements.
Said to offer fuel efficiency improvements over their predecessors of up to 13%, the EC380D and EC480D excavators are powered by 208kW and 245kW engines respectively, while the EC250D and EC300D models are powered by 151kW and 169kW engines.
Case Construction Equipment, meanwhile, has also focused on fuel efficiency in its new C series range of crawler excavators, the first four models of which were launched earlier this year.
Case said, “As rising fuel costs are now by far the biggest expense when running machines of this size, savings can be substantial, boosting the return on investment for end users.”
Powered by Stage IIIB compliant engines, the CX250C, CX300C, CX350C and CX370C models range from 132kW to 189kW and boast up to 5% faster cycle times and 10% fuel efficiency improvements, compared to their B Series predecessors.
The CX250C is a 25 tonne machine, the CX300C is 29 tonnes, and the two top machines are 35 tonnes and 37 tonnes respectively.
The Case Intelligent Hydraulic System is said also to have added to the fuel efficiency savings, and includes technology such as a boom energy save system, which lowers engine revs during boom operations, while the auto energy save system cuts engine revs when the joystick control levers are inactive.

New models
Case sister company New Holland has also unveiled the first two models of its new C Series range of crawler excavators. The 27 tonne E265C and the 31 tonne E305C also sport Stage IIIB engines and offer up to 10% fuel efficiency improvements.
However, while the Case excavators use EGR/DPF technology to meet the emissions requirements, New Holland’s new E265C and E305C machines use selective catalytic reduction (SCR) technology.
The main difference is that the SCR approach does not need a DPF, but instead uses a urea agent to lower emissions during combustion.
New Holland said the urea resin, which is called AdBlue in Europe, is readily available at all its dealerships. It said the average rate of consumption of AdBlue on the new excavator models is 5% of fuel, meaning that the urea tank would need to be refilled with every fourth or fifth fuel tank.
The company has integrated a level gauge on a new colour display inside the cab which gives an optical and acoustic warning when the AdBlue is running low.
Excavator operator Camillo di Giovanni, working for contractor SGI on a pipe laying project in Italy, praised the efficiency of the new E305C machine he used for the first time over the summer, and said there had been no problems with refilling the urea resin.
“We did not have any re-supply problems with AdBlue. The tank is topped up after four refills but I must admit that we have never reached the upper limit because we carried out the work in a methodical way,” Mr Giovanni said.

Wide range of tasks
From mass excavation and loading to trenching and construction, the new excavators being brought to the market must also have the versatility and ability to cope with a remarkably wide range of tasks.
A Hitachi ZX280LCN-3 helped boost productivity at a demolition site in Bytom-Bobrek, Poland, for instance. The 28 tonne machine dismantled a former ironworks, reclaimed the land and helped transform the area into a thick forest.
Hitachi’s Polish dealer, Tona, supplied coal handling company FHU MEDEX with the excavator for work on the project, which started in 2006 and is expected to last until 2013. It covers an area of 600,000m² and to date has produced around 200 tonnes of aggregates, which is then sold for use in road construction.
Tona managing director Piotr Zoszak said a ZX350LC-3 35 tonne machine was also used, chosen for its large loading capacity, efficiency and reliability. The machine impressed the contractor to the extent that it has purchased a new one to add to its fleet.
German contractor Jakob Bau was also looking for a rugged, flexible and reliable machine to add to its fleet. It selected a Wacker Neuson 14504 excavator – a 14 tonne machine that claims to be capable of performing a range of tasks beyond conventional excavation work.
With a compact frame measuring 2.8m high and 2.5m wide, the machine can fit into tight spaces. Berthold Jakob, owner of Jakob Bau, said the excavator was well-suited to the company’s current projects.
“One of our current development projects involves laying utility lines for a housing construction site in the Augsburg district of Pfersee. A lot of our work has to be done in confined spaces, which is where the 14504 really comes into its own, delivering enormous power and performance,” Mr Jakob said.
Contractors are looking for the most reliable and productive equipment when deciding which medium-sized excavator to purchase – they demand workhorse machines with large loading capacities and low down-time for operation on a wide variety of projects.
And while not all manufacturers are tackling Europe’s new emissions legislation using the same technology, the companies are having to meet the efficiency challenges posed by both regulators and contractors alike.

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