Haulers: Meeting global demand

Global demand for haulers and scrapers is forecast to increase this year in both developed and developing markets.

One driver is the rise in heavy construction such as road building, particularly in high-growth economies such as India. Another factor is the general growth in construction activity around the world, which drives demand for cement and aggregates, and therefore the need for haulers in quarries.

According to Off-Highway research, sales of rigid haulers are expected to increase +14% year-on-year by the end of 2011 to more than 2000 units, while +9% more articulated dump trucks (ADTs) are expected to be sold around the world, for a total of over 2500 units.

Tentative signs of a market uptick are also present in the smaller scraper market, where +12% more machines are predicted to sell in 2011, totalling around 240 units by the end of the year.

But despite the worldwide demand, the focus of new machine launches has been skewed towards the North American and European markets, which saw the introduction of new Interim Tier IV in the former, and Stage IIIB emissions legislation in the latter at the start of the year.

The key change from the previous laws (US Tier 3/EU Stage IIIA) is that manufacturers have had to make a large cut in emissions of harmful nitrogen oxides (NOx) and particulate matter (the visible black soot that comes out of a machine's exhaust pipe).
To comply, the major manufacturers have stuck to two main approaches - selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) with a diesel particulate filter (DPF).

SCR involves treating exhaust gases with a urea resin to convert harmful NOx into inert nitrogen and water. This requires an on-board urea tank to be accommodated in the machine, and also relies on the availability of the urea agent in the country that the machine is being operated.

EGR reduces emissions by cooling and pumping a proportion of the exhaust gas back into the engine's cylinders to reduce combustion temperatures. This cuts NOx but leads to more particulates which are removed from the exhaust stream by the DPF. Again, this adds bulk to the engine system.

Both methods rely on ultra low sulphur diesel, which is hard to get outside of Europe and the US. Using high sulphur diesel with either system would lead to the aftertreatment module becoming blocked with soot, causing a damaging and expensive engine breakdown.
This year's new emissions laws have affected all types of off-road hauler up to about 100 tonnes capacity. Larger engines than 560 kW are exempt from the regulations, and this mainly applies to mining class trucks. As far as haulers for the construction industry are concerned, all models are affected.

As a result a flurry of new ADTs have been launched this year aimed at the North American and European markets in which they are traditionally popular, and the majority of manufacturers - including Komatsu, Caterpillar, Volvo, and John Deere - opted to reduce emissions using engines with EGR technology and DPF systems.

Doosan and Terex, however, stand out in their selection of Scania engines with SCR technology. In September, Doosan launched the first two articulated dump trucks (ADTs) in its new DA range - the 276 kW DA30, which has an unladen weight of 22.4 tonnes and can carry a payload of 28 tonnes (with tailgate), and the larger DA40 is powered by a 368 kW engine and has an unladen weight of 30 tonnes and can carry a 40 tonne payload.

Two-tier manufacturing

Both new models include Stage IIIB/Interim Tier 4 Scania engines - a feature which Doosan said was significant because Scania manufactures both Stage II and Stage IIIB engines from the same block, removing the need for two-tier manufacturing when producing machines for different markets.

Doosan acquired the ADT range when it bought specialist manufacturer Moxy in 2008, however it is marketing its latest trucks under just the Doosan brand, rather than the previous Doosan-Moxy marque. See equipment page 47 for more information on Doosan's latest equipment launches, including its plans for a 50 tonne ADT and market commentary from Doosan Infracore Construction Equipment CEO Tony Helsham.

Terex has also unveiled a new ADT range - Generation 9 - that is powered by Scania's SCR technology Interim Tier IV/Stage IIIB-compliant engines. There are three new haulers - the 25-tonne class TA250, the 30-tonne class TA300 and the 40-tonne class TA400 - and these machines are said to over a -12% reduction in fuel consumption.

Scania claims that because the conversion to SCR does not require a particulate filter, it involves only minor changes to the installation, unlike the EGR/DPF approach.

In addition, Scania has highlighted the fact that using SCR at the Interim Tier 4 stage will likely stand OEMs in good stead for when the Tier 4 Final emissions regulations kick in from 2014 - laws that demand a further reduction in pollution that many engine manufacturers have acknowledged can only be achieved with a combination of technologies.

Nevertheless, the most popular choice among ADT manufacturers for meeting the emissions challenges has been EGR and DPFs. Volvo, for example, unveiled its new F-Series range of ADTs which feature low emission Interim Tier 4 /Stage IIIB engines and are said to be up to +4% more efficient than their E-series predecessors using the EGR/DPF combination.

As well as the new engines, automatic traction control (ATC) systems are now being included as standard on many of the latest launches, while manufacturers have also focussed on developing new safety controls.

Traction control

Volvo's six-machine series ranges from the 24 tonne A25F up to the 39 tonne A40F, and all the new models feature ATC as standard - a system which automatically disengages the rear axle when not needed, eliminating tire skid when cornering and reducing tire wear, but kicks in again when it senses slippage.

John Deere, which owns a stake in South African ADT specialist Bell, has also broken the mould with the launch of its largest ever ADT, the 46 tonne 460E. The first of Deere's new E-Series ADTs, due in 2012, this monster hauler is powered by an US/EU emissions-compliant 13.5 l John Deere EGR engine, and traction controls have also been automated to take the guesswork out of when to use the differential locks for inexperienced operators.

Mark Oliver, ADT product marketing manager for John Deere, said the company had responded to customer demand for an ADT with a larger capacity for big hauling jobs. An on-board weighing scale is also included as standard, letting operators know when the dump body is loaded to capacity.

By entering the 50 tonne weight range, John Deere's 460E is competing with the lower end of the rigid hauler market, but its additional floatation, six-wheel drive and independent rear axles give the ADT a distinct off-road advantage over its rigid counter-parts.

While both rigid and articulated trucks perform well in dry conditions on well-maintained roads, rigid trucks do not, generally speaking, perform well in grades above 10%, while ADTs are often capable of managing grades of 20% or more, even in muddy or rough conditions.

John Deere's 460E features a newly designed oscillation joint, high-suspension travel on all axles, and balanced weight distribution to provide the agility to navigate such hostile terrain.

Komatsu's new emissions-compliant HM300-3 ADT has also been designed with increased automation, security and fuel efficiency in mind. Launched in Europe this summer after being unveiled it in North America at ConExpo in March, the 25 tonne machine is capable of hauling up to a 28 tonne payload.

Power comes from a 325 hp (242 kW) Komatsu SAA6D125E-6 Tier 4 Interim and Stage IIIB engine, and the HM300-3 features manufacturer's Komtrax fleet monitoring technology as standard. This is a wireless system which sends machine operating information such as daily fuel consumption, location and operation hours to a secure website.

And the SAA6D125E-6 features Komatsu's traction control system (K-TCS), which automatically provides optimum traction for different ground conditions.

Caterpillar's new generation of ADTs, meanwhile, features an automatic proportional differential locking as standard - a system which adjusts itself to different transmission loads and works in harmony with the hydraulic steering system.

The company launched three ADT models in March for the European and US markets - the 735B, offering a 32.7 tonne payload, the 740B with its 39.5 tonne payload, and the 740B EJ with an ejector body, carrying a 38 tonne payload.

The three B Series trucks feature Caterpillar's Interim Tier 4/Stage IIIB EGR engines, and, significantly, the manufacturer said all of its new engines would be installed "for those countries that require them."

Divided market

And the company has touched on a key issue here - one of the effects of the new emissions laws in the US and Europe is that they have divided the global hauler market into regions that require expensive low-emission engines, and regions that require less complex technology or have no regulation at all.

The cost of the new, emissions-compliant machines is just one part of the issue - it would be a costly mistake indeed to use the wrong fuel on an Interim Tier 4/Stage IIIB EGR engine, making these machines practically unusable in places where ultra low sulphur diesel is not widely available.

This is not a huge problem for the primary sale of the latest ADTs, but it may be a something of a time bomb for the international used equipment market, which could see machines re-sold to contractors outside the traditional ADT markets of Europe and North America.

While it may well take some time for the rest of the world to impose the same emissions limits that apply in the US and Europe, hauler manufacturers can still be relied upon to push for efficiency savings and increased productivity regardless of the power system in place in order to expand their international market share.