ADT/RDT haul truck development sees lot of activity
First publishedin Aggregates Business Europe & International
Caterpillar has been working on its ADTs as well as its rigid quarry trucks. The 725C is one of the latest models to be upgraded
Changes in the hauling market don’t move with quite the same speed and regularity as the excavating and loading sectors, writes Dan Gilkes.
For one thing there are fewer players in the truck market and, in the Case of larger rigid trucks at least, there is not as much regulation in terms of engine emissions driving the constant upgrades that we see in smaller equipment.
What’s more, many of the larger RDTs are working in territories that do not have as tough emissions standards to comply with as European and North American customers.
That’s not to say that truck development stands still however: far from it. The articulated dump truck (ADT) sector in particular has seen a lot of activity in the past year and there will be a number of additional developments during 2014.
The biggest news in the dump truck market though doesn’t involve engine technology or individual machine specification. It is more the fact that Volvo is once again heading back to the rigid dump truck market, having agreed the purchase of the Terex truck business. It’s been some years since Volvo was tied up with Euclid, though the company has continued to build larger digging and loading equipment.
We have yet to see how the acquisition of Terex trucks will play out, particularly with both companies building competing ADTs, but for Volvo having a full truck range to work with its larger wheeled loaders and tracked excavators is definitely a major positive move.
Terex had most recently been working on updates to its rigid truck line, with the TR60 in particular undergoing a major overhaul last year. The 55tonne capacity truck now benefits from dual retardation systems for maximum safety and control on descending haul roads. Improvements to onboard diagnostics and centralised hydraulic test points have also increased serviceability on site, reducing downtime for quarry operators.
Volvo has shown the first of its G Series ADT range
Caterpillar remains a dominant force in off-highway quarry rigids and the company has recently updated both its 770G and 772G models. The 36 and 47 tonne capacity RDTs are available with a choice of Tier 2, Tier 3 and Tier 4 Final engines, to suit various territories and emission levels around the world.
Whichever emission level you choose, the C15 and C18 Cat engines can both be programmed to meet specific customer efficiency goals. There are two modes available, Economy and Adaptive Economy. Economy mode lets the customer de-rate the engine output by between 0.5-15% across all sections of the haul cycle.
With Adaptive Economy mode the truck monitors demand and delivers fuel savings when possible, for instance when running unladen or downhill. However it maintains power delivery as required for laden and uphill hauling. The trucks also feature a new Auto Neutral Idle system that automatically puts the transmission into Neutral after the brake has been applied for more than 15 seconds. This AIMS to reduce parasitic driveline losses and further boost fuel economy if the driver is sitting with the truck in gear for any length of time.
Hitachi has updated its RDT line with the introduction recently of the EH1100-5. With a nominal payload of 63.5tonnes, the EH1100-5 is powered by a 567kW Cummins QSK23 engine, driving through an Allison auto transmission. Outside North America customers can also choose a similarly powered MTU engine if preferred, while both diesel units are set to meet Tier 2 emissions regulations, due to their high power output.
The truck’s upgraded cab features a 10.1” LCD screen that doubles as both an instrument panel and a monitor for a reversing camera. Rear axle wet disc brake assemblies, which feature additional brake area for increased retardation, now incorporate an integral parking brake as well.
Hitachi can also set the EH1100-5 with a speed limiter, automatically restricting top speed on site if required by the customer.
As mentioned, there has been a lot more happening in the ADT market than with rigid truck design. While buying up the competition, Volvo has also been concentrating on its own range of articulated trucks, showing the first of the G Series range at the recent Conexpo-Con/Agg show in the US.
Hitachi's EH1100-5 is introduced to the company's RDT line
Powered by Tier 4 Final engines, the G Series trucks have an automatic traction control system that switches from 6x4 to 6x6 drive automatically as required. All differentials can be 100% locked and Volvo’s Full Suspension system is available as an option on both the A35G FS and the A40G FS.
Caterpillar has been working on its ADTs as well as its rigid quarry trucks. The 725C and 730C are the latest models to be upgraded, gaining Tier 4 Final engines, a new six-speed powershift transmission and a new automatic traction control system.
Unlike previous models, that had a pedal on the floor of the cab to activate the differential locks, the system works completely automatically on the C Series machines, without any input from the driver.
Braking power has been greatly improved too, thanks to the adoption of an engine brake on the 730C. This brake system is said to offer up to 60% more retardation than on older models, and is capable of almost bringing the laden truck to a standstill without the operator having to use the service brakes.
The 730C can be ordered with an ejector body if preferred and both trucks can be supplied as bare chassis cabs, for use as service trucks, water spray vehicles and for waste handling and hook-lift applications.
Komatsu has moved to Tier 4 Final this year with its HM300 articulated hauler
Doosan is another manufacturer that has installed Tier 4 Final engines in its ADT offering. The latest DA40 uses a Scania engine with selective catalytic reduction to meet the emissions standard. Doosan claims a best in class fuel consumption figure, despite a 15% rise in payload capability, compared to the firm’s previous MT41 trucks.
Bell Equipment has now introduced the first two models in its E Series range of trucks. The B25E and the B30E offer payloads of 24tonnes and 28tonnes respectively and are said to deliver the best payload to weight ratio in their class.
One of the big changes for the E Series is the new cab environment, with its 10” full colour screen and automotive-style mouse interface to control the many functions of the monitor. An air-suspended seat, fully adjustable steering column and high output audio system complete the upgraded interior.
Not to be left out, Komatsu has moved to Tier 4 Final this year with its HM300 articulated hauler. The truck uses Komatsu’s own SAA6D125E-7 engine, rated at 242kW and, once again, the company is claiming fuel savings over the older model.
The latest Doosan DA40 is fitted with Tier 4 Final
The HM300 comes with Komatsu’s Traction Control System (K-TCS) that automatically applies the inter-axle differential locks in the event of tyre slip. K-TCS can also apply the brakes briefly if required to regain traction for a spinning wheel. The truck also gets an automatic retarder that permits the operator to choose a maximum downhill speed to suit the grade and the load.
Though perhaps not a big player in the quarry market, some smaller sites with poor ground conditions could find a use for the Hydrema 12tonne payload 912 dump truck.
This compact machine has recently had an engine change, from Perkins to a Cummins Tier 4 Interim QSB4.5L engine. Though delivering up to 8% more power than the previous powerplant and 20% more torque, the Cummins engine boasts the same fuel consumption as the previous engine as it is not working as hard.
The Hydrema has an improved engine cover that now lifts clear of the chassis for easier access to the engine and transmission. The air conditioning unit has also been moved to provide improved serviceability.
Whatever your manufacturer of choice, the seemingly unrelenting march of progress continues, resulting in improved productivity from increasingly powerful drivelines. Yet despite this boost in output, somehow manufacturers seem to be finding fuel savings and other efficiency gains that go some way to offset the premium purchase price that emissions regulation requires.
There also seems to be far greater focus on operator comfort and assistance, with continued adoption of automated control systems such as traction control and differential locks. This can only be a good thing, driving improved safety on site, reducing damage to and abuse of components, plus lowering operating costs..