Many of the best construction sites for housing and industry in this country have been used up. More than ever, new construction is forced into sites with wet conditions and steeper grades. Those are the sites where excavators and articulated dump trucks shine. They are the best earthmoving tools for these difficult sites, as opposed to scrapers. An articulated truck is simply more productive at handling steeper grades and wet, mucky conditions.
As a result, there is no shortage of manufacturers that offer a range of alternatives in articulated dump trucks (ADTs). The list includes Caterpillar, John Deere Construction & Forestry, Case Construction, Doosan Infracore Construction Equipment America, Komatsu America, Terex, and Volvo Construction Equipment.
Take Doosan Infracore, for example. Last October the company launched the DA40 articulated dump truck, the first in a new family of such haulers. With a payload of well over 40 tons, this truck is powered by a six-cylinder Scania engine that is Interim Tier 4 compliant. The big 500-horse engine puts out 1,750 ft-lb of torque, a 22% increase over the previous model, the MT41.
Doosan says the DA40 burns 8% less fuel than its predecessor under standard working conditions. Helping to make that possible is a new transmission with eight forward and four reverse speeds.
To help meet Interim Tier 4 emission standards and save fuel at the same time, the Scania engine features high-pressure-unit fuel injectors. Fuel is injected into the cylinders at 25,000 to 30,000 psi, says Brian Bereika, ADT product specialist with Doosan Infracore. This high pressure creates a very fine mist of fuel that is injected-under electronic controls-at precisely the right instant.
Nitrous oxide emissions are controlled by Selective Catalytic Reduction (SCR), says Bereika. The SCR system injects a spray of urea-water mixture into the hot exhaust stream. The heat evaporates the water, and leaves ammonia, which reacts with the nitrous oxide to leave harmless nitrogen and water vapor.
“So as a result, we don’t have any particulate matter filters in the system because there is no exhaust gas recirculation,” says Bereika. “That means reduced maintenance for the end-user.”
Both the DA40 transmission and the one in the MT41 come from ZF (pronounced Zed-F, a German manufacturer). The former model had six speeds forward, but the DA40 has eight forward speeds in a fully automatic, power-shift transmission. “That way there are smaller gear steps and more of them, so it enables the transmission to find the proper gear while you’re operating the truck-rather than run the engine at high rpms at the extreme end of one gear,” says Bereika. “By operating in the right gear, the engine runs at lower rpms and that saves fuel.”
Let’s Go Mining
Volvo Construction Equipment makes one of the most popular articulated trucks out there. On Volvo artics, a unique A-frame suspension design on the front tractor eliminates dipping, a motion that causes the cab to thrust forward during full turns. The A-frame suspension ensures that the hauler stays on target after exiting a corner.
Volvo articulated trucks have full suspension, which the company says offers the best ride in the industry. Free-flowing hydraulic fluid is supplied to cylinders in the suspension system. The front suspension consists of two hydraulic cylinders and two accumulators. It works with the rear suspension, which consists of four hydraulic cylinders and two high-pressure accumulators for when the body is loaded, and two lower accumulators for when the body is empty.
Volvo says that full suspension makes the truck-operator combination more productive, and end users bear that out. I recently visited a coalmine site near Evansville, IN, where Volvo trucks were being used to haul coarse refuse, a waste product, away from the mine. The trucks hauled the refuse from a 300-ton elevated bin to build up an 8,000-foot-long dam that contains a slurry lake. This dam was huge; the lake covers 55 acres.
Four Volvo A40E FS articulated dump trucks haul the refuse to the dam. “These trucks run 24/5 and do about 45 miles per shift,” the project engineer said. “The plant puts out 570 tons per hour of refuse, so that means each truck hauls about 145 tons per hour.
“The trucks ride very smoothly,” the project engineer said. “Full suspension doesn’t necessarily affect fuel economy, but with full suspension an operator is going to move more material per gallon of fuel, because he can be more productive. I would estimate that full suspension gives us a gain of 10% to 15% in production versus trucks that don’t have that feature.”
Deere’s Biggest ADT
John Deere’s largest articulated truck, the 460E, is due for availability this summer. “We worked with customers to develop a truck that is purpose-built to reliably handle a 46-ton payload,” says Mark Oliver, ADT product marketing manager for John Deere Construction and Forestry. “This joint effort will help big earthmovers move more material faster and more efficiently.”
The Deere 460E features an on-board scale that reports payload weight in real time. When coupled with Deere’s JD Link, a telematics system, end users can monitor the amount of material moved each day and adjust haul road patterns, drivers and the like to maximize production. A 13.5-liter John Deere engine and Deere-made axles round out the package. The engine is compliant with Tier 4 Interim exhaust standards.
John Deere offers four other articulated trucks as follows: the 265-horsepower 250D Series II; the 285-horsepower 300D Series II; the 380-horsepower 350D Series II; and finally the 413-horsepower 400D Series II.
The Komatsu Option
At Conexpo last year, Komatsu America Corp. introduced the HM300-3 articulated truck. The HM300-3 is powered by a 325-horsepower Komatsu engine that is certified to meet Tier 4 Interim and Europe’s Stage IIIB emissions standard. The truck can haul a payload of 31 tons at a maximum ground speed of 36 mph.
The HM300-3 is equipped with a Komtrax system, which sends machine operating information to a secure website by using wireless technology. Data such as daily fuel consumption, machine utilization, operating hours, location, cautions and maintenance alerts are relayed to the web application for analysis. The Komtrax fleet monitoring system increases machine availability, reduces the risk of machine theft, allows for remote diagnosis by the distributor, and provides a wealth of other information to improve productivity, Komatsu says.
The HM300-3 also features the new Komatsu Traction Control System (K-TCS). That system automatically provides optimum traction control when operating in soft ground conditions. As ground conditions worsen and tire slippage is detected by speed sensors located four wheels, the inter-axle differential lock is automatically applied. If tire slippage continues, then four independent brakes can be applied to slipping wheels to regain traction.
In December last year, Komatsu introduced the HM400-3 articulated truck. It is powered by a 469-horsepower Komatsu engine that is certified to meet Tier 4 Interim and Europe’s Stage IIIB emissions standards. The truck can haul up to 44 tons of material at its maximum ground speed of 34.7 mph. Like Komatsu’s 30-ton truck, the HM400-3 is equipped with Komtrax and the special traction control system.
Through body design optimization, the HM400-3 features increased body capacity and payload. The low loading height of 10-feet, 5-inches easily matches with 40-ton to 60-ton excavators or 5.5-yard to 7.5-yard wheel loaders. In addition, the two single-staged body lift cylinders provide a 70-degree dump angle.
New From Caterpillar
Last year Caterpillar introduced its next generation of articulated trucks, the new B Series models. The lineup now includes the 735B with a 36-ton payload; the 740B with a 43.5-ton payload; and the 740B EJ with an ejector body that carries 42 tons. All three trucks are available with either Tier 2/Stage II equivalent or Tier 4 Interim/Stage IIIB engines to meet the demands of customers around the world. Both configurations feature revised transmission and traction control systems for improved productivity.
Caterpillar has further improved its six-wheel drive system. A new, fully proportional automatic traction control (ATC) system eliminates the need for any driver intervention to maintain maximum traction in difficult operating conditions. In Caterpillar’s previous generation of ADTs, the operator had to manually engage floor- and dash-mounted switches to bring cross- and inter-axle differential locks into play. But with the new proportional ATC system, the truck automatically and constantly varies the required proportion of lock-up on both cross-axle and inter-axle diff locks as underfoot conditions change. That way the operator can concentrate on driving the truck without having to think about traction control.
Caterpillar has also improved the automatic transmission in its articulated trucks. Gear changes are much smoother, as torque is maintained through each gear change, which results in improved acceleration, especially on grades. Part Throttle Shifting at lower speeds results in improved fuel efficiency and easier machine operation.
If you want a larger rigid-frame truck, you should try out the new Cat 775G Off-Highway truck. A combination of new drive train strategies and a 5% power increase over the previous model enable this 70-ton truck to hold a higher gear when climbing 10% grades in most applications.
A number of new components and control changes boost efficiency on the Cat 775G. A key is Caterpillar’s new generation of transmission controls, named Advanced Productivity Electronic Control Strategy. According to the manufacturer, the system enhances production, fuel efficiency and drive train durability. For example, to balance fuel savings and production, two different economy shift mode selections enable the operator to tailor performance to the needs of the business.
If you want an on-highway truck, you won’t want to miss the Cat CT660, the first model in a full line of Class 8 vocational trucks designed to work as dump trucks, transit mixers, and refuse haulers. Caterpillar’s Steve Gosselin, a vice president in the company, calls the introduction “an exciting historic milestone for Caterpillar.”
Engine options on the CT660 include the Cat CT11, CT13, and CT15, which provide horsepower ratings ranging from 330 to 550 and peak torque ratings from 1,450 to 1,850 lb-ft. The engines combine an advanced exhaust-gas-recirculation system with a high-pressure common rail fuel system, precision intake-air management system and electronic controls to optimize performance, low emissions and fuel economy.
The Compact Graphite engine block reduces weight by as much as 500 pounds compared with conventional all-iron designs. Reduced engine weight enables you to increase payload.
A notable transmission option for the CT660 is the Cat CX31 automatic, a proven performer since 2004 in global vocational applications. The transmission has six forward speeds and one reverse, and is built to complement the torque output of Cat CT Series engines. The transmission features heavy-duty clutches and gear sets that allow full-power shifts, which increase efficiency.
The Terex-Scania Solution
Terex marks an entry in the articulated truck business with a TA300 Generation 9 model, which is powered by a Tier 4 interim compliant Scania DC9 engine that pumps out 370 horses. Terex says the TA300 boasts a 12% reduction in fuel consumption, a two percent boost in power and a 6% increase in peak torque, compared to the previous model.
“With a maximum payload of 30 tons, a body dump cycle time of 20 seconds and a 23-yard heaped capacity, customers will benefit from this truck’s low cost-per-ton per hour,” says Ken Emmett, product manager, Terex Construction.
The TA300 is equipped with a ZF fully automatic transmission with manual override and retarder, six forward gears and three reverse gears. Terex says the truck is well suited for construction, mining, quarrying and road maintenance.
Terex says the standard Independent Front Suspension (IFS) system on the TA300 provides a smooth ride over rough terrain, which improves operator productivity. Shock loads and vibrations are reduced, which increases component life and improves operator comfort.
Another important feature of the Gen 9 TA300, and all Terex articulated haulers, is the oil-cooled multiple disk brakes on each axle. The results are extended brake life, reduced service intervals, lower operating costs, and better overall braking performance in comparison to dry-disc brake systems used by other manufacturers.
Terex also offers a TA400, an articulated truck with a payload capacity of 40 tons and a heaped volume capacity of 22.9 cubic yards. The truck has a gross horsepower rated at 444, with six forward gears and one reverse in addition to a two-speed drop box. The TA400 can travel up to 37.3 mph.
New From International Trucks
At last year’s Conexpo, Navistar unveiled its International PayStar severe service truck powered by the all-new MaxxForce 15 big-bore diesel engine. Depending on customer need, the entire lineup of MaxxForce big bore engines, the MaxxForce 11, the MaxxForce 13 and the MaxxForce 15, all available for ordering with the PayStar truck.
The MaxxForce 15 is available with up to 550 horses and 1,850 lb-ft of torque and is the most powerful engine that Navistar builds. The engine is built on a proven block and crankshaft. The engine uses Navistar fuel systems, air management and electronic controls with an Advanced EGR system for meeting air quality standards.
The MaxxForce 15 uses a high-pressure common-rail fuel system, dual sequential turbochargers, an effective heat management system and low-friction design to deliver more torque and responsiveness at low engine speeds. The result is improved fuel efficiency. Peak torque is achieved at 1,000 rpm and holds steady to 1,200 rpm, a much lower speed than other big bore engines.
Make It a Volvo
Volvo’s VHD vocational truck is designed for construction applications and can be spec’d with either a Volvo D11 engine with 325-405 horsepower or a Volvo D13 engine that puts out 375-500 horsepower, depending on how the engine is configured. Available transmissions include the Volvo 12 speed or a range of Eaton Fuller transmissions or Allison 4000 and 4500 Generation 5 gearboxes.
Volvo says the VHD gives you a panoramic, one-piece windshield and sloped side windows. A wheel cut of up to 50 degrees helps deliver one of the tightest turning radiuses in the industry. The standard Volvo T-ride suspension features trunnion-mounted springs and rubber towers for excellent traction and articulation in off-road situations.
