Operators Evaluate Doosan ADTs

Doosan introduced the DA45-5 articulated dump truck along with the smaller DA30-5 at Conexpo 2020, and since then, the company has invested in significant research and gathered input from customers to upgrade the models with additional features for increased productivity. But there aren’t too many additional features on the 45-ton DA45—at least not in the opinion of Andy Schaidle, operator/instructor for the International Union of Operating Engineers Local 649 in Bartonville, Illinois. “I'm really impressed with, as far as a new machine goes, the simplicity of it,” Schaidle says. “I really, truly am. It seems like with a lot of this newer equipment, they want to get too fancy with touchscreens and bells and whistles where you’ve got to watch YouTube videos to figure it out, or you’ve got to go and read the manual. This one is very simple, very basic. I think the layout is good.” Jay Patel, product specialist for Doosan who was on hand for the DA45 ADT Field Test, says the company’s approach to ease of operation was deliberate. “Our ADTs are very simple and easy to operate so you can get your novice operators up to speed fast, with 10 minutes of explanation, and then they’ll be ready to go on the job site.” Indeed, a look at the machine’s controls reveals little more than a simple steering wheel, a color monitor, and an easy-to-read set of buttons on the console for direct actions. “Basically, you put your foot on the brake, you put it in gear, you take off,” Schaidle says. “It's not alarms going off. If I want to change to the air conditioner, I turn it on. If I want to change the radio station, I can turn it off. I don't have to go through a monitor. It's not overcomplicated with a bunch of stuff that you don't need. “I could put somebody in it and I don’t have to teach him what all the buttons and screens and monitors mean, and all this extra stuff you’ve got to go through,” Schaidle says. “I feel like I could get a lot more people up to speed faster.” Doosan ADT cab features Doosan redesigned its ADT cab interior to provide better ergonomics and more operator comfort. There are more than a dozen new features inside, including a dashboard with a modified shape and a soft-touch automotive material—making it easier to clean—and a high-quality finish and appearance. Updates to the truck’s vehicle control unit include more robust hardware; a faster processor; more input channels for customized functions or further technology developments; and easy-to-connect, automotive-style connectors. The monitor has larger gauges for easier reading. User-friendly graphics and icons can be controlled by buttons on the display panel, and the panel has been improved with the capability to display multiple camera views for increased visibility around the ADT. Operators can toggle through the menu to access additional information such as machine status, service, and settings. The DA45 is powered by a Scania engine that achieves Tier 4-F with SCR and EGR, but without the need for a DPF. It has a ZF transmission and is a full-time six-wheel-drive unit with limited slip front and rear differentials. “This automatically engages whenever the machine detects any slippage,” Patel says. “It will distribute power evenly to any side that needs that extra torque. It also has inter-axle diff lock, which is a push button in the cab. This runs longitudinally from the front to the rear of machine, and with this, let’s say you’re in the sand or going uphill and you have some slippage, it will distribute one-third of power to the front, to the tractor unit, and two-thirds power to the rear, and that will also allow you to keep contact with the ground and equally distribute torque to where it’s needed the most.” Schaidle and fellow operator/instructor Todd Keeler had constructed ramps, moguls, and an angled haul road on which to test the machine. First, it was time to fill the bed with a load. The bright orange dump body made an impressive target for the excavator in the late summer sun. “The bed holds a lot more than I thought, it holds a lot more than it looks like it does,” Keeler says. “It was fairly easy to see, no higher than the excavator was sitting compared to the truck. A nice, wide bed, easy to target to hit.” Patel points out a prominent slope downward, toward the cab, at the beginning of the truck’s bed. “The sloping bed design allows us to trap the weight of the payload to the center of the machine,” he says, “for equal weight distribution to the front and the rear of the machine.” Distribution by design Weight distribution and stability were important in the ADT’s design, which was well thought-out from the cab through the turning ring to the bed and the rear axle. “The cab is a more compact design than you see with other solutions on the market, with a smaller snout; we’re able to achieve that based on how we mount our engine to the transmission and the rest of the driveline,” Patel says. “With this compact design, we’re able to make shorter turns. We have the shortest turning radius in the market, allowing us to produce shorter cycle times and increase productivity at the job site. “Let’s say you have a full payload, and you’re running full speed, and you need to make a tight turn,” Patel says. “Whenever you make a sharp left turn, all that weight will be distributed to the right side of the machine, and that will cause you to have some slippage.” Doosan has placed the turning ring in front of the articulation joint. “With our design, having the turning ring in front of the articulation joint, you’ll be able to keep all of the weight distributed equally on the left and right side of the machine, so you won’t have that kind of slippage,” Patel says. “That will give you a much safer machine, and even tire wear on all six tires.” Patel says some ADT manufacturers use two rear axles, while Doosan uses one axle with a tandem bogie design. “This allows us to have a greater range of motion and keep maximum ground contact with all six wheels on the ground. It’s safer going over uneven terrain; the wheels will operate independently.” Both operator/instructors noticed the action of the rear wheels as they hugged the ground while backing up slopes. “I was impressed with the walking tandems on the back, how it went over terrain and obstacles, and backing over the slope at a slight angle,” Schaidle says. “You could hardly tell you were going up,” Keeler adds. “It was nice and smooth, seemed like it had a lot of power backing up. And with all those wheels staying on the ground, it stands to reason. That’s a very good design.” Doosan says the front-mounted turning ring, the tandem bogie, and the truck’s sloping rear frame result in both rough and soft terrain capabilities and avoid the need for electronic aids such as traction control. Braking has also seen upgrades since the machine’s introduction. A new transmission retarder adjustment lever was added to the right-hand side in the cab below the truck’s steering wheel. Operators can choose from four levels of retarder force: 100 percent, 75 percent, 50 percent, and 25 percent. As an alternative, a keypad button is available and serves the same function as the lever. The truck’s accelerator pedal continues to allow for quick retarder power reduction with a slight press. "We have four types of braking systems," Patel says. "The engine and hydraulic retarder is automatically applied whenever you release the accelerator pedal. The service brake, you just use the foot pedal to apply that. We also have the parking brake, which will automatically activate when you turn the machine off, whether the switch is engaged or disengaged." The front suspension of the ADT has also been updated since its introduction. It has gone to a hydro-gas self-leveling system for greater shock absorption. Combined, these suspension system features are designed to allow for a better ride and operator comfort, especially when the truck is driven while empty. The truck’s hydro-gas cylinders connect to pressure accumulators. The accumulators and hydraulic system replace previous shock absorbers and a rubber spring. The updated suspension includes a self-leveling feature and the ability to change characteristics by adjusting the pressure. Also, the overall height of the front suspension can be changed by adjusting the suspension system pressure, which has also served to lower the transport height of the truck. The operator/instructors gave these "feel" features high marks. "The transmission shifted really smooth," Keeler says. "It seemed like it had a lot of power when it was loaded. I liked the articulation of the rear axle. It was pretty impressive to me when we backed up the slope. The hydraulics seemed good on it. The steering was nice and smooth. The bed went up fully loaded at an idle. I tried it just to see how much power it had. I was pretty impressed with the whole operation, really." Schaidle concurred. "I felt the ride over obstacles was pretty good," he says. "I was skeptical about being empty on the haul road compared to loaded and obviously it rode better loaded, but I was still impressed with it. It didn't jar around that much, and power-wise it seemed like it was on par with most of the ADTs I've run. All in all, I think it's a decent machine." Beyond the basics There are some features that do take the DA45 beyond the simple basics. A payload measuring system is standard. Operators can view each load’s weight on the LCD screen in the operator cab. An exterior traffic light-style indicator alerts excavator and wheel loader operators filling the ADT. They include three lights: red, yellow, and green. If the green light is illuminated, the truck is within the rate of payload. If the yellow light is illuminated, the operator is within 10 percent of the rated payload. If the red light is illuminated, the operator has overloaded the truck for the allowed payload. A rearview camera is also standard, as is an auto-lube system. Doosan says updates to the grease distribution system enhance the bearings' grease grooves to improve lubrication distribution and lower grease requirements by as much as 50 percent In addition, the DA45 tested at Local 649 had a prominent stainless-steel tube running from behind the cab into the dump body. “This is used for heating the bed of the machine,” Patel says. “It transfers heat from the engine exhaust to the piping in the body, allowing you to heat up the material if you’re in a colder climate, or, if you’re working with wet material, that will heat it up and allow it to slide out much easier.” Doosan ADTs are built at the company’s manufacturing facility near Elnesvågen, Norway, along the western coast of the country, approximately 235 miles from Oslo. This is a former Moxy plant that Doosan purchased in 2012. Schaidle and Peebles weren’t familiar with Moxy, but in comparison with other ADTs they’ve run, the DA45 stacks up well. “I’d say it’s very, very comparable to other ADTs I’ve run,” Keeler says. “In some respects, it’s a little better. I liked this cab better; I liked the simplicity of it. Pretty straightforward. Push a button, put it in drive, and you go. I like that I don’t have to guess what I need to do to operate it. I like that there’s no ‘What’s this button do, or what’s that button do?’ You know what it does.”