T4-I, Hydraulics, Controls Boost Excavator Productivity

Feb. 27, 2013

Manufacturers in the 60,000- to 80,000-pound hydraulic excavator class have been busy adding Tier 4-Interim engines but also refining controls and the way engine and hydraulic power can be used, leading to productivity gains in this stalwart category seen in road building, general excavation and site preparation, and smaller stone or quarry operations.

Questions Before Buying

Sizing the excavator for the job is a critical factor when purchasing the unit.

Manufacturers in the 60,000- to 80,000-pound hydraulic excavator class have been busy adding Tier 4-Interim engines but also refining controls and the way engine and hydraulic power can be used, leading to productivity gains in this stalwart category seen in road building, general excavation and site preparation, and smaller stone or quarry operations.

Questions Before Buying

Sizing the excavator for the job is a critical factor when purchasing the unit.

To do it right, Doosan’s Mike Stark recommends answering a deliberate set of questions tied to attachments and applications. First, consider what attachment is going on the excavator and ask the following questions:

Does the excavator have enough hydraulic pressure and flow to operate the attachment? Does the excavator need one-way or two-way hydraulic flow for the attachment?

Also, there’s the need to match the excavator and bucket size to the job site and materials. How heavy is the material to be lifted, and then how large of a bucket is needed to be most productive? This will help determine the size of excavator needed.

What is the primary application involved? If it’s loading a truck, what is the dump height needed on the excavator? How large is the truck? Remember to optimize the size of the truck with the excavator and bucket size. If trenching is in order, how deep and wide will the trench be?

“Excavators are very versatile machines, generally contain multiple configurations, have many attachment options, and are capable of a wide range of different activities,” adds Brian Yureskes, Komatsu’s product marketing manager-excavators. “The better an equipment manager understands the application, the process of selecting the correct excavator becomes much more efficient and will help ensure maximum machine peformance and productivity.”

While many of the upgrades have been done in conjunction with adding the T4-Interim engines, others have been due to customer demand in the marketplace, such as for better attachment capabilities.

The excavator market, though faring better recently, is still somewhat of a mixed bag.

“From our view, certainly since 2007 and 2008, the market hasn’t been great,” says Chris Giorgianni, VP of product for JCB. “But we’re seeing recovery across the board. We’ve had success in excavators, more in the 14- to 22-ton sector than this one, but in the last 12 to 18 months, we’re on what we feel to be an upswing. I don’t think any of us see ourselves out of the proverbial woods yet.”

Excavator Owning Costs

Size class (metric tons)Average priceHourly rate*
24.1 - 28$236,315$102.13
28.1 - 33$268,407$113.65
33.1 - 40$325,603$137.78

*Hourly rate represents the monthly ownership costs divided by 176, plus operating cost. Unit prices used in this calculation: diesel fuel, $4.13 per gallon; mechanic’s wage at $50.76 per hour; and money costs at 2.0 percent.
Source: EquipmentWatch.com

Mike Stark, excavator product specialist for Doosan, also notes a relatively recent change.

“Last year we finally saw people starting to change out their fleets,” Stark says. “At the same time, we’re still seeing a lot of equipment going into rental; people are still cautious. They’d rather rent versus buy. This year, I am hearing it will be a flat year.”

However, Stark says the 60,000- to 80,000-pound category is a sweet spot of demand. “This 33- to 40-ton range, where our DX300 and DX350 models are, especially the DX350, is our highest market right now,” he says. “Most of our latest improvements have been on the 350, particularly big changes in hydraulics.”

Hydraulic and control changes

Doosan’s 281-horsepower DX350LC-3 is a typical example of how manufacturers are changing the way power can be used. The DX350 now has four power modes (Power+, Power, Standard, Economy) and four work modes (Digging, Lifting, Breaker, Shear), part of a trend of giving operators many choices for power and control.

“One of the new features is the Power Plus, where we boost hydraulic pressure to give a little more power to get through a tough application,” Stark says.

The unit also has additional horsepower in its Tier 4-Interim engine, along with more torque, and a 6 percent increase in maximum pressure from the main control valve. Swing torque is increased by approximately 8 to 11 percent, Doosan says, with digging force seeing a 5 percent increase. Lift capacity has a 2 percent improvement, with boom-up speed improving by 6 percent.

“With the hydraulics, customers really notice a difference in the control of the machine,” Stark says. “They feel a sense of power. That has to do with the electronically controlled hydraulic pump. With the ‘old method,’ you’d run the hydraulics full on. Now, at the highest power, more oil is pumped as it’s needed, at the hydraulic pressure needed. When you operate the joystick under load, the machine senses what you need for pressure and flow, and you get the best utilization of power—it adjusts pressure and volume automatically.”

Additionally, the new Intelligent Floating Boom option allows the boom of the excavator to “float” up or down, allowing the operator to focus more on the task while decreasing the machine workload. The float mode allows the boom to move freely up and down without utilizing hydraulic flow. The breaker mode allows the boom to freely move down, only without utilizing hydraulic flow. The operator has the ability to momentarily disengage the float, allowing hydraulic flow to activate the boom.

More attachment use

“More customers are increasing machine versatility through the use hydraulically driven attachments,” JCB’s Giorgianni says. “In the past, this size class was primarily an excavating machine, but now people are expanding operations and increasing utilization because there are not as many jobs out there. We’re seeing a lot more hydraulically driven attachment use.”

Manufacturers have responded with more couplers, and attachment-friendly work modes and hydraulic settings.

“In terms of attachments, the monitors themselves have improved,” Stark says. “Before, you could set up attachments but you couldn’t necessarily control the hydraulic pressure and flow. Now, we have five pre-sets for one-way spool, and five for two-way flow. If you have an operation where you change attachments quite often, that’s very handy.”

Volvo’s EC250D and EC300D feature an attachment management system, which stores up to 18 different attachment presets. This allows hydraulic flow and pressure adjustments to be set according to the needs of the tool being used, at the touch of a button.

The industry has also seen more manufacturers install quick couplers for excavators, allowing users to switch out attachments in minutes, rather than taking the time to pull pins. Excavator makers are also working in tandem with their dealers to satisfy special requests.

“Breakers are another popular attachment on these machines, but we’re seeing more special applications as well,” Stark says. “We’re willing to work with customers. We see it a lot with shears for demolition, where they want to take the boom off. You can just replace the bucket with a shear if you want, but in many cases they’re taking the entire arm off and replacing it with a huge shear. I’ve seen them used in demolition or scrap yards where they bring engines in and the shear breaks them apart, and separates the aluminum, steel and cast iron.”

Stark says that equipment managers have to choose two-way hydraulics for shear work, to accommodate the open-and-close action. “Also make sure you size the machine right, and size the attachments to the machine, so you have enough flow and hydraulic pressure to operate the shear to its full capacity,” he says.

In another trend, users are keeping excavators longer, post-recession. OEMs have noticed and adjusted their offerings accordingly.

“From a 20,000-foot level, asset-wise—not just excavators—managers are keeping machines longer,” says Giorgianni. “It’s definitely been extended. They look at the versatility they can achieve with attachments over a three-, four-, or five-year life. Maybe they don’t want to burden themselves with a new payment, so there’s an extension of the ‘first use life.’”

Giorgianni also says he’s seeing an increase in maintenance plan purchases as Tier 4 rolls on. Customers are less knowledgeable about the technology, and dealers have more expertise at the moment. In addition to offering more maintenance plans, manufacturers are increasing serviceability, seemingly with every update.

“The demands vary depending on the size and needs of the fleet, but the common thread is the need for uptime based on serviceability,” says Rob Marringa, manager, brand marketing, Heavy Product Offering, for Case Construction Equipment.

“Profitability for equipment owners is directly related to the machine’s hours on the job—without breakdown,” he says. “Daily maintenance is the single best preventive step a manager can employ. Our new C-class excavators ensure that key maintenance points have easy access, ground line access to cab, fuel, and hydraulic filters, and longer service intervals to keep the operator in the driver’s seat. Features such as EMS bushings help to stretch service intervals, reducing downtime, so profitability grows.”

With Tier 4-Final changes looming on the horizon, expect companies to include another round of efficiencies in tandem with new engines.

“With Tier 4-Final, we’re focusing on further enhancements to make the machines easier to operate,” Giorgianni says. “We have some things in the works as far as increasing the ease of use, therefore making the operator more productive. In the end, it’s all about production.”