New Excavator Technology Allows for Smarter Construction

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Computers installed in today's 30- to 40-ton hydraulic excavators amplify the many aspects of operation by actually making production decisions. Equipment manufacturers have effectively leveraged the cost-effective capabilities of technology to produce excavators that feature:

Excavator Digging

Multiple work modes

The Environmental Protection Agency's 2003 Tier-II emissions deadline brought engine updates across the 30- to 40-ton excavator class. With their electronic fuel-injection controls, virtually all of the engines are more powerful than engines used in preceding models (up to 19 percent more horsepower). And with the ability to fine-tune fuel injection as the work changes, most of the new engines use in the neighborhood of 10 percent less fuel.

Average Excavator Costs

Size range List price Hourly cost*
61,800 to 72,600 lbs. $256,831 $78
72,601 to 88,000 lbs. $303,011 $90

* Monthly ownership cost (based on list price) plus operating expenses, divided by 176 hours

Machine controllers now offer operators the choice of multiple work modes, each designed to assign hydraulic priority to the circuits most critical to production in common excavator jobs. For example, stick and boom get flow priority in the digging mode while the attachment circuit gets priority in attachment mode. The problem with previous generations of excavators is that operators had to be trained to use the right mode at the right time. That seldom happened, and productivity and efficiency suffered when work was done in the wrong modes.

To simplify the choices, many of today's machines offer an Automatic mode. The machine's computer senses system pressure and the operator's lever inputs then adjusts hydraulic priorities automatically to accomplish more efficiently what the operator wants to do.

Sensors in the hydraulic systems integrated with controllers on both the hydraulic pumps and engines have made the power-boost feature common. If the machine's working circuits reach standard relief pressure for more than a second or two in tough digging, the systems automatically boost main pressure about 10 percent for a short period (usually around 10 seconds). Machines can handle the heavier load for short spurts, and the extra power can help push through a tough job. Several manufacturers put a button on the joystick that operators can push to boost power on demand.

The availability of work modes varies by manufacturer:

Electronic controls

When you ask manufacturers' excavator product managers which single technology had the greatest impact on their product category over the past 24 months, virtually all of them talk about electronic controls that now do more than just sense conditions. They provide feedback - either at the monitor or in the form of adjustments to hydraulic and engine performance.

It's a sophistication bordering on artificial intelligence that makes the machines more effective and efficient. Electronic systems provide information that improves diagnostic ability and helps owners make the best choices about how to use the machine effectively.

Tracking performance data

Along with the other electronic improvements, many excavators now include built-in data tracking that records all operating parameters, including:

To simplify management, data can be downloaded easily with a hand-held computer. Once it's uploaded to a personal computer, it can be graphed for easy analysis and used to fine-tune both the machine and the operator as well.

Simplifying maintenance and extending service intervals

In addition to on-the-job performance, technology is improving durability and ease of service too. For example, today's engines in the 30- to 40-ton excavator class have more heat to dissipate because of intercoolers between turbocharger and cylinder head, so many machines are now cooled by a fan with hydrostatic drive. Responding to information from a thermostat, the engine controller tells the hydrostatic fan drive when to come on and how fast to run. The fan uses only enough power to hold the engine in a safe operating-temperature range. Deere and some others have added an airfoil fan to variable fan drive to save significant horsepower.

It's not a coincidence that there's a service-interval race going on in hydraulic excavators at the same time so much electronic technology is being applied to the machines. Most of the diesel engines in today's excavators are designed for 500-hour oil-change intervals. The engines are working harder than ever. But computer controls have softened the sharp peaks in horsepower demand and they monitor and respond to coolant and oil temperatures and pressures better. New filter technologies are buying time for oil, too.

In the interest of aligning basic service at the same interval as the engine-oil change, manufacturers are applying special metallurgy and seals to bushings and pins in boom, stick and bucket joints to stretch greasing intervals. John Deere and Komatsu excavators are at 500 hours, and all the front-linkage pins except for the bucket joints on Cat and Case machines now require grease only at 1,000-hour intervals.

High-end hydraulic filtration and more-effective cooling have extended hydraulic-oil service intervals as long as 4,000 hours. For example, Link-Belt's LX Series machines come standard with a factory-installed bypass filtration system called Nephron.

Excavator Specs: 30- to 40-Ton Base Models

Model Operating Weight (lbs.) Horsepower Max. Dig Depth Lift Cap. (lbs.)* Arm Digging Force (lbs.)
John Deere 270C LC 62,674 177 23′ 10″ 20,643 26,067
Komatsu PC270LC-7 62,830 179 21′ 2″ 22,000 33,290
Hitachi Zaxis 270LC 62,870 173 23′ 9″ 20,700 26,000
Liebherr R934B 62,920 194 23′ 5″ 19,750 27,500
Caterpillar 325C L 63,100 188 23′ 3″ 21,150 26,200
Volvo EC290B LC 64,230 192 24′ 0″ 24,270 30,340
Link-Belt 290LX 64,400 177 23′ 5″ 21,910 25,850
Case CX290 64,725 182 23′ 5″ 21,916 28,101
Daewoo Solar 300LC-V 65,270 197 24′ 1″ 22,200 29,500
Hyundai R290LC-7 66,270 183 24′ 7″ 21,050 30,310
Hyundai R320LC-7 71,000 259 23′ 4″ 24,820 32,470
Komatsu PC308USLC-3 72,066 179 21′ 0″ 23,400 30,640
JCB JS330 72,098 219 24′ 3″ 22,248 29,547
John Deere 330C LC 72,492 246 23′ 11″ 26,089 37,396
Hitachi Zaxis 330LC 73,500 247 24′ 3″ 25,800 37,000
Komatsu PC300LC-7 73,629 242 24′ 3″ 26,400 37,040
Volvo EC330B LC 73,740 247 24′ 2″ 29,620 38,810
Daewoo Solar 340LC-V 74,700 247 25′ 2″ 26,310 38,400
Liebherr R944B 77,000 241 24′ 5″ 26,500 31,680
Caterpillar 330C L 77,113 247 24′ 3″ 26,950 36,300
Link-Belt 330LX 78,000 247 24′ 1″ 28,890 36,850
Case CX330 78,043 259 24′ 1″ 28,925 36,846
Hyundai R360LC-7 79,590 280 24′ 7″ 28,510 37,280

Source: EquipmentWatch.com

* Over the end, at 20-foot radius, at ground level

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