| August 02, 2012 |
Is it time for a new wheel loader?
Advanced electronics, drivetrain refinements make the case for a new machine
By Marcia Gruver Doyle
As you’ve waited for the economy to turn, your wheel loaders have aged, and now those machines are perhaps two generations behind what’s currently in dealer order books. Buying a low-hour used machine – if you can find one at a decent price – is always an option. But the improvements in the newest generation go beyond new paint. As one manufacturer says, “It’s an exciting time for wheel loaders.”
Here are some reasons it may be time to bite the bullet and step up to a new loader in the 4-to-<6 cubic yard reference bucket size:
Tier 4 Interim engine
You’ll pay a higher price for new loaders and the primary culprit is the engine. These engines generally require large diesel particulate filters, low-ash oil and ultra-low sulfur diesel (see sidebar). But they also come with advanced electronics that allow a host of refinements in air flow rate, fuel injection, combustion and aftertreatment functions. These, in turn, optimize performance, reduce emissions and fuel consumption and provide advanced diagnostic capability. (Note: some machines in this size category are still transitioning to Tier 4 Interim engines.)
“Today’s wheel loaders are burning 8 to 10 percent less fuel than seven years ago, which has been primarily achieved through electronic controls, drivetrains and hydraulics,” says Rob Marringa, brand marketing manager, Case Construction Equipment.
Idling also has gained attention in the past five years. Cat’s Engine Idle Management System, for example, kicks in when an operator applies a parking brake, reducing the idle rpm even further. The new JCB 457 has both a low idle feature and an engine shutdown mode, which starts after a pre-determined idle period.
“With the powerful engine control modules, we were able to do a lot more integration with transmissions, axles, linkage, buckets, cabs, really the whole system,” says Cedric Gold, wheel loaders marketing consultant, Caterpillar. “Transmissions, for example, can be smaller with a torque-based logic, so the machine is always going to be in the right gear for an application.”
Loaders now have more capable telematics systems, and the Big Brother concerns of yesterday have evaporated, says John Chesterman, product marketing manager, four-wheel-drive loaders, John Deere. Using Deere’s Service Advisor Remote, for example, a dealer can remotely update a machine’s software.
The information is just so good on all sides – customer, manufacturer and dealer – that many manufacturers offer telematics as standard. “Generally, whatever the dash can read, Komtrax can convey,” says Armando Najera Jr, wheel loader product manager, Komatsu. For instance, the Komatsu WA 380-7 monitor now displays fuel consumption, information that wasn’t available in previous generations.
While contractors remain slow to integrate telematics into their office systems (see Why the disconnect? story on page 35), manufacturers continue to preach the benefits. Telematics, says Najera, allow you to monitor a host of inputs, including idle time, which in wheel loaders can reach 40 to 50 percent, depending on the application. “Think beyond fuel savings,” he advises. Monitoring and reducing idle time helps equipment last longer. “If you save 200 hours a year off your service meter reading, not only will it help you stretch the time between service intervals, it means that three to five years down the road you have a machine with lower hours and a higher resale value.”
As the electronic sensors become more sophisticated, they program loaders to shift smoother, which translates to less wear on the drivetrain, says Najera. “Drivetrains still have the same basic components, but it’s how you manage it. It’s now a function of the hardware and the software. Because the machine has more sensors, we have more data. We know more about them and how to make them better.”
Manufacturers are using a number of automatic transmission variations.
The Case 1021F and 1121F models, for example, have hydro-mechanical transmissions, which Case says offers the advantages of hydrostatic drive, along with the durability of conventional mechanical transmission, adjusting the mix of power delivery depending on travel speed. The hydrostatic pumps and motors work at lower speeds, mix with mechanical gears at mid-range speeds and then converts to mechanical gears in the highest speed.
Volvo says its OptiShift technology reduces fuel consumption by 15 to 10 percent over standard drivetrain configurations. OptiShift, now standard in the L150G, uses the lock-up function during a larger part of the work cycle. When an operator wants to change direction, OptiShift senses the loader’s speed, direction and accelerator position and slows down the machine by applying the service brakes automatically. This results in faster loading cycles, reduced powertrain load, smoother direction changes and lower fuel consumption, according to the company.
Lock-up torque converters have become common. Deere says they’ve had strong acceptance since the company put them on its larger wheel loaders in 2008. “They help save fuel, especially in high speed applications in load and carry,” Chesterman says. “Plus there’s a big performance benefit in ramp climbing.”
Cat’s K series drivetrains have single clutch speed shifting. The machine senses torque going through the drivetrain and will put the machine in the right gear to match demands. “This is a big change from five to seven years ago,” says Gold. “A lot of operators like to manually shift, but auto shift offers a large fuel savings.”
LCD monitors, rear-view cameras, and smoother controls top the improvements here. One example is Komatsu’s dash-7 cabs, which have a 7-inch LCD monitor panel with an easy-to- navigate menu system.
In-cab rear cameras are becoming common, assisting operators in seeing over the hood, which in some models became larger to allow room for emission reduction components. Loader controls are now electronic pilot control.
“Electrohydraulic controls have decreased in-cab hydraulic lines and increased cab space,” says Nick Tullo, product marketing specialist, Volvo Construction Equipment. Another benefit: seat-attached control units have replaced control towers. They also allow in-cab adjustments of boom and bucket detents, eliminating the need to manually adjust detents.
Cat’s 966K has low-effort electrohydraulic joystick steering system with a force-feedback feature that automatically increases joystick effort as ground speed increases. “This completely eliminates the need for a steering wheel,” says Gold. “Even though it’s an electrohydraulic system, it feels like it’s mechanically turning the machine left and right. The operator can have full control of the machine without the steering wheel.” Sensors on the lift and tilt functions allow operators to set the attachment position from inside the cab.
Manufacturers now have on-demand load sensing hydraulics. “We also offer simultaneous lift and tilt, so there’s no priority of lift over tilt, and it allows smoother operation,” Gold says. Cat, for example, gives operators the ability to set the dump height, return to dig and work tool attack angle from inside the cab. “Let’s say you’re dumping to a 5-foot conveyor. This let’s you set the dump height to 7 feet, instead of all the way to 9 feet,” Gold says.
The IntelliDig system on Kawasaki’s new 85Z7 and 95Z7 balances rimpull and hydraulic force, metering out power, as the bucket moves into a pile.
Manufacturers have increased cooling capacity, offering wider cooling fin spacing and auto-reversing fans to keep the radiator clean. Service intervals have been extended, says Deere’s Chesterman, compared to machines that debuted in the mid-2000s. Engine oil changes moved from 250 to 500 hours, and in-tank hydraulic fuel tank filtration allows more capacity, moving change intervals up to 4,000 hours.
On it’s K Series loaders, Cat improved on the electric and hydraulic service centers it first featured with its H Series. Grouping these centers allows faster maintenance and repair, Gold says.
Komatsu has added swing-out rear fenders and coolers to improve serviceability access to the engine and cooling components.
Several new loaders are in the wings:
Deere’s 644K hybrid, introduced at ConExpo in 2011, will debut a production model later this year. The machine will feature an electric drive, with a single motor and generator, that allows the 6.8-liter engine to run at a constant 1,800 rpm engine speed, quickly generating full power. The constant engine speed also allows the hydraulic response to remain steady, instead of varying with engine speed. “This will help newer operators easily gain the crowd force needed to get a full bucket out of the pile,” says Chesterman.
The next machine in Komatsu’s lineup will be the 5- to 6.8- cubic yard WA470-7, which will have the same cab as the WA380-7, and is expected to be out later this year.
The Cat 966K XE, which debuted at Intermat in April, will reach North America by early next year. The XE, which Cat says can deliver up to 25 percent fuel efficiency improvement, uses a hydraulic variator instead of a torque converter for reduced heat generation under severe rimpull load. When under heavy loads, the continuously variable transmission consumes roughly half of the energy compared to a conventional transmission.
In the Interim …
The diesel particulate filter on Tier 4 Interim engines requires a regeneration – which removes soot from the filter. A number of manufacturers have made this a passive function, requiring no operator input. “When you go into auto regen, it pops up on the monitor screen, and then goes into regen automatically as long as you keep operating the machine,” says Deere’s John Chesterman. A complete DPF cleaning will be required around every 4,000 hours.
And if it’s not a convenient time for a regen – for instance, if you’re working in an area with a lot of airborne debris and you want to avoid the elevated exhaust temps – Chesterman says you can take it out of automatic mode, and do the regen at another time.
There will be an additional operational consideration as manufacturers move into Tier 4 Final. Several manufacturers have announced they will be changing from an exhaust gas recirculation to selective catalytic reduction emissions strategy, which requires the use of diesel emission fluid. Case is already using SCR for its Tier 4 Interim solution on its loaders, including the 1021F and 1121F. Doosan also chose SCR for its DL350. Since on-highway trucks have used DEF since 2007 (see article on page 45), the DEF infrastructure is largely in place, although it does mean your field trucks will need to carry an additional fluid.
Four factors affecting loader fuel efficiency
Instead of just monitoring fuel use, says Caterpillar’s Cedric Gold, consider a loader’s total fuel efficiency, or how much work you can squeeze out of each gallon. This can be affected by the following:
Machine application. If you’re doing load-and-carry work, consider how far the loader needs to go and what material – and gradation – is being moved.
Operator technique. Make sure your operators know all the capabilities of the machine, including auto shift. Become familiar with rolling resistance and its impact on productivity – the smoother and cleaner the operating floor, the faster an operator can go, with less up and down on the throttle, requiring less fuel.
Remember there’s a balance. Reducing idle time has become a mantra, but if there’s only one truck being loaded, why speed up the cycle just to quickly go back to idle? Just because a machine can load a truck in 22 seconds doesn’t mean you have to max out its capabilities if your job doesn’t require it.
Look at machine configuration. Gold cites Caterpillar’s Performance Series buckets as an example. Designed to reduce loading time, the buckets have an optimized shape and side curves to reduce friction while penetrating material.
Don’t forget the operator
John Chesterman with John Deere tells about a site visit where he saw a young operator speeding through his load cycles, barely getting a half-full bucket. “I just spent 15 minutes with him to show how to load the bucket,” he says. “His production went up 200 percent and he was a lot happier.” The experience prompts him to urge owners to remember one of the most critical components of loader productivity: the operator. “Mentor your new operators. Show them how to use all the features on a loader, including lock-up torque converters and ride control.”
ROUND UP -- iModels with 4-to-6-cubic-yards reference bucket capacity include:
Compared with previous models, Volvo’s L110G and L120G wheel loaders offer a 25 percent increase in lifting force, a 15 percent increase in breakout force and up to a 5 percent increase in fuel efficiency. Both loaders are powered by a Volvo six-cylinder, turbocharged, Tier 4 Interim V-ACT engine that provides 256 horsepower to the L110 and 268 horsepower to the L120G. The front axle is fitted with a hydraulically-operated differential lock that transfers 100 percent power to the wheels, reducing wheel spin and improving traction in soft or slippery conditions. Two stronger, variable displacement, load-bearing axial piston pumps allow higher working hydraulic pressures, enhanced control of the load and attachments, as well as higher breakout force, faster lifting and tilt functions.
The 1021F and 1121F models are designed for quarry, aggregate and truck-loading applications. Case was the first manufacturer to use the selective catalyst reduction Tier 4 Interim emissions strategy on loaders. The 296-horsepower 1021F and 320-horsepower 1121F offer joystick steering, four selectable power modes and a rearview camera. The loaders are available with hydro-mechanical transmission, which adjusts the mix of power delivery based on travel speed and offers the advantages of hydrostatic drive with the durability of a conventional mechanical transmission.
Kawasaki 85Z7 and 90 Z7
Kawasaki’s new 85Z7 and 90Z7’s new body designs improve visibility from the cab. Features include Tier 4 Interim engines, new powertrain components and hydraulic and electrical systems. An Isuzu engine provides the 85Z7 with 221 horsepower while the 90Z7 has a 280-horsepower Hino engine. Use of variable displacement piston pumps in an open-centered, excavator-style hydraulic system saves on fuel and improves the overall feel and response of the hydraulic system. The “IntelliDig” system balances rimpull power and breakout force when digging tough materials. Both models have a high degree of operator customization, allowing the operator to set power settings, lift arm kickout settings, the declutch setting and how the transmission shifts.
Liebherr’s L550-IND has a redesigned front linkage. With precise parallel movement over the entire lifting range, the L550 provides a clear view of the work area and produces a more equal amount of torque throughout the lifting cycle. Machine applications include pipe handling, small log handling, operations where a large light material bucket is necessary and utility operations where the use of forks is needed throughout the day. The L550-IND features the Liebherr hydrostatic driveline and is powered by the Liebherr D934S A6 four-cylinder diesel engine.
JCB has replaced its 456 wheel loader with the new 457, featuring a Tier 4 Interim, 8.9-liter Cummins engine. Delivering 250 horsepower to the 457, the engine’s Economy mode reduces engine output for lighter duties while saving up to 6 percent fuel. The engine incorporates a high-pressure common rail fuel injection system, exhaust gas recirculation and a variable geo-metry turbocharger. The 457 offers more loading capacity and a tipping point increased by 3.3 percent over the 456, resulting in an extra quarter of a ton of bucket capacity. The JCB Smooth Ride System can be activated at any speed, allowing operators to tailor it to individual site requirements.
Doosan has increased the horsepower of its DL350 to 271 with a five-cylinder, Tier 4 Interim engine that uses selective catalyst reduction technology to offer as much as 16 percent increased fuel efficiency over previous models. The DL350’s lift capabilities have been upgraded, giving operators the ability to set upper and lower limits for both the lift arm and bucket stop positions from inside the cab. The machine has a dump height of 10 feet and can be equipped with optional electric steering to decrease operator fatigue. A joystick has been added to the left armrest to allow operation without the steering wheel. A centralized monitor inside the cab displays engine rpm, coolant temperature, fuel level, machine warnings and other data.
Caterpillar’s new 267-horsepower C9.3 ACERT engine powers its 966K wheel loader, which has a new operator station, electro-hydraulic steering with either joystick or steering wheel control, Cat Performance Series buckets and a more efficient drive train. The cab features a wider, front-hinged door along with left- and right-hand sliding windows, both of which can be opened and closed while seated. The machine can be equipped with the Cat Fusion coupler, specialty buckets, pallet forks, rakes, material handling arms and plows.
Hyundai’s HL770-9 has a fuel-efficient, low-noise, Tier 3 Cummins QSB6.7 engine with three engine modes. The 277-horsepower engine is electronically controlled for optimum fuel to air ratio and clean and efficient combustion. Other features include a redesigned cab with standard automatic AC/heat, heated rear-view mirrors, hands-free phone, personal storage space and AM/FM radio with MP3 player ports. A 5.7-inch color monitor mounted on adjustable swivel-mounts allows easy machine control. The HL770-9 also comes standard with Hi-mate, Hyundai’s remote management system providing access to service and diagnostic information on the Internet.
Komatsu’s WA380-7’s 191-horsepower, Tier 4 Interim SAA6D107E-2 engine offers up to a 10-percent decrease in fuel consumption, compared to the WA380-6. SmartLoader Logic provides optimal engine torque for the job required and saves fuel by automatically decreasing engine torque when it’s not needed. Komatsu’s large capacity torque converter with lock-up comes standard, providing improved acceleration and hill-climb ability and a higher top speed, all with lower fuel consumption. In addition to a 7-inch display monitor, the loader comes with the Komtrax telematics system.
Deere’s PowerTech 9.0-L IT4 Tier 4 Interim engine uses cooled exhaust gas recirculation technology to meet emissions standards while powering the 744K with the same 304 horsepower as Tier 3-equipped 744K. It features Deere’s Quad-Cool system with a multi-function color LCD monitor displaying onboard diagnostics. The NeverGrease pin joint option keeps joints tight longer, extending pin life and eliminating daily greasing.
LiuGong’s 856IV is powered by a 206-horsepower Tier 4 Interim Cummins engine for big load-carrying power that allows faster cycles on the jobsite. The 856IV comes standard with limited-slip front and rear differentials for better performance in difficult terrain.
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