Equipment manufacturers break wheel loader applications into two broad categories: production and utility. Production work is repetitive loading using a V-pattern (or Y-pattern) cycle or a load-and-carry cycle. The loader may run constantly throughout a work shift. Utility work involves more varied use – including digging, loading and lifting – and may have more idle time.
The challenge for OEMs is to create features that are of value to all customers, regardless of which category they fall into. This influences design choices for everything from lift linkages to cab glass to hydraulic reservoir placement. All this while also meeting the demands of Tier 4 Final emissions regulations.
Among the common improvements are transmissions with lock-up modes, auto-idle and auto-shutdown, and various work modes to match performance to the demand. While each has multiple and disparate benefits, they all work to improve fuel efficiency. Joystick steering, in addition to or in lieu of a steering wheel, is also becoming more widely available. Ride control damps oscillations during travel to improve operator comfort and minimize bucket spillage.
More than fuel efficiency
Current wheel loaders provide big improvements in fuel efficiency over previous models. Case Construction Equipment, for example, says their Tier 4 Final 821F and 921F models have up to 30 percent better fuel efficiency than previous models. An available 5-speed lock-up transmission plays a role in fuel savings, but the benefits of that optional transmission extend beyond a reduction in fuel consumption, says Philippe Bisson, Case brand marketing manager. “This transmission improves acceleration, travel speeds and climbing power, and by eliminating power loss, it can increase fuel savings by as much as 8 percent,” he says.
The five-speed transmission also includes Case Powerinch, which allows low ground speeds for precise approaches to targets while maintaining high engine speed to maximize hydraulic power. This provides optimal control and accuracy in tight loading areas, regardless of engine speed or grade, which is ideal for short cycle loading.
Caterpillar’s 950M and 962M loaders have lock-up torque converters and locking front differentials. Refinements to Eco mode operation preserve more performance while further reducing fuel consumption. The 950M has a Z-bar linkage that also provides parallel lift capabilities, offering the best of both designs. And these loaders can run four hydraulic functions simultaneously instead of the more typical three functions. Lucas Sardenberg, wheel loader marketing consultant for Caterpillar, says sweeping is an example of an application where four functions prove helpful. The operator can move the broom side-to-side without articulating the machine.
Volvo uses several technologies to attain reductions in fuel consumption of up to 18 percent in their L110H and L120H wheel loaders. Reverse by Braking (RBB) automatically reduces engine RPM and applies the service brakes when the operator changes directions. This reduces stress on the drivetrain while conserving fuel. RBB is part of OptiShift, as is a lock-up torque converter. An eco pedal provides greater push-back, encouraging operators to keep the engine at its most efficient speed.
Product manager Eric Yeomans says three features on Volvo loaders make maintenance much easier. The entire aftertreatment assembly can be swung away with the removal of a few fasteners to improve service access. Rapid Oil Exchange (ROX) evacuates used oil from the engine, including the used filters, and then refills the system, including the new filters, with fresh oil. This makes for cleaner oil and filter servicing and ensures filters are pre-filled to prevent pressure loss upon startup. Grouped service points facilitate daily service checks. The rear axle cradle has lubricated-for-life bushings and bearings.
Tier 4 Final
The 457 is JCB’s first Tier 4 Final wheel loader. Where its predecessor used an 8.9-liter Cummins engine, the 457 has a 7.7-liter engine from MTU. Horsepower and torque are both up despite the drop in displacement, and Peter Gallagher of JCB says the smaller engine is a better fit for the loader. “We leveraged the continuing march toward greater power density.” And the Series 1000 in-line 6-cylinder meets Tier 4 Final regulations without a DPF.
On its Tier 4 Final loaders, Komatsu uses SCR, which requires diesel emissions fluid, or DEF. The DEF tank and lines are heated, and DEF is pulled from the lines back to the tank at shut-down to further protect against freeze damage. DEF consumption is about 2 percent of fuel use, helping Komatsu meet their goal of fluid neutral or better (using the same or less total fluids, fuel and DEF, as the fuel consumption of previous, non-SCR models). DEF level is shown on the cab monitor.
Komatsu’s Tier 4 Final machines also have Komatsu DPF. More than 98 percent of KDPF regeneration is done while the loader keeps working.
Pay attention to aftertreatment
Wheel loaders in this size class have engines from 141 to 271 horsepower. EPA emissions standards are different for engines up to 174 horsepower and engines of 174 to 751 horsepower. Flexibility in the laws allows some OEMs to continue offering Tier 4 Interim machines even though Tier 4 Final went into place for all engines effective January 1.
One result of this is that aftertreatment technologies vary. Because aftertreatment system types can affect operation and maintenance, it’s important to understand the design and requirements of a specific system.
OEMs have worked to minimize the impact of aftertreatment. Kawasaki, for example, uses a Cummins QSB6.7 in their 70Z7 loader (3.7 to 4.2 cubic yard). The engine is rated at net 168 horsepower. Cooled EGR and a variable geometry turbocharger control NOx and PM while a diesel oxidative catalyst (DOC) controls the soluble organic fraction of particulate matter. The DOC requires no servicing.
“Our 70Z7 loaders have a maintenance-free, regeneration-free emission system,” says Gary Bell, vice president and general manager, KCMA Corporation. “There is no need to perform periodic manual regenerations. There is no DPF and therefore no need to remove a DPF for periodic cleaning or exchange. With no DPF there is no need for diesel emissions fluid. The emissions control system of the 70Z7 requires virtually no maintenance.” The loaders meet Tier 4 Interim regulations, and will be offered throughout 2015 and possibly into 2016, says Bell.
Location, location, location
Some features are the result of reconfiguring traditional layouts. On their 821F and 921F loaders, Case moved the cooling module from behind the engine bay to behind the cab. Bisson says this placement of the high-efficiency cooling cube reduces clean-out intervals and susceptibility to thermal events.
John Deere relocated the hydraulic oil tank from behind the cab to the frame under the left-side ladder that leads to the cab. This was done to make room for the SCR hardware under the hood while preserving rearward visibility.
With their CommandPlus cab in the 457 loader, JCB moved the A pillars to match the width of the rear of the cab, opening up a panoramic view to the front. The right side A pillar holds all switches and auxiliary controls while all main controls are seat mounted and move with the seat as it’s adjusted.
Doosan reconfigured the steering columns of loaders in this size class to give more room for operators’ feet and legs. Joystick electric steering is an option that provides steering of the loader without using the steering wheel. This type of steering can reduce operator fatigue especially in repetitive applications like V or L pattern loading. Doosan uses outboard planetary gears and outboard brakes to decentralize heat load for better thermal management.
Mike Stark, Doosan’s wheel loader specialist, points to the flexibility in spec’ing their loaders. “The DL220, DL250, DL300 and DL350 all have Z-bar linkages; the DL250 is also available as a toolcarrier with a parallel lift linkage. The DL250 and larger models are available as high-lift models with an additional 12 inches of dump height.”
On-board weighing systems
In a production environment, payload weighing systems for loaders help increase productivity and efficiency, especially where accurate truck loading and material tracking is critical. Tom Barnum, product consultant with John Deere, says, “These systems can generate daily productivity reports, tracking material moved by product type, customer, or location, and ensure trucks are loaded to their maximum capacity while not being overloaded. Because these systems weigh dynamically, without having to stop the loader to calculate the weight, cycle times are decreased.”
Deere’s primary system is the Loadrite L2180. It is a factory-installed option available on all utility and production class loaders. L2180 sends payload information via JDLink, Deere’s telematics system. That information, including cycle times, production output, and more, is then available online. Using an on-board printer the L2180 can issue scale tickets. On model 724K (4.0 to 4.75 cubic yard) loaders and smaller, Deere also offers a more basic weigh system, the Embedded Payload Scale (EPS). “EPS is an entry-level scale system that will calculate bucket weight and truck weight,” says Barnum, “but it will not generate any reports or downloads.”
John Frame, technology consultant with Caterpillar, says OEM systems make full use of OE sensors, electronics, and telematics. Compared to aftermarket systems, this can improve reliability and may reduce costs. Cat’s Production Measurement Payload Weighing System uses the loader’s integrated touch-screen display; reports are available in that display and in VisionLink, a secure, web-based application developed by VirtualSite Solutions, a joint venture between Caterpillar and Trimble. Other features of the on-board system include last bucket tip-off and low-lift weighing.
Typically the dealer will calibrate the system as part of initial set-up and subsequent fine-tuning can be performed by the operator using the loader’s Simple Cal mode. “Since fine-tuning is quick and straightforward, it should be performed periodically to ensure that the best accuracy is being maintained,” says Frame.
Operators should strive to be smooth and consistent. While the system will filter out noise in the form of pressure spikes, accuracy is improved when fewer such spikes occur.
While some customers may opt for a factory-installed on-board weighing system, many will want to add a system to an existing loader or manage the installation of a system to a new loader as an aftermarket add-on either by the dealer or by a third party. Simon Rush, global marketing communications manager for Trimble Loadrite, offers these tips to customers.
“Consider your budget, existing requirements, and future requirements. Most people have an adoption curve that starts with payload optimization and moves on to other features as they become comfortable with the technology. Operators may also have preferences for a particular style or brand. Using similar technology throughout the fleet will make training and data management easier.”
Rush says the key considerations are:
- Accuracy. Loader scales can achieve +/- 1 percent accuracy, but since a small deviation in accuracy can quickly affect profitability periodic reference checks are recommended.
- Support. For maximum uptime, scales should be installed by a skilled specialist technician and locally serviced at regular intervals.
- Extended features. Including the ability to total payload for a day or longer period, automatically add bucket payload without operator intervention (via a preset lift arm/boom position), multi-attachment selection and more.
- Productivity improvement analysis. Managers can analyze payload data to improve productivity. Tagging data fields, such as product, operator, customer, and project, allowing tracking of material through the operation.
- Connectivity. Communication between machines via onboard scales, the truck scale, the office, and mobile devices is increasingly valuable as it allows for near-real-time information on operations, downtime, and potential issues.
RMT Equipment, located in Blainville, Quebec, is the North American distributor for the Italian company VEI. Marc Lefebvre of RMT says customers for their aftermarket systems fall into two categories. The first wants a simple system with high accuracy. The goal is to avoid over- or under-loading trucks.
Either customer can make use of VEI’s standard USB data transfer or opt for an RF or Wi-Fi modem. Information can be saved locally or uploaded to an online account, which RMT offers for $15 per month. Installation and service are available from a network of master distributors.
A different approach
“We are the anti-value-added company,” says Al Quinn of SDLG. The Chinese manufacturer, represented in North America by Volvo, offers basic models with few frills. Transmissions are powershift, not automatic. Hydraulic systems are open center, not closed. Cabs are comfortable, but not plush. Cab glass is flat panel, not curved. Some models have dry, not wet brakes.
“The basics are in place,” says Quinn. “The machines are reliable and meet capacity needs, such as full-turn tip and lift capacity. We use Deutz engines produced in Germany and installed at our plant in China. But while on-board weighing systems, telematics and other add-ons can be installed by our dealers to meet customers’ needs, mostly we’re selling to customers who don’t receive value from those features.”
Who are these customers? “Snow removal is big for us. Or the contractor who drives his dump truck to his yard, hops out of the truck and into the loader, fills the truck, parks the loader and drives away. Anyone who puts fewer than 1,000 hours on a loader in a year. He says that with a price point 35 percent lower than other brands, customers get a new machine with a full warranty and the leasing, financing and other options associated with new equipment for the cost of a 3- to 5-year old used machine.