| November 01, 2011
A new breed of Cat
The D8T dozer, K-Series wheel loaders and E-Series excavators point the way to a safer, more productive future
While its vocational truck has grabbed the spotlight this year, Caterpillar’s engineers in charge of off-road equipment have been anything but quiet.While some of you may have briefly glimpsed the new earthmovers at CONEXPO-CON/AGG, in September the company gave the industry press two full days to explore the new iron.
There’s more here than we can cover in the pages of one issue of the magazine, so we’ve added a special digital section to this article that goes into more detail about the individual machines. Go to www.equipmentworlddigital.com for more photos and specs on the new dozer, wheel loaders and excavators. Next month we’ll continue this series with a look at the revamped G-series artics and rigid frame trucks.
The D8T track type tractor, the K-Series wheel loaders and E-series excavators bring to fruition several years of design refinements and new technology, and they all share some common goals:
• Fuel efficiency. As with most manufacturers, Cat has refined both the mechanical systems and the computer chips that control the engines, hydraulics and driveline components to optimize the amount of work you do for the amount of fuel spent. As a general rule, fuel savings can range anywhere from five to 15 percent, depending on the machine and the application.
• Operator comfort. Tricked out cabs aren’t meant to spoil operators, but to keep them sharp and productive. Cat says the goal is to enable the operator to be as productive in the last hour of the day as he was in the first. To do this they’ve reduced noise and vibration in the cabs, recalibrated the drivetrains for smoother shifting and more automatic shift points; and in the case of the K-Series wheel loaders, added an innovative new joystick control option.
• Safety. Walking around on the upper reaches of many older machines can sometimes feel as precarious as rock climbing in Yosemite. But standing anywhere you need to stand on these three new Cat machines you feel flat footed, stable and safe. New tread plate gangways wrap around these access points and hefty waist-high grab bars surround these areas and add to the security. The standing platforms are ample in size too, so big booted guys don’t have to worry about getting their feet tangled up when turning around. There’s even a platform you can stand on to manually clean the windshield on the new wheel loaders.
• Visibility. Taking a cue from today’s pickup trucks, Cat equipped the machines in oversized mirrors. Nearly every machine also now comes with a rear view camera that shows you a wide-angle, real time image of what’s behind you on an in-cab monitor anytime you hit reverse. Lighting packages have also been put on steroids with extra bright halogen and high intensity discharge lights. The lights also turn off on a delayed switch, giving you time to climb down from the machine and walk away before they go dark.
• Built to rebuild. In tough economic times more contractors are opting to rebuild older machines rather than buy new. Cat is staying out in front of this trend by designing all the major components for remans and multiple lives. Sustainability factors into this, too. For example, 96-percent of the materials used in the new wheel loaders are recyclable (as defined by the ISO-16714 process), and the machine itself is built from a minimum of 25-percent recycled material.
Cat’s clean air solutions
To meet Tier 4 interim requirements, Cat’s engines in the new machines control combustion by using multiple injection fuel delivery, optimized turbocharging and a new intake air management system. NOx is held in check by returning a portion of the cooled exhaust gasses back into the cylinder for combustion.
Downstream from the combustion chamber the aftertreatment unit uses what the company calls the Cat Clean Emission Module. This combines a diesel oxidation catalyst, diesel particulate filter and a regeneration system.
Like most DPF/DOC systems, the Cat aftertreatment will purge itself of soot (called “regeneration”) under most operating conditions by burning it out of the DPF. But when additional regeneration is necessary the Cat Regeneration System will elevate the exhaust temperatures to oxidize soot within the DPF.
The system fires up automatically, without requiring the operator to do anything. The computers and sensors embedded in the system can get quite clever at choosing the best time to regenerate. When soot build up within the DPF reaches 30-percent capacity it starts looking for regeneration opportunities within the operating parameters of the machine. At 70-percent capacity it looks harder for opportunities. In any event, it will find that sweet spot in the duty cycle and activate automatically without interrupting your work. But the operator can initiate regeneration manually if he so desires and at the end of the day he can select the “key off regeneration” option as well.
Regeneration can momentarily raise temperatures within the DPF in excess of 1,000 degrees, so an insulating package is available for machines that work around flammable material.
Every drop of fuel counts today and small gains in big machines add up to considerable savings over time. That’s the theory that’s driving the design of Cat’s Performance Series Buckets that come standard on the new K-Series wheel loaders. The buckets are designed for application-or material-specific uses to get faster fill times, better fill factors and better material retention.
They have slightly longer floors with wider openings, improved strike planes and convex sidebars. Improved wear resistance on the corners and side cutters extend the life of the buckets. The buckets are also being more closely matched to the capabilities of the machine so you’re not overtaxing the machine with a too heavy bucket or running too many cycles with a too small bucket.
For a more comprehensive look at the D8T, K-Series wheel loaders and E-Series excavators check out our digital version of the magazine at www.equipmentworlddigital.com.