Equipment Type

Tier 4 Regulations Prompt Wheel Loader Enhancements

The countdown continues for 2011 EPA emissions requirements on mid-sized machines

August 01, 2011

Anyone who manufactures, purchases or uses construction equipment knows the fourth phase of nonroad EPA air-quality regulations hit in January for engines larger than 175 horsepower. Compared to Tier 3 levels, Tier 4-Interim standards require a 90 percent reduction in PM and a 50 percent decrease in NOx. Some companies, such as Case, Caterpillar, Deere and Volvo, took advantage of World of Concrete and Conexpo venues to unveil their Tier 4-I solutions. But others have yet to officially introduce their cleaner-burning equipment.

In January, Case launched its first round of F Series loaders with the 721F, 821F and 921F, and finished the line in March with the 1021F and 1121F. All feature Tier 4-I Fiat Powertrain engines that range in horsepower from 179 to 320. Although the middle three machines fit into the 200- to 300-horsepower focus of this article, all of them use selective catalytic reduction (SCR) technology to meet 2011 emissions standards.

“We chose to go with selective catalytic reduction because it has been around for decades and is well proven in our engine lineup in particular,” says Tim O’Brien, marketing manager. “And it allows us to package the engine and cooling system in the same space as we did before. Plus, we were able to maintain our narrow one-piece, raise-up hood on all those models for its good visibility and serviceability. 

“Horsepower is much the same,” O’Brien says, “but the power you feel in the torque is higher and fuel efficiency is much improved. The SCR and the engine choice itself allowed us to gain nearly 10 percent more fuel efficiency. There are some other advantages with SCR, too. One is engine response. In a wheel loader application, more than any other type of machine, they’re on and off the throttle and there’s no constant engine speed. You want that throttle to respond quickly to be able to get the lift arms up and meet the target accurately and quickly for high production. With SCR, the engine breathes very free, and it allows us to make the engine response even faster than Tier 3. So the machine has better torque and feels much more powerful.”

An optional 5-speed lockup transmission is offered on 721F, 821F and 921F models only. It comes with a feature called PowerInch, which is an intelligent declutch that includes braking, and it adjusts automatically through the computer controller to the different inputs such as the torque requirements. On the larger 1021F and 1121F loaders, Case has an “industry-first” option for a hydro-mechanical transmission (HMT). Other F Series options include joystick steering, upgraded axles, automatic locking differential, and a rearview camera, which hasn’t been offered before. In addition, Case’s four selectable power modes—carried over from the earlier series—have been reformulated for even better fuel efficiency and power.

Caterpillar also took advantage of the Conexpo platform and announced its K Series loaders—the 950K and 962K (not available until early 4Q), 966K and 972K—which feature new Cat ACERT engines meeting Tier 4-I emissions standards. An upgraded ADEM 4 control module manages the combustion process; and new high-pressure common rail fuel system allows precise injection timing for a clean, efficient burn, the company says. The Cat Clean Emissions Module is mounted on its own platform above the engine and contains a diesel oxidation catalyst, diesel particulate filter, and Cat Regeneration System—the latter of which can be set to take place automatically so it does not interrupt the work cycle.

Drive trains have been optimized with the new engines to improve digging power, acceleration and performance. The machines have new torque converters that are matched with the engine power curve to save fuel while delivering power increases. In addition, they have new transmission shift logic for downshifting into first gear. Now the downshift occurs based on the torque requirements instead of ground speed, which enables operators to use the automatic transmission mode in first through fourth gears, Cat says. Also, transmission speed shifts are significantly smoother due to the new shifting strategy that reduces torque losses while shifting. The result is faster acceleration, better ramp-climbing performance, and improved shift quality.

Also launched at Conexpo was Komatsu’s WA380-7, marking its first Tier 4-I wheel loader, but just under our horsepower range at 191. Although marketing manager Mike Gidaspow wouldn’t give an exact date, he said the general platform and features of that machine will be carried over to the larger wheel loaders. He said it would be a Komatsu engine with variable geometry turbocharger (KVGT) and will use a Komatsu diesel particulate filter (KDPF). The machines will also require changes in the hood to accommodate the need for increased cooling capacity.

Currently, Komatsu models falling into the 200- to 300-horsepower range are the WA430-6, WA470-6 and WA480-6, with bucket capacities from 4.1 to 8.0 cubic yards. All feature Tier 3 Komatsu engines with Electronic Heavy-duty Common Rail fuel injection system. The machines also feature upgraded torque converters.

“With the change in torque converter,” says Gidaspow, “we obviously had to make some other improvements with the axles and everything connected to it. The reason that torque converter provided better acceleration, hill-climb ability, and better fuel consumption was because it was designed for the Komatsu engine and power-train components on these machines.”

Still in transition from Tier 3 to Tier 4-I official releases, Volvo offers two F models and one G model in our focus group. Models L110F and L120F will be upgraded to G models in the fourth quarter and will offer much of the same design changes as the recently introduced L150G, L180G and L220G. The L150G, at 295 horsepower, comes equipped with the Volvo-patented OptiShift system, which includes the reverse-by-braking (RBB) feature and a lock up torque converter.

“With the RBB system, the transmission actually goes into neutral and the engine goes to an idle,” says Blaine Pressley, segment director. “And as long as you keep your foot on the throttle, then the brakes take over in changing the direction of the machine. Just about 1 to 2 mph before it’s complete with the direction change, then the engine and transmission re-engage. We’re really excited about it because first of all, it’s going to save a lot of fuel; and second, it saves a lot of wear and tear on the drive train. And with the lock up torque converter, we help the customer save even more fuel in load-and-carry applications.

“An important feature of our Tier 4-I engines is that Volvo wheel loaders will not require any stoppage of the equipment when operators do the regeneration for the Tier 4 requirements,” Pressley says. “Some other brands of equipment may have to stop to perform regeneration, but with Volvo’s system, the operator performs regeneration while continuing to work. All that is required is the push of a button—it tells you on the screen to do it—then it just regenerates and you continue to run the machines just like always. So we consider that a real advantage because it doesn’t cost you any production time.”

What the future holds

All manufacturers agree that fuel-efficiency innovations will be key in the quest to combat ever-rising fuel costs. Many have addressed the problem with their new engines and improved torque converters as well as engine-shutdown features and power mode options. Other trends include more operator comforts within ergonomic operator stations and joystick steering as well as automated features, GPS grade-control setup, and advanced diagnostics capabilities for ease of maintenance and increased uptime.    

Manufacturers also say that popular features that used to be options will eventually become standard. For example, Volvo’s 150G now comes standard with an in-cab setting for boom kickout, bucket kickout and return-to-dig. The smaller L110G and L120G will also have these features as standard equipment. Additionally Volvo includes the OptiShift system as standard equipment for sizes L150G and larger.

Komatsu says once it sees the vast majority of customers are ordering a particular option, it will make it standard in the future. Just as radios and air conditioning used to be options years ago, these days they typically come standard. Stay tuned for the latest wheel-loader developments.

 
 

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