Product Report: Efficiency-plus

Slated for introduction in wheel loader models next year, ZF’s Efficiency Package driveline combines five elements to claim an up-to- 15-percent fuel reduction:

  • Ergopower transmission, with five speeds instead of the four of previous models, reducing noise and allowing comfortable shifting. The transmission also offers additional opportunities for electronic driveline management.
  • Ergolockup, an electronically controlled converter lock-up clutch that directly transfers engine torque to the axles already in low gears.
  • Ergotraction, which enhances the engagement and disengagement of the power shift differentials.
  • Ecotraction, which automates the optional axle disconnect at the transmission.
  • And the company’s compact Multitrac steering axles.

“Our Ergolockup ensures that the torque converter – which is basically not very efficient – only operates when it’s required,” says Hermann Beck with ZF’s Construction Machinery Systems division. “One example of when it’s needed would be driving a loader bucket full force into a pile of rocks, which requires maximum torque. But when you’re just moving the loader from one area to another, the lock-up clutch closes to provide a direct drive link between the engine, transmission and axle. At this point, it’s similar to a mechanical transmission, which results in added fuel efficiency.”

While lock-up clutches are common in trucks, Beck says this is their first appearance in construction machinery. The clutch prompted changing the Ergopower transmission from a four-speed to a five-speed unit because of the relatively high gear step on the four speed. “Since the lock up is engaged all the time, we were able to do this better with a five speed,” Beck says.

Ergotraction manages the loader differential locks, engaging the differentials locks in wheel loaders and the interaxle differential locks in dumpers. Previously, the differential locks were only engaged when they were needed. Today, they are always engaged unless they would disturb the operation. This gives a loader 100-percent tractive effort, and contributes to the fuel saving advantages of the entire package.

Ecotraction automatically disengages a wheel loader’s all-wheel drive when not required, such as driving on a flat surface. The automatic axle disconnect has several advantages, reducing fuel consumption and tire wear, and improving driving performance. “You lose a lot of efficiency if you have permanent all-wheel drive,” Beck says.

The Multitrac axles are equipped with integrated, wet multi-disk brakes. The precise gear meshing leads to reduced noise, and the system allows connection of an electronic driveline management and direct transmission mount.

Wheel loader driveline systems make up the largest segment – 31 percent – of ZF’s construction machinery business. Other significant segments include wheeled excavators (14 percent), backhoe loaders (13 percent) and articulated dump trucks (10 percent).

Also new from ZF
North America represents the largest chunk of ZF’s construction equipment business, making up about 37 percent of company’s worldwide revenues in this market. Some additional products on the horizon include:

Ecomix II transmission: Aimed at concrete mixers of up to 13-cubic-yard drum capacity, these CML 10 transmissions are 50 percent smaller, 20 percent lighter and quieter than the previous generation. The unit offers increased output bearing strength, increasing the life of the bearings by 40 percent.

HC 85 hydrostatic driveline: The 1 HC 85 and 2 HC 85 compact construction equipment transmissions incorporate actuators and sensors that enable continuously variable speeds up to 26 mph with no gear shifts. The crankshaft radial piston motors, with piston seals, offer reduced oil leakage and fuel consumption. Due to the integration of hydro motors into the transmission system, there is no requirement for external pipes and valves.