An all-weather blast

This cutaway view shows Auburn Gear's ECTED. The coil rides on a ball bearing, which in turn rotates with the differential case while the coil remains stationary.

Traversing loose sand, a twist ditch, and a simulated ice/asphalt roadway demonstrated the muscle of various four-wheel-drive systems at a recent SAE International sponsored ride and drive program at the Eaton Corp. Proving Grounds in Marshall, MI.

A compliment to SAE's "Advancements in 4Wheel Drive Vehicle Systems" Toptec (TOPical, TEChnical) symposium, the event focused on 4x4 offerings from seven automotive suppliers.

The latest iteration of the Haldex limited-slip coupling contains three primary parts: a hydraulic pump driven by the differential speed between the axles, a wet multi-plate clutch, and a control valve with corresponding electronics. Debuting on the 2003 Volvo XC 90, the second-generation system's control valve is the key differentiator from the first-generation product. "It was a stepper motor-actuated valve, and now it's a magnet-actuated valve. So it's a quicker reaction from open to close of the control valves, which carries over to more vehicle dynamic possibilities," said Edo Drenth, Control Software Specialist with Haldex Traction Systems, a division within the Sweden-headquartered Haldex Group.

New Venture Gear spotlighted a torque-limiting progressive all-wheel-drive (AWD) system that incorporates thermal overload protection. The NV 900 AWD system on the all-new Saturn Vue limits the rear axle torque to 1800 N•m (1330 lb•ft) maximum. "It's a passive system, meaning there are no electronic controls," said Fred Porter, Chief Engineer of Systems Integration for New Venture Gear in Troy, MI. Although purpose-built for the Saturn SUV, a modified version of the system is slated for vehicle applications in MY2004.

A vehicle equipped with American Axle & Manufacturing's SmartBar, an electronically controlled stabilizer system, tackles the twist ditch.

Eaton's ELocker differential, standard fare on the new Hummer H2, provides 100% lock. "It's a brand new product—an electric locking differential rear axle that can be driver-controlled or computer-controlled," said Ralph Holmquist, Chief Product Engineer of Current Products for Eaton Automotive Torque Control Products Division in Marshall. A locking differential front axle application is product-ready. "We can do ELocker for front, and we will do so for the aftermarket," said Holmquist.

Auburn Gear's production ready ECTED (Electronically Controlled Traction Enhancing Differential) is exclusively controlled via current to the coil. "The unique thing about our device is it's designed to be operated by the vehicle control system, meaning variable control," said Andy Schneider, Sales Manager-Automotive Products for Auburn Gear in Auburn, IN. With a compact design envelope, "the system drops in to many existing 4x4 axles as well as passenger cars," Schneider said.

The MY2004-05 is tagged as the production application timeframe for the patent-pending SmartBar electronically controlled stabilizer system. "We've found by testing, including a 45% hill with obstacles, that a vehicle equipped with the SmartBar system and the TracRite electronic front and rear differentials gives you the ultimate off-road capability," said Jeff Kincaid, Executive Engineer with American Axle & Manufacturing (AAM).

Key system components include the disconnect assembly, actuator unit, and the left and right stabilizer bar. The system uses AAM technology such as proprietary lateral retention collars and a patented "plug in" link to stabilizer bar attachment method. "We have applications in development that have front- and rear-stabilizer SmartBar as well as front-only SmartBar," said Kincaid.

Eaton's electronic locking differential rear axle goes through a workout; the technology is also available for the front axle as well as the aftermarket.

The 2002 Ford Ranger FX4 uses a Torsen T-2R rear differential. T-2R also is available on the aftermarket. "We've been selling it about a year," said Rick Barnes, Project Engineer at Zexel Torsen, Inc. in Rochester, NY. Although not yet production-available, the Ranger FX4 features a Torsen T-2 front differential. "It adds capability to the front because under normal conditions if you lose traction on one wheel, you'd lose the benefit of four-wheel drive on the front," said Barnes. (The T-2R and T-2 differentials are used on a Ranger FX4 that competes in an off-road racing series.)

NTN's Lock-On-Demand transfer case, similar to a system used on all-terrain vehicles, is not yet a production-vehicle application. "It's a roller clutch that has complete automatic controls of the engagement and disengagement of the roller clutch. All the torque is transferred through the roller clutch," said Russell Monahan, New Product Development Supervisor at the NTN Technical Center, Inc., in Ann Arbor, MI.

- Kami Buchholz

Behr's climatic wind tunnel

The monitor shows warm and cold airflows as Behr test engineer Michael Wells demonstrates specialized equipment.

The $34-million Behr America, Inc. headquarters/technical center in Troy, MI, houses various test sites, including a climate-system calorimeter test cell to simulate underhood and interior cabin conditions, a condenser calorimeter test stand, and a radiator wind tunnel that is used for testing heat exchangers.

The focal point of the two-building complex is a $15-million climatic wind tunnel, slated to go online in early 2004. "A sister climatic wind tunnel in Stuttgart, Germany, became operational in early 2001," said Markus Flik, Member of the Board of Behr GmbH & Co. "It's still the most modern climatic wind tunnel in the world."

The Michigan wind tunnel will accommodate passenger cars as well as light-duty and commercial trucks. Dynamometer testing is possible up to 800 hp (600 kW). Wind velocity can reach speeds of 125 mph (200 km/h) in temperature extremes of -30 to + 50°C (-22 to +122°F). "The wind tunnel will allow us to precisely test and measure the performance of Behr components under all conditions that affect the vehicle," said Josef Kern, Behr's Senior Vice President of Engineering.

The Behr America tunnel will be the first climatic wind tunnel in the U.S. with solar simulation capability. Artificial lighting can mimic drives through a tunnel, cloudy conditions, full sunshine, and sunrises and sunsets. Climatic wind-tunnel tests use information gleaned from in-vehicle positioned thermal test dummies. Data collected from 16 sensor points on a thermal dummy's artificial skin provides engineers with a resultant surface temperature. Engineers use climatic wind-tunnel-test data to evaluate how air temperature, air speed, and solar radiation would impact humans. "It's a very good tool for getting some very good, repeatable, objective data for (determining the) subjective comfort of passengers," said Flik.

In addition to the climatic wind tunnel, the building will also house a hemi-anechoic chamber for vehicle and component testing (opening the fall of this year), a reverberant room for component testing (opening summer 2003), and a soak room, which can be used for conducting static tests such as windshield defrosts and engine cold starts.

"The main purpose for building this facility is for product development," said Joachim Raimann, Chief Engineer for Testing at Behr America. "But we've already had climatic wind tunnel test time inquires from OEMs.

- Kami Buchholz

Mobility for all

The new patent-pending rear wheelchair/scooter securement system invented by Gary Talbot and Rick Prusinowski requires no holes drilled into the vehicle. It will be an optional system for MY2004 GM minivans.

Vehicles that meet the needs of certain people while serving the wants of all people summarizes the design for mobility philosophy. "If we make a vehicle easier to get in and get out of for someone with a disability or for the senior population, then it's better for everybody," said Gary Talbot, Manager of Mobility Engineering for General Motors Corp.

In the future, human factor issues will rank high on vehicle buying priority lists. According to census data, the U.S. had 76 million people age 50 and older and 54 million people with disabilities in 2000. "You'll be looking at a third of the U.S. population in 2020 who will be 50 and older," said Jeff Roegner, Manager of Sales and Industry Analysis and Mobility Communications for GM.

For more than 20 years GM has worked on a variety of issues pertinent to seniors and people with disabilities. In 1995, for instance, GM founded the Paragon Team to better grasp their needs. Today, the UAW-GM Paragon team—encompassing active and retired employees—provides consumer clinic feedback.

Recent corporate realignments have put mobility and other issues on the fast track. "All along GM's vehicle product development there are regimented gates that we use to get involved with the product execution team," said Talbot. "In the past for the Mobility Group, it was always a matter of where are they in the process and how can we get involved."

The expectation is that future production vehicles will transform various mobility-orientated design ideas into reality. One such example is a seat bottom that extends beyond the rocker panel, "So it acts like a permanent assist seat," said Talbot. "It's the little differentiators that accommodate a broad audience that will really give GM a competitive advantage. Down the road, you're going to see these 'little nuggets' that the Mobility Group has influenced."

Ron Pniewski, GM North America Vice President of Planning, concurred that in the past the Mobility Group has been a bit removed from the vehicle product development loop. "Now they've been brought more into the mainstream. And it doesn't slow things down," said Pniewski, "it makes it faster."

The improved vehicle development process involves up-front collaborative portfolio planning, in which considerations such as internal requests, projected profit and volume, manufacturing issues, and technology/safety aspects are accessed before a vehicle design moves to vehicle program initiation.

"We've been on a continuous improvement path with our product development. This (advanced vehicle development process) just steps it up," said Pniewski. The revised approach is intended to produce great vehicle designs, eliminate non-value-added work, reduce development times, impede unnecessary inputs, and downstream reworks as well as bypass group-to-group hand-offs.

"In essence, we're managing a virtual organization since most of the critical players associated with the up front work are parts of the bigger product development organization," said Mark Hogan, GM Group Vice President, Advanced Vehicle Development. "What has changed is our ability to make the right product decisions and execute them faster through streamlined decision making and better organizational focus."

- Kami Buchholz