6/1/2001 | 7 MINUTE READ

Liberty Balance

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Strengthening. The DaimlerChrysler (DCX) people—engineers and marketers alike—refer to the car-based sport utility vehicles proffered by competitors as "cute-utes." Although they also roll out with phrases like "noble liberator" when describing the Jeep—which may be lost on an entire generation with the exception of those who have seen "Saving Private Ryan"—the point is that a Jeep is characterized by its ability to drive in places where the others would not only fear to tread, but which would be incapable of treading, even if they wanted to. And so this was kept in mind, front and forward, as the newest Jeep, the 2002 Liberty, was designed and engineered.


This Jeep go-anywhere capability doesn't come without a price, however. First of all, there is the fundamental "uniframe" construction, which is one part body-on-frame, one part unibody. Basically, there is a longitudinal rail structure to which body load points are aligned. According to Phil Jansen, director of Jeep Body Engineering, there was extensive finite element analysis (FEA) performed to help develop the necessary design, which was followed by an assortment of physical tests, including four-post shaker and what is called "AK3." That military-sounding test (which actually has its roots in the military's Aberdeen Proving Grounds) was performed for Liberty at the company's proving grounds in Arizona. The test, which also validates the suspension, is performed on roads that are so spine jarring that Jansen admits that he was able to handle only 15 minutes in the vehicle.

Although mild steel is not uncommon in underbody applications, more than 70% of the Liberty underbody is produced with high-strength steel. Additionally, there is even the use of ultra-high strength steel, a cross-car beam. Jansen explains that this is used for impact protection at the rear of the vehicle: "We want the back end to be pretty much like a rock." As the spare tire is mounted back there and the gas tank is below the rear cargo space, and as the wheels are pushed out to the edges so that there is little overhang, the ability to have something like ultra-high-strength steel providing protection, which resists deformation, is important.

(Speaking of steel: One of the previous assignments of Craig Love, vice president, Jeep Platform Engineering, was the Prowler, an aluminum-intensive vehicle. There are no aluminum body structures on Liberty. The body is steel. There are some aluminum applications, however. For example, there is an aluminum housing that is part of the front suspension. And the heads of both the 2.4- and 3.7-liter engines are aluminum.)

Also, in order to help achieve strength (for both being a Jeep and for purposes of safety) without excess weight, there is the extensive use of laser-welded tailored blanks throughout the vehicle—13 panels in all, which represent in excess of 20 ft of welds. The Liberty includes what Jansen believes is the first production application of a remote, 3D laser welding system. Instead of having the CO2 laser beam manipulated around the part by, say, a robot, this is done with mirrors.

The part in question is a reinforced swing-gate inner. Sixty-five welds are produced in 32 seconds. This work is being performed in the DCX Sterling Heights, Michigan, stamping facility. Jansen says that they had developed approaches for both spot welding and laser welding the component; thanks to a reduction in equipment (e.g., transfer devices) that the laser setup permitted, the total investment proved the case for the laser rather than traditional spot welding.

To put some of this into context: compared to the Liberty's big, older brother, the Grand Cherokee, its bending stiffness is 58% better and its torsonal rigidity is 43% better.

Smoothing. Okay. So it is rough and tough. One problem. The market doesn't necessarily want just the ability (or the perceived ability in the case of some of the competitors) to climb up the sides of mountains. Most of the time—whether this is a Jeep owner or a non-Jeep owner—people keep their vehicles on the road, not the Rubicon Trail. They don't want to do their daily commute in a go-anywhere vehicle that may be well-appointed on the inside (the Limited version can be tricked out with leather seats; there are technical-looking brushed chrome accents; buyers of either model can get a sun roof; etc.) but which feels like they're riding on a rock. So the Liberty features a newly engineered coil spring independent front suspension—which undoubtedly caused there to be gasps of disbelief among those engineers who know that "Jeep" is synonymous with solid axles—and even rack-and-pinion steering.

In the case of the front suspension (which has 8-in. of travel), the lower control arm is cast iron; the upper is forged steel; the steering knuckle is cast iron. All of which means that this suspension is more costly to make than a more conventional approach would be. But it was felt to be essential in order to attain the road manners they are looking for.

When asked about the issue of comparatively high costs associated with, for example, the current DCX minivan, and whether Liberty might have the same sort of problem (although a Sport model with V6, automatic transmission, 4 x 4 configuration, and options is priced at $21,890, which isn't particularly pricey), Craig Love says that they are looking for the opportunities to reduce costs—but "not decontent"—by doing such things as "sharing efficiencies" with both Mercedes and Mitsubishi. Among the types of items he references are control arms.

Building. The Liberty is being built at the Toledo North Assembly Plant in Ohio. It's DCX's newest plant. When running full, they'll be producing 800 units per day. The facility is staffed with some 1,900 production employees.

One of the ways that they've focused on economy of production at Toledo North is by actually using a factory simulation of the plant in a manner analogous to the way that DCX designs and engineers its products and processes. Before any cement was poured, they were able to get an understanding of what would go where—and they found not a few places where there would otherwise be expensive engineering changes involved during the actual construction (e.g., "What do you mean you need to put a support there? That's where we're going to be running some utility lines."). As a result, the cost to build is $54/ft2, less than what is said to be the industry average of $70 to $80.

As is the case by most automakers, DCX engineers used lessons learned from previous successes in equipping the plant. For example, as is the case in the Sterling Heights Assembly Plant (where the Sebring and Stratus are built), a rubber conveyor—known as a "gummiband"—is used instead of metal types. And vehicles ride on floor-level pallets during the assembly cycle. The people at Sterling Heights had borrowed the idea from Europe. And now it is being borrowed for Ohio.

One technology that Jensen points to as an example of something learned/borrowed from Mercedes is what is known as the "Sindelfingen Sealer System," which is an efficient robotic-based sealer system that places sealant on body panels where it is needed, and only there, prior to paint.

But one question: Whole new platform. Whole new plant. And some newly em-ployed processes. Does this spell trouble?

Zetsche is adamant that quality will pace the launch, that they are acutely conscious of the importance of building them right, not just building them. "Quality will be there at the beginning," he insists.

Blatant Impressionism: Driving Liberty
I don't have any idea where the Rubicon Trail is. I asked a friend. He thought that it was what Caesar crossed. I don't think that's the place. But I do know one thing: No matter what terrain would need to be traversed, the Jeep Liberty could probably take it—within reason, of course. No, strike that. I drove on a route that I am confident that only unreasonable people would willingly take, and I was told by Phil Jansen, director of Jeep Body Engineering, that I wasn't even on the really good trail. (I cringed as the Liberty tore through the trees: I could only imagine what those branches were doing to the paint. There are 10 available colors. Jansen told me there is nothing particularly special about the paint. But he noted that most Liberty owners who would drive in places like that would be in the Sport model, with sports monochromatic TPO bumpers. Which makes me wonder whether there shouldn't be a greater use of non-painted TPO and other plastics for vehicles that are going to operate in such conditions.)

I traveled on highways (and off) in the Limited Edition with the new 3.7-liter with a 45RFE electronic automatic transmission (which saw first use in the '99 Grand Cherokee) and 4WD. It was loaded with most of the amenities now figured to be necessary for Starbucks-sipping travel, such as the optional leather package and a standard CD player. (There is a more Spartan Sport model offered as well; this base unit comes with a 2.4-liter engine, five-speed manual and two-wheel drive.) The vehicle is remarkably quiet. Especially compared with one of its identified competitors (Ford Escape; Toyota RAV4; Honda CRV; Nissan Xterra: you guess which). Bottom line to the road manners: I normally drive a four-door sedan and found the Liberty to be almost as mannerly but with the boost of greater visibility.



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