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Chrysler's digital trailblazer

Chrysler's digital trailblazer

Auburn Hills, MI--Engineering drawings dominate the gray walls of the windowless "war room" in Chrysler's mammoth Technical Center. A few depict late changes in the company's Concorde and Intrepid vehicles; a few more display the layout of its Bramelea, Ontario assembly plant.

But when Chrysler engineers and executives sit at the war room's long center table, they don't gaze at the drawings. Instead, their attention focuses on a computerized projection screen at one end of the room. There, they can watch the company's redesigned LH vehicles take shape in front of their eyes. Every major LH engineering decision has taken place in front of this screen. Every component--from the tiniest bolt to the largest piece of sheet metal--can be viewed on it. The paper drawings on the walls merely lend occasional visual support.

Welcome to the new world of automotive design, Chrysler style. By taking one of the boldest steps in recent automotive history, the company has changed its vehicle engineering process and eliminated the once-critical need for paper drawings.

While that may not seem dramatic at first glance, the extent to which Chrysler has employed the concept is extraordinary. For the LH program, the firm has stored some 1,900 drawings in its computers, represented by about 11 million digital polygons. Using this database, its engineers can check for static and dynamic interferences between all parts on the vehicles. They can apply the CAD data in supercomputer-based crash tests, create stamping dies and assembly tooling, and examine the flamefront inside an engine's cylinder. Moreover, they have stretched their digital engineering process to include all of the company's parts suppliers and its tooling suppliers.

Cultural change. When Chrysler engineers set out to redesign the popular LH vehicles in 1995, their mission statement did not call for digital design. "We wanted to preserve the things that we'd done right on the earlier LHs, and improve on the areas that had gone wrong," recalls John E. Kent, Jr., executive engineer for vehicle development in Chrysler's large-car platform.

Executives identified five broad features that they wanted to preserve in the redesigned LHs--performance, value, craftsmanship, styling and packaging, and its "fun-to-drive" nature. On the other side of the ledger, the company called on its engineers to eliminate the early LHs' problem areas--road noise, harshness, and, to a lesser extent, difficulties with the cars' defroster and headlights.

At the same time, Chrysler wanted to "push cab-forward to the next generation." That meant lowering the hood line, extending the base of the windshield, and taking out some of the front overhang. To meet new emission requirements, they also needed to shift the catalytic converters from under the car to under the hood.

In short, engineers faced a packaging nightmare. Cab-forward had been a challenge when Chrysler engineers first implemented it in the 1993 models. Now they needed to make the hood area lower and sleeker than ever before. At the same time, they needed to add more to an already crowded underhood area.

The solution to this seemingly impossible task, however, was already in the works. The first part of it had been dropped in place half a decade earlier. Chrysler's platform teams had already played a key role in the stunning success of the LH sedans, Viper, redesigned minivans, and Dodge Ram trucks. The platform concept brought together design, engineering, manufacturing, assembly, procurement, accounting, finance, and other individuals in cross-functional teams, then colocated them within a few feet of each other.

Suddenly, engineers who had previously known only their own part and its supplier name were forced to see the bigger picture. They learned about their particular part's manufacturing, assembly, cost breakdown, and its role within an overall sub-assembly. "In this culture, every engineer becomes an entrepreneur in their area," notes John C. Miller, general manager of large-car platform engineering for Chrysler. And, undeniably, the platform concept was successful.

Cultural change two. But as the LH redesign was launched, Chrysler engineers faced another cultural change: 100% electronic design. Like many companies, Chrysler had long implemented CAD techniques in the design of various components, but it never made electronic design a universal edict. "For years, all of us designed parts in CAD," Kent recalls. "Then we would hand the design off to someone who would cut a 3-D wood model. So we realized we were wasting our time."

Worse, like GM, Chrysler had designated no single CAD system. (Ford, in 1995, picked SDRC's I-DEAS as its single system.) Instead, pockets of loyalty to different CAD systems existed around the company. Within a single department, engineering teams sometimes used two or three separate programs. "Everybody had the system du jour," Kent says.

But as the LH redesign was launched in February 1995, all that began to change. Chrysler demanded that platform teams focus on a single CAD system, namely CATIA. "The most important thing that Chrysler did was to say, 'We are focusing on one and only one computer system,'" Kent says. "The time benefits that you get from working off a common set of data are incredible."

Chrysler, however, wasn't content to enjoy the time benefits gained by having 6,000 of its own engineers work off a common set of data. The company also wanted its suppliers to work off CATIA. That was an especially far-reaching decision, in light of the fact that Chrysler purchases about 70% of the content of every car from suppliers. (By comparison, Ford purchases about 50%, GM about 30%.)

"We told all our suppliers: 'Not only do we want you in full partnership, we want you to be electronically linked,'" Miller says. "We told this to the part suppliers and the tooling suppliers."

Digital payback. For Chrysler, the pain of this sweeping cultural change was worth it. From the very outset of the new LH program, engineers quickly saw the advantages.

Instead of building clay models of the new LHs, then digitizing the clay, designers did it the other way around. They digitally styled the vehicle, repeatedly adding and subtracting features after executives viewed its image on the war room's huge projection screen. Digital styling models were always done in three dimensions, and the on-screen projections were so detailed that they could even see how sunlight reflected off the vehicle's sheet-metal panels. When an agreement was reached, they finally built a model in clay, but only as a concession to those who felt more comfortable with its physical presence.

"Doing it this way, we can present 10 different design alternatives without the cost of building 10 different models," says Robert M. Trecapelli, advanced CAD CAM research engineer for Chrysler. "If one of the executives says, 'I like the front headlights in that model and the tail lamps in this other model,' then they can come back the next day and we can show them what it looks like."

Airing it out. Some of the greatest paybacks of digital design, however, were fully realized during the engineering process. In their effort to curb the LHs' noise-vibration-harshness problems, Chrysler engineers focused on air induction noise. Their goal: to redesign the air intake manifold and make it sound more pleasing to the ear.

A few years ago, that would have meant building a prototype, running tests, modifying the design, creating another die, and building another manifold. At best, most vehicle programs allowed enough time for engineers to go through four or five such iterations.

On the LHs, however, engineers went through more than 1,500 iterations, and they did it in six months less time than it had taken using the old methods. Employing computational fluid dynamics programs, they electronically altered the engine's noise characteristics, then demonstrated the new sound for executives back in the war room.

To test designated prototypes in the lab, they merely sent the digital data to a CNC machine and cut the "flow boxes" for the part. Result: They not only improved the noise characteristics; they improved air flow quality. The company's new aluminum block engines have benefited from the design, offering more torque per size than any other engines in their class.

Digital assembly. Chrysler also benefited from the link between computer-aided design and manufacturing. Unlike the conventional process, where human intervention had always made it difficult to pinpoint the source of manufacturing troubles, each step in this process was defined by hard data. As a result, it was easier to spot problems when they arose.

That was especially important in the construction of a new aluminum hood; Chrysler had never made one before. With the ability to quickly locate potential problems, they no longer needed to repeatedly recast the part each time something went wrong. "The ability to do this from a mathematical point of view guaranteed that the quality would be there in the hood," Trecapelli says. "And that will make our launch go smoother because we won't be chasing problems 10 weeks before volume production."

The biggest advantage of the digital process, however, was in its ability to store all of the cars' data in one central location. This enabled engineers to better understand the relationship between components, and to consider serviceability issues before they ever committed to building a part.

Using a process called Digital Model Assembly, Chrysler engineers brought together data from four key areas of the vehicle: body, powertrain, chassis, and interior. A special computer program, known as Chrysler Data Visualizer, worked in conjunction with CATIA to let engineers see if components interfered with one another or if they shared the same space in any way. The visualizer lent extraordinary speed to the once-mundane process of interference checks. In one case, while checking for interferences between sheet-metal components, the system performed 8,646 checks in 17 sec.

As a result of the digital assembly process, the team eliminated the need for so-called "bucks." Within the auto industry, bucks have traditionally served as a crude way to check for interferences early in the design process. Engineers typically built bucks from whatever was at hand: fiberglass, sheet metal, styrofoam, even shoe boxes. Using bucks that matched the size of their proposed component, they attended meetings where they claimed space in their automobile.

In the past, engineers usually rebuilt their bucks as the design progressed. On the 1993 LH vehicles, for example, they used a total of 16 bucks. In contrast, the new LH used none.

LH team members say that digital assembly streamlined the development process in hundreds of instances. When they attached the LH's chassis pallet to the car's body, they gained a full appreciation for the advantages of digital assembly. The chassis pallet, which typically contains the engine, suspension, fuel system, fuel line, and a host of other components, seldom attaches successfully to the body on the first try. But on the new LHs, it attached with no interferences during the first five minutes.

"It was so easy that we brought it back down and reattached it, just to make sure we weren't doing anything wrong," Miller recalls. "In 1993, when we tried to deck the first car, we were still trying three months later."

Far-reaching gains. The advantages of digital assembly are also transferable from one program to another. Recently, when Miller considered using an LH engine on the Chrysler Sebring convertible, he asked Arthur Anderson, supervisor of advanced chassis powertrain, to do an interference check for him.

"He asked me to do the check on a Thursday afternoon," Anderson recalls. "By Friday morning, we had compiled a list of all the parts that would need to be changed." Anderson adds that such interference checks previously took about three months.

Digital assembly also provides engineers with the capability of seeing not just how the parts fit together in the vehicle, but how the subsystems will be assembled. For the assembly of the vehicle's floor pan, for example, digital assembly shows the number of welds and the number of robots needed, along with other tooling and fixtures.

None of this could be accomplished without the common availability of digital data. Nor could it be realized without a culture that eliminates boundaries between design, engineering, manufacturing, assembly, and procurement.

Experts readily admit that such cultural changes can be wrenching at times. "It's difficult to deal with because most people want compartmentalization and rigid structure," notes David Cole, director of The Office for the Study of Automotive Transportation at the University of Michigan. "But these days, companies need to be flexible and agile." If they aren't, he warns, they may be left behind.

Computational tools the key. For Chrysler, the benefits of the new process are numerous. It enabled the company to produce the Concorde and Intrepid in 31 months, compared to 39 for the 1993LH vehicles.

More importantly, it allowed Chrysler designers to give the vehicles the look they wanted, and enabled engineers to solve earlier LH problems. Computer analysis, for example, allowed them to improve sealing and NVH. Computational fluid dynamics further reduced air noise. Better air flow through ducts boosted defroster performance. And the headlights, once criticized as ineffective because they were too small, suddenly dominated the front of the car. The company now takes pains to show the large, stylish headlights in publicity photos.

Engineers say that none of this would have been possible without the new process. The tight packaging, they claim, would have been an impossibility. "If we didn't have the computational tools and the DMA, we couldn't have executed this design," Kent declares.

For the consumer, the time and money saved means more product value, Miller says. "If we can take the cost out of a part, then we can take that cost and put it where it can yield more value for the customer," he explains. "That's our approach to designing cars."


When Chrysler engineers re-designed the popular LH sedans, their challenge was to keep the features that worked best, and eliminate existing weaknesses:

KEEP CHANGE
Appearance Road noise
Throttle response Vibration
Acceleration Defroster operation
Aerodynamics Headlight performance
Interior volume
Trunk volume
Craftsmanship
Steering
Handling


LH engines benefit, too

by Charles J. Murray, Senior Regional Editor

Chrysler's LH vehicles weren't the company's only products to benefit from its new emphasis on digital design. The company's new V-6 family of aluminum block engines were developed in 98 weeks at a cost of about $625 million, possibly making it the shortest engine program in recent automotive history.

Typical automotive engine development programs take about 21/2 years and cost about a billion dollars.

Despite the lower cost and faster development time, Chrysler says that the new engines offer higher torque than any other engines in their class, while still offering good efficiency. The key: Computer analysis enabled engineers to model nearly every aspect of the engine, from flamefront propagation to air induction. "We couldn't have achieved that performance and efficiency any other way," notes John E. Kent, Jr., executive engineer for vehicle development in Chrysler's large-car platform.

The company's engine line includes three models: a 2.7l, 24-valve dual overhead cam V-6; a 3.2l, 24-valve V-6; and a 3.5l, 24-valve V-6. The 2.7l will appear as the standard engine in the 1998 Dodge Intrepid and Chrysler Concorde. The 3.2l engine will power the Dodge Intrepid ES and the Chrysler Concorde LXi, while the 3.5l will be used exclusively on replacements for the Chrysler LHS and Eagle Vision.


Timeline for design

February 1995
Chrysler launches LH redesign

November 1996
Chrysler unveils aluminum block engines

January 1996
First "soft tool" vehicle

September 1997
First volume production LH sedans

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