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On the Mercedes C-Class

Although this vehicle fits into the “entry-luxury” category, there is little evidence of the entry part of that term in the fourth-generation C-Class from Mercedes.

It’s the fourth generation of the C-Class. Which, some might say, is a bit odd. After all, wasn’t the first one (circa 1983) called the “190”? Still, it was the C, and it sold, says Bernie Glaser, general manager, Product Management, Mercedes-Benz USA, on the order of 150,000 units. A nontrivial number. Which then leads to the second generation, the W202, which appeared in 1993. About it Glaser says that it outsold the first generation by 45%. That generation, too, passed. “The next generation of C-Classes,” Glaser enumerates, “was introduced in 2000. This was absolutely a revolution in terms of design and technology. Sales were outstanding: The third generation outsold the second generation by 65%.”

He calculates: “If you accumulate the sales of all three generations, there are more than 700,000 C-Classes on the road.”

And there is another consideration in this regard: While some of the other vehicles in the company’s fleet might get more plaudits and attention, the C-Class is the volume sedan for Mercedes-Benz. It has been the company’s top seller for six years running (2001 to 2006).

There is another consideration. If you look at the luxury vehicle category, in 2006 there were 637,429 vehicles sold in the entry-luxury niche, about 25% of the total luxury vehicle sales. This means the C-Class and the vehicles with which it competes, including the Audi A4, BMW 3 Series, Lexus IS, Infiniti G, Acura TL, and Cadillac CTS. All of the major players are well represented. “If you are looking at any volume growth,” Glaser says, “you cannot not look at this segment.”

 

Entry but not déclassé.

Although the category is “entry-luxury,” Mercedes, from the start, didn’t stint on the sedan. For example, the 190 (1984-1993) featured the company’s first multi-link rear suspension, which has been subsequently refined and replicated on all of its passenger cars (as well as those of virtually all other vehicle manufacturers). For the new C-Class, they are debuting, in the U.S. market, what’s called “Agility Control” suspension, which Glaser describes as a selective damping system that is purely hydro-mechanical in operation. Essentially, if there is input of less than 10 mm to the damper, then the ride is tuned for comfort. “As soon as you start taking the car out, driving dynamically, and the damper moves more than 10 mm, then one bypass closes in the damper and the setup becomes stiffer.” More European.

And there is another interesting number related to the C-Class: Seven. No, that’s not the number of air bags (there are six). The vehicle is available as a C300 Luxury, C300 Sport, and C350 Sport. The first two have 228-hp three-liter sixes; the latter has a 268-hp 3.5-liter six. The C300 sport is available with the newly designed NSG 510 six-speed manual transmission. But the other vehicles come with a standard seven-speed automatic, which Glaser says is the first such transmission in the vehicle’s class. One interesting aspect of this transmission is that it will skip gear ratios when downshifting—such as going from sixth to second—to facilitate acceleration yet providing smooth operation, as should be expected of a luxury vehicle. Even entry luxury.

Speaking of the transmission, the 4MATIC all-wheel-drive system, the new version that was developed for the current S-Class, is available for the C-Class. One of the differences of this system as compared with the previous generation 4MATIC is that it is compact such that it can be integrated into the seven-speed transmission. What’s more, it uses the same suspension parts as the non-equipped vehicles. Previously, it was necessary to have not only different suspension components, but also a wider transmission tunnel to accommodate the 4MATIC system. Whereas the Mercedes SUVs have a system that provides a nearly even split of torque between the front and rear during normal driving conditions, the system in the C-Class (and S-Class) is biased so that there is a 45/55 front-to-rear torque distribution, a rear bias that makes the all-wheel-drive feel more like a rear-drive setup. The system is comparatively light weight, adding just a 145-lb. premium over the standard rear-wheel-drive arrangement. 

 

“Deproliferated.”

That word, “deproliferated,” is one that Glaser uses to describe the way that the vehicle is coming to market. In the previous generation there were three models: the C230, with a 2.5-liter engine, and then three-liter C280 and 3.5-liter C350. The entry level six has been eliminated.

Another thing that was done in the previous generation (and this one continued) was, in 2005, the distinction between two categories: Luxury and Sport. One benefit of adding the Sport option (and Glaser acknowledges that if you look at the competitive set, the vehicles are generally more sporty than not) was that it took the average age of the C-Class purchaser down a few notches, from 52 to closer to 50. If one of the purposes of the C-Class is to bring buyers along to the higher-level offerings, than younger is certainly better as it increases the opportunities for purchase.

 

More than just a category.

Rather than just making minor modifica-tions to a vehicle and designating it “Luxury” or “Sport”, depending on the change, Mercedes designers executed some significant differences. Glaser calls it “a revolution.” He explains, “For the first time, Mercedes-Benz has the star integrated on a sedan.” That is, heretofore, the star has been integrated into the grilles of Mercedes coupes, convertibles, and SUVs. But in the case of the C-Class Sport, there it is, right in the middle of the three wide slats of the grille. In the case of the Luxury models, the star sits atop the hood as is befitting the stately Mercedes sedan. The Sport versions also exhibit what Glaser describes as “AMG styling,” such as the deeper front and rear aprons, rocker panels that twist toward the rear, and standard 17-in. wheels that are staggered (i.e., narrower in the front than in the back, with the standard tires on both models being 7.5-wide in the front and 8.5-in. wide in the rear).

 

Inside edition.

Inside, attention was paid to detail. Like getting rid of many of the lines that tend to make some instrument panels resemble something of a jigsaw puzzle. This is accomplished, in large part, by the robotic application of a soft polyurethane skin over the IP backing. The same process is used for the glove box and the flip-up cover for the display (which folds out of the surface of the IP with the same balletic mechanical grace of a folding hardtop), so there is overall consistency. (Speaking of backings, there is an aluminum cross member bolted to the A-pillars that supports the dash, glove box, front passenger air bag, and center console. One of its purposes is to minimize NVH. Not only is it lighter than a steel cross member—by 4 lb.—it also strengthens the structure.)

 

Materially different.

Speaking of the aluminum cross member, a few other notable materials-related elements:

  • Doors, front safety structure, front fenders and rear parcel shelf are made of aluminum
  • The body-in-white uses 70% high-strength steel, of which 20% is ultra-high-strength steel. This use is, Mercedes believes, a record quantity for a vehicle of this type.

 

Joined differently.

Back in mid-2003, a test was conducted at the Mercedes Sindelfingen plant to test a new laser welding system that deploys a robot to help manipulate the location of the beam. It was called “RobScan.” The process was tested on some 25,000 S-Class components, where the laser seams were used in place of spot welds. Not only were the engineers determining production feasibility, but also the welds were tested for their physical performance user various conditions. Based on the work that was done, it was determined that RobScan would be used for the production of a passenger car series. The C-Class, which happens to be produced in Sindelfingen (and elsewhere) may be the vehicle that was targeted back in ’03. There are approximately 640 RobScan welded seams on the door, side wall, and rear body areas of the C-Class.

In addition to which, there is plenty of adhesive used, as well. There is more than 196 ft. of bonded seam on the C-Class.

Overall, the new vehicle is 17 lb. lighter than the previous model and yet its torsional rigidity is 13% higher.

 

Calculating.

None of this was achieved by chance. Mercedes produced 280 prototypes for the C-Class. But in addition to those physical artifacts, they created virtual prototypes for the car that were used for a number of development applications, like crash tests. The C-Class was crashed some 5,500 times—on a network that consists of more than 1,500 processors. The digital model of the C-Class consisted of some 1.9-million elements; the impact calculations for a crash consisted of 320,000 million operations (hence the exceedingly large network). In addition to crash, the 2,130-gigabyte digital car model was used for other development operations, including handling, NVH, durability, thermal verification, thermal and electrical energy management, climate control, powertrain, and aerodynamics. One of the more interesting assessments performed in the virtual space was that of climate control. Factors that have to be taken into account are vehicle speed, temperature, level of sunlight, and humidity. Mercedes engineers developed what they call “TIM,” a computer model. (The name is an acronym for the German for “thermophysiological occupant model.”) TIM simulates the human body in 14 areas and takes into account blood circulation. TIM was linked with other programs, for example one that divides the interior into 7.8-million spatial units and measures the air flow, temperature, and other parameters at each point.

Entry-lux? All this sounds pretty full-on despite the market positioning.