MB SLR McLaren Comprehensive Overview for US

Press Release

Mercedes-Benz SLR McLaren
Comprehensive Overview for the US

Tire Pressure Monitoring

The SLR comes with a tire monitoring system that has pressure sensors built into the inside end of each tire valve. As the wheels spin, the information is transmitted by radio to antennas inside each wheel well. The signals are processed by a central control unit that can distinguish the signals from each wheel, and information on each wheel is shown on a central display in the cockpit.

ESP STABILITY CONTROL

ESP electronic stability control and SBC electronic braking are integral parts of the SLR’s safety and dynamic handling systems. Since the electronic braking system uses a high-pressure accumulator to hold brake fluid at a pressure of 2000 to 2300 pounds per square inch, this power means that the ESP system works even better than on ESP-equipped models with conventional brakes. Thanks to even faster and more finely metered brake impulses from the high-pressure accumulator, ESP can stabilize a skidding vehicle at an earlier stage. Engineers developing the SLR thought it might be a challenge to adapt the stability control system to the car’s distinctly sporty performance while maintaining their usual safety standards. However, with its sophisticated sensors and light-speed reactions combined with sheer braking power, the presence of the electronic braking system actually made it easier to fine-tune ESP for a very sporty driving style that allows moderate oversteer and understeer when driving the SLR, but without compromising active safety. Mercedes-Benz invented ESP stability control in the 1990s and debuted the system on its more expensive 1996 models in the U.S. The high-tech feature is now standard equipment on all models.

ESP Works Like a Mind Reader

ESP calculates every microsecond if the car is going exactly in the direction it is being steered. If there’s an appreciable difference between what the driver is “asking�-- through the steering wheel -- and what the vehicle is doing, the system corrects with split-second speed by applying one of the left or right-side brakes, even before the driver may sense any changes. ESP uses steering wheel angle and wheel speed to calculate the path being steered, and it gets signals about lateral “g� forces and “yaw� to measure what the car is actually doing. (Imagine turning a model car on a toothpick stuck down through the roof – that’s yaw!) Whenever it senses understeer, ESP increases brake pressure to the inside rear wheel. With an oversteer tendency, it increases brake pressure to the outside front wheel. Unlike traction control, ESP is effective during acceleration, braking and coasting. The system enhances driver control and helps maintain directional stability in turns as well as when driving straight-ahead, including on uneven surfaces and over patchy snow, ice or gravel.

ELECTRONIC BRAKING

In the SBC electronic brake system -- another Mercedes-Benz invention -- light-speed electronics replace many of the mechanical and some of the hydraulic parts. A powerful micro-computer oversees the system’s operation by processing information from a series of sensors and control units. The pedal is no longer connected hydraulically to the wheels (except for a backup system that operates the front wheels conventionally in the unlikely event of an electronics problem). The brake pedal and master cylinder are merged into a single operating module (a conventional vacuum-powered brake booster isn’t needed), and this module primarily transmits brake commands to the microcomputer via electronic impulses.

The Nerve Center – Electronic and Hydraulics Working Together

The centerpiece of the electronic braking system brings together the microcomputer, wheel pressure modulators, a hydraulic pressure reservoir and an electrically-driven hydraulic pump. The operation of this assembly highlights the interdisciplinary beauty of the system – while hydraulics still provide the sheer braking power, electronics make it work faster and better than ever:

1. The electronic braking microcomputer calculates exactly the right brake force for each wheel by processing signals from the pedal unit and from sensors all over the car. It considers wheel speed data from the ABS system, steering angle and cornering g-forces from the ESP system, as well as signals about the engine braking effect and which gear is engaged from the engine-transmission microcomputers. The result of these complex calculations is instantaneous brake commands, which means maximum braking and driving stability.
2. The high-pressure reservoir holds the hydraulic oil or brake fluid that powers the system under 2000-2300 pounds per square inch of pressure. The microcomputer controls an electric pump and regulates hydraulic pressure throughout the system. The overall result is much shorter response times compared to conventional brake systems. This system also provides full braking power even when the engine is off.
3. Four wheel pressure modulators regulate brake pressure at each wheel based on everything processed by the microcomputer. Each wheel is braked individually to ensure the greatest possible driving stability and optimal deceleration. A pressure sensor for each wheel modulator, for the reservoir and for the pedal unit help the microprocessor to monitor everything.

Braking Around Corners Like Never Before

If braking is ever necessary in a turn, conventional systems apply the same brake pressure on the inside and outside wheels. However, the SBC electronic brake system increases pressure to the outside wheels and reduces it on the inside ones. This takes advantage of the vehicle’s natural weight transfer during cornering and increases vehicle stability, in part by reducing the tendency to lock the inside wheels when braking in turns. To provide this valuable left-right brake proportioning, the microcomputer processes signals from the ESP steering angle sensor and lateral G-force sensor. In a similar way, front-rear brake proportioning is also part of the system’s built-in algorithm. To prevent dangerous over-braking on the rear wheels, the majority of the braking force is placed on the front wheels during high-speed braking. At low speeds and when braking lightly, the system places more of the braking pressure on the rear wheels, ensuring smoother response and more equal wear on the brake pads.

Built-in Brake Assist for Faster Emergency Braking

Among the greatest benefits of the Mercedes-Benz electronic braking system is the ability to respond to driver and vehicle behavior as well as make use of the extremely fast buildup of brake pressure. If drivers switch their foot quickly from the accelerator to the brake pedal, the electronic brake system recognizes the early signs of an emergency situation and reacts accordingly. First, the microcomputer “primes� the system by raising brake pressure in the connectors and pressing the brake pads lightly against the disks. As soon as the brake pedal is pressed, full-power braking is applied with the help of the high-pressure reservoir. In practical terms, this means that alerting the system and then applying full pressure shortens the stopping distance from about 80 mph by some three percent!

A Comfortable Pedal

To simulate the familiar pedal feel of conventional brakes, Mercedes engineers utilize the tandem hydraulic cylinder that operates the front brakes only in the event of an electronic failure. In normal operation, this master cylinder is hydraulically “decoupled� from the rest of the system.

Staying Dry in the Rain

Wet brake discs can mean an instant of terror until the wheels make one turn and the brake pads squeegee a film of water from the disks. In wet weather, the electronic brake system provides short, imperceptible brake impulses to wipe off the water, ensuring fast brake response. This automatic drying feature works whenever the windshield wipers are on.

SLR BODY

The body of the Mercedes-Benz SLR McLaren is as high-tech as the rest of the car. Most of the car is made of carbon fiber composite – the entire body shell, its gull-wing doors, the hood and underbody structures at the front and rear. Overall, the SLR is about 30 percent lighter than a comparable vehicle with conventional steel construction. While this extremely strong yet lightweight material originated in the aircraft and aerospace industries, carbon fiber has proven itself dramatically on the world’s top race tracks. As Formula 1 developers have begun used carbon fiber crash structures over the past several years, the F1 racing discipline has seen a dramatic reduction in serious injuries from collisions.

Half the Weight and Four Times the Energy Absorption

Carbon fiber is half the weight of comparable steel parts and 30 percent lighter than aluminum! What’s more, carbon fiber absorbs four to five times more energy than steel or aluminum in a collision. Mercedes-Benz takes advantage of this extraordinary energy absorption by installing a two-foot longitudinal member made of specially designed carbon fiber on each side of the SLR front end. In a head-on collision, the fibers in these conical crash members shred from front to rear with absolutely consistent deformation, ensuring steady deceleration. With their ever-changing cross-section, the conical carbon-fiber crash members not only have predictable energy absorption but also a weight advantage, since the design uses only as much material as is actually needed. Each of the longitudinal members weighs only 7 ½ pounds.

The First Production Car with Carbon-Fiber Crash Structure

The carbon-fiber crash members are bolted to an aluminum sub-frame for the engine, and at the front, they connect to the body shell by means of a cross member and a flat sandwich panel, both made of carbon fiber composite. As a result, the SLR is the world’s first production car with a front crash structure made entirely of carbon fiber. At the rear of the car, similar carbon-fiber crash members, along with a hefty cross member, handle energy absorption in the event of a rear impact.

Four Years of Careful Development Work

The goal of engineers from the Advanced Design department at the Mercedes-Benz Technology Center and from DaimlerChrysler Research was not only to design crash members with unprecedented passive safety, high strength and low weight, but also to develop the first automated manufacturing processes for carbon fiber. Prior to the SLR project, carbon fiber parts for race cars and airplanes alike have been made by hand – an extremely time-consuming process. Early steps included the first-ever development of a special algorithm for calculating crash dynamics on carbon fiber. Sophisticated computer simulations were crucially important to fine-tuning the crash structure. At the same time, materials experts were testing the calculations by conducting precise drop-tests of carbon fiber models. Over a four-year period, design details of the SLR crash members were gradually defined.

The First-Ever Automated Production of Carbon Fiber

To transform the world of carbon fiber from slow hand work to automated production, Mercedes-Benz materials experts took a careful look at the textile industry. They ultimately took conventional production methods of sewing, knitting, weaving and braiding fabrics and adapted them for making high-performance carbon fiber. For example, the web of the SLR’s front crash members is formed by laying several layers of carbon fiber on top of each other and sewing them together by machine. Then the piece is cut into shape, folded into a double-T profile and inserted in a plastic braiding core, which in turn is clamped into a special braiding machine. Each crash member is braided together with 25,000 extremely fine carbon filaments that are simultaneously unwound from 48 reels. This technology allows carbon fiber to be braided around the core at specific angles to create the right contour, and several layers are even laid on top of each other in certain areas to get the right thickness. A computer-controlled tufting machine then joins the inner web to the braid of the longitudinal member, after which the plastic core is removed. Then the pre-formed crash member is trimmed to the correct size and injected with resin. Several patented processes were developed to ensure good repeatability and short cycle time – critical factors for series production. Making the complex carbon-fiber structure of the SLR’s front crash members takes just 12 minutes, a clear demonstration of the potential offered by this innovative manufacturing technology.

SLR Uses Advanced Sheet Molding Compound Method

The rear shelf of the new SLR provides another example of new techniques used by Mercedes-Benz for producing carbon fiber components. Although it’s a complex shape with several openings, the rear shelf is manufactured in one piece using a new Advanced Sheet Molding Compound method. A machine automatically positions several layers of carbon fiber composite in the basic shape, and under heat, this blank is pressed into the exact shape of the rear shelf. No further steps are needed. Mercedes-Benz is the first automaker to use components made by the Advanced SMC method.

McLaren Composites

The McLaren Composites company also manufactures more than 50 carbon fiber and fiberglass parts for the new high-performance sports GT car. The entire floor assembly, including all support members and securing points, is made in one piece, as is the roof frame, which is filled with foam before the resin is injected to create an especially crashworthy sandwich structure. High-strength bonding and riveting techniques connect the sections of the chassis and body shell. An aluminum sub-frame for the engine mounts is bolted to a carbon fiber bulkhead and bonded in place as well. In the rear, steel mounts are bonded into the carbon fiber for the rear differential/final drive unit.

PASSIVE SAFETY

A cutting edge restraint system with six airbags, seat belt tensioners and belt force limiters completes the safety picture on the SLR. In a frontal collision, the system first triggers the seat belt tensioners, which pull taut up to six inches of loose belt, limiting occupants’ forward motion. The belt tensioners are also activated if the car senses a rollover.

Smart Front Airbags Feature Two-Stage Deployment

In a more severe collision, two-stage front airbags also deploy. Two sophisticated sensors just behind the front bumper (on the radiator cross member) and one right in the passenger compartment (on the transmission tunnel) measure the severity of the impact, and an electronic control unit decides with lightning speed whether one or both chambers of the two-stage gas generators are triggered. In a high-force collision, both stages are deployed, inflating the front airbags more quickly. The driver’s airbag has a volume of 2.26 cubic feet when inflated, while the passenger’s front air bag is 4.41 cubic feet. The passenger air bag is larger because of a wider possible range of occupant positions.

Knee Bags Help Out

At the same time as the front air bags, two knee bags deploy from the underside of the SLR dash, supplementing the protection provided by the seat belts and front airbags as well as reducing the natural tendency for occupants to “submarine� under the seatbelts.

Belt Force Limiters Fine-Tune the Protection

An instant after the belt tensioners have tightened the seat belts and the airbags have deployed, belt force limiters allow the belts to loosen slightly, to take full advantage of the fully inflated airbags’ cushioning effect and minimize the risk of chest or shoulder injuries from the belts.

Side Airbags for the Head, Neck and More

In a side impact, an airbag deploys from the door, ripping open a seam above the armrest and inflating in milliseconds. Sometimes referred to as a “head-thorax bag,� the SLR door-mounted side airbag is oblong when deployed so that it covers most of the side window. This design provides crucially important protection to the head and neck, not to mention shielding occupants from glass shards and other intruding objects in a collision.

Complete with Baby Smart

The passenger’s front airbag can be turned off by the standard-equipment BabySmart system if it senses the presence of a BabySmart-compatible child seat. Available in several sizes, BabySmart seats feature a built-in transponder that communicates with sensors in the seat upholstery. Without anyone having to operate a switch or connect any wires, the system automatically deactivates the large front airbag on the passenger side whenever the BabySmart seat is installed in the car. However, the seat belt tensioner and sidebag remain active, providing valuable protection to a young passenger in an accident.

SLR DESIGN

From first glance, the Mercedes-Benz SLR McLaren speaks the dramatic design language of today’s Formula One race cars blended with an echo of classic styling elements. The bold look of the Silver Arrow race cars that took the Mercedes McLaren team to Formula One World Championship glory is apparent in the stunning road car, and when the gullwing doors of the new SLR swing open, its historic connection to the 1955 Uhlenhaut coupe becomes even more obvious.

Gullwing Doors with an Avant-Garde Look

In their modern interpretation, the SLR’s gullwing doors swing up and forward from the front roof post – the “A� pillar – instead of directly from the roof as with the Mercedes-Benz gullwings of the 1950s. The new doors open at a 107-degree angle, providing a safer, larger door opening (for easier access to the interior) and creating an exciting, futuristic look.

Powerful Proportions Connect the Future and Past

The overall look of the new SLR features powerful proportions that start from a long, broad front hood, transition into a compact passenger cell and finish with a short trunk section. The centerpiece of the front hood is an arrow-shaped nose that’s reminiscent of the Mercedes McLaren Formula One race cars that won World Championships in 1998 and 1999.

An F1 Nose with a Twin-Fin Spoiler

Another distinctive F1 element can be found under the arrow-shaped nose – a twin-fin front spoiler that’s more than decoration. The fins create aerodynamic downforce that contributes to the car’s sure-footed, race-car-like handling. The fin motif is a recurring theme that helps create design consistency across the exterior of the SLR. Finned sections connect the headlights to the nose, support the side mirrors and adorn the wrap-around taillights, where 51 LEDs on each side are housed in two fins, one above the other. The LEDs are brighter, last much longer and light up faster – about 150 milliseconds before conventional bulbs.

A Familiar Face Gets A Fresh Look

Above a large intake for engine cooling air, four elliptical headlights are arranged in a fresh treatment of the familiar face that has identified Mercedes-Benz cars for nearly a decade. On each side, two ovals form single units that house powerful xenon projection lights under clear covers that resemble high-quality camera lenses. The headlights form a strong starting point for the lines of the hood and front fenders. The contours of the lights develop into sculpted curves along the hood that deliberately evoke images of an athlete’s sinewy muscles. These taut lines sweep back to the A-pillars, visually connecting the nose of the car to the passenger compartment.

A Strong Profile, Too

From the side, the eye is caught by the SLR’s flat, wedge-shaped profile. This shape is created by the long front hood, a steeply raked front windshield and short trunk section, which together emphasize the sense of forward tension throughout the new SLR supercar. Just behind the front wheels, finned “gills� do much more than recall the design of Mercedes-Benz sports cars and racers from the 1950s. These stylized openings serve as vents for the all-important cooling air that exits the engine compartment, and under the gills, side pipes from the engine exit as well. The lines of the gills are accented by tapered fins that sweep back into the surface of the gullwing doors.

The SLR Interior Rocks

Inside the car, an obvious focal point is the center console, which is a visual extension of Formula One domes on the front hood. The console also picks up the lines of the front end as they flow over the transmission tunnel toward the back of the car. The upper console is dominated by the two knobs for transmission shifting modes, and a no-nonsense hand brake is nestled between the console and the passenger seat.

A Cocoon of Aluminum, Leather and Carbon Fiber

An interplay of materials creates a tasteful ambiance. Aluminum and carbon fiber contrast with supple leather that’s available in four color choices: Black, Orion Grey, Berry Red and the classic 300SL Red – the one color that uses extra soft “Silver Arrow� leather. The seats feature four different sizes of removable side bolsters that allow the one-piece buckets to be tailor-fitted. A 15-inch three-spoke steering wheel comes with rocker switches to operate the multi-function display as well as push buttons for manual gear shifting. Looking through the wheel, cleanly styled chronometer gauges are positioned squarely in front of the driver. An 8000-rpm tachometer shares center stage with a 220-mph speedometer, and they’re flanked by the requisite engine temperature and fuel gauges.

And A High-Performance Trunk

The trunk of this high-performance sports GT car is surprisingly roomy, with 9.6 cubic feet of luggage space finished in leather and velour. Lift-up flaps provide easy access to compart-ments for the two batteries, windshield washer and brake fluid reservoirs, and the tool kit. This layout helps ensure even front-rear weight distribution and a low center of gravity.

IN CONCLUSION

Combining unmatched supercar performance with surprising luxury and comfort, the SLR is destined to be a formidable competitor with revered brands from the other side of the Alps as well as the other side of Stuttgart. Unlike most of its direct competition, the SLR is equally at home on the way to the corner store, in city traffic, on twisty back roads and blazing down a race track at over 200 miles per hour. As a result, the Mercedes-Benz SLR McLaren is changing the way people think about supercars. And, never before has there been such collaboration among a World Champion Formula One race team, a renowned boutique for high-performance cars and a global luxury car brand. McLaren, AMG and Mercedes-Benz are on their way to reshaping the world of exotic and super sports GT cars.