Mercedes-Benz E320 BLUETEC

Mercedes-Benz E320 BLUETEC

by Mercedes-Benz PR

The Mercedes-Benz E320 BLUETEC

Heralded as the world’s most advanced diesel technology, BLUETEC combines several technologies to reduce exhaust emissions. BLUETEC is built on a foundation of advanced engine design that includes four valves per cylinder, centrally located piezo-electric injectors, the latest CDI direct injection, a turbocharger with variable nozzle turbine and exhaust gas recirculation.

Outside, the new Mercedes-Benz E320 BLUETEC looks just like other E-Class sedans. In fact, only the BLUETEC badge on the trunk lid identifies the new model. Inside, an additional warning light indicates glow plug operation. However, under the hood, its high-tech powerplant represents a dramatic step forward that seems destined to change people’s dated perceptions about diesels.

Farther, Faster, Cleaner

Like any diesel, the E320 BLUETEC will get improved fuel mileage and have increased cruising range less frequent trips to the filling station! than a gasoline-powered car, but more important, it does it without the usual tradeoffs of diesel ownership.

Starting the E320 BLUETEC on a cold morning, you can hear a muted version of the characteristic diesel engine sound. However, as soon as the car warms up, most people would be hard pressed to hear any difference between this car and a gas-powered model. Under acceleration, the E320 BLUETEC feels faster than the gasoline-engine E320, a result of its whopping 400 foot-pounds of engine torque – the pulling power of a V8!

The E320 BLUETEC Engine

Four-Valve V6 with Central Injectors

A new-generation 3.0-liter V6 diesel engine makes its U.S. debut in the E320 BLUETEC. The new 72-degree V6 diesel features four valves per cylinder, dual overhead camshafts and centrally located piezo-electric fuel injectors. Designed to spray diesel fuel directly into the center of the combustion chamber, each injector is positioned in the aluminum cylinder head about where a spark plug might be found on a four-valve gasoline engine. This layout ensures even dispersion of fuel as its flame front spreads concentrically across the combustion chamber.

Based on an aluminum block with cast-in steel cylinders, the BLUETEC V6 engine has an 83 millimeter bore and 92 mm stroke, a ratio that automotive engineers refer to as “under-square.” While most Mercedes-Benz gasoline engines are over-square bore is larger than the stroke!, many diesels have a relatively long stroke, in part to produce the high compression needed to make intake air hot enough for ignition.

To neutralize vibration that’s inherent to V6 engines, a balance shaft located in the block between the cylinder banks counter-rotates at the same speed as the crankshaft. The intake and exhaust valves are operated by twin overhead camshafts in each cylinder bank, with the intake cams driven by a double chain that also drives the balance shaft. A gear on each intake cam, in turn, drives the exhaust camshafts.

VNT Turbocharging

Although many non-turbo diesel engines have compression ratios higher than 20:1, Mercedes engineers found that, in conjunction with the BLUETEC engine’s exhaust-driven turbocharger, the engine is most efficient with a compression ratio of 16.5:1. The turbocharger features variable turbine geometry called VNT Variable Nozzle Turbine!, which is integrated with the electronic engine management system. To vary the combustion air volume quickly, VNT adjusts the guide vanes electrically as load and engine speed conditions change.

Air-to-Air Intercooler

To keep the turbocharged air as dense as possible on its way to the engine, the air flow passes through an air-to-air intercooler – essentially a radiator that cools the intake air. The intercooler system lowers the air temperature by up to 180 F. degrees, ensuring higher air volume and more power.

Electronic Throttle

Diesel engines usually operate without any throttle in the intake system, so that fuel delivery alone controls engine load and speed. However, Mercedes engineers found that, at light load, throttling one of the two diesel intake ports on each cylinder creates air turbulence that helps optimize the combustion process and further reduce fuel consumption and exhaust emissions. As a result, the BLUETEC engine makes use of electronic intake port deactivation that’s automatically managed by a sophisticate electronic control unit – the same one that determines everything from fuel injection quantity and timing to the vane angle of the VNT turbocharger and the quick-start glow-plug operation. This versatile microprocessor also networks with the seven-speed automatic transmission and the ESP stability control systems.

Common-Rail Direct Injection

The E320 BLUETEC uses the latest version of the Mercedes-Benz CDI system, which keeps fuel injectors supplied with approximately 23,220 pounds per square inch of fuel pressure through the common-rail fuel loop. An engine-driven fuel pump ensures consistent fuel pressure for the common rail, and the amount of fuel used by the engine is determined solely by how long the electronic injectors stay open.

Among other benefits, high fuel pressure is always available the instant the injector valve opens, and for as long as it stays open. Gone are the days of dealing with a mechanical injection pump’s gradual fuel pressure build-up for each cylinder, not to mention its pressure drop-off during each cycle – both representing distinct disadvantages, especially at higher engine speeds.

In spite of the high fuel pressure it generates, the engine-driven fuel pump requires less than 20 percent of the peak torque needed to turn a mechanical fuel injection pump. While mechanical injection pumps have to build up pressure for each injector pulse, the CDI pump maintains constant pressure and isn’t subject to the shock of such torque spikes. As a result, the pump imposes less stress and potentially less wear on the pump drive.

Piezo Injectors Use Magic Crystals

Electronic injectors of any sort were considered technically impossible for diesels until the mid-1990s, since they must remain reliable while they’re subjected to approximately 23,000 psi of fuel pressure. Used for the first time in a Mercedes-Benz diesel, the V6 diesel comes with piezo injectors that work faster and more precisely than the previous magnetic solenoid valves, making possible up to five injections with each piston stroke.

The new injectors use a piezo-ceramic element whose crystalline structure changes shape within 0.1 milliseconds when electric current is applied. As a result, piezo injectors are lighter and twice as fast as conventional electronic solenoid valves.

Miraculous Pilot Injection

Historically, the diesel combustion process has involved faster pressure increases and, as a result, more noise than a gasoline engine. Taking advantage of the speed and precision of electronic injection, Mercedes engineers found that igniting a small quantity of fuel a few times in rapid succession just milliseconds before the main injection pre-heats the combustion chamber and makes pressure and temperature increases more gradual. Smoothing out combustion pressure and temperature spikes softens the usual diesel noise and reduces oxides of nitrogen formation as well. Pilot injection simply isn’t practical with the relatively slow reaction times of mechanical injection, and the miracle of pilot injection is only possible because of the speed and flexibility of electronic fuel injection. Now with lightening-fast piezo injectors, five injections per stroke can be used instead of the previous three.

BLUETEC Exhaust Emissions

In large part because they usually operate unthrottled with lots of excess air, diesel engines inherently produce less carbon monoxide and carbon dioxide than a gasoline engine. However, because of their high combustion pressure and temperatures, diesels usually make more nitrogen oxides, which contribute to photo-chemical smog.

Diesel hydrocarbon emissions, primarily in the form of soot, are kept extremely low by the upstream benefits of the engine’s centrally located injectors – smooth, even and complete combustion – and two after-treatment devices in the exhaust system. An oxidation catalyst promotes downstream after-burning of any leftover hydrocarbons, while a particulate filter traps soot, even microscopic particles, and is automatically cleaned periodically via what approximates an oven-cleaning cycle.

NOx Storage Catalyst

In addition to using pilot injection and exhaust gas recirculation to minimize oxides of nitrogen, they’re further reduced in the E320 BLUETEC engine by a third device in the exhaust stream – an advanced-technology NOx storage catalyst that temporarily stores oxides of nitrogen. Regeneration pulses release a form of nitrogen oxide that reacts with exhaust gas to become harmless nitrogen.

In the Future – AdBlue Injection

If necessary, a BLUETEC system could be equipped with one more module – AdBlue injection. A water-based urea solution, AdBlue is carried in its own small tank and metered into the exhaust in minute quantities, so small that the tank only needs to be refilled during routine scheduled maintenance.

When AdBlue is injected into pre-cleaned exhaust gas, ammonia NH3! is released, converting nitrogen oxides into harmless nitrogen and water! in a downstream catalytic converter. Called SCR, for selective catalytic reduction, this process creates the most effective method of exhaust gas after-treatment currently available. In Europe, AdBlue injection has already proven effective in more than 10,000 Mercedes-Benz commercial vehicles, and the AdBlue supply network covers some 1,500 locations.

AdBlue has the potential to make the BLUETEC diesel as clean as a state-of-the-art gasoline engine. Mercedes-Benz USA is currently discussing AdBlue maintenance scenarios with the U.S. Environmental Protection Agency and the California Air Resources Board, with the goal of offering BLUETEC vehicles in all 50 states.

Seven-speed Adaptive Automatic Transmission

The E320 BLUETEC comes standard with Mercedes’ seven-speed adaptive automatic transmission featuring Touch Shift, which allows the driver to manually select all forward speeds by pushing the gear lever slightly left to downshift or right to upshift while in the “Drive” selector position. It’s not necessary to move the lever to another gate to make manual gear changes. An in-dash gear indicator shows the selected gear.

Though all forward speeds of the transmission can be selected, computer control prevents downshifts that would cause the engine to over-rev. Once the driver has used Touch Shift to manually select a gear, holding the lever to the right returns it to fully automatic Drive mode. The in-dash gear indicator will then display “D.”

The Mercedes seven-speed automatic simultaneously improves fuel economy and acceleration as well as making smooth, barely noticeable gearshifts. Seven gear ratios provide a wider spread of ratios between first gear and top gear and, at the same time, allow the engine to run in its most favorable rev range more often. It also gives the electronic control unit more flexibility in terms of maximizing fuel economy and making the transmission’s reaction time extremely fast.

Unlike most transmissions, the seven-speed will skip up to four gears if necessary when the driver downshifts, shifting directly from seventh to fifth, for example, or even sixth to second. This helps the transmission choose the perfect gear ratio for quick acceleration and ensure smooth, almost imperceptible shifts in the process.

Adaptive Electronics

When not shifting manually, the Mercedes seven-speed automatic not only adapts to changes in road grade delaying upshifts on ascents for climbing power and hastening downshifts on descents for engine braking!, but also to an individual’s driving style. The transmission computer adjusts shifting logic for leisurely driving with smooth upshifts at low engine speed for the best fuel efficiency. By comparing road speed changes and load throttle opening!, the transmission computer can discern uphill and downhill grades and adjust shifting as a result. It avoids annoying shifts back and forth between two gears on a long incline, and delays upshifts on descents for engine braking!, as a driver is likely to do with a manual transmission. A driver who does frequent highway merging will find the transmission holds each gear longer for quicker acceleration.

Lockup Torque Converter

The automatic transmission’s torque converter uses a lock-up clutch for maximum fuel efficiency. After starting out, the lock-up clutch engages in all gears, not just in top gear like many other transmissions. Slight computer-controlled slippage is allowed to prevent drivetrain vibration. Designed to last the life of the car, the lock-up clutch is submerged in transmission oil and uses special long-life friction materials.

Chassis

Like other E-Class models, the E320 BLUETEC makes use of S-Class suspension design and technology. In front, a four-link design employs spring links, torque struts, upper wishbones and the steering track rods. Conceptually, this front suspension is similar to a double-wishbone layout, but with a two-piece lower wishbone. The Mercedes-patented five-link rear suspension design is adapted in aluminum on the E-Class.

Rack and Pinion Steering

All E-Class models are equipped with power-assisted rack-and-pinion steering. In the current generation, response has been quickened and now delivers 2.8 turns lock-to-lock, compared to 3.3 in the previous model.

The speed-sensitive system boosts steering assist at low speeds for easier low-speed maneuvering and parking and reduces it at higher speeds for improved steering precision and feedback.

Braking Power

The E320 BLUETEC comes with 8 x 16-inch aluminum alloy wheels shod with 225/55R16 all-season tires, employing vented disc brakes in front and solid discs at the rear with single-piston floating calipers at all four corners. Mercedes-Benz was the first automaker to make standard an electronic brake-assist system that can recognize emergency braking and automatically apply full-power brake force for shorter stopping distances. Called Brake Assist, the system is activated only in emergency braking situations and doesn’t affect normal brake operation. Testing shows that Brake Assist can provide shorter stopping distances, even for skilled drivers.

Brake Assist is a driver-adaptive system that learns each driver’s braking habits by using electronic sensors to monitor brake pedal movement and feed information to a mini-computer. As a result, when the system recognizes pedal speed signals that clearly mean an emergency, the computer instantly applies an electronic valve on the brake booster system for full braking. Brake Assist takes advantage of the standard ABS, which prevents the wheels from locking up under braking. As soon as the driver eases up on the brake pedal, normal brake control resumes.

To exchange important data at lightening speeds, the Brake Assist networks with other in-car micro-computers for ABS brakes, ASR traction control or ESP stability control, and the engine/transmission electronics. The system even processes information about the amount of brake wear and vehicle speed.

ESP Electronic Stability Control

Mercedes-Benz was first to introduce a true automatic stability system in 1996 with the Electronic Stability Program ESP! in the S-Class. All Mercedes-Benz passenger vehicles now come equipped with ESP. The system enhances driver control and helps maintain directional stability in turns as well as when driving straight ahead, including over uneven surfaces and over patchy snow, ice or gravel. The straight-line traction control function is integrated into ESP.

Mercedes ESP uses a steering angle sensor, speed sensors at each wheel, sensors for lateral acceleration or lateral g-force! and vehicle yaw the vehicle’s rotation on a vertical axis!, and computer logic specific to the model to calculate the path being steered. Simultaneously, it calculates the car’s actual path.

If there’s a discernable difference between what the driver asks through steering! and the vehicle’s path, ESP applies selective braking braking one wheel, front or rear, left or right! to put the car back onto the driver’s intended path. ESP measures a tendency toward understeer when the front resists steering changes, causing it to “plow”! or oversteer when the rear end “fishtails”!. When it senses understeer, ESP increases brake pressure to the inside rear wheel. In an oversteering condition, ESP increases braking to the outside front wheel. ESP is effective during acceleration, braking and coasting.

Body

Lightweight Materials

The E-Class features the first-ever use of aluminum in large-scale series production by Mercedes-Benz. Following the principle of “the right material in the right place,” Mercedes engineers use aluminum only for those areas where it holds the greatest benefits compared to steel, and these components include:

· Hood

· Front fenders

· Trunk lid

· Front subframe and cross member

· Rear subframe

· Rear parcel shelf

· Rear wall behind the rear seat backrest on models without split folding rear seat!

All other components in the body shell are made from sheet steel, with the proportion of high-strength steel grades increased from approximately 20 percent in the previous E-Class to about 37 percent in the current model. Various underfloor components as well as the reinforcements used around the bumpers and springs are made from a special grade of high-strength steel with an unusual dual-phase microstructure that helps it withstand extremely high loads. The spare tire well is made from plastic. The body shell materials as a percentage of weight are:

o Steel – 52%

o High-strength steel – 37%

o Aluminum – 10%

o Plastics – 1%

Many of the body shell panels are machined using the “low-stress joining” principle to ensure precision fitting. The flanges around the borders of the steel parts are shaped so that any tolerances are balanced out as soon as the panels are placed together, allowing the bodywork components to be welded to one another under low-stress conditions. The rear side members, the new firewall cross member, the rear wall of the passenger cell and the parcel shelf all employ this sophisticated manufacturing process.

Corrosion Protection

Precision fitting of the bodywork components, low-stress joining technology and state-of-the-art spot and laser welding methods used for assembly of the body shell all combine to further enhance corrosion prevention. These assembly techniques nearly eliminate the need for extra soldering joints and MAG metal active gas! welding seams at the panel joints, which used to be particularly susceptible to rusting.

By lining the entire underbody of the vehicle with a total of 11 plastic panels – which also enhance aerodynamic performance – Mercedes engineers were able to omit the conventional PVC underbody protection in the new E-Class without compromising long-term corrosion prevention. These panels cover the engine compartment, wheel arches, outer floor panels and rear axle links, effectively protecting the body from stone chips that could lead to rust.

Safety

A Giant Step for Accident Avoidance

The 2007 E-Class features PRE-SAFE®, a revolutionary system that made its industry debut in 2002 on the S-Class. Mercedes-Benz safety engineers felt that cars could be equipped to take preventive action in the valuable seconds before the actual impact when sensing an imminent crash. As a result, they designed the innovative PRE-SAFE system to first tension the seatbelts if the car senses an impending collision. The system uses electric tensioners in addition to the existing pyrotechnic belt tensioners that deploy in some crash scenarios. If a crash is averted, the electric belt tensioners unwind and are ready to deploy again.

What’s more, if the front passenger seat is overly reclined or forward, and if the seat cushion angle is too shallow, PRE-SAFE moves it to a more favorable crash position. Finally, if the vehicle skids sometimes a precursor to rollover!, the system automatically closes the sunroof.

PRE-SAFE reacts to fishtailing or oversteer! as well as “plowing” or understeer! by using existing sensors for ESP stability control to measure steering angle, vehicle yaw and lateral acceleration. Emergency braking can also trigger PRE-SAFE, which monitors sensors for the Brake Assist system as well.

Intelligent Restraint Systems

The adaptive restraint systems in the E-Class optimize deployment of the seatbelt systems and the supplemental restraint system SRS! airbags, depending on the type and severity of an impact. The E-Class sedans are equipped with eight airbags – two in front, one side bag for each outboard passenger and a side curtain windowbag for each side.

All five seating positions in the E-Class are fitted with three-point inertia-reel seat belts, with all outboard positions also including electronically controlled belt tensioners. In a collision, the tensioners take up the seat belt slack at lightning speed, thereby anchoring the passengers to the seats. Thus, the occupants “take part” in the deceleration of the vehicle earlier and forces are reduced. A few milliseconds later, a belt force limiter for the driver and all outboard passenger seats limits the restraining action of the belt, helping to reduce the risk of chest and shoulder injuries.

Supplementary crash sensors provide early detection of the type of collision, and new control algorithms mean deployment of the airbags and belt tensioners can be adapted even more closely to suit actual requirements. These measures help to reduce the loads exerted on occupants in the event of serious collisions and at the same time optimize the protective functions employed in moderate-speed collisions.

Locating two crash sensors on the radiator cross member allows them to detect collision severity even sooner and with greater precision than the primary crash sensor on the transmission tunnel is able to do. The electronic control module uses information from the front-mounted sensors to:

o ... further reduce the amount of time that lapses between the impact and the point at which the belt tensioners are triggered.

o ... control the front seat belt force limiters adaptively, according to the particular type of collision.

o ... trigger the driver’s and front-passenger airbags not just earlier but in two stages, depending on the type of collision see below!.

Two-Stage Front Airbags

The front airbags for the driver and front passenger deploy in two stages, depending on the impact severity. If sensors detect a minor front-end impact, only one chamber of the gas generator is deployed, so the bag is not filled as fully or as quickly as it is in a severe front impact. In a more severe collision, the second chamber is deployed 5 to 15 milliseconds later.

Accident research indicates that this adaptive airbag control is especially beneficial in medium-force collisions, as the first airbag deployment stage allows occupants to be cushioned more softly.

The E-Class incorporates a system that accounts for the body weight of the front-seat passenger when deploying the front-passenger airbag. A special electronic measuring pad in the seat upholstery automatically assigns the front-seat passenger to one of four weight categories: less than 67 lb, 68-111 lb., 112-154 lb. and 155 lb. and over. The airbag can then, for example, trigger both stages even in low-impact collisions to provide heavier front passengers an optimal level of protection. The second airbag stage will only be deployed for lighter passengers, on the other hand, once a higher severity threshold is reached. The measuring pad also monitors seat occupancy, automatically deactivating the airbag, belt tensioner and side bag on the front passenger side when the front passenger seat is unoccupied. The adaptive system therefore helps to reduce repair costs.

The front sidebags in the E-Class are housed in the seat backrests, while the rear sidebags are located in the door trim. In the event of a side impact, the sidebags inflate in a split second to cover the area between the occupant and the door up to chest height, helping to reduce the forces acting on the upper body and lateral whiplash movements of the head. The sidebags all have an inflated volume of ten liters.

Where side airbags protect against chest injury, the side curtain airbags protect the head and neck, resulting in one system complementing the other. The windowbags meanwhile are positioned behind the trim panels for the roof frame and the A and C-pillars. The air cushions on either side inflate within just 25 milliseconds and remain fully inflated for several seconds following the collision.

Active front head restraints

New for 2007, active front head restraints move forward more than 1¾ inches 44 mm! and upward by more than an inch 30 mm! in the event of a rear collision that exceeds the system’s deployment threshold, helping to support the head and reduce the likelihood of whiplash injuries

Rollover Protection

The E-Class is equipped with a sensor that can signal the central control module to deploy the windowbags and belt tensioners if it detects an impending rollover. The sensor is positioned on the transmission tunnel. Inside its casing is a metal rod that responds to electrical input and vibrates like a tuning fork.

The Coriolis force force of inertia in a rotating system! that acts when the vehicle rolls over alters the frequency of the “tuning fork.” The microcomputer senses this change and instantaneously activates the protective systems. The E-Class accommodates child seats with the standardized LATCH system Lower Anchors and Tethers for Children!.

The Safety Cell

High-strength components – which include some made from a state-of-the-art, dual-phase steel renowned for its high load resistance – combine low material thickness with maximum strength. The E-Class absorbs impacts in three phases. In impacts up to 2.5 mph, the flexible bumper covers deform but then return to their original shape. The aluminum cross member behind the bumper redirects the forces to the side not subject to any direct load, thereby playing a definitive role in the absorption of the impact energy. Special replaceable “crash boxes” aluminum in the front and steel in the rear! absorb crash energy at impact speeds of up to 9.3 mph 15 km/h!, ensuring that the supporting structures behind remain undamaged.

Bolted connections make the front and rear crash boxes easier to replace after a low-speed impact, eliminating the need for straightening, welding and repainting. Even the individual components contained within the modules are bolted together.

At higher impact speeds, the reinforced rear side members of the body shell use a continuous closed box section with carefully graduated material thickness to absorb high forces. A plastic fuel tank is located under the back seat where it is protected from most impacts.

Front Safety Structure

The E-Class uses a front safety structure with a continuous cross member that connects the two firewalls. Replacing the forked-member concept used in the previous model, this design helps protect the passenger cell by distributing the force of a frontal offset impact over a broad area, even into the transmission tunnel and the side members. A new type of vertical reinforcement further increases the strength of the firewall and restricts movement of the pedals toward the passenger compartment in a frontal collision.

Single-Piece Sidewalls

Although the sidewalls of the E-Class form a single section, they are made up of a number of tailored panel blanks that are laser-welded together and then pressed into the desired shape. A steel tube inside each B-pillar also helps to reinforce the passenger cell in the event of a rollover. High-strength steel blanks are used for the inner door shells, and each door incorporates a side-impact beam made from high-strength cold-formed steel.

High-strength door hinge mounting plates are welded to the inner door shells. The result is a rigid integrated side structure that provides effective protection in the event of a side impact.

High-Strength Manufacturing

Mercedes employs several different manufacturing processes to add strength to the body structure without adding excess weight. The main floor assembly consists of three different tailored blanks, which are laser-welded together and then precision fitted. The middle of the three blanks is a thick 1.0 millimeter! panel forming the transmission tunnel, the sturdy backbone of the passenger cell.

A “flexible rolling” technique is used for making the two connecting members, which extends the front side members back into the structure of the floor assembly, giving them the required material thickness and strength. This is the first time the flexible rolling technique has been used in large-scale series production. In this process, high-strength steel can be machined at the rolling plant in such a way that a single component can contain varying panel thickness.

As an example, the front of the connecting members, where the loads are greatest in a collision, is made thicker 1.15 millimeters! than the rear section 0.88 millimeters!, which is not subject to such high loads. Impact energy flows more smoothly through a component made with this process compared to using a number of different, pre-fabricated panel blanks joined together.

In addition to the two flexibly rolled connecting members, the body structure features a solid cross member running under the front seats, a load-bearing section between the B-pillars and reinforcement paneling in the footwells. The rear side members use a continuous closed-box section with carefully graduated material thickness, which enables them to absorb high impact forces in a rear-end collision.

The Mercedes-Benz E320 BLUETEC is available with an optional split-folding rear seat, which required a new wraparound structural support for the rear wall of the passenger cell. This structure is welded together with the sidewalls, the floor paneling and the parcel shelf, forming a solid foundation for anchoring the backrest hinges and locks. The structure also contributes to the body shell’s high torsional rigidity.

The Tele Aid Connected Car with Emergency Response

In the E-Class, passenger safety does not end with protection in the collision. The E-Class comes standard with the Mercedes-Benz Tele Aid system, which can summon emergency response in the case of a severe collision. Tele Aid is activated immediately when any of the belt tensioners or airbags deploys, generating a direct call to an emergency response center over a dedicated, crash-secure cellular line and redundant antennas. Occupants can also activate Tele Aid by pushing a button marked “SOS” in the ceiling near the rear-view mirror. GPS satellite location provides the response specialist at the other end with vehicle location. If emergency response is needed, it can be summoned immediately, with exact vehicle location, plus full information on the car model and color for quick recognition by emergency services.

By pushing another button identified with a wrench symbol, Tele Aid can also connect the car to Mercedes-Benz Roadside Assistance, which among other things, can allow occupants to talk directly to a technician at a nearby dealership. A third button marked with the letter “i” will connect occupants to the Mercedes-Benz Customer Assistance center, whose staff can help if there are questions about operation of the car or any non-emergency concerns.

Design

Unmistakably Mercedes

The latest E-Class carries forward the unmistakable identity of its predecessors while advancing design themes introduced with the most recent Mercedes-Benz models. The basic body packaging of the E-Class is already highly efficient, comfortable and roomy.

The previous E-Class ushered in the four-headlamp face theme that has evolved into steeply slanted elliptical headlight units on the latest model. Together with a variation on the classic Mercedes grille, the “eyes” of the E-Class determine the shape and lines of the entire front section. The hood and fenders take the striking curves of the headlamps and stretch them back toward the rear in taught, powerful bulges.

New Look for the 2007 Line

With a more aggressive front bumper and lower air dam as well as a restyled front grill and headlights, the 2007 E-Class sports a fresh look, which includes more aerodynamic side mirrors as well as a redesigned rear bumper and tail lights. Inside, the E-Class reveals a new steering wheel and shift lever, a revised layout for the automatic climate control and four new interior colors. New standard equipment includes a glass sunroof, six-disc CD changer and harman/kardon Logic 7 ™ premium audio system. In addition, the wagon model now includes a power tailgate.

An arched roof and sweeping C-pillars give the sedan a coupe-like flavor, with black-painted B-pillars designed to blend unobtrusively into the door glass. Flared wheel arches highlight and reinforce the “lower” look. Yet, the car is nearly a half-inch higher than the previous one.

The rear section, with its compact proportions, emphasizes a coupe-inspired profile. Their rear light units extend into the rear quarter panels to draw a strong connection between the sides and rear of the car.

Slick Aerodynamics

The E-Class slips through the air with very low resistance, due to a 0.27 coefficient of drag compared to 0.29 for the previous sedan!. Subtle aerodynamic improvements that add up include underbody paneling, integrated wheel arch spoilers, a subtle spoiler molded into the edge of the trunk lid and close attention to the front wheel opening shape.

In most wind tunnels, the wheels of a car being tested remain static. Mercedes used a new type of wind tunnel to evaluate the E-Class where two conveyor belts drive the wheels, allowing engineers to study the influence of turning wheels on drag and lift forces. Their findings influenced the shape and structure of the underfloor paneling and the wheel spoilers.

Seeing In The Rain

Attention to aerodynamic efficiency also yields gains for wet-weather visibility. Aluminum channels in the A-pillars collect rain from the windshield and deflect it over the roof, where it flows into a drainage channel between the roof and the rear window weatherstrip. The exterior mirror housings likewise manage rainwater, routing it downward at a flat angle and into the oncoming air stream.

The driver’s side windshield wiper follows a fixed axis of rotation, while the passenger-side wiper follows an eccentric sweep that enables it to clear an even larger area. Instead of the jointed system used on conventional wiper blades, the Mercedes aero wipers consist of a single-piece rubber section with integrated spoiler and externally spring runners. The standard rain sensor located on the windshield regulates the windshield wipers depending on the intensity of the rain.

When the wipers are turned off, both wiper arms lie on a ledge on the passenger side that is heated via a special air duct in the dashboard. Wiper heating is activated whenever the heating or the air conditioning is set to defrost. The windshield washer’s two twin-jet water nozzles are electrically heated, as are the washer fluid reservoir and hoses.

High-Tech Lighting

Projector-type halogen headlamps behind polycarbonate lenses require less space than conventional lights, which gave the designers more latitude in the shaping of the front end. At the same time, these lights produce wider and more even illumination of the road ahead and provide a greater headlamp range of around 460 feet.

Optional active-curve illumination points the headlights into each curve, based on steering wheel angle and vehicle speed. The active-curve lights are packaged with bi-xenon high-intensity gas-discharge headlights HID! that use a mechanical shutter to switch the xenon bulb from low beam to high beam function. The bi-xenon headlights are quickly self-leveling, and are therefore always aimed properly, regardless of vehicle loading, even with the pitching of braking or acceleration. The package also includes a high-pressure jet wash system that cleans the lenses at the touch of a button.

Lights That See Around Corners

The optional bi-xenon lights also feature active-curve technology, in which the headlights actually turn slightly with the steering wheel to light up each approaching curve. Adapting its response to vehicle speed as well, this feature improves road illumination in turns by 90 percent, in comparison to fixed halogen lights! In addition, this package includes fog lights that double as cornering lights, which turn on below about 25 mph when the headlights are on and the turn signal is operated, or the steering wheel is turned. Each cornering light illuminates one side of the vehicle to an angle of about 65 degrees and a distance of up to 40 feet. These lights are designed to fade in and out, giving the human eye time to adjust!

Mercedes engineers put great emphasis on the role that lighting plays in overall safety. Several measures ensure proper lighting, including:

· Emergency lighting - In the event that a data line or electronic control module develops a defect, a pre-programmed circuit prevents the total failure of the vehicles lighting systems.

· Failsafe lighting - If a bulb that is important to the vehicle’s operating safety should fail, the electronic unit will switch on other bulbs that are able to temporarily fill in for the lost light source.

· Daytime driving lights

· Headlamp switch-off delay allows the driver to set “walk away” lighting for up to 60 seconds after leaving the vehicle.

· Locator lighting - When the E-Class is unlocked in dark conditions using the remote control, the parking lights, taillights, license plate lamp and front fog lamps will come on for up to 40 seconds to help the driver find the car more easily. This function can again be programmed from the multifunction steering wheel and the main instrument cluster display.

Interior

Mercedes gave the current E-Class a more organic and elegant interior design, highlighted by sweeping curves and soft surfaces. The instrument panel adopts a “double-sweep” cockpit theme. Distinctive, strong lines are characterized by their seamless integration into the center console and door panel trim. The design combines with high-quality materials and delicate chrome trim to infuse the E-Class with greater elegance than before.

The flowing lines of the dashboard are complemented by the surface made from a soft-touch polyurethane skin sprayed onto the base material, providing a luxurious feel and high-quality appearance. This production technique enables a smoother integration of such elements as air outlets and eliminates unattractive panel seams. Even the passenger-side front airbag cover has an invisible seam. A horizontal burl walnut trim strip separates the upper section of the instrument panel, which remains in a darker shade, from the lower section, which shares the color of the interior. Discrete chrome trim is used throughout interior and underlines the sense of elegance.

Similar to the CLK coupe, an elegant touch for the door trim is a thin chrome accent strip integrated into the burl walnut. A wood/leather steering wheel is optional.

Cockpit Design for Both Form and Function

The cockpit-style instrument panel includes three circular gauges with chrome trim rings - a speedometer in the center, flanked on the right by a tachometer and on the left by the analog clock. New electronic vertical bar graphs for the fuel gauge and coolant temperature provide more accurate readings for these functions. Warning lights are positioned within the driver’s field of vision at logical locations, not just grouped together. For example, the low fuel warning light is next to the fuel gauge, the coolant warning light next to the temperature gauge.

Lamp units encircling the front and rear overhead control panels provide six driver-selectable levels of interior lighting. The nightlight at the rear can be dimmed using the two buttons in the overhead control panel.

A magnesium crossmember forms a strong anchor for the dashboard and its components. The audio system, automatic climate control, instrument cluster and steering column are all attached to this solid structure, which both minimizes vibrations and contributes to low noise levels inside the E-Class.

The dashboard itself has a soundproof design and is completely insulated at the front, preventing engine compartment noise from entering the passenger compartment. Even the cable and wire openings between the interior and the engine compartment have airtight seals to eliminate so-called sound bridges.

The sweeping console groups many of the car’s controls for easy reach, including audio system and climate control, remote fold-down rear headrests, the motion sensor disabling switch as well as optional heated seats, power rear sun shade and Parktronic parking assist.

Multifunction Display

The multifunction display in the center of the speedometer is linked to the illuminated buttons on the steering wheel, allowing the driver to view the selected radio station, a personal phone book or even navigation instructions when the optional GPS navigation is ordered. Characters and symbols are displayed in easy-to-read white against a blue background.

The sweeping console groups many of the car’s controls for easy reach, including audio system and climate control, remote fold-down rear headrests, door locking-unlocking, optional heated seats, power rear sun shade and Parktronic parking assist.

The center console features a flip-up panel that’s powered by mini electric motors. At the touch of a button, the panel of switches moves smoothly upwards, allowing occupants to access the 6-disc CD changer optional! or storage compartment located behind it. About 30 seconds after it is opened, or after a button was last pressed on the CD changer, the panel automatically closes.

Depending on the equipment fitted, illuminated switches for the central locking, ESP®, hazard warning lights, seat heating, rear head restraints, rear-window roller blind and seat ventilation are located on this switch panel. The switches remain fully functional even when the switch panel is flipped up.

First-Class Seating

Standard 10-way adjustable power seats incorporate a suspension design for greater comfort. The seat frame consists of an aluminum suspension base supported by a hinge at the front for adjusting the angle, and by two small coil springs at the rear. This design enables the seat base to swing on the frame and, along with the foam cushions inside the aluminum shells, perform further suspension and shock-absorbing functions.

Traditional Mercedes-Benz seat controls are conveniently located on the door panel. Seat positions can then be stored in memory for up to three people!, which also stores steering wheel and exterior mirror placement. Three drivers using three different keys can program their own specific settings. The system provides an added convenience when exiting the car. When the SmartKey is removed, the steering wheel automatically moves upward and the seat moves rearward to provide more room for exiting. Both the seat and the steering wheel return to their original positions as the driver is seated and the SmartKey inserted.

Four-Zone Climate Control

The E320 BLUETEC comes standard with dual-zone automatic climate control that allows the driver and front passenger to set different temperature levels. The system has a multifunction sensor that monitors humidity and pollutant levels in the ambient air. Should nitrogen oxide and carbon monoxide levels in the air exceed a certain threshold, the climate control system automatically switches over to air recirculation mode.

Two Ways To Let The Sun In

Customers can choose between two roof options – a standard tilt/slide power glass sunroof and a Panorama sunroof with twice the glass surface area. The Panorama roof sports continuous glass from the windshield to the rear window. At the push of a button, the front section of the roof glides backwards, while a glass louver pops up to act as a wind deflector.

Because it slides along on top of the roof, the Panorama sunroof does not restrict occupant headroom. As with the tilting/sliding sunroof, the moving section of the roof can also be tilted upward. The SmartKey remote will operate either optional roof. The Panorama roof also features power-operated roller shades block out the sun’s rays.

Enhanced COMAND

The COMAND control and display system with optional GPS satellite navigation offers unparalleled function. The system includes a 6.5-inch color TFT display screen on the center console, CD player, plus a full array of mobile communications functions when combined with one of the optional hands-free communications system. The navigation computer uses its own integral DVD player to accommodate the map database disc.

Surround Sound On Wheels

A standard harman/kardon Logic7 digital surround-sound system provides an even more luxurious listening experience. The system converts every conventional stereo signal from the car radio and CD player into surround sound with seven output channels, offering sparkling audio for passengers, regardless of where they are sitting. The 420-Watt sound system includes a digital signal processor, plays through 12 high-end speakers and even compensates for ambient driving noise. Two speakers on the rear parcel shelf produce the surround effect.

The CD player can play both audio CDs and MP3s, while an “aux” plug in the glove box allows personal audio devices to be connected directly to the car’s audio system. An optional iPod integration kit connects jack-equipped Apple iPods to the audio system, providing program

Power Trunk Closer

The E320 BLUETEC can be equipped with an optional remote electronic trunk closer. Pressing a button on the driver’s door or the SmartKey remote control opens the trunk lid gently by means of an electric motor and two springs. Pressing a button on the inside of the lid, the remote control or on the driver’s door pulls the lid downward, and it then closes fully by virtue of its own weight pushing down on the lock. A servo locking mechanism then locks the lid completely. As a safety precaution, applying light force on the lid will stop it from closing.

Go With Keyless Go

With the optional Keyless Go system, Mercedes-Benz once again pushes the convenience envelope. Antennas located in several locations in the car pick up a signal transmitted from inside the SmartKey. As long as the driver has the key in a pocket or bag, simply touching one of the door handles or the trunk handle unlocks the car. After depressing the brake pedal, the driver starts the car by touching a button on top of the shift knob. Keyless Go also makes it impossible to lock the keys in the trunk. If the keys are dropped into the trunk and the lid closed, the lid will automatically pop open in a few seconds.

Park with Parktronic

The optional Parktronic system uses a series of sonar-type sensors in the front and rear bumpers to detect obstacles in front, behind and to the left and right of the car’s corners. The system displays the proximity of obstacles using bar graph light displays, one on the center dashboard for the front and another for the rear, visible in the rear-view mirror. The system also provides an audible warning.

What’s Up with Diesel Fuel?

Related to kerosene on the fossil-fuel family tree, diesel fuel is more like thin oil than gasoline. It requires less complex processing from crude oil and holds more potential heat energy than gasoline. Although it’s still not sold at every filling station, diesel fuel is becoming more widely available every year, and at about the same price as regular gasoline.

Cetane is to Diesel as Octane is to Gasoline

While gasoline is rated by octane the higher the number, the greater its resistance to dangerous detonation or uncontrolled compression-ignition!, diesel fuel is rated by its cetane, a measure of how readily it ignites in compressed air. In a sense, cetane is the opposite of octane, but in a diesel engine, higher cetane numbers mean faster and more complete combustion as well as lower exhaust emissions and less engine noise.

Diesel fuel sold in the U.S. is required to have a minimum cetane rating of 40, but studies have shown a wide variance at the pump, from around 42 to 52. By comparison, diesel fuel in Europe has cetane ratings between 51 and 55. The Mercedes-Ben E320 BLUETEC engine is designed to deal with this range in fuel cetane.

Getting Rid of Sulfur

Sulfur that occurs naturally in diesel fuel has hampered efforts to reduce diesel tailpipe emissions. In untreated form, diesel fuel can have as much as one percent or 10,000 parts per million ppm! of sulfur, which is enough to form corrosive sulfuric acid during combustion that can accumulate in the oil and damage fuel delivery, engine parts and exhaust after-treatment systems.

For years, the maximum allowable sulfur content in U.S. fuel was 350 ppm, but the October 2006 arrival of “clean” ultra-low-sulfur diesel fuel only 15 ppm!! in the U.S. helps make diesel engines even cleaner. Already in use across Europe, clean diesel is nearly devoid of sulfur, which further reduces diesel exhaust emissions and, for the first time, allows new barium-coated catalysts that will help reduce nitrogen oxides NOx!. Reducing sulfur in diesel fuel also lowers other undesirable compounds such as polycyclic aromatics.

Diesel is Oil, Too

Modern distributor injection pumps and CDI pumps are lubricated solely by the diesel fuel flowing through them. What’s more, the lubricating qualities of diesel fuel become increasingly important as fuel pressure climbs. If the lubricity level is too low, injection pumps are subjected to increased wear, which can lead to pump failure.

Diesel fuel lubricity is rated by the HFRR method – the lower the HFRR value, the higher its lubricity. Experts consider a value of 460 to be the highest acceptable number for normal pump wear, and fuel with higher numbers lower lubricity! can shorten pump life significantly. The E320 BLUETEC is equipped with a special lubricity package to overcome such fuel shortcomings.

Water Contamination

Improper bulk storage sometimes contaminates diesel fuel with water, which can result in serious corrosion within the fuel injection system. The Mercedes-Benz E320 BLUETEC has a water separator that removes water before the fuel is injected. When it’s full, the water separator should be emptied by authorized Mercedes-Benz dealer service department staff.

Keeping Injector Nozzles Clean

Diesel injector valves live in the heat and exhaust gas of the combustion chamber, and as a result, injector nozzles tend to accumulate carbon, which can narrow or even clog the fine metering holes in the end of the nozzle. Diesel fuel producers try to ensure that injector nozzles stay clean by using certain detergent additives in their fuel, but there’s no measurement for this parameter and no consistent standard.

SOME BACKGROUND ON DIESEL

The Big Benefits of Diesel

In general, diesel engines get 20-40 percent better fuel economy and thus also produce 20-40 percent less CO and CO2 than comparable gasoline engines. What’s more, a modern BLUETEC diesel is as powerful and nearly as quiet and clean as a gasoline engine. Recent showings of diesel-hybrid concept vehicles underscore the key role that advanced diesel technology will play in the future. The “car of tomorrow” is likely to integrate several technologies in a user-friendly, high-efficiency, low-emissions vehicle.

Mechanical Fuel Injection

Until Mercedes-Benz presented the world’s first diesel engine with electronic injection in 1997, virtually all diesels used mechanical fuel injection. The heart of every mechanical system was an engine-driven mechanical pump that itself resembled a miniature cylinder block. Tiny pistons the diameter of pencils pressurized diesel fuel for each cylinder, and complex mechanical controls regulated rudimentary fuel-air curves for various load, speed and temperature ranges. These elaborate mechanical controls grew even more complex as engineers addressed increasingly stringent exhaust emissions regulations. What’s more, mechanical systems were slow to react and not nearly as responsive as electronic systems. However, until recently it wasn’t considered technically possible to build an electronic injector that could deal with the mind-boggling high fuel pressure required to penetrate the highly compressed air of a diesel combustion chamber.

CDI Electronic Fuel Injection

In late 1997, Mercedes-Benz debuted the first diesel engine with electronic fuel injection. Called common-rail direct injection or CDI, the system instantly created a new paradigm for the diesel industry by providing much more precise control of injection quantity, simultaneously making more power, lower exhaust emissions and quieter operation.

Most electronic fuel injection systems, including those on gasoline engines, use a “common rail” or “ring main” fuel loop to supply the same pressurized fuel to all injector valves. However, the CDI system marked the first common-rail system for diesel engines, and the E320 CDI was the first electronically injected Mercedes-Benz diesel to be marketed in the U.S.