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MB Technical Expressions Explained

Major Update     Version 2.0  November 20th 2000      Major Update

 
Have you too been confused by the many new technical expressions for late MB`s? 
To clear up things a bit here is a page with some of the most important ones explained.
Any additions and corrections are always welcomed, drop a line (or two): jaguare@bigfoot.com



 
ABC
Active Body Control
Suspension system with hydraulic cylinders. ABC compensates the body movements at braking, starting and in corners (pitch and roll).
The body always stays in a horizontal position.
Was first available in 1999 in the S-Class coupe CL (C215)

ABS
Anti-lock braking system
Sensors on each wheel detect when a wheels blocks when the driver brakes and within milliseconds reduces the brake pressure for that wheel so it turns again. Then again maximum brake pressure is applied to the wheel, the wheel blocks and the abs-sensors cause the brake system to reduce the brake pressure on the wheel again.
ABS retains a cars manoeuvrability even when the driver fully steps on the brake pedal.
ABS was first used in mass production in Europe by Ford in the Scorpio (Granada in the UK) series.

Active Anti Noise
The electronics detects the frequency of the noise and over the car`s loudspeakers steer against exactly. The noise is "wiped out" and its quiet in the car.

ADS
Adaptive damping system
Explanation to be added later

Airmatic
Instead of a conventional suspension- and damping-system with gas pressure shock absorbers an air suspension with adaptive dampers are used. The body is supported by compressed air.

ASSYST
Active Service System
Engines are equipped with a microcomputer that monitors the aging of the motor oil via data transmitted by sensors and calculates an individualized maintenance plan for the engine: A digital indicator in the
cockpit notifies the driver of the number of kilometers remaining before the next maintenance check.

All engines fitted e.g. in the C-class (W203) sports coupé are equipped as standard with the Active Service System ASSYST, which registers the varying operating loads individually and takes these into account for scheduling engine maintenance. On the basis of sensor-derived data such as oil level, oil temperature, coolant temperature, engine speed, road speed and engine load, a micro-computer calculates the actual load on the engine oil and works out a servicing schedule for the engine which reflects this. The central display in the instrument cluster tells the driver how many kilometres can be covered and how many days or weeks remain before the next maintenance service is due. The Active Service System includes an oil level sensor which, as well as warning the driver when the oil level is too low or too high and indicating the amount in litres which needs to be added or drained off, also knows when the driver has topped up with fresh oil and extends the oil change interval accordingly.

Automatic child seat recognition
The front passenger seat e.g. of the Mercedes-Benz C-class (W203) sports coupé is equipped as standard with technology which automatically recognises special rearwards-facing child seats fitted with a transponder system. The electronic unit transmits a coded inquiry signal via two antennae in the seat upholstery, which receivers (transponders) in the base of the rearwards-facing child seat decode and then reply to with a response code. This code is relayed from the seat antennae to the airbag electronics which thus 'recognise' that such a child seat is installed. If this is the case, the microcomputer automatically prevents deployment of the front passenger airbag. The "Airbag Off" indicator lamp in the centre console illuminates to confirm that the antennae and transponder have exchanged signals correctly.

Electronically Controlled Automatic transmission
The optional electronically controlled five-speed automatic transmission independently adapts the shift characteristics to the current driving situation and the driver's own wishes. When cornering, or on uphill and downhill inclines, the transmission's electronic unit alters the shift points automatically to prevent sudden gear changes which could otherwise hamper handling. Continuous comparison of data from various sensors with stored target values allows the transmission to adapt to the current situation promptly. Furthermore, the electronic unit monitors the movements of the accelerator pedal to work out how quickly and up to what speed the driver would like to accelerate. The torque converter lock-up also activates at low speed, thereby helping to reduce fuel consumption. This operates with a continuous computer-controlled slip, which de-couples the link between the engine and transmission just enough to eliminate any irksome vibrations. The winter program can be activated by pressing a button on the centre console. This makes pulling away on icy or snow-covered roads far easier. The transmission's winter program also comprises a second reverse gear with a longer ratio.

BAS
Brake Assist
When a sensor on the brake pedal detects that the driver is braking very suddenly and hard the system automatically delivers the maximum pressure to the brake rotors.

Belt force limiters
Mercedes-Benz has equipped e.g. the C-class (W203) sports coupé with belt tensioners for all seats as standard, which combine with the belt force limiters and airbags to significantly reduce the strain exerted on the chest region of passengers in the event of an accident. The belt force limiter is located inside the inertia reel and comprises a torsion bar, which turns slowly when a force exceeding a pre-determined level acts on the belt strap, thereby carefully reducing the locking effect of the inertia reel. Due to the force limiter, the inertia reel seat belt slackens again after exceeding a certain force threshold which reduces the degree of force exerted by the seat belts on the occupants.

Bi-Xenon
The headlights are linked to the GPS-system. So they shine into corners and the headlights are dipped automatically when towns are entered.
Known from the later Citroen DS models.

CDI - Common Rail Direct Injection
With diesel engines fuel pressure of up to 1.350 bar is maintained throughout a single line - the common rail - and distributed to the injector nozzles.
Non-CDI diesel engines use separate lines to the individual cylinders with lower pressure.

Central display
With the aid of the central display in the instrument cluster, drivers are able to program individual settings, in order to tailor the convenience and display functions to their own individual requirements. Once entered, the settings are permanently active and do not require any more buttons to be pressed by the driver. Settings are entered using the standard multi-function steering wheel which is linked to the central display, the car radio and the car phone. Lightly pressing the lower left button on the steering wheel is enough to call up the main "Settings" menu in the display. Here, over 50 individual settings can be programmed by selecting one of five separate menu options. Further information, instructions and data also appear in the central display in accordance with the stored settings: the trip meter and total distance odometer, the display for the audio or telephone function currently selected and the instructions from the navigation system, information from the in-vehicle trip computer as well as any fault messages.

Comand - Cockpit Management and Data System
Comand is the combination of car radio, cassette player, sound system, navigation system, telephone, clock and tv system.
Was first available in 1998 in the new S-Class (W220).

The very latest communications technology in the form of the Cockpit Management and Data System, known as COMAND for short, is now available for the first time for the C-class sports coupé, as an item of optional equipment. COMAND is a car radio, navigation system and CD player in one, as well as acting as the command centre for all audio, telematics and telecommunications equipment. The driver can either operate these functions directly from the COMAND unit in the centre console and read off the necessary operating information from the large colour display, or can enter instructions using the keys on the multi-function steering wheel. The central display in the instrument cluster and the COMAND display in the centre console are linked, but can also be used separately. The individual functions are selected by the driver by pressing the keys on the left of the COMAND system's colour display. More detailed instructions are given mainly by using the combined rotary/push-button on the right of the control panel. This button is used to highlight different menus on the display which can then be activated by pressing the button. The CD player is located above the colour display. It is used both for storing data from the CD-ROM for the navigation system as well as for playing audio CDs.

Common Rail
Modern injection system for diesel engines. Diesel fuel is injected under high pressure (ca. 1.350 bar) from a common rail for all cylinders. Advantage is lower fuel consumption, smoother run and cleaner burning of the fuel. Originally developed by Marelli (FIAT), further developed by Bosch.

The sophisticated common rail injection system from Mercedes, as featured e.g. in the C-Class (W202, W203), E-Class (W210) and S-Class (W220) CDI variants, represents the ideal compromise between economy, torque, ride com-fort and durability. Whereas conventional direct injection diesel engines need to build up the fuel pressure over and over again for each injection cycle, pressure in the CDI powerplant is built up independently of the in-jection sequence and is constantly available in the fuel line. The 'common rail' which precedes the cylinders serves as a pressure reservoir and distributes the fuel to the injectors at a constant pressure of up to 1350 bar. Based on the instructions from the electronic engine management unit, high-efficiency solenoid valves in the injectors govern both the injection timing and the quantity of fuel injected for each cylinder combustion chamber individually, in order to match current requirements. In other words, pressure build-up and fuel injection take place quite independently of one another, which is the key advantage of the common rail system over conventional processes. Pilot injection in CDI diesel engines can be governed just as flexibly to match current requirements as the main injection stage; a few milliseconds prior to actual injection, a small quantity of diesel fuel flows into the cylinders, ignites and thus preheats the combustion chambers. This improves conditions for the main injection, which has a positive effect on combustion noise and nitrogen oxide emissions.

Distronic
A distance-controlling tempomat operated by radar automatically keeps the correct distance to the car ahead.

Dyn APS
Dynamic Autopilot System
The route calculation of the navigation system takes into account the actual traffic news like traffic jams and detours.

Dynamic route guidance
To initiate dynamic route guidance, in conjunction with the car phone the COMAND system or Audio 30 APS car radio (optional equipment) sets up a link to Tegaron Telematics. This company evaluates the information gathered by the road data service, which monitors the traffic situation on Germany's motorways by means of some 3800 infrared or ultrasonic sensors. Using the SMS Short Message Service of the mobile radio network, Tegaron transmits digitised tailback warnings at regular intervals to the navigation system in the car, which than takes traffic reports into account for its own route guidance and, if necessary, recommends diversions to avoid tailbacks. Dynamic route guidance via the mobile radio network is already up and running in Germany and will soon be made available in other European countries. COMAND and Audio 30 APS also feature a second method of receiving digital traffic data for individual route guidance, which makes use of the Radio Data System (RDS) and the Traffic Message Channel (TMC). Radio stations trans-mit inaudible FM signals which COMAND decodes and evaluates; these signals contain tailback reports which are derived from induction strips in the road surface or are issued by the police. This information corresponds to the traffic reports of the normal (audible) radio programme and is free-of-charge. RDS-TMC is in operation across Europe. Dynamic navigation using this technology is currently available in Germany, while preparation work is underway in other European countries.

EHB
Electrohydraulic Brakesystem
Sensors measure the pressure applied to the brake pedal by the drivers foot and give the necessary pressure via the hydraulics to the brake rotors. Advantage: More stability, faster response, shorter stopping distance.

Ellipsoid firewall
As with the S-class (W220) and the CL (C215) flagship coupé, the engineers at Mercedes have also developed a new, standard firewall concept for the C-class (W203) sports coupé which offers the passengers even more safety – the ellipsoid firewall. The name of this assembly stems from the way it curves towards the front. It consists of six different individual components with different panel thicknesses. The engineers have thus been able to adapt the material to the actual load exerted and have achieved a perfect combination of lightweight design and crash safety. The ellipsoid firewall is connected to the front side members; it can absorb extremely high loads and can distribute the impact forces evenly over a large area to prevent the force of the impact reaching the passenger compartment.


ESP - Electronic Stability Programme (ESP®)
Sensors early detect the swerve of the car`s rear or the actual danger of swerving and brake the wheels in diagonal order to bring the car back to the "right" direction.

Since 1994, Mercedes-Benz has been making a key contribution to improving safety out on the road with its active driving safety system, the ESP® Electronic Stability Program. The standard ESP® system governs the brake forces acting on the front and rear wheels in such a way as to reduce the risk of skidding and to help the driver to keep things better under control in critical situations. The system consolidates the technology of the anti-lock braking and the acceleration skid control systems with a whole series of additional sensors which are needed primarily to calculate the degree of vehicle skidding. While the car is being driven, the ESP® computer constantly compares the actual vehicle handling variables with the computed target values. If the car deviates too far from the safe "ideal line", the system intervenes in a split-second and follows a specially developed logic to correct the car's course using two different methods: precision application of the brakes at one or more wheels and/or reduction of the engine torque. ESP® can correct both driver errors and as well as skidding induced by slippery or wet surfaces, loose chippings or other adverse road surface conditions, where motorists would otherwise have very little chance of correcting the vehicle's course by steering or braking.

GDI
Gasoline Direct Injection
Direct gasoline injection into the cylinder as opposed to indirect injection into the manifold. So far in mass production used by Japanese carmaker Mitsubishi only. The advantage of GDI is a lower fuel consumption under partitial load circumstances.

GPS
Global Positioning System
Explanation to be added later

Keyless-Go
Instead of a conventional door key there is a chipcard which exchanges signals with the car. When the bearer of the correct chipcard comes close to the car it automatically unlocks the doors. To start the car the driver presses a knob on top of the gear lever.
Was first available in 1998 in the new S-Class (W220).

Linguatronic
Speech-based operation, so far only for the telephone which dials the desired number by speech instead of pressing buttons.

The state-of-the-art LINGUATRONIC voice-operated control system, which Mercedes-Benz was the first car manufacturer in the world to develop for operating the car phone, is available as an option to control the audio systems e.g. in the S- or C-class (W203). The systems registers the driver's commands by means of a microphone and then begins a short, interactive dialogue. A pleasant voice thus replies to the command "Dial number" with the request "The number, please". Once the driver has replied with the number and the command "Dial", the number will be dialled automatically. And the driver just needs to say the words "CD player" or "CD changer" and music will soon be coming through the loudspeakers. At the heart of LINGUATRONIC is a software program which is programmed for picking up algorithms to recognise speech and for the individual characteristics of the human voice. Consequently, the system can adjust itself to the current user's own voice and can even understand a variety of regional accents in English. To start off a dialogue with the system, which has an impressive vocabulary of 30 words, the driver just has to flick a special lever on the steering column.

PTS - Parktronic System
Sensors in the front and rear bumpers operating with ultrasound signals calculate the distance betweeen the bumper and the obstacle. The distance of the car to the obstacle is indicated by lights and sound. The system operates below 10km/h only.

Sidebag
The standard sidebags in the front are located in the doors above the armrests. Sidebags for the rear are available as an option. The asymmetrically designed air cushions have a volume of 13 litres each with the C-Class (W203) . In the case of a collision from the side, the sidebag rips open a seam in the door or side trim and inflates between the occupant and the door to prevent the occupant from being knocked against the door or side trim. This has a dual effect: as well as clearly re-ducing the loads exerted on the chest of the occupant sitting on the same side as the crash, the sidebag also limits upper body movement during the collision.

Six-speed manual transmission
Fitted as standard e.g. in the E-Class (W210) or C-Class (W203). The sixth gear is designed as a genuine drive gear in which the cars reach their top speed. Compared to the previous five-speed manual transmission, engineers at Mercedes were able to reduce shift forces by up to 25 percent by using more efficient synchromesh units featuring multi-cone synchromeshing. In practice, the gearshift is precise and light with short shift travel. Positioning the synchromesh for third and fourth gear on the countershaft reduces the shift forces for third gear yet further. The ease of 'diagonal' gearshifts from one shift gate to another makes sporty motoring even more pleasurable.

Supercharger
The supercharger of the 2.0-litre and 2.3-litre engines is located between the air cleaner and the intake manifold. It is driven directly by the crankshaft by means of a separate poly-V-belt. The belt-driven supercharger functions as a type of fan which produces pressure back in the intake system. It does this by compressing the incoming air which then quickly exceeds the engine's normal intake capacity; this creates a build-up of air which then becomes tightly compressed before it has even reached the cylinders. This generates the so-called boost pressure, one of the fundamental criteria for more efficient cylinder charging and more effective engine aspiration. Owing to the optimal air throughput and the improved cylinder charging, the supercharged engine develops far greater torque than a comparable naturally aspirated engine. And what's more, thanks to the belt-driven supercharger, the engine succeeds in combining the torque characteristics of a six-cylinder engine with the fuel economy of a four-cylinder engine. Together with specialists from the Eaton company, Mercedes engineers have redeveloped the belt-driven supercharger and made numerous improvements to it. These include, for instance, a special plastic coating on both of the three-blade rotors inside the oval supercharger housing, which are offset by 60 degrees and rotate at speeds of up to 14,000 rpm without making contact with each other.

Tele-Aid/TELEDIAGNOSIS- Telematic Alarm Identification on Demand
After a crash an emergency call via car integrated cellular telephone is released automatically.

Following a collision, the optional TELEAID emergency call system automatically transmits an emergency call via the car phone to alert the rescue services. The SOS signal includes important information such as the time, the licence plate number, the vehicle model and its precise location. TELEAID works in conjunction with GPS (Global Positioning System), whose satellites transmit digital bearing signals to the GPS receiver in the car. Depending on the type of crash, the emergency call transmitter is automatically activated by the standard crash sensor, which is also responsible for deploying the airbags and belt tensioners reliably. After issuing the emergency call, TELEAID automatically sets up a telephone link to the operations headquarters of the local police force. By pressing a button in the interior, the car's occupants are also able to issue the emergency call signal manually at any time. TELEAID currently operates in Germany and in the United States, and will be introduced successively in other countries too. The new telematics service TELEDIAGNOSIS uses the same technology as TELEAID: if the vehicles does break down, the driver just needs to push a button on the receiver of the car phone and the system will contact the central Customer Assistance Centre (CAC) of Mercedes-Benz, whose advisers will then be able to talk to the motorist by radio-telephone. As well as issuing the call, the system also transmits all the relevant data to the centre, including the vehicle and engine model, year of manufacture, engine temperature, battery voltage, odometer reading as well as any malfunction and warning messages currently stored. Finally, the system also transmits the pre-cise location of the car so that the service technicians can get to the site of the breakdown more quickly and reliably.
 

THERMOTRONIC luxury automatic climate control
The new THERMOTRONIC luxury automatic climate control, which is available e.g. for the C-class (W203) sports coupé as an optional extra, is controlled by computer, based on various sensor signals indicating the interior and ambient air temperature, air humidity, sunray transmission and pollutant levels in the outside air. Air in the interior is furthermore kept clean by a large particle filter and two activated charcoal filters, which absorb odours and pollutants in the air. The driver and front passenger are able to set air distribution and temperature separately, while passengers in the rear benefit from two additional ventilation nozzles in the rear section of the engine tunnel trim. The individual climate control settings are stored and transmitted to the electronic ignition key, ensuring that THERMOTRONIC will start with the same program settings the next time the vehicle is driven.

Three-link front suspension
A new front suspension design makes a decisive contribution to the dynamic handling of e.g. the C-class (W203) sports coupé: the design used is a three-link suspension with McPherson suspension struts. As well as precise wheel location, the primary benefit of this new design is that it compensates vibrations resulting from tyre imbalance or brake force fluctuations more effectively than a rigid wishbone suspension. Furthermore, a larger crumple zone is available in the event of front-end collisions, so the front of the vehicle can absorb greater impact energy than previously. The suspension struts also fulfil a dual function, as in addition to axle springing and damping, they also play an active role in front wheel location. The suspension struts consist of cylindrical coiled springs, twin-tube gas-filled dampers and enlarged head bearings. The standard torsion bar stabiliser is connected to the suspension struts via a linkage mechanism. When cornering at speed, special rebound buffer springs at the front shock absorbers reinforce the effect of the stabiliser, ensuring that the extremely dynamic handling of the sports coupé is not at the expense of ride comfort.

TIREFIT
Some MB`s like the C-class (W203) sports coupé comes as standard with the tyre sealant TIREFIT– a collapsible tyre is also available at no extra cost. There are very good reasons for omitting a spare wheel. For instance, statistics have shown that on average, motor-ists in central Europe are only unlucky enough to get a flat tyre every 150,000 kilometres. This equates to ten to twelve years of motoring without ever needing the spare wheel. The TIREFIT set takes up very little space in the boot and, including the electric pump, only adds 2.2 kilograms to the weight, some 
89 percent less that a conventional spare wheel. Furthermore, TIREFIT frees up the spare wheel recess to be used as additional stowage space. The tyre sealant is based on a special latex solution, which is particularly straightforward and clean to use, without the need for any tools or a jack. The sealant is pumped through the tyre valve, the tyre is inflated using the electric air pump and the car can then be driven at a speed of up to 80 km/h. The sealed tyre must be replaced with a new tyre at the next Mercedes workshop.

VNT turbocharger
The turbocharger in the C 220 CDI can alter the angle of its vanes to match the current engine load in order to use the maximum possible amount of exhaust energy for compressing the intake air and for building up the boost pressure. This is made possible thanks to a variable nozzle turbine, known as VNT for short. This allows the system to set the optimal boost pressure for all driving situations; at low engine speeds, the vanes reduce the cross-section of the air flow to optimise the in-flow at the turbine which in turn increases boost pressure. At higher engine speeds on the other hand, the cross-section is enlarged and the speed of the turbocharger drops. In this respect, the VNT turbocharger is superior to conventional turbocharger systems for diesel engines because the entire exhaust energy can be used for generating boost pressure at all times. Further benefits of the variable turbo-charger control include improved cylinder charging and therefore higher torque.

VTG - Variable Turbocharger Geometry
The turbine shovels of the turbocharger are electrically adjustable. Electric adjustion allow a rapid adjustion speed leading to a better air supply than with other shovel adjust techniques.

Windowbag
The standard specification windowbags e.g. in the C-class (W203) sports coupé each comprise four chambers with a total volume of around 25 litres. In the event of a crash, the 1400-millimetre-long air cushion inflates within a mere 25 milliseconds to form a curtain in the interior from the front to the rear roof pillar. This provides a flat protective surface for the heads of both the front and rear-seat passengers, regardless of height or which seat they are in. Normally, the windowbags are concealed be-hind the interior trim of the roof frame and of the C-pillars, which press inwards when there is a collision so that the windowbags can inflate. The C-pillars also house the gas generators for the windowbags.
 

Almost all explanations by DaimlerChrysler, edited by MBEP webmaster


Special thanks goes to 
Bjørn Erik Seeberg, Carsten Thidemann and Daniel Gillitzer 
for pointing me to errors in earlier versions of this page!

Last revised: November 20th 2000  Visits since January 5th 2000..... [Sign Guestbook]
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