A-Pillar

A-pillar is the roof support on either side of a car's windshield. A-Pillars are also used to reinforce the upper side of the roof so not does it support the windshield, but it also protects the driver in case of an accident and or if the car rolls.

AAR

Automatic Air Recirculation - Integrated into the air conditioning, makes sure that pollutants in the air are not able to get inside the car. The system is able to recognise, for example, carbon monoxide, nitrogen oxide and ethanol, switching the automatic air conditioning to air recirculation for a limited period as soon as the concentration of harmful substances reaches a certain limit.

ABS

Anti-lock Braking System prevents the wheels from locking up during braking. Even under strong braking, the car remains steerable and controllable. This can help the driver avoid an obstacle without having to release the brakes first. When ABS is activated, the driver will notice a slight pulsation of the brake pedal.

ACC

Adaptive Cruise Control - Works just like a conventional cruise control system - until it detects a car in front of it. Sensors detect that you are approaching a car ahead. The system then automatically eases off the throttle or even gently applies the brakes to maintain a constant safe distance (which you can adjust) behind that vehicle. As soon as the vehicle pulls into another lane, ACC accelerates, smoothly and progressively, to your original chosen speed.

ACD

Active Center Differential incorporates an electronically controlled hydraulic multi-plate clutch. An ECU optimizes clutch cover clamp load for different driving conditions, regulating the differential limiting action between free and locked states. The result is improved steering response together with better traction. ACD provides three modes — Tarmac / Gravel / Snow — to enable quicker control response for changes in road surface. A single ECU provides integrated management of both ACD and Super AYC components.

Active charcoal filter

Absorbs vapor from the fuel tank and prevents it from escaping to the atmosphere. It is particularly important on cars equipped with a catalytic converter, since these use unleaded fuel which may contain a higher proportion of dangerous hydro-carbons.

Active Head Rests

Pyrotechnically triggered, the Active Headrests 'catch' the head before it can suffer the effects of whiplash, by moving into position as soon as a rear end impact is detected.

Active Seat Ventilation

Ensures that air circulates throughout the seat constantly, removing moisture and helping prevent discomfort or driving fatigue. A total of nine axial flow fans are integrated into the high-quality foam padding inside the seat: four in the backrest and five in the seat. The fans draw fresh cabin air into the seats and channel it through an air-permeable middle layer, distributing it evenly throughout the seat. Special perforations in the upholstery allow it to move through the leather, keeping perspiration to a minimum. The three-speed fans can be controlled using a switch on the central console or a control on the seat itself, depending on your Car model.

Active Steering

Active Steering still has a mechanical steering column that permanently connects the steering wheel and front wheels. This guarantees that the steering continues to operate even if the auxiliary systems malfunction or fail completely. The benefit is on the improvement of road safety in critical driving situations such as oversteer. Here Active Steering intervenes with corrective measures to attenuate the yaw as it occurs, thus stabilizing the vehicle al-most imperceptibly to the driver and passengers.

Active Suspension

An extremely sophisticated, computer controlled Suspension system that uses powered actuators instead of conventional Springs and Shock Absorbers. The actuators position a car's wheels in the best possible manner to deal with road disturbances and handling loads.

Adaptive Brake Assistant

A practical addition to the Adaptive Cruise Control (ACC) system. The radar sensors at the front of the car measure both the distance to the vehicle ahead and its current speed. If the vehicle ahead stops suddenly, or if an obstacle appears in the lane ahead, the Adaptive Brake Assistant calculates whether emergency braking must be applied, and the necessary amount of brake pressure. Having calculated the optimum braking power, the system activates the brakes only after the driver has applied the brake pedal. It also gives the driver warning signals: depending on the model, visual warnings are provided on the dashboard or on the Head-Up Display. The type of warning differentiates between a cautionary signal (e.g. if the vehicle ahead is too close) or an acute alert to a critical situation (e.g. the vehicle ahead brakes suddenly).

Adaptive Drive

BMW's innovative chassis control systems, Dynamic Drive and Variable Damper Control (VDC) work closely together to deliver an outstandingly smooth ride and enhanced agility. Sensors in the BMW permanently monitor vehicle speed, steering-wheel position and the pitch and yaw forces acting on the chassis. Using this data, the system precisely adjusts the stabilisers and the dampers, changing their settings quickly and accurately. This coordinated interaction of dampers and stabilisers counteracts the forces that cause the body to roll or sway. The vehicle hugs the road, delivers neutral self-steering behaviour, outstanding agility and shorter braking distances.

Adaptive Headlights

As the driver turns the wheel, the central computer uses data on the vehicle's steering angle, yaw rate and speed to calculate the perfect angle for the headlights. Electric motors then swivel the xenon modules to the perfect position. This delivers more light onto the road, resulting in significantly better vision at night.

Adaptive Idle Control

Self-adjusting or adaptive idle control is a function provided by the DME III engine management system and by DDE. It ensures that the engine always idles at a speed, such as when the air conditioning cuts in, the power steering is turned or a gear is selected at the automatic transmission, but also other influences such as air pressure and temperature changes, reduced or increased friction in the engine as a result of wear etc., are all accurately identified and allowed for.

ADB-X

Automatic Differential Brake gives the driver all the advantages of a fully automatic differential lock. ADB-X is directly connected to and controlled by Dynamic Stability Control (DSC). As soon as ADB-X recognises that a wheel is about to spin, DSC slows the wheel down until optimum grip is re-established. At the same time, the power of the engine is distributed among the remaining wheels. Depending on the traction required, ADB-X can control the brakes on all four wheels individually. If the available brake power is not sufficient, for example on an extremely slippery surface, the ADB-X control system can reduce engine power accordingly, guaranteeing optimum power transmission to all four wheels on virtually all kinds of surfaces.ADB-X also works when the driver has switched DSC off, while the automatic intervention of the brakes still ensures optimum traction and a temperature control system which protects the brakes from overheating.

Advanced Engine Material - Friction and Inertia

1. Aluminium pistons and cylinder liner (including Nikasil and FRM) Whether an engine responsive and high-revving depends very much on the inertia of reciprocating parts, i.e., Crankshaft, pistons and connecting rods. While crankshaft material is still bounded to steel for the reason of strength, pistons of high-performance engines are usually made of aluminium. The lighter the pistons, the higher rev and power the engine obtains. Using alloy pistons is not very costly, what prevent most mass production all-alloy engines from using them is the friction generated between pistons and cylinder walls. It is commonly known that the contact between two aluminium surfaces results in high friction - much higher than between cast-iron and aluminium. Therefore many engines with aluminium block have to employ cast iron pistons.

Advanced Engine Material - Weight Reduction

1. Aluminium Head and Block All-aluminium engines (head and block made of aluminium alloy) are increasingly popular. Mass production all-alloy engines such as Rover K-series, BMW M52 straight-six, Nissan VQ-6, Jaguar AJ-V8, Mercedes V6 / V8, GM LS1and Northstar V8, Peugeot's 2-litre four and GM's new four-cylinder family proved that aluminium block will spread to nearly all cars in the near future.

Aerodynamics

The branch of mechanics that deals with the motion of gases (especially air) and their effects on bodies in the flow. In car design the positive and negative lift of the airflow is studied in wind tunnels. Negative lift is preferred to press the vehicle closer to the ground. Car air resistance is also studied.

Aerodynamic Drag

The drag produced by a moving object as it displaces the air in its path. Aerodynamic drag is a force usually measured in pounds; it increases in proportion to the object's frontal area, its drag coefficient, and the square of its speed.

AFS

Active Front Steering - provides an electronically controlled superposition of an angle to the steering wheel angle. This additional degree of freedom enables a continuous and driving-situation-dependent adaptation of the steering characteristics. Features like steering comfort, effort and steering dynamics are optimized and stabilizing steering interventions can be performed.

AGM

Absorbant Glass Mat - batteries are able to withstand a much greater load than conventional lead acid batteries. In an AGM battery, the acid is held in micro-glass-fibre mats between the individual layers of lead, the battery thus remaining able to store energy over a long period even when charged and discharged regularly.

Air-Fuel Mix

Ratio by weight of air and fuel in the engine's cylinder.

Air Bag

A device, that inflates in a frontal collision in order to protect the driver from impact against interior vehicle components. When triggered, the air bag inflates in approximately 30 milliseconds.

Air Dam

A spoiler below the front bumper to reduce aerodynamic lift, drag and turbulence by diverting airflow around, rather than under, the vehicle. It also improves air flow through the radiator and air conditioning condenser.

Air Filters - Paper

Air filters found in most 'production cars' are made from paper (as filtration) and plastic as the body. Paper filters are a stacked matting of fibers creating a random weave approximately 1/2mm thick, and rely on the "screening" effect to stop dirt particles. Airflow per square inch is so poor that the paper must be pleated using many feet of material to make a filter. All dirt or dust particles must be caught on the surface or not at all. Each time a particle is caught, it stops up a hole. From the moment you start your engine, you have a rapidly decreasing air flow rate. Paper also has two other big drawbacks for off-road use. Any moisture reaching the element causes the fibers to swell, reducing airflow even more. Another is the possibility of rupture. Paper is not a very strong material, especially where it is creased to form each pleat. Intake manifold backfires, or cleaning attempts with compressed air, usually rupture the paper leaving the filter ineffective.

Air Filters - Reusuable

As an alternative to Paper Filters there are also a large number of aftermarket reusuable air filters and manufacturers, each having their own claims, pro's and con’s. One of the biggest pro's would have to be the 'reusable' factor that a lot of them have to offer. Not only does this lower the cost of maintaining your car, it also eliminates another item you have to replace at your next service.

Air Injection

A system that injects air into the exhaust ports of the engine for combustion of unburned hydrocarbons in the exhaust gases, thus producing "cleaner" exhaust emissions.

Air Intake

The quantity and quality of the air being mixed with fuel is of vital importance. It helps determine the longevity of an engine, as well as an engine's power and smoothness when running.

Air Scoop

An aerodynamic device or opening used to duct cool outside air to some part of the car generally the engine air intake, the brakes or the radiator.

ALC

Adaptive Lighting Control - Enhancement of active safety at night, the lights turning with the steering to improve driver visibility and thus adjusting infinitely to the steering angle. The two bi-xenon headlight units are masterminded in their position as a function of the steering wheel angle, the yaw rate and road speed, thus illuminating the road ahead clearly and brightly in a bend. The driver activates the adaptive headlights by switching the headlights in the "Automatic" position, the headlights thus moving in the desired direction as soon as the car itself starts to move. When the car is at a standstill with the wheels locked to the left, the headlights have to be pointing straight ahead in accordance with road traffic regulations (with the opposite setting in left-hand traffic) in order to avoid any dazzling of oncoming traffic. When backing up, in turn, the adaptive headlights remain inactive.

Alternative Fuels

Because of concerns about fossil fuel reserves, alternative fuels originally gained attention in the 1970s as potential substitutes for petroleum-based fuels. These shortages did not materialize but the environmental advantages of alternative fuels have sustained public interest. The fuels of greatest interest are reformulated diesel fuel, compressed natural gas, alcohols, and biodiesel.

Alternator

The alternator uses the principle of electromagnetism induction to produce voltage and current. A magnet, called a rotor, is rotated inside a stationary looped conductor, called a stator, to generate a voltage.

Alternator - Voltage Regulator

The voltage regulator controls the field current applied to the Alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery. When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery.

Anti-Roll Bars

Stabilizer bars are part of a car's suspension system. They are sometimes also called anti-sway bars or anti-roll bars. Their purpose in life is to try to keep the car's body from "rolling" in a sharp turn.

Anti-Submarining Protection

Submarining is the name given to the problematic tendency to slide out under a seatbelt in an accident: the forces make the body "dive" under the lap section, towards the dashboard and footwell. Serious abdominal, pelvic and spinal injuries can be the result. In a frontal collision or emergency braking, the sudden deceleration can cause you or your passengers to slide down under the lap section of the seatbelt, increasing the risk of injury significantly. Anti-submarining protection helps eliminate this danger by holding you firmly in your seat.

Antifreeze

Any of several substances (typically ethylene glycol) mixed with water and added to the car's cooling system to prevent freezing of the coolant in winter. It also inhibits formation of rust and other deposits that would tend to clog the radiator and coolant passages, thus reducing cooling efficiency.

API

American Petroleum Institute - performance standards are indicated with the abbreviation API SJ or API CE : * the first letter designates the type of engine (S = gasoline and C = diesel), * the second letter designates the performance level (for gasoline engines, etc.). Lubricants must successfully complete four tests to achieve API performance levels; these tests take into account : * the rise in the temperature of engine oils in service ; * the lengthening of the period between oil changes recommended by manufacturers ; * efforts to achieve engine performance ; * increasingly stringent environmental protection standards ;

API - Diesel Engine Classification

CC : For diesel engines with normal service description (lightly supercharged) and gasoline engines. CC oils are very detergent and dispersant and offer good protection against wear and corrosion. CD : For diesel engines under heavy use, high speed and subject to high effective mean pressure due to a turbocharger. CD oils are very detergent and dispersant and offer good protection against wear and corrosion. CDII : For two-cycle diesel engines conceived for extreme service. Strict limitation of deposits and wear. CDII oils meet requirements for the CD class above and also satisfy standard two-cycle GM engine tests carried out on a Detroit 6V53T. CE : For turbocharged diesel engines under heavy use dating from 1983. Aimed at high-powered, high-speed engines and also at slow motors which develop high power. CE oils can replace CD oils in all engines. With the properties of CD oils, these oils are more effective in limiting oil consumption, deposits, wear and oil thickening. CF : Same as CE with the addition of a test for micro-oxidation. Reinforced protection of pistons and piston rings. CG : For diesel engines under heavy use. They fight deposits on pistons, wear, corrosion, foaming, oxidation and the accumulation of soot at high temperature. These oils respond to the needs of engines adapted to 1994 emissions standards. CH : For diesel engines adapted to 1998 emissions standards. These oils are meant to guarantee engine life under the most severe conditions. They allow for more time between oil changes.

API - Gasoline Engine Classification

SD : For the gasoline engines of passenger cars and trucks dating from 1968 to 1970. An SC oil should offer protection against the formation of deposits at high (detergency) and low (dispersion) temperatures. Additional protection is also required against wear and rust. SE : For the gasoline engines of passenger cars and trucks dating from 1971. The SE oils can replace SC oils. Compared to the preceding category, SC oils offer better resistance to oxidation and the formation of "cold sludge" at low temperatures. The engine is also better protected against rust. SF : For the gasoline engines of passenger cars and some trucks dating from 1980. SF oils can replace SE and SC oils. SF oils are better than SE oils as concerns resistance to ageing and protection against wear. SG : For gasoline engines of passenger cars and some trucks dating from 1989. SG oils can replace SF, SG, CC, SE or SE/CC oils. SG oils have better results than SF oils in resisting the formation of deposits, protection against wear and resistance to corrosion. SH : Same as SG but more stringent test conditions. SJ : At SH level, but developed in accord with the API certification system following multiple test criteria.

API - Transmission Classification

API-GL-1 For axle transmissions with spiral gears and worm screw and certain manual transmissions. May contain additives: antirust, antioxidant, antifoam and an agent which lowers the point of solidification. API-GL-2 For worm-screw transmissions in which a GL-1 oil is insufficient. API-GL-3 For axle transmissions with spiral gears that function at moderate speeds and medium service for which a GL-1 oil is insufficient. API-GL-4 For spiral-gear transmissions and special hypoid transmissions for vehicles which operate in high speed conditions at low torque or at low speed at high torque. Anti-wear and extreme pressure additives are often integrated. API-GL-5 Same as previous case but under high-speed conditions generating extremely low torque and low speed at high torque. Anti-wear and high pressure additives are often used.

ASCT

Automatic Stability Control + Traction, prevents the rear drive wheels from spinning and ensures optimum traction and driving stability. Whenever the wheels threaten to spin, for example when setting off or when accelerating out of a bend, engine management reduces drive power accordingly. Should this not be sufficient to re-stabilise the car, the rear wheels are slowed down (depending on the load) either individually, one after the other, or both together by the brakes until the car regains traction. This control process takes place within milliseconds, the driver being informed when ASC+T is activated by a light flashing on and off in the instrument panel. And in order to generate extra wheel spin when required, for example when "rocking" the car out of snow, you can deactivate the ASC+T function.

ASF

Audi Space Frame is a high-strength aluminium frame structure into which the panels are integrated so that they also perform a load-bearing function. In conjunction with high-strength aluminium sheet, the aluminium body is characterized by exceptional stiffness and above-average crash protection, yet at the same time by substantially lower weight. Comparison: an Audi A2 weighs 895 kilograms, about 150 kg less than a comparable compact with a conventional steel body.

ASR

Anti Slip Regulation can increase both comfort and safety, particularly on surfaces with differing coefficients of friction or on slippery roads. It makes smooth starts and acceleration possible through all speed ranges without wheel-spin or fishtailing.

ATM

Adaptive Transmission Management - integrates data input from the accelerator pedal and the engine management system. By analysing the timing and manner that the driver applies the accelerator, ATM autonomously learns the driver's style - noting, for example, whether the engine brake is often used, or if a gear is downshifted to accelerate out of curves. This pattern is continuously monitored, so that ATM always adapts to the style of the current driver. In addition to the driver's individual style, ATM analyses the prevailing driving conditions: driving in winter or in mountainous areas, ATM shifts gears differently to driving in normal conditions. Stop-and-go traffic or winding roads are recognised. This results in fewer and more precise gear shifts, letting you fully focus on the dynamic performance of your vehicle.

Autobeam

A camera integrated in the rear-view mirrors monitors ambient brightness and traffic conditions, and can detect the headlights of approaching vehicles up to 1000 metres away and the rear lights of vehicles ahead up to 500 metres away. The system switches the headlights from full beam to dipped beam automatically. As soon as the other drivers are no longer in danger of being dazzled, the system automatically switches up to high beam again. Driving at night with Autobeam relieves the driver of the need to constantly adjust his / her headlight's beam and gives a significant boost to driving safety. There's no danger of forgetting to return the headlights to high beam on the open road, so the driver is always assured of the best possible illumination of the road ahead. The system also automatically switched to low beam when you enter an area with street lighting. Autobeam is activated by pressing a button on light control switch.

Automatic Transmission

An automatic transmission is much easier to drive than a Manual Transmission, because you don't have to use a Clutch pedal or gearshift lever. An automatic transmission does the work all by itself. The first automatic transmission appeared in 1939. Automatic transmissions automatically change to higher and lower gears with changes in the car's speed and the load on the engine. These transmissions are also aware of how far down you have pushed the gas pedal, and shift accordingly.

Automatic Transmission-Electronic

Electronic sensors send information to a microcomputer that selects the optimum shift characteristics and the proper gear for varying road conditions. These electronic sensors measure vehicle speed and engine load.

Automatic VS Manual Transmission

What is the difference between automatic and manual transmissions? In a vehicle with manual transmission, the driver must manually shift from gear to gear. Each shift in gears signals a change in the ratio of wheel revolutions to turns of the engine. By changing gears, the driver keeps the engine at its optimal performance level in the varying conditions. The clutch pedal in a manual transmission disengages the gears in the transmission which allows the engine to continually spin even when the wheels don't, allowing the driver to shift gears without damaging the engine. An automatic transmission vehicle contains neither a "gear box" as such, nor a clutch pedal. A planetary gearset automatically changes the gear ratios between the wheels and the engine to meet the optimal level of performance. Instead of a clutch, an automatic transmission contains a torque converter. When the engine speeds up, it feeds transmission fluid to the converter, which distributes more torque to the wheels.

Automotive Fluids

Vehicles require several fluids to operate and to stay in good condition, without oil your engine couldn't operate. Without coolant it would quickly overheat and burn itself up. Brake, transmission and power-steering fluids are all liquids used in sophisticated hydraulic systems, without which your car would be essentially undrivable. Through age and usage, all of these fluids eventually break down, deteriorate, become contaminated or leak out. It's important to check them frequently and also to check their condition for signs that they need to be replaced. If you find evidence of a fluid leak on your garage floor or in your driveway, you'll want to determine the source immediately. Letting a leak go unattended, and allowing a vehicle to continue to run with an insufficient amount of an essential fluid, can easily ruin an engine. In order to determine the source of the leak, it's helpful if you are familiar with the "healthy" appearance of each type of fluid. Aside from helping you pinpoint leaks, having a good idea of how each fluid should look when it's fresh and clean will also help you recognize signs that they are breaking down or becoming contaminated and in need of a change.

Auto Start Stop Function

Turns off the engine each time the vehicle comes to a complete halt - such as at traffic lights - and restarts it automatically. A reduction in fuel consumption is the result. The principle is simple: if the engine is not running, it cannot consume fuel. The Auto Start Stop function turns off the engine whenever it is not needed.

Auxiliary Lighting

This refers to any additional driving, fog or spot lights fitted to the car and used in conjunction with the existing high and low beam headlights.

AVS

Adaptive Variable Suspension - This advanced set up electronically monitors and adapts the suspension damping and steering to ensure optimal handling and ride depending on the driving conditions. It can also be switched to sports mode to give a more active and engaging driving feel.

AWD

All Wheel Drive - All four wheels are driven by the engine. AWD systems are superior to 4WD because (AWD) they can be used under any road conditions. AWD systems use a center differential to allow the front and rear wheels to rotate at different speeds. AWD provides better traction than front or rear-wheel drive cars.

AWD - 4Matic

All Wheel Drive - 4Matic With the arrival of six 4MATIC models, the Mercedes-Benz E-Class is set to become even more versatile and interesting from this autumn. The Stuttgart-based automotive brand combines the permanent four-wheel drive system in both saloon and estate versions with the powerful six and eight-cylinder engines. Thanks to its intelligent interaction with the Electronic Stability Program ESP® and the 4ETS traction control system, 4MATIC helps the driver to cope with critical situations in a safe and confident manner.

Axle

A shaft on which a wheel revolves or which revolves with the wheel. Also, a solid beam that connects the two rear wheels of the car. These structures support the vehicle and in some cases transmit torque to the drive wheels.

AYC

Active Yaw Control - System uses a torque-transfer mechanism in the rear differential. Under ECU control, the system operates to raise cornering performance by transferring torque between the rear wheels as dictated by driving conditions and so control the yaw moment acting on the car body. In an evolutionary step, switching from the use of a bevel to a planetary gear differential gave Super AYC the ability to transfer almost twice the torque between the rear wheels. As well as reducing understeer further, it delivers LSD-level traction. The use of a single ECU to integrally manage Super AYC with the ACD results in a synergism that makes both components operate more effectively than if they were under independent control.