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Keeping it short

The mysterious symbols of the car world

Nowadays, new devices are recognized only by their symbols, which can be difficult to understand outside professional circles

Pietro Paolo Marziali

Begun on the quiet about twenty years ago, this language has grown so much in every sector that sometimes an initialism has one meaning for a mechanic and another for a programmer.


Initialisms are now a part of today's language. They are a group of letters, the first letters of normal words, that allow written texts or conversations between professionals to be abbreviated. Begun on the quiet about twenty years ago, this language has grown so much in every sector that sometimes an initialism has one meaning for a mechanic and another for a programmer. On the other hand, the same device is called in different ways (resulting in different initialisms) by different industrial groups. We have indicated in our list when different initialisms have substantially the same meaning. The paternity of many initialisms is not clear and there are also specific symbols that were "invented" by a certain brand and used only by it, because they indicate the devices that it developed and patented. Even professionals find that it is not always easy to determine the meaning behind three or four letters. We can't dedicate the entire magazine to initialisms in the mechanical sector, also because technical developments lead to new ones being created in continuation, but we have made a list of the most common and already very numerous ones!.

ABA = Active Brake Assistant (also Hydraulic Brake Assistance). The device that increases braking power when the driver brakes suddenly and hard.
ABS = Anti-lock Braking System (also ALB) - The system created thirty years ago to prevent the wheels from locking during braking. It is mandatory on cars and trucks weighing over 3500 kg.
ACC = Adaptive Cruise Control - It maintains a set speed and has a mini-radar that keeps the distance from the car in front constant, braking if it goes below a certain safety level.
AdBlue = A generic name for aqueous urea solution; non-toxic and odourless, it is injected in SCR systems where it hydrolyzes into ammoniac.
AFL = Adaptive Forward Lighting - A device with different programs that directs headlight beams to give the best illumination depending on the road, speed or steering.
APF = Anti-Particulate Filter - It self-regenerates after a set distance.
ASL = Automatic Speed Limiter - synonymous with Cruise Control, it maintains a set speed and reduces power if it is exceeded.
ASR = Anti-Slip Regulation - (also Dynamic Traction Control, Automatic Stability Control) - A system that regulates traction and prevents wheel slip by removing power from the engine and/or by braking the wheel that is slipping.
AWD = All Wheel Drive (also 4WD) - It indicates traction on all four wheels. In trucks, it is an alternative to 4x4 or 6x6.


BDC = Bottom Dead Centre - The lowest point of the piston in the aspiration and combustion stage in both petrol and diesel engines.
Bi-xenon = A bulb that performs both dipped and full-beam headlamp functions by means of a shield that moves up or down in front of the bulb.
Blue Tech = a technology used to reduce toxic gas emissions from diesel engines (see AdBlue).
BSA = Blind Spot Assist (also Blind Spot Information System) - A device with sensors that reveal vehicles overtaking on the left or cyclists in the blind spot on the right.
BTL = Biomass To Liquid - a synthetic diesel derived from biomass, which is being assessed as an alternative to diesel oil.


CAN-Bus = Controlled Area Network - A system in which the data from various centres travel along a single cable and from which operating systems can collect the data of interest.
CDC = Continuous Damping Control - The control of suspension by means of electronically-controlled valves on the shock absorbers, which change responses in real time based on the data from each sensor.
CDI = Common-rail Diesel Injection (also CDTI, CTDI, DCI, JTD, TDCI) - The symbols use by various manufacturers to identify their own versions of common-rail injection systems.
CGI = Compacted Graphite Iron - Nodular graphite cast iron used for the block of certain new engines. It is nobler and lighter than grey iron.
CO = Carbon Oxide - A toxic gas generated by incomplete combustion. It is transformed into carbon dioxide by catalysts.
CNG = Compressed Natural Gas - The British symbol for methane, a gas widely available in nature but not renewable.
Cx = Aerodynamic Resistance Coefficient. The lower it is, the more aerodynamic the vehicle.

DRL = Daytime Running Light. Lights that come on during the day to improve vehicle visibility. Already used by many manufacturers, they will be mandatory in 2012. They are not to be confused with side lights.
dB = Decibel - A unit used in measuring the noise levels of trucks, vehicle interiors, tyres, etc. Distribution is hyperbolic.
DCPT = Diesel Catalyzed Particulate Trap - A particulate filter in EGR systems that works with a catalyzing component mixed with diesel.
DOHC = Double OverHead Camshaft - Indicates that the engine transmission has two overhead camshafts. This applies to petrol and diesel engines.
DPF = Diesel Particulate Filter - A continuously regenerating anti-particulate filter.


EBD = Electronic Brake Distribution - (also EBL) - The electronic distribution of braking power between axles. It replaced the mechanical valve.
EBS = Electronic Brake System - The electronic distribution of variable braking power to each wheel depending on its instantaneous grip.
ECU = Electronic Control Unit - A generic name.
EDC = Electronic Diesel Control - The first system by which the traditional mechanical injection pump is controlled by an electronic control unit.
EGR = Exhaust Gas Recirculation - A system that cools and returns a part of the combusted gases to the combustion chamber to reduce toxic emissions.
EEV = Enhanced Environmentally-friendly Vehicle - It also indicates the emission standards in the United States, which are even stricter than our Euro 5.
ESP = Electronic Stability Program (also DSTC, VDC, RSS, DTC, VSC) - They are synonyms for a vehicle stability system that applies the brakes to individual wheels when loss of steering is detected. It is integrated with ABS.
EVB = Exhaust Valve Brake (also J-Brake, Valve Engine Brake) - An auxiliary system in the braking system which opens the exhaust valve at the end of the compression stage. It was created by engineer Jacob.


FAS = Fatigue Alert System (also Anti-Drowsiness Protection) - A system with a camera that emits an acoustic signal when it detects that the driver's eyelid movement has slowed down.
FMS = Fleet Management System - The fleet management system connected between the company and the driver's onboard computer.
FUPS = Front Under-run Protection System. A bar under the truck bonnet which prevents a vehicle from being trapped in a head-on crash. It has been a legal requirement for only a few years.


GPS = Global Positioning System - US military satellites on a fixed orbit from which a good approximation of a vehicle's position can be received.
GVM = Gross Vehicle Mass - a more specific indication than GVW (Gross Vehicle Weight), meaning the maximum permissible weight of a vehicle.


HH = Hill Holder - A function that is part of ESP, it holds the vehicle even on a slight incline. It makes starting off again easier.
HUD = Head-up display. A system that projects the most important engine functions onto the windscreen, enabling them to be checked without taking the eyes off the road.


iQon = An onboard communication platform that uses Google's Android operating system to send and receive onboard information. The IT platform connects automatically to the Internet as soon as the car starts.


LED = Light Emitting Diode - A diode that emits a very bright light when crossed by an electric current. With almost unlimited duration and minimum consumption, LEDs are replacing tungsten and xenon lamps.
LGS = Lane Guard System - (also Lane Assist) - A device fitted with a video camera that warns drivers when they inadvertently leave the correct lane.
LPG = Liquid Petroleum Gas - Petroleum-derived gas (propane and butane) in liquid form contained under pressure in cylinders.
LSD = Limited Slip Differential - By locking the clutch, the device limits the free rotation of the differential when one wheel loses grip. It is used to get out of difficult situations.


MPV = Multi Purpose Vehicle (also SUV) - A lightweight vehicle for on- and off-road use.
A spacious interior with black being de rigueur for the exterior.


NiMH = Nickel-Metal Hydride - It is the most modern and profitable technology for making batteries for electric vehicles. The advantages over traditional accumulators are less weight, the ability to "store" more energy, and faster recharging.
Nm = Newton metre - A unit of engine torque. An alternative to kgm (kilogram metre) - 1 kg x m = 9.81N x m.
NOx = the chemical symbol for nitric oxide, a gas produced by engine combustion. Toxic.

OBD = On Board Diagnostics - A device for checking onboard electronics and AdBlue injection operation. It generally has an output for connection to an external PC which accesses the vehicle's operating data.

PDC = Pneumatic Damping Control - A system for controlling suspension that is simpler than CDC in which the response of the shock absorbers is guided by the pressure of the springs. It is suitable for vehicles like trailers that are not fitted with electronics.
PLD = Pumpe Linje Düse - The German symbol meaning pump nozzle or unit injector. It is the third electronic injection system developed by Bosch and is used by Mercedes.
PSS = Pre-Safe System - (also Pre-Crash System). This prepares the vehicle for an unavoidable accident. It activates seat belt tension, head rest position and automatically controls pedal activity.
PTO = Power Take-Off - A mechanically- or pneumatically-operated splined driveshaft on some off-road vehicles and trucks.


RDS = Radio Data System - An automatic function in advanced radios which enables local FM stations to be identified and to broadcast traffic information.


SCR = Selective Catalytic Reduction - An alternative to EGR. By means of a catalyst, it reduces toxic emissions from an engine, often with the addition of AdBlue.


TDC = Top Dead Centre - The opposite of BDC, it is the piston's highest point. The space above is the combustion chamber.
TDI = Turbocharged Direct Injection - A new direct injection system coupled with a turbocharger to improve engine power while reducing displacement (downsizing). TDI uses the PLD system. Compared to the 15-20 bar achievable by a normal injection system, TDI gives up to 800.
TMC = Traffic Message Channel - An alternative to RDS. Radio stations transmit traffic information which is received automatically.
TPMS = Tyre Pressure Monitoring System - It warns the driver when tyre pressures are low and is essential for run-flat tyres, which deflate very slowly. It is the same as DWS - Deflation Warning System.
TS = Twin Scroll - a turbine with two exhaust gas inlets which open in sequence to improve engine response and performance.
Unit Pump System - (also Electronic Unit Pump). An electronically-controlled modular pump-injector system. It is a rival of common-rail.


VTG = Variable Geometry Turbocharger - A turbine with vanes that can be oriented depending on engine revolutions to optimize performance.
VVT = Variable Valve Timing - The mechanical or hydraulic variable timing of one or both camshafts.


Xenon = The gas used instead of tungsten filaments in bulbs, which give a brighter, bluish light, last longer and consume less.
XPI = eXtra Pressure Injection - A common-rail injection system designed by Scania and Cummins to replace the Unit Pump System.


ZEV = Zero Emissions Vehicle - This generally indicates an electric vehicle. It is the dream for tomorrow.


4WS= Four-wheel steering. A new technology used by some top-range vehicles. Up to 60 km/h, it allows the rear wheels to be steered in the opposite direction to the front wheels. At higher speeds, both front and rear wheels turn to increase manoeuvrability and reduce roll.


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