Jargon buster ...

My jargon buster directory will help you unravel some of those technical terms you might find within my pages… they are laid out in alphabetical order to make life easier! I must have got the “bones” of them from somewhere, I apologise if they are yours and haven’t credited you …

AAR: Automatic air recirculation senses the quality of air being drawn into the passenger compartment and temporarily closes off the intakes if required.

ABC: Active body control is an electro-hydraulic suspension control system to reduce body-roll during cornering, while keeping a supple ride.

ABS (antilock braking system): Stops the wheels locking under heavy braking, allowing the driver to retain control and prevent skidding. As the wheels begin to lock up, sensors release and reapply pressure at a rate of up to 12 times per second. Now standard on all new, mass-produced cars worldwide.

ACC (active/adaptive cruise control): Maintains a safe distance between your car and the vehicle in front using a radar device in the front grille. Automatically brakes or slows the car down if it senses the car in front doing the same or increases speed up to a preset limit.

ACD: Active centre differential is the differential control used between the front and rear wheels to optimise four-wheel drive power split when driven hard.

Adaptive Automatic Transmission: Sophisticated auto transmissions that “learn” from the way you drive, and adjust their ratio changes to your style of driving, the nature of your journey, and your speed and power demands, in order to maximise on both performance and economy. Like humans, they can be confused — particularly if you suddenly decide to drive quickly, after a spell of slow driving. So take care!

AFL (adaptive forward lighting): Headlamps that adjust with speed and steering angle to give a broader spread of light and greater night visibility in all road conditions.

Air suspension: A type of wheel or axle suspension where an air spring is used in place of a conventional steel spring. This type of suspension maintains a given ride frequency, regardless of load, and is described as “road friendly.” When fitted on both axles of rigid vehicles, it can be used to raise and lower the chassis, simplifying the use of swap bodies.

Anti-roll bar: A simple mechanical means of minimising vehicle roll during cornering. The ends of a U-shaped bar are connected to the wheels of an axle, so that an upward movement at one end is transmitted to the other.

Approach angle: The angle between the ground and the lowest point of a vehicle, forward of a line drawn between the contact patches of the two front tyres. It is a measure of a vehicle’s ability to negotiate rough ground.

AWD: All wheel drive. Most cars are two-wheel drive with the engine driving through either the front wheels or the rear wheels. Driving all the wheels (four-wheel drive) gives much improved traction off-road or in mud/gravel, but at the expense of increased fuel consumption.

Axle capacity: This term usually refers to an axle beam, and indicates the maximum weight that it can safely carry, as declared by the manufacturer.

B Pillar: This is part of the vehicle structure between the front and rear doors.

Brake Assist: Variously named by the manufacturers, these safety systems detect “emergency” braking situations by the nature of the high pedal effort applied, and respond by increasing braking power to the maximum, using the ABS system to maintain stability. Can reduce emergency braking distances by as much as 25%.

Catalyser/Catalyst box: A small box fitted in the exhaust system, located close to the engine, to give fast warm-up and keep it hot. In diesel cars it generally uses a platinum-based catalyst matrix to eliminate some undesirable emissions — hydrocarbons and carbon monoxide. Failure leads to high emissions, and a probable MOT failure (in the UK). Average life five years plus. Replacement cost: R3,000 to R5,000.

CBC: Cornering brake control. A refinement facilitated by ABS, allowing you to brake while cornering, with the electronics controlling brake effort at each wheel for improved stability.

Chipping: Terminology applied to electronically tuning of an engine for more power and torque, usually by changing the software recorded in the “chip”, or by changing the actual chip in the ECU that controls fuel injection processes. Also applied (incorrectly) to tuning by use of add-on boxes that modify the signals sent to the fuel injection system by the ECU, rather than changing the actual software or chip.

CRDi: Common rail direct diesel injection. With conventional diesel engines, fuel is fed at low pressure to the injectors, where it is pressurised and squirted into a combustion prechamber. With common rail, the fuel is fed to the injectors via a common pipe (rail) at enormous pressure and the “injectors” simply act like valves, opening and closing to allow fuel directly into the combustion chamber.

Cruise control: A system that automatically regulates vehicle speed, making it possible to drive without continually holding down the accelerator pedal.

CVT: Continuously variable transmission is an increasingly popular form of automatic transmission that has either no steps at all (unlike a conventional automatic) or a number of fixed steps with steplessly variable ratios between them.

DDS (deflation detection system): Sensors on each tyre valve detect loss of pressure, giving the driver an early warning if the car suffers from a puncture or if the tyre pressure are low.

Departure angle: Angle made by rear of bumper or lowest part of the vehicle and the contact patch of the rear wheels.

Diff: Short for differential. This is a device that let’s a car’s wheels turn at different speeds, allowing it to go around corners smoothly.

Diff lock: A device used on some off-road vehicles. It stops the wheels turning at different speeds when you don’t want them to, by locking up the differential.

DOHC: Double overhead camshafts. One each for inlet and exhaust valves. Normally fitted to a high-performance car.

DPF: Diesel Particulate Filter — another exhaust system box that traps the particles that cause black smoke, and other finer particulate urban pollutants. Stores particles and then burns them off regularly by an added injection of fuel to raise the exhaust temperature to that at which the particles are burned off. Dramatically reduces diesel emissions, allowing them to conform easily with the latest Euro IV limits.

Drive-by-wire: Control by a system of electrical or electronic signals and sensors rather than by the conventional mechanical linkage of rods or cables.

DSC: Dynamic stability control is a suspension control system.

EBA (emergency brake assist): Adds extra force to the brakes when it senses you are braking in an emergency to reduce stopping distances significantly.

EBD (electronic brake force distribution): Adjusts brake force distribution to maintain optimim braking on all wheels (compensating for weight transfer). Works in tandem with ABS and helps prevent the rear wheels locking.

ECU: Electronic Control Unit. A mini-computer that controls all the vital processes of the modern car, including fuel injection, ABS braking systems, and many other functions like traction control and safety systems. More powerful and smarter than the computer that controlled the Apollo spacecraft!

EGR system: A method used to reduce emission levels — mainly nitrogen oxides — by recirculation of some exhaust gases back into the engine’s intake air. Frequent short runs and cold running can lead to gumming up and blockage of the vital EGR valve, resulting in poor engine response and lack of power, so it may need checking if that’s a problem in your car.

Electric power-assisted Steering: Now generally replacing hydraulic-assisted steering, on account of the fuel savings gained by not drawing power directly from the engine. Makes it easier to vary the steering effort with speed, and can also allow steering effort to be “tuned” by garages to your taste, or altered by a dashboard switch to give different levels of power assistance, as on Fiat Puntos and Pandas, where the “City” setting gives very low steering effort.

EFI: Electronic fuel injection is more efficient than a carburettor in controlling the flow of fuel into the engine. More power and lower fuel consumption is the result. Less maintenance is needed on an EFI system than on a carburettor, but an overhaul is more expensive. However, many last for the lifetime of the engine. The simplest EFI system is single-point, sometimes called throttle-body. It uses a single fuel injector. It is a low-cost system which lies about midway in efficiency between a carburettor and a full fuel-injection system. Much more common is multi-point fuel injection, which has an injector at each cylinder. Multi-point injection can be sub-classified into three types. In increasing order of efficiency, these are non-sequential, semi-sequential and sequential. Once only seen on expensive upmarket cars, EFI is used these days on all but a few of the cheapest new cars. Some older cars have a mechanical fuel-injection system, or a hybrid mechanical-electronic one, but these can be troublesome as they get old.

ENCAP: European new car assessment programme. This stringent European vehicle testing programme’s safety ratings are topped by the sought-after five stars. American NCAP is the North American equivalent.

ESP (electronic stability programme): Helps prevent skidding by reducing engine power or braking an individual wheel to regain control if slip is detected.

Exhaust brake: A basic type of engine brake consisting of a butterfly valve, fitted in the exhaust system, which closes off the exhaust pipe, building up pressure and producing a braking effect.

Fifth wheel: Device fixed to the top of a tractor chassis, which accepts a semi-trailer kingpin and secures it. It also allows the semi-trailer to swing from side to side and up and down relative to the tractor.

GPS: Global positioning system. The use of satellite-generated information to calculate a vehicle’s precise position, usually to within a few feet, almost anywhere. The essential reference point for satellite navigation systems.

HDC: Hill descent control. Land Rover’s system for automatically limiting the speed of a four-wheel drive vehicle on steep downhill terrain, by electronically controlling throttle and brakes. Just sit in your seat and nudge the steering wheel now and again!

Intercooler: A finned heat exchanger, rather like a small radiator, that uses the draught of ambient cooling air at speed to reduce the high temperature of intake air generated by air compression in the turbocharger. Improves engine efficiency, power, and economy by increasing the density of the intake air, allowing more fuel to be burned.

Kerb weight: The weight of a vehicle as it stands ready to go to work, complete with fuel, oil, water, spare tyre and all items of standard equipment, but excluding the driver/crew.

LCD: Liquid crystal display: Thin screen display technology that is far more compact than older types and is used for most in-car information systems, including SatNav and TV.

LED: Light-emitting diodes. Super-compact, semi-conductive, fast reacting light source, used for many things from alarm system indicators to high-intensity stoplights.

Litres per 100 km: This is the metric way of expressing fuel consumption. To convert the metric figure to miles per gallon, take 282,5 and divide by the figure for litres per 100 om. To convert mpg to litres per 100 km, divide 282,5 by the miles per gallon figure.

LKAS (lane-keeping assist system): Honda’s system identifies the boundaries of the vehicle’s lane by processing images from a camera mounted behind the windscreen. It then provided the optimum steering torque to help keep the vehicle in the centre of the lane. Volvo is developing a similar system called “driver alert” that will issue a warning if it senses the driver drifting off course and will be introduced on some models during 2007.

Multi-link Suspension: A sophisticated type of rear suspension system now becoming popular on many hatchbacks, like Golfs and Focuses, as well as on the more expensive cars like BMW. Maintains optimum tyre contact with the road, and gives a better roadholding and ride comfort compromise than the simpler (and cheaper) torsion beam trailing arm systems previously popular.

MPV: Multi-purpose vehicle, or more commonly, “people carrier”. Hailed locally as mom’s taxi.

NCSR: New car security rating. The truth about how easy your car is to break into, and to drive away, in figures.

OBD: On-board diagnostics. A major part of the ECU’s functions is measuring and recording all sorts of information on key engine and car systems. This can then be retrieved later by plugging into the car’s OBD “port” and using special instruments that recover and display any “fault codes” — allowing problems to be identified and rectified. This is not DIY stuff!

OCD: Occupant detection systems. This is a feature of advanced airbag protection systems.

OHC: Overhead camshaft. A camshaft is a revolving rod with offset lobes that open and close valves, allowing air into the combustion chamber and exhaust gases out. These shafts run across the top of the engine above (overhead) the valves.

Odometer: The odometer is built into the speedometer dial and shows the total distance travelled by the vehicle since its date of manufacture. Unlike the trip meter, the odomete cannot be reset to zero.

Oversteer means the car tends to turn too tightly into a corner - the tail slides to the outside of the bend. In extreme cases, the car goes sideways and then backwards. This can lead to the car hitting an obstacle sideways - where it has least strength and space for occupant protection. Oversteer isn't common in modern cars and there really isn't space here to describe the intricacies of controlling it. If you have a car that is a potential oversteerer, get yourself a book on driving or contact an advanced driving school.

PDC: Park distance control is a system of sensors that look for obstacles; audible or visible signs (or both) telling you you’re too close, becoming louder and more hysterical the closer you get!

Payload: The earning capacity of a vehicle. That is the weight of load it can carry legally, measured in kg or metric tonnes. Calculated by subtracting the kerb weight and the weight of driver and passengers from the GVW (gross vehicle weight).

Power: Power is the rate of doing work, and is used to measure the energy produced by an engine. The UK horsepower is defined as 550 lb.ft per second or 33,000 lb.ft per minute. Engineers use the metric system and measured in joules, time in seconds and power in watts. Kilowatts are hard to appreciate, and so are converted to horsepower, by dividing by a factor of 0.7457. As a matter of interest, the metric horsepower (PS), is slightly less than the British horsepower and this is arrived at by dividing the kW power by a factor of 0.7355. Nowadays, all vehicle manufacturers use the higher PS power output figure, but in the UK, it is often stated, wrongly, as hp or bhp.

PTO: Power take off. A means of taking power from the engine or more commonly from the transmission, in order to drive ancillary equipment, such as a crane, concrete mixer drum or pumps for unloading liquids and powders.

Quad cam: This means an engine has four camshafts, which are components of the valve train. The valve train opens and closes valves to allow fuel and air to enter the engine and compression and exhaust to be carried out of the engine.

Rear overhang: The distance between the rear axle centre line and rear of the body.

ROPS (Rollover protection system): This Volvo system incorporates a range of safety measures designed to minimise the chances of rollover accidents and offer extra protection in the event of the car turning over. It includes airbags that stay inflated longer to allow for repeated rollovers and a reinforced steel roof and pillars to prevent crumpling.

SatNav: Satellite navigation. GPS tells you where you are, SatNav tells you how to get to where you want to go, normally by using detailed mapping information stored on either CD or DVD, and giving either audible or visible instructions, or both.

Seatbelt pre-tensioners. Spring-loaded or possibly powered by a tiny explosive charge, and controlled by sensors, pre-tensioners instantaneously reel in any seatbelt slack in the event of an accident, to hold the occupant firmly back in his seat.

SIPS (Side impact protection system): Introduced by Volvo in 1991. Sips is designed to absorb the force of a side-impact collision. Its features include impact-protection bars in the side doors and front seats that will move slightly sideways away from the impact.

STC: Stability and traction control system. A method of combining electronic stability control and traction control. The traction control adjusts engine power and sometimes applies brake force to limit the amount the drive wheels can slip when you try to accelerate hard. Stability control senses steering wheel input and car body movement to detect the onset of sliding or spinning. Automatically applies braking effort to individual wheels and adjusts engine power to restore stability.

SUV: Usually a 4 x 4, sometimes a go-anywhere estate car, or nowadays perhaps a fancy bakkie.

Torque: This is the force that causes an object to rotate. In vehicles, it refers to the rotational force generated by the engine — in other words, the pulling power.

Torque steer: A phenomenon often encountered in high-powered FWD cars, where application of power leads to a change of vehicle direction, and a strong feedback through the steering wheel. Can lead to loss of grip on the front wheels, particularly when road grip is low in wet or slippery conditions.

Traction control: Usually part of a more complex safety system that prevents loss of vehicle control. Uses the feedback from ABS systems to compare speeds of driven wheel rotation and apply corrections when wheel spin is detected, usually by temporarily cutting the engine power.

TCS (Traction control system): Progressively applies the brakes to a driven wheel that is losing grip, may also retard the throttle to reduce power until it matches the available grip, Helps to maintain grip on loose, wet or changing surfaces.

Traction control: An increasingly common system for high-performance cars that senses the onset o of wheelspin under hard acceleration and gently backs off the power to regain traction.

Transponder key: The key talks electronically to the car, with coded signals from embedded chips. If key and car don’t recognise each other, then the car won’t open or start.

Turbodiesel (forced induction diesel engine). This is basically an air pump designed to use some of the fuel’s energy that would otherwise be wasted in the form of exhaust gases. These gases drive a turbine wheel that is coupled to a compressor wheel by means of a shaft. This compressor wheel is driven at gh speeds, forcing more air into the cylinders.

Turbo lag: A turbocharger cannot work at full power the instant you push the accelerator pedal. Instead, there is a lag of about half a second to one second (it varies from car to car and according to driving conditions) between the time you press the accelerator and the car fully accelerating. When acceleration does come "on boost", it's very strong and can take an inexperienced driver by surprise. Turbo lag can be frustrating and is the main reason turbos have lost favour in petrol-engined cars in recent years. If you're driving a turbocharged petrol-engined car for the first time, especially if the road is wet and slippery and the car has front-wheel drive, be cautious with the Accelerator until you get a feel for what the car is going to do. Turbo-diesel engines are much more forgiving in their characteristics than are turbo petrol engines. So also are the modern generation of light-power turbo petrol engines. The downside of low-lag engines is a lack of exciting power delivery.

Tyre pressure monitoring: Electronic system that uses information from the ABS system to detect small variations between rotational speed of all four wheels. Can detect under-inflated tyres and punctures, and therefore vital on cars using the new types of “run-flat” tyres, as on most new BMWs. Needs all four tyres to be of identical type and wear level to be accurate and not give false warnings.

Twin cam: This means an engine has two camshafts, which are components of the valve train. The valve train opens and closes valves to allow fuel and air to enter the engine and compression and exhaust to be carried out of the engine.

Understeer means the car tends to turn less into the corner than it should. In extreme cases, it won't turn into the corner at all; it simply ploughs straight ahead. For the average driver, understeer is easier to control than oversteer and is generally built into a modern car's steering as a safety measure. It doesn't start to show up until you are driving hard and can be reduced or negated by lifting your foot gently off the accelerator pedal.

Vehicle stability systems: Different manufacturers give it different names. Volkswagen call it ESP (electronic stabilisation programme). These systems add to simple traction control systems by using power reduction and selective braking on any of the four wheels, to gain stability when imminent loss of control, like a skid is detected. Hugely effective in wet and icy conditions.

VVT-I: Variable valve timing intelligence system. A system that adjusts the timing of the opening and closing of the intake and exhaust valves, as well as the degree of valve opening, in response to engine rpm. This helps stabilise engine output and idling. By varying the intake valve according to driving conditions, fuel consumption and emissions are minimised, while realising high power output for sparkling acceleration and driving performance.

Xenon/Bi-xenon: The 21^st century equivalent of halogen headlamps, the bright ones of their generation. High-intensity discharge Xenon produces more than twice as much light as a halogen system.