05 Feb 07
The suspension component that works with the shock absorbers to stop the car bouncing up and down on its springs. Traditionally hydraulic (using fluid reservoirs) but increasingly uses electronic systems. Adaptive or active dampers act to vary their force according to driving style; they reduce spring rate still further under sporty driving but allow more give when cruising.
Formerly the preserve of commercial vehicles, diesel (sometimes referred to as derv) is now the fuel of choice for a large proportion of cars of all sizes, but especially large family cars, MPVs and 4x4s. Diesel fuel contains more energy, litre for litre, than petrol and so diesel engines give more miles to the gallon. They also produce less carbon dioxide, meaning lower taxation. Traditionally diesels have produced more harmful emissions of particulates (unburnt soot) but modern fuel injection systems and now, in some vehicles, particulate filters, have helped reduce this. Diesel ultimately has the potential to be very green, as diesel fuel can be made from sustainable organic plant sources (biodiesel) as well as fossil oils.
Splits engine torque (pulling power) between the wheels to stop the outside one spinning when accelerating in corners. Also used to divide torque between the front and rear axles in four-wheel drive vehicles. Locking differentials can help overcome particularly tricky traction problems.
A fuel injection technology that involves injecting fuel directly into the cylinders to be mixed with incoming air, rather than the air being mixed with the fuel in a chamber prior to cylinder entry. The high-pressure fuel injectors are sited along a rail shared by several cylinders. More efficient, as a higher compression ratio can be set, with more precise control over combustion; emissions are also lowered, especially when the engine is cold.
Discs attached to the wheel hubs are gripped by a pair of callipers with pads either side, slowing or stopping wheel rotation. Standard on most cars, at least on the front wheels.
A GM system, also known as Active Fuel Management, that shuts down some of a large engine's cylinders - usually three out of six, or four out of eight - when the car is cruising, to save fuel. When the driver asks for acceleration the valves automatically open to give full engine capacity. Said to reduce fuel consumption in large cars by up to 10%.
Downward pressure exerted by the flow of air over and under the car's body. Big wings and front spoilers create a lot of it, thereby increasing high-speed stability and grip. [See also: Aerodynamics]
Deliberately inducing oversteer to make forward progress at a sideways angle. Useful in motorsport to get a car round a corner quickly, but has now developed into a sport in its own right, with drivers judged on style, speed and general flashiness.
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Refers to every part involved in the transfer of power to the wheels, namely the engine, clutch, gearbox, differential and driveshafts. Often used interchangeably with powertrain, although that term is sometimes intended to refer to just the engine and gearbox.
See Throttle-by-wire.
Headlights that stay on all the time. Once standard-fit in all Volvos and Saabs sold in the UK, as they're compulsory in Scandinavia. Plenty of evidence to suggest that they reduce accident rates, particularly on gloomy, grey days, so the EU is considering making them mandatory.
Direct Shift Gearbox, in Volkswagen-Audi language. A sporty semi-automatic gearbox with automatic double-clutch system and sequential-shift gearchanges as well as a fully auto mode using a torque converter. Audi has now started referring to it as S-Tronic, leaving the DSG label for other parts of the VW Group.
The Driver and Vehicle Licensing Agency, where you register changes of vehicle ownership. Sometimes referred to (by Arthur Daley types) as 'Swansea' after the location of its HQ. If 'the documents are in Swansea' don't put any money down until you've seen them.
