Automobile Basics V-Z
Value analysis (VA) Valve Device that opens and closes the combustion chamber of an internal-combustion engine to admit the fuel-air mixture or exhaust the gases.
Valve Float A high-rpm engine condition in which the valve lifters lose contact with the cam lobes because the valve springs are not strong enough to overcome the momentum of the various valvetrain components. The onset of valve float prevents higher-rpm operation. Extended periods of valve float will damage the valvetrain.
Valve Lifter Also called a "valve follower": the cylindrically shaped component that presses against the lobe of a camshaft and moves up and down as the cam lobe rotates. Most valve lifters have an oil-lubricated hardened face that slides on the cam lobe. So-called "roller lifters", however, have a small roller in contact with the cam lobe: thereby reducing the friction between the cam lobe and the lifter.
Valves (e.g. 24 valves) Signifies the total intake and exhaust valves in an engine. For example, a 24-valve V-6 would have 4 valves per cylinder 24/6=4. A 16-valve V-8 would have 2 valves per cylinder 16/8=2. More valves allow the engine to breathe better at high RPM and produce more power.
Valvetrain The collection of parts that make the valves operate. The valvetrain includes the camshaft(s) and all related drive components, the various parts that convert the camshaft's rotary motion into reciprocating motion at the valves, and the valves and their associated parts.
VEE Engine An engine with cylinders arranged in two rows at an angle to the common crankshaft. Has a "V" shape when viewed from the front.
(VIN) Number assigned to a automobile's by the manufacturer primarily for registration and identification purposes (consisting of numerals and letters).
VIS-A-VIS A four-seater in which two passengers faced the driver. Used around the turn of the century.
Viscous Coupling A particular kind of fluid coupling in which the input and output shafts mate with thin, alternately spaced discs in a cylindrical chamber. The chamber is filled with a viscous fluid that tends to cling to the discs, thereby resisting speed differences between the two shafts. Viscous couplings are used to limit the speed difference between the two outputs of a differential, or between the two axles of a car.
Voiture Legere A light car, especially a racing car falling between the heavy cars and the voiturette. Term seldom used to describe production cars. Not used after 1914.
Voiturette Early two-seater touring car. Name first used by Leon Bollee and then applied to any small car.
Waste gate A valve used to limit the boost developed in a turbocharger. A waste gate operates by allowing some of the engine's exhaust flow to bypass the turbocharger's turbine section under certain conditions.
Water Pump A pump that circulates coolant within the engine block and cylinder head. The water pump is driven by the engine crankshaft.
Wheel hop An undesirable suspension characteristic in which a wheel (or several) moves up and down so violently that it actually leaves the ground. Wheel hop can be caused by many problems, including excessive unsprung weight, insufficient shock damping, or poor torsional axle control.
Wheel Size (e.g. 15 X 7)Wheel size is defined by the diameter and width of the wheel. A 15 X 7 wheel has a 15-inch diameter and a 7-inch width.
Wheelbase The distance between the centers of the front and rear wheel axles as viewed from the side of the car.
Windsor Experiment Chrysler Canada, in partnership with government and educational institutions, has launched a number of initiatives collectively referred to as the Windsor Experiment. The Windsor Experiment conducts studies to benchmark "best practice" training and education in Europe, and applied the results in various skills development programs.
Wishbone Suspension (Double Wishbone Suspension) An independent suspension that uses curved members (wishbones) to control suspension travel. A wishbone suspension offers good axle control, and limits undesirable suspension.
Yaw The rotation about a vertical axis that passes through the automobile's center of gravity.
Zero-offset steering A steering system whose geometry has a scrub radius of zero. This configuration minimizes the steering effects produced during acceleration (with front drive) or braking on varying traction surfaces.
|
