Any device that transfers power through a fluid between its inputs and outputs. A fluid coupling basically consists of two fans in a sealed, oil-filled housing. The input fan churns the oil, and the churning oil in turn twirls the output fan. Such a coupling allows some speed difference between its input and output shafts.

Flushing is a means of entirely replacing the fluid in a given system. For instance, when a technician flushes a cooling system, all the old coolant is removed and completely replaced with new.

A metal plate bolted to the crankshaft; it usually includes a gear that's engaged by the starter motor. Around the outer perimeter is affixed the ring gear. The starter drive engages the ring gear, turning the flywheel, which rotates the crankshaft, imparting the initial starting motion to the engine.

The amount of energy or work needed to raise an item weighing one pound, a distance of one foot.

Prediction of future production or sales in the automotive industry.

A process that transforms solid metal into shapes of varying cross-sectional material thickness, often involving heating.

A valvetrain with a total of four valves in the combustion chamber, typically two intakes and two exhausts. Compared to the more common two-valve-per-cylinder designs, a four-valve layout offers improved breathing and allows the spark plug to be located closer to center of the combustion chamber.

On a vehicle equipped with Four-Wheel Anti-Lock Brakes, all four wheels are equipped with speed sensors. When these sensors determine that the wheels are decelerating so rapidly that lockup may occur, the Electro-Hydraulic Control Unit (EHCU) is activated. The EHCU then modulates the brake pressure in the appropriate brake lines by means of the solenoid-operated valves. This is intended to prevent wheel lockup and help the vehicle maintain directional stability during potentially hazardous braking situations.

In a Four Wheel Drive system, a secondary transmission assembly, called a transfer case, is driven from the main transmission. The transfer case distributes power to both axles to drive all four wheels. It is the heart of the Four-Wheel Drive system. Four-Wheel Drive can be full-time, in which power is delivered to both axles at all times or part-time, where the driver selects two or four wheel drive. Four wheel drive is often combined with independent suspension systems and off-road type tires to enhance driveability on rough, off-road terrain, or on-road driveability in unfavorable driving conditions. 4WD provides superior traction compared with front or rear-wheel drive.

A type of suspension in which all wheels are mounted to separate suspension members with no rigid axle connecting them. Therefore a disturbance affecting one wheel has no effect on the opposite wheel. Four wheel independent suspension reduces the un-sprung weight, improves ride and handling over rough surfaces and permits room for a larger trunk.

A mechanism that allows the rear wheels to steer. The steering angle is usually limited to 2-3 degrees. 4WS actively steers the rear wheels as well as the fronts to improve handling and maneuverability allowing more stable cornering.

An internal-combustion engine that requires two revolutions per cylinder or four piston strokes to achieve a power stroke internal stroke, compression stroke, power stroke, exhaust stroke. More efficient than the two-stroke-cycle engine. Also called Otto cycle.

A somewhat imprecise term that describes a cornering situation in which all four tires are operating at large slip angles.

A bridge-like, structural base of a car that supports and positions the body and major mechanical items.

Establishment that has the right to exercise the powers of a corporation.

A drive system where the engine and transaxle components apply the driving force to the front wheels rather than the rear wheels. FWD allows better use of interior space than RWD because all drivetrain components are concentrated in the front of the car. Enhanced cargo area. Excellent drive traction; particularly on wet or slippery surfaces, since the drive is through the front wheels, which carry a heavier load.

On internal-combustion engines, a system that injects a precisely measured amount of fuel into the cylinder at exactly the right moment. Dispenses with the carburetor and increases engine efficiency. Fuel injection provides better metering of fuel and air than carburetors. This results in more power, improved fuel economy, and lower emissions. The simplest systems use single or dual injectors in a central chamber to supply all cylinders. More sophisticated systems use an injector at each cylinder to precisely meter fuel.Any system that meters fuel to an engine by measuring its needs and then regulating the fuel flow, by electronic or mechanical means, through a pump and injectors. Throttle-body injection locates the injector(s) centrally in the throttle-body housing, while port injection allocates at least one injector for each cylinder near its intake port.

A computer-controlled method of delivering fuel under pressure. The computer monitors signals from coolant temperatures, manifold vacuum, exhaust oxygen sensor, and engine cranking sensor. It 'tells' the injectors to release and adjust the fuel to yield an air/fuel mixture assuring engine operation well matched with emission requirements, optimum fuel economy and overall vehicle performance.

Electrically controlled valve that delivers a precise amount of pressurized fuel into each combustion chamber. Most cars have them instead of a carburetor these days.

A device that maintains proper fuel pressure under all driving conditions and engine loads.