Glossaries

Friday, 19 April 2024, 1:13 PM

Site: IMI eLearning

Course: IMI eLearning (IMI eLearning)

Glossary: Automotive Glossary

F

Fahrenheit

F-CAN

Fast CAN

F.W.D.

Front wheel drive."

Face-tone

The colour perceived by the brain when a painted surface is viewed from an angle of 90° - that being the angle at which the greatest amount of light reflection will occur

Factory-applied Paint

Paint applied to a vehicle at the factory of the original equipment manufacturer (OEM). Factory-applied paint is normally cured by baking.

Fading

The gradual loss of colour or gloss of a paint film due to a chemical or physical change, usually due to natural ageing or exposure to harmful environmental conditions

Fail Safe

A device or feature that prevents total failure in the event of a fault occurring.

Fallback

The process by which testing may continue when the computerised system is not available at a VTS, for example, following the breakdown of the VTS device.

Fallback Review

The process by which test data recorded while testing under Fallback is subsequently confirmed on the MOT computer database.

Fan (fan width)

The spray pattern of paint as it is emitted from a spray gun. Most spray guns have adjustments that can alter the fan width from a small round pattern to an elongated elliptical pattern.

Fan Cowl

A protective shield around a fan.

Farad

The unit of capacitance.

Fascia Panel

The panel inside the vehicle below the front windscreen. It carries the instruments, heater ducts and accessories.

Fast Charge

Rapid charge for a battery. 5 times the Ah capacity for about an hour is the recommended maximum.

Fast Idle

The cold engine running speed achieved by a stepped cam on the throttle linkage or by an air bleed valve.

Fatigue

Failure in a material due to excessive and repeated loading usually of an intermittent nature.

Fault

The cause of a problem that results in symptoms

Fault Code

A code generated in and output from an ECU. Used for diagnostics.

Fault-tolerant

In engineering, fault-tolerant design, also known as fail-safe design, is a design that enables a system to continue operation, possibly at a reduced level, rather than failing completely, when some part of the system fails.

FBC

Feedback Carburettor System

FBCA

Feedback Carburettor Actuator

FCS

Fuel Control Solenoid

FDC

Fuel Deceleration Valve

Feather-edge Splitting

Fractures or cracks along the feather-edge which occur during drying or shortly after the topcoat has been applied over primer-surfacer. This problem occurs due to poor preparation, use of excessively fast solvents in primer, improper flash-off time and/or very aggressive solvents in topcoat.

Feather-edging

Tapering a paint edge from substrate to topcoat or between layers of paint material by sanding. If feather-edging has been carried out efficiently, it should not be possible to feel the edges with the finger tips.

Feathering

Term used to describe the way a tyre wears when the tracking is set incorrectly. The tread scuffs up like feathers.

Feed (leather)

The process of treating leather with soaps and creams to improves its lifespan and appearance.

Feed Cable

The main supply wire to a component.

Feedback

A feature used in electronic control systems to monitor performance by the use of a sensor downstream of an actuator. An example is an exhaust oxygen sensor monitoring the fuel injection quantities.

Feedback Resistor

A variable resistor used to indicate position of a moving component.

Feeler Gauge

Set of accurate blades used to set or measure small gaps (valve clearances for example).

Ferrites

These are chemical compounds, ceramic with iron oxide as their main components. Many of them are magnetic materials and they are used to make permanent magnets, ferrite cores for transformers, and in various other high tech applications.

Ferrous

Describes any metal composed of or containing iron, such as low-carbon steel, stainless steel, etc.

FI

Fuel Injection

Fibreglass

Very fine fibres of glass that are supplied as reels of single fibres or spun together as woven matting. It is used in the manufacture of glass-reinforced vehicle bodies, panels, and for component parts and repairs on automobile bodies.

Field (Magnetic)

A magnetic flux about a permanent magnet or live electrical conductor.

Field Circuit

An electrical control circuit for the field coils used to regulate the output from a generator.

Field Coil

An electrical winding round a magnet pole shoe that is used to create a magnetic field when an electrical current flows through the windings. The direction of current flow determines the polarity of the magnetic pole. Used in generators and electrical motors.

Field Coil (Winding)

Filament (Bulb)

The tungsten element in a bulb that glows to produce light.

Filaments

The tungsten elements in a bulb that glow to produce light.

Filiform Corrosion (Spidering)

A paint defect caused by moisture ingress between the substrate and the paint film, e.g. via an untreated stone chip, that continues to travel in 'spidery' threads.

Filler

Commonly, a heavily pigmented sprayed foundation paint used to fill imperfections and pores in a substrate. To avoid confusion with 'Body Filler', should be referred to as 'Primer-Filler' or 'High-Build Filler'

Filler Neck

The connection into the fuel tank for refuelling.

Fillet Radius

A machined curve between two faces of a component. An example is the curve between a crankshaft web and journal.

Film

A very thin continuous sheet of material. Paint forms a film on the surface to which it is applied.

Film Thickness

The thickness or depth of a dry paint film is important. Thin films may appear to be the wrong colour due to their lower opacity, and may also have durability issues. Over-thick films are likely to crack in use. The thickness of paint films on iron or steel surfaces is easily determined with a magnetic gauge.

Film Thickness Gauge

A device used to measure the coating thickness on a substrate. Magnetic devices are used to measure the thickness of ferrous metals; whereas electronic devices are used on non-ferrous substrates.

Filter

A fine mesh or paper screen used to remove dirt and other contaminants from a liquid or gas (air).

Final Drive

The gearing immediately before the driven wheels. It provides a split to each driven wheel with a final gear reduction for the transmission. Can also be used to turn the drive through 90° with the use of bevel gears.

Finesse coat

See 'Drop coat'

Finish

A protective coating of paint; usually referring to the final appearance of the painted surface. Also, to apply a paint or paint system.

Finishing Film

A fine graded abrasive disc for sanding top coat automotive paints before repainting or compounding.

Firewall

Substantial structural panel of vehicle body in front of passenger compartment. Also known as a bulkhead.

Firing Order

The sequence for ignition of individual cylinders in an engine.

Fish Eyes

A surface depression or crater in the wet paint film. Fish Eyes are caused by repulsion of the wet paint by a surface contaminant such as oil or silicone. The depression may or may not reveal the surface under the paint, depending on its depth or severity.

Fish-Eye Eliminator

Additive used in paint to prevent the occurrence of fish eyes (craters/silicones) in a freshly painted surface - usually caused by the presence of contaminants such as wax polish.

Fixed Caliper

A disc brake caliper in which the two halves and pistons are made as a single unit attached to the axle assembly.

Fixed Choke Carburettor

A carburettor with a fixed diameter venturi (choke tube).

Fixed Venturi

A narrowed section in a carburettor - the size of which remains fixed.

Flake

A decorative pigment consisting of flat particles. Usually mica, aluminium or other bright metals, providing special colour effects to the final paint finish.

Flake Orientation

The appearance of the metallic particles in a paint film during and after drying or curing. Selection of the correct flakes in the colour mixing formula and proper application will lead to good flake orientation and thus to good colour match and appearance.

Flaking

A serious paint defect characterised by the paint film lifting and eventually falling off of the substrate.

Flame Plug

Cold start device fitted in the inlet manifold on some direct injection diesel engines.

Flame Trap

Incorporated into the air cleaner unit to prevent the spread of fire caused by fuel igniting in the carburettor if blow back occurs.

Flange

Flat face to flat face butted fitting. Method used to secure exhaust system.

Flange Bolts

Bolts that secure a flat face to flat face butted fitting.

Flange Fitting

Flat face to flat face butted fitting. Method used to secure exhaust system.

Flare Joint

A method of connecting pipes, particularly steel brake pipes, where the end of the pipe is deformed to give a concave or convex flare which is secured with a union nut.

Flash Rusting

A surface rust occurring from improper cleaning or exposing bare metal to the air and moisture for too long of a period.

Flash-off

The first stage of paint drying where some of the solvent content evaporates. This typically dulls the surface from an exceedingly high gloss to a normal gloss or flat appearance.

Flash-off Time

The time between paint application and consecutive coats.

Flashpoint

The temperature at which a liquid will give off a flammable vapour that would ignite when a spark is struck.

Flat (finish)

Lacking in gloss. (See Matting agent)

Flat Seat Valve

A valve that operates by one part operating against a flat component to control flow.

Flat Spot

A temporary drop in power that occurs at the point of initial acceleration when the throttle plate is opened. Occurs as a result of a rise in venturi pressure (drop in vacuum) and a resultant loss of fuel supply into the venturi. Remedied by the addition of an accelerator pump.

Flat-seat Valve

A valve that operates by one part operating against a flat component to control flow.

Flatting

The rubbing down of repaired or pre-painted surfaces with abrasives to achieve the desired shape, prepare the surface for painting or prior to polishing.

Flex Plate

The mounting plate for a torque converter where it is attached to the crankshaft. Fits in place of the flywheel.

Flexible

Being able to accept change.

Flexible Additive

A substance added to paint to improve its performance characteristics, such as impact resistance, flexibility, and elasticity when applied to plastic or flexible substrates.

Flexible Coupling

A rubber or fabric reinforced rubber coupling that is used to join two shafts. Usually incorporates two forks that act as a safety device in the event of failure of the rubber component.

Flexing

Another word for bending.

Flip

The change in value, hue, and chroma of a metallic or pearl car finish when it is viewed from different angles.

Flip-tone

The colour perceived by the brain when a painted surface is viewed from an acute angle (i.e. less than 90°). - the more acute the angle, the less amount of light reflection occurs, giving an impression that the colour is darker

Flitch

A longitudinal cut

Flitch Panel

Structural panel of vehicle body on sides of engine.

Float

A buoyant component used to indicate or control fluid levels. In a carburettor used with a needle valve to control the petrol level in the float chamber.

Float Chamber

Part of carburettor holding petrol at a controlled level.

Floating

The tendency of pigment particles in a wet paint film to separate from one another and concentrate in particular areas, resulting in a 'patchy' finish

Floating Caliper

A disc brake caliper that has a fixed component attached to the axle assembly and a single piston and caliper that is 'floating' by sliding or pivoting on the fixed component.

Flocculation

Clumping together of pigment particles within the wet paint.

Flooding

The tendency of pigment particles to rise to the surface during curing and produce a colour variation at the surface and a lack of uniformity in the colour appearance through the film.

Floppy Disk

A portable disk that stores 1.44Mb of information.

Flow

The levelling characteristics of a wet paint film.

Flow Meter

A sensor that determines flow of a fluid or gas.

FLS

Fluid Level Sensor

Fluid Coupling

A drive coupling that uses a fluid to transmit drive. Also sometimes a viscous coupling.

Fluid Flywheel

A drive coupling that uses a fluid to transmit drive.

Fluid Needle

The part of a spray gun that opens and closes the fluid passage in the fluid tip.

Fluid Pump

A pump for moving or pressurising a fluid.

Fluid Tip

Part of a spray gun that meters and directs the fluid stream.

Flyweights

Weights that act on pivots and move outwards due to centrifugal force.

Flywheel

(1) Component of the clutch. (2) Massive wheel or disc attached, for example, to the crankshaft of an engine, to store energy of rotation and smooth the output from the irregular firing of the cylinders. In many automotive engines, the flywheel incorporates the ring-gear and acts as one friction face of the clutch. (3) Maintains the momentum of the engine.

FO

Fuel Octane Adjustment.

Foaming

A term used to describe the aeration of an oil.

Focal Length

The distance between the focal point and the reflector.

Focal Point

The point within a reflector from where a light source produces parallel beams.

Focussed

To the point.

Follower (Cam)

The component in contact with the cam on a camshaft.

Foot Pound

Old unit of torque. Also pounds/feet. Torque is now given in the SI units of Newton metres (Nm).

Footprint

When applied to tyres describes the area and shape of the part of the tyre in contact with the road.

Force

Exerted to overcome a load.

Force Ratio

The comparison of the force applied to the force produced via some kind of machine or system.

Force-Dry

A method of accelerating the drying of paint with the aid of heat.

Forging

A component forming process applied to hot metal with a hammer or die either by hand or machine. Also hot stamping.

Fork

Part of the door latch mechanism, clutch or gearbox. Fits around another component to hold or move that component.

Fossil fuel

This relates to any fuel made from hydrocarbon deposits such as coal, petroleum, natural gas and, to some extent, peat; these fuels are irreplaceable, and their burning generates the greenhouse gas carbon dioxide.

Four Stroke Cycle

The conventional operating principle for the modern internal combustion engine consisting of the induction, compression, combustion/power and exhaust strokes.

Four Wheel Drive (4WD) (4x4)

Transmission system that uses all four wheels of a vehicle to provide a drive. This term is usually used on vehicles with selectable four wheel drive. The term AWD for all wheel drive is used for vehicles with permanent four wheel drive.

Four Wheel Steering (4WS)

A steering system that applies turning movement to front and rear wheels. The rear wheel steer is initially opposite to the front wheels, neutral and then with the front wheels. This provides steering characteristics that aid manoeuvrability.

Four Wheel Steering 4WS

FP

Fuel Pump.

FPR

Fuel Pump Relay.

Fractions

A number of parts out of another number of parts.

Franchise

This is an authorization to sell a company's goods or services in a particular place.

Free Electrons

The electrons in the valency shell of an atom that can link with and move on from other atoms. A material with free electron flow makes a good electrical or heat conductor.

Free Play

The amount of free movement in or between components that is not transmitted to the next component in the sequence. May also be referred to as 'backlash' in some applications such as when applied to gears.

Free Travel

The free play in a clutch linkage before it operates the clutch mechanism.

Freeplay

Freewheeling

Overrun of a one way clutch. Vehicle movement when the transmission is not engaged to the engine.

Frequency

The number of oscillations per unit of time. Examples are a sound wave or alternating electrical current. The unit for frequency is the Hertz, which equals one oscillation per second.

Friction

Resistance a body encounters in moving over another.

Friction Disc

Term used to refer to a clutch drive plate.

Friction Discs

Component of the clutch. The centre plate that is gripped between the flywheel and pressure plate to transmit a drive to the gearbox input shaft.

Friction Material

A material with consistent performance characteristics used to provide a rubbing surface for brake and clutch components.

Friction Plate

Component of the clutch. The centre plate that is gripped between the flywheel and pressure plate to transmit a drive to the gearbox input shaft.

Front-end Solvent

A fast-evaporating solvent that leaves the paint very soon after application.

FT

Fuel Temperature Sensor.

ft.lb

Foot Pound"

Fuel Distributor

The component in a mechanical injection system that controls and distributes the fuel.

Fuel Efficiency

Performance of engine/vehicle. Rate of fuel usage.

Fuel Filter

A filter to remove contamination from fuel.

Fuel Gauge Sender

Sensor, usually a variable resistor, which supplies information on fuel quantity in the tank.

Fuel Injection

The injection of fuel under pressure into the intake air stream of petrol engines by the use of electrical solenoid valves in place of a carburettor.

Fuel Line

The pipes and hoses that connect the fuel system components.

Fuel Pressure Regulator

In a fuel system the component that keeps the pressure across injectors constant. It consists of a valve, diaphragm and spring.

Fuel Rail

A tube or pipe used to supply fuel to electrical injectors. The quantity of fuel in the rail is relatively large so that the pressure remains constant when the injectors operate.

Fulcrum

A pivot for a lever. Usually a supporting point or shaft.

Fulcrum Ring

A ring on which clutch release fingers pivot.

Full Flow Lubrication

An engine lubrication system where all of the oil flows through the oil filter before entering the engine oil galleries.

Full Load

Describes the engine condition when it is working as hard as it is able - for acceleration for example.

Full Load Enrichment

A device in a carburettor that provides additional fuel during full throttle and heavy load conditions.

Full Wave Rectification

Alternating current converted to direct current by reverse flow of the negative bias so that it is added to the forward bias electrical flow. Modern rectifiers using a diode bridge achieve full wave rectification.

Fully Floating Axle

An axle hub arrangement that carries the load on two bearings and therefore does not apply a shear or bending force on the axle shaft.

Fuse

A safety device in an electrical circuit that will burn and melt to break the circuit when an excess current is applied.

Fuse Box

A central termination block in a vehicle electrical system that carries the fuses.

Fuse Rating

The rated value of a fuse before failure due to an excess current load. The rating can be either a constant or a surge value and is given in amps. Fuses are usually colour coded and marked for the fuse rating.

Fuzzy Logic

A digital control system that makes 'educated' guesses.

FWD

Front-Wheel Drive