Automotive Glossary
Automotive Glossary
Browse the glossary using this index
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I.F.SIndependent Front Suspension. Also inertia fuel shut off switch used to switch off an electrical fuel pump or diesel fuel pump solenoid when the vehicle is involved in an accident." | |
I.R.SIndependent Rear Suspension." | |
IA ISAIdle adjust. Idle speed adjust. | |
IACIdle Air Control | |
IATIntake air temperature sensor used in electronic fuel injection as a correction factor for the quantity of fuel to be delivered. | |
IATSIntake Air Temperature Sensor | |
ICIntegrated Circuit | |
ICEIn Car Entertainment system. | |
ICMIgnition Control Module. | |
ICSIdle Control Solenoid | |
ICTInformation and Communication Technology. | |
IDInside Diameter | |
IDIIndirect injection of diesel fuel into a pre-combustion or swirl chamber in the cylinder head. | |
IdleTerm used to describe an engine running at a speed when the throttle has not been depressed. Also used to describe a lazy technician... | |
Idle Air Control (IAC)Idle air control. An air valve on fuel injection systems to increase the air flow and idle speed of a cold engine and during warm up. | |
Idle Control ComponentsParts that are designed to keep the engine idle speed at a set level. | |
Idle MixtureThe fuel strength or air/fuel ratio. | |
Idle SpeedRotational speed of an engine on no-load and minimum throttle setting. Also tick over and curb idle. | |
Idler ArmA steering arm parallel to the Pitman arm (drop arm) and connected to it by a centre track rod. | |
IdlingDescribes an engine running at idle speed (usually 700 to 800 rev/min). | |
IECInternational electrotechnical commission | |
IFIIndirect Fuel Injection | |
IGBTThe insulated gate bipolar transistor or IGBT is a three-terminal power semiconductor device, noted for high efficiency and fast switching. | |
IGNIgnition | |
IgniterThe part of an air bag unit that sets the inflation process in to action. | |
Ignition - IGNStarting of combustion. Setting fire to a flammable substance. In a petrol engine the spark jumping the spark plug electrodes that starts the combustion process. | |
Ignition AdvanceThe automatic bringing forward of the ignition spark in relation to the engine speed. | |
Ignition circuitThe system used to connect components involved in producing a high voltage at the spark plugs. | |
Ignition CoilAn electrical transformer that increases the battery voltage to a high tension capable of arcing across the gap of spark plug electrodes. | |
Ignition Coil - IGCAn electrical transformer that increases the battery voltage to a high tension capable of arcing across the gap of spark plug electrodes. | |
Ignition DistributorA component in the ignition system that houses the primary circuit switching device and the secondary circuit distribution components. | |
Ignition LagA short delay after injection before the fuel ignites. | |
Ignition ModuleThe electronic unit that switches the ignition coil on and off in response to a signal from a pulse generator. | |
Ignition SwitchThe engine ignition and vehicle electrical circuits control switch used by the driver to start and stop the engine. | |
Ignition TimingThe static and dynamic settings of the ignition distributor or in the engine control module (ECM) that control the ignition coil secondary circuit output and spark for starting the combustion process in the engine. | |
IlluminationLighting up, making bright. | |
IMAIntegrated Motor Assist is Honda's term for their hybrid propulsion system. This includes the electric motor/generator, 144v battery pack, controlling electronics and the wiring that connects them all together. ISG or ISA is used by some manufacturers, Integrated Starter Generator or Alternator. | |
ImmediatelyTaking place without delay. | |
Immiscible (non-miscible)Incapable of mixing in or blending with other components. | |
ImmobiliserUsually part of an alarm system. It cuts off the ignition or fuel to prevent a vehicle from being started and stolen. | |
Impact SwitchA switch that operates when the car impacts something. Used as a safety device to cut off a fuel pump. | |
Impact ToolsPower tools that use a high frequency hammering action for the removal and installation of nuts and bolts, for drilling and chiselling. Impact tools should only be used with sockets, drills and chisels made for that purpose. The use of normal hand tools form impact is hazardous as these may shatter in use. | |
ImpellerVaned disc that creates flow by centrifugal force (water pump). In a torque converter it is driven from the engine to force liquid onto the turbine. | |
ImperialOld British standard of measurement using yards, feet and inches. | |
Imperial MeasurementDefined by three measures - the gallon, the yard and the pound. | |
In-line EngineA engine fitted along the axis of a motor vehicle. | |
Inboard BrakesBrake units fitted on the final drive casing and output shafts rather than on the wheel hub and carrier. | |
IncandescenceLight given off by a high temperature object. Usually describes a bulb filament. | |
Included AngleCamber and steering swivel (king pin) inclinations (angles) added together. | |
Incoming Telephone CallTo receive a telephone call. | |
Independent SuspensionSuspension fitted to each wheel." | |
Indirect InjectionDiesel engine design where fuel is injected into a pre-combustion chamber fitted inside the cylinder head. | |
Induced VoltageNaturally occurring voltage in a conductor when subjected a magnetic flux. | |
InductanceProperty of a coil such that an increase in current causes an increase in magnetism, which in turn tends to prevent the original increase in current. See also Lens's law. | |
Induction1. The drawing in of a gas or fluid. 2. Process of causing an electrical potential in a conductor due to relative movement of a magnetic field. | |
Induction PeriodAn allotted amount of time upon mixing of components for compatibilization. The process is common among the use of epoxy/polyamide coatings. | |
Induction StrokeFirst stroke of four stroke cycle when air and fuel enter the engine as the piston moves down the cylinder. Also known as the intake stroke. | |
Inductive CoilAll coils possess inductance. This is the property that resists changes in current flow. | |
Inductive GeneratorA magnetic/electrical pulse generator used as a sensor in electronic control systems. It uses an iron core and electrical winding to induce an electrical current when passed by a toothed wheel or rotor. Also known as a magnetic pulse generator. | |
Inductive SensorA coil and magnet used in conjunction with a trigger wheel. It produces a sine wave output with a frequency proportional to speed. | |
Industrial FalloutChemical compounds present in the air which are deposited on the horizontal surfaces of vehicles and which may damage the finish. | |
Inert GasA non-reactive gas element. | |
InertiaThe force that holds a body stationary or in uniform motion. | |
Inertia ReelType of seat belt that holds spare webbing on a reel and locks the reel on impact. This is performed by a swinging weighted ball and lever that locks the belt reel ratchet wheel with a pawl. | |
Inertia SwitchA switch that operates by the inertia (need to stay at a constant speed or state of rest) of a mass. Usually used to cut off supply to a fuel pump in case of a crash. | |
InflationThe general increase in the price of goods and services. | |
InfraredLight energy that produces radiated heat, used for speeding up the curing of paint, filler, etc. | |
Infrared LightThat portion of the spectrum responsible for most of the heating effects of the sun's light. Not visible to the human eye. | |
Infrared LightingInfrared light is outside the visible spectrum. When used for lighting, a special detector is also needed. | |
Infrared SensorA sensor that is sensitive and produces a signal in response to infrared light. | |
IngestionTake in by swallowing or absorbing. | |
InhalationBreathing in. | |
InhibitTo hinder or to restrain progress. | |
InhibitorA chemical added to retard or prevent a particular reaction. | |
Inhibitor SwitchA simple switch that prevents the operation of a circuit. A good example is the switch in an automatic transmission gearbox that prevents operation of the starter motor when drive or reverse is engaged. | |
InhibitorsA chemical that restricts or reduces the chemical reactions. In a cooling system an inhibitor is added to prevent corrosion of the engine from the ethylene glycol content of the antifreeze. | |
Initial diagnostic assessmentThis is carried out to find a candidates strengths and weaknesses, current levels of attainment and potential. | |
InitiatorA chemical added to help start a chemical reaction such as polymerization or curing. | |
INJInjector valve. | |
InjectionOf fuel by pressure into inlet manifolds (petrol) or combustion chamber (diesel). | |
Injection LagA short time delay between actuation and actual operation of an injector. | |
Injection TimingPoint within the four-stroke cycle when injection occurs. Similar to ignition timing on petrol engines. | |
InjectorControl valve and nozzle used to inject and atomise fuel. | |
Injector lagA short time delay between actuation and actual operation of an injector. | |
Injector NozzleThe tip of a fuel injector, which is drilled to produce a particular spray pattern. | |
Injector Pulse WidthWhen viewed on an oscilloscope, the horizontal width of the trace. This represents the open time of the injector. | |
Injector PumpFuel pump that produces the timed high pressure pulses for the injection and timing of fuel delivery on a diesel engine. | |
Inlet ManifoldDucting that connects the carburettor/fuel injection components to the inlet ports in the cylinder head. | |
Inlet PortsThe way in to the engine for fuel/air mixture. | |
Inlet ValveValve in the inlet port that allows air or air/fuel mixture into an engine. | |
Inline PumpType of diesel fuel injection pump with the pump elements in line. | |
Inner RacesThe inside rings of ball or roller bearings. | |
Inner TubeThe separate sealed air tube on a tyre that is required with certain types of tyre and wheel rim. | |
Inner WingMetal panel structure under the bonnet forming part of the wing. | |
InputPower or data that goes into a mechanical unit or electronic control module. | |
Input DeviceA device that allows you to put information into the computer. Egg, keyboard, mouse. | |
Input ShaftShaft that takes drive from the engine into the gearbox. | |
Insert (Valve Seat)A steel insert fitted in aluminium and some iron cylinder heads to form a durable seating for the inlet and exhaust valves. | |
InshotA feature of air brakes designed to give an initial quick application to make up for the time it takes for air pressure change. | |
Instrument LightsIllumination for instruments such as the speedometer. | |
Instrument PanelThe panel in a vehicle fascia that holds the instruments and warning lights. Also dash panel and dashboard. | |
Insulated CircuitA vehicle wiring system that does not use the body and chassis as a ground to form a return electrical circuit to the battery and alternator. A separate insulated set of cables connects all components to complete the circuits. Used in vehicles where there is a high fire risk. (Fuel tankers). | |
Insulation resistanceThe resistance to current flow of the insulating materials between circuits and contacts. | |
InsulatorRestricts the flow of electricity or heat through the material. | |
Intake ManifoldSee inlet manifold. | |
Intake StrokeAlternative term for the induction stroke. First stroke of four stroke cycle when air and fuel enter the engine as the piston moves down the cylinder. | |
Integral Body ConstructionModern light vehicle body and chassis construction method which has no separate chassis. The strength is built in by the use of stressed and reinforced panels. | |
IntegrateTo incorporate something into something else or to unite into a whole. | |
Integrated Circuit (IC)An electronic device consisting of transistors, diodes and other components in a single unit and usually having a specific function. | |
IntegrityData corruption refers to errors in computer data that occur during transmission, retrieval, or processing, introducing unintended changes to the original data. Computer storage and transmission systems use a number of measures to provide data integrity, or in other words the lack of errors. | |
Intelligent deviceA component that has some ability to monitor itself and react to changes. | |
IntensifierA device which converts low pressure fluid power into higher pressure fluid power (used by some injection systems) | |
Inter-Quartile MeanThe average of the values in the inter-quartile range. | |
Inter-Quartile RangeThe range of numbers with the upper and lower quartiles removed. | |
InteractiveTwo-way communication. | |
IntercoolerAn air to air radiator type heat exchanger fitted after a turbocharger in the air intake ducting to cool the intake air before it enters the engine. | |
Interference FitThe relationship between the dimensions of two components where one fits inside the other. In this instance the fit is one where the inner dimension of the outer component is less than the outer dimension of the inner component. | |
Interior LightsLights inside a vehicle for illumination purposes. | |
Interleaf FrictionFriction between spring leaves that produces a damping effect. | |
InterlockPart of a manual gearbox selector mechanism that prevents the engagement of two gears at the same time. | |
Intermediate GearAny gear in a transmission gearbox other than top and bottom or reverse. | |
Intermediate ShaftA shaft between the input and output shafts, usually as part of a gearbox. | |
Internal CombustionEngine where fuel is burnt inside cylinders. | |
Internal CustomerOne inside of an organisation. | |
Internal DampingA feature of some suspension components where friction tends to reduce oscillations. | |
Internal ResistanceDescribes the resistance of a component that is the combination of all its internal parts. Even a battery has some resistance inside it. | |
Internal SplinesSplines (teeth) inside a shaft or tube. | |
Internal TaperA hole that narrows. | |
Internal verificationThe process whereby a centre ensures it operates consistently and to national standards in interpreting and assessing the key skills. | |
Internal WindingsWindings inside a component. | |
InternetA worldwide network of computers that allows us to view the World Wide Web. | |
InterpretTo understand and be able to explain something. | |
IntimidatingTo make somebody feel uncomfortable, timid or even fearful. | |
IonAn atom with positive or negative charge due to gain or loss of an electron. | |
IPUIntegrated Power Unit. | |
IridescentsAll colours that contain aluminium, mica, or other particles that impart a metallic appearance to the colour. | |
Irradiation TreatmentA process where something is acted upon by radiation from a radioactive substance - it is used to make some foodstuffs last longer - but is a contentious issue! | |
ISInertia Switch. | |
ISCIdle Speed Control. This term is usually used when a stepper motor or solenoid is used for idle speed increases during engine warm-up and when ancillary systems are in use. | |
ISOInternational Standards Organization | |
Iso-octaneA fuel used in research tests as a comparison when determining the octane rating of fuels. Octane value of 100. | |
IsocyanateA chemical found in the hardening agent used with acrylic urethane and other two component reaction type paints. The introduction of Isocyanates in hardeners led to the requirement for air-fed respirators in the vehicle painting industry | |
ITInformation Technology | |
ITCSIgnition Timing Control System | |
ITSIdle Tracking Switch | |