Karnataka SSLC Automobile - NSQF (KSEAB) key terms

A wrench that measures and limits the turning force applied to a fastener so bolts are tightened to a specified value without being overstretched or stripped.

The exact tightening force, usually given in newton-metres, that a manufacturer states for a particular bolt or nut, often differing between dry and lubricated threads.

A set of thin metal blades of known thickness used to measure small gaps such as valve clearance, spark plug gap or contact breaker point gap.

A measuring tool with a sliding jaw and a secondary scale that reads outside, inside and depth dimensions to a precision of about 0.02 mm.

A precision measuring instrument with a calibrated screw that measures thickness or diameter, commonly used to check piston, crankshaft journal and valve stem wear.

The clothing and gear worn to reduce injury risk in the workshop, such as safety goggles, gloves, steel-toe boots, ear protection and a face shield.

A document supplied with a chemical that lists its hazards, safe handling, first-aid measures, storage requirements and spill response steps.

The grouping of fires by fuel type, where A is solid material, B is flammable liquid, C is gas, D is metal and electrical fires need a non-conducting agent.

The danger created when a lead-acid battery gives off hydrogen gas while charging, which can explode if a spark or flame is brought near the vent caps.

The sequence of intake, compression, power and exhaust strokes that a piston completes in two crankshaft revolutions in most petrol and diesel engines.

The ratio of the cylinder volume when the piston is at bottom dead centre to the volume remaining at top dead centre, affecting power and fuel behaviour.

The small gap left between the valve stem and the rocker or cam follower so the valve can close fully when the engine expands as it warms up.

The internal diameter of an engine cylinder, measured at several heights and directions to detect taper, ovality and wear before reboring or honing.

The clearance between the two ends of a piston ring when it sits squarely in the bore, checked with a feeler gauge because too little gap causes scuffing.

A sealing layer fitted between the cylinder block and head that contains combustion pressure and keeps coolant and oil in their correct passages.

The shaft that converts the up-and-down motion of the connecting rods into rotation and delivers engine output to the flywheel.

Abnormal rapid burning of the fuel-air charge that produces a metallic knocking sound and can damage pistons, often caused by low octane fuel or excessive advance.

A rating of a petrol's resistance to knocking, where a higher number means the fuel can withstand more compression before detonating.

A rating of how readily a diesel fuel ignites under compression, where a higher number gives easier starting and smoother combustion.

The exact moment, measured in crankshaft degrees, at which the injector begins to deliver diesel so combustion starts at the intended point after top dead centre.

A diesel fuel system in which one high-pressure pump feeds a shared rail that supplies all injectors, allowing electronic control of injection pressure and timing.

The computer that reads sensors such as coolant temperature, oxygen and throttle position, then adjusts fuelling, ignition and idle to keep the engine running correctly.

The vehicle's self-check system that stores fault codes and illuminates a warning lamp when sensors or emission controls report values outside the expected range.

A test instrument that measures voltage, current and resistance, used to trace open circuits, check sensor signals and confirm charging system output.

The density of battery electrolyte compared with water, measured with a hydrometer to estimate how much charge a lead-acid cell still holds.

A belt-driven generator that produces alternating current, rectifies it to direct current and recharges the battery while the engine runs.

A friction coupling between the engine flywheel and gearbox that can be engaged or released to connect and disconnect drive smoothly while changing gear.

A gear assembly that splits drive to the two wheels while letting them turn at different speeds when the vehicle corners.

Adjustment of camber, caster and toe so the wheels point correctly relative to the road and each other, preventing uneven tyre wear and pulling.

Adding small weights to a wheel rim so its mass is evenly distributed, removing vibration that appears at certain road speeds.

The height of rubber between the tread grooves and the road-contact surface, which must stay above the legal minimum to maintain grip in wet conditions.

Removing trapped air from the hydraulic brake lines by opening the bleeder screw and pumping fluid until a steady bubble-free stream appears.

A temperature-operated valve that stays closed while the engine is cold to speed warm-up, then opens to send coolant through the radiator.

A cap with a spring-loaded valve that raises the cooling system pressure, lifting the boiling point of the coolant and releasing excess pressure safely.

A measure of how thickly an oil flows at a stated temperature, shown by grades such as 10W-30 where the W indicates winter performance.

The correct handling of drained engine oil and filters, which must be stored in labelled containers and handed to an authorised recycler, never poured into drains.

A checklist carried out before a new vehicle is handed over, covering fluid levels, tyre pressures, electrical functions, road test and removal of protective films.

The workshop document that records the customer's complaint, vehicle details, work authorised, parts used, labour time and the technician's findings.

A workplace organisation method of sort, set in order, shine, standardise and sustain that keeps tools and bays clean, labelled and easy to find.

The practice of making small continuous improvements in a workshop, such as relocating a tool trolley or shortening a service step, with everyone contributing ideas.