RBSE Prav Voc Automotive key terms

The sequence of intake, compression, power, and exhaust strokes that a piston completes in two crankshaft revolutions to convert fuel energy into mechanical work.

The ratio of the cylinder volume above the piston at bottom dead centre to the volume remaining at top dead centre, indicating how much the air-fuel charge is squeezed.

The precise moments, measured in crankshaft degrees, at which intake and exhaust valves open and close relative to piston position, controlled by the camshaft and timing drive.

The turning effort produced by the engine at the crankshaft, measured in newton metres, which determines the load-pulling ability of the vehicle.

The rate at which the engine performs work, calculated from torque and rotational speed, usually expressed in kilowatts or horsepower at a stated engine speed.

A turbine driven by exhaust gas that spins a compressor to force more air into the cylinders, increasing power density and requiring careful lubrication and cooling.

A valve that bypasses exhaust gas around the turbine to limit boost pressure and protect the engine from over-boosting at high speed or load.

A heat exchanger that cools compressed intake air after the turbocharger, increasing its density and reducing the risk of detonation in the engine.

A friction device that engages and disengages the engine from the gearbox, allowing smooth starting from rest and interruption of drive during gear changes.

A fluid coupling in automatic transmissions that multiplies engine torque at low speed and allows the vehicle to stop without disengaging the drive mechanically.

A plate inside a torque converter that mechanically locks the turbine to the impeller at cruising speed, eliminating slip and improving fuel efficiency.

A transmission using a set of selectable gear pairs and synchronisers to match engine speed to road speed, operated by the driver through a clutch and shift lever.

A cone and hub assembly that equalises the speed of a gear and its shaft before engagement, preventing gear clash during gear changes.

A gearbox that selects gear ratios automatically using hydraulic pressure and electronic control, typically based on engine speed, throttle position, and road speed.

Adjustment of camber, caster, and toe angles so the wheels sit correctly relative to the road and vehicle body, ensuring even tyre wear and stable steering.

The inward or outward tilt of a wheel viewed from the front of the vehicle, affecting tyre contact patch, cornering grip, and wear pattern.

The difference in distance between the front and rear of a pair of wheels, set slightly inward or outward to control straight-line stability and tyre scrub.

A hydraulic damper that controls spring oscillation by converting suspension movement into heat, keeping the tyre in contact with the road.

A suspension design combining a coil spring, damper, and structural upright in one unit, widely used at the front of passenger cars for space efficiency.

The amount of charge a battery can deliver, usually rated in ampere-hours and cold cranking amps, indicating reserve and starting ability.

A belt-driven generator that produces alternating current, rectified to direct current, to charge the battery and supply electrical loads while the engine runs.

The battery, cables, relay, and starter motor circuit that cranks the engine at sufficient speed for ignition or compression ignition to begin.

A measurement of voltage lost across a cable, connection, or component while current flows, revealing high-resistance faults that a static voltmeter reading would miss.

A test instrument combining voltmeter, ammeter, and ohmmeter functions, used to measure electrical values and check continuity, resistance, and circuit integrity.

A serial data bus that lets electronic control units share sensor and status messages over a twisted pair, reducing wiring and enabling system coordination.

The computer that reads sensors and controls fuel injection, ignition timing, and emissions devices to keep the engine running efficiently and within limits.

A brake system that transmits pedal force through incompressible fluid to wheel cylinders or calipers, multiplying force through piston area ratios.

An electronic system that modulates brake pressure at each wheel to prevent wheel lock-up, preserving steering control during hard braking.

A sensor that reports each wheel's rotational speed to the ABS or stability control unit, enabling slip detection and corrective brake or torque intervention.

A system that detects loss of traction or yaw and applies individual brakes or reduces engine torque to help the driver regain the intended path.

The process of removing trapped air from hydraulic brake lines by opening bleed screws and forcing fresh fluid through until no bubbles appear.

The distance or time set by the manufacturer at which specified inspection, adjustment, and fluid replacement tasks must be carried out to maintain reliability.

A documented check of a new or repaired vehicle covering fluid levels, fastener torque, function tests, and road test before handover to the customer.

A controlled drive after repair or service to confirm that symptoms are resolved, systems function correctly, and no new faults have been introduced.

A calibrated hand tool that releases or signals at a set tightening torque, ensuring fasteners such as cylinder head bolts and wheel nuts are correctly tightened.

A set of thin metal blades of known thickness used to measure small clearances such as valve lash, spark plug gaps, and contact breaker points.

A precision measuring instrument with a calibrated screw that measures small dimensions such as shaft diameter, brake disc thickness, and piston clearance to hundredths of a millimetre.

A gauge with a spring-loaded plunger and needle dial used to measure runout, end float, and backlash on rotating or sliding components.

Items such as safety glasses, gloves, hearing protection, and safety footwear worn to reduce injury risk from chemicals, sharp edges, noise, and falling objects.

A document supplied with a hazardous substance that lists its hazards, safe handling, storage, first-aid, and spill response information for workshop users.

The design and use of extraction and airflow systems to remove exhaust fumes, solvent vapour, and dust from the work area and protect respiratory health.

A stored alphanumeric code set by an electronic control unit when a monitored circuit or signal falls outside its expected range, guiding fault-finding.

A device that connects to the vehicle diagnostic socket to read trouble codes, live sensor data, and readiness monitors from electronic control units.

A structured method of verifying the complaint, gathering information, testing to isolate the cause, performing the repair, and confirming the fix with a road test.

The traction battery, inverter, motor, and orange-coded cabling operating at hundreds of volts, requiring isolation procedures and insulated tools before work.

A strategy in hybrid and electric vehicles where the motor acts as a generator during deceleration, recovering kinetic energy to recharge the traction battery.

Electronic features such as adaptive cruise control, lane keeping, and automatic emergency braking that support the driver and require calibration after windscreen or alignment work.

A written record of a customer's complaint, authorised work, parts used, labour time, and technician notes, forming the basis for invoicing and warranty claims.

Confirming the reported symptom under conditions similar to those described by the customer before starting repairs, so effort is directed at a real fault.