How a car
turns energy into motion.

Stores low-voltage energy for starting, computers, locks, lighting, and safety systems.

Supplies electrical power and recharges the 12-volt battery while the engine runs.

Cranks the engine fast enough for combustion to begin.

Switches starter current and moves the starter pinion into engagement.

Protects wiring and devices from excessive current.

Lets a low-current control signal switch a higher-current load.

Distributes power and communication signals between components.

Provides a low-resistance return path for electrical current.

Controls fuel, ignition, throttle, emissions equipment, and engine protection.

Coordinates torque, charging, braking, thermal management, and high-voltage safety.

Coordinates lights, locks, windows, wipers, alarms, and other body functions.

Allows control units to exchange data without dedicated wires for every signal.

Reports the driver's torque request.

Tells the ECU engine speed and exact crank position.

Identifies valve-cycle phase and supports variable valve timing.

Measures the mass of air entering the engine.

Measures intake pressure for load, fueling, and boost calculations.

Let controllers protect components and regulate performance or comfort.

Reports individual wheel speed to ABS, stability control, traction control, and driver-assistance systems.

Houses cylinders, crankshaft supports, oil passages, and coolant jackets.

Forms the combustion-chamber roof and carries valves, ports, spark plugs or injectors.

Seals combustion pressure while separating oil and coolant passages.

Receives combustion pressure and transfers force to the connecting rod.

Seal combustion, control oil on the cylinder wall, and conduct heat into the block.

Transfers piston force to the crankshaft.

Converts reciprocating piston motion into rotary torque.

Support the crankshaft on a thin pressurized oil film.

Opens intake and exhaust valves at the required time and lift.

Control gases entering and leaving each cylinder.

Close valves and keep the valvetrain following the cam profile.

Transfers and sometimes multiplies camshaft motion to the valves.

Synchronizes camshaft and crankshaft rotation.

Changes valve timing to improve torque, efficiency, emissions, or power.

Smooths engine pulses and connects the engine to a clutch or torque converter.

Supports the powertrain while isolating vibration and limiting movement.

Circulates pressurized oil to bearings, valvetrain, turbocharger, and actuators.

Stores returning engine oil and encloses the crankcase.

Removes wear particles and contaminants from circulating oil.

Drives accessories such as alternator, water pump, A/C compressor, or steering pump.

Stores electrical energy for propulsion and regenerative braking.

Stores energy through reversible electrochemical reactions.

Monitors cells and enforces safe voltage, current, temperature, and charge limits.

Connects or isolates the high-voltage battery from the vehicle.

Limits inrush current when high-voltage electronics first connect.

Provides a manual means to isolate high voltage for service or emergency response.

Controls motor torque and converts between battery DC and motor AC.

Produces propulsion torque and recovers energy during regenerative braking.

Reports rotor angle and speed for precise inverter control.

Reduces high motor speed and multiplies torque before the differential.

Converts grid alternating current into controlled DC for the traction battery.

Steps traction-battery voltage down to power the 12-volt system and recharge its battery.

Provides the physical and communication interface to AC or DC charging equipment.

Carries high-voltage power with insulation, shielding, and crash protection.

Blends engine and motor power and can vary their speed relationship.

Stores liquid fuel while containing vapors and surviving normal crash loads.

Moves fuel to the injectors at the required pressure.

Traps particles before they reach pumps and injectors.

Meters and atomizes fuel for each cylinder.

Removes dust and debris from incoming air.

Regulates airflow and therefore engine load in most spark-ignition engines.

Distributes air evenly among cylinders.

Uses exhaust energy to compress intake air and increase available engine torque.

Compresses intake air using mechanical engine power.

Cools compressed intake air to increase density and reduce knock tendency.

Ignites the compressed air-fuel mixture.

Raises 12-volt power to the high voltage required for a spark.

Adds heat for reliable cold starting and early combustion stability.

Collects hot exhaust from multiple cylinders.

Measures exhaust oxygen for fuel control and catalyst monitoring.

Converts harmful exhaust gases into less harmful compounds.

Captures soot particles from diesel exhaust.

Reduces nitrogen-oxide emissions.

Reduces exhaust noise and selected frequencies.

Prevents fuel vapors from venting directly to atmosphere.

Routes blow-by gases back into the engine while controlling crankcase pressure.

Provides driver-selected gear ratios and reverse.

Selects gear ratios automatically while transmitting engine torque.

Provides rapid automated shifts with separate odd- and even-gear paths.

Varies ratio continuously across a range rather than using fixed steps.

Connects or disconnects engine torque for starting and shifting.

Transfers torque through fluid while allowing slip at idle and multiplying torque during launch.

Chooses shifts and controls clutches, line pressure, and torque coordination.

Splits torque between front and rear axles and may provide a low range.

Carries torque between separated drivetrain components.

Transmits rotation between shafts whose angles change.

Allows driven wheels to rotate at different speeds while receiving torque.

Delivers torque to an individual wheel.

Transmits torque smoothly through changing steering and suspension angles.

Supports vehicle load while allowing the wheel to rotate with low friction.

Provides the driver's primary directional input.

Transmits steering input and supports switches while collapsing in a severe frontal impact.

Converts steering-wheel rotation into lateral movement.

Converts steering input into movement of a linkage.

Sets and changes wheel toe angle under steering input.

Reduces driver effort and can support stability or parking assistance.

Carries the wheel hub and connects steering and suspension links.

Controls the wheel's path and alignment through suspension travel.

Allows steering and suspension articulation while carrying load.

Allows controlled movement while isolating noise and vibration.

Supports vehicle weight and stores energy as the wheel moves.

Supports weight and, in many layouts, locates a solid axle.

Supports the vehicle with adjustable ride height and spring rate.

Controls spring and body oscillation.

Combines damper, spring support, and upper wheel location in a compact assembly.

Resists excessive body roll during cornering while allowing both wheels to move together over bumps.

Provides accurately located mounts for powertrain, steering, and suspension.

Supports the tire and transmits forces between hub and tire bead.

Creates the contact patch that accelerates, brakes, corners, and cushions the car.

Receives the driver's deceleration request.

Amplifies driver pedal force.

Converts pedal force into hydraulic pressure.

Stores reserve fluid and accommodates pad wear and temperature changes.

Carries hydraulic pressure to wheel brakes.

Prevents sustained wheel lock and enables stability and traction interventions.

Clamps brake pads against the rotating disc.

Provides the replaceable friction material that slows the disc.

Provides a rotating friction surface and heat sink.

Provides an enclosed rotating friction surface.

Converts hydraulic pressure into outward shoe movement.

Holds a stationary vehicle independently of normal service-brake pressure.

Blends motor regeneration with friction brakes to meet the requested deceleration.

Transfers heat from coolant to outside air.

Transports heat while resisting freezing, boiling, corrosion, and electrical issues appropriate to its circuit.

Circulates coolant through heat sources and exchangers.

Speeds warm-up and regulates minimum engine temperature.

Allows coolant expansion, separates air, and provides a fill and level point.

Maintains heat-exchanger airflow at low vehicle speed or high thermal load.

Controls oil temperature under sustained load.

Removes heat from transmission fluid.

Raises refrigerant pressure so the climate system can move heat.

Rejects cabin heat carried by high-pressure refrigerant.

Meters refrigerant and creates the pressure drop needed for cooling.

Absorbs heat and removes moisture from cabin air.

Transfers coolant heat into cabin air.

Moves outside or recirculated air through filters and heat exchangers into the cabin.

Removes dust, pollen, and sometimes odors from ventilation air.

Moves ambient or component heat into the cabin more efficiently than resistance heating in suitable conditions.

Combines passenger enclosure and primary load-bearing structure.

Carries powertrain, suspension, body, towing, and payload loads.

Spreads low- and moderate-speed impact loads across the structure.

Absorbs lower-energy impacts and can reduce damage to the main body structure.

Maintains survival space and manages impact loads around the cabin.

Extends crash stopping time and absorbs kinetic energy before it reaches occupants.

Limits door intrusion and spreads side-impact loads.

Closes the compartment and remains secured during driving and many impacts.

Provides access while contributing to sealing, side protection, and structural continuity.

Raises, lowers, and supports the window glass.

Provides rearward visibility and may house cameras, indicators, heaters, or blind-spot warnings.

Controls spray, debris, airflow, noise, and component exposure.

Restrains the occupant and spreads crash loads across strong parts of the body.

Removes belt slack at the beginning of a severe crash.

Controls peak belt force on the occupant's chest.

Provides a temporary energy-absorbing surface during selected crash modes.

Detects crash severity and commands appropriate pretensioners, airbags, and isolation actions.

Supports occupants during normal driving and helps manage loads in a crash, including rear-impact neck motion.

Provides vision, weather sealing, occupant retention, roof support contribution, and a mounting view for sensors.

Provides visibility and enclosure while breaking in a controlled manner.

Moves wiper blades across the glass at controlled speeds.

Applies cleaning fluid to improve visibility.

Illuminates the road and makes the vehicle visible.

Communicates vehicle presence, braking, and intended direction.

Provides an audible warning to other road users.

Warns when tire pressure is significantly low.

Detects lanes, signs, vehicles, pedestrians, and visual features for driver assistance.

Measures object range and relative speed in poor or good visibility.

Detects nearby obstacles at low speed.

Helps keep the car following the driver's intended path near the limits of grip.