Major Systems and Components of an Automobile Engine

Comprehensive vocabulary flashcards covering the components, operational principles, and mechanisms of internal and external combustion engines.

Engine

A complex unit in which different components are assembled together and fuel is burned to convert chemical energy (heat energy) into mechanical energy for vehicular movement.

Internal Combustion (IC) Engine

An engine in which fuel combustion takes place directly within the engine itself to produce power.

External Combustion (EC) Engine

An engine in which fuel is burned externally to generate steam, which is then utilised to produce mechanical movement.

Wankel Engine

A rotary engine in which an internal rotor rotates to complete the combustion process and generate driving power.

Spark Ignition (SI) Engine

An engine running on highly volatile fuel (such as gasoline) where a premixed air-fuel charge enters the cylinder, is compressed by a piston, and is ignited by an electric spark.

Compression Ignition (CI) Engine

An engine in which fresh air is compressed to a high temperature of up to $1000^\circ\text{F}\,(538^\circ\text{C})$ and high pressure, after which atomised diesel fuel is injected and ignited purely by the heat of compression.

Cylinder Block

The single-casted main body of an engine housing the cylinder liners, water passages for heat dispersion, oil passages for lubrication, and the crankcase.

Cylinder Liner

A sleeve fitted into the cylinder block that withstands pressures of about $70\,\text{bar}$ and temperatures of about $700^\circ\text{C}$, often coated internally with titanium for mirror finish and wear resistance.

Cylinder Head

A single-casted unit bolted to the top of the cylinder block that houses the combustion chamber, spark plugs or fuel injectors, and valve mechanisms.

Cylinder Head Gasket

A single-piece gasket composed of copper and asbestos fitted between the cylinder block and cylinder head to create a gas-tight seal.

Piston

A cylindrical component made of lightweight, high-thermal-conductivity aluminium alloy that reciprocates between TDC and BDC to compress the charge and transmit gas force to the connecting rod.

Piston Rings

Special grade cast-iron rings seated in piston grooves that maintain elasticity at high temperatures to provide sealing against gas leakage and regulate lubrication.

Compression Rings

The upper piston rings designed to seal the clearance between the piston and cylinder liner to prevent high-pressure gas blow-by.

Oil Control Rings

The lower piston rings that scrape and regulate lubricating oil along the cylinder wall.

Connecting Rod

An I-shaped member made of drop-forged steel that connects the piston to the crankshaft, converting reciprocating motion into rotary motion.

Crankshaft

The backbone of an engine made of drop-forged steel that transforms the reciprocating motion of the pistons into continuous rotary motion.

Gudgeon Pin (Piston Pin)

A pin that passes through the piston to connect it to the small end of the connecting rod, secured against the cylinder wall by circlips.

Inlet Valve

A valve with a wide face that controls the admission of fresh air-fuel mixture (petrol) or fresh air (diesel) into the cylinder during the suction stroke.

Exhaust Valve

A heat-resistant valve that opens following the power stroke to discharge burned combustion gases from the cylinder into the exhaust manifold.

Valve Spring

A spring with machined ends that keeps the valve closed, provides an airtight seal against combustion gases during the power stroke, and ensures self-centering movement.

Inlet Manifold

A ducting system that delivers the air-fuel mixture from the carburettor or fresh air from the throttle body/intake directly to the engine cylinders.

Exhaust Manifold

A set of pipes coupled to a muffler that directs burned exhaust gases out of the exhaust ports while integrating oxygen sensors and catalytic converters.

Camshaft

A shaft driven by the crankshaft at half of the crankshaft's rotational speed, fitted with cam lobes to actuate the intake and exhaust valves.

Bucket Tappet

A cylindrical component situated directly below a cam lobe that is pushed downward by the cam lobe to open the engine valve.

Push Rod

A rigid rod that transfers upward reciprocating motion from the cam follower/valve lifter to the rocker arm.

Rocker Arm

A pivoted lever that reverses the upward push of the push rod into a downward motion against the valve stem to open the valve.

Crankcase

The integrated lower housing of the cylinder block that encloses the rotating crankshaft and connects at the bottom to the oil pan.

Water Pump

A mechanical device that draws coolant from the radiator and forces it under pressure through water jackets in the engine block and cylinder head.

Radiator

A cooling system heat exchanger containing upper and lower tanks connected by a central core that dissipates heat from circulating engine coolant.

Flywheel

A heavy wheel bolted to the rear flange of the crankshaft that accumulates energy during the power stroke to maintain uniform rotation and transmits drive to the clutch.

Governor

A crankshaft-driven regulatory device that adjusts the charge in a petrol engine or fuel quantity in a diesel engine to hold engine speed constant under varying loads.

Carburettor

A device fitted to the induction manifold of a petrol engine that atomises and meters the fuel-air mixture in proportions determined by engine speed and load.

Spark Plug

A threaded electrical component located in the cylinder head of a petrol engine that produces a spark to ignite the compressed fuel-air charge.

Fuel Injection Pump

A high-pressure pump in a diesel engine that draws fuel from the tank, elevates its pressure via a transfer pump, and delivers it to the distributor rotor and injectors.

Fuel Injector

A precision nozzle that delivers fuel into the combustion chamber or manifold in a finely atomised spray for efficient burning.