1. Air filter
   Cross-bolted bearing
2. Connecting rod
   Radiator

The connecting rod connects the piston to the crank or crankshaft. It converts reciprocating motion into rotating motion.

1. Gudgeon pin
   Exhaust system
2. Rocker arm
   Ignition coil

The gudgeon pin is also called the wrist pin or the piston pin. It connects the piston to the connecting rod and also provides a bearing for the connecting rod when the piston moves.

1. Valvetrain
   Connecting rod cap
2. Engine block
   Water pumps

The connecting rod cap is used to clamp around the crankshaft and the big-end bearing. Connecting rods and matching rod caps are sometimes constructed together as one piece.

1. Starter ring gear
   Oil pump
2. Spark plug
   Oil filter

Automobile engines of the past didn’t use oil filters, which is why very frequent oil changes were required. The first automotive oil filter was invented in 1923.

1. Unit injector
   Thermo switch
2. Alternator
   Mass flow sensor

The unit injector (UI) is an integrated direct fuel-injection system for diesel engines. It operates under high pressure, combining the injection pump and the injection nozzle in a single component.

1. Thermostat
   Tensioner
2. Cooling fan
   Wastegate

Every belt-driven engine has a timing belt, a tensioner and several pulleys. The tensioners ensure the correct amount of tension is applied to the belt.

1. Screamer pipe
   Connecting rod bearings
2. Intercooler
   EGR Valve

Exhaust gas recirculation (EGR) recirculates a portion of an engine’s exhaust gas back to the engine cylinders in internal combustion engines.

1. Injection pump
   Cooling fan
2. Crankshaft
   Intake manifold

The cooling fan allows the engine to maintain constant temperature. Front-wheel drive cars have electric fans while rear-wheel drive cars usually have engine-driven cooling fans.

1. Oil-pressure switch
   Main crankshaft bearings
2. Piston rings
   Poppet valve

Depending on the engine construction, the oil pressure switch is usually located in one of these three locations: the cylinder block of the engine, the oil filter housing or the engine head.

1. Cylinder head
   Thermostat
2. Carburetor
   Piston

The thermostat is a small device found in every liquid-cooled car engine. Its role is to block the coolant flow from reaching the radiator until the engine has warmed up.

1. Vacuum modulator
   Intake manifold
2. Catalytic converter
   Rocker arm

A catalytic converter converts toxic gasses and pollutants in exhaust gas from internal combustion engines into harmless compounds by using a catalyst.

1. Cylinder head
   Mass-flow sensor
2. Connecting rod bearings
   Wastegate

A mass-flow sensor determines the mass-flow rate of air that enters a fuel-injected internal combustion engine. This information is then used by the ECU to deliver the optimal fuel mass to the engine.

1. Injection pump
   Vacuum modulator
2. Exhaust system
   Connecting rod

Some cars use a vacuum modulator to apply pressure to the throttle valve. It senses when the manifold pressure increases (when the engine is under a great load).

1. Alternator
   Valvetrain
2. Intercooler
   Screamer pipe

Modern automobiles use alternators to charge the battery and power the electrical system while the engine is running.

1. Gudgeon pin
   Oil filter
2. Piston
   Engine block

A piston survives thousands of mini explosions each time you use your car. It has a top and a bottom, and the top is where the explosions happen.

1. Cooling fan
   Thermo switch
2. Unit injector
   Injection pump

The thermo switch is a temperature sensor. The device is usually located close to the radiator, and its role is to switch on the fan as soon as the engine reaches a set temperature.

1. Carburetor
   Rod cap
2. Main crankshaft bearings
   Poppet valve

A carburetor mixes air and fuel for internal combustion engines into the optimal ratio for creating combustion. The first carburetor was invented in 1826 by Samuel Morey.

1. EGR valve
   Catalytic converter
2. Spark plug
   Air filter

Bosch's engineer Gottlob Honold developed the first commercially viable high-voltage spark plug as part of a magneto-based ignition system in 1902.

1. Crankshaft
   Cylinder head
2. Tensioners
   Catalytic converter

The cylinder head is placed above the cylinders on top of the cylinder block. Its job is to close the top of the cylinder and form a combustion chamber.

1. Oil pump
   Connecting rod
2. Unit injector
   Mass-flow sensor

The purpose of the oil pump in internal combustion engines is to lubricate the bearings and allow the use of higher-capacity fluid bearings. It also has a significant part in engine cooling.

1. Cross-bolted bearing
   Crankshaft
2. EGR valve
   Poppet valve

A poppet valve consists of a hole, in most cases round or oval, and a tapered plug usually in a disk shape on the end of the shaft also called valve stream.

1. Oil-pressure switch
   Starter ring gear
2. Oil filter
   Thermostat

A starter ring gear is sometimes called a ring gear or a starter ring. It’s a medium carbon steel ring that’s fitted on the periphery of the flexplate or flywheel.

1. Piston rings
   Mass flow sensor
2. Cooling fan
   Carburetor

The first split piston ring was invented by John Ramsbottom in 1854. The use of piston rings dramatically reduced the frictional resistance, piston mass and system leakage.

1. Valvetrain
   Injection pump
2. Water pump
   Exhaust system

The role of the water pump is to ensure the coolant keeps moving through the engine block, radiator and hoses, making sure optimum operating temperature is maintained.

1. Gudgeon pin
   Vacuum modulator
2. Thermo switch
   Main crankshaft bearings

Main crankshaft bearings are mounted in the crankcase. A main bearing consists of two parts: upper and lower.

1. Engine block
   Ignition coil
2. Catalytic converter
   Oil filter

An engine block is also commonly called cylinder block. It’s a structure in which the cylinders are placed in an internal combustion engine. Modern engine blocks usually include several other elements, too.

1. Wastegate
   Intake manifold
2. Cylinder head
   Thermostat

The intake manifold is a pipe connected to the intake valves. Its role is to bring air or air-fuel mixture into the combustion chamber.

1. Thermo switch
   Spark plug
2. Valvetrain
   Tensioners

Valvetrains (or valve trains) are produced in several variations that are differentiated by the location of the camshaft within the engine.

1. Piston
   Crankshaft
2. Vacuum modulator
   Rocker arm

The crankshaft is a mechanical part of a car engine that converts reciprocating motion into rotational motion and vice versa.

1. Intercooler
   Carburetor
2. Starter ring gear
   Ignition coil

The role of the ignition coil is to generate a very high voltage from a car’s 12-volt battery – and to send it to each sparkplug, igniting the air-fuel mixture in the combustion chamber.

1. Injection pump
   Screamer pipe
2. Starter ring gear
   Rod cap

An injection pump is a very complex and sophisticated piece of engineering. It pumps diesel fuel into the cylinders of a diesel engine.

1. Thermo switch
   Connecting rod bearings
2. Rocker arm
   Water pumps

The rocker arms are placed in the drive train of the internal combustion engine. Their function is to assist the pushrod in the opening and closing of the exhaust valve and intake valve.

1. Oil filter
   Piston
2. Cylinder head
   Intercooler

Intercoolers reduce the induction air heat created by the supercharger and promote more thorough combustion by increasing the efficiency of the induction system.

1. EGR Valve
   Exhaust system
2. Mass flow sensor
   Oil pump

An exhaust system consists of pipes that guide reaction exhaust gases away from a controlled combustion inside an internal combustion engine. Depending on its overall design, it may include one or more pipes.

1. Alternator
   Tensioners
2. Connecting rod bearings
   Connecting rod

The connecting rod bearings are placed in the big end of the connecting rod. They have a role of providing rotating motion of the crank pin within the connecting rod.

1. Wastegate
   Radiator
2. Piston rings
   Engine block

In cars with liquid-cooled internal combustion engines, the radiator is connected to channels running through the engine and cylinder head, through which a coolant is pumped.

1. Screamer pipe
   Cylinder head
2. Thermostat
   Piston

When it comes to the screamer pipe, opinions are divided: some people think these things make the worst noise they have ever heard, while others think it sounds pretty good and powerful.

1. Oil-pressure switch
   Main crankshaft bearings
2. Mass-flow sensor
   Wastegate

A wastegate is a boost-controlling device that operates by limiting exhaust gases through the turbocharger and controlling the maximum boost pressure the turbocharger produces.

1. Air filter
   Spark plug
2. Unit injector
   Intercooler

The air filter in internal combustion engines prevents debris and any abrasive particulate substance from entering the cylinders of the engine.