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I'm Jake O 'Neill, creator of Animagraffs,

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and this is how a car engine works.

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Let's start at a single piston,

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the powerhouse of the engine, and work our way outwards.

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The 4 stroke cycle.

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When a piston travels to the end of its range,

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whether up or down, that's a stroke.

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Car engines use a 4 stroke cycle, and it goes like this.

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First, intake.

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The piston descends,

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sucking an air-fuel mixture into the cylinder through the

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intake port, with both intake valves open.

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Next, compression.

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With all valves closed, the piston comes back up,

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compressing the fuel and air mixture for more powerful

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combustion.

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Then, the power stroke.

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An electrical spark ignites the compressed fuel and air

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mixture,

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and the resulting combustion forces the piston to the

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bottom of the cylinder again.

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A connecting rod transfers this power to the crankshaft.

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Finally, exhaust.

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The piston comes back up,

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pushing the spent mixture out through open exhaust valves

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and the exhaust port connecting multiple pistons.

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For smooth power delivery, pistons take turns firing.

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The firing order for this engine is one, three, four, two.

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Camshafts, with specially shaped cams,

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push spring-loaded valves open in turn.

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Cam gears and a timing belt or chain links everything to

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the crankshaft, and it all spins together.

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The crankshaft translates piston power out of the engine.

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It has counterweights to balance against the pistons for

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perfectly smooth revolutions.

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This is what RPM means.

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We're counting the number of full crankshaft revolutions

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per minute.

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The engine block holds the crankshaft and cylinders and the

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cylinder head holds valves, ports, cams, etc.

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The geared flywheel sits at one side of the crankshaft for

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connection to a transmission.

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It's also where the starter connects to the system.

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This engine has four cylinders arranged in a single row,

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but there are many other possible configurations,

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like six cylinders with three on each side,

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angled in a v-shape, or eight.

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Despite different design goals,

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the basic engine parts are all there.

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Now let's look at other systems that support this

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combustion process.

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Air intake.

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Air comes in through the air filter and then into the

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intake manifold where it mixes with fuel before being

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sucked into individual cylinders through intake ports.

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Fuel.

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The fuel pump carries gas from the tank through a fuel

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filter to the engine where fuel injectors emit a precisely

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timed spray of gas into the intake port.

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Cooling.

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Engines get very hot during operation and require a cooling

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system.

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Coolant channels around the cylinders and through the

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cylinder heads carry a special liquid called antifreeze to

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keep temperatures within safe operating range.

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It's called antifreeze because it won't freeze in icy

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weather.

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After cooling hot engine parts,

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coolant circulates through the radiator.

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The radiator has a network of small tubes and fins.

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Coolant passes through these channels while air pulled in

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by the radiator fan blows by the tubes,

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cooling the hot liquid for recirculation.

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A water pump keeps the coolant system flowing and properly

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pressurized.

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The thermostat regulates coolant temperature by either

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routing coolant back through the engine or to the radiator

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for further cooling.

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Electrical.

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The spark plug delivers the electrical spark that ignites

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the fuel-air mixture for combustion.

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The metal core is insulated from the outer metal casing

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with porcelain.

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The spark jumps between these conductive surfaces.

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A coil pack delivers electrical current to the spark plugs

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as directed by the ECM, or Engine Control Module.

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The ECM is a computer that directs many core engine

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functions like spark timing, valve open and close timing,

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air to fuel ratio, etc.

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The alternator works like a power generator,

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converting the engine's mechanical energy into electricity

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to charge the battery or run other electrical systems while

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the engine is running.

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The battery provides power to the starter for engine start.

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Oil.

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Motor oil is used to lubricate, clean, prevent corrosion,

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improve sealing,

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and cool the engine by carrying heat away from moving

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parts.

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Rings around the top of the piston head keep oil out of the

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combustion process,

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while otherwise allowing the cylinder to be lubricated.

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Oil galleries are channels through the engine block and

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cylinder head that carry oil to various engine parts.

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Oil flows through the engine and back to the oil pan for

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recirculation.

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Oil rests in the oil pan when not in circulation.

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The oil pump keeps oil properly pressurized and flowing.

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And the oil filter keeps oil clean from contaminants.

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Exhaust.

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The exhaust manifold collects gases from multiple cylinders

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into one pipe.

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Exhaust flows through the catalytic converter which

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captures toxic chemicals in engine exhaust and then out

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through a muffler that reduces exhaust noise.

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And finally,

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here's the full functioning engine with all the basic

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systems we've discussed.