[0:00] I'm Jake O'Neal, creator of Animagraffs. 
And this is how a Car Engine works.
[0:07] Let's start at a single piston, the powerhouse 
of the engine, and work our way outwards.
[0:14] The four stroke cycle
[0:17] When a piston travels to the end of its 
range, whether up or down, that's a stroke.  
[0:24] Car engines use a four stroke 
cycle, and it goes like this:
[0:30] First, intake. The piston descends, sucking 
an air-fuel mixture into the cylinder  
[0:36] through the intake port, 
with both intake valves open.
[0:42] Next, compression. With all valves 
closed the piston comes back up,  
[0:48] compressing the fuel and air mixture 
for more powerful combustion.
[0:54] Then, the power stroke. An electrical spark 
ignites the compressed fuel and air mixture,  
[1:02] and the resulting combustion forces the 
piston to the bottom of the cylinder again.  
[1:07] A connecting rod transfers 
this power to the crankshaft.
[1:12] Finally, exhaust. The piston comes back up,  
[1:17] pushing the spent mixture out through 
open exhaust valves and the exhaust port.
[1:23] Connecting multiple pistons
[1:26] For smooth power delivery, pistons take turns 
firing. The firing order for this engine  
[1:32] is 1-3-4-2. Camshafts with specially shaped 
cams push spring-loaded valves open in turn.  
[1:45] Cam gears and a timing belt or chain 
links everything to the crankshaft,  
[1:51] and it all spins together.
[1:56] The crankshaft translates 
piston power out of the engine.  
[2:00] It has counterweights to balance against the 
pistons for perfectly smooth revolutions.
[2:07] This is what RPM means -- we're counting the 
number of full crankshaft revolutions per minute. 
[2:16] The engine block holds the crankshaft 
and cylinders, and the cylinder  
[2:21] head holds valves, ports, cams, etc.
A geared flywheel sits at one side of the  
[2:28] crankshaft for connection to a transmission. It's 
also where the starter connects to the system. 
[2:36] This engine has four cylinders 
arranged in a single row.  
[2:40] But there are many other possible configurations, 
like six cylinders with three on each side, angled  
[2:46] in a V shape. Or eight. Despite different design 
goals, the basic engine parts are all there. 
[2:55] Now let's look at the other systems 
that support this combustion process.
[3:03] Air intake
Air comes in through an air filter,  
[3:10] and then into the intake manifold where 
it mixes with fuel before being sucked  
[3:15] into individual cylinders through intake ports.
[3:25] Fuel
The fuel pump carries gas from the tank,  
[3:36] through a fuel filter, to the engine 
[3:39] where fuel injectors emit a precisely 
timed spray of gas into the intake port.
[3:54] Cooling
Engines get very hot during operation  
[3:58] and require a cooling system. Coolant channels 
around the cylinders and through the cylinder  
[4:05] heads carry a special liquid called "anti-freeze" 
to keep temperatures within safe operating range.  
[4:12] (It's called anti-freeze because 
it won't freeze in icy weather). 
[4:18] After cooling hot engine parts, coolant 
circulates through the radiator.  
[4:23] The radiator has a network of small tubes and 
fins. Coolant passes through these channels while  
[4:30] air (pulled in by the radiator fan) flows by the 
tubes, cooling the hot liquid for recirculation. 
[4:44] A water pump keeps the coolant system 
flowing and properly pressurized. 
[4:51] The thermostat regulates coolant 
temperature by either routing coolant back  
[4:55] through the engine or to the 
radiator for further cooling.
[5:02] Electrical 
[5:05] The spark plug delivers the electrical spark 
that ignites the fuel-air mixture for combustion.  
[5:11] The metal core is insulated from the 
outer metal casing with porcelain.  
[5:15] The spark jumps between these conductive surfaces.
The coil pack delivers electrical current to the  
[5:27] spark plugs as directed by the ECM (engine 
control module). The ECM is a computer that  
[5:36] directs many core engine functions like spark 
timing, valve timing, air to fuel ratio, etc. 
[5:45] The alternator works like a power generator, 
converting the engine's mechanical energy into  
[5:50] electricity to charge the battery or run other 
electrical systems while the engine is running. 
[5:59] The battery provides power to 
the starter for engine start.
[6:07] Oil
Motor oil is used to lubricate,  
[6:11] clean, prevent corrosion, improve sealing, and 
cool the engine by carrying heat away from moving  
[6:16] parts. Rings around the top of the piston head 
keep oil out of the combustion process while  
[6:25] otherwise allowing the cylinder to be lubricated.
Oil galleries are channels through the  
[6:30] engine block and cylinder head that 
carry oil to various engine parts.
[6:38] Oil flows through the engine and back 
to the oil pan for recirculation. 
[6:41] The oil pump keeps oil properly 
pressurized and flowing. 
[6:45] Oil rests in the oil pan when not in circulation.
The oil filter keeps oil clean from contaminants.
[7:04] Exhaust 
[7:10] The exhaust manifold collects gases 
from multiple cylinders into one pipe. 
[7:17] Exhaust flows through the catalytic converter, 
which captures toxic chemicals in engine exhaust. 
[7:23] And then out through a muffler 
that reduces exhaust noise.
[7:29] Full model
And finally,  
[7:31] here's the full functioning engine with 
all the basic systems we've discussed.