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