Basic Working of an Engine

[Recarobalt_RLC]

ok so i am kinda bored at work today so i figured i would write this up on this slow rainy day...

lets start with the 4 main functions... aka strokes
Suck - piston goes down pulling air in though your open intake valves
Squeaze- piston goes up compressing the air above the cylinder (both valves are closed)
Bang- the spark plug fires pushing the piston back down ( which will cause the crank to spin )
Blow- piston comes back up pushing all the burnt air (exhaust) out of the open exhaust valves

thats how a 4 stroke works

detail of the strokes
now cuz we have a 4 cylinder each piston is at the begining of a different stroke all at the same time. so when one piston is banging (forcing the piston down and spinning the crank shaft a half a rotation) another piston is is going up and squeazing, another is falling down sucking air in and another is blowing exhaust out. now that that stoke is done the piston that was just squeazing is now banging... the piston that was just sucking air in is now going up (squeazing)... the piston that was just blowing exhaust out is now sucking air in... and the piston that just banged is now being pushed back up blowing the exhaust out. i think you got the drift now...

lets move a little further...
we have 4 valves per cylinder 2 intake and 2 exhaust. you intake air obviously comes through you air intake through the throttle body into your intake mani (or Supercharger) then intake mani) and divided into four different chambers located in your head... one per cyinder. each port has a fuel injector located in it, misting gas into your air. (the car knows how much gas to mix with the air due to sensors reading air flow, known as AFR, with tuning you can adjust this) now you have a gas air mix that flows up to the valves and when they are open (on the suck or intake stroke) they will flow down into the cylinder.

Cams are what control the valves to open and close... we have a dual over head cam... that means we have 2 cams and they are located at the top of the motor... one cam is your intake cam and the other is the exhaust. the cam has lobes that are egg shaped on it. the lumps cause the valves to go up and down... the cams are spun by gears located at one end of them... cam gears... these gears have a belt or chain on them (we have a chain) that goes down to a gear on the crank... so when the crank turns the cams turn... how ever due to gear sizing it take 2 turns of the crank to turn the cam gear one time. why you ask? because if you look at the strokes the valves only have to open one time in a cycle of four strokes... each stroke is a half turn of the crank...so the crank turns 2 times and each cylinder will only fire once in both turns of the crank.

how do you get spark?
well just like the rest of the engine it all works together. at the end of one cam there wil be a distributer or a electronic cam time reader (i cant think of what its called right now) the distributor gets spun inside by the cam shaft... when it is spun it turns a connector that will tap different connectors, that are perfectly space, giving power to each wire one at a time... at the perftect time. the wire gives power to your spark plug giving you a spark in the cylinder exploding your perfect mix of air and fuel. (that was a very basic explanation or how a distributer works) and the electronic read is what we have... it reads it electronicly and has the computer tell the plugs when to spark... but similar concept just not as machanical.

Throttle
when you accelerate, you push the pedal down more... this opens your throttle body more which allows more air in which the computer will read and add more gas to for a bigger bang... when this happens your crank will start spinning faster and faster... due to the bigger bangs and more rapid air flow and strokes.

How your Forced induction works
some cobalts are supercharged (some SS models) a super charger is a form of forced induction. it forces air in insted of the suck stroke sucking the air in.
You have belts on the front side of your motor (passanger side on cobalts- front of motor is where your cam gears are) these are also spun by the crank shaft... you have a crank pulley that is connected to it that spins your belt drive system. the belts are on both FI and NA cars... the belts spin you alternater, pump and different things the motor uses... it is different per motor and car... the FI supercharger uses this belt system to spin a (this is being really basic haha) FAN or the supercharger, which is forcing air into the motor.
Turbos dont use the belt drive system. they use your exhaust... the flow of exhaust out of the car is what does it... your exhaust will comeout of an exhaust manifold or some of you say header (we wont get into proper names for that) the header combinds all four exhaust ports down to one tube... on turbo cars the tube will go into one side of the turbo...and then back out... the flow of air spins the turbine... which spins the turbine on the other side of the turbo. which is like a fan... it sucks air in and compresses it into the motor... now the turbo will be located on the back of the motor so the intake air has to run though a pipe to the intake mani/throttlebody... but because the exhaust is so hot and that is what is used to spin the turbo the intake air gets really hot... so most of the time you have an intercooler... air flows from the turbo to the intercooler then to the throttlebody then through the intake mani and into your intake ports on the head.

Other
oil is used to lubricate the motor, beacause you have so many metal on metal moving parts that need to last a long time you have to keep them lubricated with oil.
coolant is what keeps the motor cool enough to run (still very hot, but it keeps it in operating temp) your coolant is a liquid that runs through ports and channels in the motor... when it comes in it is cooler and it cools the metal and takes the heat out... by the time it comes out of the motor it is hot... so it needs to cool down before going back in. so it goes through the radiator... mounted on the front of the car, air flows through the fins and cools the radiator... the radiator acts like the motor but does the oposite.. it cools the liquid passing through it. the coolanted is moved through the system by a pump.

Air fuel ratios and more
most of you heard that the recamended idle AFR is 14.7.. but do you know what it means? it means 14.7 parts air and 1 part fuel... its the mixture of gas and air... safe AFRs are 14.7 at idle and mid low 12s at wide open throttle... but that part can vary... a smaller number makes it more rich... a higher number makes it more lean.... rich is more gas then normal. lean is less then normal.
too lean is bad becuase gas also cools your motor... it cools the cylinder when it enters it. if you get lean you wont have as much power, but it can also over will heat your motor and cause alot of problems.
too rich is also bad... if you get to rich you can wash the cylinder walls... basically flood out the motor with gas.. and it can slip past the pistons down into your oil.. damaging things and giving you more blow by.

well thanks for reading it all and i hope this helped you.... you can let me know of any mistakes i have or anything you want me cover more or have questions... and i know there is most likely a lot of spelling mistakes... blow me haha

[xxcooljay23xxg5]

good write!

[BlackBaltSS]

sticky for n00bs

[DJVC]

I want your job! Just riding the clock doing write ups lmao

But awesome write, helped me understand my engine alittle better.
STICKY!

[Recarobalt_RLC]

haha i dont get paid per hour... its a standard flat rate per week... and commisison...

[jay DuB]

u should throw this write up on wikipedia ..lol

[cobaltkrazy]

I vote Stick-Icky!!!!!!!!!!!!

nice write up recaro

[Recarobalt_RLC]

thanks guys