Gas & Air

[Noviisi]

I haven't been working on cars that much so I figured it would be way cool if somebody would explain some fundamentals of our 2.0L engine. The little I know is this: you need both gas and air to make the car move. What puzzles me most at the moment is this:

a) the journey GAS has to make before it explodes inside the cylinder. what are the exact parts on its way to cylinder.
and which parts are most vulnerable to break down

b) the journey of AIR to cylinder + parts + vulnerable parts

(please include sensors. at which point do gas and air mix together?)

Million thanks!

[gilligan]

I'll try to help a little bit.

1. the fuel pump in the tank sends gas at a pretty high psi but not sure how high.
then the fuel pressure regulator on the end of the fuel rail only allows so much pressure through it and the excess goes via another line back to the tank.
that help's to keep the fuel pump running freely so it doesnt burn up.
once the fuel at the proper pressure makes it through the pressure regulator it travels down the fuel rail which is connected to all four injectors.

2. The air travels through the filter and past the maf (mass Air Flow Sensor) which helps the computer to determine by how much air is flowing into the motor as to how much fuel to let through the injectors.

the computer also takes readings from the 02 sensor's in the exhaust to determine if it is actually doing a good job at metering the fuel to the motor.

just before the Air enters the cylinder head the fuel is injected into it.

Which parts are most likely to breakdown??
1. 02 sensor's
2. Vaacuum line to fuel regulator
3. Maf
4. Cat
5. ECU

Hope this helped.
Feel free to correct me if I'm wrong I don't know everything .

[hannaco]

The next item to look at is the spark needed to set the fuel and air mixture on fire. The ECU gets a signal from the crank position sensor so it knows when to fire off each cylinder. The ECU sends a signal to the coil pack which generates a high voltage current that flows down the spark plug wires to the spark plugs. The current jumps the gap in the plug lighting off the fuel and air mixture.
The ECU takes signals from the MAF, O2 sensors, and TPS (throttle position sensor), temperature sensor, and to a limited degree the MAP sensor to meeter the correct amount of fuel through the injector, and set off the spark at just the right time.
Items that go bad are usually the spark plugs, and spark plug wires. Things that fail less often are the O2 sensors, coil pack, and on a limited basis the crank position sensor.

[Noviisi]

Quick question: What is the MAP sensor? What does it do and where is it located? How is it different from the allmighty MAF?


Thank you for great input! I'll keep asking more questions soon. Just have to meditate on the present info first.

[vdubbugman53]

in addition when the pistons are on the down stroke the cam lifts the intake valve letting the engine suck air in on the up stroke the air is compresses fuel is injected and spark is fired creating a combustion. piston goes up and the cam then lifts the exhaust valve and blows the exhaust out......just remember: suck, squeez, bang blow.


in the 2.0 you always have 2 pistons up 2 pistons down. so you have 1 and 4 up and you have 2 and 3 down.....when piston 1 is sucking air piston 4 is beiing combusted when piston 2 and 3 are on their way down after being combusted then you have piston 1 compressing air to be combusted and piston 4 will be exhausting gas.


http://auto.howstuffworks.com/engine1.htm

[hannaco]

MAP - Manifold Absolute Pressure
This is used by the ECU as a check against the MAF.
The IAT (Intake Air Temperature) is measured in the MAF housing.
The ECU uses the IAT, and MAF readings to determine the air/fuel density in the cylinder. It then determines the spark advance. If everything is done correctly you get a nice clean burn.

[LadybugEwa]

What an awesome thread! Keep'em coming, guys. I'm learning so much. The only way this could get better is if you posted diagrams

[Noviisi]

Thanks everybody!

So, after short meditation I think I understand something about the fuel system. Before your answers I had now idea that something like fuel pressure regulator even exists.
By the way, where exactly does the fuel pressure regulator hide?
Near engine compartment?
Are there any sensors involved? (ECU wants to know everything whats going on, right? )

This is my attempt to visualize things said here about the Fuel system. Please correct me and make adjustments.