Originally posted by Graceilyons64
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Answer: "Sorta of yes but in a nutshell "NO!" .... lol ... I will try and keep it simple as to not confuse as No:1 is only part of the full firing cycle for all of the 4 x cylinders.
Theory in my head is allot easier to construct as appose to correlating it into words that can be understood in a simple manner?
REASON: There is 2 x full crankshaft revolutions to one firing cycle!.. By the time the crankshaft has done 2 x full crank revaluations (720 Deg) all 4 x cylinders would have fired!.. With this in mined, if the engine stops on No:4 cylinder, when you turn the ignition key back on it will carry on the firing cycle from where it initially stopped! That is why there is a cam shaft and crank angle sensor! So that the ECU (Electronic Control Unit) knows exactly what and which cylinder Intake/Exhaust valves are open/closed and where exactly the pistons are siting in the cylinder bore!
EG:1 by the time the crank shaft has done 2 x full revolutions (720 Deg) all 4 x cylinders will have fired simultaneously! ... firing order 1-3-4-2!
I will concentrate on the full firing cycle of "ONE" cylinder only then imagine all four cylinders firing consecutively 1-3-4-2 within two full crank revolutions.
EG:2 Induction = downward stroke/ combustion = upward stroke (360 deg)/ Power = downward stroke/ Exhaust = upward stroke!.. (720 deg) Better to simplify as suck/ Squeeze/ Bang/ Blow!
No gutter talk at this point please guys!.. Lol
EG:3 In one full crank revolution (360 Deg) the piston has traveled from the top of the cylinder bore (TDC = Top Dead Center) to the bottom (BDC = Bottom Dead Center) and then back to the top of the cyder (TDC). This one cycle (360 deg) accounts for "Induction, combustion" (Suck/ Squeeze).
The next crankshaft rotation (360 Deg) will be again from the piston traveling from the top of the cylinder again then to the bottom then back up to TDC again!.. Only this time it will be the finishing the complete firing cycle. "Power = Downward stroke/ Exhaust = Upward stroke" (Bang/ Blow)...
RECAP:
#1 Induction (suck) (inlet valve opens), By the time the piston reaches the bottom of the cylinder the inlet valve is closed.
#2 Combustion (squeeze) (All valves are closed). piston travels to the top of the cylinder compressing fuel/air mixture.
#3 Power (bang) (Fuel/ air has been ignited pushing the piston back to the bottom of the cylinder) All valves still closed on the power stroke.
#4 Exhaust (blow) (As the piston returns back up the cylinder the exhaust valve is opened and gases are pushed out the exhaust to drive the turbo!
I did not include valve overlap etc as kept it to the simple explanation!
As you can imagine it is much more complex than i have described but you get the picture!... I hope!... Lol
Originally posted by Graceilyons64
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Hope it helps explain a few things for you!
Cheers
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