i have a 95 accord ex single cam vtec. f22b1

okay.. i understand how a basic internal engine work. but i was thinking.. that since i have one camshaft.. when the camshaft spin. the lobes hit the rocker arm to open the valve.. does all 4 cylinder gets air in at the same time..


for instance cylinder 1 and 4 works together.. when the cam spins it lets air into cyl 1 and 4.. now when it spins again.. does it hits the exhaust valve to open? than when it spins again it does the same for cyl 2 and 3?


kinda confused lol

 

ttt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by soon2bdropped &raquo;</TD></TR><TR><TD CLASS="quote">when the camshaft spin. the lobes hit the rocker arm to open the valve.. does all 4 cylinder gets air in at the same time..</TD></TR></TABLE>

Think about this. If all 4 cylinders got air at the same time and fired at the same time, the engine would jerk once every 2 revolutions. Does your engine run like this or is it smooth?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">for instance cylinder 1 and 4 works together.. when the cam spins it lets air into cyl 1 and 4.. now when it spins again.. does it hits the exhaust valve to open? than when it spins again it does the same for cyl 2 and 3?</TD></TR></TABLE>

Just because cyl 1 and 4 move together, doesn't mean that they are on the same cycle. When cyl 1 is getting air, cyl 4 is firing (both moving down). On the up stroke, cyl 2 is compressing while cyl 3 is getting rid of gasses. The cylinder numbers depend on the firing order, which I don't know off the top of my head, but that's the general idea: the cylinders alternate, and a cylinder fires every 1/2 revolution of the crank.

 

hmm thats not how it shows on howstuffworks.com this single cam is messing up my theory. anyone else knows?

 

bump

 

anyone else know the theory behind all of this?

 

bump

 

Yes you have one camshaft, but that one camshaft have several lobes. Each cylinder has 4 valves. Each valve has its own lobe. 02 accord is correct. Re-read what he is saying. Firing order on most 4 cylinders is 1-3-4-2. Cylinder 1 fires, then 4, then 3,and then 2. Not a very good explanation, someone help this guy out.

 

all i need to know when cyl 1 fires what are the rest of the cylinders doing? just moving up and down until combustion for cyl 1 is made than moves on to the next cyl?

 

When cyl 1 is getting air, cyl 4 is firing (both moving down) , cyl 2 is compressing, cyl 3 is getting rid of gasses (both moving up).X2
( basic idea) Its not like they each go through the cycle independently. With each finishing 4 strokes before the next one begins its cycle. The cylinders work simultaneously and in conjunction to produce power.


It takes four strokes, 2 down and 2 up to make 1 power stroke per cylinder (4 stroke engine). So each cylinder is at different place in that sequence of 4 strokes, so there is a combustion stroke every 90 degrees I4 (in line 4 cylinder)gets 360(circle)/4=90 degrees. Think of the crank and the cam as circles. That's why more pistons makes the engine run smoother. V8 gets 360(Circle) /8= 45 so you get a power stroke every 45 degrees of crank rotation.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dognutz &raquo;</TD></TR><TR><TD CLASS="quote">It takes four strokes, 2 down and 2 up to make 1 power stroke per cylinder.....so there is a combustion stroke every 90 degrees I4 (in line 4 cylinder)gets 360(circle)/4=90 degrees.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dognutz &raquo;</TD></TR><TR><TD CLASS="quote">V8 gets 360(Circle) /8= 45 so you get a power stroke every 45 degrees of crank rotation.</TD></TR></TABLE>

You said it yourself: 4 strokes for each power stroke, and that equals 2 crank rotations (720 degrees and not 360).
Actually, it's once every 180 degrees for a 4 cyl and once every 90 degrees for a V8.

Here's a summary..............cylinders
crank position.............1.................2.......... ........3..............4
0 degrees..................firing......exhaust...... ..compression.......intake
180 degrees.............exhaust.....intake............ ...firing.........compression
360 degrees.............intake....compression........e xhaust.........firing
520 degrees.......compression.....firing.............. .intake...........exhaust
720 (2 rotations) it repeats, so 1 is firing again

Edited firing order and made graph easier to read


Modified by 02 accord at 4:05 PM 12/12/2006


Modified by 02 accord at 4:07 PM 12/12/2006

 

coo anymore theory?

 

What else do you want? That's all the theory there is.

 

I stand corrected. TY.

 

cool.. i understand..