ok, the reason i brought you here was, i'm going to school to be a diesel technician myself and i just got started a few months ago, but anyways, my instructor assigned the class an assignment, there's two questions. i think i have the right answers but i want to see if i'm right and if you can help me out if i'm wrong.

QUESTION 1: if an engine's crankshaft is turning 2000 RPM then how long (in literal time, or clock time, not the degrees to crank rotation) would the intake valve be open for?

QUESTION 2: with the same scenerio described above. how many times would fuel be injected into one cylinder?

ok, i'm gonna post my answers above, (or below depending on how you have your CP set up) but anyway, i'll post them so you don't think i'm lying and i just want the answers. trust me guys, i really did sit down and think about this...

 

QUESTION 1: intake valve is open for 0.12/sec. at 2000 RPM b/c the cam is half of crank rotation and valves are half of cam speed. so the intake would therefore open 500 times every 60 seconds and 60/500=0.12/sec.

QUESTION 2: 12 times per second

 

At 2000 rpm a 4 stroke motor would eat fuel 1000 times. one rev is two strokes. so it takes two revs to get fuel. so you get 2000 rpms div by 2 and its 1000 times a min. or 16.66666..... times a sec

 

It only gets fuel on one of those 4 strokes so wouldn't it be 500 times? Intake, Compression, Power, Exhaust. and it only gets fuel on the power stroke. and that would be 8.3333....times a sec

 

ok, can you tell me how you got 16.6 times a sec.

and ya, sorry i forgot everyone, it is indeed a 4 cycle engine.

 

i got that same number before the above answers, but that was for how long the intake valve was open, and i knew that was waaayyyy tooo long.

 

1000 rpm divided by 60 secs in a minute

 

well you need to remember at 2000 rpm a engine does 4000 strokes a min so that gives you 1000 intakes a min 1000 intakes a min is 16.66667

 

i think your right, but now what about question 1. but your answer seems to make the most sense. because like i said earlier, cam is half of crank and valve/injector would be half of cam. in my state of mind anyways.

 

Ah, ok gotcha. Didn't even think of that.

 

ok, that is correct, so indeed the number of times a valve opens is = to cam speed. am i right on this

 

i knew that in the back of my mind but i just kinda neglected it.

 

QUESTION 1: 0.06 of a second

QUESTION 2: 16.7 times a second

 

1) 0.06 seconds

where in the heck is HOHN when you need him?!?!?!

 

and at any thing over 2 rpms the intake is open for 15 seconds a min

it should be that since at 2 rpms its 4 strokes a min
and at 2000 rpm its 4000 strokes a min intake is open for 1/4 the stroke rate
so you have 1000 intake events a min for 16.6667 intake events a sec. one sec divided by 16.66667 eqals .059 secs of intake duration giving a cam that is open for the entire intake stroke of the engine