........ roughly 720,000 litres, 720cubic metres....... roughly a freezer a 3rd the size of an olympic swimming pool. Too many variables for my liking so Im sticking with my roughly calc

 

1 litre per revolution; only one is on suck for the first half, three is on suck for the 2nd half.

Bearing in mind it's quite depressed in there, due to the small curtain area of the valves etc. So it's not 9,000 litres per minute.

 

Wouldn't it be 500cc per rpm/compression stroke?

 

1 litre per rev * 9000 = 9000 litres per minute. Or if 10% of it is fuel then I guess you could say 8100 litres per minute.

I don't know where you get 720,000 litres.

 

Don't forget 10% (assuming 10:1) is by mass rather than by volume.

Gary

 

Nick i thought that as well but
assume cyl 1 and 4 at TDC and 2& 3 at mid way
180 degrees makes cyl 1 fill and 4 empty
cyl 2 takes half a cylinder and 3 empties half
so thats 500 cc + 250 + 250 = 1 ltre for 180 rpm the next 180 degree does the same volume but its the 4 and 3 filling and 1 & 2 emptying

not used firing order just went in order

am i right?

 

If it takes 2 men an hour to dig a hole, how long does it take 5 men to dig half a hole?

 

Yes you do, they were making the obvious mistake of 9k rpm is somehow the amount of revs per second.

 

Right I got an answer, but I am not 100% sure it is right, in fact far from it because I have never calculated this before!

So I started off with petrol, which is by mass:-

86% Carbon
12% Hydrogen
2% Oxygen

These were somewhat made up, but they seemed realistic enough, they gave a HCV of 45.6kJ/Kg of fuel, which is fairly close to the standard for Petrol which is 47kJ/Kg. So notice first assumption!

Then did a wet gas analysis:-

O2 required to burn the fuel is 3.279Kg per Kg fuel
CO2 produced is 3.153kg per kg fuel
H2O produced is 1.08kg per kg fuel

This then gave a stoichiometric of 14.257:1. Bugger.

So I am well out I think, but by working out the volume per cylinder and the amount of the stoichiometric you could fit in the cylinder per revolution, I got 429.9cc + fuel.

If the cylinder is on its induction stroke every other revolution, this gives 429.9 x 75 which is 32,242cc. In sensible figures that is 32.245 tonnes of air required at 75rev/s. Quite frankly, I think that is ridiculous. But I thought I would share my failure with you all.

Good luck to the next person!

Graham
a sh1t engineer.

 

I have just noticed the 32.45 tonnes doesn't even line up with my stoichiometric, damn I really am bad tonight! If anyone is that interested, I could ask my thermo teacher to give me a hand tomorrow and I can come back with a definite answer?