Turbo intercoolers - purpose?

No, they are not classed as fuel once combined!?!. Your definitions are slightly out of whack - they don't conform to the normal fuel/oxidiser definition.

Really? Now there's a novelty.

Well I suppose Ozone comes from somewhere but it's labouring the point

i'm going to fit an intercooler to my pressure cooker :) opened it last nightm used it for the first time let's just say i won't be doing that again :)

I was always taught that you need oxygen to make stuff burn I can't quite remember that triangle thing where you have 3 things and if one of them is removed hen the fire will go out but I think it's a fuel source, air and heat take away the fuel and no matter how hot it get's there is nothing for it to burn in take away the air and there is nothing again for the fuel to mix with and take away the heat and the fire goes out again

I know there are exception to this rule but it's just the basics

why else does the space shuttle have big oxygen tanks and fuel tanks? the oxygen is used to burn the fuel and with out it you just get a nice little flash as the fuel uses up all the oxygen in the surrounding area

For the little people inside to breathe of course ! :)

That's correct - remove any one of the three, and the fire stops.

Hi Kenny, I know this is a bit late in the piece, but I am the Queen of USENET so I can do what I like.

It is difficult to predict what will happen to the mass flow rate at the inlet. The intercooler (yes it is really a misnomer) may well introduce an

*increase* in "back pressure" because of skin friction between the airflow and the large surface area of the intercooler.

If the mass flow rate measured by the meter does not change, there will be no change in the mass flow rate of fuel either (assuming this is how the FI system calculates fuelling). If nothing else is changed (i.e. ignition timing, compression ratio etc.) then the engine may make more net flywheel bhp by virtue of lower average combustion chamber temperatures losing less heat to the cooling system.

If the mass flow rate does increase at the inlet, it's because the inlet tract as a *whole* is able to flow more air with the intercooler than without. This would probably be because the turbo is doing more work on the inlet airflow (this means that it is putting energy into the inlet airflow at a higher rate than it was without the intercooler, because "back pressure" has been reduced).

I hope this makes sense! There are a lot of "this because of that because of this" because (d'oh!) the inlet tract is a long string of pressure-volume-density-speed change events occurring in the airflow as it goes along the tract.

Yes, the inlet does "know" what is happening downstream because the "information" is transmitted up and down the airstream in the form of pressure waves (sound).

Compressible flow is a bit of a nightmare to predict mathematically, which is why so much money is spent on wind tunnels, and models covered in little surface pressure measuring devices so we can find out what really is happening!

Hope this helps, I think you can hang on to your fiver anyway. Please don't start "Spidering" me, I am an aeronautical *structural* engineer, my knowledge of compressible flow and thermodynamics is a bit rusty!

Cheers

Rachael

Wow - very comprehensive answer Rachael, thanks!

I knew there was a lot more to it than simply "colder = denser = more". So often on usenet self-proclaimed "experts" will simply repeat what they've read elsewhere, without actually thinking through the implications.

Ah! I used to an aeronautical *mechanical* engineer - stresses and strains I have no problem with, but thermodynamics was always a no-no!

In message , Kenny writes

I hope you are not referring to the other posters here who answered your query and were simply trying to help.

I'm sure he isn't, please don't start another "Spider special" on my account! I think Kenny's been reading the alt.autos.audi group too much.

Rach

Of course not! Not even the chap who said oxygen was a fuel ;-)

But what's the point of trying to answer a question you don't know the answer to, even if you *are* trying to help?

"Kenny" mumbled:

Because we enjoy it.