Heat at Air Intake

[littlefarny]

Hi guys, not a whacky idea this time, I promise

Exhaust gasses and intake gasses are normally quite hot due to all of their movement through the various systems they go through (including combustion!), and as density changes at an almost inverse exponential rate against temperature, is it a good thing they're warm?

Sure the increased pressure might be good, but is the decreased density good for combustion?

Would it be possible to pass the exhaust from a turbo for example through a water/oil coolant system to make sure that it doesn't get too hot?

Air in >> Combustion >> Exhaust >> Turbo >> Coolant System >> Air System

Of course there would need to be some regulation to make sure too much kinetic energy isn't robbed, but is this just too much effort for too small a gain? Is it even viable in the first place?

Thoughts please!

[GORDON STREETER]

WTF are you on about. explanation please ? Cooling the exhaust gasses "after" the turbo I can't see what that would do, as for the induction that's why sodding great air/water inter coolers are made !

[Adam43]

Unless this is some sort of EGR* system, why would you do that?

*Exhuast Gas Recirculation, which can be used to reduce emissions.

[tristancliffe]

For best exhaust performance you want to keep the heat in the exhaust - look at F1 and Top Fuel cars - they do NOT lag their exhaust pipes. There might be a tiny benefit in lagging a closed wheel car as it MIGHT reduce the under bonnet temperatures sufficiently to give another horsepower or two, but I'm not a believer.

Exhausts scavenge better with higher temperatures. Lagging also increases the chances of the exhaust material becoming too hot and it softening/deforming.

[terence bower]

Which is exactly the reason we stopped lagging Manifolds years ago,got pee'd off with having to keep welding them up again!!

[GORDON STREETER]

I see from your profile that you are at Brunel University(or was) studying "Motorsport Engineering" . Looks like you've been studying the Beano !!, but I'll give you the benefit of the doubt if you can explain what you mean .

[Adam43]

Originally Posted by tristancliffe

For best exhaust performance you want to keep the heat in the exhaust - look at F1 and Top Fuel cars - they do NOT lag their exhaust pipes. There might be a tiny benefit in lagging a closed wheel car as it MIGHT reduce the under bonnet temperatures sufficiently to give another horsepower or two, but I'm not a believer.

Exhausts scavenge better with higher temperatures. Lagging also increases the chances of the exhaust material becoming too hot and it softening/deforming.

As this might be an interesting topic in its own right I've split them out to a new thread: http://www.ten-tenths.com/forum/showthread.php?t=111706

[littlefarny]

Originally Posted by GORDON STREETER

I see from your profile that you are at Brunel University(or was) studying "Motorsport Engineering" . Looks like you've been studying the Beano !!, but I'll give you the benefit of the doubt if you can explain what you mean .

Wow. I didn't think making a post whereby the point was to see whether an idea was possible would get me insulted just because it essentially isn't possible/not needed (besides, the Brunel course is actually a Mechanical Engineering course with very little car-based content). I don't claim to know a lot about proper racecar engineering - that's why I'm studying.

The concept is based upon what was stated before as an EGR system whereby the exhaust gasses were passed through the turbo (or more likely a supercharger), cooled and used in the combustion process again. My question was whether if the reused exhaust gasses were then further cooled whether that would generate more power or less.

[AU N EGL]

You could wrap your air intake pipes, with a small copper pipe and run compressed CO2 or freon ( as Air Con ) though the copper pipe too dramatically cool the air intake pipes and lower the air temp going into the manifold.

[littlefarny]

Originally Posted by AU N EGL

You could wrap your air intake pipes, with a small copper pipe and run compressed CO2 or freon ( as Air Con ) though the copper pipe too dramatically cool the air intake pipes and lower the air temp going into the manifold.

That's the kind of set-up I was thinking of. But of course the added weight of the compression system and tubing would probably negate any benefit (if there were any to be had).

[Dave Brand]

Originally Posted by littlefarny

The concept is based upon what was stated before as an EGR system whereby the exhaust gasses were passed through the turbo (or more likely a supercharger), cooled and used in the combustion process again. My question was whether if the reused exhaust gasses were then further cooled whether that would generate more power or less.

An IC engine works by burning fuel. To burn fuel you need oxygen; in simple terms, the more oxygen you can get into the combustion chamber, the more fuel you can burn; not a lot of point, then, in using exhaust gases, most of the oxygen in which has already been used!

[Adam43]

Originally Posted by Dave Brand

An IC engine works by burning fuel. To burn fuel you need oxygen; in simple terms, the more oxygen you can get into the combustion chamber, the more fuel you can burn; not a lot of point, then, in using exhaust gases, most of the oxygen in which has already been used!

Which, oddly, you might want to do. For emission reasons. In an EGR engine you are trying to reduce the amount of oxygen to cut down on NOx production.

[littlefarny]

Does all of the oxygen get used in the cylinder though?
Say you have an air intake limit, would there be any benefit in running some of the exhaust gasses back through the combustion process at a cooled temperature so they essentially burn up all of the available oxygen, using the air that has already been taken in.

I apologise if this seems like a ridiculously stupid concept if it is, engines are by no means my strong or favourite point of motorsport (a lot more interested in composite and bodywork technology), and my knowledge is very limited by engineering standards.

[AU N EGL]

Originally Posted by littlefarny

That's the kind of set-up I was thinking of. But of course the added weight of the compression system and tubing would probably negate any benefit (if there were any to be had).

No. but may be illegal under your tech rules.

[Dave Brand]

Originally Posted by AdamAshmore

Which, oddly, you might want to do. For emission reasons. In an EGR engine you are trying to reduce the amount of oxygen to cut down on NOx production.

Point taken.

Originally Posted by littlefarny

burn up all of the available oxygen

Call me pedantic, but you don't burn oxygen. Burning is the process of combining flammable materials with oxygen! (See, I was listening in those chemistry lessons!)

Maybe you'd like to expand on your idea - are you actually proposing anything that isn't being done now, apart from cooling the exhaust gases?