An Intake Temp Cooling Idea

[mickq]

  Macktheknife said:

In short, it just wont work.

The total amount of "Refrigeration" available is negligable compared to the total amount of heat removed from the intercooler under normal operation. Even if you used 50 of them.

Far more to be gained from an increase in size of the IC or, for short bursts, a simple water spray directly on to the IC.

<{POST_SNAPBACK}>

There is no way a bunch of short water sprays will have the same cooling effect as a bunch of peltiers at -100 degrees.

Imagine piping your air through a hollow ice block...the air will get very cold. Ideally that's what it would be good to have your peltiers do to your intercooler. Sure its not going to happen (except in winter) but something between normal temp and "sh*t I just got an ice burn" would be nice for normal use.

Spraying water on an IC is just another way of doing a pretty primitive heat pump. The water absorbs some heat and either evapourates or gets blwon away with the heat in it.

A peltier is also a heat pump, but so efficient that it leaves the thing it takes the heat away from completely frozen. Try taking that much heat away with a water spray!

[mickq]

  NOS XR said:

I hear NOS may lower you intake temp and at no loss to you alternater, this is a good post but didn't anyone see the NX IC cooling kits? Carbon dioxide bottle with jets onto your IC and a cooling severe in your intake and a fuel rail with a inlet for Carbon dioxide.

Never heard of this type of set up, flick open a rice mag when you doing the weekly coles misson. Who know if they work?

<{POST_SNAPBACK}>

Yeah any gas, as someone mentioned, gets cold when you release it from a pressuried environment.

The main problem with gas is the ongoing cost. Fine if you have access to free gas, but sucks if you ave to pay and go through it quickly.

CO2 is a great idea as not only is it not flammable, but it also puts out fires.

You could hook it up so that when flooring it a quirt is done on the IC, and also an over-ride button that cools down the IC when you push it.

[mickq]

  mickq said:

  Macktheknife said:

In short, it just wont work.

The total amount of "Refrigeration" available is negligable compared to the total amount of heat removed from the intercooler under normal operation. Even if you used 50 of them.

Far more to be gained from an increase in size of the IC or, for short bursts, a simple water spray directly on to the IC.

<{POST_SNAPBACK}>

There is no way a bunch of short water sprays will have the same cooling effect as a bunch of peltiers at -100 degrees.

Imagine piping your air through a hollow ice block...the air will get very cold. Ideally that's what it would be good to have your peltiers do to your intercooler. Sure its not going to happen (except in winter) but something between normal temp and "sh*t I just got an ice burn" would be nice for normal use.

Spraying water on an IC is just another way of doing a pretty primitive heat pump. The water absorbs some heat and either evapourates or gets blwon away with the heat in it.

A peltier is also a heat pump, but so efficient that it leaves the thing it takes the heat away from completely frozen. Try taking that much heat away with a water spray!

(PS Water and metho works even better).

<{POST_SNAPBACK}>

[PozzE]

Well your right about one thing...

Some rally teams do use Peltier cooling, however unless they have a BAD accident the Peltier is nowhere near the intercooler. They use them to keep the drivers cool. A quick Google with the keywords, “Peltier rally car” found me the following page.

http://www.esa.int/esaCP/ESAWT68708D_Improving_0.html

ESA is the European Space Agency.

[turbotom]

The only realistic advantage the peltier devices may provide,as far as I can see, is to reduce the time for the IC to cool between runs at the strip.

As a means of cooling the IC core down prior to a short, sharp, high boost pass.

Any notion of being able to cool the IC with peltier devices whilst under boost, as in racing laps around a circuit, is simply dreaming. They do NOT have the thermal capacity to match the heat buildup generated from the intake (compressed) charge air.

Like I said, it would though, potentially be able to cool the IC quicker so that you can line up for another run at the strip a bit sooner.

(just my opinion)

tom

[bkofoed]

mickq - You're close with your understanding, but the load they place on the engine does dynamically change with the output load they are driving.

Alternators are complicated beasts- they are close to AC electric motors in that they have no fixed magnets. Instead they energise their own electromagnets to create the magnetic field.

What makes them different to AC motors is that the amount of energy put into the fixed coils (stator) is decided by a number of factors, primarily the difference between the target voltage for ideal charging and the system voltage of the battery with all accessories running.

It's the regulators job to set the power to stator coils. As the revs go up, the power to the stator coils goes down to maintain the same ouput voltage and current. (Regulators are IC's these days, and located at/near the alternator, not ECU)

If the electrical load on the battery increases, causing the system voltage to drop, the regulator allows more power into the stator coils to increase the output power of the alternator for the given revs.

The engine feels this as the loaded coils are harder to turn in a stronger electric field. This process of course can't go on indefinetly- the power the alternator can produce is a function of revs and the number of coil turns in the Stator (fixed) and Rotor (moving) coils. Thus alternators are rated at 55, 65, 80 etc Amps (at around 13.8v DC).

Ok so now consider the constant revs example. The ECU likes to keep idle in a tight range, regardless of load (excusing AC which on some cars triggers high-idle). So how do we keep the revs the same and produce more current for say high beams plus Cro's stadium lights? Free power? nope.

Well, the Alternator senses the greater load (as a voltage drop across the electrical system) and cranks up current to the stator. The stator in turn provides increased work (mechanical load) to the engine. The engine notices the idle start to drop, and so whacks in more fuel.

The whole system will self-govern and the end result is the injectors fire in more fuel per minute, the idle revs remains the same, and the alternator produces more current.

A neat outcome of all this is that we have perfect conditions to drive the Alternator warning light. It is illuminated by the differecnce in voltages between the Baterry and the Alternator output.

So when the engine is at rest, the light is on (12 bat - 0 alt = 12 v at light)

When the battery is nearly stuffed and wont charge, we have (10 bat - 12 = -2 v at light) we have a partially lit Alternator light. If the idle is too low, you may also get a partially lit indicator light (12v bat - 10v alt = 2 at light)- often blipping the revs cures this one as the alternator is albe ot make more power at higher revs.

You may also have heard belt squeal on older cars after starting - this is often slipping of the belt on the alternator pully, when the alternator is trying it's hardest to recharge the battery after cranking. It won't happen when the bat is charged and the car warmed up as the alternator load on the engine drops to almost insignificant.

Incidentally, changing alternator pulley sizes to reduce rotation speed can often be pointless, as the regulator will just shove more current into the staor coils increase power output for those revs. It is useful however if the rev limit has been increased and you want to reduce accessory drag at higher rpm.

Easy eh?

more reading - http://www.alternatorparts.com/understanding_alternators.htm

Sorry was meant to be a short reply, but meh.

BK

[bkofoed]

Sorry took too long proof reading - to continue

So the change in pulley size causes the reg to put more power to the stator coils, which will present almost exactly the same load on the engine as it did before the pulley change! If you're lucky (thick?) and went for a HUGE pulley to drop RPM, you may even lose the abillity to charge at idle altogether!!

PS - I like electronics too.

I do feel a peltier setup is not efficient enough (yet) to cool the intake charge or intercooler while driving and be practical.

Here's why.

At the lights, we have radiant heat hitting the intercooler (from radiator, etc, hot engine air), plus all the stored heat in the pipeworks and turbo housing, and the intercooler is already radiating away as much as it can (assuming no airflow). This is all happening when stock.

The peltier can extract the heat, but as it is a pure heat pump, it shoves it to the hot side, and then what? We need BIGGER area of heatsink, bigger than the whole IC core, to get rid of the heat faster than the core was doing already.

Yes, I accept that we can push more heat onto a heatsink (say a few hundred degress) with the peltier and therefore develop a greater ratio of heat transfer due to the delta with ambient temp, but we are still talking about something BIG.

Ofcourse we could water-cool the peltier hot side, but then why not just water-cool the intake charge with water to air intercooler anyway???

Now, consider those used on PC's - the peltiers are in the order of 80 - 100 W and cool the tiny die which dissipates 50-70W as heat. Our intercooler is rated at several KILOWATTS of cooling - that means a lot of Peltiers drawing a lot of power needed, causing more fuel burn, heating the cooling water, producing more radiant heat out of the radiator core!

As someone said above, they could be used to accelerate the cooling process at idle quite well I'm sure.

However the amount of cooling needed to maintain peak boost at even part-throttle up a hill for a few seconds and keep charge temps down is probably far too high for peltier technology today. Water to air already handles this well.

What if we took those 300+ watts you're talking about for peltier and used them drive more Radiator fans? Stock ones I'd guess run at about 100-150W, so we'd be roughly talking twice the airflow- wouldn't that be something? Mega fans - ON - mega fans OFF

Later.

BK

Edited 07/12/05 02:53 AM by bkofoed

[NT TURBO]

There is a lengthy reply above but I'll just add I hope no one beleive's you can generate electricity without mechanical work, the more current you draw the higher the mechanical load of the alternator on the motor. As Vik says no free lunches.

I had a high powered linear amp for my CB in my younger days, would easily stall the motor unless it was revving.

And 350W, if that's power consumption(not cooling output) at 12V you're talking 30 amps per unit.

[Paranormal]

Just a thought, every one seams to be speculating about placement mostly on to IC .

How about encasing both the after airbox hose and the after turbo hose, with a larger hose say 1 inch diameter larger (material maybe steel would be better) and filling the space between the hoses with say radiator coolant so it wont frezze, then attaching peltiers to the outside of both the pipes.

As some one previously posted it would then be like your air intake going thru a ice cave, hmm also why not instal a fuel surge tank with a peltier, and um you know how they market them sh*tty what are they called um eclone?? them silly vein things that supposededly give you more horespower etc, well a couple inserted into the above tubes would circulate the air in a aircraft turbine sort of flow, thru the ice tubes???

Ah just a thought, back to my beer, see yas.

[Paranormal]

Actually it would have to look pretty cool if you opened ya bonnet at the drags with all steel intake tubes covered in a 1/4inch thick ice like a pub beer tap, but hey you might need an invertor and 500 peltiers, then again just flow beer thru em whilst your waiting for the start, install an external beer tap for pit crew , the more they drink the colder the intake pipes.