2014 intercooling

[timbo]

The pistons are a compressor. Agree?
So the rule applies in the same way. Intercool between compressor stages.

Got it, so that way the conclusions from the article are still valid.

It's a misconception that having an intercooler is bad, or a waste of time.

I didn't say it was bad. It is definitely good if you run a lean mixture. It is definitely good if you reach knock conditions and can avoid them with intercooler.
But I question how much it adds (if anything) if you have a set amount of fuel to burn and combustion process is not a problem.

What you do to improve efficiency is scale back that power to the same level as the non intercooler setup and you realize that you will have gains.

I still don't understand what you mean here.

For every compressor stage, try to reduce temperatures. It always helps. Increased Mass flow with the same work is what you want. in fact it is this same density reason as to why engines lose so much power in brasil on for those hill climb cars.

It's about pressures, not temps there.

And wuzak mentioned preheating with the gas turbine. If i remember correct, Honda did this with their ra168 engine. But instead of reheating the air,which would be a negative effect, they preheated the fuel instead. I'm not sure what effect that has but it was positive.

Intercoolers are very costly for gas turbines, and that's because they are water cooled and quite huge. But sometimes the price is very much worth it. Reheat with intercooling gives efficiency gains, no question about it.

As far as turbines go, it is all in the article. Intercooling=bad, intercooling+ reheating=good.

But we don't have to argue this really, we've seen modern cars with direct injection using intercoolers. And if they weren't necessary makes like BMW wouldn't invest so much aerodynamics and packaging know how to place these things in their cars. Even going as far as to have water to air cooling.

Before we know what conditions they are run I don't think there's much to discuss.

[RicerDude]

A mini intercooler just behind the driver's head or between the fuel tank partially in the path of the intake flow could make sense. Coolant from the traditional radiator system could be shared with the liquid to air intercooler perhaps with all coolant filter in through the intercooler first prior to entering the engine.

I just cannot forsee these massive air to air units we've seen conjectured in early renderings taking up an entire sidepod making sense. One sidepod for an intercooler, and the other for a traditional radiator? I can't see it.

I was thinking with the lack of a large airbox taking up space high up in the engine bay and a much smaller fuel tank next year your idea might be a pretty good solution so I came up with this drawing...
Picture isn't working so here's a link...

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The intercooler is mounted the other way around and tilted like it would be in the sidepod. Also the intercooler will flange out as is gets deeper into the engine bay so you could get away with just the one.
the ducting will be channelled around the turbo inlet in a similar way to this...

[Ferraripilot]

That's an interesting concept, I like it. I suppose the MGU-H could be mounted directly under the turbo which I believe Ferrari are doing, and the coolant feeds to the intercooler would be somehow piped in, seems simple enough.

[wuzak]

That's an interesting concept, I like it. I suppose the MGU-H could be mounted directly under the turbo which I believe Ferrari are doing, and the coolant feeds to the intercooler would be somehow piped in, seems simple enough.

The animations that we have seen show an MGU-H in teh vee - like Renault's.

The only indication we have that the MGU-H will be under the turbo is a rough sketch.

[ringo]

It's about pressures, not temps there.

Nope, they are very much tied together. You are aware of Boyle's gas law and Charles gas Law?

Timbo, to simplify the discussion, lets ignore the intercooler. Since all it does is reduce intake air temperture, lets look on that instead.
If i have an engine breathing in 40 degree air and another engine breathing in 25 degree air. Both are naturally aspirated.
Which one would make more power? And what would have to be done to have equal horsepower from both engines?

The one breathing in the lower temperature air has a greater air mass flow and must supply a matching increase in fuel to burn that air. Below i have power output for a 1.6lt engine at 15000 rpm. flame temperature and pressure are given along with air mass flow.

40 degrees: 332 hp, 3308*, 133.859 bar, air mass flow, 0.25586 kg/s
25 degrees: 351 hp, 3282*, 139.449 bar, air mass flow 0.27163 kg/s

Now clearly colder is better, but since we are burning stoichiometric, more fuel will be needed for more air, so it's hard to argue fuel efficiency.

Now one has a 19hp advantage. What if we make the fuel flow equal?
Since this engine is not turbo charged, i have to vary something. I can vary the compression ratio or the engine speed.
Varying engine speed to give the same air mass flow:

Engine speed is reduced to 14,129 rpm from 15,000rpm. The power output is the same and everything else as above.

We understand that at the end of the day it's the completeness of fuel combustion that decides the efficiency and the compression ratio. But this ignores other things like the mechanical aspects and the chemical aspects.

You mentioned temperature which is also true, however the temperature is tied into pressure and density. Note how the flame pressure is increased when the temperature decreases.

The intercooler has effectively allowed the engine to do less rotations to produce the same power; and same thermal efficiency. However your overall efficiency will be improved, since mechanical losses will be reduced.

Saying all that, i think there is something interesting in this, as i have realized that the fuel flow limit as a function of RPM caffects things... I just noticed something..

[ringo]

If up to 10,500 rpm the flow is a function of rpm. And an intercooled engine has to spin slower to keep the same mass flow assuming stoichometry..
Then there is a problem. It cannot do this if it is to observe the flow limits as a function of speed. Both engines must give the same fuel flow with the same speed.
The intercooled engine would have to simply run at a reduced displacement, or a reduced compression ratio. The latter is not the best option as it affects efficiency directly.

At a reduced displacement, the engine size would be 1502 cc instead of 1595 cc. for the example above.

What does this say? Still a positive mechanically to work with an intercooled engine. It's just the aero part...

You know with direct injection (i'm not sure of the detonation effects with it), but assuming it can be ignored. Thanks to the fuel limit regulation with regards to engine speed before 10,500rpm, Running without an intercooler is plausible if detonation is not an issue. You can throw 100 degree air in the engine and just bump up the engine speed correspondingly.

That fuel limit equation in the regs is ironically hampering efficiency. hahaha.

[timbo]

Nope, they are very much tied together. You are aware of Boyle's gas law and Charles gas Law?

C'mon, we are talking Earth atmosphere here. You don't see people complaining about power drop in Bahrein, but you do at Interlagos! It IS about pressures.

The one breathing in the lower temperature air has a greater air mass flow and must supply a matching increase in fuel to burn that air. Below i have power output for a 1.6lt engine at 15000 rpm. flame temperature and pressure are given along with air mass flow.

40 degrees: 332 hp, 3308*, 133.859 bar, air mass flow, 0.25586 kg/s
25 degrees: 351 hp, 3282*, 139.449 bar, air mass flow 0.27163 kg/s

Now clearly colder is better, but since we are burning stoichiometric, more fuel will be needed for more air, so it's hard to argue fuel efficiency.

Now one has a 19hp advantage. What if we make the fuel flow equal?

Yep, you have to adjust to the same FUEL flow, not air flow.

You mentioned temperature which is also true, however the temperature is tied into pressure and density. Note how the flame pressure is increased when the temperature decreases.

The thermal efficiency is ONLY dependent on temperatures. You can recalculate it into pressures, or volumes, in fact pure Otto-cycle engine efficiency can be expressed thru compression ratio. However, real life performance may depend on many other things.

The intercooler has effectively allowed the engine to do less rotations to produce the same power; and same thermal efficiency. However your overall efficiency will be improved, since mechanical losses will be reduced.

Saying all that, i think there is something interesting in this, as i have realized that the fuel flow limit as a function of RPM caffects things... I just noticed something..

Fuel flow limit changes things VERY much.

[langwadt]

Nope, they are very much tied together. You are aware of Boyle's gas law and Charles gas Law?

C'mon, we are talking Earth atmosphere here. You don't see people complaining about power drop in Bahrein, but you do at Interlagos! It IS about pressures.

The one breathing in the lower temperature air has a greater air mass flow and must supply a matching increase in fuel to burn that air. Below i have power output for a 1.6lt engine at 15000 rpm. flame temperature and pressure are given along with air mass flow.

40 degrees: 332 hp, 3308*, 133.859 bar, air mass flow, 0.25586 kg/s
25 degrees: 351 hp, 3282*, 139.449 bar, air mass flow 0.27163 kg/s

Now clearly colder is better, but since we are burning stoichiometric, more fuel will be needed for more air, so it's hard to argue fuel efficiency.

Now one has a 19hp advantage. What if we make the fuel flow equal?

Yep, you have to adjust to the same FUEL flow, not air flow.

You mentioned temperature which is also true, however the temperature is tied into pressure and density. Note how the flame pressure is increased when the temperature decreases.

The thermal efficiency is ONLY dependent on temperatures. You can recalculate it into pressures, or volumes, in fact pure Otto-cycle engine efficiency can be expressed thru compression ratio. However, real life performance may depend on many other things.

The intercooler has effectively allowed the engine to do less rotations to produce the same power; and same thermal efficiency. However your overall efficiency will be improved, since mechanical losses will be reduced.

Saying all that, i think there is something interesting in this, as i have realized that the fuel flow limit as a function of RPM caffects things... I just noticed something..

Fuel flow limit changes things VERY much.

indeed, it is no longer a matter of squeezing as much oxygen in to the cylinder, adding fuel to match to get maximum power. Now there's a fixed amount of fuel and you need to add the right amount of oxygen.

Hot high pressure air, or cold lower pressure air can give you the same amount of oxygen. If the intake air is already at
high pressure you don't need as high a compression ratio so I guess you might end up with the similar pressures and temperatures in the cylinder just before ignition, it is just a mater of whether some of the compression takes place in the cylinder or in the compressor
The lower compression might be a disadvantage in the power stroke? maybe it will just add more power to the turbine?

I'm sure all the numbers have been crunched and the manufacturers came up with what they think is optimum

[turbof1]

indeed, it is no longer a matter of squeezing as much oxygen in to the cylinder, adding fuel to match to get maximum power. Now there's a fixed amount of fuel and you need to add the right amount of oxygen.

I suspect that new fuel will be engineered which can handle the extra oxygen chemical reaction.

C'mon, we are talking Earth atmosphere here. You don't see people complaining about power drop in Bahrein, but you do at Interlagos! It IS about pressures.

The turbo turbine itself is about pressure, the intercooler is not. I don't know if this is a good or correct way to explain it, but turbo atmosphere isn't the same as earth atmosphere. It is a micro atmosphere on its own, with a huge amount of heat. gasses expand under heat, so does oxygen. Imagine, and don't try, that you are heating up a pressurized oxygen tank. The oxygen will want to expand under the increasing heat, until the tank can't take no more and explodes.

The intercooler is there to significantly increase density of oxygen.

[timbo]

The intercooler is there to significantly increase density of oxygen.

Yes, at nearly constant pressure. But the idea is to get as much mass into cylinder as possible, because in normal situation you can burn as much fuel as you want. Even more, at high boost you would want to run mixture rich to avoid detonation and provide cooling. So intercooler allows to burn more fuel. But with limit on fuel flow the benefits of intercooler might not be so clear cut.

[turbof1]

The intercooler is there to significantly increase density of oxygen.

Yes, at nearly constant pressure. But the idea is to get as much mass into cylinder as possible, because in normal situation you can burn as much fuel as you want. Even more, at high boost you would want to run mixture rich to avoid detonation and provide cooling. So intercooler allows to burn more fuel. But with limit on fuel flow the benefits of intercooler might not be so clear cut.

Again, the teams and engine manufacturer will try to change the combustion of the fuel to make it more suitable for the pressurized and more dense air. Maybe not per se to get more power out of it, but more efficiency, more lenient towards a higher optimal oxgygen/fuel ratio combustion. I think with the fuel flow limit and fuel lmit teams will be aiming more for this.

My take on it is that the cooler, more dense air in the cilinder is more easily to "heat up" and make it more rapidly expand there, for the same fuel. That'll indeed generate more heat at high boost, but remember the turbo can only run 125,000 rpm, so there is an upper limit to the total heat at a given moment. The biggest part to remember is that the turbo will be spooled. It'll run near or perhaps even constantly at 125,000 rpm at all times. That does make life easier to correctly ignite the mixture.

Detonation would be dependent again on how the fuel is engineered, how the engine is build, and of course the cooling itself. But the latter is more an aerodynamic concern, not a power unit concern.

[langwadt]

The intercooler is there to significantly increase density of oxygen.

Yes, at nearly constant pressure. But the idea is to get as much mass into cylinder as possible, because in normal situation you can burn as much fuel as you want. Even more, at high boost you would want to run mixture rich to avoid detonation and provide cooling. So intercooler allows to burn more fuel. But with limit on fuel flow the benefits of intercooler might not be so clear cut.

Again, the teams and engine manufacturer will try to change the combustion of the fuel to make it more suitable for the pressurized and more dense air. Maybe not per se to get more power out of it, but more efficiency, more lenient towards a higher optimal oxgygen/fuel ratio combustion. I think with the fuel flow limit and fuel lmit teams will be aiming more for this.

My take on it is that the cooler, more dense air in the cilinder is more easily to "heat up" and make it more rapidly expand there, for the same fuel. That'll indeed generate more heat at high boost, but remember the turbo can only run 125,000 rpm, so there is an upper limit to the total heat at a given moment. The biggest part to remember is that the turbo will be spooled. It'll run near or perhaps even constantly at 125,000 rpm at all times. That does make life easier to correctly ignite the mixture.

Detonation would be dependent again on how the fuel is engineered, how the engine is build, and of course the cooling itself. But the latter is more an aerodynamic concern, not a power unit concern.

you need X number of oxygen molecules, high pressure hot air or low pressure cold air can supply that, with high pressure
you need less compression ratio to reach the same pressure before ignition that would also add less heat. I am not sure it would be so different

The 125000rpm limit is for the mgu-h, you can gear it

[turbof1]

The 125000rpm limit is for the mgu-h, you can gear it

Which limits in turn the turbo:

Instead of a wastegate, the turbine within the turbo is fitted with a generator. Normally, as the engine rpm increases, more exhaust gases are created and therefore the turbo spins faster. Traditionally, a wastegate valve is used to bleed off excess exhaust gases to prevent the turbo from over-speeding. However the generator recovers more energy as rpm increases, acting as a resistant force to the oncoming exhaust gases and preventing over-speeding.

This resistance allows the turbo to reach a maximum limit of 125,000rpm at maximum fuel flow rate without over-speeding.

you need X number of oxygen molecules, high pressure hot air or low pressure cold air can supply that, with high pressure
you need less compression ratio to reach the same pressure before ignition that would also add less heat. I am not sure it would be so different

The clue here is that teams want a combination of both: high pressure cool air. Both pressure and temperature influence mass density (how close the oxygen molecules are to eachother). This makes a bigger expansion inside the cilinder.
The trick will be to design a fuel that can react correctly with the oxygen molecules, aka the stoichometric combustion.

[timbo]

The clue here is that teams want a combination of both: high pressure cool air. Both pressure and temperature influence mass density (how close the oxygen molecules are to eachother). This makes a bigger expansion inside the cilinder.
The trick will be to design a fuel that can react correctly with the oxygen molecules, aka the stoichometric combustion.

Not sure what you mean here. For a given mass of fuel you need a defined mass of air. The trick is to get enough air to fully burn the fuel. There seems to be no limit for boost pressure, so you would either have higher boost and no intercooling or lower boost and intercooling.

[turbof1]

It's about the amount of oxygen atoms you can get into the chemical reaction - fuel is a structure of multiple different atoms which all react differently with the oxygen atoms. Finding a better molecule structure of fuel lets you have the same reaction with less fuel. Inefficient fuel requires more mass in fuel then more efficient fuel. I'm not sure if pressure influences the reaction and thus changes the optimal molecule structure, I'm no chemist, but if it does you need to redesign fuel.