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#51 munks

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Posted 03 February 2014 - 19:38

Newey going DIY style:

 

BfTSqkqCQAExS58.jpg

Has nothing to do with cooling. Clearly it's a USB port, hence the "platform computing" label just above it.



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#52 malbear

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Posted 04 February 2014 - 06:55

I knew this reminded me of something...proboscis monkey.

 

F1 has gone beyond absurd. Way beyond.

I think it looks exactly like the head of a  grain wevil



#53 MatsNorway

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Posted 09 February 2014 - 15:47

Could using a liquid to air intercooler reduce the size of the heat exchanger exposed to the air?

From 1.48..


Edited by MatsNorway, 09 February 2014 - 15:48.


#54 gruntguru

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Posted 10 February 2014 - 04:35

Another point is that intercooling to near ambient is probably not necessary.

 

1. The peak power available from the rules-restricted fuel flow can be achieved fairly easily from a turbo 1.6 so "warmish", less dense intake air is probably OK.

2. Thermal efficiency improves with increasing air temp (peaking at 70*C and above from Honda experience with the RA168E) and thermal efficiency equals power under the 2014 rules.

 

70*C intake air could be achieved using water from the engine cooling system and yes Wuzak, that would allow a reduction in heat exhanger area and cooling air flowrate.



#55 OnTheGas

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Posted 14 February 2014 - 02:47

The total cooling requirement should be substantially lower given that heat rejection = energy in - useful work done. Energy in (fuel) is less than 2013 and useful work done is similar.

Initially, when I read this statement, I was impressed because Andy Cowell, Managing Director of Mercedes AMG HPP recently said they now measure their overall engine performance by thermal efficiency (instead of hp, torque, etc).

 

Charge air cooling is included in the total heat rejection figure.

 

The reason they need more airflow (bigger sidepods) is the lower temperature they need to achieve in the cooled fluid (compressed air in the intercoolers). This leads to a smaller delta-T (air temp exiting sidepods minus air temp entering sidepods) and therefore a higher mass flow to achieve a given rate of heat rejection.

Right on both counts was my initial thoughts when I first read this. Thermal efficiency starts with the static energy contained in the fuel and subtracts the energy extracted as work.

 

The efficiency of extracting heat from the charged air via intercooler is less than extracting heat from the ICU via water and oil coolers because of higher deltas between ambient air versus heat in the oil and water from the engine.

 

For "energy in", presumably you also need to include (what I gather is) the higher input from regenerative braking this year?

 

No, that's only recycled energy that originally came from the fuel so, apart from inefficiencies in the storage/retrieval system, there is no heat generated.

OK...

 

The electric motors and batteries have much higher conversion efficiency than the ICE so much lower heat rejection. It is easier to look at the overall picture ie - total energy input for a race will be perhaps 20% less this year. Energy output as work will be similar, therefore:

 

2013.  100 units input = 25 units useful work + 75 units heat rejected

2014.    80 units input = 25 units useful work + 55 units heat rejected

Heat rejection reduced by (75-55)/75 = 27%

 

But then I read the interview by Auto Motor und Sport's Michael Schmidt of Andy Cowell, Managing Director at Brixworth where they are building the Mercedes power units. He said that while the old V8′s had a thermal efficiency of 30%, the target for the Mercedes PU106A Hybrid is to reach 40%. That is somewhat similar to what gruntguru is trying to explain here.

 

Then Andy Cowell said thet Mercedes PU106A Hybrid requires 20% more cooling than the V8′s. The classic oil and water coolers are smaller, the ones for the hybrid system bigger and with the inter-cooler there is a completely new element.

 

Given that the fuel has ~46MJ / kg, and significantly less of it will be used this season, why is significantly more cooling required?

 

On reflection I think I see the errors in the original statement of, "The total cooling requirement should be substantially lower given that heat rejection = energy in - useful work done":

 

That statement is true if the energy sources remained the same as last year, the petrol (which is reduced) and 60kw of power from braking. But instead we've new sources of energy...

  1. The power generated from braking is doubled to 120kw, and
  2. we are harvesting both electrical energy from a turbocharger and
  3. charging the intake air.

Three new sources of energy that was previously dissipated freely from the brake disks and exhausts respectively. For cooling purposes we had failed to account for these new energy sources.



#56 gruntguru

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Posted 15 February 2014 - 05:46

You nailed it On TheGas. Total heat rejection will be significantly lower, but much of that saving will be in the form of reduced heat loss to the brakes and exhaust and I failed to realise that fact. Apologies to you too Roger Graham - you were sniffing up the right track too.

 

Although items 1 and 2 are new sources of work, they only create a cooling requirement to the extent of their inefficiency - any braking or turbo-compounding energy that gets back to the wheels does not appear as heat. Item 3 is not a new source of energy - it is just an alternate form of engine cooling, reducing the heat rejected to the cooling water or exhaust.

 

So it is still simpler not to look for new sources of energy - rather perform an energy balance of the complete system which has only one energy source - the fuel (remembering of course to include changes in heat rejection to the brakes and exhaust)


Edited by gruntguru, 15 February 2014 - 06:14.


#57 MatsNorway

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Posted 15 February 2014 - 09:27

Their motors is got silly efficiency numbers. we are talking 99% if they want. But some might go less for weight purposes. They at least did that in the past.



#58 gruntguru

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Posted 17 February 2014 - 00:20

Yes the MGU's would have very high efficiency in both motor and generator modes. The inefficiencies seem to be in the battery charging and discharging. Does anyone know what the turn-around efficiency is for F1 electric KERS systems?



#59 Greg Locock

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Posted 17 February 2014 - 02:11

Usually the biggest inefficiency is the difference between the charging voltage and the discharge voltage for the battery, both of which are current dependent. For simple lead acid cells there is also the coulombic efficiency, 

 

here's a curve for a random LiPo battery, as you can see it charges at ~4.1 V, and discharges at ~3.8, giving a rough efficiency of 92%. This would drop at higher charge and discharge rates

 

http://www.ibt-power...lymer_tech.html

 

There are also losses in the electronics, but they are fairly small, say 1% loss for every step (not how it is worked out, basically an efficient design loses you 0.6V*current every time)

 

As a guideline the loop efficiency in a Prius is 60% which is why you don't generally charge the battery via the engine in order to use it in EV mode later.



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#60 gruntguru

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Posted 17 February 2014 - 03:58

A quick google shows some claims of up to 70% round-trip efficiency for both electric and flywheel systems, which sounds almost feasible given the 60% for Prius.

 

I also spotted a claim for 99% motor-mode efficiency for an MGU and only 93% in generator mode. Does this mean the MGU in question was optimised for motor-mode efficiency at the expense of generator-mode? If so I wonder why? The MGU turnaround efficiency of 92.07% (99% x 93%) is equivalent to 96% efficiency in each mode.



#61 Greg Locock

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Posted 17 February 2014 - 05:24

I find 99% is a bit suss. In order to achieve that you have to be very careful with windage and bearing losses, for the easy mechanical stuff, and then iron losses (don't use any iron or steel) and then the magnet design which is an easy few percent you can lose. Actually thinking about it all that stuff isn't very hard if you've got money and people.

 

I don't know why the efficiency would be different in M or G, maybe they were talking about typical efficiencies in use, when braking they should be aiming for max absorbable power rather than efficiency (even if the last bit of power you squeeze in is only 10% efficient it is still 'free') whereas in motor mode there is a tradeoff between power output and efficiency - the energy is no longer free. It's a waste of time asking me why exactly from an electrical standpoint, that is all I know, but the energy use tradeoff is an interesting one.

 

The motor controllers are very efficient, basically if you pay enough there is just one silicon junction in the power side, that's where the 0.6V comes from. The essential issue is that a MGU generates a voltage proportional to speed (whether turbo or wheel), whereas your battery is more or less a fixed voltage, so you need to match the two. The relatively cheap and cheerful way is a buck-boost circuit (I just buy them, to me they are just boxes with wires and knobs, I do not know what makes them go), which will turn any low DC voltage into a higher one, fairly efficiently. I use them with my solar power for the house to bump 12V from the old system up to 48V for the new system. In the solar car we used two systems, one to biff the output voltage of the panel up to battery bus voltage, and the other to reduce the bus voltage down to that needed for the wheel motor. Again the precise ins and out of why it is done that way was down to the smoke doctors. I can say that it is pretty impressive to run a 5 kW machine that needs no heat sinks or cooling (there was some ventilation for the batteries as they have an unfortunate thermal runaway effect).

 

I should add that I talk as if these things are DC, I suspect the motors are actually 3 phase switched DC with shaped pulses, which starts to look like an AC signal to me!


Edited by Greg Locock, 17 February 2014 - 05:29.


#62 RogerGraham

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Posted 17 February 2014 - 12:34

It doesn't explain the "why", but here's a snippet from Mr Newey today.  Roughly double the radiator surface area!  From http://www.autosport...t.php/id/112538

 

"The Renault seems to have a particularly large cooling requirement.

"Everybody of the three engine manufacturers will have a different target for how hot their charge air is going back into the plenum and Renault have given us a fairly challenging target.  It has all sorts of advantages if we can get there, but it is not easy to achieve."

 

Newey also admitted that the packaging demands of the new engines are an especially big challenge.

 

"It is certainly a challenge to package everything in," said Newey.

 

"The radiator area that we need to cool the charge air from the turbo and additionally all of the extra cooling we need for the electrical side of things, the batteries, the motor generator unit and so forth, the control box... It means that the radiator area is roughly double last year's car with the V8. So trying to package that in without compromising the aerodynamics too heavily is a challenge."



#63 gruntguru

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Posted 17 February 2014 - 22:53

I don't know why the efficiency would be different in M or G, maybe they were talking about typical efficiencies in use, when braking they should be aiming for max absorbable power rather than efficiency (even if the last bit of power you squeeze in is only 10% efficient it is still 'free') whereas in motor mode there is a tradeoff between power output and efficiency - the energy is no longer free. It's a waste of time asking me why exactly from an electrical standpoint, that is all I know, but the energy use tradeoff is an interesting one.

 

I wonder how the energy and power limits are defined in the rules? If the limits are defined as electrical energy or power sent to the motor it would be imperative to maximise the motor-mode efficiency. Perhaps that is what you meant by "free" and "no longer free".


Edited by gruntguru, 18 February 2014 - 04:44.


#64 Wuzak

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Posted 18 February 2014 - 01:40

I wonder how the energy and power limits are defined in the rules? If the limit is defined as electrical energy and power sent to the motor it would be imperative to maximise the motor-mode efficiency. Perhaps that is what you meant by "free" and "no longer free".


There is an efficiency factor built into the rules.

5.2.2 Energy flows, power and ES state of charge limits are defined in the energy flow diagram shown in Appendix 3 of these regulations.
When the car is on the track a lap will be measured on each successive crossing of the timing line, however, when entering the pits the lap will end, and the next one will begin, at the start of the pit lane (as defined in the F1 Sporting Regulations).
Electrical DC measurements will be used to verify that the energy and power requirements are being respected.
A fixed efficiency correction of 0.95 will be used to monitor the maximum MGU-K power.

 

I presume this means that you can send ~126kW electrically to the MGU-K, which will make 120kW at the efficiency factor. If you can get a higher efficiency from your MGU-K then you could get a small power gain.



#65 gruntguru

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Posted 18 February 2014 - 04:46

That explains it. So optimise your MGU for "M" and get 99% efficiency even if the "G" is compromised back to 93%.



#66 Wuzak

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Posted 18 February 2014 - 08:00

That explains it. So optimise your MGU for "M" and get 99% efficiency even if the "G" is compromised back to 93%.


But then you miss out on the generating side. The efficiency is for both directions.

As we have explored on RC, most tracks will be difficult to get 3/4 of the allowable recovered braking energy per lap (ie 2MJ). Some, liek Australia, are only able to get about half, and Silverstone looks like it will get less than 40% of the allowed energy. So losses in the G part of the MGU-K could be more significant than gains in the M side.

#67 Wuzak

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Posted 18 February 2014 - 08:33

I wonder if the efficiency differences between motor and generator operation is due to different operating speeds in each of the modes?



#68 alexbiker

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Posted 18 February 2014 - 17:27

That implies the unlimited load transfer from MGU-H to MGU-K will be critical on those tracks, and they'll be desperate to get everything out of MGU-K into the batteries they can without ruining the boost.

We could see huge power differences between different engines, different teams - aero efficiency, and software maps being different, and different phases of the race.  A last-stint charge on soft rubber in clear air with the wick turned up, versus a fuel-efficient time trial approach, against a first-third hero run.


Edited by alexbiker, 18 February 2014 - 17:29.


#69 gruntguru

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Posted 18 February 2014 - 23:47

I can't wait.

 

OTOH there is clearly potential here for one team to steal a technological "march" on the opposition and blitz the field for most of the season.



#70 OnTheGas

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Posted 20 February 2014 - 20:36

It doesn't explain the "why", but here's a snippet from Mr Newey today.  Roughly double the radiator surface area!  From http://www.autosport...t.php/id/112538

 

"The Renault seems to have a particularly large cooling requirement.

"Everybody of the three engine manufacturers will have a different target for how hot their charge air is going back into the plenum and Renault have given us a fairly challenging target.  It has all sorts of advantages if we can get there, but it is not easy to achieve."

 

Newey also admitted that the packaging demands of the new engines are an especially big challenge.

 

"It is certainly a challenge to package everything in," said Newey.

 

"The radiator area that we need to cool the charge air from the turbo and additionally all of the extra cooling we need for the electrical side of things, the batteries, the motor generator unit and so forth, the control box... It means that the radiator area is roughly double last year's car with the V8. So trying to package that in without compromising the aerodynamics too heavily is a challenge."

Pretty amazing information there...

 

How is Mercedes cooling the charged air for their PU106A? Are they using an air to air intercooler, or air to water?

 

  • The Ferrari uses an air to water intercooler.
  • The Renault uses an air to air intercooler.
  • I thought I heard Scarbs say on the Pit Stop Radio podcast earlier this week that Mercedes is air to water, but I'm not sure I've heard him correctly....


#71 alexbiker

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Posted 21 February 2014 - 16:20

Changing tack, with the rear brake-by wire, are we going to see harder braking this year?

 

Last year, when slowing from high speed the drivers jumped on the brakes as hard as possible, because the available force they could generate was insufficient to lock the front wheels with all the downforce.  They then feathered back as the car slowed.

 

This year, their leg force is driving two calipers instead of four - "The pressure in the rear braking circuit may be provided by a powered control system" - so that's a lot more pressure for the front calipers, with the balance maintained by the active system at the rear.



#72 RogerGraham

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Posted 23 February 2014 - 15:20

I read the text (in italics below) in a recent Autosport.com article.  What do TNFers make of the wording there with its emphasis on torque, in light of the infamous torque-versus-power thread?  

 

If I understood that thread correctly - and I wouldn't bet my house on that - shouldn't the article should be talking about optimal gear changes being about maximising average power?  Then relate the gear change behaviour to the broad power curve on these 2014 cars (100 kg/hour fuel flow limit etc)?

 

 

GEARSHIFTS IN STRANGE PLACES

There's a lot to get used to about the new sound of F1 engines for 2014. But it's not just the engine note, or the fact that the cars now have eight gears to go through as they brake and accelerate for corners.

 

If you listen carefully you will notice that the drivers no longer change gear at the same revs in each gear as they accelerate. The unique way these new engines deliver their power produces a torque curve that cannot simply be maximised by getting close to the rev limit before shifting up.

 

As far as the engine manufacturers are concerned, it is about changing gear at the right time, rather than at maximum revs. And the right time for second gear will be different compared to seventh, meaning upshifts aren't as evenly spread as we are used to.


Edited by RogerGraham, 23 February 2014 - 15:26.


#73 Henri Greuter

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Posted 23 February 2014 - 20:08

Nickname? 

 

 

 

 

p1gc.jpg

 

 

'Arapaima`

 

http://theaquariumwi.../Arapaima_gigas

 

Pity that Massa coudn't have his picture taken in it....

 

 

Henri



#74 MatsNorway

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Posted 24 February 2014 - 10:17

I think its really really cool to see both water to air and air to air being tried. The benefits of each is clearly not sorted out in total.

 

water to air intercooler has the following:

+ Better response

+ Better packaging

- More weight

 

+ Less surface area needed

+ Less drag

 

Might have:

+ Variable water flow to tune cooling temp to optimum Termal efficeny ( i still struggle to understand how anything but cool air is optimum for maximum hp at peak power but thats my problem)

- Might have more weight off the cars centerline giving increased tire wear.

 

air-air intercooler:

+ Is Lighter

+ No energy lost due to pumping loses due to no waterpump++

- No easy way to regulate intake air temp (it is what it is)

- Takes more volume

- More drag

 

It seems like they (the teams) are disagreeing on if water pumping loses gains back the loses by having less drag and better downforce potential by lean packaging.++

 

Thoughts?


Edited by MatsNorway, 24 February 2014 - 10:19.


#75 GreenMachine

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Posted 24 February 2014 - 11:40

You put the heat into the water, where does it go next?  There must be a transfer of that heat out of the system, or the coolant will soon be hotent ...



#76 MatsNorway

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Posted 24 February 2014 - 14:43

Short versjon. And heatsoak is a thing on water to air intercoolers yes. But its all about proper sizing.

Water%20to%20air%20intercooler1.jpg

http://www.enginebas...ntercooler.html


Edited by MatsNorway, 24 February 2014 - 14:47.


#77 GreenMachine

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Posted 24 February 2014 - 22:21

Thanks Mats for making my point so graphically.  The water then has to be cooled.  So the heat load to be dispersed is not reduced, just managed in a different way.

 

Is it only a packaging choice? As well as introducing two steps rather than one, you have two (different) inefficiencies at the points of heat transfer rather than one, which suggests that to overcome these losses you need MORE rather than less cooling capacity overall (certainly not less).  So any claim that using air-to-water followed by water-to-air charge cooling will make for better aero (reduced inlet area) is unfounded?   I am not sure if this claim has been made  here, but I have seen it somewhere.

 

Am I missing something here? 

 

As a by-the-way, I use an oil-water heat exchanger on my track car, and I am very conscious of the increased heat load placed on the radiator by this setup.  Because I am not Adrian Newey, I had sufficient unused capacity it seems, as I have not had a problem with water temperatures.



#78 OnTheGas

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Posted 24 February 2014 - 23:03

 

How is Mercedes cooling the charged air for their PU106A? Are they using an air to air intercooler, or air to water?

I've found the answer. Scarbs in his review of the E22 mentioned that the Mercedes PU106A does use an air to water intercooler.

 

I think its really really cool to see both water to air and air to air being tried. The benefits of each is clearly not sorted out in total...

Yes, it would be good to see some authoritative data on the advantages and disadvantages of each method.

 

Regarding the efficiencies in play for each method, the thought occurs that if we look at racing motors in karting and motorcycles, the increased power realized from water cooling of the motors versus air cooled motors indicates some efficiencies that may come in to play with cooling charged air with water vs air.


Edited by OnTheGas, 25 February 2014 - 00:03.


#79 Wuzak

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Posted 25 February 2014 - 01:41

Thanks Mats for making my point so graphically.  The water then has to be cooled.  So the heat load to be dispersed is not reduced, just managed in a different way.

 

Is it only a packaging choice? As well as introducing two steps rather than one, you have two (different) inefficiencies at the points of heat transfer rather than one, which suggests that to overcome these losses you need MORE rather than less cooling capacity overall (certainly not less).  So any claim that using air-to-water followed by water-to-air charge cooling will make for better aero (reduced inlet area) is unfounded?   I am not sure if this claim has been made  here, but I have seen it somewhere.

 

Am I missing something here? 

 

As a by-the-way, I use an oil-water heat exchanger on my track car, and I am very conscious of the increased heat load placed on the radiator by this setup.  Because I am not Adrian Newey, I had sufficient unused capacity it seems, as I have not had a problem with water temperatures.

 

The radiator for the water-air intercooler can be smaller than an air to air intercooler. The water can be circulated slower than the air would, which enables more heat transfer for a given area of cooler than air to air. 

 

Water can have multiple passes is a radiator without causing flow issues for the air. And water can have its flow rate altered to maintain the desired rate of cooling in the supercharged air.

 

The big disadvantage is, obviously, weight. It requires 2 radiators, a pump and a cooling fluid. 

 

Advantages include those mentioned and the ability to remote mount the radiator. The air flow path from the compressor to the intakes can be kept short while the radiator is mounted anywhere on the chassis.



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#80 gruntguru

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Posted 25 February 2014 - 06:55

+ Variable water flow to tune cooling temp to optimum Termal efficeny ( i still struggle to understand how anything but cool air is optimum for maximum hp at peak power but thats my problem)

The engines are capable of flowing sufficient air to make a lot more power than what they actually have. The power is limited by the fuel flow regulation. Running cooler intake air increases the air density so a greater mass of air (oxygen) is available. This is NO USE because there is insufficient fuel available to burn the extra oxygen.

 

OTOH, if the available fuel can be burned more efficiently, the engine will be able to make more power. Read the Honda RA168E paper and you will see that intake air temps around 70*C and above produce the best thermal efficiency. This will be particularly true for turbo compound engines because heat energy removed by the intercooler is less energy available in the exhaust. (ie the optimum intake temperature might be even higher than 70*C)

 

Note that these temperatures are high enough for the intercoolers to share the coolant used in the engine. This cuts down the number of radiators, coolant pumps etc. The higher temperature also means that the radiators can possibly be smaller and airflow lower than otherwise needed for low temperature intercooling.


Edited by gruntguru, 25 February 2014 - 07:03.


#81 GreenMachine

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Posted 25 February 2014 - 10:40

Thanks Wuzak, that makes sense.



#82 RogerGraham

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Posted 25 February 2014 - 14:18

This will be particularly true for turbo compound engines because heat energy removed by the intercooler is less energy available in the exhaust. (ie the optimum intake temperature might be even higher than 70*C)

 

GG, could you be kind enough to expand on this?  Combustion temperatures are quite high compared to intake air temps, but do you mean that to some extent at least, increasing the intake temps will nonetheless increase exhaust energy (temp?)?



#83 saudoso

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Posted 25 February 2014 - 16:13

As rusty as mi thermodynamics might be, wasn't there a compressing work penalty from the hotter intake air? (I mean piston stroke work)

 

I'm pretty sure someone rammed that into my head long ago. It went with the line that a jetliner's turbojet faced the most favourable conditions for maximum power when it least needed it (30k feet, -50c) and was requested the most power when it was harder to deliver (sea level, 45c air raising from the tarmac).

 

It might be only my poor memory and density was the only factor,or the jetliner example given to me is rubish, since I'd assume the altitude would kill the temp advantage.


Edited by saudoso, 25 February 2014 - 16:30.


#84 gruntguru

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Posted 25 February 2014 - 23:05

Roger Graham - Yes, any increase in intake temp will produce a similar increase in exhaust temp. A compound engine is like a gas turbine engine with a recip as the combustor. One common technique for increasing GT efficiency is to extract waste heat from the exhaust after the turbine and use it to heat the intake air between the compressor and the combustion chamber.

 

Saudoso - Any extra work expended due to higher pressure during the compression stroke will be recovered courtesy of higher pressure during the power stroke.

 

Jet engine "power" is proportional to airspeed. Zero airspeed = zero power.


Edited by gruntguru, 25 February 2014 - 23:08.


#85 saudoso

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Posted 26 February 2014 - 00:44

Roger Graham - Yes, any increase in intake temp will produce a similar increase in exhaust temp. A compound engine is like a gas turbine engine with a recip as the combustor. One common technique for increasing GT efficiency is to extract waste heat from the exhaust after the turbine and use it to heat the intake air between the compressor and the combustion chamber.

 

Saudoso - Any extra work expended due to higher pressure during the compression stroke will be recovered courtesy of higher pressure during the power stroke.

 

Jet engine "power" is proportional to airspeed. Zero airspeed = zero power.

Thrust I mean, but anyway... so air density is the only sensible factor.



#86 gruntguru

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Posted 26 February 2014 - 01:27

Of course the other consideration is that GTs including jet engines are predominantly limited by turbine inlet temperature (the highest temperature in the cycle) so the colder the intake air, the greater the possible power and efficiency.



#87 RogerGraham

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Posted 26 February 2014 - 02:25

Of course the other consideration is that GTs including jet engines are predominantly limited by turbine inlet temperature (the highest temperature in the cycle) so the colder the intake air, the greater the possible power and efficiency.

 

One common technique for increasing GT efficiency is to extract waste heat from the exhaust after the turbine and use it to heat the intake air between the compressor and the combustion chamber.

 

 

Of course the other consideration is that GTs including jet engines are predominantly limited by turbine inlet temperature (the highest temperature in the cycle) so the colder the intake air, the greater the possible power and efficiency.

 

Are these contradictory, or is it the distinction between "air between compressor and combustion chamber" and "intake air" that separates the statements?



#88 gruntguru

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Posted 26 February 2014 - 06:08

Starting with a simple GT (Brayton) cycle (no regenerator).

 

- Thermal efficiency is mainly a function of pressure ratio. Increasing pressure ratio (all else being equal) will increase turbine inlet temperature so efficiency is limited by metallurgical considerations.

 

- Power per unit airflow is limited by how much fuel (heat) is added and TE. Increasing either will increase turbine inlet temperature so power is also limited by turbine metallurgy.

 

Adding regen' simply reduces the amount of fuel required because some of the heating is now done with waste heat from the exhaust. Power per unit airflow will still have the same limit but TE will increase (less fuel burned for same power).



#89 RogerGraham

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Posted 26 February 2014 - 12:11

Ta... I think I have some reading to do!



#90 alexbiker

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Posted 26 February 2014 - 19:15

Shame about the wasteful reciprocating engine in the middle of the Power Unit, really. . . . 



#91 gruntguru

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Posted 26 February 2014 - 23:19

A GT would be more wasteful.



#92 Catalina Park

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Posted 27 February 2014 - 07:26

Shame about the wasteful reciprocating engine in the middle of the Power Unit, really. . . .

That makes me think of a pulse jet which is merely a two stroke engine without the engine.

#93 OnTheGas

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Posted 27 February 2014 - 07:51

Another point is that intercooling to near ambient is probably not necessary.

 

...2. Thermal efficiency improves with increasing air temp (peaking at 70*C and above from Honda experience with the RA168E) and thermal efficiency equals power under the 2014 rules.

 

I think its really really cool to see both water to air and air to air being tried. The benefits of each is clearly not sorted out in total.

 

water to air intercooler has the following:

...

 

Might have:

+ Variable water flow to tune cooling temp to optimum Termal efficeny ( i still struggle to understand how anything but cool air is optimum for maximum hp at peak power but thats my problem)...

 

...OTOH, if the available fuel can be burned more efficiently, the engine will be able to make more power. Read the Honda RA168E paper and you will see that intake air temps around 70*C and above produce the best thermal efficiency. This will be particularly true for turbo compound engines because heat energy removed by the intercooler is less energy available in the exhaust. (ie the optimum intake temperature might be even higher than 70*C)

...

To be clear, we would not know the optimum temperatures for the fuel and charged intake air of a 2014 engine from the RA168E.

 

In 1988, the only reason Honda pre-heated their fuel, and kept the charged intake air at 70*C for their RA168E was to help with fuel vaporization.

 

The factors controlling vaporization would include:

  • The chemical composition of the fuel
  • The fuel pressure at the injectors
  • The design of the injectors
  • The thermal environment inside the cylinder during intake and compression strokes
  • The bore size, stroke length, and cylinder head design

So while it's not safe to assume that today's 2014 F1 engines require 70*C intake air, gruntguru is certainly right to show us the example of Honda finding that it's possible to lose efficiency by over-cooling the charged intake air of a turbo-charged engine. Thanks for that!



#94 alexbiker

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Posted 05 March 2014 - 22:21

http://www.grandprix...ns/ns27449.html

 

Lauda says 580bhp for the V6 - now, add 160bhp for ERS-K, and what I'd really like to know is - how much at full throttle is going from MGU-H into the MGU-K directly, which is unlimited?  Any educated guesses?  740bhp +. . . . . ?


Edited by alexbiker, 05 March 2014 - 22:22.


#95 Wuzak

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Posted 05 March 2014 - 23:46

http://www.grandprix...ns/ns27449.html

 

Lauda says 580bhp for the V6 - now, add 160bhp for ERS-K, and what I'd really like to know is - how much at full throttle is going from MGU-H into the MGU-K directly, which is unlimited?  Any educated guesses?  740bhp +. . . . . ?

 

0hp!

 

Any power the MGU-H develops has to be transmitted via the MGU-K (whether it is directly or via the ES). The MGU-H is restricted to 160hp.

 

That means if the MGU-H can recover 100hp around peak power rpm, which Cosworth's estimates show, then only 60hp need be extracted from teh ES to give maximum power.



#96 Youichi

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Posted 06 March 2014 - 15:16

0hp!

 

Any power the MGU-H develops has to be transmitted via the MGU-K (whether it is directly or via the ES). The MGU-H is restricted to 160hp.

 

That means if the MGU-H can recover 100hp around peak power rpm, which Cosworth's estimates show, then only 60hp need be extracted from teh ES to give maximum power.

 

Wuzak, check the regs again, the only limits are to-from the Energy Store, the MGU-H to MGU-K is unlimited, the diagram in Appendix 3 explicitly states this.

 

So 580 +  160 + 100 = 840hp.

 

Which presupposes that one would still be using the ES-to-MGU-K energy when one reaches the point where one is recovering from the MGU-H, which may or may not be optimal from a lap-time perspective.


Edited by Youichi, 06 March 2014 - 15:25.


#97 TC3000

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Posted 06 March 2014 - 16:57

The diagram you mention shows the ENERGY flow, and the ENERGY flow from the MGU-h to the MGU-k is not limited, only the ENERGY flow from the ES to the MGU-k is.

Nevertheless, there is a maximum POWER limit for the MGU-k to the engine, which applies under all conditions (see extract from the diagram below), independent of where the ENERGY comes from.

 

It's two completely different things.

 

Therefore, if you have xxx kW from your ICE you can have only a maximum of xxx kW + 120 kW (app. 160 hp) [coming from the MGU-k] in total.

 

 

Energy flows, power and ES state of charge limits are defined in the energy flow diagram

shown in Appendix 3 of these regulations.
 
**************************************************************************************************************
The MGU-K must be solely and permanently mechanically linked to the powertrain before the
main clutch. This mechanical link must be of fixed speed ratio to the engine crankshaft.
The rotational speed of the MGU-K may not exceed 50,000rpm.
The maximum torque of the MGU-K may not exceed 200Nm. The torque will be referenced to
the crankshaft speed and the fixed efficiency correction defined in Article 5.2.2 will be used to
monitor the maximum MGU-K torque.
 
Gjwen2K.jpg

Edited by TC3000, 06 March 2014 - 17:02.


#98 Lee Nicolle

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Posted 06 March 2014 - 23:01

Is it just me asking WHY? The first thing about motorsport is the KISS principle. Which these cars are so stupidly high tech so reliability is out the door. This is not motorsport anymore. Just waste cubic dollars on totally unesecary stuff. 

The rules for F1 should be simple, capacity, no of cylinders and maybe a reasonable fuel limit. Not electric motors and batteries with all their dramas and safety issues. What for a team should be simple, the fastest car around a track, and the best driver to get it around the track the fastest has been lost.. If as some predict the majority,, all the cars dont make the finish of a race it is hardly a spectacle.

And while we are at it severely restrict the aero so the cars look like cars and the drivers have to drive them. It will be a bit slower, but a far better spectacle and probably 50% cheaper too.



#99 Wuzak

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Posted 06 March 2014 - 23:32

If cars were to look like cars then they wouldn't be open wheel. They wouldn't be Grand Prix cars (I know there were one or two in the past that had closed wheels, but the vast majority of Grand Prix cars have been open wheel).

 

There are plenty of series that follow the ideas that you put forth. Let's not make F1 just another series.

 

Also, the hybrid rules are attractive to the manufacturers. Since it is where they are headed in production vehicles.



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#100 gruntguru

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Posted 06 March 2014 - 23:46

WHY? Technological relevance. The governing body is taking a stab at where automotive technology is headed and getting a jump. 2014 F1 cars will have the same power but use 35% less fuel. That's 100kg instead of 160kg.

 

OTOH they could make F1 another spec class. We don't have enough of those around the world already.

 

EDIT. OOPS looks like I am on the same page as you Wuzak.


Edited by gruntguru, 06 March 2014 - 23:48.