Exhaust blown technology for turbos ?

[Rolly7]

I was just wondering whether exhaust blown technology as applied by renault on aerodynamics would have any benefits being applied to the turbine and mgu-h as far as turbo lag and energy recovery is concerned

Cheers

[wuzak]

The exhaust locations have specifically been chosen to negate that effect.

Plus with the MGUH doing most of the speed control duties and a large turbine, there isn't as much energy as the V8 exhausts.

[PlatinumZealot]

I was just wondering whether exhaust blown technology as applied by renault on aerodynamics would have any benefits being applied to the turbine and mgu-h as far as turbo lag and energy recovery is concerned

Cheers

You hear how quiet the turbos are? This is a hint to what happens to the exhaust gasses after they pass through the turbos. The gas give up nearly 70% their internal energy in the from of heat. So exhaust blowing would not be as effective using a turbo. You could try to force more gas by using the waste-gate or dumping more energy into the turbo but you risk blowing up the thing.

Don't get me wrong It can be done but it will be an interesting balance between lap time/Fuel efficiency/Engine reliability/Blowing your turbo to smithereens

[pgfpro]

I was just wondering whether exhaust blown technology as applied by renault on aerodynamics would have any benefits being applied to the turbine and mgu-h as far as turbo lag and energy recovery is concerned

Cheers

You hear how quiet the turbos are? This is a hint to what happens to the exhaust gasses after they pass through the turbos. The gas give up nearly 70% their internal energy in the from of heat. So exhaust blowing would not be as effective using a turbo. You could try to force more gas by using the waste-gate or dumping more energy into the turbo but you risk blowing up the thing.

Don't get me wrong It can be done but it will be an interesting balance between lap time/Fuel efficiency/Engine reliability/Blowing your turbo to smithereens

You would be surprised to know how much energy is left over after the turbo. On my Talon I'm running a "staged turbo compound system". The low pressure turbo is a mid mount about 9 feet away from the high pressure turbo. I had several people tell me that this won't work based on a loss of energy due to the distance between the turbos. Well they were all wrong. The mid-mount low pressure turbo in which is the larger of the two spools instantly!!! The heat at the turbine after a pull is so bad I had to build a insulated containment box.

[Tommy Cookers]

......You hear how quiet the turbos are? This is a hint to what happens to the exhaust gasses after they pass through the turbos. The gas give up nearly 70% their internal energy in the from of heat. So exhaust blowing would not be as effective using a turbo. .....

'gives up nearly 70% of their internal energy in the form of heat' ......
sincere question ....
how much internal energy can ever be given up and how much will remain as sensible heat ungiveable up to even a perfect turbine ??
of course in an SI engine a recovery turbine will do much more recovery than a turbine that just drives a compressor

[NL_Fer]

Doesn't he mean hot blowing the turbocharger? Running the ignition late, to increase hot exhaust gasses, during half throttle periods?

I can imagen this during qually rounds, recover energy during medium throttle parts of the tracks, running with opended wastegate on the straights.

[Brian Coat]

Doesn't he mean hot blowing the turbocharger? Running the ignition late, to increase hot exhaust gasses, during half throttle periods?

Yes, PtZ and others have proposed this control strategy in "the big thread".

My view: Daft not to try/do this and not just in qualifying.

[gruntguru]

You would only do that if you are on the per-lap harvest limit for the MGUK and you want to charge the ES further from the MGUH. The electrical energy you get doing this would come at a far greater fuel cost than the same energy from the MGUK.

[Brian Coat]

That is correct of course.

Do we not think it is likely that teams will be interested to use (some) fuel inefficiently to extend peak power deployment duration?

[NL_Fer]

I think, if you where running a lap under "self sustaining mode" (running with the wastegate open, driving the turbo with mgu-h) the ES will be depleted very fast, because the mgu-h is using energy, instead of harvasting, while using this mode.

During such a lap ( for example in qualifing) i can imagin, you would use hot blowing, to harvest during half throttle instead.

[Pierce89]

I think, if you where running a lap under "self sustaining mode" (running with the wastegate open, driving the turbo with mgu-h) the ES will be depleted very fast, because the mgu-h is using energy, instead of harvasting, while using this mode.

During such a lap ( for example in qualifing) i can imagin, you would use hot blowing, to harvest during half throttle instead.

Self-sustaining mode is not what you wrote. Self-sustaining mode is where the mguh power goes straight to the mguk. There is no charging or discharging of the ES.

[trinidefender]

I think, if you where running a lap under "self sustaining mode" (running with the wastegate open, driving the turbo with mgu-h) the ES will be depleted very fast, because the mgu-h is using energy, instead of harvasting, while using this mode.

During such a lap ( for example in qualifing) i can imagin, you would use hot blowing, to harvest during half throttle instead.

What the.....

Wowwwwww

Self sustaining mode is the exact opposite of what you described. How can that ever sustain itself. As was said by Pierce, self sustaining is where any power generated by the MGU-H is sent directly to the MGU-K. Therefore it can be defined as the PU is only generating the amount of power that can be made without using any electrical energy from the ES.

Running with the wastegate open can never sustain itself (as the name suggests) as it has to keep drawing electrical power from the ES to power the MGU-H.

[FW17]

I always felt Merc were hot blowing the turbine

[NL_Fer]

Sorry i can't remember all the f1 technical glossary.

Still it is mentioned several times, that during a hot lap. Teams run keep the waste gate open for some periods, to remove the backpressure for the engine and drive the turbo with the mgu-h. If you do this for even a few seconds, at the beginning af a straight, you can gain allot of time.

So hot blowing the turbo, to harvest during medium throttle periods, can compensate, for the electrical power consumed by the mgu-h. Fuel consumption is not an issue, during qualifing.