Will we still hear the external wastegates venting in 2022?

[saviour stivala]

‘’F1 exhaust goes to the turbine via 2 separate collectors’’ As long as the waste-gate/s are closed it does. Once the waste-gate/s are open it does not.

[henry]

‘’F1 exhaust goes to the turbine via 2 separate collectors’’ As long as the waste-gate/s are closed it does. Once the waste-gate/s are open it does not.

Where do you think the wastegate(s) are positioned to behave as you say?

My observation is that there is usually only one and positioned some way from the junctions that connect it to the exhaust collectors.

[saviour stivala]

‘’Where do you think waste-gate/s are positioned to behave as you think’’ It is not where waste-gate/s are positioned. It is where exhaust diverter pipe to waste-gate/s are positioned/connected on the collector pipe before collector pipe connects to turbine housing.

[yelistener]

Mercedes Andy Cowell kinda explained how wastegate is positioned in one of their videos, at 00:45.

[saviour stivala]

Mercedes Andy Cowell kinda explained how wastegate is positioned in one of their videos, at 00:45.

https://www.youtube.com/watch?v=R0-jINmEYNQ

Thanks for the link which clearly confirms what I have been saying namely that, the cylinders exhaust gases are convened to the pressure turbine wheel through a collector pipe, with two possible paths. Either through a waste-gate or through the turbine wheel.

[henry]

Mercedes Andy Cowell kinda explained how wastegate is positioned in one of their videos, at 00:45.

https://www.youtube.com/watch?v=R0-jINmEYNQ

Thanks for the link which clearly confirms what I have been saying namely that, the cylinders exhaust gases are convened to the pressure turbine wheel through a collector pipe, with two possible paths. Either through a waste-gate or through the turbine wheel.

Yes there are two possible paths. The question is, why does the exhaust stream choose one path over the other rather than using both? As I believe @Tommy Cookers pointed out the pressure at the end of both paths is atmospheric. So rather than an alternative path the open wastegate adds a supplementary path.

Typically the pipe from the collector to the wastegate joins at 90° encouraging high energy (blowdown) gases to continue to the turbine whilst the two available paths to atmospheric reduce the pressure in the manifolds.

No doubt you disagree.

[gruntguru]

With a radial inflow turbine spinning at high speed (courtesy of the MGUH) there will be significant pressure required for exhaust gas to flow through it. The majority of the exhaust will therefore pass through the wastegate with only high pressure pulses able to fight their way through. Axial flow turbines do not have this backpressure issue. Mixed (radial-axial) flow turbines sit somewhere in between.

[henry]

With a radial inflow turbine spinning at high speed (courtesy of the MGUH) there will be significant pressure required for exhaust gas to flow through it. The majority of the exhaust will therefore pass through the wastegate with only high pressure pulses able to fight their way through. Axial flow turbines do not have this backpressure issue. Mixed (radial-axial) flow turbines sit somewhere in between.

Thanks. I stand corrected.

[saviour stivala]

Unlike the ‘blow-down – pulse-type’ of exhaust gas turbine, which greats no adverse back pressure effect while harvesting exhaust gas pulse energy on engine cylinders, and so does not need the use of a waste-gate incorporated into the design set-up. The radial pressure type of turbine, a design that does necessitates the need to incorporate a ‘waste-gate’ into the design set-up. The pressure type of radial turbine design waste-gate can be used in one of two ways, a build-in (into the turbine housing) a design that can ‘only relives’ the exhaust gas pressure build-up inside the turbine housing. Or An external waste-gate, build into the exhaust piping supplying the turbine, this design set-up, when fully open will bypass exhaust gases away from the turbine, completely eliminating any exhaust gas pressure inside both the turbine and the collector pipe supplying turbine. With this waste-gate set-up, no turbine harvesting is possible when waste-gate is fully open. Because exhaust gases will chose to travel the path of least resistance. This answers the question of (why does the exhaust stream chose one path over the other?). So yes. Unfortunately I cannot agree.

[Tommy Cookers]

regardless of who is at this point is disagreeing with what .....

isn't the wastegate pipe still limited to a diameter far smaller than the exhaust pipe diameter ?
if so wouldn't this have implications re. whether the WG is a pressure-relief channel or a 100% flow-diversion channel ?

so in what is rather inaccurately called electric supercharge either .....
the turbine is rotated electrically by MU-H action at maybe 120000 rpm in near-vacuum ?
or partly rotated by gas at maybe 120000 rpm in near ambient pressure ?

does ES even use full boost ?
ES at partial boost (via reduced leaning) would extend ES duration without loss of ES power
as MU-H power is much less (and ICE friction is less) with lower boost
this of course briefly (for cooling reasons) - but all ES running is brief anyway

[saviour stivala]

On the formula one turbo set-up when waste-gate is fully open collector pipe is at atmospheric pressure regardless of the doubts about the size of waste-gate exhaust pipe. so no recovery by the turbine is possible. With the waste-gate fully open and MGU-H spinning the turbo shaft with the turbine wheel going along for a free spin (electric supercharging mode – free load mode) it was already estimated before the power units were even ran on track that the ICE power could be boosted by 20kw/27bhp.

[gruntguru]

Unlike the ‘blow-down – pulse-type’ of exhaust gas turbine, which greats no adverse back pressure effect while harvesting exhaust gas pulse energy on engine cylinders, and so does not need the use of a waste-gate incorporated into the design set-up.

???? The purpose of a wastegate is to control/limit boost pressure or turbine overspeed. There may be instances where a blowdown turbine requires a wastegate to control one or both of these.

The radial pressure type of turbine, a design that does necessitates the need to incorporate a ‘waste-gate’ into the design set-up.

It is quite common for a radial turbocharger system to be designed with no wastegate.

The pressure type of radial turbine design waste-gate can be used in one of two ways, a build-in (into the turbine housing) a design that can ‘only relives’ the exhaust gas pressure build-up inside the turbine housing. Or An external waste-gate, build into the exhaust piping supplying the turbine, this design set-up, when fully open will bypass exhaust gases away from the turbine, completely eliminating any exhaust gas pressure inside both the turbine and the collector pipe supplying turbine. With this waste-gate set-up, no turbine harvesting is possible when waste-gate is fully open. Because exhaust gases will chose to travel the path of least resistance.

It is very rare to see a turbocharger system where exhaust pressure is reduced to zero. In almost all cases, the turbine continues to drive the compressor even while the wastegate is opened sufficiently to control the boost.

Formula 1 is an exception. Firstly the wastegate does not control boost. Boost is controlled by the MGUH in G mode. Secondly the MGUH in M mode can provide enough power to run the supercharger with zero exhaust backpressure.

This answers the question of (why does the exhaust stream chose one path over the other?). So yes. Unfortunately I cannot agree.

It may be the case that F1 does not utilise any blowdown pulse energy during electric supercharger mode, but it is by no means certain. With appropriate turbine and wastegate design it is certainly possible and even 10 or 20 hp of capture would reduce the ES drawdown during electric supercharger mode and permit additional deployment.

[gruntguru]

On the formula one turbo set-up when waste-gate is fully open collector pipe is at atmospheric pressure regardless of the doubts about the size of waste-gate exhaust pipe. so no recovery by the turbine is possible.

If the wastegate plumbing or the orifice of the wastegate itself are not of sufficient cross sectional area, there will be a pressure drop and the exhaust manifold will not be able to reduce fully to atmospheric pressure.

[saviour stivala]

The turbocharging system used in F1 is different from that used by the majority of normal road cars. In F1 when the waste-gate is fully opened it is meant to reduce exhaust pressure in collector to zero. Because only with exhaust collector pressure at zero can the electric supercharging mode extract maximum possible power from the ICE. With the exhaust collector pressure at zero, the turbine wheel being fixed to compressor shaft, it is just getting a ride on shaft. As is the function of the waste-gate of a F1 turbo, it does not control boost, it makes sure that when fully open exhaust gas pressure in collector is zero. The exhaust stream of a F1 exhaust piping system from engine to turbo will chose the path of least resistance when waste-gate is fully open. End the least resistance path is through the waste-gate and not through the turbine. In electric supercharging mode with waste-gat fully open. The F1 turbo cannot utilise blowdown pulses energy because of a fully open waste-gate. And with waste-gate closed and turbine being powered by exhaust gas pressure. I doubt how much use it can make of blowdown pulse energy. This because as far as I know all four PU’S on the grid uses an exhaust pressure collector for a path for exhaust gases to turbine and not the proper exhaust piping conductive to make best use of blowdown pulse energy. ( 07 oct 2014 ‘’blowdown energy is free’’ by GR – To harness this energy the pressure pulse must be piped to the turbo without adding pressure to the exhaust of any cylinder)

[Pat Pending]

The turbocharging system used in F1 is different from that used by the majority of normal road cars. In F1 when the waste-gate is fully opened it is meant to reduce exhaust pressure in collector to zero. Because only with exhaust collector pressure at zero can the electric supercharging mode extract maximum possible power from the ICE. With the exhaust collector pressure at zero, the turbine wheel being fixed to compressor shaft, it is just getting a ride on shaft. As is the function of the waste-gate of a F1 turbo, it does not control boost, it makes sure that when fully open exhaust gas pressure in collector is zero. The exhaust stream of a F1 exhaust piping system from engine to turbo will chose the path of least resistance when waste-gate is fully open. End the least resistance path is through the waste-gate and not through the turbine. In electric supercharging mode with waste-gat fully open. The F1 turbo cannot utilise blowdown pulses energy because of a fully open waste-gate. And with waste-gate closed and turbine being powered by exhaust gas pressure. I doubt how much use it can make of blowdown pulse energy. This because as far as I know all four PU’S on the grid uses an exhaust pressure collector for a path for exhaust gases to turbine and not the proper exhaust piping conductive to make best use of blowdown pulse energy. ( 07 oct 2014 ‘’blowdown energy is free’’ by GR – To harness this energy the pressure pulse must be piped to the turbo without adding pressure to the exhaust of any cylinder)

If I've followed that correctly (and I may not have done!), you're describing a mode of operation in which you are electrically driving the compressor in preference to using available exhaust gas energy/flow. Why would you do that?

And if that's correct then presumably the waste-gate operation is not dependent on the intake pressure (as I understand it to be in road car applications)?