2014-2020 Formula One 1.6l V6 turbo engine formula

[pgfpro]

Ok, I got that, but nothing says two separate entries at different phases in the turbine cycle, right? Because I was being led to believe that it was the only way to do it a few pages back.

Correct!!!

About Twin Scroll:Twin scroll turbo system design addresses many of the shortcomings of single scroll turbo systems by separating those cylinders whose exhaust gas pulses interfere with each other. Similar in concept to pairing cylinders on race headers for N/A engines, twin scroll design pairs cylinders to one side of the turbine inlet so that the kinetic energy from the exhaust gases is recovered more efficiently by the turbine. For example, if a four-cylinder engine’s firing sequence is 1-3-4-2, cylinder 1 is ending its expansion stroke and opening its exhaust valves while cylinder 2 still has its exhaust valves open (while in its overlap period, where both the intake and exhaust valves are partially open at the same time). In a single scroll AKA undivided manifold, the exhaust gas pressure pulse from cylinder 1 is therefore going to interfere with cylinder 2’s ability to expel its exhaust gases, rather than delivering it undisturbed to the turbo’s turbine the way a twin scroll system allows.

The result of the superior scavenging effect from a twin scroll design is better pressure distribution in the exhaust ports and more efficient delivery of exhaust gas energy to the turbocharger’s turbine. This in turn allows greater valve overlap, resulting in an improved quality and quantity of the air charge entering each cylinder. In fact, with more valve overlap, the scavenging effect of the exhaust flow can literally draw more air in on the intake side while drawing out the last of the low-pressure exhaust gases, helping pack each cylinder with a denser and purer air charge. As we all know, a denser and purer air charge means stronger combustion and more power... but the benefits of twin scroll design don’t end there. With its greater volumetric efficiency and stronger scavenging effect, higher ignition delay can be used, which helps keep peak combustion temperature in the cylinders down. Since cooler cylinder temperatures and lower exhaust gas temperatures allows for a leaner air/fuel ratio, twin scroll turbo design has been shown to increase turbine efficiency by 7-8 percent (faster spool, quicker response) and result in fuel efficiency improvements as high as 5 percent. It is wise to size the turbine housing A/R larger than the single scroll turbine A/R typically used!

Here's a Full Race manifold single entry twin scroll.


Single entry twin scroll's is where the word "twin scroll" came from. The mono-turbo dual entry twin scroll is a new hybrid design.

[wuzak]

Ok, I got that, but nothing says two separate entries at different phases in the turbine cycle, right? Because I was being led to believe that it was the only way to do it a few pages back.

Right. I understand that you mean by "different phases" a system like the Audi "mono turbo"?

There is no reason why a single, split entry couldn't work. In fact that appears to be what Mercedes-Benz have. However, plumbing the exhaust to that may be quite tricky. In the M-B pictures it appears that the inlet is pointing down. That means that the exhausts would have to come from the sides and bend up to meet the flange. Because that is just above where the gearbox mounts the bends may have to be quite sharp.

Two entries, as on the "mono turbo" allow for a neater exhaust solution.

As shown in this rendering

[rjsa]

Thank both for the lessons.

[wuzak]

And in this one it appear sas if the exhauts would be going to a dual entry turbo.

http://www.ausmotive.com/F1/2013/Renaul ... ine-01.jpg

[autogyro]

If it was an eight cylinder engine I would expect a dual entry twin scroll turbo with dual entries one on each side.
However with three cylinders on each side that is not possible.
The exhaust manifolds shown in the pictures surprise me though, three equal length pipes into a single collector.
I would have expected a beter scavenge arrangement than that pre turbo,
The inlet to the compressor pointing down to the hot exhaust and other weird pipeing make me wonder.

[dren]

I would expect packaging considerations for single and dual entry on the turbine would be heavily weighed. There certainly would be some sharp bends for a single entry, especially since the turbo location doesn't allow for much manipulation.

Is there any benefit to the turbo efficiency if you have dual entry 180 degrees apart compared to the single entry dual scroll?

[pgfpro]

I would expect packaging considerations for single and dual entry on the turbine would be heavily weighed. There certainly would be some sharp bends for a single entry, especially since the turbo location doesn't allow for much manipulation.

Is there any benefit to the turbo efficiency if you have dual entry 180 degrees apart compared to the single entry dual scroll?

That's the major question!!!

IMO I don't think the double entry monoturbo style will be as good as the single entry.

The monoturbo diesel engine that's is used is running a very narrow rpm range(aftering watching video it looks like 3200rpm to 4200rpm). What happens when it has to be ran at a wider rpm range (8000rpm to 12000rpm)?

What about the rpm itself. The monoturbo diesel engine today is at 4500rpm max about what the new F1 engines will idle at. What will it do at 12000rpm plus? Engine rpm pluse plays a major role in turbine efficiency. Engine pulse change from rpm is the most engineer part of the turbine and its design.

What would the mono turbo do without VGT??? Audi and Garrett both have said the monoturbo needs VGT to work properly.

What will the monoturbo due on petrol???

Now the single entry turbo has all ready proven itself in the record books. Until the monoturbo dual entry can prove itself on a petrol, high rpm engine, I will have to go with the single entry turbo design.

[wuzak]

Sure, and the Mono Turbo was designed for a 3.7l Diesel.

If one was designed around a 1.6l petrol engine then its design parameters would be different.

[pgfpro]

Anybody got any exhaust gas flow diagrams for a turbocharger.
I cant see why the flow has to go 360 degrees to extract all the energy.
The shape of the blades will deflect the gas to outlet long before that IMO.

I came up with this one in mach numbers. I'm trying to find some detailed ones on my other work computer.



This is your average OEM size turbo for a 2.0L 9 blade turbine wheel @ 3000rpm full load and frequency, mass flow and temperature corresponding, no waste gate producing around 40hp gross at the shaft.

[wuzak]

Isn't your turbo lacking some details?

[rjsa]

Having two ntakes entering phased 180 degrees does not mean each one of the scrolls will be 180 degrees long only, they might very well be 360 degrees long each.

What I've been thinking here is that may be there will be a raise in average turbine blade temperature.

[ozzimark]

Anybody got any exhaust gas flow diagrams for a turbocharger.
I cant see why the flow has to go 360 degrees to extract all the energy.
The shape of the blades will deflect the gas to outlet long before that IMO.

A pulse acting on 180º of the turbine wheel will result in a net radial force that the bearings have to cope with, which is not ideal in many aspects.

[autogyro]

A pulse acting on 180º of the turbine wheel will result in a net radial force that the bearings have to cope with, which is not ideal in many aspects.

Dual exhaust inlets 180 degrees apart on each seperate scroll should balance the forces on the bearings.
I was interested in whether the full possible energy from the exhaust can be extracted from 180 degrees.
Of course with dual scrolls and inlets 180 degrees apart both scrolls can have 360 degrees of exhaust application.

[pgfpro]

Another pic of turbine flow at the wheel.

[WhiteBlue]

I'm sorry for missing much of the discussion but I was down with the flu. So we all seem to agree that a turbine with two entries - one for each bank of cylinders - is the likely design for the 2014 engines? I reckon that the engineers would probably have loved to do the old bi turbo design from the 80ties. But they have to use a single turbine according to the rules.

So what would be a logical assumption for a 90°V6? I would think the firing order would be at 120° even 1-2-3-4-5-6 with 1,3,5 on the left bank and 2,4,6 on the right bank. The three equal length pipes would end in a collector that each runs into one turbine entry. The turbine entries are 180° apart. That way the collector sees the widest possible time intervall of 240° crank angle between two exhaust pressure peaks. The turbine naturally gets a pulse every 120° and the final exhaust pipe would also get this high frequency. I'm quite confident that such a design would optimize combustion efficiency and over all power generation. It is also the best packaging solution.