TERS : Thermal Energy Recovery System

[pgfpro]

I believe it will not work as shown in the diagram because the turbo has no waste gate. In fact it has a negative waste gate. It gets spooled up by battery power which you cannot show in a conventional turbo diagram. As rpm and mass flow builds the spool up power from the MGU is reduced to zero. Somewhere between 0-20 hp compressor power and 62 hp turbine power you cross that point. Then the MGU goes continuously into generation mode as turbine power keeps building up to the full 124 hp and compressor power keeps building up to 40hp. It is a continuous steady function of increasing the power of both units. The electricity generation has the function of the waste gate in a conventional turbo. It absorbs the excess power when the turbine has reached the cross over point.

So are you saying when the MGUH goes into generation mode and puts a load on the turbine there won't be an increase in turbine pressure???
In my example the blue dot is after the full spool from the battery power. At this point you have almost reach max flow through the turbine. IMO you have to be at max turbine flow with a radial turbo before you can start adding a generator load to the turbine.

I have not talked about the turbine pressure at all. So that is indeed not what I'm saying. Turbine and compressor pressures are dynamic values building continually up as the turbo spools up. There will be no interruption of the pressure build up when the MGU-H controller reaches the cross over point. The pressures will simply keep building up while generator load is build on the turbine.
I don't know if your turbo diagram was made for an electric assist turbo charger. I suspect it is for an existing radial turbine. If I remember it correctly Ringo and I assumed in our input data a very high turbine efficiency as you see typically for an axial turbine. The idea was taken again from the Whright air craft turbo compounded engine which features three axial turbines for 18 pistons. In the F1 engine you will also have one turbine for six pistons. So the ratio is identical. We figured that an increase in manufacturing cost of an axial turbine compared to a radial would not stop the designers to use the most efficient design. The 2014 engine design will be totally focussed on milking the last available hp from those 27.8g of fuel flow that is allowed. Gaining a few points in turbine efficiency will be one path to achieving that.
As I have said before I'm not experienced in this field and I do not use such diagrams routinely. Perhaps it would help me if you explain how you got to the diagram and why it is applicable to the kind of design that F1 engine designers are likely to use in 2014. I could learn something useful that way.

IMO I think that the new 2014 F1 turbocharge engines will be using a radial turbo charger for these reasons.
1) The F1 drawings that we have seen so far look like a radial turbo.
2) Garrett Honeywell has had a radial turbocharger with an electric generator cartridge for a long time now. That helps spool and generates electric power.
3) Up to a wheel diameter of about 160 mm, today's radial-flow turbines are used. This corresponds to an engine power of approximately 1000 kW per turbocharger. From 300 mm onwards, only axial-flow turbines are used.
4) Turbine Wheel to turbine housing clearances are way more forgiving in a radial form and already proven in harsh road racing condition's WRC comes to mind.
5) F1 Technical Regulations mention of waste gate exit ( 5.3.8 )"Exhaust pipes beyond the turbine exit and beyond any waste gate exit".

The example diagram is from Borg Warner's "Match Bot" turbo turbine selector. Its a over simplified turbine phi curve plot to show that a load from the MGUH would increase back pressure. I have several more turbine maps I will show later.
The vertical part of the curve is where turbine mass flow increases. It then reaches a point that you can see where it levels off and moves to the right of the map. Mass flow is vertical and turbine pressure is left to right. Mass flow levels off and turbine pressure increase. This is the point where the turbine becomes more efficient. Keep in mind that I used this turbine plot based on the size of the picture and for visualization. Radial turbine maps have several different curves. Some are more like a bell curve while other are vertical and some are almost flat.

[pgfpro]

Turbine maps.







One thing to keep in mind while looking at these maps is large A/R are more efficient at a lower pressure ratio and smaller A/R are more efficient at higher pressure ratios.

[Vegetabill]

Don't know if this is of any use for this thread but I recently worked on a feasabilty study for using TEGs to harvest waste heat energy from gas turbine exhausts on ships. As technology stands at present the tiles are quite large and need a delta T of around 300 degrees C between hot and cold sides to produce maximum electricity (any more than this will damage the tile). Even then the output is quite low (nowhere near as efficient as KERs) and I cannot imagine the weight of the tiles you would need to produce a significant amount would be considered an option in an F1car. However, what maybe of more interest is that the TEGs also work in reverse. Meaning you input a small amount of electricity and get the 300 C temperature differential. I am no expert in car design but their fouls be areas this can be of use, maybe for heating tires or on the car floor to manipulate airflow?

[dan5150]

Hello all, this is my first ever post.

I have been reading with much interest this thread as it is (very) relevant to my current work.

I would like to slightly expand on wastegating. I was always by first reaction in agreement with many of you that the rules effectively self regulate to a point where wastegating is not necessary because after 10,500 rpm there can be no more fuel input to the system.

However in the main 1.6L thread it has been discussed that feed to two cylinders may be cut above that critical speed. This scenario would lead to wastegating being necessary (I guess).

I dont know where you all work but is any one able to say one way or the other what is the current situation with this? My personal belief is that cutting the number of active cylinders, despite being very convenient, even if technically legal now, would probably be banned soon after utilisation.

And/or are there any other potential reasons why a wastegate may still be necessary?

Many thanks wise ones

[Tommy Cookers]

[quote="dan5150"}

I have been reading with much interest this thread as it is (very) relevant to my current work.

I was always by first reaction in agreement with many of you that the rules effectively self regulate to a point where wastegating is not necessary because after 10,500 rpm there can be no more fuel input to the system.
However in the main 1.6L thread it has been discussed that feed to two cylinders may be cut above that critical speed. This scenario would lead to wastegating being necessary (I guess).
.... cutting the number of active cylinders, despite being very convenient, even if technically legal now, would probably be banned soon after utilisation.
And/or are there any other potential reasons why a wastegate may still be necessary?[/quote]

relative to most other turbo applications the 2014 has less need for wastegating because the turbo speed is continuously controlled by the MGUT functionality
(motoring up to speed and generating when speed tends to excess, the turbine being larger than needed for supercharging)

FWIW (as one who suggested modulating from 6 to 5 cylinders) AFAIK such modulated displacement is not permitted

may I ask a little about your current work ??

[dan5150]

relative to most other turbo applications the 2014 has less need for wastegating because the turbo speed is continuously controlled by the MGUT functionality
(motoring up to speed and generating when speed tends to excess, the turbine being larger than needed for supercharging)

FWIW (as one who suggested modulating from 6 to 5 cylinders) AFAIK such modulated displacement is not permitted

Thanks for the reply, I must of missed the clause where it outlaws that kind of thing! sorry! (Which one is it?)
I am interested in modelling the power system for my employer (interested in or 'asked to', there is a crossover somewhere there).
At the risk therefore of being thrown on to another thread, has any one already weighed up the 1.4L or 1.5L option for the higher speeds as opposed to a choked 1.6?

[WhiteBlue]

I do not see much sense in the cutting of cylinders for the 2014 engine configuration. Cylinder cutting is mainly used as a way of saving fuel when the engine runs under less than top power requirements. For the 2014 engines it makes no sense IMHO. The engine has plenty of options to deal with mid range power requirements which would probably make more sense. By cutting cylinders you would be keeping the revs up which is increasing the frictional losses of the engine. If the engines runs with higher boost and lower revs you save plenty of friction losses and that is the preferred way they will probably save fuel or maximize the power in the mid range. Low revs also help getting the engine into operating conditions where you can lean out the air fuel ratio by stratifying. You have to consider that you are committed to the bulk of the friction losses of the two cylinders. By cutting the fuel flow you cannot all the sudden achieve zero friction in the additional moving parts.

So the concept in itself appears not very useful. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

[dan5150]

I do not see much sense in the cutting of cylinders for the 2014 engine configuration. Cylinder cutting is mainly used as a way of saving fuel when the engine runs under less than top power requirements. For the 2014 engines it makes no sense IMHO. The engine has plenty of options to deal with mid range power requirements which would probably make more sense. By cutting cylinders you would be keeping the revs up which is increasing the frictional losses of the engine. If the engines runs with higher boost and lower revs you save plenty of friction losses and that is the preferred way they will probably save fuel or maximize the power in the mid range. Low revs also help getting the engine into operating conditions where you can lean out the air fuel ratio by stratifying. You have to consider that you are committed to the bulk of the friction losses of the two cylinders. By cutting the fuel flow you cannot all the sudden achieve zero friction in the additional moving parts.

So the concept in itself appears not very useful. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

Ok, so it does not have viability due to the frictional and pumping losses, yes this makes sense........ confirmed by Renault did you say? I have not seen that press release or read this anywhere yet.

[WhiteBlue]

Read the Renault story in racecar engineering.

[dan5150]

Thanks, ok I will let you know how my gt power simulation goes if you're interested, still working on it.

[olefud]

. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

Any thought as to what would be done with excess energy if electrical storage is maxed out and the turbo needed modulation to limit boost?

[wuzak]

. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

Any thought as to what would be done with excess energy if electrical storage is maxed out and the turbo needed modulation to limit boost?

It would be directed into the MGUK.

[WhiteBlue]

. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

Any thought as to what would be done with excess energy if electrical storage is maxed out and the turbo needed modulation to limit boost?

It would be directed into the MGUK.

Indeed, the MGUH output would generally be as much as possible directed to the MGUK for more power. This would be preferred over storing the energy because it would see lower converting losses.

[autogyro]

If you made the MGUH the same unit as the MGUK and made it also integrated within the gearbox.
You could then use the nose of the crankshaft to drive the compressor in the engine V via a one way clutch (sprag).
The turbine could then step down drive into the gearbox using electro magnetic drive without the need for batteries.
The mechanical drive to the compressor (supercharger) would maintain boost at all but full boost requirements.
When full turbo boost was needed the turbine would clutch in and over speed the mechanical supercharger drive negating its torque loss to give full turbo boost from the compressor, controlled by balancing the exhaust turbine torque applied to the gearbox against the turbines rpm boost limit through fueling.
That is two less major components and no batteries other than for brake harvesting.
Hmmm, one day.

[olefud]

. Regarding its impact on the need of a waste gate I don't see implications. The load control of the turbocharger will be done by the MGU-H as we know from professional sources (Renault). Cylinder cutting will not impact on the load balancing mechanism for the tubo IMHO.

Any thought as to what would be done with excess energy if electrical storage is maxed out and the turbo needed modulation to limit boost?

It would be directed into the MGUK.

Still don’t get it. Here’s the situation; electrical storage is maxed going into the corner. The driver is on the throttle heavy but short of flat out, i.e. feathering the power output. Exhaust heat is overdriving the turbo so the MGU-H applies a load to modulate the impeller speed. The resulting electrical energy can’t go to the charged-to-the limit battery and seemingly the driver doesn’t want the MGU-K messing with his finely balanced power output. I’ve assumed that the MGU-K would be limited to adding to crankshaft power only under full throttle which could be mistaken.

If the MGU-H is to serve as an alternative to a waste gate, it needs someplace to sink energy. Perhaps resistor banks a bit before the diffuser.