TERS : Thermal Energy Recovery System

[Tommy Cookers]

on the circuit it would always be disadvantageous to operate below 10500 rpm (in effect this is throwing away allowed fuel ?)

[WhiteBlue]

on the circuit it would always be disadvantageous to operate below 10500 rpm (in effect this is throwing away allowed fuel ?)

I'm not sure how that will play out. Carrying less fuel will be one of the options to gain a competitive advantage. The prime strategy will be pursuing efficiency on all levels. Since the fuel use is limited every increase in efficiency will give you more power and maxing power is still the main design objective. So it will depend of the efficiency at a particular operating point of the engine whether that operating point will be preferred. Without any doubt you need partial power while you are cornering. I'm having my doubts that using excessive revs and wasting fuel will be the best strategy for medium and slow corners.

[Tommy Cookers]

BTW GP racing motorcycles had 2 opposite rotating crankshafts for decades (unrelated to gyroscopic torques)
(4 cylinder disc-valved 2 strokes) they needed 2 crankshafts geared, opposite rotation is inevitable (also cancels 2nd order vibrations)

conventional (ie transverse) motorcycle crankshafts rotate in the same sense as the wheels
both (wheels and engine) resist roll, then produce gyroscopic reactions (to roll on corner entry) favourable in direction (ie yaw moment contributing to the required cornering yaw)
in steady cornering their yawing displacement hinders roll by producing adverse rolling moments (from engine and wheels)
this requires a greater angle of lean (predicted and proven eg the Wilson-Jones (Royal Enfield) paper 192?)
so the 2 strokes as above should be better mid-corner (as would machines with reverse engine rotation)
the conventional configuration seems helpful to corner exit
wheel inertia is a major factor (hence the historical tendency to smaller diameters)

longitudinal crankshafts have always been suspect in racing motorcycles (for drive/inertial torque effects mostly)
gyroscopic reactions to pitch are destabilising in yaw, however there is no effect in cornering
(the MotoCyzsc C1 (longitudinally oriented and staggered but dynamically like a 2 stroke 'squareV' 4) makes sense, cancelling adverse gyroscopic reactions as above and improved corner entry and mid-corner)

the 1964-5 Honda F1 car had a transverse engine (motorcycle-style)
(it must have developed some favourable and unfavourable rolling moments according to the direction of cornering)
there is surely some such argument for rotation (of turbo/PRT /(integral ?? MGUH) on a transverse axis ?
these effects could be significant in (most) slow corners (little dowforce and high yaw rates)

no doubt practical factors eg packaging and standardisation will supervene

[WhiteBlue]

BTW GP racing motorcycles had 2 opposite rotating crankshafts for decades ... no doubt practical factors eg packaging and standardisation will supervene

What is the significance of that observation for TERS?
BTW Ringo calculated the amount of net gain from the 2014 TERS system at 84 hp. Nice to have I would say because it comes entirely out of otherwise wasted energy. This is a main reason why the over all 2014 power train will reach unmatched brake thermal efficiency and fuel savings.

[Tommy Cookers]

are you saying that Ringo's calculations include the effects on crankshaft power (ie power from pistons) of subjecting the exhaust flow to the turbine load equivalent to 84 bhp recovered ?

[WhiteBlue]

are you saying that Ringo's calculations include the effects on crankshaft power (ie power from pistons) of subjecting the exhaust flow to the turbine load equivalent to 84 bhp recovered ?

No, he calculated the power for the turbine (124 hp) and the compressor at peak power (40 hp). If you take away the compressor 40 hp the remaining 84 hp is for the MGU-H to turn it into electricity. This electric power would be added to the gear box and ultimately to the rear wheels by the MGU-K. You can interpret it as the as the wasted thermal and kinetic power if you process the same air flow with a NA engine. At least that is a very good approximation because the turbo engine compared to a NA engine with the same air flow would have slightly different losses for friction, the radiators and the intercoolers. I believe that you can neglect those differences because they would be almost a magnitude smaller.

[Tommy Cookers]

let me try to ask this simple question in another (simple) way

we could regard the engine as having a two part turbine, one 40 hp part fixed to the compressor only and the other 84 hp part coaxial but fixed to the MGUH only, such that eg at 10500 engine rpm the turbo is matched exactly to the engines operating point, the compressor using the exact power from the 40 hp turbine, and eg the 84 hp turbine rotates but draws no power from the exhaust flow because the generator field is zero ie there is no load on the turbine
the exhaust system pressure upstream of the turbine has a certain level at any time

now the generator field is increased to fully load the 84 hp turbine, which rotates at the same speed but now fully powers the generator mechanically (eg delivering about 70 hp to the rear axle)

does the exhaust pressure upstream of the turbine increase when the 84 hp turbine has the generator load increased from the '0hp' to '84hp' level ??
if it does then more compressor power is required to maintain massflow
if it does not, then please explain
(how the pressure drop across the turbine gives 84 hp, but there is no pressure increase above the turbine)

or, ....... is Ringo's model a whole engine model (piston and turbines)?, or otherwise covers this factor ?

[pgfpro]

IMO when the MGUH goes to full load say 84HP it will move to the right of the turbine map with a increase in pressure.
Example:

Blue dot compressor only with MGUH disable
Red dot compressor and full load 84HP from MGUH

The 2014 F1's turbo's turbine are going to be very efficient, plus on the large size to keep the engines delta p numbers at a high value around +6. This will allow when the MGHU is activated to give some breathing room based on the extra load from the MGHU to generate its power.
IMO this will drop the engines delta p to around +1 to no more then a -2
At even -2 engine delta p this is still a decent number and should be able to make great power.

[WhiteBlue]

we could regard the engine as having a two part turbine, one 40 hp part fixed to the compressor only and the other 84 hp part coaxial but fixed to the MGUH only, such that eg at 10500 engine rpm the turbo is matched exactly to the engines operating point, the compressor using the exact power from the 40 hp turbine, and eg the 84 hp turbine rotates but draws no power from the exhaust flow because the generator field is zero ie there is no load on the turbine the exhaust system pressure upstream of the turbine has a certain level at any time
now the generator field is increased to fully load the 84 hp turbine, which rotates at the same speed but now fully powers the generator mechanically (eg delivering about 70 hp to the rear axle)
does the exhaust pressure upstream of the turbine increase when the 84 hp turbine has the generator load increased from the '0hp' to '84hp' level ??
if it does then more compressor power is required to maintain massflow
if it does not, then please explain
(how the pressure drop across the turbine gives 84 hp, but there is no pressure increase above the turbine)
or, ....... is Ringo's model a whole engine model (piston and turbines)?, or otherwise covers this factor ?

The engine program computes both the engine and the turbo. Please have a look at the thread. You cannot analyse it the way you suggested. The turbine and compressor power calculations are based on the delta p and delta T of the mass flows. He also makes a number of sensible assumptions on the engine side and adds some input parameters. You better have a look for yourself.

The main point is that usually nobody would fit such a huge turbine to a compressor because it is slow reacting and in a standard design you would have to let the excess power escape from a waste gate. But in the electric compounding design you can exploit the excessive waste energy potential for electricity generation. Having the power values for both compressor and turbine from their enthalpy gives us the exact energy flow that gets extracted from the exhaust gas. That is the beauty of the model: You can eliminate the compressor power that you input into the air flow. What remains is the net energy out of the exhaust gas. And that is exactly the 84 hp that are not extracted by the comparable NA engine with the same mass flow. I cannot explain it any better. Please ask Ringo for details.

[WhiteBlue]

IMO when the MGUH goes to full load say 84HP it will move to the right of the turbine map with a increase in pressure.
Example:
Blue dot compressor only with MGUH disable
Red dot compressor and full load 84HP from MGUH

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.

[Tommy Cookers]

@pgfpro
thanks for your view on exhaust pressures with and without recovery

to me they suggest that recovery costs about 1% of engine power 'lost' to the crankshaft
and another 'loss' (equvalent to about 2% of engine power) is the need for more compressor power (to maintain massflow)
(there are tiny effects eg on useable CR etc also)
this suggests that there is a notional cost of 3% of engine power in the process of recovering 84 hp
(assuming that the equations take account of these 'losses' when predicting recovered power)
remembering that the electrical recovery route is about 92% efficient input shaft-to-output shaft
this gives about 77 notionally free hp from recovery (ie 12% of engine power)
(about the same as my estimate in another thread (based on Wright Turbo-Compound data)
presumably the increase in compressor work (and charge heating) is a major factor limiting the ultimate extent of recovery power
presumably eg a further 84 hp recovery is not possible ?

because of the constant fuel rate, these engines have very strong self-regulation of turbo speed
(this is very useful, reducing the disadvantages of high turbo inertia)
above 10500 engine rpm (once the turbo rpm is correct) they are flat-rated in both engine power and recovery power

as I said before, the rules are clever, also, when it's all working, the electrical hardware side should be congratulated
overall, it's quite difficult, but not too difficult

[pgfpro]

IMO when the MGUH goes to full load say 84HP it will move to the right of the turbine map with a increase in pressure.
Example:
Blue dot compressor only with MGUH disable
Red dot compressor and full load 84HP from MGUH

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.

[WhiteBlue]

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.

[Nando]

Formula 1 delays introduction of electrical power for the pitlane

http://totalf1.com/full_story/view/4350 ... cal_power/

[Holm86]

So if they are willing to make compromises that must mean that the 2014 engine is at the moment still on. There would be no point in making compromises if they allready know that they will postpone the 2014 engine regulations anyways??