TERS : Thermal Energy Recovery System

[noname]

Have a look at the famous Wright_R-3350 aero engine with single stage axial turbines used for turbo compounding. That application is now 65 years old and it probably was the commercially most successful application of turbo compounding ever done to piston engines. F1 will not be too far behind 1945 technology when they start their own lead application. This is why I'm confident that the F1 designers will at least look at axial turbines for efficiency reasons. If you set your objectives too low you will not be successful.

There is one, not that small, difference between R-3350 and road car turbocharger - size. Tip clearances are not scaling down linearly, and they are big source of losses in efficiency.

And there is also problem with finding matching compressor, within the rules defined by FIA, which were set to prohibit already existing technologies.

However, to be clear, I have no doubts axial turbine will be (or rather was/is) taken into consideration. I just do not see it as the preferred way to go, but that's just my opinion.

As for sub-system efficiencies used in estimation(s). You can have compressor with peak efficiency ~80%, MGU having 96-97%. Overall I think 90-100kW is what can be expected as max compounding power in 2014.

[WhiteBlue]

Thank you for showing us some of the critical development issues. It will be interesting how real world F1 engineers will solve those. It is nice that we could work out the potential of the TERS/HERS recovery with a pretty good accuracy. 90 kW is a remarkable figure and if they can pull this off it would be a development that would make a difference in the automotive world.

[noname]

it would be a development that would make a difference in the automotive world.

If "road relevance" would be taken into consideration I think ACO rules are much closer to reality. Especially developments in power management could be very interesting.

[WhiteBlue]

it would be a development that would make a difference in the automotive world.

If "road relevance" would be taken into consideration I think ACO rules are much closer to reality. Especially developments in power management could be very interesting.

But we are not talking ACO here. This is about F1 and thermal energy recovery. I believe that Gilles Simon and Jean Todt did an exceptionally good job with the 2014 formula. The 2013 version would have even been better.

[xpensive]

...
I believe that Gilles Simon and Jean Todt did an exceptionally good job with the 2014 formula. The 2013 version would have even been better.

Why that xperience will serve Gilles Simon in good stead for the 2014 Red Bull engine.

[noname]

This is about F1 and thermal energy recovery.

Got your point, but... both series allows thermal recovery. I bet machines will not be much different. Except maybe power level and the ones coming from more freedom provided by ACO.

I think whoever is interested in this kind of technologies should look at what's happening in endurance racing.

[peanutaxis]

We know that necessity is the mother of invention. Many things have filtered through to road cars from F1, but, I submit, that this only happens when there is FREEDOM. You need freedom to invent novel ideas, otherwise, like the current KERS, it is rather more just a prescription

I reckon that they should have no limit on the amount of heat or kinetic energy recovery systems.

This would give the engineers free reign on designing avant-garde systems which, only when given this freedom, would produce novel ideas which could push technology forward.

[Tommy Cookers]

The reason there's a limit to the power/capacity of system called KERS and TERS is that there are no rules forcing such systems to recover the energy types that their names proclaim.
Such rules would be almost impossible to write, and would be impossible to police.

KERS is in part engine driven, TERS can clearly be driven by deliberate combustion downstream of the cylinders.
Both are infringements of the engine capacity limits, this could not be ignored if KERS or TERS were unlimited and engines were designed around this, also such engines would be freaks utterly unrelated to road engines.

Hybrids exist only because the California laws forced them to exist (for zero TAILPIPE emissions in cities, not zero actual emissions) . Our lovely European lawmakers want lots of complicated expensive European cars to be sold, via pretending that our world will be saved by such cars because they have a bit of KERS, thus enforcing hybrids by the back door.

A proven everyday way of avoiding the need to have such fakery in our cars (and avoiding paying the extra cost) is not to buy 200 bhp engines to do a 40 bhp job, and to use our brains more and our brakes less.
(a 70 bhp hybrid is relatively economical largely because it is 'only' 70 bhp)

The real way to recover thermal energy is to heat/boil water as BMW have shown in cars (but steam hasn't the F1 image).

Much of our electricity has for 20 years come from such a combined cycle, which is giving overall efficiencies of up to 60% , eg after (gas) turbines have used all the pressure available to them to generate electricity, the leftover hot gas can be dumped or used to heat feedwater in a coal-fired power plant (saving a lot of coal).

Turbines (eg as in turbocharger) recover presure energy, not thermal energy as such.
(turbochargers promote efficiency essentially by allowing downsizing, saving on friction and pumping losses as appropriate)

[peanutaxis]

Tommy,

Eh? It's my understanding that KERS is only allowed to harvest energy under braking, is limited in the amount of power it can deliver, and in the amount of energy (power x time) it can deliver per lap. So such rules do exist and are policed! I'm not suggesting that there should be no rules at all, I'm suggesting that the rules should be written so that you can harness as much waste energy as you please.
TERS, if it were to be introduced would be limited in only being able to harness waste energy. In fact, there are specific rules regarding the mapping of engines after the teams were found to be throttling their engines in corners when NOT accelerating.

So long as KERS and TERS are limited in only harvesting waste energy there is no problem, teams could be given free reign to design novel systems to harvest all that waste energy and put it to good use.

[Tommy Cookers]

Harvesting energy under braking is not the same as harvesting energy from the brakes.

What actually stops the engine being run in a way that drives the generator when the driver is off-throttle and on-brake ?
The engine can easily provide a controlled and modulated power flow on the over-run without any difference in the rpm pattern, it's very desirable, as it is much less disruptive of the driver's braking job than genuine KE.
What is the over-run anyway, is there a rule that says no braking can ever be used unless the driver is wholly off-throttle ?
Why wouldn't one want to do something better than wholly genuine KE recovery ?

The rules have made it thus.
If wholly genuine KE recovery was wanted the rules would require the brakes to drive generators directly.

More than post has told me that such part fake KE recovery is standard (originated by Renault?)


Regarding recovery via exhaust turbines, how can the turbine only recover genuine waste energy ?
Essentially a turbocharger doesn't run on (genuine) waste energy, it runs by creating a back pressure (that it puts to very good use).
A turbine is a fluid-mechanical device driven by pressure difference (like a piston), not a magic device that turns heat as such into work/power
Additionally there's many ways in which the turbine can be deliberately fed either temporarily or not , and ultimarely it would come down to philosophical debate.
The practicalities of policing drive the rules (sooner or later)

Rulemakers have a bad record of closing gates in advance, so they have chosen to limit the size of the gates that could be opened.
This limit is also supportive of the road relevance aspect (that is to brainwash us Europeans into going hybrid).

The TE aspect is because normal road driving doesn't work KERS, but the plan is still to greenwash expensive European cars (the world won't be saved via 250 bhp road cars just because they have a turbo driven hybrid system as validated by F1 exposure)

Otherwise please explain how you would make sure that only KE and TE are recovered.
If you have such a (practicable) TE recovery device you can truly save the world.

Of course when they name something TER(S) they mean recovering thermal energy and turning it into mechanical energy via electrical energy via mechanical energy .........
A heat pump is a TE device that actually recovers TE

[peanutaxis]

Oh crap, yeah, you're right, it's different to harvesting it from the brakes, you use it as a brake.

"What actually stops the engine being run in a way that drives the generator when the driver is off-throttle and on-brake ?"

I think the FIA supplied Microsoft ECU for one!

[peanutaxis]

Unsticky. Clearly I killed this thread! Lol.

[Tommy Cookers]

TE can transparently be recovered by the catalytic dissociation of some fuels eg Methanol (into Carbon Monoxide and Hydrogen) using heat from coolant and exhaust.
The engine runs on a mix of these gases and (other) Methanol, on combustion the gases give more heat than their source Methanol contained.
The efficiency gain is about 10-15% at full power, and about 30% at low partial power (power reduction is possible without throttling, controlling the gas fuelling allowing super-lean running instead).

[riff_raff]

I propose that such a device should be called a "SCERS".

One may argue that an exhaust gas driven generator is not truly a "Thermal Energy Recovery System". I believe the exhaust turbine converts the momentum of the exhaust gas mass into rotational force.

The one part of the car that I can think of which comes closest to a true TERS is the radiator. It transfers the heat energy contained in the engine coolant to the passing airflow mass, thus increasing its velocity and momentum. That momentum is then transferred to the car as the air mass is ejected out of the exit duct.

Maybe a more apt name for an exhaust gas turbine generator would be a "Supplemental Chemical Energy Recovery System" or SCERS. Since in reality that is what it is doing. It is just recovering the chemical energy released during combustion that all the other devices ahead of it missed.

[Tommy Cookers]

It is said (quite rightly) that a power recovery turbine in the exhaust stream of a naturally-aspirated engine will reduce the volumetric efficiency because of the raised exhaust pressure needed for recovery.

This effect was clearly designed in to the famously economical cruise of the Wright Turbo-Compound, reducing throttling, at about 0.15 bar boost in cruise the recovered power was almost equal to the power delivered from the pistons.
Cruise was achieved by lowering rpm (hence very low boost) with very lean mixture and coarse 'overdrive' propellor pitch; the CR being only 5.0 - 6.7 (to allow 1.1 bar or more boost for takeoff etc), the exhaust energy was high.

In 99.9% of our (spark ign) road driving we reduce the VE (and thermodynamic efficiency) by using the accelerator pedal to throttle the engine's air supply.
Mr Fiat makes everyday engines that use (via complex variable valve motion) massive recirculation of exhaust gas to allow power reduction without throttling, giving improved efficiency.

Doesn't an electric PRT in an NA engine achieve a similar effect (with fixed valve motion) ?

By modulating the electrical load we can have unthrottled efficient partial power to the road with simultaneous power recovery, or unthrottled efficient full power to the road without recovery.

all this potential thanks to Mr FIA mandating the MGUH for 2014 !

that is, If the MGUH is grafted onto our 2.4 litre NA V8s

BTW those 8 speed transmissions could help here