Honda Power Unit Hardware & Software

[kasio]

[...]


Cannot be that You think they have broken 2nd law of thermodynamics on those 2sux diesels? well If they could then F1 also can!
besides You only need about 48.5% and not even 50% to break 1000HP.

Gosh...that remark was sarcastic. Of course no one on this planet breaks that law.

And... 48.5% bte to break 1000 HP?
Please show us your calculation, and how high the energy content (MJ/kg) of "your" fuel is.

Really Should i?
http://www.engineeringtoolbox.com/fuels ... d_169.html
(46476(kJ/kg)*100kg)/3600sec = 1291kW
120kW+1291kW*0.485(efficiency)=746kW*1.34(kw to HP) ~ 1000HP

[Tommy Cookers]

your 120 kW unless sustainable aka continuously available at the max fuel rate - is false accounting

and it is conventional to use the LCV (lower calorific value) - not the HCV (higher) as you seem to have ?, and your linked source seems to show
heating fuels eg gases are marketed by the HCV, but heating system efficiencies are based on LCV (systems with recovery exceed 100% efficiency)
some net sources erroneously tabulate HCVs as LCVs
scientists may wish to use the HCV, but this will not help to reconcile anything

[Abarth]

[....]

Really Should i?
[...¨]

Yes, and Tommy Cookers already showed the flaws of your reasoning (thanks TC, btw).

[Abarth]

your 120 kW unless sustainable aka continuously available at the max fuel rate - is false accounting [...]

It is false even if sustainable, because it is not coming from nowhere but from compunded "exhaust heat", and therefore has to be included into the bte calculation.

[kasio]

your 120 kW unless sustainable aka continuously available at the max fuel rate - is false accounting

and it is conventional to use the LCV (lower calorific value) - not the HCV (higher) as you seem to have ?, and your linked source seems to show
scientists may wish to use the HCV, but this will not help to reconcile anything

Right if You talk about sustained power You need to take those 120kW from same fuel burned. In that case i agree You would need more than 50% thermal efficiency. But we are talking about max power which some people deem to be impossible without 50% efficiency.
As about calorific value as i mentioned before - properties of fuel, burning process and energy exerted in burning depends on pressure and temperature. Besides LCV is not a sure loss its just method when You do not recover heat energy from water below 150C. So in general if You lose some energy always(as in case of LCV) does not mean You have to throw it out of equation.
So in general even if You ignore that these calorific values cannot be used directly to fuel burned in engine - You still cannot ignore that 150C water is still doing work - its steam! ( which You suggest to ignore in LCV case)

Edit. i am now far off my knowledge! But here is more simple explanation of what i tried to say - from wikipedia:
"The difference between HHV and LHV definitions causes endless confusion when quoters do not bother to state the convention being used.[3] since there is typically a 10% difference between the two methods for a power plant burning natural gas. For simply benchmarking part of a reaction the LHV may be appropriate, but HHV should be used for overall energy efficiency calculations, if only to avoid confusion, and in any case the value or convention should be clearly stated."

[Tommy Cookers]

fwiw I believe that eg the 54.6% or 55.2% etc given for B&W is based on LCV/LHV because that is the (mandated) standard for engines even today
the fact that some heating systems eg do mandatorily claim over 100% seems to me to support this view
btw other systems eg Ricardo's have discounted more heat than the convention does
btw the difference between LHV and UHV etc is particularly large with eg gas fuels and eg methanol as some MAN/B&Ws now use

yes I assume that other areas of activity use a 'fundamentalist' interpretational system re. efficiency determination

it's irrating (to me) that we have little idea what the sustainable turbine-recovered power is for any of the F1 engines
in 1950s aviation the total (crankshaft+turbine recovery) torque was directly monitored at takeoff to check turbine (and human) health outcomes

[PlatinumZealot]

Hello Kaiso. These calculations have been beaten to death in so many threads over the past three years. No need to go over them here. Use the lower heating value of the fuel to find how much horsepower the engine sends through the crank without battery assist.

With battery assist it gets a bit blurry because the MGUK has a power limit so there is some overlap as to how much of that power comes from the MGUH and how much is from the Battery.

[godlameroso]

To further confuse things, the power in the battery is harvested from the engine moving the car, and then stopping the car. So the original point is still about energy extracted from fuel, as the electromachines recover energy from the consumption of fuel. The battery is not charged in the pits according to the regulations.

[wuzak]

your 120 kW unless sustainable aka continuously available at the max fuel rate - is false accounting

and it is conventional to use the LCV (lower calorific value) - not the HCV (higher) as you seem to have ?, and your linked source seems to show
scientists may wish to use the HCV, but this will not help to reconcile anything

Right if You talk about sustained power You need to take those 120kW from same fuel burned. In that case i agree You would need more than 50% thermal efficiency. But we are talking about max power which some people deem to be impossible without 50% efficiency.

The point I think some are trying to make is that the 48.5% efficiency is with some degree of compounding - ie the MGUH feeds back directly to the MGUK.

So, if the MGUH provides 60kW to the MGUK there is only an additional 60kW that the MGUK can provide. The power would be:
60kW+1291kW*0.485(efficiency)=686kW*1.34(kW to HP) ~ 920HP

In full power mode the battery provides an external energy supply to the MGUK and the MGUH (driving the turbo). It is not sustainable.

[wuzak]

To further confuse things, the power in the battery is harvested from the engine moving the car, and then stopping the car. So the original point is still about energy extracted from fuel, as the electromachines recover energy from the consumption of fuel. The battery is not charged in the pits according to the regulations.

But that is not the fuel that is being burned at the time you are calculating the BTE. It could have been 1 second, 1 minute or 1 hour ago.

[godlameroso]

One could argue that the electrical energy couldn't be captured without having had burned the fuel to produce heat, and kinetic motion in the first place.

If the battery power was being supplied by a fictional electric roadway then you wouldn't count it in the efficiency equation because it's an external power supply.

[Wazari]

3. Where is this plate located? I don't think I understand your concept.

The perforated plate is located above the crown with a spacer. The perforations would allow hot air to come through while the flame stays above the perforations. (Don't know why a flame does not pass through a perforated plate or slows)

I guess it would possible but structural integrity of a spacer would be my primary concern. Here's food for thought, strictly hypothetically speaking, how about a piston with a specially designed flat chamber under the crown, with multi directional channels entering and exiting the chamber and the effect it can have in the over efficiency of the suck, squeeze, bang, blow cycles.

[godlameroso]

3. Where is this plate located? I don't think I understand your concept.

The perforated plate is located above the crown with a spacer. The perforations would allow hot air to come through while the flame stays above the perforations. (Don't know why a flame does not pass through a perforated plate or slows)

I guess it would possible but structural integrity of a spacer would be my primary concern. Here's food for thought, strictly hypothetically speaking, how about a piston with a specially designed flat chamber under the crown, with multi directional channels entering and exiting the chamber and the effect it can have in the over efficiency of the suck, squeeze, bang, blow cycles.

Would this chamber be between the crown and wrist pin? Would it's effect then be on the piston rings?

[Wazari]

The perforated plate is located above the crown with a spacer. The perforations would allow hot air to come through while the flame stays above the perforations. (Don't know why a flame does not pass through a perforated plate or slows)

I guess it would possible but structural integrity of a spacer would be my primary concern. Here's food for thought, strictly hypothetically speaking, how about a piston with a specially designed flat chamber under the crown, with multi directional channels entering and exiting the chamber and the effect it can have in the over efficiency of the suck, squeeze, bang, blow cycles.

Would this chamber be between the crown and wrist pin? Would it's effect then be on the piston rings?

Yes and would it? Remember, this is strictly hypothetical...........

[wuzak]

One could argue that the electrical energy couldn't be captured without having had burned the fuel to produce heat, and kinetic motion in the first place.

Yes, but how much fuel?

You expend several seconds of fuel at 100kg/h on the straights to only recover a fraction of the braking energy, most of the remainder goes into the atmosphere as heat.