Completely the opposite. Less effient engines needs more cooling than higher effient ones.
mercedes will disagree. the merc is the most efficient achiveing 50 percent thermal efficiency. and they have the biggest air intakesCompletely the opposite. Less effient engines needs more cooling than higher effient ones.
They can disagree whatever they want, this is thermodynamics.
it's not neccessarily true. here fuel efficiency rules, imagine situations as follow:
Uhm thermal efficiency is work divided by energy available in fuel rather than heat extracted in combustion.amho wrote: ↑24 Feb 2018, 22:41it's not neccessarily true. here fuel efficiency rules, imagine situations as follow:
engine A extracts 5000 kj from m(g) fuel and it has thermal efficiency of 0.6.
engine B extracts 1000 kj from the same m(gr) fuel and has thermal efficiency of 0.5.
heat rejection in engine A is 2000 kj and heat rejection in engine B is equal to 500 kj.
work (power) in engine A is 3000 kj and in engine B is 500 kj.
so u can see that engine A while has a higher fuel efficiency & power it also rejects more heat.(engine A has a better combustion efficiency).
https://drive.google.com/open?id=12ycBt ... pZKd_hbSsL
check it: (http://energyeducation.ca/encyclopedia/ ... efficiency)Mudflap wrote: ↑24 Feb 2018, 22:53Uhm thermal efficiency is work divided by energy available in fuel rather than heat extracted in combustion.amho wrote: ↑24 Feb 2018, 22:41it's not neccessarily true. here fuel efficiency rules, imagine situations as follow:
engine A extracts 5000 kj from m(g) fuel and it has thermal efficiency of 0.6.
engine B extracts 1000 kj from the same m(gr) fuel and has thermal efficiency of 0.5.
heat rejection in engine A is 2000 kj and heat rejection in engine B is equal to 500 kj.
work (power) in engine A is 3000 kj and in engine B is 500 kj.
so u can see that engine A while has a higher fuel efficiency & power it also rejects more heat.(engine A has a better combustion efficiency).
https://drive.google.com/open?id=12ycBt ... pZKd_hbSsL
yes Qh is the fuel heating value times fuel mass. It is identical for both engines in your example. Since the first engine extracts 6 times more work from the same quantity of fuel your efficiency numbers can't be right.amho wrote: ↑24 Feb 2018, 23:03check it: (http://energyeducation.ca/encyclopedia/ ... efficiency)Mudflap wrote: ↑24 Feb 2018, 22:53Uhm thermal efficiency is work divided by energy available in fuel rather than heat extracted in combustion.amho wrote: ↑24 Feb 2018, 22:41
it's not neccessarily true. here fuel efficiency rules, imagine situations as follow:
engine A extracts 5000 kj from m(g) fuel and it has thermal efficiency of 0.6.
engine B extracts 1000 kj from the same m(gr) fuel and has thermal efficiency of 0.5.
heat rejection in engine A is 2000 kj and heat rejection in engine B is equal to 500 kj.
work (power) in engine A is 3000 kj and in engine B is 500 kj.
so u can see that engine A while has a higher fuel efficiency & power it also rejects more heat.(engine A has a better combustion efficiency).
https://drive.google.com/open?id=12ycBt ... pZKd_hbSsL
Yes these numbers are too imaginary but I wanted to indicate that having higher thermal efficiency does not neccessarily means less heat ejection. Consider Qh for engine A & B equal to 700 and 500 kj for a given fuel and thermal efficiency of 0.5 and 0.4 respectively then A dumps 350 kj and B does 300 kj. Here in F1 if consider all engine have near the same combustion eff. then the one has better thermal efficiency it dumps less heat.Mudflap wrote: ↑24 Feb 2018, 23:08yes Qh is the fuel heating value times fuel mass. It is identical for both engines in your example. Since the first engine extracts 6 times more work from the same quantity of fuel your efficiency numbers can't be right.
Not imaginary, they were objectively wrong.amho wrote: ↑24 Feb 2018, 23:59Yes these numbers are too imaginary but I wanted to indicate that having higher thermal efficiency does not neccessarily means less heat ejection. Consider Qh for engine A & B equal to 700 and 500 kj for a given fuel and thermal efficiency of 0.5 and 0.4 respectively then A dumps 350 kj and B does 300 kj. Here in F1 if consider all engine have near the same combustion eff. then the one has better thermal efficiency it dumps less heat.
I don't want to elongate chat but I didn't say anything about different fuel and flow, read once again carefully. ByeMudflap wrote: ↑25 Feb 2018, 00:13Not imaginary, they were objectively wrong.amho wrote: ↑24 Feb 2018, 23:59Yes these numbers are too imaginary but I wanted to indicate that having higher thermal efficiency does not neccessarily means less heat ejection. Consider Qh for engine A & B equal to 700 and 500 kj for a given fuel and thermal efficiency of 0.5 and 0.4 respectively then A dumps 350 kj and B does 300 kj. Here in F1 if consider all engine have near the same combustion eff. then the one has better thermal efficiency it dumps less heat.
Since we are debating F1 engines what is the point of comparing engines of different fuels or different flow rates ?
DFX's statement was spot on.
Which one is the one car makers like to advertise though? Brake thermal or indicated?Tommy Cookers wrote: ↑25 Feb 2018, 00:11well I've drawn back many times from saying this ........
thermal efficiency is not another name for overall efficiency of a heat engine
(we don't need telling that a heat engines job is to turn heat into work)
thermal efficiency is the efficiency of transformation of heat into work in the combustion chamber and not beyond it
(which too many wrongly insist on calling combustion efficiency)
but to allow harmony and understanding to flow .....
thermal efficiency can reasonably be called indicated thermal efficiency
and overall efficiency can reasonably be called brake thermal efficiency
simple !