Any mechanical engineers in the haus? Help requested!

[schrodingers cat]

Yes, but what is the conversion rate of the person - Calories in - power out. A human generates a lot of heat.

[Dare]

Yes, but what is the conversion rate of the person - Calories in - power out. A human generates a lot of heat.

Wouldn't know, although I think an engine probably produces more waste heat in comparison.. Humans generally stay under 37 odd degrees.
Can anyone find out a human powerband? Rolling road with a bicycle perhaps...

[jono035]

From memory humans are about 1hp peak for very brief bursts (sprinters etc.) but about 0.1-0.2hp sustained.

I'm guessing that humans are probably less efficient in terms of mechanical work done divided by heat energy out. A sweating human in a breeze could probably dissipate a hell of a lot of energy as heat.

[schrodingers cat]

Correct - an internal combustion engine is only 25 - 30% efficient due to heat rejection.

Just curious because I'm always interested in TOTAL energy cycles. is their a doctor in the house?

I remeber reading once that peanut butter has a higher calorific value than gasoline...

[Real_Wolf]

Yeah, but he was also right, whereas you were wrong. Actually it may have been Indy, in fact I think it was a few of us.

Crank angles ignored, firing order (for cars at the very least, not 100% on inline-4 bikes) is always 1342 except for a couple of random old ford pushrod engines...

What? I didn't say anything about it, it was indy who was arguing for what was it, 1324? Meh, I was just talking to Janis mostly, trying to avoid any conversation which involved indy.

As for the internal combustion engine, curious fact is our most efficient energy in terms of the thermodynamic efficiency is the diesel engine, but its still quite a bit below the carnot engine

[Dare]

What? I didn't say anything about it, it was indy who was arguing for what was it, 1324? Meh, I was just talking to Janis mostly, trying to avoid any conversation which involved indy.

As for the internal combustion engine, curious fact is our most efficient energy in terms of the thermodynamic efficiency is the diesel engine, but its still quite a bit below the carnot engine

Ooookay.
Also, what about the stirling engine? Or the dipping head bird
Edit: Oh the carnot is hypothetical.

[Slyer]

1-3-4-2 bitches. Except for the new crossplane R1 which is 1-3-2-4.

[jono035]

What? I didn't say anything about it, it was indy who was arguing for what was it, 1324? Meh, I was just talking to Janis mostly, trying to avoid any conversation which involved indy.

As for the internal combustion engine, curious fact is our most efficient energy in terms of the thermodynamic efficiency is the diesel engine, but its still quite a bit below the carnot engine

Really? Wow, in that case my memory of the entire conversation is just backwards as hell... My apologies... No where did Indy get to...

Slyer: Interesting, wasn't aware of that, that's a weird crank angle too, to get a big-bang firing order, isn't it.

[bogan]

1-3-4-2 bitches. Except for the new crossplane R1 which is 1-3-2-4.

pffft, whats with all this 3s and 4s BS, the only firing order you need is 1-2 or even just 1!

[avgas]

Correct - an internal combustion engine is only 25 - 30% efficient due to heat rejection.
Just curious because I'm always interested in TOTAL energy cycles. is their a doctor in the house?
I remeber reading once that peanut butter has a higher calorific value than gasoline...

Dunno about that - but I know that Sugar is pretty damn combustible.
Sugar dust makes a good floating explosive membrane.

[avgas]

pffft, whats with all this 3s and 4s BS, the only firing order you need is 1-2 or even just 1!

Or like my old Chevanne
1342,34,1,3,2,1234,1324,1342,1342,142,2,3,1....... .............................

[bogan]

Or like my old Chevanne
1342,34,1,3,2,1234,1324,1342,1342,142,2,3,1....... .............................

bet that had a mean cool exhaust note, kinda like them harleys even?

[Real_Wolf]

lol, thats an awesome firing order.

Lol Dare, yes, the carnot engine is the hypothetical engine where the maximum possible efficiency is observed, due to no process being fully thermodynamically reversible it can not be achieved.

[jono035]

http://en.wikipedia.org/wiki/Scuderi_Engine

Just remembered this from a lecture given a few months ago by one of the Audi high-ups.

Interesting idea really, one of the key aspects that the guy mentioned was that it allows much higher combustion chamber temperatures which are key to efficiency.

Edit: Also a few other neat parts like allowing the fuel to be sprayed directly into the hot pre-compressed charge air without having the hassle of injecting into the combustion chamber. This has some pretty big advantages for predictable fuel-air mixing etc. Their main selling point seems to be the after-top-dead-centre firing...

[bogan]

http://en.wikipedia.org/wiki/Scuderi_Engine

Just remembered this from a lecture given a few months ago by one of the Audi high-ups.

Interesting idea really, one of the key aspects was allowing much higher combustion chamber temperatures which are key to efficiency.

hmmm, I'm guessing the intake valve on the combustion cylinder is still partially open at TDC to give a high enough compression ratio? I'm kinda struggling to see any benifits over the conventional cycle tbh.

Some of my personal favourites are the steam based 6 stroke and the supercharged two stroke (only diesel so far as can't direct inject petrol yet)