Monster combustion engines

[flynfrog]

what is the point of such large piston engines wouldnt a steam or even fuel turbine be more efficient

[nae]

My understanding of the large slow revving ship engines is they burn the cheapest fuel , a kind of sludge thats left over from the rest of the hydro cracking fuel making process.

i am ready to be corrected on that

[flynfrog]

My understanding of the large slow revving ship engines is they burn the cheapest fuel , a kind of sludge thats left over from the rest of the hydro cracking fuel making process.

i am ready to be corrected on that

no that makes sense you need fairly refined oil for a turbine

I also believe most of those big piston diesels are in china where emissions are not an issue

[WhiteBlue]

...I also believe most of those big piston diesels are in china where emissions are not an issue

those are primary engines for comercial vessels like container ships and tankers. so as such they cannot be associated with specific country regulation. the engines are believed to have high thermal efficiency which would indicate that they have a good environmental status. btw, I think that China is making a big push for more environmetally safe equipment lately.

[Ciro Pabón]

Yes, it's the thermal efficiency (or so I read). I quote from the Wiki article on thermal efficiency:

"... a typical gasoline automobile engine operates at around 25% thermal efficiency, and a large coal-fueled electrical generating plant peaks at about 36%. The largest diesel engine in the world peaks at 51.7%. In a combined cycle plant thermal efficiencies are approaching 60%."

[rjsa]

What I remember from my lost thermodynamic knowledge is that slow is efficient.

I'll lack vocabulary in english, but the basic theory on internal combustion engines was lectured considering quasi-static (is this right???) expansion of combustion fumes. The accelerated process had much greater entropy gain.

[bazanaius]

That seems to make sense.

The thing that gets me with the massive ship engines is that they're pretty much identical to a car engine (or any ICE), just BIGGER.

I'd have loved to have been in that design meeting.

[rjsa]

That seems to make sense.

The thing that gets me with the massive ship engines is that they're pretty much identical to a car engine (or any ICE), just BIGGER.

I'd have loved to have been in that design meeting.

Yep, bigger and with direct drive in this kind of application, no gearing involved.

[flynfrog]

Yes, it's the thermal efficiency (or so I read). I quote from the Wiki article on thermal efficiency:

"... a typical gasoline automobile engine operates at around 25% thermal efficiency, and a large coal-fueled electrical generating plant peaks at about 36%. The largest diesel engine in the world peaks at 51.7%. In a combined cycle plant thermal efficiencies are approaching 60%."

petrol turbines with recovery turbines are close to that if not better If I remeber correctly