Hacker News Reader

Comment by rkuodys | Hacker News Reader

I personally wonder how much more the 33% would be if we had continued the focus on ICE. I believe there is no business case anymore to invest significantly in advancing technology, if everyone wants a new shiny toy.

View on HN

There's not much more you can get out of current fuel blends. Methanol is potent but very expensive to mix, the even more expensive nitromethane is so powerful it strains the science of metallurgy and thus is some of the most dangerous stuff to handle, and hydrazine is so energy dense but so unstable it's used as rocket fuel. Porsche's E-Fuel is just barely more efficient than gasoline because of the density at point six megajoules a kilogram, versus point five four for one hundred octane gasoline.

The major issue is parasitic drivetrain loss from having to push the cylinder which pushes the cam which turns the flywheel which friction fits against the clutch which friction fits against the transmission flywheel which turns dozens of metal gears which rotates the driveshafts. Direct drive implementations where the engine's output shaft is mated directly to the axle are much more efficient and have been used in massive ships, but are entirely impractical for use in passenger vehicles. There's the Otto, Atkinson, Wankel, Scuderi and diesel cycles for liquid fuel combustion, and all have tradeoffs leaving them competitive with eachother instead of having a clear best solution thanks to everything else required to transfer the power from the initial combustion.

In short, we've hit the mechanical engineering dead end for massive efficiency gains with ICEs. It's all chemical from here, and thus gets much more expensive to run.

Modern ICEs are already insanely sophisticated, in pushing the boundaries with all kinds of tiny tricks, just to get a small percent extra. There is only that much you can get by changing the valve timing, freevalve, compression ratio, air boosters, electric turbos, fuel injection methods, mixture ratio, how the fuel get sprayed most efficiently into the chamber, predictive hill cruise control, balancing rods and whatnot. Everything has been tried and the improvements for each new trick is only marginal.

Something more radical has to be done about the entire crankshaft and a 4 piston design. Believe me, lots of smart people have tried that as well, for many decades. Because the payoffs if you did find something are huge.

There are lots of YouTube channels needing into all of this. Engineering Explained is a good one if you want to understand the level of how advanced modern engines really are.

The theoretical limit is 50% according to Wikipedia, but there's other factors being optimized for as well aside from efficiency:

https://en.wikipedia.org/wiki/Engine_efficiency#:~:text=Mode....

It’s been 200 years and untold amounts of R&D money thrown at this incredibly lucrative, huge industry. It’s not budging much beyond what it is.

That’s where competitive motorsports development helps:

Mercedes has devised an engine that achieves more than 50 percent efficiency.

https://www.roadandtrack.com/motorsports/a15049580/mercedes-...

ICE is kind of a dead end, you convert energy from chemical to thermal to mechanical and every conversion is lossy. You want to use chemical energy directly instead, like some kind of "hydrocarbon/air cell" and we don't know how to do it. At least not with mixed hydrocarbons.

Reply on news.ycombinator.com