@veritasium: What is octane rating in fuel? #veritasium #Science #physics #chemistry #octane

Mmann :

Hence why diesel engines don’t use spark plugs. Also why when u put the wrong fuel in ur car it messes it up

iluvmacs :

Wait wait wait. Diesel can withstand compression ratios above 15:1 but octane can’t get that far. How is diesel have a lower octane range?

Wolfgang Thor :

So what’s my 103 octane race fuel?

Danny Boy :

So how are there racing fuels above 100? Are they 110% iso-octane? 😂

_m_b :

Why isn’t the scale psi

Mike :

Labeling gas as “premium” feels like a predatory way of deceiving people into buying a more expensive fuel that they really shouldn’t buy.

Matt :

I wish Derek would come back as the main face of Veritasium again

Todd Sedlak :

It's not just compression, it's a rate of compression. If you pressed that piston down slowly enough, it wouldn't ignite.

..ffhffs :

we can conclude that we should NEVER put gasoline in diesel engine

anonymous :

doesn't ethenol increase octane?

mromkar :

so the less octane in your fuel the better combustion?

Deerhunter40 :

octane 😳 like don tolivers newer album

RMS :

98 RON being 98% isooctane and 2% n-heptane does not hold. Many fuels are > 100 RON and you cannot have more than 100% of anything so forget it. Octane rating is a nonlinear scale were isooctane is given 100 as an arbitrary reference, and n-heptane is given 0. The rating expresses the knock resistance where higher means more resistant but the numeric difference does not really tell by how much in terms of pressure or temperature or anything. Moving from 90 to 100 RON allows for a much larger jump in compression than moving from 80 to 90.

Richárd Horogszegi :

is that really an explosion?

xx :

This is hilarious

Njordr Valravn :

so if there's n-heptane in the mixture, how to make sure n-heptane doesnt explode first in lower compression and trigger combustion toiso-octane?

BeerChemist MikeWayne :

Octane has an octane rating of -20. Be sure to say isooctane.

bobbyjbobbyj :

Isooctane, not octane

𝘑𝘢𝘺𝘤𝘳𝘪𝘮𝘴𝘰𝘯 🪳 :

The more branched it is, the better it can withstand compression.

bdub626 :

Cetane, not octane, is the rating for Diesel. ASTM D613

BeerChemist MikeWayne :

We should also point out it was Kettering who advanced all of this.

Pulsar :

brothernature :

This is so cool

Fran :

I don't understand. Usually diesel engines have a much higher compression ratio than gasoline ones. I was under the impression that, if you wanted to make a gasoline engine more energy efficient, you would increase its compression ratio. So much as to when auto ignition occurs. As is my understanding, this is the opposite of what this video shows. That's why, gasoline engines use spark plugs: you need to lower the compression ratio to a point that the ignition can only be achieved with a spark, and not compression. What am I missing here?

TsweerieN :

I didn't know diesel had an octane rating