Octane rating of diesel fuel?

[ekrampitzjr]

Okay, gang, here's the kooky (or stupid) question of the day. What would be the octane rating of #2 diesel fuel? My searches on the net have come up with "not available" or "no meaning". I assume that diesel fuel must have some octane rating, however low it might be.

And what would the cetane rating for gasoline, say iso-octane, be?

Thanks.--Ed

 

[cryptokid]

the octane rating for diesel is real low. diesel made my lawnmower ping, so it has to be lower than 87 by far.

 

[Ken2]

Diesel fuel has not been rated for octane. That would be like asking the shoe size of your hat.


Ken

 

[cryptokid]

Diesel and Jet fuel (along with kerosene) have, indeed, terrible octane numbers; typically about 15-25 "octane". They tend to ignite easily from high compression. Their use in a gasoline engine will quickly destroy the engine.

http://www.prime-mover.org/Engines/GArticles/octane.html

[ March 06, 2004, 03:08 PM: Message edited by: rugerman1 ]

 

[Shannow]

Similarly, petrol has a very very low cetane.

 

[mrchecker]

I have a Tecumseh manual that covers dual fuel engines that start on gas and run on kerosene. The big difference (besides the carb) is that the dual fuel engine has a different cylinder head that lowers the compression ratio to 4:1 from 6:1. That's some low octane fuel if it can only stand 4:1 compression without knocking.

 

[SteveD2]

quote:

---

Originally posted by cryptokid:
the octane rating for diesel is real low. diesel made my lawnmower ping, so it has to be lower than 87 by far.

---

I have to ask, why did you put diesel in your lawnmower?

 

[cryptokid]

i just wanted to see what would happen.

 

[Tim]

This may be old new for most, but octane is a name for C-8 hydrocarbon and cetane for C-16 hydrocarbon.

Gasoline has a distribution mostly in the C-9 and under range, while diesel is mostly C-13+.

So you can see there would be little if any overlap between the two.

I like the analogy of the shoe size for your hat!

Tim

 

[nicrfe1370]

quote:

---

Originally posted by Tim:
This may be old new for most, but octane is a name for C-8 hydrocarbon and cetane for C-16 hydrocarbon.

Gasoline has a distribution mostly in the C-9 and under range, while diesel is mostly C-13+.

So you can see there would be little if any overlap between the two.

I like the analogy of the shoe size for your hat!

Tim

---

Anything can have an octane rating. The octane rating as we know it is a liquid's resistance to preignition relative to pure octane, pure octane having an octane number of 100 (as I recall.) You can find the octane number for diesel fuel, but for the most part, no one has a practical need to. The shoe size for your hat comparison is clumsy, if not outright wrong.

 

[Jerry]

I saw a sunoco station in conn. that had 40 listed as octane for diesel.

 

[MNgopher]

The 40 was probably the cetane rating of the Diesel fuel, not an octane reading.

 

[ekrampitzjr]

Way to resurrect an old thread! Found a chart from a US government website that gives both answers:

http://www.eere.energy.gov/afdc/pdfs/afv_info.pdf
(Alternative fuels comparison chart, 2 printed pages)

The octane rating of diesel fuel is 8-15—indeed low. But there is a rating.

The cetane rating of gasoline is 5-20—also indeed low. But again there is a rating.

I had found these in other sources some time back after posing the question, but stumbled across this chart with both parameters just a few days ago.

 

[psudaytona]

The octane is only 8-15?!? Wow.

 

[Shannow]

ekrampitzjr...thanks for the link to the document. I've been after such a thing for a decade or more.

 

[ekrampitzjr]

You're more than welcome, Shannow. Here's another one.

http://www.eere.energy.gov/afdc/pdfs/fueltable.pdf
(General table of fuel properties, 2 pages)

My bad on the previous post; the alternative fuels chart runs 3 printed pages, not 2.

The US government website http://www.eere.energy.gov links to much useful info under the links for fuels and lubricants. Do some exploration and you'll find a lot.

 

[Ducked]

Originally Posted By: ekrampitzjr
Way to resurrect an old thread! Found a chart from a US government website that gives both answers:

http://www.eere.energy.gov/afdc/pdfs/afv_info.pdf
(Alternative fuels comparison chart, 2 printed pages)

The octane rating of diesel fuel is 8-15—indeed low. But there is a rating.

The cetane rating of gasoline is 5-20—also indeed low. But again there is a rating.

I had found these in other sources some time back after posing the question, but stumbled across this chart with both parameters just a few days ago.


Eh?

I might be missing something, but on my screen, octane rating of diesel fuel is listed as N/A. likewise cetane rating of gasoline.

They might have edited/degraded the document, but its still dated 2004.

(Old thread but it came up again recently)