Article: What is an octane rating and what does it mean?

June 13, 2018

What is an octane rating cetane rating and what does it mean?

Jeff Glucker Motor Authority May 12, 2018


You pull up to the pump and you are presented with a few choices, and we're not talking about different fuel types here. We're talking, of course, about octane ratings.

Those are large figures at the fueling station, and you know if you press the higher one you're going to spend more money. Why is that and what does is all mean? Jason Fenske from Engineering Explained is here to teach us about octane ratings, and their diesel cousin, the cetane rating.

An octane rating is a scale to show you the knock resistance of a given quantity of fuel. Knock resistance relates to the amount of compression the the fuel can take before it ignites. The greater the compression allowed then the greater the knock resistance, and a higher octane rating is earned. Initially, the octane rating scale was created on a 0-100 metric. Today, with various racing fuels, you can find octane ratings over 100.

Cetane is a rating applied to diesel fuel. Here we're not looking at knock resistance but rather the ignition delay of the fuel. It's similar to knock resistance but it's ....

Click here to read Jeff's complete article at the Motor Authority Web Site.

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