Internal Combustion Engines for Dummies

cutaway view of pistons

We're back mining the mother lode of good ol' eHow today in search of yet another Dumbass of the Day. In this case, we've found a repeat offender. Not only is today's freelancer a Dumbass, the site itself is a paragon of dumbassery. The topic on which Jennifer Fleming held forth is "How to Calculate Compression Ratio and PSI,"¹ but the jackasses of Demand Media file this misinformation under — get this — "Business." Given that misclassification, it's no wonder the topic ended up addressed by someone who wouldn't know an internal combustion engine if it hit her in the butt. Look at what she said to her wide world of readers:

"Engines must intake air to perform and they need to increase the pressure within the manifold to realize greater performance. This additional intensity is measured in pounds per second inch and is known as PSI."

How can one person make so many mistakes in two sentences? Well, that's what self-appointed freelance writers hungry for eHow's fifteen bucks did time after time; one of several reasons why eHow has long been the laughingstock of the internet. Let's check out a few of the things she got wrong:

"Engines must intake air.." Holy cow! Jennifer, you dumbass, "intake" isn't a verb. (Internal combustion) engines must take in air... "...they need to increase the pressure within the manifold to realize greater performance." Well, no, they need to increase pressure within the cylinder to create those little explosions that drive the pistons  This isn't to "increase performance," it's because a compressed fuel-air mixture is more explosive than one at ambient pressure - but that's physics, and physics is science, and science is hard PSI does not stand for "pounds per second inch": WTF is a "second inch"? PSI stands for "pounds per square inch," and is a measure of pressure. God help us if you ever have to explain what a kilopascal is...

Fleming then went on to "explain" how to calculate compression ratio... hah. We swear, the office dog is far smarter than this Dumbass of the Day. The dog's only problem is that she can't type because she doesn't have thumbs -- otherwise she might be a freelancer for eHow!

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   ehow.com/how_8782967_calculate-compression-ratio-psi.html

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DD - ENGINES