Why do Diesel engines have that distinctive sound to them when compared to gasoline engines?
In: 2497
Here’s the simple concept most of these are skipping that ELI5 wouldn’t understand, there’s a basic but interesting bit of physics that allows a diesel to operate.
If you take a volume of air the size of a beach ball, and in less than 0.04 seconds (not 4 seconds) you squeeze that air to the size of a golf ball it’s going to get super heated from all the loose air molecules getting suddenly and roughly squeezed together very tightly. Basically a lot of friction in those air molecules in that short time span make a sudden burst of heat.
That’s the basis of how diesels work, at the precise moment that air is super heated it sprays in diesel fuel in a fine mist. Think like a perfume bottle on steroids.
Diesel in liquid form is hard to light on fire where gas has fumes that are explosive.
Well if you mist diesel it actually becomes more explosive than the same amount of gas.
The knocking that an older diesel makes is basically a combination of poorly timed combustion when it’s cold, these bigger valves all rattling back and forth, the mechanical fuel injectors have to work hard to spray diesel into a chamber that is at 300-500 psi, think how it’s harder to pump up a bicycle tire with a hand pump when the pressure get up to 30-45psi. Now imagine pumping into something at 500psi 325 times a minute and that just to idle. For one cylinder most diesels are 6.
Also another reason for the “characteristic diesel sound” is the layout of the engine. Most diesels are 6 pistons and cylinders in a straight line
OOOOOO
Most car engines can be inline 4
OOOO
V8
OOOO
OOOO
V6
OOO
OOO
If you find an older Jeep or ford truck with an inline 6 it’s going to have a similar sound minus the rattle of the diesels.
And with technology things are getting quieter and more powerful, I had a 2015 Ford F-350 for a while that was whisper quiet but could tear it’s own rear end out under a load. Some new chevys are so quiet the turbocharger whistling is all you hear from the exhaust
Latest Answers