What is the Difference Between Gas and Diesel Engines?


How do diesel engines work?

With all the emissions scandals surrounding Volkswagen, Mercedes, Fiat, and even Harley-Davidson, we’ve been talking a lot about diesel engines in the last year, but how many of our readers really understand how diesel engines work compared to gas engines? How many of them really understand how a conventional four-cycle engine works in the first place?

Instead of asking, we’re just going to show you- with more than a little help from this terrific diesel and four-cycle comparison video put together by the gearheads over at CarThrottle. Like them, we’re curious to hear about which of the two concepts you’re a bigger fan of in the comments section- and, no, we’re not terribly interested in discussing how obsolete ICEs may or may not be (save that for the EV posts). Enjoy!


What is the Difference Between Gas and Diesel Engines?

Source | Images: CarThrottle.

About the Author

I've been in the auto industry 1997, and write for a number of blogs in the IM network. You can also find me on Twitter, at my Volvo fansite, or chasing my kids around Oak Park, IL.
  • Eco Logical

    Good video!

    However, it wasn’t mentioned (in the video) that the higher compression ratio in a diesel engine is what causes the Nitrogen Oxides (NOx) emissions, in VW’s case, “FORTY TIMES” (EPA) acceptable levels. NOx creates NITRIC ACID in your lungs causing Asthma, Emphysema, and many other diseases.

    Another thing that should be mentioned is that diesels use “DIRECT INJECTION” (into the cylinder) whereas most gasoline engines use “THROTTLE BODY INJECTION” (into the intake manifold) giving more time for the gasoline to vaporize. DIRECT INJECTION creates more particulate matter since the fuel isn’t mixed as well resulting in an incomplete burn. The tiny carbon fibers that constitute the “particulate matter” lodge in the lungs and can’t be removed by the body. Eventually the lungs “scar over” in that spot resulting in an inability to exchange oxygen. As the scarring increases, it becomes more and more difficult to get enough oxygen into your blood, even though you seem to breath just fine. Eventually, you have to go on oxygen, and then in a short time, you die from asphyxiation. This is identical to what happens with Asbestos fibers that create a disease known as “ASBESTOSIS”.

    In other words, DIESELS KILL PEOPLE !!!

    • Joe Viocoe

      Thank you for the medical summary. Informative.

    • Epicurus

      Jeezus. Thanks for this valuable information.

      Production of new diesel engines should be banned immediately worldwide, and diesel engine cars and trucks should be banned from the roads in 3 years.

      European governments are as much slaves of big corporations as is the American government apparently. Sad.

  • Tim Jonson

    LOL…. I guess this is for millennials or something?

  • Don’t say that too loud- you’ll summon a libertarian.