What are the similarities and difference between gasoline, petroleum diesel, and biodiesel?

Question

follow up question: why cannot we use diesel fuel in a gasoline engine??

Answer 1

Similarities between all three: They are all mixtures of hydrocarbons - carbon chains with hydrogens bonded to the carbons. They are all liquids, flammable, lighter than water, and have negative health effects on humans. Combustion of any of them releases about 19,000 BTUs per pound of fuel and about 3 pounds of carbon dixoide (a green-house gas) per pound of fuel burned.

Differences: Gasoline has more carcinogenic compounds in it, especially benzene, followed by toulene and xylenes. Diesel in current vehicles produces more sulphur dioxide and particulates but clean diesel (required for the 2007 model year) greatly reduces that. Gasoline engines have more power per engine weight and accelerate quicker. Diesel engines are more efficient because they are higher compression (18-23:1 versus 8.5-9.5:1 for gasoline). Gasoline engines are "spark ignition" - spark plug generate an electric arc that ignites the vaporized fuel. Diesel engines are "compression ignition" - the air is heated through compression and the atomized liquid fuel ignites in that hot air.

Diesel versus biodiesel - similar boiling point and flash point ranges. Similar energy content. Biodiesel comes directly or indirectly (reused fryer oil) from plants, often soy or corn. Different smell, like fench fries, to biodiesel. Diesel, "dino-diesel" is from petroleum which is also mostly from plants, but from ones that lived 300 million years ago.

Follow-up Q: Diesel will not vaporize into a gas in the intake manifold of a gasoline engine. This is true for both carburated and fuel-injected gasoline engines. It will go in as a liquid and not make a uniformly explosive mixture needed to propagate the flame front from the spark plug. For lack of an spark ignitable fuel, the gas engine would stop.

Follow-up to the follow-up: Some diesel engines can burn gasoline - the military calls them multi-fuel engines. Don't try it in your Mercedes though. Unless designed for it, the faster burn rate of the gasoline and the lack of lubrication from the diesel (a light oil) can cause problems.

Answer 2

All are fuels for internal combustion engine. Gasoline and diesel are refined from crude oil. Gasoline is further refined. It is a mixture of carbon chains about 8 carbons long. Diesel is a thicker fuel of longer carbon lengths. Biodiesel is a fuel similar to diesel but it is made from plants. Soybeans work well. It smells like popcorn burning, much better than a "bus" smell. A diesel engine differs from a gas engine in that it compresses the air fuel mixture to 22 to 1. The compression heating is what ignites the mix. (no spark plugs). The engine is under much greater compression. It is more efficient than gas.The main difference between the fuels is the higher flash point of diesel. This allows it to be compressed.If gas is put into a diiesel engine it will explode.

Answer 3

Gasoline is what most cars in America run on. Its highly refined petroleum and very combustible. Petroleum diesel is made out of petroleum and not as refined. In fact the oil field in Northern Iraq are almost diesel right out of the ground. Bio-diesel is made from things like freedom fries grease, and cast off donut grease and other more natural products. I offer as a description of the differences the following story... One day at the Abu Gharib prison a motor his both a trailer full of gasoline and an other trailer full of diesel. The trailer full of gasoline exploded but the trailer full of diesel as completely intact below the fill line.