What is the Difference Between Gasoline and Diesel?
1 Answers
Five key differences between diesel and gasoline: 1. Volatility: Gasoline is highly volatile, while diesel is less volatile. 2. Mixing with air: Gasoline mixes easily with air due to its high volatility, whereas diesel does not mix as readily. This makes diesel combustion less efficient, leading to incomplete burning and the emission of black carbon particles, which is why diesel vehicles often produce black smoke and have a stronger odor. 3. Energy content: Gasoline is lighter and consists of smaller molecules, with hydrocarbon compounds containing about 8-10 carbon atoms, while diesel has 12-15 carbon atoms. More carbon atoms mean more energy released upon complete combustion, so diesel provides higher energy per unit volume compared to gasoline. 4. Combustion method: Gasoline molecules are smaller and more reactive, with a lower ignition point. In gasoline engines, an ideal air-fuel mixture is compressed to about 10:1 and ignited by a spark plug. Diesel, with its higher carbon content, requires more air and is harder to ignite with a spark plug, so it uses a compression ratio of 15-18:1 to compress the diesel-air mixture (compression raises temperature) until it combusts. 5. Emission characteristics: Gasoline burns at high temperatures, and incomplete combustion leads to partial dissociation of compounds, producing carbon monoxide, hydrocarbons, and nitrogen oxides. Diesel engines have more air but poorer mixing, leading to oxygen-deficient zones that produce soot, which is why older diesel trucks emit thick smoke during rapid acceleration or cold starts.
