What is the Difference Between Gasoline and Diesel?
3 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.
I've been driving a diesel truck for deliveries for ten years, and gasoline and diesel are really not the same thing. Gasoline cars start quickly and accelerate smoothly, they can even start in cold weather without issues, but they consume more fuel, and frequent refueling in the city can be annoying. Diesel, on the other hand, has strong power and handles heavy loads effortlessly. Because it uses compression ignition, there are no spark plugs—it ignites spontaneously under pressure, so the engine is heavier and noisier, but it's fuel-efficient and saves money on long trips. The downside is that in winter, you need to preheat it to prevent gelling. Chemically, gasoline is light and volatile, with additives to prevent knocking; diesel is thick with heavier molecules and has strong self-ignition properties. Nowadays, electric vehicles are stealing the spotlight, but diesel still has advantages in freight transport, while gasoline is much more convenient for daily use.
I've been using gasoline for my family sedan for several years, and the difference from diesel is quite clear. Gasoline requires more frequent refueling, but it starts quickly without shaking, and the car is quiet and comfortable; diesel saves money with less refueling, but it starts slowly in cold weather, and the engine roars loudly. Fundamentally, gasoline ignites with spark plugs, evaporates quickly, and burns cleanly; diesel relies on compression ignition, with high compression ratios and low auto-ignition points. In terms of price, gasoline is usually slightly cheaper, but diesel has longer range and saves money. In practice, gasoline is suitable for city commuting, while diesel is better for highway driving and hauling goods. Be careful not to use the wrong fuel, as it can damage the car. Recently, rising fuel prices have been tough, but you get used to it.
