Why is gasoline (octane) better than diesal (cetane)?
Huh - who says?
diesel is usually ignited (except when starting cold) by the increase in pressure and temperature resulting from compression in the cylinder. Gasoline generally requires a spark plug. (unless the cylinder or deposits in the cylinder get so hot they ignite before the spark which is terrible for the engine)
http://www.scribd.com/doc/7292781/Differences-Between-Octane-Number-and-Cetane-Number#scribd
better? That is debatable.
diesel does not have to be refined as much.
Diesel is not likely to explode as easily. Gasoline has a higher vapor pressure, so ignites easier than diesel.
Why is gasoline "better" than diesel? Depends on one's viewpoint and use.
Gasoline, which contains predominantly octane, is considered better than diesel, which contains primarily cetane, for several reasons. Here's why:
1. Combustion Efficiency: Gasoline has a higher flame propagation speed, meaning it burns more quickly and efficiently compared to diesel. This characteristic allows for better performance in spark ignition engines commonly found in passenger cars.
2. Power Output: Gasoline engines tend to have higher power output per unit of engine displacement compared to diesel engines. This is primarily because gasoline can be combusted at a higher compression ratio due to its ability to resist premature ignition, known as knocking.
3. Cold Starting: Gasoline engines have a higher vapor pressure, making them easier to start during cold weather conditions. Diesel engines often require glow plugs or other preheating mechanisms to aid in ignition during low-temperature starts.
4. Emission Control: Gasoline engines equipped with catalytic converters typically have better emissions control, especially in terms of reducing particulate matter and nitrogen oxide (NOx) emissions. Diesel engines, on the other hand, produce higher levels of particulate matter and NOx, requiring additional equipment, such as diesel particulate filters (DPFs) and selective catalytic reduction (SCR) systems, to meet emission regulations.
It's important to note that the choice between gasoline and diesel depends on various factors, such as the desired application (e.g., passenger car, heavy-duty truck), fuel efficiency requirements, and environmental considerations. To gain a more comprehensive understanding of the topic, it's advisable to refer to scientific studies, automotive engineering textbooks, or consult experts in the field of internal combustion engines.