What is the density standard of 95-octane gasoline?

[Virgil]

Under standard atmospheric pressure, the density of 95-octane gasoline is 0.737g/ml, which is only an approximate value. Density is affected by temperature, and the general gasoline density refers to the density at 15.6 degrees Celsius. Generally speaking, the higher the gasoline octane number, the higher the octane value and the better the anti-knock performance. For example, 95-octane gasoline contains 95% isooctane and 5% n-heptane. The fuel grade can be determined based on the engine's compression ratio. Cars with an engine compression ratio between 8.6-9.9 should use 92-octane gasoline. If the compression ratio is higher, 98-octane gasoline should be used. However, with the application of some new technologies, the fuel grade cannot be determined solely by the compression ratio. High compression ratio engines can also be tuned to use lower-grade gasoline because, besides the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Occasionally using the wrong gasoline grade only requires switching back to the correct grade after consumption. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles designed for low-grade gasoline, using high-grade gasoline will not cause damage, but the increase in octane value will change the fuel's ignition point, leading to delayed combustion in the engine. This means the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles designed for high-grade gasoline, using low-grade gasoline can cause engine knocking. Because the octane value is too low, the gasoline's ignition point decreases, causing it to ignite prematurely during the compression stroke. If combustion occurs before the spark plug ignites, resistance will be generated during the upward stroke. This resistance will make the engine run very unstably. If the knocking is imperceptible, it only increases noise without significant damage to the engine. However, if the knocking is noticeable, it indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring. Considerations for selecting gasoline: Choose gasoline with appropriate volatility based on the car's operating environment. Gasoline with good volatility makes cold starts easier and allows the engine to warm up smoothly. However, if the volatility is too high, it can easily cause vapor lock in the fuel lines, preventing the fuel pump from delivering fuel normally and causing the engine to stall. Selecting the right gasoline grade is crucial. Generally, the manufacturer's recommended gasoline grade is printed on the inside of the fuel filler cap, and you should follow this recommendation. If the label states: "Use 92-octane or higher," then both 92-octane and 95-octane gasoline can be used, but they should not be mixed. If the label states: "Use no less than 95-octane," then only 95-octane or 98-octane gasoline can be used, and 92-octane gasoline should not be used. A higher gasoline grade is not always better. The engine's compression ratio needs to match the gasoline grade. If a low-compression engine uses high-grade gasoline, although it can reduce engine knocking, it will alter the ignition timing, leading to increased carbon deposits in the cylinders and affecting the engine's lifespan over time. If a high-compression engine uses low-grade gasoline, the engine is prone to knocking, accelerating the wear and tear of engine components.

[RuthAnn]

As a veteran driver with over a decade of experience, I recall that the density standard for 95-octane gasoline ranges between 0.72 and 0.77 grams per cubic centimeter, measured at 20 degrees Celsius. This standard comes from the national GB 17930 specification. While no one usually pays attention to the exact numbers when refueling, the density does affect actual fuel consumption calculations. For example, higher-density fuel is slightly heavier, so the same volume of fuel might take you farther. In summer, when it's hot, the density decreases a bit, and in winter, when it's cold, it increases. This impact is minimal because gas stations adjust to ensure compliance. My own car has been running on 95-octane fuel for seven or eight years, and the density fluctuations have been negligible. The key is its high octane rating, which keeps the engine running smoothly, improves fuel efficiency, and reduces carbon buildup. If you're concerned about economy, there's no need to obsess over density—just choose reputable gas stations for hassle-free refueling.