What grade of gasoline should be used for the Changan Oshan X5?
1 Answers
All models of the Changan Oshan X5 should use 92-grade gasoline. This gasoline grade is recommended in the official vehicle user manual. In addition to checking the appropriate gasoline grade in the vehicle user manual, you can also find it on the fuel tank cap, which will be clearly marked. Typically, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with an engine compression ratio between 8.6-9.9 should use 92-grade gasoline, those between 10.0-11.5 should use 95-grade gasoline, and those with a higher compression ratio should use 98-grade gasoline. However, with the application of new technologies, the gasoline grade cannot be solely determined by the compression ratio. A high compression ratio can also be adjusted 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. Generally, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. 92-grade gasoline contains 92% isooctane and 8% n-heptane, while 95-grade gasoline contains 95% isooctane and 5% n-heptane. If the Changan Oshan X5 occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower-grade gasoline, using higher-grade gasoline will not cause damage, but the increase in octane number will alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles recommended to use higher-grade gasoline, using lower-grade gasoline can cause engine knocking. Because the octane number is much lower, the fuel's ignition point decreases, causing premature ignition during the compression stroke. If the fuel ignites before the spark plug fires, resistance will occur during the upward stroke. This resistance makes the engine run very unstably. If the knocking is mild, it only increases noise without significant engine damage. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.
