Changan Eado can use 92 octane gasoline, and 95 octane gasoline is also acceptable. This gasoline grade is recommended in the official vehicle user manual for this car. In addition to checking the appropriate gasoline grade in the vehicle user manual, the Changan Eado also has it indicated on the fuel tank cap, which can be checked there as well. 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 octane gasoline, those between 10.0-11.5 should use 95 octane gasoline, and if the compression ratio is higher, 98 octane gasoline is recommended. However, with the application of some new technologies, the gasoline grade cannot be solely determined by the compression ratio. A high compression ratio can also be tuned to use lower octane gasoline because, apart from the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, the higher the gasoline octane number, the higher the octane value and the better the anti-knock performance. 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline contains 95% isooctane and 5% n-heptane. If the Changan Eado 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 octane gasoline, using higher octane gasoline will not cause damage, but the increase in octane value 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, and the actual feedback will be poorer performance. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. Because the octane value is too low, the gasoline's ignition point decreases and it may ignite prematurely during the compression stroke. If combustion occurs before the spark plug ignites, resistance will arise during the upward stroke. This resistance will make the engine run very unstably. If it's mild knocking, it only increases noise and does not significantly damage the engine. However, if there is noticeable knocking, it indicates severe engine conditions. The vibration not only affects driving stability but can also cause abnormal wear on the pistons and cylinders, and in severe cases, even cylinder scoring.
