Why does the Xingyue L require 95-octane gasoline?

[SamuelLynn]

According to the official vehicle manual recommendation, the Xingyue L 2.0T should use 95-octane gasoline, while the 1.5T hybrid version can use 92-octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the Xingyue L also displays this information on the fuel tank cap. Generally, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with a compression ratio between 8.6-9.9 should use 92-octane gasoline, while those with a compression ratio between 10.0-11.5 should use 95-octane gasoline. However, with the application of new technologies, the compression ratio alone cannot determine the required gasoline grade. High compression ratio engines can also be tuned to use lower-octane gasoline due to other influencing factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the gasoline octane rating, the higher the octane number 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 Xingyue L occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade may have the following effects: For vehicles recommended to use lower-octane gasoline, using a higher-octane grade will not cause damage, but the increased octane number may alter the fuel's ignition point, leading to delayed combustion in the engine. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles recommended to use higher-octane gasoline, using a lower-octane grade may cause engine knocking. The significantly lower octane number reduces the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug ignites, resistance will arise during the upward stroke, making the engine run very unevenly. Mild knocking only increases noise without significant engine damage, but noticeable knocking indicates severe engine conditions, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in severe cases.