What are the consequences of always using 92 octane gasoline for the Odyssey?

[Allie]

The Odyssey can use 92 octane gasoline. This octane rating is recommended in the vehicle's official owner's manual. In addition to checking the appropriate gasoline octane rating in the owner's manual, the Odyssey also has this information marked on the fuel tank cap. Generally, the octane rating 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, and higher compression ratios may require 98 octane. However, with the use of new technologies, the compression ratio alone cannot determine the required octane rating, as high compression ratio engines can be tuned to use lower octane gasoline. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, the higher the 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 Odyssey occasionally uses the wrong octane gasoline, simply switching back to the correct octane after use is sufficient. However, long-term use of the wrong octane gasoline 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 number can change 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 lower octane gasoline can 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 fires, resistance is created during the upward stroke. This resistance makes the engine run very unstably. Mild knocking only increases noise and does not significantly damage the engine, but severe knocking indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.