Should the Hybrid Odyssey Use 92 or 95 Octane Gasoline?

[AlainaLee]

Hybrid Odyssey should use 92 octane gasoline, as this is the fuel grade officially recommended in the vehicle's user manual. In addition to checking the appropriate gasoline grade in the user manual, the Hybrid Odyssey's fuel cap will also indicate the recommended grade. You can usually determine the suitable gasoline grade based on the engine's compression ratio. Vehicles with an engine 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. If the compression ratio is even higher, 98 octane gasoline is recommended. However, with the application of new technologies, the compression ratio alone cannot determine the gasoline grade, as high compression ratios can also 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 gasoline grade, 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 Hybrid Odyssey occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower octane gasoline, accidentally using higher octane gasoline will not cause damage. However, 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 lower octane gasoline can cause engine knocking. Due to the significantly lower octane number, the gasoline may ignite prematurely during the compression stroke before the spark plug fires. This premature ignition creates resistance during the upward stroke, making the engine run very unevenly. If the knocking is mild, it may only increase noise without obvious engine damage. However, severe knocking indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in extreme cases, cylinder scoring.