Can I Add 98 Octane Gasoline When 95 Octane Is Not Completely Used Up?

[OIris]

95 octane gasoline should not be mixed with 98 octane gasoline. Occasionally adding the wrong gasoline grade only requires switching back to the correct grade after use. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles designed for lower octane gasoline, accidentally using higher octane gasoline will not cause damage, but the increase in octane rating will change 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 designed for higher octane gasoline, using lower octane gasoline can cause engine knocking. Because the octane rating is too low, the gasoline's ignition point decreases, causing it to ignite prematurely 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. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates serious engine issues, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to engine seizure. In addition to checking the recommended gasoline grade in the vehicle's manual, you can also find it on the fuel tank cap. Typically, 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, those between 10.0-11.5 should use 95 octane gasoline, and those with higher compression ratios should use 98 octane gasoline. However, with the use of new technologies, the compression ratio alone cannot determine the required gasoline grade. High-compression engines can also be tuned to use lower octane gasoline due to factors like ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the gasoline grade, the higher the octane rating 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.