What Octane Gasoline Should the Buick Envision Use?
1 Answers
The Buick Envision should use 92-octane gasoline, as recommended in the vehicle's official owner's manual. In addition to checking the owner's manual for the appropriate gasoline octane rating, you can also find this information on the fuel filler cap. Typically, the gasoline octane 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, 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 use of new technologies, the compression ratio alone cannot determine the appropriate gasoline octane. Engines with high compression ratios 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 Buick Envision occasionally uses the wrong gasoline octane, simply switch back to the correct octane after the tank is empty. However, prolonged use of the wrong octane can have the following effects: For vehicles designed for lower-octane gasoline, using higher-octane gasoline will not cause damage, but the increased octane number can 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 designed for higher-octane gasoline, using lower-octane gasoline can cause engine knocking. The significantly lower octane number lowers 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 may only increase noise without obvious engine damage, but noticeable knocking indicates severe engine conditions. The vibrations not only affect driving stability but can also cause abnormal wear on the pistons and cylinders, potentially leading to severe engine damage such as cylinder scoring.
