What Type of Gasoline Should the Alphard Use?

[DelAaliyah]

The Alphard should use 92-octane gasoline, as this fuel grade is recommended in the vehicle's official owner's manual. In addition to checking the suitable gasoline grade in the owner's manual, you can also find this information on the fuel tank cap, which is usually labeled. Typically, the appropriate gasoline grade 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 higher, 98-octane gasoline is recommended. However, with the use of new technologies, the compression ratio alone cannot determine the appropriate gasoline grade. High-compression engines can also be tuned to use lower-octane gasoline due to factors such as 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. If the Alphard occasionally uses the wrong gasoline grade, simply switch back to the correct grade after the current tank is used up. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles designed for lower-octane gasoline, using a higher-octane grade will not cause damage, but the increased octane rating 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 a lower-octane grade can cause engine knocking. The significantly lower octane rating lowers the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance builds up during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without obvious engine damage, but severe knocking indicates serious engine issues. The vibrations not only affect driving stability but can also cause abnormal wear on the pistons and cylinders, potentially leading to cylinder scoring in severe cases.