What grade of fuel should the e300 use?
1 Answers
The e300 should use 95-octane gasoline, as this fuel grade is recommended in the vehicle's official owner's manual. In addition to checking the appropriate fuel grade in the owner's manual, you can also find it indicated on the fuel filler cap. Typically, the fuel 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, 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 fuel grade, as high-compression engines can also be tuned to use lower-octane fuel. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, the higher the fuel 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 e300 occasionally uses the wrong fuel grade, simply switch back to the correct grade after the tank is empty. However, prolonged use of the wrong fuel grade can have the following effects: For vehicles designed for lower-octane fuel, using a higher-octane fuel 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 fuel, using a lower-octane fuel can cause engine knocking. Since the octane rating is significantly lower, the fuel's ignition point decreases, 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 unevenly. If the knocking is mild, it may only increase noise without significant engine damage. However, severe knocking indicates serious engine issues, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in extreme cases, cylinder scoring.
