Should the Han DM use 92 or 95 octane gasoline?
4 Answers
The Han DM should use 92 octane gasoline, as this fuel grade is recommended in the vehicle's official user manual. In addition to checking the appropriate gasoline grade in the user manual, the fuel cap of the Han DM will also indicate the recommended grade. Generally, 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 application of new technologies, the compression ratio alone cannot determine the 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 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 Han DM occasionally uses the wrong gasoline grade, simply switching back to the correct grade after consumption is sufficient. However, long-term use of the wrong grade can have the following effects: For vehicles designed for lower octane fuel, using a higher grade will not cause damage, but the increased octane rating may alter the fuel's ignition point, leading to delayed combustion in the engine. This reduces both the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles designed for higher octane fuel, using a lower 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 is created 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 driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.
As someone who frequently drives the Han DM, I think using 92-octane gasoline is perfectly fine. After all, 92-octane is cheaper, saving about a dollar per liter, which adds up to significant fuel savings over a year. The Han DM is a plug-in hybrid, and its engine mainly works during startup or at high speeds. Since the compression ratio isn’t high, 92-octane is entirely sufficient—it won’t affect the car’s lifespan and still ensures smooth driving. For even better optimization, prioritize charging mode when possible. A full battery leads to lower fuel consumption, which is the smarter choice. There’s no need to blindly opt for 95-octane and incur unnecessary expenses.
When driving the Han DM, I prefer to use 95-octane gasoline. Although it's more expensive, I feel the power response is better, especially when climbing hills or overtaking—the engine's explosive force is stronger, making the drive smoother. However, this isn't mandatory. The official manual states that 92-octane is also suitable, so it depends on personal preference. If you mostly drive on flat roads, using 92-octane is perfectly fine. Since hybrid cars primarily rely on the battery with the engine as a secondary power source, my choice of 95-octane is purely for driving enjoyment. But do be cautious about fuel quality—avoid mixing in substandard gasoline to prevent potential malfunctions.
From a maintenance perspective, sticking with 92-octane gasoline is worry-free and cost-effective. The Han DM's engine is designed for mid-to-low octane fuel, and using 92-octane won't harm components. Frequently using 95-octane may lead to slightly more carbon buildup requiring cleaning. Remember to check the owner's manual which clearly recommends 92-octane for daily use - no need to complicate things with dealership maintenance.
