What does knock resistance mean?
3 Answers
Knock resistance refers to gasoline's ability to resist knocking when burning in an engine, which is a primary indicator of gasoline's combustion performance. Knocking is caused by abnormal combustion of gasoline in the engine. Here's an extended explanation: Introduction to 95 and 92 gasoline: Generally, so-called 95 and 92 unleaded gasoline refers to their octane rating, hence 95 gasoline has better knock resistance than 92. Introduction to octane rating: Octane rating is just a relative indicator, not actually mixed solely with n-heptane or isooctane. Therefore, some fuels blended with other additives can have octane ratings exceeding 100 or even negative values.
Anti-knock performance, simply put, is the ability of vehicle fuel to resist knocking. I only learned about its importance after buying a car. For example, if gasoline burns too early or too violently in the engine cylinder, it produces a knocking sound. This not only makes the car shake and lose power but also damages internal engine components. Like me, I once used lower-grade fuel to save money, resulting in loud engine noises. The mechanic said it was caused by knocking, costing me repair money. High anti-knock fuels, such as those with 95 or 98 octane ratings, burn smoothly and protect engine lifespan. When choosing fuel, always refer to the owner's manual for the recommended grade—following it is the right way to go, saving you a lot of hassle and avoiding malfunctions. Additionally, seasonal changes can affect fuel performance. In hot summers, knocking is more likely, so I make sure to use higher-grade fuel.
Decades of driving experience have taught me that anti-knock quality is a fuel's ability to resist detonation. If fuel ignites uncontrollably during engine compression, it not only causes knocking sounds but also accelerates wear on piston rings and other components. In my younger days, I foolishly used improper fuel, resulting in severe engine knocking that cost me a fortune in repairs. Different vehicles with varying compression ratios require different octane ratings - older cars especially need to use the recommended fuel grade to prevent knocking. Good anti-knock properties ensure smoother engine operation, better power output, and slightly lower fuel consumption, making long-distance driving much more comfortable. You can assess a fuel's anti-knock performance by observing startup noise and acceleration smoothness. At the first sign of abnormality, change the oil or get it checked promptly to avoid minor issues escalating into costly repairs.
