Oktanilukua

Oktanilukua is the octane rating used to describe a fuel's resistance to knocking during combustion in internal combustion engines. It is a standard way to classify gasoline and other petrol fuels and to inform engine design and fuel selection.

Measurement and scales vary by region. In many markets, octane ratings are expressed as octane numbers, typically the Research Octane Number (RON). In the United States and a few other places, the Motor Octane Number (MON) is used, and many fuels are labeled by the AKI, or Anti-Knock Index, which is the average of RON and MON (AKI ≈ (RON + MON)/2). In Europe, labels often reflect RON values, with common numbers such as 95 and 98. European and international standards, such as EN 228 for gasoline, govern how octane ratings are determined and reported.

Usage and significance vary with engine design. Higher octane values allow higher compression ratios and advanced ignition timing, which can improve efficiency and power in suitable engines and reduce the risk of knocking under heavy loads or high temperatures. Vehicle manufacturers specify the minimum octane rating required for optimal operation, and using a fuel with an appropriate oktaniluku helps maintain performance and protection of the engine.

See also: Octane rating, RON, MON, AKI, EN 228. Ok taneiluku is the Finnish term for octane rating and is used in consumer labeling and regulatory contexts in Finland and other Finnish-speaking markets.