An engine with a high compression ratio requires which type of fuel?

An engine with a high compression ratio requires fuel with a high octane rating that burns slowly. High compression ratios increase the temperature and pressure in the combustion chamber, which can lead to premature ignition known as "knocking" or "pinging." This knocking occurs when the air-fuel mixture ignites ahead of the spark plug’s firing due to excessive pressure.

High octane fuels are designed to resist this pre-ignition and allow for a more controlled and efficient combustion process. They burn more slowly and evenly, which is critical for maintaining performance and preventing damage to the engine. In contrast, fuels with a low octane rating may ignite too early under the high pressure conditions of a high compression engine, leading to knocking and decreased efficiency.

Thus, high octane fuel plays a crucial role in the operation of high compression engines, making it the appropriate choice for optimal performance and engine longevity.