Gasoline brand refers to the type of gasoline used for transportation. The most common ones are No. 90, No. 93, and No. 97. Since January 2012, the gasoline brands have been “No. 90, No. 93, and No. 97.” It is proposed to be revised to "No. 89, No. 92, No. 95".
Origin:
1. Principle of detonation
The so-called detonation is the compressed oil or gas mixture, before the spark plug ignites, because The high heat generated by the movement of gas molecules caused by the compression stroke is ignited, forming a so-called auto-ignition phenomenon. Then the spark plug ignites the compressed oil or gas mixture again, causing two high-explosive fireballs to collide violently in the combustion chamber, resulting in a fire like a knock on the door. The "click, click, click" sound. Knocking is related to the selection of fuel. If the fuel is selected correctly, even if the engine compression ratio is increased, knocking will not occur.
2. Knocking and Octane Number
When knocking first occurs, compare the conditions of the mixture of isooctane and n-heptane. If knocking occurs The condition timing is exactly the same as the test condition of 97 parts isooctane and 3 parts n-heptane, so the octane number of this test oil is 97. So, when we talk about 90, 93, and 97 unleaded gasoline, its octane number is actually just a comparison value.