For Example When Your Car Comes Knocking

The word explosion is often associated with devastation, but it really means just a very rapid reaction—so rapid that the surroundings don t have time to accommodate the change. In our modem world, explosions are as common as breathing. The internal combustion engine can generate some several thousand explosions per minute. 

It seems odd that the internal combustion engine has only been around for a century or so while humankind has been making explosions for several thousand years. The explanation, of course, has to do with all 

Another factor is fuel. If the gasoline is of a grade that is better able to withstand the temperatures and pressures within the cylinder without spontaneously igniting, then knock is less likely. A fuel with a high octane rating is formulated to resist burning until it is sparked. 

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