Knocking
knocking Knocking : knocking is sharp metallic sound,similar to rattling of hammer which is produced in the internal combustion engine owing to immature ignition of air gasoline mixture . →thus due to this there is huge loss of energy and it causes damage to piston & cylinder. →a mixture of petrol vapour and air acts as a fuel in an internal combustion engine. →in the down stroke of the piston ,a mixture of gasoline or petrol vapour & air is drawn from carburetor into the cylinder & on stroke mixture is compressed . →the ratio of the original volume of the fuel mixture to that of final volume obtained after the compression is called as the compression ratio . →efficiency of the engine is depend on this comprssion ratio , higher the C.R higher the efficiency of the engine. →due to the presence of some constituents in the gasoline the rate of oxidation increases & fuel air mixture get ignited instantaneously ,produ