The basic principle of selecting air filter isthe rated air inflow of the air filter must be higher than the one when the engine operates in the rated speed and rated power, which means the biggest air inflow of the engine. At the same time, within the allowance of the installing space , it is necessary to use big volume and big flow air filter appropriately, it is good for reducing the air filter resistance and increase the ability of store dust and prolong the maintenance cycle.

The biggest air inflow when the engine operate s in the rated rotating speed and rated load is related with the following:

1.  The displacement of the engine

2.  The rated rotating speed of the engine

3.  The inhaling form of the engine. Because of the function of the booster, the air inflow of the booster will be far larger than the natural type air insuction