The working condition of the air filter and when it needs maintenance or replacement can be determined by the following methods:
In theory, the service life and maintenance interval of an air filter should be measured by the ratio of the gas flow through the filter element to the gas flow required by the engine. When the flow rate is greater than the flow rate, the filter operates normally; When the flow rate is equal to the flow rate, the filter should be maintained; When the flow rate is less than the flow rate, the filter cannot be used anymore, otherwise the operating conditions of the engine will deteriorate. The situation is getting worse and even unable to work.
In practical work, when the air filter element is blocked by suspended particles and cannot meet the air flow required by the engine, the engine's operating state will appear abnormal, such as a roar, slow acceleration (insufficient intake air volume, insufficient cylinder pressure), weak work (too rich mixture leads to incomplete combustion), relatively high water temperature (combustion continues when entering the exhaust stroke), and smoke becomes thicker when the exhaust accelerates. When these symptoms occur, it can be judged that the air filter is clogged, and the filter element should be promptly removed for maintenance or replacement.
When maintaining the air filter element, pay attention to the color changes on the inner and outer surfaces of the filter element. After dust removal, the outer surface of the filter paper is clear, and the inner surface is bright. The filter element can continue to be used; If the outer surface of the filter paper loses its original color or the inner surface darkens, it must be replaced.