We all know that diesel engines need to work efficiently with air and diesel. If the inhaled air contains dust and impurities, it will directly affect the combustion efficiency of the engine, and even increase the wear of the components. So there is an air filter, Xiaobian today from the structure of the air filter to everyone to understand its role, for the future driver friends in the choice of air filter to make a reminder.
The air filter is usually installed in front of the intake pipe of the engine, and the air filter for the truck is divided into dry type and wet type according to the operating environment.
The dry air filter separates the airborne impurities through a dry filter element (such as a paper filter). The filter material is filter paper or non-woven fabric. The filter end cap is made of metal or polyurethane and the outer casing is made of metal or plastic. At the rated air volume flow rate, the original filtration efficiency of the filter element should be no less than 99.5%. Due to the harsh working environment, heavy-duty vehicles must have multiple air filters.
The first stage is a cyclone prefilter (such as blade ring, swirl tube, etc.), used to filter out coarse particle impurities, the filtration efficiency is above 80%, and the second stage fine filter is a microporous paper filter (generally called the main Filter element), its filtration efficiency is over 99.5%. There is also a safety filter element behind the main filter element to prevent dust from entering the engine when the main filter element is installed and replaced, or when the main filter element is accidentally damaged. The material of the safety core is mostly non-woven fabric, and also uses filter paper.
The wet air filter also includes oil immersion and oil bath. The oil immersion type is to separate the impurities in the air through an oil-impregnated filter element, and the filter element material has a metal wire fabric and a foaming material.
The oil bath type introduces the sucked dusty air into the oil pool to remove most of the dust, and then further filters the oil misted air through a filter element wound by the wire, the oil droplets and the stopped oil. The dust returns to the oil pool together.
The filtration efficiency of the paper filter is as high as 99.5%, and the filtration efficiency of the oil bath filter is 95-96% under normal conditions.
When the engine is running, the intake air is intermittent, causing air vibration in the air cleaner housing. If the air pressure fluctuates too much, it sometimes affects the intake air of the engine. In addition, the intake noise will also increase at this time. In order to suppress the intake noise, the volume of the air cleaner housing may be increased, and some partitions may be disposed therein to reduce resonance.
Post time: May-06-2019