Filter filtration efficiency test

The weighing method is a widely used testing technique for detecting the filtration efficiency of the "three filters" in engines. Given the rapid development of modern engine technology and increasingly strict environmental regulations, higher requirements have been put forward for the performance of the "three filters" of engines (filtration accuracy, filtration efficiency, and service life). The weighing method for testing filtration efficiency can only provide a qualitative understanding of filtration efficiency and cannot offer quantitative analysis information. This traditional weighing method can no longer meet the development requirements of filtration technology.

In the early 1990s, filter manufacturers in Europe and America had adopted the advanced particle counting method instead of the weighing method to test the filtration efficiency of oil filters and fuel filters, achieving the analysis information of filter efficiency from qualitative to quantitative, which met the requirements of key technologies of modern engines. Such as the requirements for the cleanliness of gasoline engine electronic fuel injection systems, diesel engine high-pressure common rail electronic control technology, fuel injection systems, and lubrication systems.

The tiniest leakage of the filter can be detected by observing a sudden drop in the particle separation efficiency at a certain level with a multi-channel testing device. In the filter itself, these leaks that are difficult to verify by gravimetric analysis will only be detected when the differential pressure value is very high.

For the performance test of engine air filters, the weighing method (ISO 5011-2000) is still adopted at home and abroad at present. An absolute filter is installed in the test system to collect the dust that has passed through the filter under test. At this time, the efficiency of the air filter is the ratio of the total amount of dust filtered by the filter under test to the weight of the dust added to this filter. This method only measures the weight of the dust that penetrates the filter, but cannot provide information about the size of the contaminated particles. Furthermore, in many cases, the accuracy obtained by this testing method is insufficient, to the extent that it is impossible to distinguish the differences among various filters.