A qualified oil filter must comply with the original design of the engine cylinder pressure, oil temperature, flow rate, viscosity, and vehicle usage conditions, and consider the comprehensive balance of the filter element quality.
1. Pressure drop flow characteristic test: Measure the pressure drop flow curve of the filter assembly with a specified viscosity of engine oil.
2. Characteristic test of filter element bypass element: Measure the pressure drop bypass flow curve of the filter element. When the pressure drop through the filter element is low, in order to limit the amount of unfiltered oil, the bypass element allows for a small amount of oil leakage below the specified opening pressure drop; When the filter element is completely blocked, all flow can be bypassed without exceeding the specified pressure drop.
3. High pressure drop and high temperature characteristic test: used to test the high pressure drop experienced by the oil filter during operation (especially when the filter element is blocked). In addition, the filter element is also affected by the high temperature of the engine oil. The ability of the filter element to withstand high pressure drop without damage should be tested under simulated high temperature conditions.
4. Filter life and filtration efficiency test: The particle counting method is used to determine the service life of the filter element. During the test, a relationship curve between pressure difference test time or pressure difference ash weight is drawn to achieve the test time at 75% of the designed opening pressure of the bypass valve, or the weight of pollutants, to indicate the service life of the filter element.
5. Accumulated efficiency test: When using the gravimetric analysis method to determine the service life of the filter element, the test time or pollutant capture amount shall be evaluated based on the pressure difference at the end of the test.
6. Hydraulic pulse fatigue test: During use, the oil filter should be subjected to the fluctuation pressure of the engine cooling state. During the test, use the prescribed pulsating oil pressure and cycle 1000 times to determine the pressure resistance of the filter housing, sealing ring, and filter element to high pressure fluctuations.
7. Vibration resistance fatigue test: After installing the oil filter assembly, simulate the frequency and amplitude of resonance caused by the vibration surface of the engine or installation structure, maintain the specified oil pressure, and cycle 10 million times to determine the absence of small oil leaks or fatigue damage performance.