A compound oil-gas separator was devised, which included the coarse filtration of labyrinthine structure and the fine filtration of filter mesh. An oil-gas separator component performance test bench was further developed, and multiple oil-gas separator schemes were designed by using the orthogonal test design method. Performance tests of multiple schemes were conducted based on the component test bench. Ultimately, a compound oil-gas separator meeting the requirements was designed and its performance was verified through engine test. The results indicate that the factors influencing the overall performance of oil-gas separator are the number of mesh layers, mesh count, filter hole diameter, number of holes, and hole plate spacing in order from strong to weak. Engine test revealed that the separation efficiency reached 92.6% and the pressure loss was less than 3 kPa at a blow-by rate of 300 L/min, which met the requirements of engine use.
