Development Of Oil-Gas Separator For Diesel Engine

The Air-oil Separator is a the most important component of the diesel engine crankcase ventilation system,its purpose is to separate the oil from the blowby gas, that is to reduce the pollutants in the blowby gas. As diesel engine emission regulations more and more strict, the blowby gas accounted for the proportion of the discharge of pollutants is bigger and bigger,and The higher separation efficiency requirements for The Ari-oil Separator.This paper mainly do works on design a labyrinth Air-oil separator for the natural ventilation system of a certain type of diesel engine,the labyrinth type Air-oil separator integrated on the cylinder head cover occupy less space of diesel engine, and in the subsequent emission after the upgrade, but also can be used as a pre separator. The labyrinth type oil and gas separator was developed based on the CFD flow field simulation calculation, and the optimal scheme was selected through simulation calculation, and the experiment was carried out to verify the simulation. The main contents include :(1) Initial scheme of design a labyrinth of Air-oil separator, with AVL- fire software CFD numerical simulation scheme of initial, get the internal flow field of the separator, import and export pressure difference(98k Pa), oil droplets movement and separation efficiency(91.9%).(2) By using different grid density model to calculate the initial plan of the Air-oil separator, select the appropriate grid density to calculate the subsequent optimization scheme.(3) Optimization of the design of the 4 kinds of oil and gas separator program and simulation calculation. The results show that the separation efficiency increases with the decrease of the flow area of the small holes. According to the results, select the import and export pressure difference 230 Pa, separation efficiency of 98.47% of the program 5 as the best program. Finally, the calculation results of different gas channeling flows in the program 5 show that the inlet and outlet pressure difference and separation efficiency of the separator are decreased with the decrease of the gas flow rate.(4) Through bench test to verify the performance of the separator, the test result is: the Blow-by oil content of 2 g/h or less, crankcase pressure of 0.53 k Pa, reached the design target. Calculated value compared with the test results, there is a difference, but the trend is consistent, CFD simulation can be applied to the oil and gas separator design and development stages of CFD to optimize scheme, shorten the development cycle.