Oil mist separator

An oil mist separator comprising:

• a housing which is provided with an inflow port and an outflow port for blow-by gas and a drain pipe through which oil is discharged;
• and
• a plurality of oil separating parts being mounted in the housing and disposed in series in a flowing direction of the blow-by gas to separate oil mist in the blow-by gas, the plurality of oil separating parts including at least a first oil separating part and a second oil separating part arranged on a downstream side of the first oil separating part,
• wherein the plurality of oil separating parts each comprise:
• a partition wall, which defines a chamber formed for the respective oil separating part in the housing, is provided with nozzles for jetting out blow-by gas;
• and
• a collision part with which the blow-by gas jetted out from the nozzles collides;
• wherein the partition wall of the first oil separating part is arranged in a vertical direction in the housing,
• wherein the partition wall of the second oil separating part is arranged in a horizontal direction in the housing so that a flow channel is formed between the partition wall and a bottom part of the housing,
• wherein the drain pipe is provided in the chamber of the first oil separating part, and
• wherein the nozzles of the partition wall of the second oil separating part also serve as passages for discharging the oil separated by the second oil separating part toward the drain pipe.