Blow-by gas recirculation device for internal combustion engine

A blow-by gas recirculation device for an internal combustion engine, the blow-by gas recirculation device including a vacuum pump that serves as a negative pressure source for a brake booster and is usable also for recirculation of blow-by gas to an intake passage, the blow-by gas recirculation device comprising:

• a PCV device configured to recirculate blow-by gas staying inside of a crankcase to the intake passage;
• a ventilation shortage region determination unit configured to determine whether or not an operational region of the engine is an operational region in which the ventilation flow rate of the blow-by gas staying inside of the crankcase by the PCV device is short;
• and
• a brake negative pressure determination unit configured to determine whether or not a brake negative pressure of the brake booster is secured,
• wherein the vacuum pump ventilates the blow-by gas staying inside of the crankcase only when the ventilation shortage region determination unit determines that the operational region of the engine is the operational region in which the ventilation flow rate of the blow-by gas staying inside of the crankcase by the PCV device is short, and furthermore, the brake negative pressure determination unit determines that the brake negative pressure is secured.