BLOW-BY GAS RECIRCULATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

This blow-by gas recirculation device for an internal combustion engine is provided with a vacuum pump which serves as a negative pressure source for a brake booster, and which can also be used to recirculate blow-by gas to an intake passage. The present invention is provided with: a positive crankcase ventilation (PCV) device for recirculating, to the intake passage, blow-by gas in a crankcase; an insufficient-ventilation-area determination means for determining whether an operation area in which the flow rate of ventilation of the blow-by gas in the crankcase by the PCV device is insufficient is present; and a brake-negative-pressure determination means for determining whether the brake negative pressure for the brake booster is ensured. The present invention is configured such that the vacuum pump is used to ventilate the blow-by gas in the crankcase only when it has been determined that an operation area in which the flow rate of the ventilation of the blow-by gas in the crankcase by the PCV device is insufficient is present, and it has been determined that the brake negative pressure is ensured. Accordingly, opportunities for contact between the blow-by gas and engine oil are reduced, and oil deterioration is inhibited.