PCV system for internal combustion engine

摘要

A PCV system for an internal combustion engine that can suppress occurrence of preignition due to oil inflow into a cylinder is provided. A path switching valve is controlled so that blowby gas flows via a bypass passage, in a preig occurrence region. Thereby, path pressure loss increases, a PCV flow rate is decreased, and blowby gas can be passed through a separator with a high collection efficiency. As a result, an oil takeaway amount can be reduced, and occurrence of preignition due to cylinder oil inflow can be suppressed.

主权项

1. A PCV system for an internal combustion engine, comprising:
a PCV path that allows a crankcase of an internal combustion engine and an intake passage of the internal combustion engine to communicate with each other, and allows blowby gas in the crankcase to pass therethrough; a bypass passage that is connected in parallel to the PCV path; a valve that is provided between the PCV path and the bypass passage, and changes a flow path of the blowby gas between the PCV path and the bypass passage; a separator that is provided in the bypass passage; and control means that controls the valve so that the blowby gas can flow into the bypass passage when the internal combustion engine is operated in a predetermined load range, pressure detecting means that detects pressure in an inside of the crankcase, wherein the control means includes bypass control means that controls the valve so that the blowby gas can flow into the PCV path side when the pressure detected by the pressure detecting means is a predetermined value or more, in a case in which the valve is controlled so that the blowby gas flows to the bypass passage, wherein the control means includes enriching means that makes an air-fuel ratio of the internal combustion engine rich in a case of performing the control by the bypass control means.