Oil separation device for internal combustion engine

A breather system of an internal combustion engine provided with a PCV circuit for returning blow-by gas produced in the internal combustion engine fitted with a supercharger to an intake passage by using an intake negative pressure produced in the intake passage to be used for combustion once again, the breather system comprising,

• a breather chamber provided on top of a head cover of the internal combustion engine and communicating with a breather passage for conducting blow-by gas produced in the internal combustion engine, the breather chamber including a first gas liquid separation chamber extending in a cylinder row direction and communicating with the breather passage, a second gas liquid separation chamber extending in the cylinder row direction along the first gas liquid separation chamber and communicating with an interior of the internal combustion engine via the intake passage, and a communication passage communicating the first gas liquid separation chamber with the second gas liquid separation chamber at one end of the internal combustion engine with respect to the cylinder row direction, the second gas liquid separation chamber including a spiral passage for causing a swirling flow of the blow-by gas in the second gas liquid separation chamber;
• a PCV valve provided in the communication passage for adjusting a flow rate of the blow-by gas;
• and
• a one-way valve provided at another end of the internal combustion engine with respect to the cylinder row direction for expelling the blow-by gas from the second gas liquid separation chamber;
• wherein the spiral passage comprises a lower rib extending upward from a bottom surface of the corresponding chamber provided with the spiral passage and an upper rib extending downward from a ceiling surface of the corresponding chamber, the lower rib and the upper rib crossing each other so as to present a letter X shape in plan view.

A breather system of an internal combustion engine provided with a PCV circuit for returning blow-by gas produced in the internal combustion engine fitted with a supercharger to an intake passage by using an intake negative pressure produced in the intake passage to be used for combustion once again, the breather system comprising,

• a breather chamber provided on top of a head cover of the internal combustion engine and communicating with a breather passage for conducting blow-by gas produced in the internal combustion engine, the breather chamber including a first gas liquid separation chamber extending in a cylinder row direction and communicating with the breather passage, a second gas liquid separation chamber extending in the cylinder row direction along the first gas liquid separation chamber and communicating with an interior of the internal combustion engine via the intake passage, and a communication passage communicating the first gas liquid separation chamber with the second gas liquid separation chamber at one end of the internal combustion engine with respect to the cylinder row direction;
• a PCV valve provided in the communication passage for adjusting a flow rate of the blow-by gas;
• and
• a one-way valve provided at another end of the internal combustion engine with respect to the cylinder row direction for expelling the blow-by gas from the second gas liquid separation chamber;
• wherein the second gas liquid separation chamber includes a spiral passage for causing a swirling flow of the blow-by gas in the second gas liquid separation chamber, and the first gas liquid separation chamber comprises
• a hole portion serving as an oil return hole and a blow-by gas inlet hole formed in a bottom wall of an end of the first gas liquid separation chamber on the other end side of the cylinder row direction, and
• an auxiliary opening for introducing the blow-by gas into the first gas liquid separation chamber, the auxiliary opening being provided in a part of the first gas liquid separation chamber located higher than the hole portion serving as an oil return hole and a blow-by gas inlet hole in a state where the internal combustion engine is mounted on a vehicle and different from an upstream side of a downward flow of oil separated from the blow-by gas.

A breather system of an internal combustion engine provided with a PCV circuit for returning blow-by gas produced in the internal combustion engine fitted with a supercharger to an intake passage by using an intake negative pressure produced in the intake passage to be used for combustion once again, the breather system comprising,

• a breather chamber provided on top of a head cover of the internal combustion engine and communicating with a breather passage for conducting blow-by gas produced in the internal combustion engine, the breather chamber including a first gas liquid separation chamber extending in a cylinder row direction and communicating with the breather passage, a second gas liquid separation chamber extending in the cylinder row direction along the first gas liquid separation chamber and communicating with an interior of the internal combustion engine via the intake passage, and a communication passage communicating the first gas liquid separation chamber with the second gas liquid separation chamber at one end of the internal combustion engine with respect to the cylinder row direction, the second gas liquid separation chamber including a spiral passage for causing a swirling flow of the blow-by gas in the second gas liquid separation chamber;
• a PCV valve provided in the communication passage for adjusting a flow rate of the blow-by gas;
• a one-way valve provided at another end of the internal combustion engine with respect to the cylinder row direction for expelling the blow-by gas from the second gas liquid separation chamber;
• a guide passage provided in the head cover of the internal combustion engine for communicating the breather chamber with a breather passage for conducting blow-by gas produced in the internal combustion engine, the guide passage communicating with the first gas liquid separation chamber at an end part of the first gas liquid separation chamber on the other end side of the cylinder row direction;
• a first oil return portion formed in a part of a bottom wall of the first gas liquid separation chamber on the other end side of the cylinder row direction;
• and
• a second oil return portion formed in a part of a bottom wall of the second gas liquid separation chamber on the one end side of the cylinder row direction or in a part of a bottom wall of the communication passage adjacent to the second gas liquid separation chamber,
• wherein a bottom surface of the first gas liquid separation chamber is inclined downward from one end side of the cylinder row direction to another end side of the cylinder row direction in a state where the internal combustion engine is mounted on a vehicle;
• and
• wherein a bottom surface of the second gas liquid separation chamber is inclined downward from the other end side of the cylinder row direction to the one end side of the cylinder row direction in a state where the internal combustion engine is mounted on the vehicle.

A breather system of an internal combustion engine provided with a PCV circuit for returning blow-by gas produced in the internal combustion engine fitted with a supercharger to an intake passage by using an intake negative pressure produced in the intake passage to be used for combustion once again, the breather system comprising,

• a breather chamber provided on top of a head cover of the internal combustion engine and communicating with a breather passage for conducting blow-by gas produced in the internal combustion engine, the breather chamber including a first gas liquid separation chamber extending in a cylinder row direction and communicating with the breather passage, a second gas liquid separation chamber extending in the cylinder row direction along the first gas liquid separation chamber and communicating with an interior of the internal combustion engine via the intake passage, and a communication passage communicating the first gas liquid separation chamber with the second gas liquid separation chamber at one end of the internal combustion engine with respect to the cylinder row direction, the second gas liquid separation chamber including a spiral passage for causing a swirling flow of the blow-by gas in the second gas liquid separation chamber;
• a PCV valve provided in the communication passage for adjusting a flow rate of the blow-by gas;
• a one-way valve provided at another end of the internal combustion engine with respect to the cylinder row direction for expelling the blow-by gas from the second gas liquid separation chamber;
• and
• a guide passage provided in the head cover of the internal combustion engine for communicating a breather passage for conducting blow-by gas produced in the internal combustion engine with the first gas liquid separation chamber;
• wherein the breather passage functions as an oil level gauge insertion hole, and the upper end of the breather passage communicates with the guide passage by branching off from the oil level gauge insertion hole, and the head cover includes an oil level gauge guide hole opposing a front end of the oil level gauge insertion hole and a guard member covering a part located between the oil level gauge guide hole and the oil level gauge insertion hole.