JP3990344B2 - Blow-by gas reduction device - Google Patents

Description

  The present invention relates to a blow-by gas reduction device for circulating a blow-by gas of a multi-cylinder internal combustion engine to a combustion chamber of each cylinder.

  Blow-by gas that recirculates the blow-by gas in the crankcase to the combustion chamber of each cylinder and burns it, thereby reducing pressure pulsations in the crankcase and preventing deterioration of the lubricating oil in a closed loop without contact with the outside air Reduction (PCV) devices are known.

  In this blow-by gas reduction device, it is preferable that the flow rate of the blow-by gas to each cylinder is equal, and it is desirable that the circulation path be as short and simple as possible.

As a blow-by gas ring device based on such a viewpoint, a device in which a tournament-type branch passage is formed on a joint surface with a cylinder head in a flange that couples an intake manifold to the cylinder head is known (Patent Document 1). See).
Japanese Utility Model Publication No. 5-30412 (FIG. 3)

  However, in order not to be affected by the pressure pulsation in the crankcase, it is necessary to provide a surge tank in the recirculation passage of the blow-by gas. It has been difficult to provide a surge tank having a sufficient capacity to stably equalize the ring flow rate without increasing the size of the engine body.

  In order to eliminate such disadvantages of the prior art and to perform stable recirculation of blow-by gas to the intake system without causing an increase in the size of the engine body, a multi-cylinder internal combustion engine according to claim 1 of the present invention is provided. The blow-by gas reduction device (1) is joined with a gasket (22) sandwiched between an intake manifold (3) in which an intake passage (10) communicating with each combustion chamber is defined. A recess (indentation 6) is formed in the side wall portion of the cylinder head (2), and a first hole (round hole 25) through which blow-by gas flows into the recess is communicated with each intake passage. Two holes (small holes 24) are provided in the gasket, and blow-by gas is introduced into each intake passage through the first hole and the second hole.

  According to the second aspect of the present invention, the gas-liquid separation chamber (17) for separating oil in the blow-by gas is disposed above the intake manifold.

  According to such a configuration of the present invention, an expansion chamber having a relatively large volume can be defined without increasing the size of the engine body, so that the pressure pulsation of the crankcase can be sufficiently absorbed and a stable blow-by gas can be obtained. It is possible to achieve a great effect in realizing distributed supply to each cylinder. In addition, the gas-liquid separation chamber for separating oil in the blow-by gas can be arranged on the shortest passage from the crankcase to the intake passage, which is effective in promoting the downsizing of the blow-by gas reduction device. .

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an elevational view as seen from the flywheel side of an in-line four-cylinder internal combustion engine to which the present invention is applied. The internal combustion engine 1 is mounted on a vehicle body with the cylinder row directed in the vehicle width direction and the cylinder shaft tilted somewhat backward, and an intake manifold 3 is coupled to the front surface of the cylinder head 2 so that the cylinder head An exhaust manifold 4 is coupled to the rear surface of the two.

  As shown in FIG. 2, four intake ports 5 communicating with the combustion chambers of the respective cylinders are opened side by side on the front surface of the cylinder head 2. Above these four intake ports 4, recesses 6 of appropriate height and depth are formed continuously in the cylinder row direction. A cooling water inlet 7 and an exhaust outlet 8 of an EGR (exhaust gas recirculation) passage are opened to the right of the rightmost intake port 5.

  On the other hand, as shown in FIG. 1, the intake manifold 3 is formed by integrally connecting a curved downward portion 3a on the upstream side and a linear lateral portion 3b on the downstream side with respect to the intake flow. A flange 9 for integrally bolting the intake manifold 3 to the cylinder head 2 is integrally formed at the most downstream end of the intake.

  As shown in FIG. 3, on the joint surface of the flange 9 to the cylinder head 2, there are four intake passages 10 communicating with the intake port 5 of the cylinder head 2 and cooling formed integrally with one end of the linear lateral portion 3b. A cooling water outlet 12 connected to the water passage 11, an exhaust inlet 14 connected to the EGR chamber 13 integrally formed on the upper part of the linear lateral portion 3 b, and a blow-by gas outlet 15 connected to a gas-liquid separation chamber described later are opened. ing. In addition, an upward groove 16 that is continuous with the upper edge of the opening of each intake passage 10 is formed on the joint surface of the flange 9 to the cylinder head 2. As shown in FIG. 5, the groove 16 has a cross-sectional shape of a triangle having the deepest opening surface side.

  A gas-liquid separation chamber 17 for separating oil in the blow-by gas is disposed above the straight lateral portion 3b of the intake manifold. The side wall of the gas-liquid separation chamber 17 is connected to a blow-by gas inlet pipe 19 connected to a crankcase 18 (FIG. 1) via a PCV valve (not shown) and a straight lateral portion 3b so as to communicate with the blow-by gas outlet 15. A blow-by gas outflow pipe 21 connected to a hose joint 20 erected on the upper surface of the central portion is attached.

  A gasket 22 shown in FIG. 4 is sandwiched between the straight lateral portion 3 b of the intake manifold and the cylinder head 2. The gasket 22 has four oblong holes 23 corresponding to the intake ports 5 and the intake passages 10, and small holes (bottom holes) corresponding to the bottoms of the grooves 16 connected to the upper edges of the openings of the intake passages 10. (Second hole) 24, a round hole (first hole) 25 corresponding to the blow-by gas outflow passage 15 communicating with the hose joint 20, a hole 26 corresponding to the cooling water passage, and a hole 27 corresponding to the EGR passage. And are formed.

  The blow-by gas in the crankcase 18 that has flowed into the gas-liquid separation chamber 17 through a PCV valve (not shown) is separated from the oil in the gas-liquid separation chamber 17, and is then taken into the intake manifold from the blow-by gas outflow pipe 21 and the hose joint 20. It flows into a blow-by gas passage provided in the upper center of the straight horizontal portion 3b, and flows into a recess 6 formed in the cylinder head 2 through a blow-by gas outlet 15 and a round hole 25 of the gasket 22. And it expand | swells with the volume of the hollow 6, and flows in into each intake port 5 through the groove | channel 16 from the small hole 24 of the gasket 22. FIG.

  Thus, according to the present invention, the expansion chamber having a relatively large volume can be defined without enlarging the engine body by the recess 6 provided in the joint surface of the intake manifold 3 in the cylinder head 2. Therefore, the pressure pulsation in the crankcase 18 can be sufficiently absorbed, and stable supply of blow-by gas to each cylinder can be achieved. Further, since the gas-liquid separation chamber 17 for separating oil in the blowby gas can be disposed on the shortest path from the crankcase 18 to the intake passage 10, it is not necessary to increase the size of the blowby gas reduction device.

It is the principal part elevation seen from the flywheel side of the engine to which this invention apparatus is applied. It is an elevation view of the intake manifold mounting surface of the cylinder head. It is a rear view of an intake manifold. It is an elevation view of a gasket. It is a fragmentary sectional view which follows the VV line in FIG.

Explanation of symbols

1 Multi-cylinder internal combustion engine 2 Cylinder head 3 Intake manifold 6 Recess (recess)
10 Intake passage 17 Gas-liquid separation chamber 22 Gasket 24 Small hole (second hole)
25 round holes (first hole)

Claims (2)

A blow-by gas reduction device for circulating the blow-by gas of a multi-cylinder internal combustion engine to the combustion chamber of each cylinder,
Forming a recess in a side wall portion of a cylinder head to which a gasket sandwiched between an intake manifold having an intake passage communicating with each combustion chamber is formed;
The gasket is provided with a first hole for allowing blow-by gas to flow into the recess and a second hole for allowing the recess to communicate with each intake passage.
A blow-by gas reducing apparatus, wherein blow-by gas is introduced into each intake passage through the first hole and the second hole.   The blow-by gas reduction device according to claim 1, wherein a gas-liquid separation chamber for separating oil in the blow-by gas is disposed above the intake manifold.

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