JPS5893913A - Reducing device of blow-bye gas - Google Patents

Abstract

PURPOSE:To hold pressure or the like in an engine space part to a fixed level without causing the necessity for using a particular control valve, by arranging an opening end, which appears in an intake manifold of a reducing route of blow-bye gas, in the reverse direction to an intake air flow. CONSTITUTION:At high speed operation of an engine 1, negative pressure in an intake manifold 8, that is, static pressure increases to a minus direction, on the contrary, dynamic pressure generated by a flow of blow-bye gas increases to a plus direction. Accordingly, resultant pressure (dynamic pressure+static pressure) in an opening end 9a arranged toward the reverse direction to an intake flow in a reducing route 9 of blow-bye gas is controlled to an almost fixed level in no relation to an engine speed. In this way, pressure and flow of blow-bye gas in an engine space part 5 in a pipe P, crank case and cylinder head cover constituting the route 9 can be always held to a fixed level.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blow-by gas reduction device for an engine.
This invention relates to a blow-by gas reduction device that maintains the pressure within an engine space constant by utilizing the balance between dynamic pressure and static pressure due to the flow of intake air in an intake manifold.

Conventionally, when an explosion occurs in the combustion chamber of an engine, the combustion gas becomes blow-by gas, which intrudes from the combustion chamber of the cylinder into the space inside the engine, such as the crankcase and cylinder, and into the space inside the rad cover. The internal pressure could become excessive.

To prevent this, conventionally, the space was made with ventilation holes, but the blow-by gas contains oil mist such as gasoline, diesel oil, and engine oil, as well as 802NO2 and unburned hydrocarbons. There was a problem of air pollution. Therefore, closed-type blowby gas reduction devices have been used that return this blowby gas to the engine's intake manifold and re-burn it. However, with this device, the large negative pressure generated in the intake manifold acts on the engine space. Therefore, the disadvantage of 6D is that it is difficult for dust to enter from the outside of the engine, and oil deterioration is accelerated.
In order to eliminate this drawback, it is necessary to keep the pressure in the engine space constant, but the conventional closed type material called PCV pulp used for this purpose has a complicated structure and is expensive. The present invention was made to eliminate the above-mentioned drawbacks of the prior art, and its objective is to connect the open end of the blow-by gas reduction path to the intake air in the intake manifold. By arranging it in the opposite direction to the flow, it takes advantage of the balance between static pressure and dynamic pressure generated by the intake flow, and can be used in engine spaces such as the inside of the crankcase without using a special control valve. It is possible to maintain the pressure of the engine and the flow rate of the blow-by gas at a certain level.This also prevents dust from entering the engine space from outside the engine, prevents oil deterioration, and also prevents the blow-by gas from entering the engine space. This is to prevent air pollution by not releasing gas directly into the atmosphere.

In short, the present invention is characterized in that the open end of the blow-by gas return path, which is connected to the space inside the engine, is oriented in the opposite direction to the flow of intake air in the intake manifold, and is connected to the intake manifold. That is.

The present invention will be explained below based on embodiments shown in the drawings. 1st
In the figures and FIG. 2, an engine 1 is equipped with a blow-by gas reducing device 2.
consists of a pipe P that constitutes a blow-by gas return path 9 that extends from a space 5 in the engine 1, that is, a space in the crankcase 6, and a space in the cylinder head cover to the intake manifold 8. In addition, 3 is a cylinder, 44-i combustion chamber, 11 is a piston, 12 is a connecting rod, 1
3I"i crankshaft, 14tj oil pan, 1
5 is the cylinder head, 16 is the exhaust manifold 0 In FIGS. 2 and 3, the blow-by gas return path 9
The opening end 9a of the pipe P is arranged to face the direction opposite to the flow of intake air in the intake manifold 8, and the pipe P is connected to the intake manifold 8.
is connected to. Although not shown in the drawings, a separation device such as a labyrinth is provided at the connection portion of the pipe P to the cylinder and the rad cover 7. The open end 9a is constituted by an elbow-shaped bent pipe 17, and its flange portion 17a
It is fixed to the intake manifold 8 together with a pipe fitting 19 via an i'l' canucket 18. One end Pa of the pipe P is attached to a fitting 2 fixed to the cylinder head cover 7.
0, and the other end Pb is inserted into and fixed to a fitting 19 of the intake manifold 8.

The present invention is constructed as described above, and its operation will be explained below. 3 and 4, as the rotational speed of the engine 1 increases, the negative pressure, A'lJ, static pressure in the intake manifold 8 increases in the negative direction, as shown by the dashed line in FIG. However, on the other hand, the dynamic pressure generated by the flow of blow-by gas increases in the positive direction, as shown by the broken line. Therefore, blow-by gas reduction route 9
As shown by the solid line, the combined pressure (dynamic pressure and static pressure) at the open end 9a of the engine is approximately constant regardless of the engine speed. As a result, the pipe P and the engine space 5
The pressure in the engine space and the flow rate of the blowby gas are always kept constant, and only when the pressure of the blowby gas rises above a certain value, a large amount of blowby gas flows into the intake manifold 8 and is reburned. Excessive negative pressure inside the engine space 5 does not occur, dust does not enter the engine space 5 from the oil seal of the crankshaft 13, and deterioration of the oil can be prevented. In addition, there is no need for a special control valve1, the configuration is extremely simple, and there is no need to worry about breakdowns◇Since the present invention is configured and functions as described above, it is possible to open the blow-by gas reduction path. By arranging the end of the intake manifold in the opposite direction to the flow of intake air, the static pressure (
It is possible to utilize the balance between negative pressure) and dynamic pressure (positive pressure),
This has the effect that the pressure in the engine space such as the crankcase and the flow rate of the blow-by gas can be kept constant without using a special control valve. As a result, it is possible to prevent dust from entering the internal space of the engine from the outside of the engine, and to prevent oil deterioration and air pollution due to the extremely one-piece structure.This invention has an extremely large practical effect. be.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention; FIG. 1 is a plan view of an engine equipped with a blow-by gas reduction device; FIG. 2 is a schematic front view of the engine shown in FIG. 1; and FIG. FIG. 4 is an enlarged cross-sectional view of the second south section taken along arrows ■-m showing the reduction and the back position, and FIG. 4 is a diagram showing the pressure state at the open end in the intake manifold of the blow-by gas return path. 1 is an engine, 2 is a blow-by gas return device, 8 is an intake manifold, 9 is a blow-by gas return path, and 9a is an open end. Patent Applicant Hino Motors Co., Ltd. Agent Patent Attorney 1) Japanese 7- Figure 1 Figure 2 m = ←

Claims (1)

[Claims] Blowby gas reduction characterized in that the open end of the blowby gas return path, which is connected to a space inside the engine, is oriented in the opposite direction to the flow of intake air in the intake manifold, and is connected to the intake manifold. Device.