JPH11101119A - Engine crankcase emission control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine crankcase emission control system in which a shut-off valve is drawn toward the closing side by vacuum on the intake manifold side during operation of an engine, so that it is not opened until the pressure of blow-by gas in a cylinder body becomes higher than that of a conventional one, and accordingly, the consumption of lubricating oil can be minimized even though overrun occurs during stopping. SOLUTION: In an engine crankcase emission control system, a shut-off valve 1 made of a thin thick elastic material in a planar shape as viewed in a side view, is provided between a high pressure passage 3 communicated with the cylinder body side, and a low pressure passage 5 communicated with the intake manifold side, so as to be openable and closable. Further, when the outer peripheral part of the shut-off valve 1 is locked to an attaching seat 6 while a pressing surface 7 formed on one side of the center part of the shut-off valve 1 is made into contact with the high pressure passage 3, the planar shut- off valve 1 is pressed toward the other side until it is elastically deformed, as viewed in a side view, and is then attached thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas reducing device for an engine. This invention captures lubricating oil floating in a mist state when the internal pressure of the crankcase of the engine, which is an internal combustion engine, rises during operation and escapes to the intake manifold side, which is a low pressure side, to reduce escape to the outside. Is what you do.

[0002]

2. Description of the Related Art At first, a filter is provided in a breather device which is provided at the head of an engine and is open to the atmosphere to reduce the amount of lubricating oil discharged from blow-by gas. Some of them catch the lubricating oil, and some supplement them by providing a labyrinth partition in the breather path. In recent years, it has not been recognized that the blow-by gas is released to the atmosphere due to air pollution, and the blow-by gas is supplied to the intake manifold side to be used as a part of intake air.

[0003] However, in such a configuration, even if the fuel is cut off to stop the engine as a diesel engine, if the lubricating oil contained in the blow-by gas flows into the combustion chamber and burns, the engine is quickly operated. Could not stop. For this reason, the breather device had to eliminate the escape of the lubricating oil and discharge only the gas. A complicated structure for solving this problem is known from Japanese Patent Application Laid-Open No. 8-177449.

This known configuration is provided with a predicting means for predicting the oil suction amount in advance, and attempts to control the flow rate of the blow-by gas flowing through the breather pipe by the predicting means. It was expensive.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve such a problem of a conventional product, and has taken the following technical means. That is, the on-off valve 1 made of a thin elastic material having a substantially flat plate shape in a side view in a no-load state is provided between a high-pressure passage 3 communicating with the cylinder body 2 and a low-pressure passage 5 communicating with the intake manifold 4 so as to be freely opened and closed. When the outer peripheral portion of the on-off valve 1 is locked to the mounting surface seat 6 and the pressing surface 7 provided on one side of the central portion of the on-off valve 1 is brought into contact with the high-pressure path 3 in the blow-by gas reducing mechanism, Open / close valve 1
Of a blow-by gas reducing device for an engine, characterized in that the blow-by gas reduction device is mounted by pressing the other side elastically deformed in a side view.

[0006]

1 shows a blow-by gas reducing device provided on a head cover 11 of a diesel engine 10, which will be described in detail below. First of all, the engine 1
Reference numeral 0 denotes an oil pan 12 attached below the main cylinder body 2, a cylinder head 13 and a head cover 11 attached above, and a front part covered with a gear case 15,
Lower pulley 1 of crankshaft 16 in front of gear case 15
An upper pulley 19 for a water pump 7 and a water pump 18 and a cooling fan 20 are protruded. Reference numeral 21 denotes a flywheel projecting rearward of the engine 10. A box-shaped case 22 with an upper opening, to which the injection pump 14 is attached, is provided integrally with the front side of the cylinder body 2.

[0007] A lower end of the intake manifold 4 is attached to the side of the cylinder head 13, and an air cleaner 23 is mounted on a protruding upper end of the intake manifold 4.
Is attached. Reference numeral 24 denotes an intake port, from which air sucked from is removed by a filter (not shown) inside the air cleaner 23, and the intake manifold 4
After that, the air is sucked into each cylinder (not shown), and becomes air for combustion.

On the ceiling of the head cover 11, a blow-by gas reducing device mainly comprising the on-off valve 1 having a circular shape in plan view is provided. As shown in FIG. 2, the on-off valve 1 protrudes downward from the center of the circular shape at the time of no load, which is a substantially flat pressing surface 7 made of an elastic material such as rubber or soft plastic. And a cylindrical projection 8. Although the function of the projection 8 will be described later, the projection 8 may be symmetrically projected above and below the center of the circle as indicated by a virtual line.

The edge of the on-off valve 1 is placed on a mounting surface seat 6 opened to the ceiling of the head cover 11, and is attached with bolts and screws (not shown) while being clamped by a cap 9. A small hole 25 is opened in the cap 9 so that the diaphragm-like on-off valve 1 can be easily moved. The high pressure passage 3 communicating with the cylinder body 2 side is provided with combustion blow-through gas in the crankcase, the piston and the crankshaft 1.
The blow-by gas, which is pressurized by the movement of a drive rotating unit (not shown) such as a balance weight 6, acts on both. The gas pressure in the high-pressure passage 3 acts on the outer peripheral side in plan view, which is the substantially flat pressing surface 7 of the on-off valve 1. Then, the projection 8 at the center enters the inlet opening 24 of the low-pressure passage 5. That is, the high-pressure passage 3 is provided in a donut shape outside the center of the entrance opening 24 of the low-pressure passage 5.

As shown in a side view of FIG. 1, the edge 24a of the inlet opening 24 of the low pressure passage 5 is opposed to the mounting surface seat 6 of the on-off valve 1.
The portion protrudes upward and is attached so as to maintain the initial pressure in a state where the on-off valve 1 is deformed upward. The on-off valve 1 is hardly opened by blow-by gas by the mounting method that increases the elastic deformation. As described above, the on-off valve 1 is closed to be freely operated, so that the internal pressure in the crankcase is always maintained at a high level, and the inflow of blow-by gas into the low-pressure path 5 is reduced. The outlet side of the low pressure passage 5 is attached to the intake manifold 4 as shown in FIG. 4, and the blow-by gas is sent into the combustion chamber together with the outside air taken into the engine 10.

The blow-by gas acting on the high-pressure passage 3 contains mist-like lubricating oil. When the on-off valve 1 is easily opened, the gas containing mist-like lubricating oil is sent into the combustion chamber.
Even if the oil consumption increases or the fuel is cut to stop the engine, the lubricating oil contained in the blow-by gas flows into the combustion chamber and burns, so that troubles such as an inability to quickly stop the engine are likely to occur.

As in the present invention, if it is difficult to open the on-off valve 1 and the internal pressure of the crankcase is always kept high,
Since the amount of escape of the blow-by gas is reduced, the consumption of the mist lubricating oil contained in the blow-by gas is also reduced. Further, if the on-off valve 1 at the time of no load is made substantially flat and symmetrical in the vertical direction when viewed from the side, the on-off valve 1 can be inverted and used even if it is elastically deformed by long-term use, and the cost can be further reduced.

Reference numeral 26 denotes a solenoid valve, which is operated by stopping an engine stop switch 27 to thereby provide a valve 28.
Is electrically connected to the battery 29 so as to move to the closed side. By providing such a configuration, even when the closing operation of the on-off valve 1 is slowed down due to long-term use and a small amount of lubricating oil flows, blow-by gas is forcibly flown into the intake manifold 4. And the engine can be stopped reliably.

[0014]

As described above, according to the present invention, the on-off valve made of a thin elastic material having a substantially flat plate shape in a side view in a no-load state is connected to the high-pressure passage communicating with the cylinder body and the intake manifold. In a blow-by gas returning mechanism that is freely openable and closable between low-pressure paths, when the outer peripheral portion of the on-off valve is locked to the mounting surface seat and the pressing surface provided on one side of the central part of the on-off valve contacts the high-pressure path. In addition, the blow-by gas reducing device of the engine is characterized in that a substantially flat plate-like opening / closing valve is pressed and attached to the other side in a side view until the valve is elastically deformed. When acting on the pressing surface of the on-off valve to open the on-off valve and escape to the intake manifold side, the closing pressure of the on-off valve can be hardly opened, so the internal pressure of the crankcase can be constantly maintained at a high level. Since Gin rotating attract off valve by the negative pressure of the intake manifold side to the closed side,
The blow-by gas does not open until the pressure of the blow-by gas in the cylinder body becomes stronger than before, so that consumption of lubricating oil can be reduced and overrun at the time of stoppage can be reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an entire main part.

FIG. 2 is a side view of an on-off valve as a main part.

FIG. 3 is a plan view of an on-off valve as a main part.

FIG. 4 is a side view of the entire engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 On-off valve 2 Cylinder body 3 High pressure path 4 Intake manifold 5 Low pressure path 6 Mounting surface seat 7 Pressing surface

Claims (1)

[Claims] An on-off valve (1) made of a thin elastic material having a substantially flat plate shape in a side view in a no-load state between a high pressure passage (3) communicating with a cylinder body (2) and a low pressure passage (5) communicating with an intake manifold (4). In the freely provided blow-by gas returning mechanism, when the outer peripheral portion of the on-off valve 1 is locked to the mounting surface seat 6 and the pressing surface 7 provided on one side of the central portion of the on-off valve 1 is brought into contact with the high-pressure path 3 A blow-by gas reducing device for an engine, wherein an on-off valve 1 having a substantially flat plate shape is mounted by being pressed to the other side in a side view until elastically deformed.