JPH04237811A - Blowby gas reduction device of engine - Google Patents

Abstract

PURPOSE:To inhibit the excessive intake of a blowby gas even when a crank chamber is biased in negative pressure, so as to prevent the overrunning of engine. CONSTITUTION:When the increase in the negative pressure of a crank chamber 5 is detected by putting a pressure detector 6 on the crank chamber 5, providing a flow adjusting valve 7 on a blowby gas reduction route 2, and by having the pressure detector 6 interlocked with the flow adjusting valve 7 through a valve driving device 8, the flow adjusting valve 7 is closed by the valve driving device 8 in the direction A where the passage cross sectional area of the blowby gas reduction route 2 is reduced. Since the negative pressure of the crank chamber 5 is not easily transmitted to the side of the blowby gas reduction route 2, the overrunning of an engine is prevented.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a device for returning engine blow-by gas to the intake passage, and is capable of preventing engine overrun by eliminating excessive intake of blow-by gas even when the crank chamber is tilted to negative pressure. provide something.

0002

2. Description of the Related Art Generally, blow-by gas blown from the combustion chamber of an engine into the crank chamber is drained of oil by a breather device, and then only the gas is returned to the intake passage. The subject of the present invention is this closed type breather device, and its basic structure is as shown in FIG. 1 or 4.
The outlet 3 of the breather device 1 is connected to the intake path 4 of the engine E via the blow-by gas return path 2, and the crank chamber 5 of the engine E is connected to the intake path through the breather device 1 and the blow-by gas return path 2. This is a form that communicates with 4.

In this type of prior art, as shown in FIG. 4, a breather device 1 is arranged in a rocker arm chamber of a vertical overhead valve engine E, and a blow-by gas return path 2 consisting of a vent pipe is connected to an intake pipe 4. There is something I did.

0004

[Problems to be Solved by the Invention] In the above-mentioned prior art, when the crank chamber 5 tilts significantly toward negative pressure during operation of the engine E, the blow-by gas return path 2 is connected to the intake pipe 4 communicating with the crank chamber 5 during the intake stroke. As the amount of blow-by gas sucked in through the combustion chamber increases, excess fuel is supplied to the combustion chamber.
There is a risk that engine E will overrun. The present invention
The technical challenge is to prevent the engine from overrunning even if the crank chamber is tilted to negative pressure.

[0005]

[Means for Solving the Problems] Means for achieving the above objects will be explained below with reference to drawings showing embodiments. That is, the present invention provides a blow-by gas reduction device for an engine having the basic structure described above, in which a pressure detector 6 is provided in the crank chamber 5, a flow rate adjustment valve 7 is provided in the blow-by gas return path 2, and
The pressure detector 6 is linked to the flow rate adjustment valve 7 via the valve drive device 8, and when the negative pressure in the crank chamber 5 increases, the flow rate adjustment valve 7 decreases the passage cross-sectional area of the blow-by gas return path 2 in the direction A. The present invention is characterized in that when the valve is closed and the negative pressure in the crank chamber 5 becomes smaller, the flow rate adjustment valve 7 is opened in a direction B that increases the passage cross-sectional area of the blow-by gas return path 2. It is.

The valve drive device 8 is, for example, an electric drive device that is a combination of a solenoid and a control circuit, or a diaphragm drive device that operates directly in response to changes in atmospheric pressure. In addition, in the case of a diaphragm type, the pressure detector 6 can also be integrated into the valve drive device 8.

[0007]

[Operation] When the negative pressure in the crank chamber 5 increases, the valve drive device 8 detects the increase in negative pressure from the pressure detected by the pressure detector 6 and closes the flow rate regulating valve 7, thereby opening the blow-by gas return path 2. It is displaced in the direction A that reduces the cross-sectional area of the passage, thereby making it difficult for the negative pressure of the crank chamber 5 to affect the ventilation upper side of the flow rate regulating valve 7 of the blow-by gas return passage 2. Therefore, an increase in the amount of blowby gas sucked from the blowby gas return path 2 into the intake path 4 is suppressed.

On the other hand, when the negative pressure in the crank chamber 5 becomes smaller, the flow rate adjustment valve 7 opens in the direction B that increases the passage cross-sectional area of the blow-by gas return path A, and the flow rate adjustment valve 7 opens on the ventilation upper side of the flow rate adjustment valve 7. Negative pressure in the crank chamber 5 can be applied smoothly. Therefore, from the blow-by gas return path 2 to the intake path 4
Blow-by gas is sucked in well.

[0009]

Effects of the Invention: (1) When the negative pressure in the crank chamber increases, the flow rate adjustment valve closes the blow-by gas return path, suppressing the increase in the amount of blow-by gas sucked into the intake path. overrun can be smoothly prevented. Conversely, when the negative pressure in the crank chamber becomes smaller, the flow rate adjustment valve opens the blow-by gas return path, and the blow-by gas is sucked into the intake path, so that the performance of the breather device can be maintained well.

(2) A pressure detector is installed in the crank chamber, and
Since a flow rate regulating valve is provided in each blow-by gas return path and the two are configured to be able to be controlled in conjunction with each other, there is no need for a large-scale dedicated device, and the process can be implemented at low cost.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 is a longitudinal cross-sectional view of a vertical overhead valve engine, and FIG. 2 is a longitudinal cross-sectional view of a main part of a blow-by gas return path.

A cylinder head 14 and a head cover 15 are assembled in order above the cylinder 13 of the vertical engine E, and a breather device 1 is attached to the upper part of the head cover 15. The crank chamber 5 of the engine E is communicated with a tappet chamber 16 of the cylinder 13 through an air passage 17, and the tappet chamber 16 is communicated with a rocker arm chamber 19 in the head cover 15 through a push rod insertion hole 18.

The breather device 1 is filled with an oil cutting member 21 such as glass wool, and the breather chamber 2 above it is filled with an oil cutting member 21 such as glass wool.
0, the breather inlet (not shown) of the breather device 1 faces the rocker arm chamber 19, and the outlet 3 of the breather chamber 20 communicates with the intake pipe 4 of the engine E via the blow-by gas return path 2.

As shown in FIG. 2, a flow rate regulating valve 7 is provided in the middle of the blow-by gas return passage 2 so as to be movable forward and backward with respect to the passage of the intake pipe 4. The solenoid type electromagnet 10 is fixed to a location near the
Connect to 3. Further, as shown in FIG. 1, a barometric pressure detector 6 is attached to the crank chamber 5 of the engine E, and the barometric pressure detector 6 is connectably connected to the electromagnet 10 via a control means 11.

In this case, the solenoid type electromagnet 10 and the control means 11 constitute a valve driving means 8 for the flow rate regulating valve 7, and as shown in FIG. 2, when the negative pressure in the crank chamber 5 increases, the flow rate regulating valve 7 When the valve closes in the advancing direction A which reduces the passage cross-sectional area of the blow-by gas return passage 2, and the negative pressure in the crank chamber 5 becomes smaller, the flow rate regulating valve 7 moves out to increase the passage cross-sectional area of the blow-by gas return passage 2. The valve is configured to open in direction B.

The functions of this embodiment will be explained with reference to FIG. (1) When the negative pressure in the crank chamber 5 increases, the control means 11 calculates the increase in negative pressure based on the detection signal from the pressure detector 6.
outputs a valve closing operation signal to the solenoid electromagnet 10. The flow rate regulating valve 7 operated by the electromagnet 10 closes in the advance direction A, and the passage cross-sectional area A of the blow-by gas return path 2 decreases, so that the flow rate regulating valve 7 of the blow-by gas return path 2 is ventilated. The side is less affected by the negative pressure in the crank chamber 5. Therefore, an increase in the amount of blowby gas sucked into the intake path 4 from the blowby gas return path 2 is suppressed, and overrun of the engine can be smoothly prevented.

(2) When the negative pressure in the crank chamber 5 becomes smaller, the control means 11 which calculates the decrease in negative pressure based on the detection signal from the pressure detector 6 outputs a valve opening operation signal to the solenoid type electromagnet 10. The flow rate regulating valve 7 operated by the electromagnet 10 is opened in the exit direction B, and the blow-by gas return path 2 is opened.
Since the cross-sectional area of the passage increases, the negative pressure in the crank chamber 5 is smoothly applied to the ventilation upper side of the flow rate regulating valve 7. Therefore, the blowby gas is well sucked from the blowby gas return path 2 into the intake path 4, and the breather performance inherent to the breather device can be maintained well.

FIG. 3 shows a modification of the interlocking mechanism between the flow rate adjustment valve 7 and the electromagnet 10, in which a rotating electromagnet 10a such as a clapper type or solenoid clapper type is used as the electromagnet, and the flow rate adjustment valve The cross-sectional area of the blow-by gas return path 2 is increased or decreased by the rotational drive of the blow-by gas return path 2.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a vertical overhead valve engine.

FIG. 2 is a longitudinal sectional view of a main part of a blow-by gas return path of the engine.

FIG. 3 is a modification of an interlocking mechanism between a flow rate regulating valve and an electromagnet.

FIG. 4 is a diagram corresponding to FIG. 1 showing the prior art;

[Explanation of symbols]

E engine 1 Breather device 2 Blow-by gas return path 3 Exit 1 4 Intake path 5 Crank chamber 6 Pressure detector 7 Flow rate adjustment valve 8 Valve drive device 10 Solenoid type electromagnet 11 Control means A　　2 passage cross-sectional area decrease direction B. Increasing direction of passage cross-sectional area of 2

Claims (1)

[Claims] [Claim 1] A breather device (1) on the engine (E).
The outlet (3) of the breather device (1) is connected to the intake path (4) of the engine (E) via the blow-by gas return path (2).
) and communicates the crank chamber (5) of the engine (E) with the intake passage (4) via the breather device (1) and the blow-by gas return passage (2). A pressure detector (6) is installed in the chamber (5).
), a flow rate adjustment valve (7) is provided in the blow-by gas return path (2), a pressure detector (6) is linked to the flow rate adjustment valve (7) via a valve drive device (8), and this valve Drive device (8
), when the negative pressure in the crank chamber (5) increases, the flow rate regulating valve (7) closes in the direction (A) that reduces the passage cross-sectional area of the blow-by gas return path (2), and the
When the negative pressure becomes smaller, the flow rate adjustment valve (7) increases the passage cross-sectional area of the blow-by gas return path (2) (B).
A blow-by gas reduction device for an engine, characterized in that it is configured to open a valve when the valve is opened.