JP2003278522A - Blow-by gas reflex device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow-by gas reflux device for an internal combustion engine, which certainly prevents the entry of an oil ingredient and the like included in blow-by gas, and reduces the accumulation of the deposit in a intake system. <P>SOLUTION: When the actuation of an internal combustion engine is detected, a liquid returning passage is forcibly intercepted by an opening/closing means to store liquid ingredients in the blow-by gas in a gas-liquid separator (S10, S12). When a stop state of the internal combustion engine is detected, the liquid returning passage is forcibly communicated by the opening/closing means to return the liquid ingredients stored in the gas-liquid separator to a liquid reservoir through the liquid returning passage (S10, S14). <P>COPYRIGHT: (C)2004,JPO

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 recirculation system for an internal combustion engine, and more particularly to preventing deposits made of oil components contained in blow-by gas from adhering to intake valves and intake port walls. Regarding technology.

[0002]

2. Related Background Art In an internal combustion engine (engine), a part of exhaust gas burned in a combustion chamber leaks to the crankcase side as blow-by gas from a gap between a cylinder wall and a piston, and the blow-by gas is taken into the intake system. The technology of recirculating the gas into the combustion chamber and recombusting it in the combustion chamber has been put into practical use.

However, a lot of oil mist of lubricating oil is scattered in the crankcase into which the blow-by gas flows, and when the blow-by gas is returned to the intake system of the engine by containing such lubricating oil, intake air is taken. There is a problem that the oil component adheres to the wall surfaces of the valve and the intake port and accumulates as a deposit, which adversely affects the operation of the intake valve and the intake efficiency.

From the above, for example, it is considered that a barrier is provided in the camshaft case and the blow-by gas is guided into the camshaft case and collided with the barrier to drop and recover the liquid component in the blow-by gas. However, in this method, the liquid component in the blow-by gas cannot be sufficiently recovered because the size of the camshaft case is limited.

Therefore, in order to prevent the oil component, which is the main component of the deposit, from entering the intake system, a dedicated gas-liquid separator is provided in the upstream portion of the blow-by gas passage, and only the gas component is sucked by the negative pressure in the intake system. While being sent to the system, the oil component is captured, dripted and stored in the gas-liquid separator.

[0006]

By the way, when the oil component is stored in the gas-liquid separator, there is a problem that the stored oil must be discharged. For example, the gas-liquid separator is provided with a drain hole. It is considered to return the oil component from the drain hole into the oil passage or the crankcase.

However, while the engine is operating, the pressure in the intake system is negative, while the pressure in the oil passage and the crankcase is atmospheric pressure or positive pressure, so that the gas is stored in the gas-liquid separator. There is a problem in that much of the oil component that has been caused is sucked back into the intake system due to the pressure difference without being returned. And this tendency becomes more remarkable as the engine speed increases.

Therefore, a device provided with a poppet valve at the bottom of the gas-liquid separator, which is closed by the negative pressure of the intake pipe during the operation of the engine, and is opened by the weight of the oil when the engine is stopped. Is disclosed, for example, in Japanese Patent Laid-Open No. 2000-8828. However, in the case of the poppet valve disclosed in the above publication, the valve may not be sufficiently closed when the negative pressure of the intake pipe is close to the atmospheric pressure even when the engine is operating, and even when the engine is stopped, When the poppet valve is stuck due to an increase in viscosity due to deterioration of oil over time, the valve may not be sufficiently opened if the amount of oil stored is small, and it cannot be said that the valve is highly reliable.

The present invention has been made to solve such a problem, and an object of the present invention is to reliably prevent an oil component or the like contained in blow-by gas from entering the intake system, and It is an object of the present invention to provide a blow-by gas recirculation device for an internal combustion engine capable of reducing deposit accumulation in the system.

[0010]

In order to achieve the above-mentioned object, according to the invention of claim 1, a recirculation passage for recirculating blow-by gas to an intake system, and a recirculation passage interposed between the recirculation passage and the blow-by gas. A gas-liquid separator that separates and stores a liquid component, a liquid return passage that is connected to the gas-liquid separator and returns the stored liquid component to a liquid reservoir, and the gas-liquid separator and the liquid return passage When the operation of the internal combustion engine is detected by the opening / closing means interposed between the liquid return passage and the operating state detecting means for detecting the operating state of the internal combustion engine, and the operating state detecting means for detecting the operation of the internal combustion engine. And a control means for blocking the liquid return passage by the opening / closing means and for communicating the liquid return passage when a stop state of the internal combustion engine is detected.

That is, when the operation of the internal combustion engine is detected by the operation state detecting means, the liquid return passage is blocked by the opening / closing means and the liquid component in the blow-by gas is well stored in the gas-liquid separator. When the stop state of the internal combustion engine is detected, the liquid return passage is connected by the opening / closing means and the liquid component stored in the gas-liquid separator is returned to the liquid reservoir via the liquid return passage.

Therefore, when the liquid return passage is communicated during the operation of the internal combustion engine, the inside of the intake system is at a negative pressure, while the liquid reservoir is at atmospheric pressure or positive pressure, so that the liquid is stored in the gas-liquid separator. The liquid component may be sucked into the intake system due to the pressure difference, but the liquid return passage is blocked by the opening / closing means during the operation of the internal combustion engine. Is reliably prevented, and when the internal combustion engine is in a stopped state, the inside of the intake system is returned to atmospheric pressure, so the liquid return passage is connected by the opening / closing means, and The liquid component stored in is reliably returned to the liquid reservoir via the liquid return passage without being sucked into the intake system. As a result, the accumulation of deposits on the intake valve and the intake port wall is reliably reduced, and malfunction of the intake valve and a decrease in intake efficiency are suppressed.

Further, in the invention of claim 2, the opening / closing means includes a solenoid valve which is closed by energization while being normally opened when not energized, and the control means is controlled by the operating state detecting means by the internal combustion engine. It is characterized in that the solenoid valve is closed by energizing only when the operating state of the engine is detected to close the liquid return passage. In other words, during operation of the internal combustion engine, the solenoid valve is closed by energization and the liquid return passage is blocked, and the liquid component in the blow-by gas is well stored in the gas-liquid separator and enters the intake system. On the other hand, when the stop state of the internal combustion engine is detected, the solenoid valve is automatically opened by disconnecting the solenoid valve and the liquid return passage is made to communicate with each other. The liquid component stored in the separator is reliably returned to the liquid reservoir via the liquid return passage.

Therefore, when the internal combustion engine is stopped, the power is normally turned off. However, even when the power is turned off in this way, the liquid return passage can be surely communicated with each other, thus saving power. The accumulation of deposits on the intake valve and the intake port wall is reliably reduced while increasing the efficiency. Also,
According to a third aspect of the present invention, a storage amount detecting means for detecting the storage amount of the liquid component stored in the gas-liquid separator and a warning means are further provided, and the warning means is detected by the storage amount detecting means. A warning is issued when the stored amount of the liquid component that exceeds the predetermined amount exceeds a predetermined amount.

Therefore, for example, when the operation is continued for a long time and the stored amount of the liquid component exceeds the predetermined amount, a warning is issued to prompt the driver to stop the internal combustion engine, Excessive storage and overflow of the liquid component stored in the gas-liquid separator are prevented in advance.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the first embodiment will be described. Referring to FIG. 1, there is shown a schematic configuration diagram of a blow-by gas recirculation apparatus for an internal combustion engine mounted on a vehicle according to the present invention. Hereinafter, the configuration of the blow-by gas recirculation apparatus will be described.

As shown in FIG. 1, an internal combustion engine (hereinafter, simply referred to as an engine) 1 has a fuel injection mode that is switched between fuel injection in an intake stroke (intake stroke injection) and a fuel injection in a compression stroke (compression). A cylinder injection type spark ignition type gasoline engine capable of performing stroke injection is adopted.
This in-cylinder injection type engine 1 can be easily operated at a stoichiometric air-fuel ratio (Stoichio) or at a rich air-fuel ratio (rich air-fuel ratio operation), or at a lean air-fuel ratio (lean air-fuel ratio operation). Is feasible.

As shown in FIG. 1, an engine 1 is constructed by mounting a cylinder head 2 on a cylinder block 3, forming a plurality of cylinders 3a on the cylinder block 3, and inserting a piston 4 into each cylinder 3a. Has been done. The piston 4 is connected to a crankshaft (not shown) via a connecting rod 5, and a combustion chamber 6 is formed between the upper surface of each piston 4 and the cylinder head 2. The connecting rod 5 and the crankshaft are housed in a crankcase 3b integrally formed in the lower part of the cylinder block 3, and an oil pan 3c for storing lubricating oil is attached to the bottom of the crankcase 3b. .

An electromagnetic fuel injection valve 10 is attached to the cylinder head 2 for each cylinder together with an ignition plug 8 so that fuel can be directly injected into the combustion chamber. Ignition coil 9 that outputs a high voltage to spark plug 8
Is connected, and the fuel pipe 1 is connected to the fuel injection valve 10.
A fuel supply device (not shown) having a fuel tank is connected via 1. More specifically, the fuel supply device is provided with a low-pressure fuel pump and a high-pressure fuel pump, whereby the fuel in the fuel tank is supplied with fuel.
In contrast, the fuel can be supplied at a low fuel pressure or a high fuel pressure, and the fuel can be injected from the fuel injection valve 10 toward the combustion chamber at a desired fuel pressure.

In addition, the cylinder head 2 is formed with an intake port 13 in a substantially upright direction for each cylinder, and the intake manifold 12 communicates with each intake port 13.
One end of each is connected. The intake manifold 12 is provided with an electromagnetic throttle valve 14 that adjusts the intake air amount. An exhaust port 17 is formed in the cylinder head 2 in a substantially horizontal direction for each cylinder, and one end of an exhaust manifold 16 is connected so as to communicate with each exhaust port 17.

Further, the cylinder head 2 has an intake valve 20 for connecting and disconnecting the intake port 13 and the combustion chamber 6.
An exhaust valve 22 for connecting and disconnecting the exhaust port 17 and the combustion chamber 6 is provided, and various valve operating mechanisms (camshaft, rocker arm, etc.) for operating the intake valve 20 and the exhaust valve 22 are provided. There is. Then, on the upper part of the cylinder head 2, a rocker cover 24 is mounted on the intake valve 20 side and a rocker cover 26 is mounted on the exhaust valve 22 side in an airtight state via a gasket or the like so as to cover various valve operating mechanisms. As a result, a PCV (Positive Crankcase Ventilation) chamber 30 is formed between the cylinder head 2 and the rocker cover 24, and a breather chamber 32 is formed between the cylinder head 2 and the rocker cover 26.

As shown in the figure, a breather pipe 34 extends from the breather chamber 32.
Is connected to the intake pipe on the upstream side of the throttle valve 14. A communication passage 36 is bored in the cylinder block 3 so as to communicate the breather chamber 32 and the inside of the crankcase 3b.
A communication passage 38 is formed so as to communicate the inside with the PCV chamber 30. And PCV is on the rocker cover 24
A valve 40 is attached, and a PCV pipe (reflux passage) 42 extends from the PCV valve 40,
The tip of the pipe 42 is connected to the intake manifold 12. The PCV valve 40 functions as a flow rate adjusting valve capable of adjusting the flow rate according to the atmospheric pressure.

As a result, when the fuel burns in the combustion chamber 6 and the piston 4 reciprocates in the cylinder 3a, a part of the exhaust gas flows out into the crankcase 3b as a blow-by gas from the gap between the cylinder 3a and the piston 4. However, when the intake manifold 12 has a negative pressure due to the operation of the piston 4, the negative pressure causes the blow-by gas to be scavenged by the air introduced from the breather pipe 34 through the breather chamber 32 and the communication passage 36, while the communication passage 38, PCV room 3
0 and the PCV pipe 42 and is supplied into the intake manifold 12 (solid arrow). Then, the blow-by gas is reburned together with fresh air in the combustion chamber 6.
At this time, the flow-back amount of blow-by gas is PCV depending on the negative pressure.
Adjusted by valve 40.

By the way, the lubricating oil stored in the oil pan 3c passes through oil passages formed in the cylinder head 2 and the cylinder block 3 to operate various valve operating mechanisms, pistons 4, connecting rods 5, crankshafts and the like. Since the crankshaft rotates at a high speed in the crankcase 3b, the lubricating oil is scattered and becomes an oil mist, and is blown into the blow-by gas. A large amount of the oil mist is contained.

Therefore, the PCV pipe 42 has an oil separator (gas-liquid separator) for separating the oil component (liquid component) contained in the blow-by gas and the exhaust gas component.
44 is interposed. As shown in the figure, the oil separator 44 has, for example, a partition wall 45 in the central portion and an oil reservoir 46, and when blow-by gas flowing from the PCV valve 40 collides with the partition wall 45, the oil component drops. The oil is stored in the oil reservoir 46, and only the gas component is recirculated to the intake system.

The oil separator 44 is not limited to the one shown in FIG. 1, but may be of a construction such that the blow-by gas that has flowed in is not discharged straight as it is, as shown in variations in FIGS. 2 (a) to 2 (d). It may be of any type, and may not have the partition wall 45 as shown in FIGS. 2B to 2D. A liquid amount sensor (reserved amount detecting means) 47 is attached to a predetermined position of the oil separator 44.

A return pipe (liquid return passage) 48 extends from the oil reservoir portion 46 of the oil separator 44 through an electromagnetic on-off valve (opening / closing means) 50, and its tip is connected to the oil passage or the crankcase 3b. Has been done. That is,
When the electromagnetic on-off valve 50 is opened, the oil component accumulated in the oil reservoir 46 is returned to the oil passage or the crankcase 3b, that is, the oil pan 3c via the return pipe 48 (broken line arrow).

As shown in FIG. 3, the electromagnetic on-off valve 50 is a normally open type which is closed when energized, but is kept open by the biasing force of the spring 52 when not energized. (Normally open) solenoid valve is used. Therefore, when the opening / closing valve 50 is closed by energization, the return pipe 48 is shut off and the oil component separated from the blow-by gas is stored in the oil reservoir 46, and when the energization is released, the opening / closing valve 50 is automatically opened. The oil component stored in the oil reservoir 46 by opening the valve is returned to the oil pan 3c through the return pipe 48.

The ECU 60 includes an input / output device and a storage device (R
OM, RAM, non-volatile RAM, etc., central processing unit (C
PU), a timer counter, etc.
By 0, comprehensive control of the blow-by gas recirculation device including the engine 1 is performed. On the input side of the ECU 60,
Various sensors such as a liquid amount sensor 47 and a crank angle sensor 62 for detecting a crank angle are connected, and detection information from these sensors is input. Based on the crank angle information of the crank angle sensor 62, the engine speed N
e is required.

On the other hand, on the output side of the ECU 60, various output devices such as the ignition coil 9, the fuel injection valve 10, the throttle valve 14, the opening / closing valve 50, and a warning lamp (warning means) 64 are connected. Commands for fuel injection amount, fuel injection timing, ignition timing, throttle opening, etc., which are calculated based on detection information from various sensors, are output to these various output devices.

Hereinafter, the operation of the blow-by gas recirculation device according to the present invention having such a structure, that is, the electromagnetic on-off valve 5 will be described.
The open / close control of 0 will be described. Referring to FIG. 4, a control routine of solenoid valve control according to the present invention is shown in a flow chart, which will be described below with reference to FIG. In step S10, it is determined whether the operating state of the engine 1 is in the stopped state (operating state detecting means). Here, for example, the engine rotation speed Ne calculated based on the information from the crank angle sensor 62 is a predetermined rotation speed (for example, 100 r
It is less than pm). So here,
By determining whether or not the engine 1 is in a stopped state, the oil component stored in the oil reservoir 46 of the oil separator 44 causes the intake manifold 12 when the opening / closing valve 50 is opened.
It is determined whether the pressure in the intake manifold 12 is so close to the atmospheric pressure that it is not sucked into the intake system due to the negative pressure inside.
It should be noted that the stopped state of the engine 1 may be determined by whether or not the ignition key is off, or the pressure in the intake manifold 12 may be directly detected so that the pressure in the intake manifold 12 is predetermined. Negative pressure (eg,
The determination may be made based on whether the atmospheric pressure is more than −10 mmHg). Further, the solenoid valve (open / close valve 50) may be automatically turned on / off in synchronization with the on / off operation of the ignition key performed by the driver without determining whether the engine is stopped.

If the determination result of step S10 is false (No),
That is, the engine speed Ne is equal to or higher than the predetermined speed,
The intake manifold 12 while the engine 1 is in normal operation
If it is determined that the inside pressure is sufficiently negative, step S
12, the on-off valve 50 is energized (turned on) to be closed. As a result, the return pipe 48 is shut off and the oil component separated from the blow-by gas is stored in the oil reservoir 46 (control means).

In this case, since the on-off valve 50 is forcibly closed reliably by energization, the oil component stored in the oil reservoir 46 during normal operation of the engine 1 is sucked by the negative pressure in the intake manifold 12. The suction to the system is surely prevented. On the other hand, when the determination result of step S10 is true (Yes), that is, when the engine rotation speed Ne is less than the predetermined rotation speed, the engine 1 is stopped, and the inside of the intake manifold 12 is determined to be close to the atmospheric pressure, Then, the process proceeds to step S14, and the energization of the on-off valve 50 is released (turned off). Alternatively, when the ignition key is turned off, the power supply is automatically released. As a result, the opening / closing valve 50 is opened by the urging force of the spring 52, the return pipe 48 communicates, and the oil component stored in the oil reservoir 46 is returned to the oil pan 3c through the return pipe 48 (control means). .

In this case, since the opening / closing valve 50 is forcibly and surely opened by the urging force of the spring 52, the oil sump is retained when the engine 1 is in a stopped state where the pressure in the intake manifold 12 is close to the atmospheric pressure. The oil component stored in the portion 46 is reliably returned to the oil pan 3c without being sucked into the intake system. As a result, when the oil component adheres to the wall of the intake port 13 or the intake valve 20, it reacts with the exhaust gas component and becomes a deposit, which accumulates on the wall of the intake port 13 or the intake valve 20.
Accumulation of such deposits is reliably reduced, and malfunction of the intake valve 20 and reduction in intake efficiency are suppressed.

In particular, since the normally open solenoid valve is used here as the opening / closing valve 50, it is not necessary to energize the engine 1 when the engine 1 is in a stopped state, so that the battery is prevented from running out and power is saved. However, the accumulation of deposits on the intake valve 20 and the intake port 13 wall can be reliably reduced. In step S12, when the open / close valve 50 is energized and closed, the amount of the oil component stored in the oil reservoir 46, that is, the oil amount exceeds a predetermined amount based on the information from the liquid amount sensor 47. It is determined whether or not. When the determination result is true (Yes) and it is determined that the oil amount exceeds the predetermined amount, the process proceeds to step S18, and the warning lamp 64 is turned on. That is, when the operation is continued for a long time, a large amount of oil component is accumulated in the oil separator 44, but when the oil amount exceeds a predetermined amount, the driver is notified of that fact and the engine 1 is stopped. Urge you to. This prevents the oil component stored in the oil separator 44 from being excessively stored or overflowed.

On the other hand, when the determination result is false (No) and the oil amount is less than the predetermined amount, the warning lamp 64 is turned off. Next, a second embodiment will be described. Figure 5
Referring to FIG. 2, there is shown a part of a schematic configuration diagram of a blow-by gas recirculation system for an internal combustion engine according to a second example of the present invention. Hereinafter, based on the figure, the blow-by gas recirculation system according to the second example is shown. The configuration of will be described. It should be noted that here, only parts different from the first embodiment will be described.

As shown in FIG. 5, in the second embodiment, a negative pressure tank 70 is connected to the intake manifold 12 via an electromagnetic on-off valve 50 '. When the internal pressure of the negative pressure tank 70 becomes negative due to the negative pressure generated in the intake manifold 12, the negative pressure tank 70 is closed once the opening / closing valve 50 ′ is closed. Is also configured to continuously maintain the negative pressure. The on-off valve 5
Reference numeral 0'denotes a normally open solenoid valve having exactly the same function as that of the opening / closing valve 50, and a description thereof will be omitted here.

On the other hand, the return pipe 48 is provided with a normally open type spool valve 74 which is kept open by the biasing force of a spring 76. The negative pressure tank 70 and the pressure chamber 78 of the spool valve 74 are connected by a negative pressure pipe 72. That is, in the second embodiment, in the blow-by gas recirculation device, when the opening / closing valve 50 ′ is closed by energization during the operation of the engine 1, the negative pressure in the negative pressure tank 70 causes the spool valve 74 to close. Return pipe 48
Is shut off, and on the other hand, when the on-off valve 50 'is de-energized and the negative pressure tank 70 becomes atmospheric pressure, the spool valve 74 is automatically opened and the return pipe 48 is communicated. .

The operation of the blow-by gas recirculation device according to the second embodiment, that is, the opening / closing control of the electromagnetic opening / closing valve 50 'will be described below. Here, since the control routine (FIG. 4) in the first embodiment is applied as it is, only the operation portion different from the first embodiment will be described. When the determination result of step S10 is true (Yes), the engine 1 is not in the stopped state and is in the normal operating state, and it is determined that the pressure in the negative pressure tank 70 is maintained at a predetermined negative pressure or more, In step S12, the on-off valve 5
Energize 0'to close the valve. When the on-off valve 50 ′ is closed when it is determined that the normal operation state is set as described above, the pressure in the negative pressure tank 70 that has been negative pressure due to the negative pressure generated in the intake manifold 12 before the valve is closed. Is maintained at the negative pressure as it is, and unlike the fluctuating negative pressure in the intake manifold 12, the stable negative pressure forcibly closes the spool valve 74 and stably shuts off the return pipe 48. It This reliably prevents the oil component separated from the blow-by gas from being stored in the oil reservoir 46 and being sucked into the intake system.

On the other hand, the determination result of step S10 is false (N
When it is determined in o) that the engine 1 is in the stopped state, the energization of the on-off valve 50 'is released in step S14. When the on / off valve 50 ′ is deenergized when it is determined that the on / off valve 50 ′ is in the stopped state,
Will automatically open, and at this time the pressure in the intake manifold 12 is close to atmospheric pressure,
The pressure chamber 78 of the spool valve 74 is close to the atmospheric pressure, and the spool valve 74 is forcibly opened by the urging force of the spring 76 so that the return pipe 48 communicates. As a result, the oil component stored in the oil reservoir 46 is reliably returned to the oil pan 3c through the return pipe 48 without being sucked into the intake system.

Therefore, also in the second embodiment, the accumulation of deposits on the wall of the intake port 13 and the intake valve 20 is surely reduced, and the malfunction of the intake valve 20 and the decrease of intake efficiency are suppressed. It Also, especially the second
In the embodiment, since the opening / closing valve 50 'is applied to the air passage instead of the liquid passage as in the first embodiment, the opening / closing valve 50' may be small and inexpensive with low power consumption. Intake valve 20 while saving power
Accumulation of deposit on the wall of the intake port 13 can be reliably reduced.

In the second embodiment, instead of the electromagnetic on-off valve 50 ', a one-way check valve from the negative pressure tank 70 to the intake manifold 12 may be used. In this case, similar to the electromagnetic on-off valve 50 ', the pressure in the negative pressure tank 70 can be maintained at a stable negative pressure, but a more inexpensive system can be configured.

Although the description is finished above, the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the normally open solenoid valve is used as the on-off valve 50 and the on-off valve 50 '. However, if power saving can be realized, not only at the time of closing the valve but also at the time of opening the valve. You may make it use the usual solenoid valve which energizes.

Further, in the above embodiment, the opening / closing valve 50 as shown in FIG. 3 is used as the opening / closing means.
The on-off valve 50 may be a butterfly valve or the like. Further, in the above embodiment, the cylinder injection type gasoline engine is adopted as the engine 1. However, the engine 1 may be any type, and may be an intake pipe injection type gasoline engine or a diesel engine.

The warning means is not limited to the warning lamp 64, and may be any means as long as it issues a warning.

[0046]

As described in detail above, according to the blow-by gas recirculation system for an internal combustion engine of claim 1 of the present invention,
During operation of the internal combustion engine, the liquid return passage is blocked by the opening / closing means to reliably prevent the liquid component in the blow-by gas from entering the intake system.On the other hand, when the internal combustion engine is stopped, the intake air Since the system has returned to atmospheric pressure,
By connecting the liquid return passage with the opening / closing means, the liquid component stored in the gas-liquid separator can be surely returned to the liquid reservoir. As a result, it is possible to reliably reduce the accumulation of deposits on the intake valve and the intake port wall, and to prevent malfunction of the intake valve and reduction of intake efficiency.

Further, according to the blow-by gas recirculation system for an internal combustion engine of claim 2, since the normally open type electromagnetic valve is used, the electromagnetic valve is closed by energizing during operation of the internal combustion engine. By shutting off the liquid return passage, it is possible to reliably prevent the liquid component in the blow-by gas from entering the intake system.On the other hand, when the internal combustion engine is stopped, the solenoid valve is de-energized and the solenoid valve is automatically activated. It is possible to surely return the liquid component stored in the gas-liquid separator to the liquid reservoir by opening the valve and communicating the liquid return passage. As a result, even if the power is turned off when the internal combustion engine is stopped, the liquid return passage can be reliably communicated, and power is saved while deposits are deposited on the intake valve and intake port wall. Can be reliably reduced.

According to the blow-by gas recirculation system for an internal combustion engine of the third aspect, when the stored amount of the liquid component exceeds a predetermined amount, a warning is issued and the driver is informed that the internal combustion engine should be stopped. It is possible to prevent excessive storage and overflow of the liquid component stored in the gas-liquid separator.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a blow-by gas recirculation device for an internal combustion engine according to the present invention, which is mounted on a vehicle.

FIG. 2 is a diagram showing a variation of an oil separator.

FIG. 3 is a view showing a normally open electromagnetic on-off valve.

FIG. 4 is a flowchart showing a control routine of solenoid valve control according to the present invention.

FIG. 5 is a diagram showing a part of a schematic configuration diagram of a blow-by gas recirculation device for an internal combustion engine according to a second embodiment of the present invention.

[Explanation of symbols]

1 engine body 2 cylinder head 3 cylinder block 3a cylinder 3b crankcase 3c oil pan 4 pistons 12 intake manifold 13 Intake port 14 Throttle valve 40 PCV valve 44 Oil separator 46 Oil reservoir 48 Return pipe 50 open / close valve 60 ECU (electronic control unit) 64 Warning lamp

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3G015 AA06 BD12 BD13 BD24 BE03                       BE11 BE12 BF05 BF08 BF10                       CA04 CA06 FA04 FB00 FD00                       FE02

Claims (3)

[Claims] 1. A recirculation passage for recirculating blow-by gas to an intake system, a gas-liquid separator interposed in the recirculation passage for separating and storing a liquid component in the blow-by gas, and connected to the gas-liquid separator. A liquid return passage for returning the stored liquid component to the liquid reservoir, and is interposed between the gas-liquid separator and the liquid return passage,
An opening / closing means for communicating and blocking the liquid return passage, an operating state detecting means for detecting an operating state of the internal combustion engine, and an opening / closing means for detecting the operation of the internal combustion engine by the operating state detecting means. A blow-by gas recirculation apparatus for an internal combustion engine, comprising: a control unit that shuts off the return passage and connects the liquid return passage when the stopped state of the internal combustion engine is detected. 2. The opening / closing means includes a solenoid valve which is closed by energization while being normally open when not energized, and the control means detects the operating state of the internal combustion engine by the operating state detecting means. The blow-by gas recirculation system for an internal combustion engine according to claim 1, wherein the solenoid valve is closed by energizing the liquid return passage only when it is turned off. 3. A storage amount detecting means for detecting a storage amount of a liquid component stored in the gas-liquid separator, and a warning means, wherein the warning means is a liquid detected by the storage amount detecting means. The blow-by gas recirculation device for an internal combustion engine according to claim 1 or 2, wherein a warning is issued when the stored amount of the components exceeds a predetermined amount.