JPH0678725B2 - Blow-by gas reduction device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blow-by gas reducing apparatus for an internal combustion engine, and more particularly to controlling the flow rate of the blow-by gas to be reduced according to the atmospheric pressure at which the internal combustion engine is located. is there.

[Conventional technology]

Heretofore, various blow-by gas reducing devices of this type have been used. That is, since the blow-by gas generated in the crankcase of the internal combustion engine is directly discharged to the atmosphere as a cause of air pollution and the like, the generated blow-by gas is returned to the intake passage side of the internal combustion engine again.

The present invention has been made with respect to this blow-by gas reducing apparatus.

As a result of various studies conducted by the present inventors on the blow-by gas reducing apparatus, it was found that the engine oil in the internal combustion engine was consumed more in the state where the internal combustion engine was operated at high altitude. That is, when the inventors of the present invention have operated the internal combustion engine equipped with the blow-by gas reducing device under various conditions, the engine oil used for lubricating the internal combustion engine in a state in which the internal combustion engine is operated in the highland as compared with the operation in the flatland. It has been confirmed that the consumption of the is increasing.

The present inventors have conducted various studies on this cause, and as one of the causes, when the internal combustion engine is operated in a highland, the engine oil escapes to the blow-by gas reduction passage side, and as a result, the engine It was found that it was absorbed by the cylinder and burned there.

The present inventors have made the following consideration regarding this cause. That is, it is recognized that the reduction flow rate of the blow-by gas is reduced based on the pressure in the crankcase of the internal combustion engine, that is, the pressure difference between the blow-by gas generating portion and the intake passage. The intake air pressure in the intake passage is close to atmospheric pressure. Therefore,
As the internal combustion engine operates at high altitudes, intake air pressure decreases. This decrease in intake air pressure means an increase in the differential pressure between the internal pressure of the crankcase of the internal combustion engine and the intake air pressure. Therefore, it was confirmed that the differential pressure between both ends of the blow-by gas returning passage becomes large in a state of being operated at high altitude, and as a result, the blow-by gas returning amount becomes larger than necessary.

[Problems to be solved by the invention]

The present invention has been devised in view of the above points, and an object thereof is to prevent the reduction flow rate of blow-by gas from increasing even in highlands. In other words, the present invention is characterized in that when the internal combustion engine is operated at high altitude, that is, when the intake air pressure is reduced, the passage cross-sectional area of the blow-by gas reducing passage is reduced to suppress an increase in the blow-by gas reducing flow rate. To do.

[Action]

In the present invention, a control valve is arranged in the blowby gas returning passage. The control valve detects the atmospheric pressure and reduces the passage area of the blow-by gas returning passage as the atmospheric pressure decreases. Therefore, in the device of the present invention, the blow-by gas reducing flow rate does not increase more than necessary even when the internal combustion engine is operated at high altitude.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 100 indicates an internal combustion engine. Reference numeral 101 is a cylinder block of the internal combustion engine 100, and 102 is a crankcase. 103 is a cylinder head, and the cylinder head 103 and the crankcase are connected by a blow-by gas passage 104.

110 is an intake valve and 111 is an exhaust valve. A throttle valve 121 is arranged in the middle of the intake passage 120, and an air filter 122 is arranged further upstream thereof. Therefore, normal air filtered by the air filter 122 is sucked into the intake passage 120.

The exhaust valve 111 communicates with the exhaust manifold 131. A muffler (not shown) is disposed in the middle of the exhaust manifold, and the muffler is open to the atmosphere through the muffler. A blow-by gas opening 150 is provided in the cylinder head 103, and the blow-by gas opening is connected to a blow-by gas opening 151 provided in the intake passage 120 via a blow-by gas returning passage 152. A control valve 200 as shown in FIG. 2 is disposed in the middle of the blow-by gas returning passage 152.

The control valve 200 includes a housing 201 made of an aluminum alloy and a vacuum bellows 202 arranged in the housing 201. The vacuum bellows is arranged in the atmospheric pressure chamber 203 of the housing 201. The atmospheric pressure chamber 203 is constantly open to the atmosphere through the atmospheric opening 204, and therefore the atmospheric pressure chamber is always under atmospheric pressure.

The blow-by gas return passage chamber 2 is simultaneously in the housing 201.
10 is formed, and the return passage chamber 210 and the atmospheric pressure chamber 203 are formed.
And the partition wall 211. Reference numeral 220 is a control valve rod that is in sliding contact with this partition wall. A valve body 221 is formed at the tip of the control valve rod. The control valve body faces the valve seat portion 222 formed in the housing 201.

The valve seat portion 222 forms a part of the blow-by gas returning passage 152. Therefore, the blow-by gas returning passage 152 is abutted and separated between the control valve main body 221 and the valve seat portion and a change in the interval thereof.
The passage area of is changed.

A compression spring 240 is arranged in the atmospheric pressure chamber 203,
The compression spring 240 is connected to the rod 220 via the washer 241.
Is always pressed against the vacuum bellows 202 side. 243 is an adjusting screw, and the position of the vacuum bellows 202 is controlled by the adjusting screw 243.

The vacuum bellows has a vacuum inside, so that the volume of the vacuum bellows expands as the pressure applied to the vacuum bellows decreases. That is, when the pressure in the atmospheric pressure chamber is high, the vacuum bellows 202 is contracted, and as a result, the rod 220 is displaced leftward in FIG. This state, in turn, means that the valve body 221 is largely separated from the valve seat portion 222, which means that the passage area of the blow-by gas returning passage is large.

However, when the pressure in the atmospheric pressure chamber becomes low, the vacuum bellows 202 expands its volume, for example, in a state where the atmospheric pressure chamber is placed in a highland and the atmospheric pressure becomes low. At this time, the volume expansion of the vacuum bellows 202 is transmitted to the rod 220, which in turn displaces the valve body 221 to the right in FIG.
This means that the passage area of the blowby gas returning passage is reduced.

FIG. 3 is an explanatory diagram showing this state. In the figure, the solid line S indicates the cross-sectional area of the blow-by gas returning passage portion formed between the valve body portion 221 and the valve seat portion 222. As is clear from FIG. 3, the opening area S decreases as the atmospheric pressure decreases.

Next, the operation of the above component device will be described.

In the internal combustion engine 100, the piston 180 is replaced by the cylinder block 181.
Make a round trip inside. With this reciprocation, intake gas containing fuel is introduced into the cylinder through the intake valve from the intake passage. In the compression explosion process, the exhaust gas is discharged to the exhaust manifold 131 side via the exhaust valve 111.

In this compression process, blow-by gas may leak from the side surface of the piston 180 to the inside of the crankcase 102.
The leaked blow-by gas is then guided from the passage 104 to the blow-by gas hole 150 side and then returned to the intake passage 120 side via the blow-by gas returning passage 152.

The flow rate of the blow-by gas flowing through the blow-by gas returning passage 152 is determined mainly based on the differential pressure between the pressure inside the crankcase 102 and the pressure inside the intake passage 120. That is, when the pressure in the intake passage is low, this differential pressure increases, and the blow-by gas passage tends to increase in general. However, in the case of this example, since the control valve 200 is disposed in the middle of the blow-by gas returning passage 152, the third valve
As shown in the figure, the blow-by gas reduction flow rate Q is always kept constant regardless of increase or decrease in atmospheric pressure.

That is, the vacuum bellows 202 has an enormous volume when the atmospheric pressure is low, in other words, when the internal combustion engine is operated at high altitude. This volume expansion is caused by the valve body 2 via the rod 220.
21 to thereby reduce the cross-sectional area of the blowby gas returning passage. Due to this decrease in cross-sectional area, flow resistance is given to the blow-by gas flowing in the blow-by gas returning passage 152.

Therefore, even if the pressure on the intake passage 120 side decreases and the differential pressure between both ends of the blow-by gas returning passage 152 increases,
The increase in the differential pressure is controlled by the control valve 2 in the blowby gas returning passage 152.
Distribution resistance due to 00 will be compensated. As a result, despite the increase in the differential pressure, the blow-by gas return passage
The flow rate inside 152 is always kept constant.

Not only the blow-by gas reducing flow rate is maintained at a constant value as shown in FIG. 3, but the blow-by gas reducing flow rate may be decreased. That is, when the internal combustion engine is operated at a high altitude, the required flow rate of intake air also decreases as the intake air density decreases. Therefore, the blow-by gas reduction flow rate may be reduced as the required flow rate of the intake air is reduced. This is possible by controlling the set value of the vacuum bellows 202 in FIG. This state is shown by a broken line in FIG.

In the above example, one end of the blow-by gas returning passage 152 was opened upstream of the throttle valve 121 in the intake passage 120. However, as shown in FIG. 4, the control valve 200 is arranged downstream of the throttle valve 121. You may make it open. Further, as shown in FIG. 4, an air passage 230 for guiding air directly from the air cleaner to the internal combustion engine side may be provided, and the control valve 200 may be arranged in the middle of this air passage.

Further, as shown in FIG. 5, the blow-by gas returning passage
A bypass passage 159 is provided on the way 152, and a portion 1 of the blow-by gas returning passage arranged in parallel with the bypass passage 159
The control valve 250 may be arranged on the way. In this case, a throttle portion 157 is provided in the bypass passage 159 so that the flow resistance when flowing through the bypass passage becomes equal to or higher than a predetermined value.

Particularly, in the embodiment shown in FIG. 5, the control valve 250 is formed by a solenoid valve. That is, the control valve 250 is adapted to reduce the passage cross-sectional area based on the electrical signal applied to it. As shown in FIG. 5, the control valve 250 variably controls the opening area based on the electric signal from the control device 253.
The control device 253 receives a signal from the atmospheric pressure sensor 254 or the like,
The output voltage is adjusted based on the signal.

〔The invention's effect〕

As described above, in the device of the present invention, the control valve is provided in the middle of the blow-by gas returning passage, and the flow rate of the blow-by gas flowing in the blow-by gas returning passage is given a large flow resistance as the atmospheric pressure decreases. Therefore, even if the internal combustion engine is operated at high altitude, more blow-by gas than necessary is not reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the invention, and FIG.
FIG. 3 is a sectional view showing the control valve shown in the figure, FIG. 3 is an explanatory view showing the operation of the control valve shown in FIG. 2, and FIGS. 4 and 5 are explanatory views showing another embodiment of the device of the present invention. 102 …… Crank case, 152 Blow-by gas return passage, 20
0 …… Control valve, 202 …… Vacuum bellows, 221 …… Valve element, 222…
… Valve seat.

Claims (1)

[Claims] 1. A blow-by gas returning passage that connects a crank case of an internal combustion engine and an intake passage, and a control valve disposed in the middle of the blow-by gas returning passage. A blow-by gas returning apparatus for an internal combustion engine, characterized in that the passage area of the blow-by gas returning passage is reduced as the pressure decreases.